Synthetic lethality is an efficient mechanism-based approach to selectively target DNA repair defects. ERCC1 deficiency is frequently found in non-small cell lung cancers, making this DNA repair protein an attractive target for exploiting synthetic lethal approaches in this disease. Using unbiased proteomic and metabolic high-throughput profiling on a unique in-house generated isogenic model of ERCC1 deficiency, we found marked metabolic rewiring of ERCC1-deficient populations, including decreased levels of the metabolite NAD+ and reduced expression of the rate-limiting NAD+ biosynthetic enzyme nicotinamide phosphoribosyltransferase (NAMPT). We further evidenced reduced NAMPT expression in NSCLC samples with low levels of ERCC1. These metabolic alterations were a primary effect of ERCC1 deficiency, and caused selective exquisite sensitivity to small molecule NAMPT inhibitors, both in vitro — ERCC1-deficient cells being approximately 1000 times more sensitive — and in vivo. Using transmission electronic microscopy and functional metabolic studies, we found that ERCC1-deficient cells harbor mitochondrial defects. We propose a model where NAD+ acts as a regulator of ERCC1-deficient NSCLC fitness. These findings open therapeutic opportunities that exploit a yet undescribed nuclear — mitochondrial synthetic lethal relationship in cancer cells, and highlight the potential for targeting DNA repair/metabolic crosstalks for cancer therapy.
Mehdi Touat, Tony Sourisseau, Nicolas Dorvault, Roman M. Chabanon, Marlène Garrido, Daphné Morel, Dragomir B. Krastev, Ludovic Bigot, Julien Adam, Jessica Frankum, Sylvère Durand, Clement Pontoizeau, Sylvie Souquère, Mei-Shiue Kuo, Sylvie Sauvaigo, Faraz Mardakheh, Alain Sarasin, Ken A. Olaussen, Luc Friboulet, Frédéric Bouillaud, Gérard Pierron, Alan Ashworth, Anne Lombès, Christopher J. Lord, Jean-Charles Soria, Sophie Postel-Vinay
Immune evasion and the suppression of anti-tumor responses during cancer progression are considered hallmarks of cancer and are typically attributed to tumor-derived factors. Although the molecular basis for the crosstalk between tumor and immune cells is an area of active investigation, whether host-specific germline variants can dictate immunosuppressive mechanisms has remained a challenge to address. A commonly occurring germline mutation (c.1162G>A/rs351855 G/A) in the FGFR4 (CD334) gene enhances STAT3 signaling and is associated with poor prognosis and accelerated progression of multiple cancer types. Here, using rs351855 single nucleotide polymorphism (SNP) knock-in transgenic mice and Fgfr4 knockout mice, we reveal the genotype-specific gain of immunological function of suppressing the CD8/CD4+FOXP3+CD25+ve regulatory T cell ratio in vivo. Furthermore, using knock-in transgenic mouse models for lung and breast cancers, we establish the host-specific tumor-extrinsic functions of STAT3-enhancing germline variants in impeding the tumor infiltration of CD8 T cells. Thus, STAT3-enhancing germline receptor variants contribute to immune evasion through their pleiotropic functions in immune cells.
Daniel Kogan, Alexander Grabner, Christopher Yanucil, Christian Faul, Vijay Kumar Ulaganathan
Myc activation is a primary oncogenic event in many human cancers; however, these transcription factors are difficult to inhibit pharmacologically, suggesting that Myc-dependent downstream effectors may be more tractable therapeutic targets. Here we show that Myc overexpression induces endoplasmic reticulum (ER) stress and engages the IRE1α-XBP1 pathway through multiple molecular mechanisms in a variety of c-Myc- and N-Myc-dependent cancers. In particular, Myc-overexpressing cells require IRE1α-XBP1 signaling for sustained growth and survival in vitro and in vivo, dependent on elevated stearoyl-CoA-desaturase 1 (SCD1) activity. Pharmacological and genetic XBP1 inhibition induces Myc-dependent apoptosis, which is alleviated by exogenous unsaturated fatty acids. Of note, SCD1 inhibition phenocopies IRE1α RNase activity suppression in vivo. Furthermore, IRE1α inhibition enhances the cytotoxic effects of standard chemotherapy drugs used to treat c-Myc-overexpressing Burkitt’s lymphoma, suggesting that inhibiting the IRE1α-XBP1 pathway is a useful general strategy for treatment of Myc-driven cancers.
