ELR+CXCL Cytokines in Metastatic Kidney Cancers: Predictive Markers of Resistance to Sunitinib

Metastatic renal cell carcinomas (mRCC) are highly angiogenic tumors because of mutation of the pVHL gene leading to over-expression of VEGF. Therefore, mRCC represent a paradigm for the use of anti-angiogenic treatments targeting the VEGF/VEGFR pathway. Despite an increase of the time to progression these treatments, taken alone, are not curative with ineluctable progression especially for the reference treatment sunitinib a multi kinase inhibitors of VEGF, PDGF, CSF1 receptors and c-kit, FLT3 and RET. At progression on sunitinib, patients received mTOR inhibitors which is responsible, at least, of HIF1A mRNA translation, then on a third line sorafenib that inhibits VEGFR2, 3 PDGFR, c-KIT and B-RAF. The access to these different lines of treatment has finally prolonged survival but this situation is not satisfactory. Unexpected aspect associated with the use of anti-angiogenesis treatments was the diversity of the patients' response. Some patients are right away refractory and die rapidly, but the majority of patient has a transient response then progress and a few percentages of them are responder for a very long period of time. By only targeting normal endothelial cells and tumor neo-vascularization, the response should have been more homogenous, thus highlighting that the treatment induced a "Darwinian" adaptation of tumor cells and cells of the microenvironment. Two conclusions follow from these observations: 1- The need to identify predictive markers of efficacy; 2-The identification of druggable targets participating in progression on anti-angiogenic treatments. Our results have highlighted the ELR+CXCL cytokines, pro-inflammatory and pro-angiogenic cytokines as prognosis markers of survival of mRCC patients and relevant therapeutic targets on experimental tumors in mice. As VEGF/VEGFR, these cytokines are produced by tumor, endothelial and inflammatory cells. Their receptors (CXCR1, 2) are expressed physiologically by immune and endothelial cells and aberran