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Abstract Background CD95 is a death receptor controlling not only apoptotic pathways but also activating mechanisms promoting tumor growth. During the acquisition of chemoresistance to oxaliplatin there is a progressive loss of CD95 expression in colon cancer cells and a decreased ability of this receptor to induce cell death. The aim of this study was to characterize some key cellular responses controlled by CD95 signaling in oxaliplatin-resistant colon cancer cells. Results We show that CD95 triggering results in an increased metastatic ability in resistant cells. Moreover, oxaliplatin treatment itself stimulates cell migration and decreases cell adhesion through CD95 activation, since CD95 expression inhibition by siRNA blocks the promigratory effects of oxaliplatin. These promigratory effects are related to the epithelia-to-mesenchymal transition (EMT) phenomenon, as evidenced by the up-regulation of some transcription factors and mesenchymal markers both in vitro and in vivo. Conclusions We conclude that oxaliplatin treatment in cells that have acquired resistance to oxaliplatin-induced apoptosis results in tumor-promoting effects through the activation of CD95 signaling and by inducing EMT, all these events jointly contributing to a metastatic phenotype.

Androgen receptor (AR) signaling remains crucial in castration-resistant prostate cancer (CRPC). Since it is also essential in immune cells, we studied whether the expression of AR full-length (ARFL) and its splicing variant ARV7 in peripheral blood mononuclear cells (PBMC) predicts systemic treatment response in mCRPC in comparison with circulating-tumor cells (CTC). We measured ARFL and ARV7 mRNA in PBMC and CTC from patients prior to receiving abiraterone (AA), enzalutamide (E), or taxanes by a pre-amplification plus quantitative reverse-transcription PCR. They were also tested in LNCaP- ARV7 -transfected and in 22RV1 docetaxel-resistant (22RV1DR) cells. We studied 171 PBMC from 136 patients and from 24 non-cancer controls, and 47 CTC from 22 patients. High PBMC ARV7 levels correlated with worse AA/E and better taxane response. In taxane-treated patients high PBMC ARFL also correlated with longer progression-free survival (PFS). High ARV7 and ARFL expression were independently associated with better biochemical-PFS. Conversely, high CTC ARV7 and ARFL correlated with shorter radiological-PFS and overall survival, respectively. High ARV7 in 22RV1DR and LNCaP- ARV7 cells correlated with taxane resistance. In conclusion, ARFL and ARV7 at PBMC or CTC have a different predictive role in the taxane response, suggesting a potential influence of the AR pathway from PBMC in such response modulation., Competing Interests: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

Biological changes that occur during metastatic progression of breast cancer are still incompletely characterized. In this study, we compared intrinsic molecular subtypes and gene expression in 123 paired primary and metastatic tissues from breast cancer patients. Intrinsic subtype was identified using a PAM50 classifier and χ 2 tests determined the differences in variable distribution. The rate of subtype conversion was 0% in basal-like tumors, 23.1% in HER2-enriched (HER2-E) tumors, 30.0% in luminal B tumors, and 55.3% in luminal A tumors. In 40.2% of cases, luminal A tumors converted to luminal B tumors, whereas in 14.3% of cases luminal A and B tumors converted to HER2-E tumors. We identified 47 genes that were expressed differentially in metastatic versus primary disease. Metastatic tumors were enriched for proliferation-related and migration-related genes and diminished for luminal-related genes. Expression of proliferation-related genes were better at predicting overall survival in metastatic disease (OSmet) when analyzed in metastatic tissue rather than primary tissue. In contrast, a basal-like gene expression signature was better at predicting OSmet in primary disease compared with metastatic tissue. We observed correlations between time to tumor relapse and the magnitude of changes of proliferation, luminal B, or HER2-E signatures in metastatic versus primary disease. Although the intrinsic subtype was largely maintained during metastatic progression, luminal/HER2-negative tumors acquired a luminal B or HER2-E profile during metastatic progression, likely reflecting tumor evolution or acquisition of estrogen independence. Overall, our analysis revealed the value of stratifying gene expression by both cancer subtype and tissue type, providing clinicians more refined tools to evaluate prognosis and treatment. Cancer Res; 77(9); 2213-21. ©2017 AACR ., (©2017 American Association for Cancer Research.)