Hong Xie, Chih-Hang Anthony Tang, Jun H. Song, Anthony Mancuso, Juan R. Del Valle, Jin Cao, Yan Xiang, Chi V. Dang, Roy Lan, Danielle J. Sanchez, Brian Keith, Chih-Chi Andrew Hu, M. Celeste Simon
Aberrant activation of MAPK signaling leads to activation of oncogenic transcriptomes. How MAPK signaling is coupled with transcriptional response in cancer is not fully understood. In gastrointestinal stromal tumor and melanoma, both with oncogenic MAPK activation, we find that ETV1 and other Pea3-ETS transcription factors are critical nuclear effectors of MAPK signaling that are regulated through protein stability. Expression of stabilized Pea3-ETS factors can partially rescue the MAPK transcriptome and cell viability after MAPK inhibition. To identify players involved in this process, we performed a pooled genome-wide RNAi screen using a novel fluorescence-based ETV1 protein stability sensor, and identified COP1, DET1, DDB1, UBE3C, PSMD4, and COP9 signalosome members. COP1 and DET1 loss led to decoupling between MAPK signaling and downstream transcriptional response, where MAPK inhibition failed to destabilize Pea3 factors and fully inhibit the MAPK transcriptome, thus resulting in decreased sensitivity to MAPK pathway inhibitors. We identified multiple COP1 and DET1 mutations in human tumors that were defective in degradation of Pea3-ETS factors. Two melanoma patients had de novo DET1 mutations arising after vemurafenib treatment. These observations indicate that MAPK signaling-dependent regulation of Pea3-ETS protein stability is a key signaling node in oncogenesis and therapeutic resistance to MAPK pathway inhibition.
Yuanyuan Xie, Zhen Cao, Elissa W.P. Wong, Youxin Guan, Wenfu Ma, Jenny Q. Zhang, Edward G. Walczak, Devan Murphy, Leili Ran, Inna Sirota, Shangqian Wang, Shipra Shukla, Dong Gao, Simon R.V. Knott, Kenneth Chang, Justin Leu, John Wongvipat, Cristina R. Antonescu, Gregory Hannon, Ping Chi, Yu Chen
T cells specific for neoantigens encoded by mutated genes in cancers are increasingly recognized as mediators of tumor destruction after immune checkpoint inhibitor therapy or adoptive cell transfer. Unfortunately, most neoantigens result from random mutations and are patient specific, and some cancers contain few mutations to serve as potential antigens. We describe a patient with stage IV acral melanoma who obtained a complete response following adoptive transfer of tumor infiltrating lymphocytes (TIL). Tumor exome sequencing surprisingly revealed less than 30 somatic mutations, including oncogenic BRAF V600E. Analysis of the specificity of TIL identified rare CD4 T cells specific for BRAFV600E and diverse CD8 T cells reactive to non-mutated self-antigens. These specificities increased in blood after TIL transfer and persisted long term suggesting they contributed to the effective antitumor immune response. Gene transfer of the BRAFV600E-specific T cell receptor (TCR) conferred recognition of class II MHC positive cells expressing the BRAF mutation. Therapy with TCR engineered BRAFV600E-specific CD4+ T cells may have direct antitumor effects and augment CD8+ T cell responses to self and/or mutated tumor antigens in patients with BRAF mutated cancers.
