Felsher Lab In the Division of Oncology

The Felsher Laboratory Publications

Featured Publications

Anal Chem. 2013 Apr 5. [Epub ahead of print]

Characterization of MYC-Induced Tumorigenesis by in situ Lipid Profiling.

Perry RH, Bellovin DI, Shroff EH, Ismail AI, Zabuawala T, Felsher DW, Zare RN.

We apply desorption electrospray ionization mass spectrometry imaging (DESI-MSI) to provide an in situ lipidomic profile of genetically modified tissues from a conditional transgenic mouse model of MYC-induced hepatocellular carcinoma (HCC). This unique, label-free approach of combining DESI-MSI with the ability to turn specific genes on and off has led to the discovery of highly specific lipid molecules associated with MYC-induced tumor onset. We are able to distinguish normal from MYC-induced malignant cells. Our approach provides a strategy to define a precise molecular picture at a resolution of about 200 microns that may be useful in identifying lipid molecules that define how the MYC oncogene initiates and maintains tumorigenesis. PMID: 23560736  [PubMed - as supplied by publisher] Lancet Oncol. 2013 Apr;14(4):270-1. doi: 10.1016/S1470-2045(13)70070-6. Epub 2013
Mar 13.

Role of MYCN in retinoblastoma.

Felsher DW.

Stanford University School of Medicine, Stanford, CA, USA. Electronic address:
dfelsher@stanford.edu.
PMID: 23498720  [PubMed - in process]

Sci Transl Med. 2013 Jan 30;5(170):170ra13. doi: 10.1126/scitranslmed.3004912.

CD271(+) bone marrow mesenchymal stem cells may provide a niche for dormant Mycobacterium tuberculosis.

Das B, Kashino SS, Pulu I, Kalita D, Swami V, Yeger H, Felsher DW, Campos-Neto A.

Division of Oncology, Departments of Medicine and Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA. bikuldas@stanford.edu

Mycobacterium tuberculosis (Mtb) can persist in hostile intracellular microenvironments evading immune cells and drug treatment. However, the protective cellular niches where Mtb persists remain unclear. We report that Mtb may maintain long-term intracellular viability in a human bone marrow (BM)-derived CD271(+)/CD45(-) mesenchymal stem cell (BM-MSC) population in vitro. We also report that Mtb resides in an equivalent population of BM-MSCs in a mouse model of dormant tuberculosis infection. Viable Mtb was detected in CD271(+)/CD45(-) BM-MSCs isolated from individuals who had successfully completed months of anti-Mtb drug treatment. These results suggest that CD271(+) BM-MSCs may provide a long-term protective intracellular niche in the host in which dormant Mtb can reside. PMCID: PMC3616630 PMID: 23363977  [PubMed - in process]

Adv Exp Med Biol. 2013;734:91-107. doi: 10.1007/978-1-4614-1445-2_6.

Tumor dormancy, oncogene addiction, cellular senescence, and self-renewal programs.

Bellovin DI, Das B, Felsher DW.

Department of Medicine and Pathology, Stanford University School of Medicine, Stanford, CA 94305-5151, USA.

Cancers are frequently addicted to initiating oncogenes that elicit aberrant cellular proliferation, self-renewal, and apoptosis. Restoration of oncogenes to
normal physiologic regulation can elicit dramatic reversal of the neoplastic phenotype, including reduced proliferation and increased apoptosis of tumor cells (Science 297(5578):63-64, 2002). In some cases, oncogene inactivation is associated with compete elimination of a tumor. However, in other cases, oncogene inactivation induces a conversion of tumor cells to a dormant state that is associated with cellular differentiation and/or loss of the ability to self-replicate. Importantly, this dormant state is reversible, with tumor cells regaining the ability to self-renew upon oncogene reactivation. Thus, understanding the mechanism of oncogene inactivation-induced dormancy may be crucial for predicting therapeutic outcome of targeted therapy. One important mechanistic insight into tumor dormancy is that oncogene addiction might involve regulation of a decision between self-renewal and cellular senescence. Recent evidence suggests that this decision is regulated by multiple mechanisms that include tumor cell-intrinsic, cell-autonomous mechanisms and host-dependent, tumor cell-non-autonomous programs. In particular, the tumor microenvironment, which is known to be critical during tumor initiation, prevention, and progression also appears to dictate when oncogene inactivation elicits the permanent loss of self-renewal through induction of cellular senescence. Thus, oncogene addiction may be best modeled as a consequence of the interplay amongst cell autonomous and host-dependent programs that define when a therapy will result in tumor dormancy. PMID: 23143977  [PubMed - indexed for MEDLINE]

PMID: 23178486  [PubMed - as supplied by publisher]

BMJ Case Rep. 2012 Sep 7;2012.

Cryptococcal osteomyelitis and meningitis in a patient with non-hodgkin's lymphoma treated with PEP-C.

To CA, Hsieh RW, McClellan JS, Howard W, Fischbein NJ, Brown JM, Felsher DW, Fan AC.

Department of Internal Medicine, Scripps Clinic/Green Hospital, La Jolla, California, USA.

The authors present the first case report of a patient with lymphoma who developed disseminated cryptococcal osteomyelitis and meningitis while being treated with the PEP-C (prednisone, etoposide, procarbazine and cyclophosphamide) chemotherapy regimen. During investigation of fever and new bony lesions, fungal culture from a rib biopsy revealed that the patient had cryptococcal osteomyelitis. Further evaluation demonstrated concurrent cryptococcal meningitis. The patient's disseminated cryptococcal infections completely resolved after a full course of antifungal treatment. Cryptococcal osteomyelitis is itself an extremely rare diagnosis, and the unique presentation with concurrent cryptococcal meningitis in our patient with lymphoma was likely due to his PEP-C treatment. It is well recognised that prolonged intensive chemotherapeutic regimens place patients at risk for atypical infections; yet physicians should recognise that even chronic low-dose therapies can put patients at risk for fungal infections. Physicians should consider fungal infections as part of the infectious investigation of a lymphopaenic patient on PEP-C. PMID: 22962380  [PubMed - in process]

Stem Cells. 2012 Aug;30(8):1685-95. doi: 10.1002/stem.1142.

