Combination therapy with α-CTLA-4 and α-PD-1 has shown significant clinical responses in different types of cancer. However, the underlying mechanisms remain elusive. Here, combining detailed ...analysis of human tumour samples with preclinical tumour models, we report that concomitant blockade of CTLA-4 and PD-1 improves anti-tumour immune responses and synergistically eradicates tumour. Mechanistically, combination therapy relies on the interdependence between IL-7 and IFN-γ signalling in T cells, as lack of either pathway abrogates the immune-boosting and therapeutic effects of combination therapy. Combination treatment increases IL-7Rα expression on tumour-infiltrating T cells in an IFN-γ/IFN-γR signalling-dependent manner, which may serve as a potential biomarker for clinical trials with immune checkpoint blockade. Our data suggest that combining immune checkpoint blockade with IL-7 signalling could be an effective modality to improve immunotherapeutic efficacy. Taken together, we conclude that combination therapy potently reverses immunosuppression and eradicates tumours via an intricate interplay between IFN-γ/IFN-γR and IL-7/IL-7R pathways.
Abstract Resistance to immune checkpoint therapy (ICT) presents a growing clinical challenge. The tumor microenvironment (TME) and its components, namely tumor-associated macrophages (TAMs) and ...cancer-associated fibroblasts (CAFs), play a pivotal role in ICT resistance; however, the underlying mechanisms remain under investigation. In this study, we identify expression of TNF-Stimulated Factor 6 (TSG-6) in ICT-resistant pancreatic tumors, compared to ICT-sensitive melanoma tumors, both in mouse and human. TSG-6 is expressed by CAFs within the TME, where suppressive macrophages expressing Arg1 , Mafb , and Mrc1 , along with TSG-6 ligand Cd44 , predominate. Furthermore, TSG-6 expressing CAFs co-localize with the CD44 expressing macrophages in the TME. TSG-6 inhibition in combination with ICT improves therapy response and survival in pancreatic tumor-bearing mice by reducing macrophages expressing immunosuppressive phenotypes and increasing CD8 T cells. Overall, our findings propose TSG-6 as a therapeutic target to enhance ICT response in non-responsive tumors.
Altered microRNA (miRNA) expression has been found to promote carcinogenesis, but little is known about the role of miRNAs in esophageal cancer. In this study, we selected 10 miRNAs and analyzed ...their expression in 10 esophageal cancer cell lines and 158 tissue specimens using Northern blotting and in situ hybridization, respectively. We found that Let‐7g, miR‐21 and miR‐195p were expressed in all 10 cell lines, miR‐9 and miR‐20a were not expressed in any of the cell lines, and miR‐16‐2, miR‐30e, miR‐34a, miR‐126 and miR‐200a were expressed in some of the cell lines but not others. In addition, transient transfection of miR‐34a inhibited c‐Met and cyclin D1 expression and esophageal cancer cell proliferation, whereas miR‐16‐2 suppressed RAR‐β2 expression and increased tumor cell proliferation. Furthermore, we found that miR‐126 expression was associated with tumor cell dedifferentiation and lymph node metastasis, miR‐16‐2 was associated with lymph node metastasis, and miR‐195p was associated with higher pathologic disease stages in patients with esophageal adenocarcinoma. Kaplan‐Meier analysis showed that miR‐16‐2 expression and miR‐30e expression were associated with shorter overall and disease‐free survival in all esophageal cancer patients. In addition, miR‐16‐2, miR‐30e and miR‐200a expression were associated with shorter overall and disease‐free survival in patients with esophageal adenocarcinoma; however, miR‐16‐2, miR‐30e and miR‐200a expression were not associated with overall or disease‐free survival in squamous cell carcinoma patients. Our data indicate that further evaluation of miR‐30e and miR‐16‐2 as prognostic biomarkers is warranted in patients with esophageal adenocarcinoma. In addition, the role of miR‐34a in esophageal cancer also warrants further study.
