Chimeric antigen receptors (CARs) have an antigen-binding domain fused to transmembrane, costimulatory, and CD3ζ domains. Two CARs with regulatory approval include a CD28 or 4-1BB costimulatory domain. While both CARs achieve similar clinical outcomes, biologic differences have become apparent but not completely understood. Therefore, in this study we aimed to identify mechanistic differences between 4-1BB and CD28 costimulation that contribute to the biologic differences between the 2 CARs and could be exploited to enhance CAR T cell function. Using CD19-targeted CAR T cells with 4-1BB we determined that enhancement of T cell function is driven by NF-κB. Comparison to CAR T cells with CD28 also revealed that 4-1BB is associated with more antiapoptotic proteins and dependence on persistence for B cell killing. While TNF receptor–associated factor 2 (TRAF2) has been presupposed to be required for 4-1BB costimulation in CAR T cells, we determined that TRAF1 and TRAF3 are also critical. We observed that TRAFs impacted CAR T viability and proliferation, as well as cytotoxicity and/or cytokines, in part by regulating NF-κB. Our study demonstrates how 4-1BB costimulation in CAR T cells impacts antitumor eradication and clinical outcomes and has implications for enhanced CAR design.
Gongbo Li, Justin C. Boucher, Hiroshi Kotani, Kyungho Park, Yongliang Zhang, Bishwas Shrestha, Xuefeng Wang, Lawrence Guan, Nolan Beatty, Daniel Abate-Daga, Marco L. Davila
Sarcomas are still unsolved therapeutic challenges. Cancer stem cells are believed to contribute to sarcoma development, but lack of specific markers prevents their characterization and targeting. Here, we show that calpain-6 expression is associated with cancer stem cell features. In mouse models of bone sarcoma, calpain-6–expressing cells have unique tumor-initiating and metastatic capacities. Calpain-6 levels are especially high in tumors that have been successfully propagated in mouse to establish patient-derived xenografts. We found that calpain-6 levels are increased by hypoxia in vitro and calpain-6 is detected within hypoxic areas in tumors. Furthermore, calpain-6 expression depends on the stem cell transcription network that involves Oct4, Nanog, and Sox2 and is activated by hypoxia. Calpain-6 knockdown blocks tumor development in mouse and induces depletion of the cancer stem cell population. Data from transcriptomic analyses reveal that calpain-6 expression in sarcomas inversely correlates with senescence markers. Calpain-6 knockdown suppresses hypoxia-dependent prevention of senescence entry and also promotion of autophagic flux. Together, our results demonstrate that calpain-6 identifies sarcoma cells with stem-like properties and is a mediator of hypoxia to prevent senescence, promote autophagy, and maintain the tumor-initiating cell population. These findings open what we believe is a novel therapeutic avenue for targeting sarcoma stem cells.
Caroline Andrique, Laetitia Morardet, Laetitia K. Linares, Madi Y. Cissé, Candice Merle, Frédéric Chibon, Sylvain Provot, Eric Haÿ, Hang-Korng Ea, Martine Cohen-Solal, Dominique Modrowski
While it has been recognized that human papillomavirus–associated (HPV-associated) oropharyngeal cancer (OPC) portends an improved prognosis, distinct patterns of disease recurrence have emerged. Molecular characterization of this subset of HPV patients remains unexplored. We evaluated 52 metastatic HPV+ OPC patients from our institution and paired massively parallel sequencing data with clinical parameters and survival outcomes in 81% of patients. Genomic data were then compared with 2 molecularly defined, curable HPV+ cohorts. Metastatic HPV+ OPC patients with pulmonary-only metastases demonstrated worse outcomes. Nonexclusive somatic alterations in KMT2D and PIK3CA were most frequent, with PRKDC alterations occurring at higher frequency when compared with all sequenced HPV+ OPC patients. PI3K pathway alterations were associated with improved outcomes among metastatic HPV+ OPC patients. We demonstrate subtle differences in the mutational landscape between curable and metastatic HPV+ OPC populations, with a trend towards more frequent DNA repair protein alterations in the latter. We demonstrate improved outcomes when PI3K pathway alterations are present in these patients. We provide molecular insights for this important HPV+ subgroup that have significant therapeutic implications.