HIF-2α suppresses p53 to enhance the stemness and regenerative potential of human embryonic stem cells.

Das B, Bayat-Mokhtari R, Tsui M, Lotfi S, Tsuchida R, Felsher DW, Yeger H.

Division of Oncology, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA. bikuldas@stanford.edu

Human embryonic stem cells (hESCs) have been reported to exert cytoprotective activity in the area of tissue injury. However, hypoxia/oxidative stress prevailing in the area of injury could activate p53, leading to death and differentiation of hESCs. Here we report that when exposed to hypoxia/oxidative stress, a small fraction of hESCs, namely the SSEA3+/ABCG2+ fraction undergoes a transient state of reprogramming to a low p53 and high hypoxia inducible factor (HIF)-2Œ± state of transcriptional activity. This state can be sustained for a period of 2 weeks and is associated with enhanced transcriptional activity of Oct-4 and Nanog, concomitant with high teratomagenic potential. Conditioned medium obtained from the post-hypoxia SSEA3+/ABCG2+ hESCs showed cytoprotection both in vitro and in vivo. We termed this phenotype as the "enhanced stemness" state. We then demonstrated that the underlying molecular mechanism of this transient phenotype of enhanced stemness involved high Bcl-2, fibroblast growth factor (FGF)-2, and MDM2 expression and an altered state of the p53/MDM2 oscillation system. Specific silencing of HIF-2Œ± and p53 resisted the reprogramming of SSEA3+/ABCG2+ to the enhanced stemness phenotype. Thus, our studies have uncovered a unique transient reprogramming activity in hESCs, the enhanced stemness reprogramming where a highly cytoprotective and undifferentiated state is achieved by transiently suppressing p53 activity. We suggest that this transient reprogramming is a form of stem cell altruism that benefits the surrounding tissues during the process of tissue regeneration. Copyright ¬© 2012 AlphaMed Press. PMCID: PMC3584519 PMID: 22689594  [PubMed - indexed for MEDLINE]

Lab Chip. 2012 Jun 21;12(12):2190-8. doi: 10.1039/c2lc21290k. Epub 2012 May 8.

High throughput automated chromatin immunoprecipitation as a platform for drug screening and antibody validation.

Wu AR, Kawahara TL, Rapicavoli NA, van Riggelen J, Shroff EH, Xu L, Felsher DW, Chang HY, Quake SR.

Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.

Chromatin immunoprecipitation (ChIP) is an assay for interrogating protein-DNA interactions that is increasingly being used for drug target discovery and screening applications. Currently the complexity of the protocol and the amount of hands-on time required for this assay limits its use to low throughput applications; furthermore, variability in antibody quality poses an additional obstacle in scaling up ChIP for large scale screening purposes. To address these challenges, we report HTChIP, an automated microfluidic-based platform for performing high-throughput ChIP screening measurements of 16 different targets simultaneously, with potential for further scale-up. From chromatin to analyzable PCR results only takes one day using HTChIP, as compared to several days up to one week for conventional protocols. HTChIP can also be used to test multiple antibodies and select the best performer for downstream ChIP applications, saving time and reagent costs of unsuccessful ChIP assays as a result of poor antibody quality. We performed a series of characterization assays to demonstrate that HTChIP can rapidly and accurately evaluate the epigenetic states of a cell, and that it is sensitive enough to detect the changes in the epigenetic state induced by a cytokine stimulant over a fine temporal resolution. With these results, we believe that HTChIP can introduce large improvements in routine ChIP, antibody screening, and drug screening efficiency, and further facilitate the use of ChIP as a valuable tool for research and discovery. PMID: 22566096  [PubMed - indexed for MEDLINE]

Clin Exp Immunol. 2012 Feb;167(2):188-94.

Immunology in the clinic review series; focus on cancer: multiple roles for the immune system in oncogene addiction.

Bachireddy P, Rakhra K, Felsher DW.

Department of Medicine, Brigham and Women's Hospital/Harvard Medical School, Boston, MA, USA.

Despite complex genomic and epigenetic abnormalities, many cancers are irrevocably dependent on an initiating oncogenic lesion whose restoration to a normal physiological activation can elicit a dramatic and sudden reversal of their neoplastic properties. This phenomenon of the reversal of tumorigenesis has been described as oncogene addiction. Oncogene addiction had been thought to occur largely through tumour cell-autonomous mechanisms such as proliferative arrest, apoptosis, differentiation and cellular senescence. However, the immune system plays an integral role in almost every aspect of tumorigenesis, including tumour initiation, prevention and progression as well as the response to
therapeutics. Here we highlight more recent evidence suggesting that oncogene addiction may be integrally dependent upon host immune-mediated mechanisms, including specific immune effectors and cytokines that regulate tumour cell senescence and tumour-associated angiogenesis. Hence, the host immune system is
essential to oncogene addiction PMCID: PMC3278684 PMID: 22235994  [PubMed - indexed for MEDLINE]

Oncotarget. 2012 Jan;3(1):58-66.

"Picolog," a synthetically-available bryostatin analog, inhibits growth of
MYC-induced lymphoma in vivo.

DeChristopher BA, Fan AC, Felsher DW, Wender PA.

Departments of Chemistry and Chemical and Systems Biology, Stanford University, Stanford, CA 94305-5080.

Comment in Oncotarget. 2012 Feb;3(2):116-7.

Bryostatin 1 is a naturally occurring complex macrolide with potent anti-neoplastic activity. However, its extremely low natural occurrence has impeded clinical advancement. We developed a strategy directed at the design of simplified and synthetically more accessible bryostatin analogs. Our lead analog "picolog", can be step-economically produced. Picolog, compared to bryostatin, exhibited superior growth inhibition of MYC-induced lymphoma in vitro. A key mechanism of picolog's (and bryostatin's) activity is activation of PKC. A novel
nano-immunoassay (NIA) revealed that picolog treatment increased phospho-MEK2 in the PKC pathway. Moreover, the inhibition of PKC abrogated picolog's activity. Finally, picolog was highly potent at 100 micrograms/kg and well tolerated at doses ranging from 100 micrograms/kg to 1 milligram/kg in vivo for the treatment of our aggressive model of MYC-induced lymphoma. We provide the first in vivo validation that the bryostatin analog, picolog, is a potential therapeutic agent for the treatment of cancer and other diseases. PMCID: PMC3292892 PMID: 22308267  [PubMed - indexed for MEDLINE]

PLoS Genet. 2012;8(5) Epub 2012 May 24.

