Clinical impact of chemotherapy to improve tumor microenvironment of pancreatic cancer

Prognostic value of circulating T-lymphocyte subsets in advanced pancreatic cancer patients treated with mFOLFIRINOX or gemcitabine

Advanced pancreatic ductal adenocarcinoma (PDAC) is commonly treated with a chemotherapy combination of mFOLFIRINOX or gemcitabine. However, predictive and prognostic factors for choosing a more appropriate treatment strategy are still lacking. This study aimed to evaluate how chemotherapy changes immune system parameters and whether these changes influence survival outcomes. We sought to identify an easily accessible marker to help choose the appropriate treatment. Patients with PDAC who were suitable for systemic chemotherapy were eligible for the study. Peripheral blood samples were obtained at baseline and after two months of treatment. Lymphocyte subsets were measured using flow cytometry. Correlation with clinical features and survival analyses were performed. In total, 124 patients were enrolled in this study. Seventy patients were treated with mFOLFIRINOX and 50 with gemcitabine monotherapy. Four patients could not be treated because of rapid deterioration. During overall survival analysis (OS), significant factors included age, Eastern Cooperative Oncology Group (ECOG) performance status, differentiation grade G3, carcinoma antigen (CA) 19-9 more than 100 kU/L, absolute white blood cell count, CD3 + CD8+, and CD8 + CD57-T lymphocytes. Natural killer CD3-CD56 + CD16 + and CD3-CD56 + CD16- and T regulatory CD4 + FOXP3 + and CD3 + CD56 + cells differed during treatment, but these differences did not influence the survival results. At baseline, CD8 + CD57- T lymphocyte count demonstrated a clear independent impact on progression-free survival and OS. Gemcitabine showed better survival in patients with extremely low baseline CD8 + CD57- levels. Therefore, circulating CD3 + CD8 + and CD8 + CD57- cells measured before treatment in PDAC may be considered prognostic and predictive biomarkers.

The Role of Immunotherapy in Pancreatic Cancer

Pancreatic adenocarcinoma remains one of the most lethal cancers globally, with a significant need for improved therapeutic options. While the recent breakthroughs of immunotherapy through checkpoint inhibitors have dramatically changed treatment paradigms in other malignancies based on considerable survival benefits, this is not so for pancreatic cancer. Chemotherapies with modest benefits are still the cornerstone of advanced pancreatic cancer treatment. Pancreatic cancers are inherently immune-cold tumors and have been largely refractory to immunotherapies in clinical trials. Understanding and overcoming the current failures of immunotherapy through elucidating resistance mechanisms and developing novel therapeutic approaches are essential to harnessing the potential durable benefits of immune-modulating therapy in pancreatic cancer patients.

Insights into stimuli-responsive diselenide bonds utilized in drug delivery systems for cancer therapy

Due to the complexity and particularity of cancer cell microenvironments, redox responsive drug delivery systems (DDSs) for cancer therapy have been extensively explored. Compared with widely reported cancer treatment systems based on disulfide bonds, diselenide bonds have better redox properties and greater anticancer efficiency. In this review, the significance and application of diselenide bonds in DDSs are summarized, and the stimulation sensitivity of diselenide bonds is comprehensively reported. The potential and prospects for the application of diselenide bonds in next-generation anticancer drug treatment systems are extensively discussed.

Madecassic acid alleviates colitis-associated colorectal cancer by blocking the recruitment of myeloid-derived suppressor cells via the inhibition of IL-17 expression in γδT17 cells

INTRODUCTION

Madecassic acid (MA), a triterpene compound isolated from Centella Asiatica herbs, has previously been shown to attenuate colitis induced by DSS in mice. In the present study, we address whether and how MA ameliorates colitis-associated colorectal cancer (CAC), which accounts for a considerable proportion of colorectal cancer.

METHODS

CAC was induced by AOM/DSS in mice, and MA was administered orally once a day. To identify the source cells of IL-17 and the target cells for MA reducing the expression of IL-17 in the colons of CAC mice, single-cell suspensions were prepared from the colons of CAC mice and analyzed by flow cytometry. An adoptive transfer experiment was performed to verify the importance of the decreasing γδT17 cell population in the anti-CAC effect of MA.

RESULTS

Oral administration of MA reduced the burden and incidence of tumors in the CAC mice. MA decreased the number of MDSCs in the colon tissues of CAC mice and ameliorated anti-tumor immune responses. MA could prevent the migration of MDSCs by inhibiting the activation of γδT17 cells and the expression of chemokines. The population of activated-γδT17 cells in the tumor microenvironment of CAC mice positively correlated with the number of MDSCs and tumors as well as tumor load. Moreover, the anti-CAC effect of MA was significantly counteracted by the adoptive transfer of γδT17 cells.

CONCLUSIONS

MA alleviates CAC by blocking the recruitment of MDSCs to increase the population of anti-tumor immune cells in tumor microenvironment via inhibition of the activation of γδT17 cells.