TMPRSS2-ERG rearrangement is a genetic alteration exclusive to prostate cancer, associated with taxane resistance in preclinical models. Its detection in blood samples of metastatic resistant prostate cancer (mCRPC) patients may indicate the presence of circulating tumour cells with this genetic alteration and may predict taxane resistance. To test this hypothesis, we evaluated TMPRSS2-ERG expression using quantitative reverse transcription polymerase chain reaction in peripheral blood mononuclear cells and tumour tissue from mCPRC patients treated with taxanes. We examined peripheral blood mononuclear cells from 24 healthy controls, 50 patients treated with docetaxel, and 22 with cabazitaxel. TMPRSS2-ERG was detected in 0%, 16%, and 22.7% of them, respectively. In docetaxel-treated patients TMPRSS2-ERG detection correlated with lower prostatic-specific antigen (PSA) response rate (12.5% vs 68.3%, p=0.005), PSA-progression-free survival (PFS; 3.1 mo vs 7.5 mo, p<0.001), clinical/radiological-PFS (3.1 mo vs 8.2 mo, p<0.001), and it was independently associated with PSA-PFS (hazard ratio 3.7; p=0.009) and clinical/radiological-PFS (hazard ratio 6.3; p<0.001). Moreover, TMPRSS2-ERG also predicted low PSA-PFS to cabazitaxel. At progression, a switch from negative to positive TMPRSS2-ERG was observed in 41% of patients with undetected TMPRSS2-ERG at the baseline sample. Tissue TMPRSS2-ERG expression correlated with lower PSA-PFS (p=0.02) to docetaxel. Our findings support the potential role of TMPRSS2-ERG detection as a biomarker to tailor treatment strategies., Patient Summary: Taxanes are the most active chemotherapy agents in metastatic resistant prostate cancer. However, not all patients respond to this therapy. In the present study we show that the detection of TMPRSS2-ERG in blood from metastatic resistant prostate cancer patients predicts resistance to docetaxel and it may be useful to select treatment and to avoid possible toxicities in refractory patients., (Copyright © 2016 European Association of Urology. Published by Elsevier B.V. All rights reserved.)

The enumeration of circulating tumor cells (CTCs) in peripheral blood correlates with clinical outcome in castration-resistant prostate cancer (CRPC). We analyzed the molecular profiling of peripheral blood from 43 metastatic CRPC patients with known CTC content in order to identify genes that may be related to prostate cancer progression. Global gene expression analysis identified the differential expression of 282 genes between samples with ≥5 CTCs vs <5 CTCs, 58.6% of which were previously described as over-expressed in prostate cancer (18.9% in primary tumors and 56.1% in metastasis). Those genes were involved in survival functions such as metabolism, signal transduction, gene expression, cell growth, death, and movement. The expression of selected genes was evaluated by quantitative RT-PCR. This analysis revealed a two-gene model (SELENBP1 and MMP9) with a high significant prognostic ability (HR 6; 95% CI 2.61 - 13.79; P<0.0001). The combination of the two-gene signature plus the CTCs count showed a higher prognostic ability than CTCs enumeration or gene expression alone (P<0.05). This study shows a gene expression profile in PBMNC associated with CTCs count and clinical outcome in metastatic CRPC, describing genes and pathways potentially associated with CRPC progression.

NK1 is a tachykinin receptor highly relevant to tumorigenesis and metastasis development in breast cancer and other carcinomas. Despite the substantial efforts done to develop potent NK1 receptor antagonists, none of these antagonists had shown good antitumor activity in clinical trials. Now, we have tested the effect of inhibition of the neuropeptide Substance P (SP), a NK1 ligand, as a potential therapeutic approach in cancer. We found that the inhibition of SP with antibodies strongly inhibit cell growth and induce apoptosis in breast, colon, and prostate cancer cell lines. These effects were accompained by a decrease in the mitogen-activated kinase singaling pathway. Interestingly, in some cell lines SP abrogation decreased the steady state of Her2 and EGFR, suggesting that SP-mediated signaling is important for the basal activity of these ErbB receptors. In consequence, we observed a blockade of the cell cycle progression and the inhibition of several cell cycle-related proteins including mTOR. SP inhibition also induced cell death in cell lines resistant to Lapatinib and Trastuzumab that have increased levels of active Her2, suggesting that this therapeutic approach could be also effective for those cancers resistant to current anti-ErbB therapies. Thus, we propose a new therapeutic strategy for those cancers that express NK1 receptor and/or other tachykinin receptors, based in the immuno-blockade of the neuropeptide SP., (Copyright © 2011 Wiley Periodicals, Inc.)

Background: We have previously shown that metalloproteinase 7 (MMP7) expression is increased during the acquisition of resistance to oxaliplatin in colon cancer cells. Now we have analyzed the implication of β-catenin and EGFR pathways in the up-regulation of MMP7 in the oxaliplatin-resistant human colon cancer cell lines RHT29 and RHCT116 p53-/-, derived from the HT29 and HCT116 p53-/- cells, respectively., Results: Oxaliplatin treatment increased EGFR expression and induced its activation in all the cell lines. However, β-catenin mRNA was only upregulated in the HT29 and RHT29 cells, with a marked increase in the nuclear/cytoplasmic β-catenin protein ratio in the oxaliplatin-resistant RHT29 cells. To determine the contribution of β-catenin and EGFR to the expression of MMP7 we performed siRNA experiments. β-catenin abrogation only prevented the induction of MMP7 by oxaliplatin in HT29 and RHT29 cells. Accordingly, viability of oxaliplatin-treated RHT29 cells under β-catenin silencing was decreased. On the other hand, EGFR siRNA induced contradictory effects, decreasing PEA3 and MMP7 expression in control and oxaliplatin-treated RHCT116 p53-/- cells but increasing basal- and oxaliplatin-induced PEA3 and MMP7 in the HT29 and RHT29 cells., Conclusions: Oxaliplatin-induced MMP7 up-regulation is differentially achieved in colon cancer cell lines, as a result of EGFR and β-catenin cross-talk on MMP7 gene transcription. Taken together, our results point out the disparity of effects that β-catenin and EGFR blocking therapeutic strategies may exert on MMP7 expression depending on the cellular context and remark the importance of a better knowledge of MMP7 regulation to improve chemotherapy effectiveness in colon cancer.