Twist1 suppresses senescence programs and thereby accelerates and maintains mutant Kras-induced lung tumorigenesis.

Tran PT, Shroff EH, Burns TF, Thiyagarajan S, Das ST, Zabuawala T, Chen J, Cho YJ, Luong R, Tamayo P, Salih T, Aziz K, Adam SJ, Vicent S, Nielsen CH, Withofs N, Sweet-Cordero A, Gambhir SS, Rudin CM, Felsher DW.

Department of Radiation Oncology and Molecular Radiation Sciences, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins Medicine, Baltimore, Maryland, United
States of America. tranp@jhmi.edu

KRAS mutant lung cancers are generally refractory to chemotherapy as well targeted agents. To date, the identification of drugs to therapeutically inhibit K-RAS have been unsuccessful, suggesting that other approaches are required. We demonstrate in both a novel transgenic mutant Kras lung cancer mouse model and in human lung tumors that the inhibition of Twist1 restores a senescence program inducing the loss of a neoplastic phenotype. The Twist1 gene encodes for a transcription factor that is essential during embryogenesis. Twist1 has been suggested to play an important role during tumor progression. However, there is no in vivo evidence that Twist1 plays a role in autochthonous tumorigenesis. Through two novel transgenic mouse models, we show that Twist1 cooperates with Kras(G12D) to markedly accelerate lung tumorigenesis by abrogating cellular senescence programs and promoting the progression from benign adenomas to adenocarcinomas. Moreover, the suppression of Twist1 to physiological levels is sufficient to cause Kras mutant lung tumors to undergo senescence and lose their neoplastic features. Finally, we analyzed more than 500 human tumors to demonstrate that TWIST1 is frequently overexpressed in primary human lung tumors. The suppression of TWIST1 in human lung cancer cells also induced cellular senescence. Hence, TWIST1 is a critical regulator of cellular senescence programs, and the suppression of TWIST1 in human tumors may be an effective example of pro-senescence therapy. PMCID: PMC3360067 PMID: 22654667  [PubMed - indexed for MEDLINE]

Proc Natl Acad Sci U S A. 2011 Oct 18

Lymphomas that recur after MYC suppression continue to exhibit oncogene addiction.

Choi PS, van Riggelen J, Gentles AJ, Bachireddy P, Rakhra K, Adam SJ, Plevritis SK, Felsher DW.

Division of Oncology, Department of Medicine and Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA.

The suppression of oncogenic levels of MYC is sufficient to induce sustained tumor regression associated with proliferative arrest, differentiation, cellular senescence, and/or apoptosis, a phenomenon known as oncogene addiction. However, after prolonged inactivation of MYC in a conditional transgenic mouse model of EŒº-tTA/tetO-MYC T-cell acute lymphoblastic leukemia, some of the tumors recur, recapitulating what is frequently observed in human tumors in response to targeted therapies. Here we report that these recurring lymphomas express either transgenic or endogenous Myc, albeit in many cases at levels below those in the original tumor, suggesting that tumors continue to be addicted to MYC. Many of the recurring lymphomas (76%) harbored mutations in the tetracycline transactivator, resulting in expression of the MYC transgene even in the presence of doxycycline. Some of the remaining recurring tumors expressed high levels of endogenous Myc, which was associated with a genomic rearrangement of the endogenous Myc locus or activation of Notch1. By gene expression profiling, we confirmed that the primary and recurring tumors have highly similar transcriptomes. Importantly, shRNA-mediated suppression of the high levels of MYC in recurring tumors elicited both suppression of proliferation and increased apoptosis, confirming that these tumors remain oncogene addicted. These results suggest that tumors induced by MYC remain addicted to overexpression of this oncogene. PMCID: PMC3198348 PMID: 21969595  [PubMed - indexed for MEDLINE]

Sci Transl Med. 2011 Oct 5;3(103)

Survival and death signals can predict tumor response to therapy after oncogene inactivation.

Tran PT, Bendapudi PK, Lin HJ, Choi P, Koh S, Chen J, Horng G, Hughes NP, Schwartz LH, Miller VA, Kawashima T, Kitamura T, Paik D, Felsher DW.

Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA.

Comment in Nat Rev Clin Oncol. 2011 Dec;8(12):691.

Cancers can exhibit marked tumor regression after oncogene inhibition through a phenomenon called "oncogene addiction." The ability to predict when a tumor will exhibit oncogene addiction would be useful in the development of targeted therapeutics. Oncogene addiction is likely the consequence of many cellular programs. However, we reasoned that many of these inputs may converge onaggregate survival and death signals. To test this, we examined conditionaltransgenic models of K-ras(G12D)--or MYC-induced lung tumors and lymphomacombined with quantitative imaging and an in situ analysis of biomarkers of proliferation and apoptotic signaling. We then used computational modeling based on ordinary differential equations (ODEs) to show that oncogene addiction could be modeled as differential changes in survival and death intracellular signals. Our mathematical model could be generalized to different imaging methods (computed tomography and bioluminescence imaging), different oncogenes (K-ras(G12D) and MYC), and several tumor types (lung and lymphoma). Our ODE model could predict the differential dynamics of several putative prosurvival and prodeath signaling factors [phosphorylated extracellular signal-regulated kinase 1 and 2, Akt1, Stat3/5 (signal transducer and activator of transcription 3/5), and p38] that contribute to the aggregate survival and death signals after oncogene inactivation. Furthermore, we could predict the influence of specific genetic lesions (p53⁻/⁻, Stat3-d358L, and myr-Akt1) on tumor regression after oncogene inactivation. Then, using machine learning based on support vector machine, we applied quantitative imaging methods to human patients to predict both their EGFR genotype and their progression-free survival after treatment with the targeted therapeutic erlotinib. Hence, the consequences of oncogene inactivation can be accurately modeled on the basis of a relatively small number of parameters that may predict when targeted therapeutics will elicit oncogene addiction after oncogene inactivation and hence tumor regression.
PMID: 21974937  [PubMed - indexed for MEDLINE]

PLoS One. 2011 May 6;6(5)
 
Functional interactions between retinoblastoma and c-MYC in a mouse model of hepatocellular carcinoma.

