Excellence in Science

Tumor Microenvironment Remodeling Enables Bypass of Oncogenic KRAS Dependency in Pancreatic Cancer

Oncogenic KRAS (KRAS*) is a key tumor maintenance gene in pancreatic ductal adenocarcinoma (PDAC), motivating pharmacologic targeting of KRAS* and its effectors. Here, we explored mechanisms involving the tumor microenvironment (TME) as a potential basis for resistance to targeting KRAS*. Using the inducible Kras^G12D;Trp53^-/- PDAC mouse model, gain-of-function screens of epigenetic regulators identified HDAC5 as the top hit enabling KRAS* independent tumor growth. HDAC5-driven escaper tumors showed a prominent neutrophil-to-macrophage switch relative to KRAS*-driven tumors. Mechanistically, HDAC5 represses Socs3, a negative regulator of chemokine CCL2, resulting in increased CCL2, which recruits CCR2⁺ macrophages. Correspondingly, enforced Ccl2 promotes macrophage recruitment into the TME and enables tumor recurrence following KRAS* extinction. These tumor-associated macrophages in turn provide cancer cells with trophic support including TGFβ to enable KRAS* bypass in a SMAD4-dependent manner. Our work uncovers a KRAS* resistance mechanism involving immune cell remodeling of the PDAC TME.

SIGNIFICANCE: Although KRAS* is required for PDAC tumor maintenance, tumors can recur following KRAS* extinction. The capacity of PDAC cancer cells to alter the TME myeloid cell composition to support KRAS*-independent tumor growth illuminates novel therapeutic targets that may enhance the effectiveness of therapies targeting KRAS* and its pathway components.

Pingping Hou, Avnish Kapoor, Qiang Zhang, Jiexi Li, Chang-Jiun Wu, Jun Li, Zhengdao Lan, Ming Tang, Xingdi Ma, Jeffrey J. Ackroyd, Raghu Kalluri, Jianhua Zhang, Shan Jiang, Denise J. Spring, Y. Alan Wang, and Ronald A. DePinho

Read more in Cancer Discovery

Selective Inhibition of HDAC3 Targets Synthetic Vulnerabilities and Activates Immune Surveillance in Lymphoma

CREBBP mutations are highly recurrent in B-cell lymphomas and either inactivate its histone acetyltransferase (HAT) domain or truncate the protein. Herein, we show that these two classes of mutations yield different degrees of disruption of the epigenome, with HAT mutations being more severe and associated with inferior clinical outcome. Genes perturbed by CREBBP mutation are direct targets of the BCL6–HDAC3 onco-repressor complex. Accordingly, we show that HDAC3-selective inhibitors reverse CREBBP-mutant aberrant epigenetic programming, resulting in: (i) growth inhibition of lymphoma cells through induction of BCL6 target genes such as CDKN1A and (ii) restoration of immune surveillance due to induction of BCL6-repressed IFN pathway and antigen-presenting genes. By reactivating these genes, exposure to HDAC3 inhibitors restored the ability of tumor-infiltrating lymphocytes to kill DLBCL cells in an MHC class I and II–dependent manner, and synergized with PD-L1 blockade in a syngeneic model in vivo. Hence, HDAC3 inhibition represents a novel mechanism-based immune epigenetic therapy for CREBBP-mutant lymphomas.

SIGNIFICANCE: We have leveraged the molecular characterization of different types of CREBBP mutations to define a rational approach for targeting these mutations through selective inhibition of HDAC3. This represents an attractive therapeutic avenue for targeting synthetic vulnerabilities in CREBBP-mutant cells in tandem with promoting antitumor immunity.

Patrizia Mondello, Saber Tadros, Matt Teater, Lorena Fontan, Aaron Y. Chang, Neeraj Jain, Haopeng Yang, Shailbala Singh, Hsia-Yuan Ying, Chi-Shuen Chu, Man Chun John Ma, Eneda Toska, Stefan Alig, Matthew Durant, Elisa de Stanchina, Sreejoyee Ghosh, Anja Mottok, Loretta Nastoupil, Sattva S. Neelapu, Oliver Weigert, Giorgio Inghirami, José Baselga, Anas Younes, Cassian Yee, Ahmet Dogan, David A. Scheinberg, Robert G. Roeder, Ari M. Melnick, and Michael R. Green

