Summary Background For patients with advanced hepatocellular carcinoma, sorafenib is the only approved drug worldwide, and outcomes remain poor. We aimed to assess the safety and efficacy of ...nivolumab, a programmed cell death protein-1 (PD-1) immune checkpoint inhibitor, in patients with advanced hepatocellular carcinoma with or without chronic viral hepatitis. Methods We did a phase 1/2, open-label, non-comparative, dose escalation and expansion trial (CheckMate 040) of nivolumab in adults (≥18 years) with histologically confirmed advanced hepatocellular carcinoma with or without hepatitis C or B (HCV or HBV) infection. Previous sorafenib treatment was allowed. A dose-escalation phase was conducted at seven hospitals or academic centres in four countries or territories (USA, Spain, Hong Kong, and Singapore) and a dose-expansion phase was conducted at an additional 39 sites in 11 countries (Canada, UK, Germany, Italy, Japan, South Korea, Taiwan). At screening, eligible patients had Child-Pugh scores of 7 or less (Child-Pugh A or B7) for the dose-escalation phase and 6 or less (Child-Pugh A) for the dose-expansion phase, and an Eastern Cooperative Oncology Group performance status of 1 or less. Patients with HBV infection had to be receiving effective antiviral therapy (viral load <100 IU/mL); antiviral therapy was not required for patients with HCV infection. We excluded patients previously treated with an agent targeting T-cell costimulation or checkpoint pathways. Patients received intravenous nivolumab 0·1–10 mg/kg every 2 weeks in the dose-escalation phase (3+3 design). Nivolumab 3 mg/kg was given every 2 weeks in the dose-expansion phase to patients in four cohorts: sorafenib untreated or intolerant without viral hepatitis, sorafenib progressor without viral hepatitis, HCV infected, and HBV infected. Primary endpoints were safety and tolerability for the escalation phase and objective response rate (Response Evaluation Criteria In Solid Tumors version 1.1) for the expansion phase. This study is registered with ClinicalTrials.gov , number NCT01658878. Findings Between Nov 26, 2012, and Aug 8, 2016, 262 eligible patients were treated (48 patients in the dose-escalation phase and 214 in the dose-expansion phase). 202 (77%) of 262 patients have completed treatment and follow-up is ongoing. During dose escalation, nivolumab showed a manageable safety profile, including acceptable tolerability. In this phase, 46 (96%) of 48 patients discontinued treatment, 42 (88%) due to disease progression. Incidence of treatment-related adverse events did not seem to be associated with dose and no maximum tolerated dose was reached. 12 (25%) of 48 patients had grade 3/4 treatment-related adverse events. Three (6%) patients had treatment-related serious adverse events (pemphigoid, adrenal insufficiency, liver disorder). 30 (63%) of 48 patients in the dose-escalation phase died (not determined to be related to nivolumab therapy). Nivolumab 3 mg/kg was chosen for dose expansion. The objective response rate was 20% (95% CI 15–26) in patients treated with nivolumab 3 mg/kg in the dose-expansion phase and 15% (95% CI 6–28) in the dose-escalation phase. Interpretation Nivolumab had a manageable safety profile and no new signals were observed in patients with advanced hepatocellular carcinoma. Durable objective responses show the potential of nivolumab for treatment of advanced hepatocellular carcinoma. Funding Bristol-Myers Squibb.
Highlights ► We provide an updated view on effector T cell compartment in the tumor microenvironment. ► We describe dysfunctional T cell subsets in the tumor microenvironment. ► We discuss ...co-inhibitory and co-stimulatory molecular networks in the tumor microenvironment. ► We review stem like-memory T cell subsets (e.g. Th17) in the tumor microenvironment. ► We suggest anti-cancer modality by targeting T cell dysfunction and stemness.
