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Background: Clinical response to chemotherapy for ovarian cancer is frequently compromised by the development of drug-resistant disease. The underlying molecular mechanisms and implications for prescription of routinely prescribed chemotherapy drugs are poorly understood. Methods: We created novel A2780-derived ovarian cancer cell lines resistant to paclitaxel and olaparib following continuous incremental drug selection. MTT assays were used to assess chemosensitivity to paclitaxel and olaparib in drug-sensitive and drug-resistant cells±the ABCB1 inhibitors verapamil and elacridar and cross-resistance to cisplatin, carboplatin, doxorubicin, rucaparib, veliparib and AZD2461. ABCB1 expression was assessed by qRT-PCR, copy number, western blotting and immunohistochemical analysis and ABCB1 activity assessed by the Vybrant and P-glycoprotein-Glo assays. Results: Paclitaxel-resistant cells were cross-resistant to olaparib, doxorubicin and rucaparib but not to veliparib or AZD2461. Resistance correlated with increased ABCB1 expression and was reversible following treatment with the ABCB1 inhibitors verapamil and elacridar. Active efflux of paclitaxel, olaparib, doxorubicin and rucaparib was confirmed in drug-resistant cells and in ABCB1 -expressing bacterial membranes. Conclusions: We describe a common ABCB1 -mediated mechanism of paclitaxel and olaparib resistance in ovarian cancer cells. Optimal choice of PARP inhibitor may therefore limit the progression of drug-resistant disease, while routine prescription of first-line paclitaxel may significantly limit subsequent chemotherapy options in ovarian cancer patients.

Background: Tumour-infiltrating lymphocytes (TILs) are associated with improved survival in several epithelial cancers. The two chemokines CXCL9 and CXCL10 facilitate chemotactic recruitment of TILs, and their intratumoral accumulation is a conceivable way to improve TIL-dependent immune intervention in cancer. However, the prognostic impact of CXCL9 and CXCL10 in high-grade serous ovarian cancer (HGSC) is largely unknown. Methods: One hundred and eighty four cases of HGSC were immunohistochemically analyzed for CXCL9, CXCL10. TILs were assessed using CD3, CD56 and FOXP3 staining. Chemokine regulation was investigated using the ovarian cancer cell lines OV-MZ-6 and SKOV-3. Results: High expression of CXCL9 and CXCL10 was associated with an approximately doubled overall survival ( n =70, CXCL9: HR 0.41; P =0.006; CXCL10: HR 0.46; P =0.010) which was confirmed in an independent validation set ( n =114; CXCL9: HR 0.60; P =0.019; CXCL10: HR 0.52; P =0.005). Expression of CXCR3 ligands significantly correlated with TILs. In human ovarian cancer cell lines the cyclooxygenase (COX) metabolite Prostaglandin E2 was identified as negative regulator of chemokine secretion, whereas COX inhibition by indomethacin significantly upregulated CXCL9 and CXCL10. In contrast, celecoxib, the only COX inhibitor prospectively evaluated for therapy of ovarian cancer, suppressed NF- κ B activation and inhibited chemokine release. Conclusion: Our results support the notion that CXCL9 and CXCL10 exert tumour-suppressive function by TIL recruitment in human ovarian cancer. COX inhibition by indomethacin, not by celecoxib, may be a promising approach to concomitantly improve immunotherapies.