Read more in Cancer Discovery

Proteome Instability Is a Therapeutic Vulnerability in Mismatch Repair-Deficient Cancer

Deficient DNA mismatch repair (dMMR) induces a hypermutator phenotype that can lead to tumorigenesis; however, the functional impact of the high mutation burden resulting from this phenotype remains poorly explored. Here, we demonstrate that dMMR-induced destabilizing mutations lead to proteome instability in dMMR tumors, resulting in an abundance of misfolded protein aggregates. To compensate, dMMR cells utilize a Nedd8-mediated degradation pathway to facilitate clearance of misfolded proteins. Blockade of this Nedd8 clearance pathway with MLN4924 causes accumulation of misfolded protein aggregates, ultimately inducing immunogenic cell death in dMMR cancer cells. To leverage this immunogenic cell death, we combined MLN4924 treatment with PD1 inhibition and found the combination was synergistic, significantly improving efficacy over either treatment alone.

Daniel J. McGrail, Jeannine Garnett, Jun Yin, Hui Dai, David J.H. Shih, Truong Nguyen Anh Lam, Yang Li, Chaoyang Sun, Yongsheng Li, Rosemarie Schmandt, Ji Yuan Wu, Limei Hu, Yulong Liang, Guang Peng, Eric Jonasch, David Menter, Melinda S. Yates, Scott Kopetz, Karen H. Lu, Russell Broaddus, Gordon B. Mills, Nidhi Sahni, and Shiaw-Yih Lin

Read more in Cancer Cell

Pan-Cancer Efficacy of Vemurafenib in BRAF^V600-Mutant Non-Melanoma Cancers

BRAF^V600 mutations occur in a wide range of tumor types, and RAF inhibition has become standard in several of these cancers. Despite this progress, BRAF^V600 mutations have historically been considered a clear demonstration of tumor lineage context–dependent oncogene addiction, based predominantly on the insensitivity to RAF inhibition in colorectal cancer. However, the true broader activity of RAF inhibition pan-cancer remains incompletely understood. To address this, we conducted a multicohort “basket” study of the BRAF inhibitor vemurafenib in non-melanoma BRAF^V600 mutation–positive solid tumors. In total, 172 patients with 26 unique cancer types were treated, achieving an overall response rate of 33% and median duration of response of 13 months. Responses were observed in 13 unique cancer types, including historically treatment-refractory tumor types such as cholangiocarcinoma, sarcoma, glioma, neuroendocrine carcinoma, and salivary gland carcinomas. Collectively, these data demonstrate that single-agent BRAF inhibition has broader clinical activity than previously recognized.

SIGNIFICANCE: These data suggest that BRAF^V600 mutations lead to oncogene addiction and are clinically actionable in a broad range of non-melanoma cancers, including tumor types in which RAF inhibition is not currently considered standard of care.

Vivek Subbiah, Igor Puzanov, Jean-Yves Blay, Ian Chau, A. Craig Lockhart, Noopur S. Raje, Juergen Wolf, José Baselga, Funda Meric-Bernstam, Jason Roszik, Eli L. Diamond, Gregory J. Riely, Eric J. Sherman, Todd Riehl, Bethany Pitcher, and David M. Hyman

Read more in Cancer Discovery

Loss of p53 drives
neuron reprogramming in head and neck cancer

The solid tumour microenvironment includes nerve fibres that arise from the peripheral nervous system. Recent work indicates that newly formed adrenergic nerve fibres promote tumour growth, but the origin of these nerves and the mechanism of their inception are unknown. Here, by comparing the transcriptomes of cancer-associated trigeminal sensory neurons with those of endogenous neurons in mouse models of oral cancer, we identified an adrenergic differentiation signature. We show that loss of TP53 leads to adrenergic transdifferentiation of tumour-associated sensory nerves through loss of the microRNA miR- 34a. Tumour growth was inhibited by sensory denervation or pharmacological blockade of adrenergic receptors, but not by chemical sympathectomy of pre-existing adrenergic nerves. A retrospective analysis of samples from oral cancer revealed that p53 status was associated with nerve density, which was in turn associated with poor clinical outcomes. This crosstalk between cancer cells and neurons represents mechanism by which tumour-associated neurons are reprogrammed towards an adrenergic phenotype that can stimulate tumour progression, and is a potential target for anticancer therapy.