Saddic LA, Wirt S, Vogel H, Felsher DW, Sage J.

Department of Pediatrics, Stanford University, Stanford, California, United States of America.

Inactivation of the RB tumor suppressor and activation of the MYC family of oncogenes are frequent events in a large spectrum of human cancers. Loss of RB function and MYC activation are thought to control both overlapping and distinct cellular processes during cell cycle progression. However, how these two major
cancer genes functionally interact during tumorigenesis is still unclear. Here, we sought to test whether loss of RB function would affect cancer development in
a mouse model of c-MYC-induced hepatocellular carcinoma (HCC), a deadly cancer type in which RB is frequently inactivated and c-MYC often activated. We found that RB inactivation has minimal effects on the cell cycle, cell death, and differentiation features of liver tumors driven by increased levels of c-MYC. However, combined loss of RB and activation of c-MYC led to an increase in polyploidy in mature hepatocytes before the development of tumors. There was a trend for decreased survival in double mutant animals compared to mice developing c-MYC-induced tumors. Thus, loss of RB function does not provide a proliferative advantage to c-MYC-expressing HCC cells but the RB and c-MYC pathways may cooperate to control the polyploidy of mature hepatocytes. PMCID: PMC3089631 PMID: 21573126  [PubMed - indexed for MEDLINE]

J Biol Chem. 2011 Apr 1;286(13).

Reactive oxygen species regulate nucleostemin oligomerization and protein degradation.

Huang M, Whang P, Chodaparambil JV, Pollyea DA, Kusler B, Xu L, Felsher DW, Mitchell BS.

Department of Medicine, Divisions of Oncology and Hematology, Stanford University School of Medicine, Stanford, California 94305, USA.

Nucleostemin (NS) is a nucleolar-nucleoplasmic shuttle protein that regulates cell proliferation, binds p53 and Mdm2, and is highly expressed in tumor cells.
We have identified NS as a target of oxidative regulation in transformed hematopoietic cells. NS oligomerization occurs in HL-60 leukemic cells and Raji B lymphoblasts that express high levels of c-Myc and have high intrinsic levels of reactive oxygen species (ROS); reducing agents dissociate NS into monomers and dimers. Exposure of U2OS osteosarcoma cells with low levels of intrinsic ROS to hydrogen peroxide (H(2)O(2)) induces thiol-reversible disulfide bond-mediated oligomerization of NS. Increased exposure to H(2)O(2) impairs NS degradation, immobilizes the protein within the nucleolus, and results in detergent-insoluble NS. The regulation of NS by ROS was validated in a murine lymphoma tumor model in which c-Myc is overexpressed and in CD34+ cells from patients with chronic myelogenous leukemia in blast crisis. In both instances, increased ROS levels
were associated with markedly increased expression of NS protein and thiol-reversible oligomerization. Site-directed mutagenesis of critical cysteine-containing regions of nucleostemin altered both its intracellular localization and its stability. MG132, a potent proteasome inhibitor and activator of ROS, markedly decreased degradation and increased nucleolar retention of NS mutants, whereas N-acetyl-L-cysteine largely prevented the effects of MG132. These results indicate that NS is a highly redox-sensitive protein. Increased intracellular ROS levels, such as those that result from oncogenic transformation in hematopoietic malignancies, regulate the ability of NS to oligomerize, prevent its degradation, and may alter its ability to regulate cell proliferation. PMCID: PMC3064158 PMID: 21242306  [PubMed - indexed for MEDLINE]

Cancer Res. 2011 Mar 15;71(6):2286-97

MYC phosphorylation, activation, and tumorigenic potential in hepatocellular carcinoma are regulated by HMG-CoA reductase.

Cao Z, Fan-Minogue H, Bellovin DI, Yevtodiyenko A, Arzeno J, Yang Q, Gambhir SS, Felsher DW.

Division of Medical Oncology, Department of Medicine and Pathology, Molecular Imaging Program at Stanford, Stanford University, Stanford, California 94305, USA.

MYC is a potential target for many cancers but is not amenable to existing pharmacologic approaches. Inhibition of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase) by statins has shown potential efficacy against a number of cancers. Here, we show that inhibition of HMG-CoA reductase by atorvastatin (AT) blocks both MYC phosphorylation and activation, suppressing tumor initiation and growth in vivo in a transgenic model of MYC-induced hepatocellular carcinoma (HCC) as well as in human HCC-derived cell lines. To confirm specificity, we show that the antitumor effects of AT are blocked by cotreatment with the HMG-CoA reductase product mevalonate. Moreover, by using a
novel molecular imaging sensor, we confirm that inhibition of HMG-CoA reductase blocks MYC phosphorylation in vivo. Importantly, the introduction of phosphorylation mutants of MYC at Ser62 or Thr58 into tumors blocks their sensitivity to inhibition of HMG-CoA reductase. Finally, we show that inhibition of HMG-CoA reductase suppresses MYC phosphorylation through Rac GTPase. Therefore, HMG-CoA reductase is a critical regulator of MYC phosphorylation, activation, and tumorigenic properties. The inhibition of HMG-CoA reductase may be a useful target for the treatment of MYC-associated HCC as well as other tumors. PMCID: PMC3059327 PMID: 21262914 

Cancer Res. 2010 Dec 1;70(23):9837-45.

Definition of an enhanced immune cell therapy in mice that can target stem-like lymphoma cells.

Contag CH, Sikorski R, Negrin RS, Schmidt T, Fan AC, Bachireddy P, Felsher DW, Thorne SH.

Department of Pediatrics, Stanford University, Stanford, California, USA.