Background & Aims Cancer stem cells (CSCs) can contribute to hepatocellular carcinoma (HCC) progression and recurrence after therapy. The presence of tumor-associated macrophages (TAMs) in patients ...with HCC is associated with poor outcomes. It is not clear whether TAMs interact with CSCs during HCC development. We investigated whether TAMs affect the activities of CSCs in the microenvironment of human HCCs. Methods HCCs were collected from 17 patients during surgical resection and single-cell suspensions were analyzed by flow cytometry. CD14+ TAMs were isolated from the HCC cell suspensions and placed into co-culture with HepG2 or Hep3B cells, and CSC functions were measured. The interleukin 6 (IL6) receptor was blocked with a monoclonal antibody (tocilizumab), and signal transducer and activator of transcription 3 was knocked down with small hairpin RNAs in HepG2 cells. Xenograft tumors were grown in NOD-SCID/ Il2 Rgnull mice from human primary HCC cells or HepG2 cells. Results CD44+ cells from human HCCs and cell lines formed more spheres in culture and more xenograft tumors in mice than CD44- cells, indicating that CD44+ cells are CSCs. Incubation of the CD44+ cells with TAMs promoted expansion of CD44+ cells, and increased their sphere formation in culture and formation of xenograft tumors in mice. In human HCC samples, the numbers of TAMs correlated with the numbers of CD44+ cells. Of all cytokines expressed by TAMs, IL6 was increased at the highest level in human HCC co-cultures, compared with TAMs not undergoing co-culture. IL6 was detected in the microenvironment of HCC samples and induced expansion of CD44+ cells in culture. Levels of IL6 correlated with stages of human HCCs and detection of CSC markers. Incubation of HCC cell lines with tocilizumab or knockdown of signal transducer and activator of transcription 3 in HCC cells reduced the ability of TAMs to promote sphere formation by CD44+ cells in culture and growth of xenograft tumors in mice. Conclusions CD44+ cells isolated from human HCC tissues and cell lines have CSC activities in vitro and form a larger number of xenograft tumors in mice than CD44- cells. TAMs produce IL6, which promotes expansion of these CSCs and tumorigenesis. Levels of IL6 in human HCC samples correlate with tumor stage and markers of CSCs. Blockade of IL6 signaling with tocilizumab, a drug approved by the Food and Drug Administration for treatment of rheumatoid arthritis, inhibits TAM-stimulated activity of CD44+ cells. This drug might be used to treat patients with HCC.
Hepatocellular carcinoma (HCC) is highly associated with inflammation. Myeloid cells, including tumor‐associated macrophages and myeloid‐derived suppressor cells, are abundant in the HCC ...microenvironment and are often associated with poor prognosis. Myeloid cells in HCC play a vital role in supporting tumor initiation, progression, angiogenesis, metastasis, and therapeutic resistance. Here, we summarize our current knowledge about myeloid cells in HCC and focus on their immune‐suppressive activities and tumor‐promoting functions, as well as the relevance to potential new therapies in HCC. (Hepatology 2015;62:1304‐1312)
Background & Aims Growth of many different tumor types requires a population of self-renewing cancer stem cells (CSCs). c-Met is a marker of normal mouse pancreatic stem and progenitor cells; we ...investigated whether it is also a marker of human pancreatic CSCs that might be developed as a therapeutic target. Methods We studied growth of primary human pancreatic adenocarcinoma in NOD SCID mice. The self-renewal capability of pancreatic cancer cells that expressed high levels of c-Met (c-Methigh ) was assessed using in vitro sphere assays and compared with those that were c-Met negative or expressed low levels of c-Met. The tumorigenicity of c-Methigh pancreatic cancer cells was evaluated in NOD SCID mice. Results c-Methigh cells readily formed spheres, whereas c-Met–negative cells did not. Use of the c-Met inhibitor XL184 or c-Met knockdown with small hairpin RNAs significantly inhibited tumor sphere formation. c-Methigh cells had increased tumorigenic potential in mice; those that expressed c-Met and CD44 (0.5%–5% of the pancreatic cancer cells) had the capability for self-renewal and the highest tumorigenic potential of all cell populations studied. In pancreatic tumors established in NOD SCID mice, c-Met inhibitors slowed tumor growth and reduced the population of CSCs when given alone or in combination with gemcitabine. Administration of XL184 for 2 weeks after cardiac injection of cancer cells prevented the development of metastases. Conclusions c-Met is a new marker for pancreatic CSCs. It is required for growth and metastasis of pancreatic tumors in mice and is a therapeutic target for pancreatic cancer.