G protein-coupled receptors (GPCRs) comprise a large family of membrane receptors involved in signal transduction. These receptors are linked to a variety of physiological and biological processes such as regulation of neurotransmission, growth, cell differentiation and oncogenesis among others. Some of the effects of GPCRs are known to be mediated by the activation of MAPK pathways. Several GPCRs are also able to transactivate receptors with tyrosine kinase activity (TKR) such as EGFR and HER2 and thus to control DNA synthesis and cell proliferation. The interaction between these receptors not only plays an important physiological role but its disregulation can induce pathological states such as cancer. For this reason, the crosstalk between these two types of receptors can be considered a possible mechanism for cell transformation, tumor progression, reactivation of the metastatic disease, and the acquisition of resistance to therapies targeting TKR receptors. The transactivation of some TKRs by GPCRs is related to the lost of response of TKRs to inhibitors of TK activity, mainly by the activation of the c-Src protein which can directly phosphorylate and activate the cytoplasmic domain of a TKR. For these reason, the dual inhibition of GPCRs and TKRs in some types of cancer has been proposed as a better strategy to kill tumor cells. Increased understanding of the mechanisms that interconnect the two pathways regulated by GPCRs and TKRs may facilitate the design of new therapeutic strategies.

Background: CD95 is a death receptor controlling not only apoptotic pathways but also activating mechanisms promoting tumor growth. During the acquisition of chemoresistance to oxaliplatin there is a progressive loss of CD95 expression in colon cancer cells and a decreased ability of this receptor to induce cell death. The aim of this study was to characterize some key cellular responses controlled by CD95 signaling in oxaliplatin-resistant colon cancer cells., Results: We show that CD95 triggering results in an increased metastatic ability in resistant cells. Moreover, oxaliplatin treatment itself stimulates cell migration and decreases cell adhesion through CD95 activation, since CD95 expression inhibition by siRNA blocks the promigratory effects of oxaliplatin. These promigratory effects are related to the epithelia-to-mesenchymal transition (EMT) phenomenon, as evidenced by the up-regulation of some transcription factors and mesenchymal markers both in vitro and in vivo., Conclusions: We conclude that oxaliplatin treatment in cells that have acquired resistance to oxaliplatin-induced apoptosis results in tumor-promoting effects through the activation of CD95 signaling and by inducing EMT, all these events jointly contributing to a metastatic phenotype.

Background: The efficacy of oxaliplatin in cancer chemotherapy is limited by the development of drug resistance. MMP7 has been related to the loss of tumor cell response to cytotoxic agents although the exact mechanism is not fully understood. Moreover, MMP7 is an independent prognosis factor for survival in patients with colorectal cancer. The aim of the present study was to analyze the role of MMP7 and its cross-talk with the Fas/FasL system during the acquisition of oxaliplatin resistance in colon cancer cells., Principal Findings: For this purpose we have developed three different oxaliplatin-resistant cell lines (RHT29, RHCT116 p53(+/+), RHCT116 p53(-/-)) from the parental HT29, HCT116 p53(+/+) and HCT116 p53(-/-) colon cancer cells. MMP7 basal expression was higher in the resistant compared to the parental cell lines. MMP7 was also upregulated by oxaliplatin in both HT29 (p53 mutant) and RHCT116 p53(-/-) but not in the RHCT116 p53(+/+). Inhibition of MMP by 1,10-phenantroline monohydrate or siRNA of MMP7 restores cell sensitivity to oxaliplatin-induced apoptosis in both HT29 and RHCT116 p53(-/-) but not in the RHCT116 p53(+/+). Some of these effects are caused by alterations in Fas receptor. Fas is upregulated by oxaliplatin in colon cancer cells, however the RHT29 cells treated with oxaliplatin showed a 3.8-fold lower Fas expression at the cell surface than the HT29 cells. Decrease of Fas at the plasma membrane seems to be caused by MMP7 since its inhibition restores Fas levels. Moreover, functional analysis of Fas demonstrates that this receptor was less potent in inducing apoptosis in RHT29 cells and that its activation induces MAPK signaling in resistant cells., Conclusions: Taking together, these results suggest that MMP7 is related to the acquisition of oxaliplatin-resistance and that its inhibition restores drug sensitivity by increasing Fas receptor. Furthermore, Fas undergoes a change in its functionality in oxaliplatin-resistant cells inducing survival pathways instead of apoptotic signals.