Background: Chemoresistance is a significant clinical problem in pancreatic cancer (PC) and underlying molecular mechanisms still remain to be completely understood. Here we report a novel exosome-mediated mechanism of drug-induced acquired chemoresistance in PC cells. Methods: Differential ultracentrifugation was performed to isolate extracellular vesicles (EVs) based on their size from vehicle- or gemcitabine-treated PC cells. Extracellular vesicles size and subtypes were determined by dynamic light scattering and marker profiling, respectively. Gene expression was examined by qRT-PCR and/or immunoblot analyses, and direct targeting of DCK by miR-155 was confirmed by dual-luciferase 3′-UTR reporter assay. Flow cytometry was performed to examine the apoptosis indices and reactive oxygen species (ROS) levels in PC cells using specific dyes. Cell viability was determined using the WST-1 assay. Results: Conditioned media (CM) from gemcitabine-treated PC cells (Gem-CM) provided significant chemoprotection to subsequent gemcitabine toxicity and most of the chemoresistance conferred by Gem-CM resulted from its EVs fraction. Sub-fractionation grouped EVs into distinct subtypes based on size distribution and marker profiles, and exosome (Gem-Exo) was the only sub-fraction that imparted chemoresistance. Gene expression analyses demonstrated upregulation of SOD2 and CAT (ROS-detoxifying genes), and downregulation of DCK (gemcitabine-metabolising gene) in Gem-Exo-treated cells. SOD/CAT upregulation resulted, at least in part, from exosome-mediated transfer of their transcripts and they suppressed basal and gemcitabine-induced ROS production, and partly promoted chemoresistance. DCK downregulation occurred through exosome-delivered miR-155 and either the functional suppression of miR-155 or restoration of DCK led to marked abrogation of Gem-Exo-mediated chemoresistance. Conclusions: Together, these findings establish a novel role of exosomes in mediating the acquired chemoresistance of PC.

Background: Ipilimumab improves the survival of metastatic melanoma patients. Despite documented, durable objective responses, a significant number of patients fails to benefit from treatment. The aim of this study was to identify an upfront marker for treatment benefit. Methods: A total of 187 metastatic melanoma patients treated in three Italian Institutions with 3 mg kg −1 ipilimumab, and 27 patients treated with 10 mg kg −1 ipilimumab, were evaluated. Neutrophil-to-lymphocyte ratio (NLR) was calculated from pre-therapy full blood counts. Progression-free survival (PFS) and overall survival (OS) were assessed using the Kaplan–Meier method, and multivariate Cox models were applied, adjusting for confounders and other prognostic factors. Results: In the training cohort of 69 patients treated at European Institute of Oncology, pre-therapy NLR was identified as the strongest and independent marker for treatment benefit in multivariate analyses. Patients with baseline NLR<5 had a significantly improved PFS (HR=0.38; 95% CI: 0.22–0.66; P =0.0006) and OS (HR=0.24; 95% CI: 0.13–0.46; P <0.0001) compared with those with a NLR⩾5. Associations of low NLR with improved survival were confirmed in three validation cohorts of patients. Conclusion: Our findings show that baseline NLR is strongly and independently associated with outcome of patients treated with ipilimumab, and may serve to identify patients most likely to benefit from this therapy.

Background: Metastatic colorectal cancer (mCRC) that harbours a BRAF V600E mutation ( BRAF MT) is associated with poorer outcomes. However, whether this mutation is predictive of treatment benefit from anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (mAbs) is uncertain. Methods: We conducted a systematic review and meta-analysis of randomised controlled trials (RCTs) published up to July 2014 that evaluated the effect of BRAF MT on the treatment benefit from anti-EGFR mAbs for mCRC. Results: Seven RCTs met the inclusion criteria for assessment of overall survival (OS), whereas eight RCTs met the inclusion criteria for assessment of progression-free survival (PFS). For RAS WT/ BRAF MT tumours, the hazard ratio for OS benefit with anti-EGFR mAbs was 0.97 (95% CI; 0.67–1.41), whereas the hazard ratio was 0.81 (95% CI; 0.70–0.95) for RAS WT/ BRAF WT tumours. However, the test of interaction ( P =0.43) was not statistically significant, highlighting that the observed differences in the effect of anti-EGFR mAbs on OS according to the BRAF mutation status may be due to chance alone. Regarding PFS benefit with anti-EGFR mAbs, the hazard ratio was 0.86 (95% CI; 0.61–1.21) for RAS WT/ BRAF MT tumours as compared with 0.62 (95% CI; 0.50–0.77) for RAS WT/ BRAF WT tumours (test of interaction, P =0.07). Interpretation: This meta-analysis demonstrates that there is insufficient evidence to definitively state that RAS WT/ BRAF MT individuals attain a different treatment benefit from anti-EGFR mAbs for mCRC compared with RAS WT/ BRAF WT individuals. As such, there are insufficient data to justify the exclusion of anti-EGFR mAb therapy for patients with RAS WT/ BRAF MT mCRC.