Current treatments of high-grade lymphoma often have curative potential, but unfortunately many patients relapse and develop therapeutic resistance. Thus, there remains a need for novel therapeutics that can target the residual cancer cells whose phenotypes are distinct from the bulk tumor and that are capable of reforming tumors from very few cells. Oncolytic viruses offer an approach to destroy tumors by multiple mechanisms, but they cannot effectively reach residual disease or micrometastases, especially within the lymphatic system. To address these limitations, we have generated immune cells infected with oncolytic viruses as a therapeutic strategy that can combine effective cellular delivery with synergistic tumor killing. In this study, we tested this approach against minimal disease states of lymphomas characterized by the persistence of cancer cells that display stem cell-like properties and resistance to conventional therapies. We found that the immune cells were capable of trafficking to and targeting residual cancer cells. The combination biotherapy used prevented relapse by creating a long-term, disease-free state, with acquired immunity to the tumor functioning as an essential mediator of this effect. Immune components necessary for this acquired immunity were identified. We further demonstrated that the dual biotherapy could be applied before or after conventional therapy. Our approach offers a potentially powerful new way to clear residual cancer cells, showing how restoring immune surveillance is critical for maintenance of a disease-free state. PMCID: PMC2999648 PMID: 20935221 

Cancer Cell. 2010 Nov 16;18(5):485-98. doi: 10.1016/j.ccr.2010.10.002. Epub 2010 Oct 28.

CD4(+) T cells contribute to the remodeling of the microenvironment required for sustained tumor regression upon oncogene inactivation.

Rakhra K, Bachireddy P, Zabuawala T, Zeiser R, Xu L, Kopelman A, Fan AC, Yang Q, Braunstein L, Crosby E, Ryeom S, Felsher DW.

Division of Oncology, Departments of Medicine, Pathology and Molecular Imaging, Stanford University School of Medicine, Stanford, CA 94305, USA.

Erratum in Cancer Cell. 2010 Dec 14;18(6):696.

Comment in Nat Rev Immunol. 2011 Jan;11(1):7.

Comment on Cancer Cell. 2010 Nov 16;18(5):403-5.

Oncogene addiction is thought to occur cell autonomously. Immune effectors are implicated in the initiation and restraint of tumorigenesis, but their role in oncogene inactivation-mediated tumor regression is unclear. Here, we show that an intact immune system, specifically CD4(+) T cells, is required for the induction of cellular senescence, shutdown of angiogenesis, and chemokine expression resulting in sustained tumor regression upon inactivation of the MYC or BCR-ABL oncogenes in mouse models of T cell acute lymphoblastic lymphoma and pro-B cell leukemia, respectively. Moreover, immune effectors knocked out for thrombospondins failed to induce sustained tumor regression. Hence, CD4(+) T cells are required for the remodeling of the tumor microenvironment through the expression of chemokines, such as thrombospondins, in order to elicit oncogene addiction. PMCID: PMC2991103 PMID: 21035406  [PubMed - indexed for MEDLINE]

Proc Natl Acad Sci U S A. 2010 Sep 7;107(36):15892-7.

Noninvasive molecular imaging of c-Myc activation in living mice.

Fan-Minogue H, Cao Z, Paulmurugan R, Chan CT, Massoud TF, Felsher DW, Gambhir SS.

Department of Radiology, Stanford University School of Medicine, CA 94305-5427, USA.

The cytoplasmic Myc protein (c-Myc) regulates various human genes and is dysregulated in many human cancers. Phosphorylation mediates the protein activation of c-Myc and is essential for the function of this transcription factor in normal cell behavior and tumor growth. To date, however, the targeting of Myc as a therapeutic approach for cancer treatment has been achieved primarily at the nonprotein level. We have developed a molecular imaging sensor for noninvasive imaging of c-Myc activity in living subjects using a split Firefly luciferase (FL) complementation strategy to detect and quantify the phosphorylation-mediated interaction between glycogen synthase kinase 3beta
(GSK3beta) and c-Myc. This sensor system consists of two fusion proteins, GSK 35-433-CFL and NFL-c-Myc, in which specific fragments of GSK3beta and c-Myc are
fused with C-terminal and N-terminal fragments of the split FL, respectively. The sensor detects phosphorylation-specific GSK3beta-c-Myc interaction, the imaging signal of which correlates with the steady-state and temporal regulation of c-Myc phosphorylation in cell culture. The sensor also detects inhibition of c-Myc activity via differential pathways, allowing noninvasive monitoring of c-Myc-targeted drug efficacy in intact cells and living mice. Notably, this drug inhibition is detected before changes in tumor size are apparent in mouse xenograft and liver tumor models. This reporter system not only provides an innovative way to investigate the role of functional c-Myc in normal and cancer-related biological processes, but also facilitates c-Myc-targeted drug development by providing a rapid quantitative approach to assessing cancer response to therapy in living subjects. PMCID: PMC2936612
PMID: 20713710

Genes Dev. 2010 Jun 15;24(12):1281-94

The interaction between Myc and Miz1 is required to antagonize TGFbeta-dependent autocrine signaling during lymphoma formation and maintenance.

van Riggelen J, Müller J, Otto T, Beuger V, Yetil A, Choi PS, Kosan C, Möröy T, Felsher DW, Eilers M.

Department of Medicine, Division of Oncology, Stanford University, School of Medicine, Stanford, California 94304, USA.

Comment in Nat Rev Cancer. 2010 Aug;10(8):532-3.

The Myc protein suppresses the transcription of several cyclin-dependent kinase inhibitors (CKIs) via binding to Miz1; whether this interaction is important for
Myc's ability to induce or maintain tumorigenesis is not known. Here we show that the oncogenic potential of a point mutant of Myc (MycV394D) that is selectively deficient in binding to Miz1 is greatly attenuated. Binding of Myc to Miz1 is continuously required to repress CKI expression and inhibit accumulation of trimethylated histone H3 at Lys 9 (H3K9triMe), a hallmark of cellular senescence, in T-cell lymphomas. Lymphomas that arise express high amounts of transforming growth factor beta-2 (TGFbeta-2) and TGFbeta-3. Upon Myc suppression, TGFbeta signaling is required to induce CKI expression and cellular senescence and suppress tumor recurrence. Binding of Myc to Miz1 is required to antagonize growth suppression and induction of senescence by TGFbeta. We demonstrate that, since lymphomas express high levels of TGFbeta, they are poised to elicit an autocrine program of senescence upon Myc inactivation, demonstrating that TGFbeta is a key factor that establishes oncogene addiction of T-cell lymphomas.
PMCID: PMC2885663 PMID: 20551174  [PubMed - indexed for MEDLINE]

Genes Cancer. 2010 Jun;1(6):597-604.
MYC Inactivation Elicits Oncogene Addiction through Both Tumor Cell-Intrinsic and Host-Dependent Mechanisms.

