Integrative genomic analysis of peritoneal malignant mesothelioma: understanding a case with extraordinary chemotherapy response.

Peritoneal malignant mesothelioma is a rare disease with a generally poor prognosis and poor response to chemotherapy. To improve survival there is a need for increased molecular understanding of the disease, including chemotherapy sensitivity and resistance. We here present an unusual case concerning a young woman with extensive peritoneal mesothelioma who had a remarkable response to palliative chemotherapy (platinum/pemetrexed). Tumor samples collected at surgery before and after treatment were analyzed on the genomic and transcriptional levels (exome sequencing, RNA-seq, and smallRNA-seq). Integrative analysis of single nucleotide and copy-number variants, mutational signatures, and gene expression was performed to provide a comprehensive picture of the disease. LATS1/2 were identified as the main mutational drivers together with homozygous loss of BAP1 and PBRM1, which also may have contributed to the extraordinary chemotherapy response. The presence of the S3 mutational signature is consistent with homologous recombination DNA repair defects due to BAP1 loss. Up-regulation of the PI3K/AKT/mTOR pathway after treatment, supported by deactivated PTEN through miRNA regulation, is associated with cancer progression and could explain chemotherapy resistance. The molecular profile suggests potential benefit from experimental targeting of PARP, EZH2, the PI3K/AKT/mTOR pathway and possibly also from immune checkpoint inhibition. In addition to providing the molecular background for this unusual case of peritoneal mesothelioma, the results show the potential value of integrative genomic analysis in precision medicine.

On-pump versus off-pump coronary artery bypass grafting: more heat-shock protein 70 is released after on-pump surgery.

OBJECTIVES: The use of cardiopulmonary bypass in coronary artery bypass grafting (CABG) may contribute to the postoperative inflammatory response. The molecular chaperone heat-shock protein (HSP) 70 may be induced by ischemia, and has been detected both in the myocardium and in the circulation after CABG. In vitro, extracellular HSP70 may activate both innate and adaptive immunity. Hypothesizing that use of cardiopulmonary bypass (CPB) leads to more circulating HSP70, we explored the release of it in 10 patients undergoing CABG with the use of CPB, and in 10 patients undergoing off-pump surgery CABG (OPCAB). METHODS: Blood samples were taken preoperatively, twice peroperatively, 2 and 6 h postoperatively and the next day. Serum analyses were performed by means of immunoassays. RESULTS: We detected a significant difference in postoperative circulating HSP70 between on-pump and off-pump patients (median peaks of 2849 and 756 pg/ml, respectively, P < 0.01 2 h postoperatively). Interleukin-6 and -8 increased in all patients, without significant differences between the groups. Serum interleukin-10 increased at the end of the operation in 7 of 10 patients operated with cardiopulmonary bypass (median 51.7 pg/ml), but in none of the off-pump patients. Furthermore, in the first group, interleukin-10 correlated with the HSP70 concentration at the end of the operation, r = 0.75, P < 0.05. Serum markers of myocardial damage were higher in conventional than off-pump patients on day 1 postoperatively: median cardiac Troponin T was 0.358 and 0.126 microg/l, respectively, P < 0.01. Correspondingly, median creatine kinase-MB was 23.6 and 7.8 microg/l in on-pump and off-pump patients, respectively, P < 0.001. Peak HSP70 correlated with both Troponin T and creatine kinase-MB measured on day 1. CONCLUSIONS: Significantly more HSP70 was released into the circulation following conventional than following off-pump CABG. Circulating HSP70 may indicate cellular stress or damage. Furthermore, HSPs are suggested as immunoregulatory agents, and may be important in the host defence postoperatively.

Inflammatory response after open heart surgery: release of heat-shock protein 70 and signaling through toll-like receptor-4.

BACKGROUND: Coronary artery bypass grafting with the use of cardiopulmonary bypass is known to mediate an inflammatory response. The stress-inducible heat-shock protein (HSP) 70 has been detected in myocardial cells after CABG, and toll-like receptors (TLRs) are suggested as putative signaling receptors for the HSPs, mediating synthesis of inflammatory cytokines. The main aims of our study were to explore the release of HSP70 and the regulation of monocyte TLR-2 and TLR-4 expression after CABG. METHODS AND RESULTS: Twenty patients referred for elective CABG were included in this study. Using immunoassays, we detected HSP70 in plasma after CABG, with peak concentration immediately after surgery. Interleukin-6 in plasma reached peak concentration 5 hours after surgery. Monocyte CD14, TLR-2, and TLR-4 expression, as analyzed by flow cytometry, was initially downregulated. On day 1, CD14 expression normalized, whereas TLR-2 and TLR-4 expression was upregulated. TLR-4 was significantly upregulated even on postoperative day 2. Additional experiments revealed that peritoneal macrophages from control (C3H/HeN) mice responded to HSP70 with release of tumor necrosis factor, whereas macrophages from mutated TLR-4 (C3H/HeJ) mice were unresponsive. In vitro, human adherent monocytes responded to recombinant HSP70 with interleukin-6 and tumor necrosis factor release. CD14 and TLR-4 monoclonal antibodies inhibited the cytokine response. CONCLUSIONS: In this study, we observed an immediate release of HSP70 into the circulation and a modulation of monocyte TLR-2 and TLR-4 expression after CABG. TLR-4 and CD14 appear to be involved in an HSP70-mediated activation of innate immunity.