Th17 cells play an active role in autoimmune diseases. However, the nature of Th17 cells is poorly understood in cancer patients. We studied Th17 cells, the associated mechanisms, and clinical ...significance in 201 ovarian cancer patients. Tumor-infiltrating Th17 cells exhibit a polyfunctional effector T-cell phenotype, are positively associated with effector cells, and are negatively associated with tumor-infiltrating regulatory T cells. Tumor-associated macrophages promote Th17 cells through interleukin-1β (IL-1β), whereas tumor-infiltrating regulatory T cells inhibit Th17 cells through an adenosinergic pathway. Furthermore, through synergistic action between IL-17 and interferon-γ, Th17 cells stimulate CXCL9 and CXCL10 production to recruit effector T cells to the tumor microenvironment. The levels of CXCL9 and CXCL10 are associated with tumor-infiltrating effector T cells. The levels of tumor-infiltrating Th17 cells and the levels of ascites IL-17 are reduced in more advanced diseases and positively predict patient outcome. Altogether, Th17 cells may contribute to protective human tumor immunity through inducing Th1-type chemokines and recruiting effector cells to the tumor microenvironment. Inhibition of Th17 cells represents a novel immune evasion mechanism. This study thus provides scientific and clinical rationale for developing novel immune-boosting strategies based on promoting the Th17 cell population in cancer patients.
The tumor microenvironment (TME) in pancreatic ductal adenocarcinoma (PDAC) is a complex ecosystem that drives tumor progression; however, in-depth single cell characterization of the PDAC TME and ...its role in response to therapy is lacking. Here, we perform single-cell RNA sequencing on freshly collected human PDAC samples either before or after chemotherapy. Overall, we find a heterogeneous mixture of basal and classical cancer cell subtypes, along with distinct cancer-associated fibroblast and macrophage subpopulations. Strikingly, classical and basal-like cancer cells exhibit similar transcriptional responses to chemotherapy and do not demonstrate a shift towards a basal-like transcriptional program among treated samples. We observe decreased ligand-receptor interactions in treated samples, particularly between TIGIT on CD8 + T cells and its receptor on cancer cells, and identify TIGIT as the major inhibitory checkpoint molecule of CD8 + T cells. Our results suggest that chemotherapy profoundly impacts the PDAC TME and may promote resistance to immunotherapy.
Aerobic glycolysis regulates T cell function. However, whether and how primary cancer alters T cell glycolytic metabolism and affects tumor immunity in cancer patients remains a question. Here we ...found that ovarian cancers imposed glucose restriction on T cells and dampened their function via maintaining high expression of microRNAs miR-101 and miR-26a, which constrained expression of the methyltransferase EZH2. EZH2 activated the Notch pathway by suppressing Notch repressors Numb and Fbxw7 via trimethylation of histone H3 at Lys27 and, consequently, stimulated T cell polyfunctional cytokine expression and promoted their survival via Bcl-2 signaling. Moreover, small hairpin RNA-mediated knockdown of human EZH2 in T cells elicited poor antitumor immunity. EZH2(+)CD8(+) T cells were associated with improved survival in patients. Together, these data unveil a metabolic target and mechanism of cancer immune evasion.
Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy that harbors mutations in homologous recombination-repair (HR-repair) proteins in 20%-25% of cases. Defects in HR impart a ...specific vulnerability to poly ADP ribose polymerase inhibitors and platinum-containing chemotherapy in tumor cells. However, not all patients who receive these therapies respond, and many who initially respond ultimately develop resistance. Inactivation of the HR pathway is associated with the overexpression of polymerase theta (Polθ, or POLQ). This key enzyme regulates the microhomology-mediated end-joining (MMEJ) pathway of double-strand break (DSB) repair. Using human and murine HR-deficient PDAC models, we found that POLQ knockdown is synthetically lethal in combination with mutations in HR genes such as BRCA1 and BRCA2 and the DNA damage repair gene ATM. Further, POLQ knockdown enhances cytosolic micronuclei formation and activates signaling of cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING), leading to enhanced infiltration of activated CD8+ T cells in BRCA2-deficient PDAC tumors in vivo. Overall, POLQ, a key mediator in the MMEJ pathway, is critical for DSB repair in BRCA2-deficient PDAC. Its inhibition represents a synthetic lethal approach to blocking tumor growth while concurrently activating the cGAS-STING signaling pathway to enhance tumor immune infiltration, highlighting what we believe to be a new role for POLQ in the tumor immune environment.
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