Spinophilin loss correlates with poor patient prognosis in advanced stages of colon carcinoma

[Purpose+ The genomic region 17q21 is frequently associated with microsatellite instability and LOH in cancer, including gastric and colorectal carcinomas. This region contains several putative tumor suppressor genes, including Brca1, NM23, prohibitin, and spinophilin (Spn, PPP1R9B, neurabin II). The scaffold protein Spn is one of the regulatory subunits of phosphatase-1 (PP1) that targets PP1 to distinct subcellular locations and couples PP1 to its target. Thus, Spn may alter cell-cycle progression via the regulation of the phosphorylation status of the retinoblastoma protein, a direct target of PP1. Therefore, we analyzed whether Spn levels were reduced in colorectal carcinomas and whether Spn levels correlated with prognosis or response to therapy.[Experimental Design] By means of immunohistochemistry or quantitative PCR, we studied the levels of Spn in stages II, III, and IV colorectal carcinoma tumors and correlated to other clinicopathologic features as well as prognosis or response to therapy.[Results] Spn was lost in a percentage of human gastric, small intestine, and colorectal carcinomas. In patients with colorectal carcinoma, tumoral Spn downregulation correlated with a more aggressive histologic phenotype (poorer tumor differentiation and higher proliferative Ki67 index). Consistent with this observation, lower Spn protein expression levels were associated with faster relapse and poorer survival in patients with stage III colorectal carcinoma, particularly among those receiving adjuvant fluoropyrimidine therapy. We validated this result in an independent cohort of patients with metastatic colorectal carcinoma treated with standard chemotherapy. Although patients that achieved an objective tumor response exhibited Spn levels similar to nontumoral tissue, nonresponding patients showed a significant reduction in Spn mRNA levels.[Conclusions] Our data suggest that Spn downregulation contributes to a more aggressive biologic behavior, induces chemoresistance, and is associated with a poorer survival in patients with advanced stages of colorectal carcinoma. © 2013 American Association for Cancer Research.This work was supported by grants from the Spanish Ministry of Science and Innovation (SAF2009-08605), Fondo de Investigacion Sanitaria (PI12/00137), Consejeria de Ciencia e Innovacion, and Consejeria de Salud of the Junta de Andalucia (CTS-6844 and PI-0142). A. Carnero's laboratory is also funded by a fellowship from Fundacion Oncologica FERO. P. Estevez-Garcia and I. Lopez-Calderero are supported by Rio Ortega Fellowships and S. Molina-Pinelo is supported by a Sara Borrell fellowship. R. Garcia-Carbonero is funded by the Instituto de Salud Carlos III, Ministerio de Sanidad, Spain (PI 10.02164).Peer Reviewe

PDGFR / and VEGFR2 polymorphisms in colorectal cancer: incidence and implications in clinical outcome

Abstract Background Angiogenesis plays an essential role in tumor growth and metastasis, and is a major target in cancer therapy. VEGFR and PDGFR are key players involved in this process. The purpose of this study was to assess the incidence of genetic variants in these receptors and its potential clinical implications in colorectal cancer (CRC). Methods VEGFR2, PDGFRα and PDGFRβ mutations were evaluated by sequencing their tyrosine kinase domains in 8 CRC cell lines and in 92 samples of patients with CRC. Correlations with clinicopathological features and survival were analyzed. Results Four SNPs were identified, three in PDGFRα [exon 12 (A12): c.1701A>G; exon 13 (A13): c.1809G>A; and exon 17 (A17): c.2439+58C>A] and one in PDGFRβ [exon 19 (B19): c.2601A>G]. SNP B19, identified in 58% of tumor samples and in 4 cell lines (LS174T, LS180, SW48, COLO205), was associated with higher PDGFR and pPDGFR protein levels. Consistent with this observation, 5-year survival was greater for patients with PDGFR B19 wild type tumors (AA) than for those harboring the G-allele genotype (GA or GG) (51% vs 17%; p=0.073). Multivariate analysis confirmed SNP B19 (p=0.029) was a significant prognostic factor for survival, independent of age (p=0.060) or TNM stage (pG SNP is commonly encountered in CRC patients and is associated with increased pathway activation and poorer survival. Implications regarding its potential influence in response to PDGFR-targeted agents remain to be elucidated.This work was supported by a grant of the Ministerio de Ciencia y Tecnologia of Spain (FIT-010000-2006-45). PEG is funded by a Rio Hortega grant (09/00207) from the Instituto de Salud Carlos III (ISCiii), Ministerio de Sanidad, Spain. SMP is funded by the ISCiii (CD1100153), Fundación Científica de la Asociacion Española Contra el Cancer (AECC), Consejeria de Salud – Junta de Andalucia (PI-0224/2009) and Fundacion Mutua Madrileña (2009). MDP is funded by the ISCiii (CD0900148). LPA is funded by the ISCiii (PI081156 and PI1102688), Consejería de Innovacion, Ciencia y Empresa – Junta de Andalucia (P08-CVI-04090) and the 75th Anniversary Roche Spain Fellowship. RGC is funded by the ISCiii (PI 10.02164).Peer Reviewe