Background: Plasma is an ionised gas that is typically generated in high-temperature laboratory conditions. However, recent progress in atmospheric plasmas has led to the creation of cold plasmas with ion temperature close to room temperature. Methods: Both in-vitro and in-vivo studies revealed that cold plasmas selectively kill cancer cells. Results: We show that: (a) cold plasma application selectively eradicates cancer cells in vitro without damaging normal cells; and (b) significantly reduces tumour size in vivo . It is shown that reactive oxygen species metabolism and oxidative stress responsive genes are deregulated. Conclusion: The development of cold plasma tumour ablation has the potential of shifting the current paradigm of cancer treatment and enabling the transformation of cancer treatment technologies by utilisation of another state of matter.

Background: Agents targeting programmed death-1 receptor (PD-1) and its ligand (PD-L1) are showing promising results in non-small-cell lung cancer (NSCLC). It is unknown whether PD-1/PD-L1 are differently expressed in oncogene-addicted NSCLC. Methods: We analysed a cohort of 125 NSCLC patients, including 56 EGFR mutated, 29 KRAS mutated, 10 ALK translocated and 30 EGFR/KRAS/ALK wild type. PD-L1 and PD-1 expression were assessed by immunohistochemistry. All cases with moderate or strong staining (2+/3+) in >5% of tumour cells were considered as positive. Results: PD-1 positive (+) was significantly associated with current smoking status ( P =0.02) and with the presence of KRAS mutations ( P =0.006), whereas PD-L1+ was significantly associated to adenocarcinoma histology ( P =0.005) and with presence of EGFR mutations ( P =0.001). In patients treated with EGFR tyrosine kinase inhibitors ( N =95), sensitivity to gefitinib or erlotinib was higher in PD-L1+ vs PD-L1 negative in terms of the response rate (RR: P =0.01) time to progression (TTP: P <0.0001) and survival (OS: P =0.09), with no difference in PD1+ vs PD-1 negative. In the subset of 54 EGFR mutated patients, TTP was significantly longer in PD-L1+ than in PD-L1 negative ( P =0.01). Conclusions: PD-1 and PD-L1 are differentially expressed in oncogene-addicted NSCLC supporting further investigation of specific checkpoint inhibitors in combination with targeted therapies.

Background: Genistein is a natural isoflavone with many health benefits, including antitumour effects. Increased hypoxia-inducible factor 1 α (HIF-1 α ) levels and glycolysis in tumour cells are associated with an increased risk of mortality, cancer progression, and resistance to therapy. However, the effect of genistein on HIF-1 α and glycolysis in hepatocellular carcinoma (HCC) is still unclear. Methods: Cell viability, apoptosis rate, lactate production, and glucose uptake were measured in HCC cell lines with genistein incubation. Lentivirus-expressed glucose transporter 1 (GLUT1) or/and hexokinase 2 (HK2) and siRNA of HIF-1 α were used to test the direct target of genistein. Subcutaneous xenograft mouse models were used to measure in vivo efficacy of genistein and its combination with sorafenib. Results: Genistein inhibited aerobic glycolysis and induced mitochondrial apoptosis in HCC cells. Neither inhibitors nor overexpression of HK2 or GLUTs enhance or alleviate this effect. Although stabiliser of HIF-1 α reversed the effect of genistein, genistein no longer has effects on HIF-1 α siRNA knockdown HCC cells. In addition, genistein enhanced the antitumour effect of sorafenib in sorafenib-resistant HCC cells and HCC-bearing mice. Conclusions: Genistein sensitised aerobic glycolytic HCC cells to apoptosis by directly downregulating HIF-1 α , therefore inactivating GLUT1 and HK2 to suppress aerobic glycolysis. The inhibitory effect of genistein on tumour cell growth and glycolysis may help identify effective treatments for HCC patients at advanced stages.