Esophageal adenocarcinoma is increasing in the US and Western countries and frequent gastresophageal reflux or gastresophageal reflux disease carrying gastric acid and bile acid could contribute to ...esophageal adenocarcinogenesis. This study was designed to detect the expression of gastric acid-inducing gene Na＋/H＋ exchanger-1 （NHE-1） ex vivo and then to explore targeting of NHE-1 expression or activity to control esophageal cancer cell viability in vitro and in nude mouse xenografts. The data showed that NHE-1 was highly expressed in esophageal adenocarcinoma tissues （66 of 101 cases 65.3%｜, but not in normal esophageal squamous cell epithelium （1 of 26 cases 3.8~0）. Knockdown of NHE-1 expression using NHE-1 shRNA or inhibition of NHE-1 activity using the NHE-1 inhibitor amiloride suppressed viability and induced apoptosis in esophageal cancer cells. Molecularly, amiloride inhibited expression of cyclooxygenase-2 and matrix metallopeptidase-9 but not NHE-1 mRNA in esophageal cancer cells. A combination of amiloride and guggulsterone （a natural bile acid receptor inhibitor） showed more than additive effects in suppressing esophageal cancer cell growth in vitro and in nude mouse xenografts. This study suggests that inhibition of NHE-1 expression or activity or combination of amiloride and guggulsterone could be useful in control of esophageal adenocarcinoma.
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 Th17 instead of Th1 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 Th1 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 Th17 rather than Th1 lineage. Mechanistically, tumors in the bone promote osteoclast-mediated bone resorption that releases TGF-β, which restrains Th1 lineage development. Blocking TGF-β along with ICT increases Th1 subsets and promotes clonal expansion of CD8 T cells and subsequent regression of bone CRPC and improves survival.
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•Lack of Th1 cells in the tumor confers resistance to immune checkpoint therapy•High TGF-β amounts in prostate cancer bone metastases restrains the Th1 lineage and hinders ICT•Tumors in the bone promote osteoclast-mediated bone resorption that releases TGF-β•TGF-β inhibition allows Th1 development and augments ICT in bone prostate cancer
The response to immune checkpoint therapy in a subset of patients with castration-resistant prostate cancer who develop bone metastases can be improved by promoting CD4 Th1 effector T cell responses and clonal expansion of CD8 T cells through TGF-β blockade
Terminal differentiation is an important event for maintaining normal homeostasis in the colorectal epithelium, and the loss of apoptosis is an important mechanism underlying colorectal ...tumorigenesis. The very limited current data on the role of lipoxygenase (LOX) metabolism in tumorigenesis suggests that the oxidative metabolism of linoleic and arachidonic acid possibly shifts from producing antitumorigenic 15-LOX-1 and 15-LOX-2 products to producing protumorigenic 5-LOX and 12-LOX products. We examined whether this shift occurs in vitro in the human colon cancer cell line Caco-2 in association with the loss of terminal differentiation and apoptosis, or in vivo during the formation of colorectal adenomas in patients with familial adenomatous polyposis (FAP). Restoring terminal differentiation and apoptosis of Caco-2 cells increased the mRNA levels of 5-LOX, 15-LOX-2, and 15-LOX-1, but the only significant increases in protein expression and enzymatic activity were of 15-LOX-1. In FAP patients, 15-LOX-1 expression and activity were significantly down-regulated in adenomas (compared with paired nonneoplastic epithelial mucosa), whereas 5-LOX and 15-LOX-2 protein expressions and enzymatic activities were not. We conducted a validation study with immunohistochemical testing in a second group of FAP patients; 15-LOX-1 expression was down-regulated in colorectal adenomas (compared with nonneoplastic epithelial mucosa) in 87% (13 of 15) of this group. We confirmed the mechanistic relevance of these findings by demonstrating that ectopically restoring 15-LOX-1 expression reestablished apoptosis in Caco-2 cells. Therefore, 15-LOX-1 down-regulation rather than a shift in the balance of LOXs is likely the dominant alteration in LOX metabolism which contributes to colorectal tumorigenesis by repressing apoptosis.