Glenn J. Hanna, Alec Kacew, Nicole G. Chau, Priyanka Shivdasani, Jochen H. Lorch, Ravindra Uppaluri, Robert I. Haddad, Laura E. MacConaill
Although initially responsive to androgen signaling inhibitors (ASIs), metastatic castration-resistant prostate cancer (mCRPC) inevitably develops and is incurable. In addition to adenocarcinoma (adeno), neuroendocrine prostate cancer (NEPC) emerges to confer ASI resistance. We have previously combined laser capture microdissection and phage antibody display library selection on human cancer specimens and identified novel internalizing antibodies binding to tumor cells residing in their tissue microenvironment. We identified the target antigen for one of these antibodies as CD46, a multifunctional protein that is best known for negatively regulating the innate immune system. CD46 is overexpressed in primary tumor tissue and CRPC (localized and metastatic; adeno and NEPC), but expressed at low levels on normal tissues except for placental trophoblasts and prostate epithelium. Abiraterone- and enzalutamide-treated mCRPC cells upregulate cell surface CD46 expression. Genomic analysis showed that the CD46 gene is gained in 45% abiraterone-resistant mCRPC patients. We conjugated a tubulin inhibitor to our macropinocytosing anti-CD46 antibody and showed that the resulting antibody-drug conjugate (ADC) potently and selectively kills both adeno and NEPC cell lines in vitro (sub-nM EC50) but not normal cells. CD46 ADC regressed and eliminated an mCRPC cell line xenograft in vivo in both subcutaneous and intrafemoral models. Exploratory toxicology studies of the CD46 ADC in non-human primates demonstrated an acceptable safety profile. Thus, CD46 is an excellent target for antibody-based therapy development, which has potential to be applicable to both adenocarcinoma and neuroendocrine types of mCRPC that are resistant to current treatment.
Yang Su, Yue Liu, Christopher R. Behrens, Scott Bidlingmaier, Nam-Kyung Lee, Rahul Aggarwal, Daniel W. Sherbenou, Alma L. Burlingame, Byron C. Hann, Jeffry P. Simko, Gayatri Premasekharan, Pamela L. Paris, Marc A. Shuman, Youngho Seo, Eric J. Small, Bin Liu
Osteosarcoma (OS), a malignant tumor of bone, kills through aggressive metastatic spread almost exclusively to the lung. Mechanisms driving this tropism for lung tissue remain unknown, though likely invoke specific interactions between tumor cells and other cells within the lung metastatic niche. Aberrant overexpression of ΔNp63 in OS cells directly drives production of IL-6 and CXCL8. All these factors were expressed at higher levels in OS lung metastases than in matched primary tumors from the same patients. Expression in cell lines correlated strongly with lung colonization efficiency in murine xenograft models. Lentivirus-mediated expression endowed poorly metastatic OS cells with increased metastatic capacity. Disruption of IL-6 and CXCL8 signaling using genetic or pharmaceutical inhibitors had minimal effects on tumor cell proliferation in vitro or in vivo, but combination treatment inhibited metastasis across multiple models of metastatic OS. Strong interactions occurred between OS cells and both primary bronchial epithelial cells and bronchial smooth muscle cells that drove feed-forward amplification of IL-6 and CXCL8 production. These results identify IL-6 and CXCL8 as primary mediators of OS lung tropism and suggest pleiotropic, redundant mechanisms by which they might effect metastasis. Combination therapy studies demonstrate proof of concept for targeting these tumor-lung interactions to affect metastatic disease.
Amy C. Gross, Hakan Cam, Doris A. Phelps, Amanda J. Saraf, Hemant K. Bid, Maren Cam, Cheryl A. London, Sarah A. Winget, Michael A. Arnold, Laura Brandolini, Xiaokui Mo, John M. Hinckley, Peter J. Houghton, Ryan D. Roberts
Although a subset of clear cell renal cell carcinoma (ccRCC) patients respond to immune checkpoint blockade (ICB), predictors of response remain uncertain. We investigated whether abnormal expression of endogenous retroviruses (ERVs) in tumors is associated with local immune checkpoint activation (ICA) and response to ICB. Twenty potentially immunogenic ERVs (πERVs) were identified in ccRCC in The Cancer Genome Atlas data set, and tumors were stratified into 3 groups based on their expression levels. πERV-high ccRCC tumors showed increased immune infiltration, checkpoint pathway upregulation, and higher CD8+ T cell fraction in infiltrating leukocytes compared with πERV-low ccRCC tumors. Similar results were observed in ER+/HER2− breast, colon, and head and neck squamous cell cancers. ERV expression correlated with expression of genes associated with histone methylation and chromatin regulation, and πERV-high ccRCC was enriched in BAP1 mutant tumors. ERV3-2 expression correlated with ICA in 11 solid cancers, including the 4 named above. In a small retrospective cohort of 24 metastatic ccRCC patients treated with single-agent PD-1/PD-L1 blockade, ERV3-2 expression in tumors was significantly higher in responders compared with nonresponders. Thus, abnormal expression of πERVs is associated with ICA in several solid cancers, including ccRCC, and ERV3-2 expression is associated with response to ICB in ccRCC.