Background: Lurbinectedin is a novel anticancer agent currently undergoing late-stage (Phase II /III) clinical evaluation in platinum-resistant ovarian, BRCA1/2-mutated breast and small-cell lung cancer. Lurbinectedin is structurally related to trabectedin and it inhibits active transcription and the DNA repair machinery in tumour cells. Methods: In this study we investigated whether lurbinectedin has the ability to modulate the inflammatory microenvironment and the viability of myeloid cells in tumour-bearing mice. Results: Administration of lurbinectedin significantly and selectively decreased the number of circulating monocytes and, in tumour tissues, that of macrophages and vessels. Similar findings were observed when a lurbinectedin-resistant tumour variant was used, indicating a direct effect of lurbinectedin on the tumour microenviroment. In vitro , lurbinectedin induced caspase-8-dependent apoptosis of human purified monocytes, whereas at low doses it significantly inhibited the production of inflammatory/growth factors (CCL2, CXCL8 and VEGF) and dramatically impaired monocyte adhesion and migration ability. These findings were supported by the strong inhibition of genes of the Rho-GTPase family in lurbinectedin-treated monocytes. Conclusions: The results illustrate that lurbinectedin affects at multiple levels the inflammatory microenvironment by acting on the viability and functional activity of mononuclear phagocytes. These peculiar effects, combined with its intrinsic activity against cancer cells, make lurbinectedin a compound of particular interest in oncology.

Background: Eribulin mesilate (eribulin), a non-taxane microtubule dynamics inhibitor, has shown trends towards greater overall survival (OS) compared with progression-free survival in late-stage metastatic breast cancer patients in the clinic. This finding suggests that eribulin may have additional, previously unrecognised antitumour mechanisms beyond its established antimitotic activity. To investigate this possibility, eribulin’s effects on the balance between epithelial–mesenchymal transition (EMT) and mesenchymal–epithelial transition (MET) in human breast cancer cells were investigated. Methods: Triple negative breast cancer (TNBC) cells, which are oestrogen receptor (ER−)/progesterone receptor (PR−)/human epithelial growth receptor 2 (HER2−) and have a mesenchymal phenotype, were treated with eribulin for 7 days, followed by measurement of EMT-related gene and protein expression changes in the surviving cells by quantitative real-time PCR (qPCR) and immunoblot, respectively. In addition, proliferation, migration, and invasion assays were also conducted in eribulin-treated cells. To investigate the effects of eribulin on TGF- β /Smad signalling, the phosphorylation status of Smad proteins was analysed. In vivo , the EMT/MET status of TNBC xenografts in mice treated with eribulin was examined by qPCR, immunoblot, and immunohistochemical analysis. Finally, an experimental lung metastasis model was utilised to gauge the metastatic activity of eribulin-treated TNBC in the in vivo setting. Results: Treatment of TNBC cells with eribulin in vitro led to morphological changes consistent with transition from a mesenchymal to an epithelial phenotype. Expression analyses of EMT markers showed that eribulin treatment led to decreased expression of several mesenchymal marker genes, together with increased expression of several epithelial markers. In the TGF- β induced EMT model, eribulin treatment reversed EMT, coincident with inhibition of Smad2 and Smad3 phosphorylation. Consistent with these changes, TNBC cells treated with eribulin for 7 days showed decreased capacity for in vitro migration and invasiveness. In in vivo xenograft models, eribulin treatment reversed EMT and induced MET as assessed by qPCR, immunoblot, and immunohistochemical analyses of epithelial and mesenchymal marker proteins. Finally, surviving TNBC cells pretreated in vitro with eribulin for 7 days led to decreased numbers of lung metastasis when assessed in an in vivo experimental metastasis model. Conclusions: Eribulin exerted significant effects on EMT/MET-related pathway components in human breast cancer cells in vitro and in vivo , consistent with a phenotypic switch from mesenchymal to epithelial states, and corresponding to observed decreases in migration and invasiveness in vitro as well as experimental metastasis in vivo . These preclinical findings may provide a plausible scientific basis for clinical observations of prolonged OS by suppression of further spread of metastasis in breast cancer patients treated with eribulin.