Polymer nanoparticle-assisted chemotherapy of pancreatic cancer

Pancreatic cancer is a lethal disease characterized by highly dense stroma fibrosis. Only 15-20% of patients with pancreatic cancer have resectable tumors, and only around 20% of them survive to 5 years. Traditional cancer treatments have little effect on their prognosis, and successful surgical resection combined with effective perioperative therapy is the main method for maximizing long-term survival. For this reason, chemotherapy is an adjunct treatment for resectable cancer and is the main therapy for incurable pancreatic cancer, including metastatic pancreatic adenocarcinoma. However, there are various side effects of chemotherapeutic medicine and low drug penetration because the complex tumor microenvironment limits the application of chemotherapy. As a novel strategy, polymer nanoparticles make it possible to target the tumor microenvironment, release cytotoxic agents through various responsive reactions, and thus overcome the treatment barrier. As drug carriers, polymer nanoparticles show marked advantages, such as increased drug delivery and efficiency, controlled drug release, decreased side effects, prolonged half-life, and evasion of immunogenic blockade. In this review, we discuss the factors that cause chemotherapy obstacles in pancreatic cancer, and introduce the application of polymer nanoparticles to treat pancreatic cancer.

Pancreatic Cancer UK Grand Challenge: Developments and challenges for effective CAR T cell therapy for pancreatic ductal adenocarcinoma

Death from pancreatic ductal adenocarcinoma (PDAC) is rising across the world and PDAC is predicted to be the second most common cause of cancer death in the USA by 2030. Development of effective biotherapies for PDAC are hampered by late presentation, a low number of differentially expressed molecular targets and a tumor-promoting microenvironment that forms both a physical, collagen-rich barrier and is also immunosuppressive. In 2017 Pancreatic Cancer UK awarded its first Grand Challenge Programme award to tackle this problem. The team plan to combine the use of novel CAR T cells with strategies to overcome the barriers presented by the tumor microenvironment. In advance of publication of those data this review seeks to highlight the key problems in effective CAR T cell therapy of PDAC and to describe pre-clinical and clinical progress in CAR T bio-therapeutics.

Trial watch: Immunogenic cell death induction by anticancer chemotherapeutics

The expression "immunogenic cell death" (ICD) refers to a functionally unique form of cell death that facilitates (instead of suppressing) a T cell-dependent immune response specific for dead cell-derived antigens. ICD critically relies on the activation of adaptive responses in dying cells, culminating with the exposure or secretion of immunostimulatory molecules commonly referred to as "damage-associated molecular patterns". Only a few agents can elicit bona fide ICD, including some clinically established chemotherapeutics such as doxorubicin, epirubicin, idarubicin, mitoxantrone, bleomycin, bortezomib, cyclophosphamide and oxaliplatin. In this Trial Watch, we discuss recent progress on the development of ICD-inducing chemotherapeutic regimens, focusing on studies that evaluate clinical efficacy in conjunction with immunological biomarkers.

Circulating regulatory T cell subsets predict overall survival of patients with unresectable pancreatic cancer

Most patients with pancreatic ductal adenocarcinoma (PDAC) have unresectable cancers with a dismal prognosis, in which cohort chemotherapy is the primary treatment. T cell immune adaption is critical for tumor immune escape and prognosis of this disease. The present study aimed to determine the correlation between peripheral T cell subset distribution in patients with unresectable PDAC and their response to chemotherapy. Two hundred and twelve patients with unresectable PDAC were included whose blood samples were collected for analysis of T cell subsets, including CD3+, CD4+, CD8+, CD8+CD28+ and CD4+CD25+CD127 T cells by flow cytometry before and after gemcitabine-based chemotherapy. Enzyme-linked immunosorbent assay was used to detect the expression levels of tumor growth factor (TGF)-β1, interleukin (IL)-6 and IL-17A in the patients before and after chemotherapy. Univariate and multivariate analyses found that an initial CD4/CD8 ratio or T regulatory (Treg) cell level before any treatment was associated with the prognosis of unresectable PDAC. After two cycles of chemotherapy, there was no significant change in percentages of T cell subsets, except elevation to a higher level of CD3+ T cells. Decreased Tregs or CD4/CD8 ratio after two cycles of chemotherapy predicts a longer overall survival (OS). Levels of Tregs in stable disease (SD) and partial remission (PR) cases significantly decreased after chemotherapy, but increased in progressive disease (PD) patients. There was no correlation between Tregs and the expression level of either TGF-β1 or IL-6. IL-17A expression was elevated in Treg-decreased patients, whereas IL-17A was reduced in Treg-increased patients after chemotherapy. The circulating signature of T cell subsets can predict OS and chemotherapeutic response in patients with unresectable PDAC, and may be attributable to the plasticity of T cell subsets.

CAR T-cell therapy for pancreatic cancer

Chimeric antigen receptor (CAR) T-cell therapy utilizes genetic engineering to redirect a patient's own T cells to target cancer cells. The remarkable results in hematological malignancies prompted investigating this approach in solid tumors such as pancreatic cancer. The complex tumor microenvironment, stromal hindrance in limiting immune response, and expression of checkpoint blockade on T cells pose hurdles. Herein, we summarize the opportunities, challenges, and state of knowledge in targeting pancreatic cancer with CAR T-cell therapy.