Carcinoma-associated fibroblasts affect sensitivity to oxaliplatin and 5FU in colorectal cancer cells

// Samuel Gonçalves-Ribeiro 1 , Natalia Guillen Díaz-Maroto 1 , Mireia Berdiel-Acer 1 , Antonio Soriano 2 , Jordi Guardiola 2 , Mercedes Martínez-Villacampa 3 , Ramon Salazar 3 , Gabriel Capellà 4 , Alberto Villanueva 1 , Eva Martínez-Balibrea 5 , David G. Molleví 1 1 Program Against Cancer Therapeutic Resistance, Catalan Institute of Oncology, IDIBELL, L’Hospitalet de Llobregat, Catalonia, Spain 2 Gastroenterology Department, Endoscopy Unit, Hospital Universitari de Bellvitge, IDIBELL, L’Hospitalet de Llobregat, Catalonia, Spain 3 Medical Oncology Department, Catalan Institute of Oncology, IDIBELL, L’Hospitalet de Llobregat, Catalonia, Spain 4 Hereditary Cancer Program, Catalan Institute of Oncology, IDIBELL, L’Hospitalet de Llobregat, Catalonia, Spain 5 Program Against Cancer Therapeutic Resistance, Catalan Institute of Oncology, IGTP, Badalona, Catalonia, Spain Correspondence to: David G. Molleví, email: dgmollevi@iconcologia.net Keywords: carcinoma-associated fibroblasts, microenvironment-mediated drug resistance, colorectal cancer, resistance, chemotherapy Received: May 11, 2016     Accepted: July 19, 2016     Published: August 08, 2016 ABSTRACT The importance of tumor microenvironment (TME) as a relevant contributor to cancer progression and its role in the development of de novo resistance to targeted therapies has become increasingly apparent. However, the mechanisms of microenvironment-mediated drug resistance for nonspecific conventional chemotherapeutic agents, such as platinum compounds or antimetabolites, are still unclear. Here we describe a mechanism induced by soluble factors released by carcinoma-associated fibroblasts (CAFs) that induce the translocation of AKT, Survivin and P38 to the nucleus of tumor cells. These changes are guided to ensure DNA repair and the correct entrance and exit from mitosis in the presence of chemotherapy. We used conditioned media (CM) from normal-colonic fibroblasts and paired CAFs to assess dose response curves of oxaliplatin and 5-fluorouracil, separately or combined, compared with standard culture medium. We also evaluated a colony-forming assay and cell death to demonstrate the protective role of CAF-CM. Immunofluorescence confirmed the translocation of AKT, P38 and Survivin to the nucleus induced by CAF-soluble factors. We also have shown that STAT3 or P38 inhibition provides a promising strategy for overcoming microenvironment-mediated resistance. Conversely, pharmacologic AKT inhibition induces an antagonistic effect that relieves a cMET and STAT3-mediated compensatory feedback that might explain the failure of AKT inhibitors in the clinic so far.