Anshuman Panda, Aguirre A. de Cubas, Mark Stein, Gregory Riedlinger, Joshua Kra, Tina Mayer, Christof C. Smith, Benjamin G. Vincent, Jonathan S. Serody, Kathryn E. Beckermann, Shridar Ganesan, Gyan Bhanot, W. Kimryn Rathmell
Metastatic medullary thyroid cancer (MTC) is incurable and FDA-approved kinase inhibitors that include oncogenic RET as a target do not result in complete responses. Association studies of human MTCs and murine models suggest that the CDK/RB pathway may be an alternative target. The objective of this study was to determine if CDKs represent therapeutic targets for MTC and to define mechanisms of activity. Using human MTC cells that are either sensitive or resistant to vandetanib, we demonstrate that palbociclib (CDK4/6 inhibitor) is not cytotoxic to MTC cells but that they are highly sensitive to dinaciclib (CDK1/2/5/9 inhibitor) accompanied by reduced CDK9 and RET protein and mRNA levels. CDK9 protein was highly expressed in 83 of 83 human MTCs and array–comparative genomic hybridization had copy number gain in 11 of 30 tumors. RNA sequencing demonstrated that RNA polymerase II–dependent transcription was markedly reduced by dinaciclib. The CDK7 inhibitor THZ1 also demonstrated high potency and reduced RET and CDK9 levels. ChIP-sequencing using H3K27Ac antibody identified a superenhancer in intron 1 of RET. Finally, combined inhibition of dinaciclib with a RET kinase inhibitor was synergistic. In summary, we have identified what we believe is a novel mechanism of RET transcription regulation that potentially can be exploited to improve RET therapeutic targeting.
Anisley Valenciaga, Motoyasu Saji, Lianbo Yu, Xiaoli Zhang, Ceimoani Bumrah, Ayse S. Yilmaz, Christina M. Knippler, Wayne Miles, Thomas J. Giordano, Gilbert J. Cote, Matthew D. Ringel
Evofosfamide (TH-302) is a clinical-stage hypoxia-activated prodrug of a DNA-crosslinking nitrogen mustard that has potential utility for human papillomavirus (HPV) negative head and neck squamous cell carcinoma (HNSCC), in which tumor hypoxia limits treatment outcome. We report the preclinical efficacy, target engagement, preliminary predictive biomarkers and initial clinical activity of evofosfamide for HPV-negative HNSCC. Evofosfamide was assessed in 22 genomically characterized cell lines and 7 cell line–derived xenograft (CDX), patient-derived xenograft (PDX), orthotopic, and syngeneic tumor models. Biomarker analysis used RNA sequencing, whole-exome sequencing, and whole-genome CRISPR knockout screens. Five advanced/metastatic HNSCC patients received evofosfamide monotherapy (480 mg/m2 qw × 3 each month) in a phase 2 study. Evofosfamide was potent and highly selective for hypoxic HNSCC cells. Proliferative rate was a predominant evofosfamide sensitivity determinant and a proliferation metagene correlated with activity in CDX models. Evofosfamide showed efficacy as monotherapy and with radiotherapy in PDX models, augmented CTLA-4 blockade in syngeneic tumors, and reduced hypoxia in nodes disseminated from an orthotopic model. Of 5 advanced HNSCC patients treated with evofosfamide, 2 showed partial responses while 3 had stable disease. In conclusion, evofosfamide shows promising efficacy in aggressive HPV-negative HNSCC, with predictive biomarkers in development to support further clinical evaluation in this indication.