Prognostic relevance of estrogen receptor-alpha Ser167 phosphorylation in stage II-III colon cancer patients

Preclinical and clinical data suggest a protective role for estrogens on colon cancer (CRC) risk. estrogen receptor (ER) β is the prevalent ER in normal colonic mucosa, whereas its expression is significantly reduced in CRC. An increased ERα/β ratio has been documented in colon carcinomas and is associated with increased proliferation and decreased apoptosis. The aim of our study was to evaluate the expression of activated ERα and its prognostic implications in patients with stage II-III CRC. Phospho-ERαSer167 (pERαSer167) expression was assessed by immunohistochemistry in 218 CRC paraffin-embedded tumor samples. A high pERαSer167 expression was more commonly observed in women, older patients, and patients with high baseline glucose levels. This higher pERαSer167 expression was associated with decreased 5-year disease-free interval (DFI; 66% versus 78%, P = .07) and overall survival (65% versus 73%, P = .46). The negative impact of high pERαSer167 expression on DFI was particularly significant (P < .05) in women (85% versus 60%), young (82% versus 61%), nondiabetic (85% versus 66%), and stage II patients (86% versus 72% and low versus high pERαSer167, respectively). Multivariate analysis confirmed that pERαSer167 score was a significant prognostic factor for both DFI and overall survival, independent of sex, age, glucose levels, tumor stage, bowel obstruction/perforation, or adjuvant chemotherapy. These findings illustrate the relevance of estrogen pathways in colon cancer biology and may provide novel therapeutic avenues to be explored in this context.The authors would like to thank the donors and the Andalusian Public Health System Biobank Network (ISCIII-Red de Biobancos RD09/0076/00085) for the human tumor specimens provided for this study.Peer Reviewe

Phase I clinical and pharmacokinetic study of PM01183 (a tetrahydroisoquinoline, Lurbinectedin) in combination with gemcitabine in patients with advanced solid tumors.

Background To determine the recommended dose (RD) of a combination of PM01183 and gemcitabine in patients with advanced solid tumors. Methods Forty-five patients received escalating doses of PM01183/gemcitabine on Days 1 and 8 every 3 weeks (d1,8 q3wk) following a standard 3 + 3 design. Results PM01183 3.5 mg flat dose (FD)/gemcitabine 1000 mg/m2 was the highest dose level tested. Dose-limiting toxicities (DLTs) were mostly hematological and resulted in the expansion of a lower dose level (PM01183 3.5 mg FD/gemcitabine 800 mg/m2); 19 patients at this dose level were evaluable but >30% had DLT and >20% had febrile neutropenia. No DLT was observed in 11 patients treated at PM01183 3.0 mg FD/gemcitabine 800 mg/m2, which was defined as the RD. This regimen was feasible and tolerable with manageable toxicity; mainly grade 3/4 myelosuppression. Non-hematological toxicity comprised fatigue, nausea, vomiting, and transaminases increases. Fifteen (33%) patients received ≥6 cycles with no cumulative hematological toxicity. Pharmacokinetic analysis showed no evidence of drug-drug interaction. Nine of 38 patients had response as per RECIST (complete [3%] and partial [21%]), for an overall response rate (ORR) of 24% (95% Confidence Interval [CI] 12-40%). Eleven patients (29%) had disease stabilization ≥4 months. Responses were durable (median of 8.5 months): overall median progression-free survival (PFS) was 4.2 months (95% CI, 2.7-6.5 months). Conclusions The RD for this combination is PM01183 3.0 mg FD (or 1.6 mg/m2)/gemcitabine 800 mg/m2 d1,8 q3wk. This schedule is well tolerated and has antitumor activity in several advanced solid tumor types