Joshua R. Veatch, Sylvia M. Lee, Matthew Fitzgibbon, I-Ting Chow, Brenda Jesernig, Thomas Schmitt, Ying Ying Kong, Julia Kargl, A. McGarry Houghton, John A. Thompson, Martin McIntosh, William W. Kwok, Stanley R. Riddell
Patients with myeloproliferative neoplasms (MPNs) frequently progress to bone marrow failure or acute myeloid leukemia (AML), and mutations in epigenetic regulators such as the metabolic enzyme isocitrate dehydrogenase (IDH) are associated with poor outcomes. Here, we showed that combined expression of Jak2V617F and mutant IDH1R132H or Idh2R140Q induces MPN progression, alters stem/progenitor cell function, and impairs differentiation in mice. Jak2V617F Idh2R140Q–mutant MPNs were sensitive to small-molecule inhibition of IDH. Combined inhibition of JAK2 and IDH2 normalized the stem and progenitor cell compartments in the murine model and reduced disease burden to a greater extent than was seen with JAK inhibition alone. In addition, combined JAK2 and IDH2 inhibitor treatment also reversed aberrant gene expression in MPN stem cells and reversed the metabolite perturbations induced by concurrent JAK2 and IDH2 mutations. Combined JAK2 and IDH2 inhibitor therapy also showed cooperative efficacy in cells from MPN patients with both JAK2mut and IDH2mut mutations. Taken together, these data suggest that combined JAK and IDH inhibition may offer a therapeutic advantage in this high-risk MPN subtype.
Anna Sophia McKenney, Allison N. Lau, Amritha Varshini Hanasoge Somasundara, Barbara Spitzer, Andrew M. Intlekofer, Jihae Ahn, Kaitlyn Shank, Franck T. Rapaport, Minal A. Patel, Efthymia Papalexi, Alan H. Shih, April Chiu, Elizaveta Freinkman, Esra A. Akbay, Mya Steadman, Raj Nagaraja, Katharine Yen, Julie Teruya-Feldstein, Kwok-Kin Wong, Raajit Rampal, Matthew G. Vander Heiden, Craig B. Thompson, Ross L. Levine
The endothelial tyrosine kinase receptor Tie1 remains poorly characterized, largely owing to its orphan receptor status. Global Tie1 inactivation causes late embryonic lethality, thereby reflecting its importance during development. Tie1 also plays pivotal roles during pathologies such as atherosclerosis and tumorigenesis. In order to study the contribution of Tie1 to tumor progression and metastasis, we conditionally deleted Tie1 in endothelial cells at different stages of tumor growth and metastatic dissemination. Tie1 deletion during primary tumor growth in mice led to a decrease in microvessel density and an increase in mural cell coverage with improved vessel perfusion. Reduced angiogenesis and enhanced vascular normalization resulted in a progressive increase of intratumoral necrosis that caused a growth delay only at later stages of tumor progression. Concomitantly, surgical removal of the primary tumor decreased the number of circulating tumor cells, reduced metastasis, and prolonged overall survival. Additionally, Tie1 deletion in experimental murine metastasis models prevented extravasation of tumor cells into the lungs and reduced metastatic foci. Taken together, the data support Tie1 as a therapeutic target by defining its regulatory functions during angiogenesis and vascular abnormalization and identifying its role during metastasis.
Silvia La Porta, Lise Roth, Mahak Singhal, Carolin Mogler, Carleen Spegg, Benjamin Schieb, Xianghu Qu, Ralf H. Adams, H. Scott Baldwin, Soniya Savant, Hellmut G. Augustin
The prognosis for bladder cancer patients with lymph node (LN) metastasis is dismal and only minimally improved by current treatment modalities. Elucidation of the molecular mechanisms that underlie LN metastasis may provide clinical therapeutic strategies for LN-metastatic bladder cancer. Here, we report that a long noncoding RNA LINC00958, which we have termed bladder cancer–associated transcript 2 (BLACAT2), was markedly upregulated in LN-metastatic bladder cancer and correlated with LN metastasis. Overexpression of BLACAT2 promoted bladder cancer–associated lymphangiogenesis and lymphatic metastasis in both cultured bladder cancer cell lines and mouse models. Furthermore, we demonstrate that BLACAT2 epigenetically upregulated VEGF-C expression by directly associating with WDR5, a core subunit of human H3K4 methyltransferase complexes. Importantly, administration of an anti–VEGF-C antibody inhibited LN metastasis in BLACAT2-overexpressing bladder cancer. Taken together, these findings uncover a molecular mechanism in the lymphatic metastasis of bladder cancer and indicate that BLACAT2 may represent a target for clinical intervention in LN-metastatic bladder cancer.