Felsher DW.

Division of Oncology, Departments of Medicine and Pathology, Stanford University, Stanford, CA, USA.

Tumorigenesis is generally caused by genetic changes that activate oncogenes or inactivate tumor suppressor genes. The targeted inactivation of oncogenes can be associated with tumor regression through the phenomenon of oncogene addiction. One of the most common oncogenic events in human cancer is the activation of the MYC oncogene. The inactivation of MYC may be a general and effective therapy for human cancer. Indeed, it has been experimentally shown that the inactivation of MYC can result in dramatic and sustained tumor regression in lymphoma, leukemia, osteosarcoma, hepatocellular carcinoma, squamous carcinoma, and pancreatic carcinoma through a multitude of mechanisms, including proliferative arrest,
terminal differentiation, cellular senescence, induction of apoptosis, and the shutdown of angiogenesis. Cell-autonomous and cell-dependent mechanisms have both been implicated, and recent results suggest a critical role for autocrine factors, including thrombospondin-1 and TGF-β. Hence, targeting the inactivation of MYC appears to elicit oncogene addiction and, thereby, tumor regression through both tumor cell-intrinsic and host-dependent mechanisms. PMCID: PMC2965623 PMID: 21037952

Nat Rev Cancer. 2010 Apr;10(4):301-9.

MYC as a regulator of ribosome biogenesis and protein synthesis.

van Riggelen J, Yetil A, Felsher DW.

Division of Oncology, Department of Medicine, Stanford University School of
Medicine, Stanford, California 94305, USA.

MYC regulates the transcription of thousands of genes required to coordinate a range of cellular processes, including those essential for proliferation, growth, differentiation, apoptosis and self-renewal. Recently, MYC has also been shown to serve as a direct regulator of ribosome biogenesis. MYC coordinates protein synthesis through the transcriptional control of RNA and protein components of ribosomes, and of gene products required for the processing of ribosomal RNA, the nuclear export of ribosomal subunits and the initiation of mRNA translation. We discuss how the modulation of ribosome biogenesis by MYC may be essential to its physiological functions as well as its pathological role in tumorigenesis.
PMID: 20332779

Nat Cell Biol. 2010 Jan;12(1):7-9.Myc and a Cdk2 senescence switch.

van Riggelen J, Felsher DW.

Cdk2 has been shown to have an unanticipated role in suppressing Myc-induced senescence. This has implications for how c-Myc overcomes failsafe mechanisms to induce tumorigenesis and suggests that the inhibition of Cdk2 may have therapeutic efficacy in the treatment of cancer. PMID: 20027199 

Rakhra K, Bachireddy P, Zabuawala T, Zeiser R, Xu L, Kopelman A, Fan AC, Yang Q, Braunstein L, Crosby E, Ryeom S, Felsher DW. CD4(+) T cells contribute to the remodeling of the microenvironment required for sustained tumor regression upon oncogene inactivation.Cancer Cell, Nov 16, 2010. [Pubmed Abstract]

Fan AC, Deb-Basu D, Orban M, Gotlib J, Natkunam Y, O’Neill R, Padua R, Xu L, Taketa D, Shirer AE, Beer S, Yee AX, Voehringer D, Felsher DW. Nano-fluidic Proteomic Assay for Serial Quantitative Analysis of Oncoprotein Expression and Phosphorylation in Clinical Specimens. Nature Medicine, Apr 12, 2009. [Pubmed Abstract]

van Riggelen J, Müller J, Otto T, Beuger V, Yetil A, Choi PS, Kosan C, Möröy T, Felsher DW, Eilers M. The interaction between Myc and Miz1 is required to antagonize TGFbeta-dependent autocrine signaling during lymphoma formation and maintenance. Genes Dev., Jun 15, 2010. [Pubmed Abstract]

Shachaf CM, Kopelman AM, Arvanitis C, Karlsson A, Beer S, Mandl S, Bachmann MH, Borowsky AD, Ruebner B, Cardiff RD, Yang Q, Bishop JM, Contag CH, Felsher DW. MYC inactivation uncovers pluripotent differentiation and tumour dormancy in hepatocellular cancer. Nature, Oct 10, 2004. [Pubmed Abstract]

Jain M, Arvanitis C, Chu K, Dewey W, Leonhardt E, Trinh M, Sundberg CD, Bishop JM, Felsher DW. Sustained loss of a neoplastic phenotype by brief inactivation of MYC. Science, Jul 5, 2002. [Full Text]

Felsher DW, Bishop JM. Reversible tumorigenesis by MYC in hematopoietic lineages. Mol Cell.Aug, 1999. [PubMed Abstract]

Additional Publications:

Cao Z, Fan-Minogue H, Bellovin DI, Yevtodiyenko A, Arzeno J, Yang Q, Gambhir SS, Felsher DW. MYC phosphorylation, activation, and tumorigenic potential in hepatocellular carcinoma are regulated by HMG-CoA reductase. Cancer Research, Mar 15, 2011. [Pubmed Abstract]

Müller J, Samans B, van Riggelen J, Fagà G, Peh K N R, Wei CL, Müller H, Amati B, Felsher D, Eilers M. TGFβ-dependent gene expression shows that senescence correlates with abortive differentiation along several lineages in Myc-induced lymphomas. Cell Cycle, Dec 1, 2010.[Pubmed Abstract]

Fan-Minogue H, Cao Z, Paulmurugan R, Chan CT, Massoud TF, Felsher DW, Gambhir SS.Noninvasive molecular imaging of c-Myc activation in living mice. Proc Natl Acad Sci U S A. Sep 7, 2010 [Pubmed Abstract]

Beer S, Bellovin DI, Lee JS, Komatsubara K, Wang LS, Koh H, Börner K, Storm TA, Davis CR, Kay MA, Felsher DW, Grimm D. Low-level shRNA cytotoxicity can contribute to MYC-induced hepatocellular carcinoma in adult mice. Molecular Therapeutics Jan, 2010. [Pubmed Abstract]

Liu Z, Fan AC, Rakhra K, Sherlock S, Goodwin A, Chen X, Yang Q, Felsher DW, Dai H.Supramolecular stacking of doxorubicin on carbon nanotubes for in vivo cancer therapy. Angew Chem Int Ed Engl. 2009. [Pubmed Abstract]

Tran PT, Felsher DW.  The current STATe of biomarkers to predict the response to anti-angiogenic therapies.  Cancer Biol Ther. 2008 Dec;7(12):2004-6.

