Modulation of Immune Checkpoints by Chemotherapy in Human Colorectal Liver Metastases.

Metastatic colorectal cancer (CRC) is a major cause of cancer-related death, and incidence is rising in younger populations (younger than 50 years). Current chemotherapies can achieve response rates above 50%, but immunotherapies have limited value for patients with microsatellite-stable (MSS) cancers. The present study investigates the impact of chemotherapy on the tumor immune microenvironment. We treat human liver metastases slices with 5-fluorouracil (5-FU) plus either irinotecan or oxaliplatin, then perform single-cell transcriptome analyses. Results from eight cases reveal two cellular subtypes with divergent responses to chemotherapy. Susceptible tumors are characterized by a stemness signature, an activated interferon pathway, and suppression of PD-1 ligands in response to 5-FU+irinotecan. Conversely, immune checkpoint TIM-3 ligands are maintained or upregulated by chemotherapy in CRC with an enterocyte-like signature, and combining chemotherapy with TIM-3 blockade leads to synergistic tumor killing. Our analyses highlight chemomodulation of the immune microenvironment and provide a framework for combined chemo-immunotherapies

Intratumoral T-cell receptor repertoire composition predicts overall survival in patients with pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy that is refractory to immune checkpoint inhibitor therapy. However, intratumoral T-cell infiltration correlates with improved overall survival (OS). Herein, we characterized the diversity and antigen specificity of the PDAC T-cell receptor (TCR) repertoire to identify novel immune-relevant biomarkers. Demographic, clinical, and TCR-beta sequencing data were collated from 353 patients across three cohorts that underwent surgical resection for PDAC. TCR diversity was calculated using Shannon Wiener index, Inverse Simpson index, and True entropy. Patients were clustered by shared repertoire specificity. TCRs predictive of OS were identified and their associated transcriptional states were characterized by single-cell RNAseq. In multivariate Cox regression models controlling for relevant covariates, high intratumoral TCR diversity predicted OS across multiple cohorts. Conversely, in peripheral blood, high abundance of T-cells, but not high diversity, predicted OS. Clustering patients based on TCR specificity revealed a subset of TCRs that predicts OS. Interestingly, these TCR sequences were more likely to encode CD

Tumor slice culture as a biologic surrogate of human cancer.

Background: The tumor microenvironment (TME) is critical to every aspect of cancer biology. Organotypic tumor slice cultures (TSCs) preserve the original TME and have demonstrated utility in predicting drug sensitivity, but the association between clinicopathologic parameters and Methods: One hundred and eight fresh tumor specimens from liver resections at a tertiary academic center were procured and precisely cut with a Vibratome to create 250 μm × 6 mm slices. These fixed-dimension TSCs were grown on polytetrafluoroethylene inserts, and their metabolic activities were determined by a colorimetric assay. Correlation between baseline activities and clinicopathologic parameters was assessed. Tissue CEA mRNA expression was determined by RNAseq. Results: By standardizing the dimensions of a slice, we found that adjacent tumor slices have equivalent metabolic activities, while those derived from different tumors exhibit \u3e30-fold range in baseline MTS absorbances, which correlated significantly with the percentage of tumor necrosis based on histologic assessment. Extending this to individual cancers, we were able to detect intra-tumoral heterogeneity over a span of a few millimeters, which reflects differences in tumor cell density and Ki-67 positivity. For colorectal cancers, tissue CEA expression based on RNAseq of tumor slices was found to correlate with clinical response to chemotherapies. Conclusions: We report a standardized method to assess and compare human cancer growth ex vivo across a wide spectrum of tumor samples. TSC reflects the state of tumor behavior and heterogeneity, thus providing a simple approach to study of human cancers with an intact TME

Protocol for tissue slice cultures from human solid tumors to study therapeutic response

Summary: The impact of systemic therapy on the tumor microenvironment has been difficult to study in human solid tumors. Our protocol describes steps for establishing slice cultures to investigate response to chemotherapies, immunotherapies, or adoptive cell therapies. Endpoints include changes in viability, histology, live-cell imaging, and multi-omics analyses. The protocol has been applied to a broad array of gastrointestinal malignancies. Culture conditions and treatment parameters can be modified for specific experiments. The platform is highly flexible and easy to manipulate.For complete details on the use and execution of this protocol, please refer to Kenerson et al. (2020), Jabbari et al. (2020), Brempelis et al. (2020), and Jiang et al. (2017)

Standardization of perioperative care facilitates safe discharge by postoperative day five after pancreaticoduodenectomy.

IntroductionPancreaticoduodenectomy is a complex surgical procedure associated with high morbidity and prolonged length of stay. Enhanced recovery after surgery principles have reduced complications rate and length of stay for multiple types of operations. We hypothesized that implementation of a standardized perioperative care pathway would facilitate safe discharge by five days after pancreaticoduodenectomy.MethodsWe performed a retrospective cohort study of patients undergoing pancreaticoduodenectomy 18 months prior to and 18 months following implementation of a perioperative care pathway at a quaternary center performing high volume pancreatic surgery.ResultsA total of 145 patients underwent pancreaticoduodenectomy (mean age 63 ± 10 years, 52% female), 81 before and 64 following pathway implementation, and the groups were similar in terms of preoperative comorbidities. The percentage of patients discharged within 5 days of surgery increased from 36% to 64% following pathway implementation (p = 0.001), with no observed differences in post-operative serious adverse events (p = 0.34), pancreatic fistula grade B or C (p = 0.28 and p = 0.27 respectively), or delayed gastric emptying (p = 0.46). Multivariate regression analysis showed length of stay ≤5 days three times more likely after pathway implementation. Rates of readmission within 30 days (20% pre- vs. 22% post-pathway (p = 0.75)) and 90 days (27% pre- vs. 36% post-pathway (p = 0.27)) were unchanged after pathway implementation, and were no different between patients discharged before or after day 5 at both 30 days (19% ≤5 days vs. 23% ≥ 6 days (p = 0.68)) and 90 days (32% ≤5 days vs. 30% ≥ 6 days (p = 0.81)).ConclusionsStandardizing perioperative care via enhanced recovery protocols for patients undergoing pancreaticoduodenectomy facilitates safe discharge by post-operative day five