Death receptor 4 (DR4; also called TRAIL-R1), a member of the tumor necrosis factor receptor superfamily, is a cell surface receptor that triggers the apoptotic machinery upon binding to its ligand ...tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Although several chemotherapeutic agents were reported to induce DR4 expression, the mechanism of this effect remains largely unknown. To begin to understand its regulation, we cloned a 1.8 Kb 5'-flanking region of the human DR4 gene and identified several putative binding sites for transcription factors including activator protein 1 (AP-1). Among the three putative AP-1 binding sites, the site located at -350/-344 is functionally active as evidenced by a combination of electrophoretic mobility shift and luciferase reporter assays. The AP-1 activator phorbol 12-myristate 13-acetate (TPA) enhanced the binding of this DR4 AP-1 binding site to protein(s) in a nuclear extract from TPA-treated cells, increased luciferase activity of a reporter construct containing this site and induced DR4 expression at the transcription level. These results indicate that AP-1 regulates DR4 expression via the AP-1 binding site located at -350/-344. AP-1 has been implicated in many critical cellular processes including apoptosis, and is a major target of the c-Jun NH(3)-terminal kinase signaling pathway that is activated by many anticancer drugs. Therefore, our findings may increase the understanding of the mechanisms underlying AP-1-mediated apoptosis as well as drug-induced apoptosis.
Retinoid receptor-induced gene-1 (RRIG1) is a novel gene that has been lost in several types of human cancers. The aim of this study was to determine whether RRIG1 plays a role in breast cancer, such ...as in the suppression of breast cancer cell growth and invasion.
Immunohistochemistry was used to detect RRIG1 expression in breast tissue specimens. Gene transfection was used to restore or knock down RRIG1 expression in breast cancer cell lines for analysis of cell viability, colony formation, and migration/invasion potential. Reverse-transcription polymerase chain reaction and western blot assays were used to detect the changes in gene expression. The RhoA activation assay was used to assess RRIG1-induced inhibition of RhoA activity.
The immunohistochemical data showed that RRIG1 expression was reduced in breast cancer tissues compared with normal and atypical hyperplastic breast tissues. RRIG1 expression was inversely correlated with lymph node metastasis of breast cancer but was not associated with the status of hormone receptors, such as estrogen receptor, progesterone receptor, or HER2. Furthermore, restoration of RRIG1 expression inhibited proliferation, colony formation, migration, and invasion of breast cancer cells. Expression of RRIG1 also reduced phosphorylated Erk1/2 and Akt levels; c-Jun, MMP9, and Akt expressions; and RhoA activity. In contrast, knockdown of RRIG1 expression promoted breast cancer cell proliferation, colony formation, migration, and invasion potential.
The data from the current study indicated that RRIG1 expression was reduced or lost in breast cancer and that restoration of RRIG1 expression suppressed breast cancer cell growth and invasion capacity. Future studies will determine the underlying molecular mechanisms and define RRIG1 as a tumor-suppressor gene in breast cancer.
Immune checkpoint therapy (ICT) can produce durable antitumor responses in metastatic urothelial carcinoma (mUCC); however, the responses are not universal. Despite multiple approvals of ICT in mUCC, ...we lack predictive biomarkers to guide patient selection. The identification of biomarkers may require interrogation of both the tumor mutational status and the immune microenvironment. Through multi-platform immuno-genomic analyses of baseline tumor tissues, we identified the mutation of AT-rich interactive domain-containing protein 1A (
) in tumor cells and expression of immune cytokine CXCL13 in the baseline tumor tissues as two predictors of clinical responses in a discovery cohort (
= 31). Further, reverse translational studies revealed that CXCL13
tumor-bearing mice were resistant to ICT, whereas
knockdown enhanced sensitivity to ICT in a murine model of bladder cancer. Next, we tested the clinical relevance of
mutation and baseline CXCL13 expression in two independent confirmatory cohorts (CheckMate275 and IMvigor210). We found that
mutation and expression of CXCL13 in the baseline tumor tissues correlated with improved overall survival (OS) in both confirmatory cohorts (CheckMate275, CXCL13 data,
= 217; ARID1A data,
= 139, and IMvigor210, CXCL13 data,
= 348; ARID1A data,
= 275). We then interrogated CXCL13 expression plus
mutation as a combination biomarker in predicting response to ICT in CheckMate275 and IMvigor210. Combination of the two biomarkers in baseline tumor tissues suggested improved OS compared to either single biomarker. Cumulatively, this study revealed that the combination of CXCL13 plus ARID1A may improve prediction capability for patients receiving ICT.
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