Stephen M.F. Jamieson, Peter Tsai, Maria K. Kondratyev, Pratha Budhani, Arthur Liu, Neil N. Senzer, E. Gabriela Chiorean, Shadia I. Jalal, John J. Nemunaitis, Dennis Kee, Avik Shome, Way W. Wong, Dan Li, Nooriyah Poonawala-Lohani, Purvi M. Kakadia, Nicholas S. Knowlton, Courtney R.H. Lynch, Cho R. Hong, Tet Woo Lee, Reidar A. Grénman, Laura Caporiccio, Trevor D. McKee, Mark Zaidi, Sehrish Butt, Andrew M.J. Macann, Nicholas P. McIvor, John M. Chaplin, Kevin O. Hicks, Stefan K. Bohlander, Bradly G. Wouters, Charles P. Hart, Cristin G. Print, William R. Wilson, Michael A. Curran, Francis W. Hunter
BACKGROUND. There is currently no clinical distinction between different TP53 mutations, despite increasing evidence that not all mutations have equally deleterious effects on the activity of the encoded tumor suppressor protein p53. The objective of this study was to determine whether these biological differences have clinical significance. METHODS. This retrospective cohort analysis included 2,074 patients with sporadic TP53 mutations (403 unique mutations) and 1,049 germline TP53 mutation carriers (188 unique mutations). Survival was projected by stratifying patients according to their p53 mutant–specific residual transcriptional activity scores. RESULTS. Pan-cancer survival analyses revealed a strong association between increased mutant p53 residual activity and improved survival in males with glioma and gastric adenocarcinoma (P = 0.002 and P = 0.02) that was not present in the female cohorts (P = 0.16 and P = 0.50). Male glioma and gastric cancer patients with TP53 mutations resulting in >5% transcriptional activity had 3.1-fold (95% CI, 2.4–3.8; P = 0.002; multivariate analysis hazard ratio [HR]) and 4.6-fold (95% CI, 3.7–5.6; P = 0.001; multivariate analysis HR) lower risk of death as compared with patients harboring inactive (0% activity) p53 mutants. The correlation between mutant p53 residual activity with survival was recapitulated in the dataset of germline TP53 mutation carriers (HR = 3.0, 95% CI, 2.7–3.4, P < 0.001 [females]; HR = 2.2, 95% CI, 1.8–2.6, P < 0.001 [males]), where brain and gastric tumors were more common among males (P < 0.001 and P = 0.001, respectively). CONCLUSION. The retention of mutant p53 transcriptional activity prognosticates superior survival for men with glioma and gastric adenocarcinoma harboring sporadic TP53 mutations. Among germline TP53 mutation carriers, increased residual transcriptional activity is correlated with prolonged lifetime cancer survival and delayed tumor onset, and males are more prone to develop brain and gastric tumors. FUNDING. Canadian Institutes of Health Research (no. 148556).
Nicholas W. Fischer, Aaron Prodeus, Jean Gariépy
With more than 150,000 deaths per year in the US alone, lung cancer has the highest number of deaths for any cancer. These poor outcomes reflect a lack of treatment for the most common form of lung cancer, non–small cell lung carcinoma (NSCLC). Lung adenocarcinoma (ADC) is the most prevalent subtype of NSCLC, with the main oncogenic drivers being KRAS and epidermal growth factor receptor (EGFR). Whereas EGFR blockade has led to some success in lung ADC, effective KRAS inhibition is lacking. KRAS-mutant ADCs are characterized by high levels of gel-forming mucin expression, with the highest mucin levels corresponding to worse prognoses. Despite these well-recognized associations, little is known about roles for individual gel-forming mucins in ADC development causatively. We hypothesized that MUC5AC/Muc5ac, a mucin gene known to be commonly expressed in NSCLC, is crucial in KRAS/Kras-driven lung ADC. We found that MUC5AC was a significant determinant of poor prognosis, especially in patients with KRAS-mutant tumors. In addition, by using mice with lung ADC induced chemically with urethane or transgenically by mutant-Kras expression, we observed significantly reduced tumor development in animals lacking Muc5ac compared with controls. Collectively, these results provide strong support for MUC5AC as a potential therapeutic target for lung ADC, a disease with few effective treatments.
Alison K. Bauer, Misha Umer, Vanessa L. Richardson, Amber M. Cumpian, Anna Q. Harder, Nasim Khosravi, Zoulikha Azzegagh, Naoko M. Hara, Camille Ehre, Maedeh Mohebnasab, Mauricio S. Caetano, Daniel T. Merrick, Adrie van Bokhoven, Ignacio I. Wistuba, Humam Kadara, Burton F. Dickey, Kalpana Velmurugan, Patrick R. Mann, Xian Lu, Anna E. Barón, Christopher M. Evans, Seyed Javad Moghaddam
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