Impaired CXCL12 signaling contributes to resistance of pancreatic cancer subpopulations to T cell-mediated cytotoxicity

Pancreatic cancer remains largely unresponsive to immune modulatory therapy attributable in part to an immunosuppressive, desmoplastic tumor microenvironment. Here, we analyze mechanisms of cancer cell-autonomous resistance to T cells. We used a 3D co-culture model of cancer cell spheroids from the KPC (LSL-Kras(G12D/+)/LSL-Trp53(R172H/+)/p48-Cre) pancreatic ductal adenocarcinoma (PDAC) model, to examine interactions with tumor-educated T cells isolated from draining lymph nodes of PDAC-bearing mice. Subpopulations of cancer cells resistant to these tumor-educated T cells were isolated from the in vitro co-culture and their properties compared with sensitive cancer cells. In co-culture with resistant cancer cell subpopulations, tumor-educated T cells showed reduced effector T cell functionality, reduced infiltration into tumor cell spheroids and decreased induction of apoptosis. A combination of comparative transcriptomic analyses, cytometric and immunohistochemistry techniques allowed us to dissect the role of differential gene expression and signaling pathways between sensitive and resistant cells. A decreased expression of the chemokine CXCL12 (SDF-1) was revealed as a common feature in the resistant cell subpopulations. Adding back CXCL12 reversed the resistant phenotype and was inhibited by the CXCR4 inhibitor AMD3100 (plerixafor). We conclude that reduced CXCL12 signaling contributes to PDAC subpopulation resistance to T cell-mediated attack

A Bayesian two-step integrative procedure incorporating prior knowledge for the identification of miRNA-mRNAs involved in hepatocellular carcinoma

Recent studies have confirmed the role of miRNA regulation of gene expression in oncogenesis for various cancers. In parallel, prior knowledge about relationships between miRNA and mRNA have been accumulated from biological experiments or statistical analyses. Improved identification of disease-associated miRNA-mRNA pairs may be achieved by incorporating prior knowledge into integrative genomic analyses. In this study we focus on 39 patients with hepatocellular carcinoma (HCC) and 25 patients with liver cirrhosis and use a flexible Bayesian two-step integrative method. We found 66 significant miRNA-mRNA pairs, several of which contain molecules that have previously been identified as potential biomarkers. These results demonstrate the utility of the proposed approach in providing a better understanding of relationships between different biological levels, thereby giving insights into the biological mechanisms underlying the diseases, while providing a better selection of biomarkers that may serve as diagnostic, prognostic, or therapeutic biomarker candidates

Cardiomyocyte-Specific Circulating Cell-Free Methylated DNA in Esophageal Cancer Patients Treated with Chemoradiation

Thoracic high-dose radiation therapy (RT) for cancer has been associated with early and late cardiac toxicity. To assess altered rates of cardiomyocyte cell death due to RT we monitored changes in cardiomyocyte-specific, cell-free methylated DNA (cfDNA) shed into the circulation. Eleven patients with distal esophageal cancer treated with neoadjuvant chemoradiation to 50.4 Gy (RT) and concurrent carboplatin and paclitaxel were enrolled. Subjects underwent fasting blood draws prior to the initiation and after completion of RT as well as 4–6 months following RT. An island of six unmethylated CpGs in the FAM101A locus was used to identify cardiomyocyte-specific cfDNA in serum. After bisulfite treatment this specific cfDNA was quantified by amplicon sequencing at a depth of >35,000 reads/molecule. Cardiomyocyte-specific cfDNA was detectable before RT in the majority of patient samples and showed some distinct changes during the course of treatment and recovery. We propose that patient-specific cardiac damages in response to the treatment are indicated by these changes although co-morbidities may obscure treatment-specific events

Handbook of Cardiovascular Behavioral Medicine

Handbook of Cardiovascular Behavioral Medicin