Moran Amit, Hideaki Takahashi, Mihnea Paul Dragomir, Antje Lindemann, Frederico O. Gleber-Netto, Curtis R. Pickering, Simone Anfossi, Abdullah A. Osman, Yu Cai, Rong Wang, Erik Knutsen, Masayoshi Shimizu, Cristina Ivan, Xiayu Rao, Jing Wang, Deborah A. Silverman, Samantha Tam, Mei Zhao, Carlos Caulin, Assaf Zinger, Ennio Tasciotti, Patrick M. Dougherty, Adel El-Naggar, George A. Calin, and  Jeffrey N. Myers

Read more in Nature

Immune profiling of human tumors identifies CD73 as a combinatorial target in glioblastoma

Immune checkpoint therapy with anti- CTLA-4 and anti-PD-1/PD-L1 has revolutionized the treatment of many solid tumors. However, the clinical efficacy of immune checkpoint therapy is limited to a subset of patients with specific tumor types. Multiple clinical trials with combinatorial immune checkpoint strategies are ongoing; however, the mechanistic rationale for tumor-specific targeting of immune checkpoints is elusive. To garner an insight into tumor-specific immunomodulatory targets, we analyzed 94 patients representing five different cancer types, including those that respond relatively well to immune checkpoint therapy and those that do not, such as glioblastoma multiforme, prostate cancer and colorectal cancer. Through mass cytometry and single-cell RNA sequencing, we identified a unique population of CD73^hi macrophages in glioblastoma multiforme that persists after anti-PD-1 treatment. To test if targeting CD73 would be important for a successful combination strategy in glioblastoma multiforme, we performed reverse translational studies using CD73^-/- mice. We found that the absence of CD73 improved survival in a murine model of glioblastoma multiforme treated with anti-CTLA-4 and anti-PD-1. Our data identified CD73 as a specific immunotherapeutic target to improve antitumor immune responses to immune checkpoint therapy in glioblastoma multiforme and demonstrate that comprehensive human and reverse translational studies can be used for rational design of combinatorial immune checkpoint strategies.

Sangeeta Goswami, Thomas Walle, Andrew E. Cornish, Sreyashi Basu, Swetha Anandhan, Irina Fernandez, Luis Vence, Jorge Blando, Hao Zhao, Shalini Singh Yadav, Martina Ott, Ling Y. Kong, Amy B. Heimberger, John de Groot, Boris Sepesi, Michael Overman, Scott Kopetz, James P. Allison, Dana Pe’er, and Padmanee Sharma

Read more in Nature Medicine

Use of CAR-Transduced Natural Killer Cells in CD19-Positive Lymphoid Tumors

BACKGROUND: Anti-CD19 chimeric antigen receptor (CAR) T-cell therapy has shown remarkable clinical efficacy in B-cell cancers. However, CAR T cells can induce substantial toxic effects, and the manufacture of the cells is complex. Natural killer (NK) cells that have been modified to express an anti-CD19 CAR have the potential to overcome these limitations.

METHODS: In this phase 1 and 2 trial, we administered HLA-mismatched anti-CD19 CAR-NK cells derived from cord blood to 11 patients with relapsed or refractory CD19-positive cancers (non-Hodgkin’s lymphoma or chronic lymphocytic leukemia [CLL]). NK cells were transduced with a retroviral vector expressing genes that encode anti-CD19 CAR, interleukin-15, and inducible caspase 9 as a safety switch. The cells were expanded ex vivo and administered in a single infusion at one of three doses (1×10⁵, 1×10⁶, or 1×10⁷ CAR-NK cells per kilogram of body weight) after lymphodepleting chemotherapy.

RESULTS: The administration of CAR-NK cells was not associated with the development of cytokine release syndrome, neurotoxicity, or graft-versus- host disease, and there was no increase in the levels of inflammatory cytokines, including interleukin-6, over baseline. The maximum tolerated dose was not reached. Of the 11 patients who were treated, 8 (73%) had a response; of these patients, 7 (4 with lymphoma and 3 with CLL) had a complete remission, and 1 had remission of the Richter’s transformation component but had persistent CLL. Responses were rapid and seen within 30 days after infusion at all dose levels. The infused CAR-NK cells expanded and persisted at low levels for at least 12 months.