Wang He, Guangzheng Zhong, Ning Jiang, Bo Wang, Xinxiang Fan, Changhao Chen, Xu Chen, Jian Huang, Tianxin Lin
Blockade of the checkpoint inhibitor programmed death 1 (PD1) has demonstrated remarkable success in the clinic for the treatment of cancer; however, a majority of tumors are resistant to anti-PD1 monotherapy. Numerous ongoing clinical combination therapy studies will likely reveal additional therapeutics that complement anti-PD1 blockade. Recent studies found that immunogenic cell death (ICD) improves T cell responses against different tumors, thus indicating that ICD may further augment antitumor immunity elicited by anti-PD1. Here, we observed antitumor activity following combinatorial therapy with anti-PD1 Ab and the cyclin-dependent kinase inhibitor dinaciclib in immunocompetent mouse tumor models. Dinaciclib induced a type I IFN gene signature within the tumor, leading us to hypothesize that dinaciclib potentiates the effects of anti-PD1 by eliciting ICD. Indeed, tumor cells treated with dinaciclib showed the hallmarks of ICD including surface calreticulin expression and release of high mobility group box 1 (HMGB1) and ATP. Mice treated with both anti-PD1 and dinaciclib showed increased T cell infiltration and DC activation within the tumor, indicating that this combination improves the overall quality of the immune response generated. These findings identify a potential mechanism for the observed benefit of combining dinaciclib and anti-PD1, in which dinaciclib induces ICD, thereby converting the tumor cell into an endogenous vaccine and boosting the effects of anti-PD1.
Dewan Md Sakib Hossain, Sarah Javaid, Mingmei Cai, Chunsheng Zhang, Anandi Sawant, Marlene Hinton, Manjiri Sathe, Jeff Grein, Wendy Blumenschein, Elaine M. Pinheiro, Alissa Chackerian
Programmed death–ligand 1 (PD-L1) expression on tumor cells is essential for T cell impairment, and PD-L1 blockade therapy has shown unprecedented durable responses in several clinical studies. Although higher expression of PD-L1 on tumor cells is associated with a better immune response after Ab blockade, some PD-L1–negative patients also respond to this therapy. In the current study, we explored whether PD-L1 on tumor or host cells was essential for anti–PD-L1–mediated therapy in 2 different murine tumor models. Using real-time imaging in whole tumor tissues, we found that anti–PD-L1 Ab accumulates in tumor tissues regardless of the status of PD-L1 expression on tumor cells. We further observed that, while PD-L1 on tumor cells was largely dispensable for the response to checkpoint blockade, PD-L1 in host myeloid cells was essential for this response. Additionally, PD-L1 signaling in defined antigen presenting cells (APCs) negatively regulated and inhibited T cell activation. PD-L1 blockade inside tumors was not sufficient to mediate regression, as limiting T cell trafficking reduced the efficacy of the blockade. Together, these findings demonstrate that PD-L1 expressed in APCs, rather than on tumor cells, plays an essential role in checkpoint blockade therapy, providing an insight into the mechanisms of this therapy.
Haidong Tang, Yong Liang, Robert A. Anders, Janis M. Taube, Xiangyan Qiu, Aditi Mulgaonkar, Xin Liu, Susan M. Harrington, Jingya Guo, Yangchun Xin, Yahong Xiong, Kien Nham, William Silvers, Guiyang Hao, Xiankai Sun, Mingyi Chen, Raquibul Hannan, Jian Qiao, Haidong Dong, Hua Peng, Yang-Xin Fu