Felsher DW. Reversing cancer from inside and out: oncogene addiction, cellular senescence, and the angiogenic switch.  Lymphat Res Biol. 2008;6(3-4):149-54. Review. [Pubmed Abstract]

Arvanitis C, Bendapudi PK, Tseng JR, Gambhir SS, Felsher DW.  (18)F and (18)FDG PET imaging of osteosarcoma to non-invasively monitor in situ changes in cellular proliferation and bone differentiation upon MYC inactivation.  Cancer Biol Ther. 2008 Dec;7(12):1947-51. [Pubmed Abstract]

Felsher DW.  Tumor dormancy and oncogene addiction.  APMIS. 2008 Jul-Aug;116(7-8):629-37. Review. [Pubmed Abstract]

Fan AC, Goldrick MM, Ho J, Liang Y, Bachireddy P, Felsher DW. A quantitative PCR method to detect blood microRNAs associated with tumorigenesis in transgenic mice.  Mol Cancer. 2008 Sep 30;7:74. [Pubmed Abstract]

Shachaf CM, Gentles AJ, Elchuri S, Sahoo D, Soen Y, Sharpe O, Perez OD, Chang M, Mitchel D, Robinson WH, Dill D, Nolan GP, Plevritis SK, Felsher DW.  Genomic and proteomic analysis reveals a threshold level of MYC required for tumor maintenance. Cancer Res. 2008 Jul 1;68(13):5132-42. [Pubmed Abstract]

Beer S, Komatsubara K, Bellovin DI, Kurobe M, Sylvester K, Felsher DW.  Hepatotoxin-induced changes in the adult murine liver promote MYC-induced tumorigenesis.  PLoS ONE. 2008 Jun 18;3(6):e2493. [Pubmed Abstract]

Wu CH, Sahoo D, Arvanitis C, Bradon N, Dill DL, Felsher DW.  Combined analysis of murine and human microarrays and ChIP analysis reveals genes associated with the ability of MYC to maintain tumorigenesis. PLoS Genet. 2008 Jun 6;4(6):e1000090. [Pubmed Abstract]

Tran TP, Fan AC, Bendapudi PK, Koh S, Komatsubara K, Chen J, Horng G, Bellovin DI, Giuriato S, Wang CS, Whitsett JA, Felsher DW. Combined Inactivation of MYC and K-Ras oncogenes reverses tumorigenesis in lung ade nocarcinomas and lymphomas. PLoS ONE. 2008 May 7;3(5):e2125. [Pubmed Abstract]

Felsher DW.  Oncogene addiction versus oncogene amnesia: perhaps more than just a bad habit? Cancer Res. 2008 May 1;68(9):3081-6. Review.[Pubmed Abstract]

Opavsky R, Tsai SY, Guimond M, Arora A, Opavska J, Becknell B, Kaufmann M, Walton NA, Stephens JA, Fernandez SA, Muthusamy N, Felsher DW, Porcu P, Caligiuri MA, Leone G. Specific tumor suppressor function for E2F2 in Myc-induced T cell lymphomagenesis. Proc Natl Acad Sci U S A. 2007 Sep 25;104(39):15400-5. [Pubmed Abstract]

Gao P, Zhang H, Dinavahi R, Li F, Xiang Y, Raman V, Bhujwalla ZM, Felsher DW, Cheng L, Pevsner J, Lee LA, Semenza GL, Dang CV. HIF-dependent antitumorigenic effect of antioxidants in vivo. Cancer Cell. 2007 Sep;12(3):230-8. [Pubmed Abstract]

Wu CH, van Riggelen J, Yetil A, Fan AC, Bachireddy P, Felsher DW.  Cellular senescence is an important mechanism of tumor regression upon c-Myc inactivation.  Proc Natl Acad Sci U S A. 2007 Aug 7;104(32):13028-33. [Pubmed Abstract]

Shachaf CM, Perez OD, Youssef S, Fan AC, Elchuri S, Goldstein MJ, Shirer AE, Sharpe O, Chen J, Mitchell DJ, Chang M, Nolan GP, Steinman L, Felsher DW.  Inhibition of HMGcoA reductase by atorvastatin prevents and reverses MYC-induced lymphomagenesis.  Blood. 2007 Oct 1;110(7):2674-84. [Pubmed Abstract]

Giuriato S, Ryeom S, Fan AC, Bachireddy P, Lynch RC, Rioth MJ, van Riggelen J, Kopelman AM, Passegue E, Tang F, Folkman J, Felsher DW. Sustained regression of tumors upon MYC inactivation requires p53 or thrombospondin-1 to reverse the angiogenic switch. Proc Natl Acad Sci U S A. 2006 Oct 31;103(44):16266-71. [Pubmed Abstract]

Arvanitis C, Felsher DW. Conditional transgenic models define how MYC initiates and maintains tumorigenesis. Semin Cancer Biol. 2006 Aug;16(4):313-7. Review. [Pubmed Abstract]

Felsher DW. Tumor dormancy: death and resurrection of cancer as seen through transgenic mouse models. Cell Cycle. 2006 Aug;5(16):1808-11. Review. [Pubmed Abstract]

Weng AP, Millholland JM, Yashiro-Ohtani Y, Arcangeli ML, Lau A, Wai C, Del Bianco C, Rodriguez CG, Sai H, Tobias J, Li Y, Wolfe MS, Shachaf C, Felsher D, Blacklow SC, Pear WS, Aster JC. c-Myc is an important direct target of Notch1 in T-cell acute lymphoblastic leukemia/lymphoma. Genes Dev. 2006 Aug 1;20(15):2096-109.