CONCLUSIONS: Among 11 patients with relapsed or refractory CD19-positive cancers, a majority had a response to treatment with CAR-NK cells without the development of major toxic effects. (Funded by the M.D. Anderson Cancer Center CLL and Lymphoma Moonshot and the National Institutes of Health; ClinicalTrials.gov number, NCT03056339.)

Enli Liu, David Marin, Pinaki Banerjee, Homer A. Macapinlac, Philip Thompson, Rafet Basar, Lucila Nassif Kerbauy, Bethany Overman, Peter Thall, Mecit Kaplan, Vandana Nandivada, Indresh Kaur, Ana Nunez Cortes, Kai Cao, May Daher, Chitra Hosing, Evan N. Cohen, Partow Kebriaei, Rohtesh Mehta, Sattva Neelapu, Yago Nieto, Michael Wang, William Wierda, Michael Keating, Richard Champlin, Elizabeth J. Shpall, and Katayoun Rezvani

Read more in The New England Journal of Medicine

Encorafenib, Binimetinib, and Cetuximab in BRAF V600E–Mutated Colorectal Cancer

BACKGROUND: Patients with metastatic colorectal can­cer with the BRAF V600E mutation have a poor prognosis, with a median overall survival of 4 to 6 months after failure of initial therapy. Inhibition of BRAF alone has limited activity because of pathway reactivation through epidermal growth factor receptor signaling.

RESULTS: The median overall survival was 9.0 months in the triplet-therapy group and 5.4 months in the control group (hazard ratio for death, 0.52; 95% confidence in­terval [CI], 0.39 to 0.70; P<0.001). The confirmed response rate was 26% (95% CI, 18 to 35) in the triplet-therapy group and 2% (95% CI, 0 to 7) in the control group (P<0.001). The median overall sur­vival in the doublet-therapy group was 8.4 months (hazard ratio for death vs. control, 0.60; 95% CI, 0.45 to 0.79; P<0.001). Ad­verse events of grade 3 or higher occurred in 58% of patients in the triplet-thera­py group, in 50% in the doublet-therapy group, and in 61% in the control group.

CONCLUSIONS: A combination of encorafenib, cetuximab, and binimetinib resulted in significantly longer overall survival and a higher re­sponse rate than standard therapy in pa­tients with metastatic colorectal cancer with the BRAF V600E mutation. (Funded by Array BioPharma and others; BEA­CON CRC ClinicalTrials.gov number, NCT02928224; EudraCT number, 2015- 005805-35.)

S Kopetz, A Grothey, R Yaeger, E Van Cutsem, J Desai, T Yoshino, H Wasan, F Ciardiello, F Loupakis, YS Hong, N Steeghs, TK Guren, HT Arkenau, P Garcia‑Alfonso, P Pfeiffer, S Orlov, S Lonardi, E Elez, TW Kim, JHM Schellens, C Guo, A Krishnan, J Dekervel, V Morris, A Calvo Ferrandiz, LS Tarpgaard, M Braun, A Gollerkeri, C Keir, K Maharry, M Pickard, J Christy‑Bittel, L Anderson, V Sandor and J Tabernero

Read more in The New England Journal of Medicine

Differences in Tumor Microenvironment Dictate T Helper Lineage Polarization and Response to Immune Checkpoint Therapy

Immune checkpoint therapy (ICT) shows encouraging results in a subset of patients with metastatic castration-resistant prostate cancer (mCRPC) but still elicits a sub-optimal response among those with bone metastases. Analysis of patients’ bone marrow samples revealed increased T_h17 instead of T_h1 subsets after ICT. To further evaluate the different tumor microenvironments, we injected mice with prostate tumor cells either subcutaneously or intraosseously. ICT in the subcutaneous CRPC model significantly increases intra-tumoral T_h1 subsets and improves survival. However, ICT fails to elicit an anti- tumor response in the bone CRPC model despite an increase in the intra-tumoral CD4 T cells, which are polarized to T_h17 rather than T_h1 lineage. Mechanistically, tumors in the bone promote osteoclast- mediated bone resorption that releases TGF-β, which restrains T_h1 lineage development. Blocking TGF-β along with ICT increases T_h1 subsets and promotes clonal expansion of CD8 T cells and subsequent regression of bone CRPC and improves survival.

Shiping Jiao, Sumit K. Subudhi, Ana Aparicio, Zhongqi Ge, Baoxiang Guan, Yuji Miura and Padmanee Sharma

Read more in Cell