Ray S, Atkuri KR, Deb-Basu D, Adler AS, Chang HY, Herzenberg LA, Felsher DW.
MYC Can Induce DNA Breaks In vivo and In vitro Independent of Reactive Oxygen Species. Cancer Res. 2006 Jul 1;66(13):6598-6605. [Pubmed Abstract]

Deb-Basu D, Karlsson A, Li Q, Dang CV, Felsher DW. MYC Can Enforce Cell Cycle Transit From G(1) To S and G(2) To S, But Not Mitotic Cellular Division, Independent of p27-Mediated Inihibition of Cyclin E/CDK2. Cell Cycle. 2006 Jun 15;5(12). [Pubmed Abstract]

Deb-Basu D, Aleem E, Kaldis P, Felsher D.  CDK2 Is Required By MYC To Induce Apoptosis.  Cell Cycle. 2006 Jun 15;5(12). [Pubmed Abstract]

Kwon H, Ogle L, Benitez B, Bohuslav J, Montano M, Felsher DW, Greene WC. Lethal cutaneous disease in transgenic mice conditionally expressing type I human T cell leukemia virus Tax. J Biol Chem. 2005 Oct 21;280(42):35713-22. Epub 2005 Aug 16. [Pubmed Abstract]

Sander S, Bullinger L, Karlsson A, Giuriato S, Hernandez-Boussard T, Felsher DW, Pollack JR. Comparative genomic hybridization on mouse cDNA microarrays and its application to a murine lymphoma model. Oncogene. 2005 Sep 8;24(40):6101-7. [Pubmed Abstract]

Arvanitis C, Felsher DW. Conditionally MYC: insights from novel transgenic models. Cancer Lett. 2005 Aug 26;226(2):95-9. Review. [Pubmed Abstract]

Beverly LJ, Felsher DW, Capobianco AJ. Suppression of p53 by Notch in lymphomagenesis: implications for initiation and regression. Cancer Res. 2005 Aug 15;65(16):7159-68. [Pubmed Abstract]

Shachaf CM, Felsher DW. Rehabilitation of cancer through oncogene inactivation. Trends Mol Med. 2005 Jul;11(7):316-21. Review. [Pubmed Abstract]

Bachireddy P, Bendapudi PK, Felsher DW. Getting at MYC through RAS. Clin Cancer Res. 2005 Jun 15;11(12):4278-81. Review. [Pubmed Abstract]

Shachaf CM, Felsher DW. Tumor dormancy and MYC inactivation: pushing cancer to the brink of normalcy. Cancer Res. 2005 Jun 1;65(11):4471-4. Review. [Pubmed Abstract]

Beer S, Zetterberg A, Ihrie RA, McTaggart RA, Yang Q, Bradon N, Arvanitis C, Attardi LD, Feng S, Ruebner B, Cardiff RD, Felsher DW. Developmental Context Determines Latency of MYC-Induced Tumorigenesis. PLoS Biol. 2004 Sep 28;2(11). [Pubmed Abstract]

Baron BW, Anastasi J, Montag A, Huo D, Baron RM, Karrison T, Thirman MJ, Subudhi SK, Chin RK, Felsher DW, Fu YX, McKeithan TW, Baron JM. The human BCL6 transgene promotes the development of lymphomas in the mouse. Proc Natl Acad Sci U S A. 2004 Sep 28;101(39):14198-203. [Pubmed Abstract]

Yang Y, Contag CH, Felsher D, Shachaf CM, Cao Y, Herzenberg LA, Tung JW. The E47 transcription factor negatively regulates CD5 expression during thymocyte development. Proc Natl Acad Sci U S A. 2004 Mar 16;101(11):3898- 902.

Felsher, D. W. Reversibility of oncogene induced cancer. Current Opinion Genetics and Development. 14:37-42, 2004.

Giuriato S, Rabin K, Fan AC, Shachaf CM, Felsher DW. Conditional animal models: a strategy to define when oncogenes will be effective targets to treat cancer. Semin Cancer Biol. 2004 Feb;14(1):3-11. [PubMed Abstract]

Felsher DW. Related Articles, Links Oncogenes as therapeutic targets. Semin Cancer Biol. 2004 Feb;14(1):1.

Felsher DW, Bradon N. Pharmacological inactivation of MYC for the treatment of cancer. Drug News Perspect. 2003 Jul-Aug;16(6):370-4. Review. [PubMed Abstract ]

Karlsson A, Deb-Basu D, Cherry A, Turner S, Ford J, Felsher DW. Defective double-strand DNA break repair and chromosomal translocations by MYC overexpression. Proc Natl Acad Sci U S A. 2003 Aug 19;100(17):9974-9. [Full Text]

Giuriato S, Felsher DW. How cancers escape their oncogene habit. Cell Cycle. 2003 Jul-Aug;2(4):329-32. [PubMed Abstract]

Felsher DW. Cancer revoked: oncogenes as therapeutic targets. Nat Rev Cancer. 2003 May;3(5):375-80. Review. [PubMed Abstract]

Karlsson A, Giuriato S, Tang F, Fung-Weier J, Levan G, Felsher DW. Genomically complex lymphomas undergo sustained tumor regression upon MYC inactivation unless they acquire novel chromosomal translocations. Blood. 2003 Apr 1;101(7):2797-803. [PubMed Abstract]

Johansen LM, Iwama A, Lodie TA, Sasaki K, Felsher DW, Golub TR, Tenen DG. c-Myc is a critical target for c/EBPalpha in granulopoiesis. Mol Cell Biol. 2001; 21(11):3789-806. [Full Text]

Felsher DW, Zetterberg A, Zhu J, Tlsty T, Bishop JM. Overexpression of MYC causes p53-dependent G2 arrest of normal fibroblasts. Proc Natl Acad Sci U S A. 2000 Sep 12;97(19):10544-8. [Full Text]

Felsher DW, Bishop JM. Transient excess of MYC activity can elicit genomic instability and tumorigenesis. Proc Natl Acad Sci U S A. 1999 Mar 30;96(7):3940-4. [Full Text]

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