Impact of sunitinib resistance on clear cell renal cell carcinoma therapeutic sensitivity in vitro

Sunitinib resistance creates a major clinical challenge for the treatment of advanced clear cell renal cell carcinoma (ccRCC) and functional and metabolic changes linked to sunitinib resistance are not fully understood. We sought to characterize the molecular and metabolic changes induced by the development of sunitinib resistance in ccRCC by developing and characterizing two human ccRCC cell lines resistant to sunitinib. Consistent with the literature, sunitinib-resistant ccRCC cell lines presented an aberrant overexpression of Axl and PD-L1, as well as a metabolic rewiring characterized by enhanced OXPHOS and glutamine metabolism. Therapeutic challenges of sunitinib-resistant ccRCC cell lines in vitro using small molecule inhibitors targeting Axl, AMPK and p38, as well as using PD-L1 blocking therapeutic antibodies, showed limited CTL-mediated cytotoxicity in a co-culture model. However, the AMPK activator metformin appears to sensitize the effect of PD-L1 blocking therapeutic antibodies and to enhance CTLs' cytotoxic effects on ccRCC cells. These effects were not broadly observed with the Axl and the p38 inhibitors. Taken together, these data suggest that targeting certain pathways aberrantly activated by sunitinib resistance such as the AMPK/PDL1 axis might sensitize ccRCC to immunotherapies as a second-line therapeutic approach.

The evolving use of pembrolizumab in combination treatment approaches for non-small cell lung cancer

Introduction: The immune checkpoint inhibitor, pembrolizumab, has revolutionized the treatment of non-small cell lung cancer (NSCLC). It is currently approved and widely used in patients with advanced NSCLC whose tumors have no EGFR or ALK genomic aberrations that express PD-L1 as single-agent treatment and irrespective of PD-L1 expression in combination with platinum-based doublet chemotherapy in the first-line setting.Areas covered: The authors have reviewed articles discussing pembrolizumab and NSCLC in MEDLINE between July 2013 to August 2019 and focus on recent advances in combining pembrolizumab with chemotherapy, radiotherapy and other novel agents in various stages of NSCLC.Expert opinion: Although pembrolizumab has revolutionized the treatment of advanced NSCLC, only a subset of patients benefit from single-agent therapy. Numerous trials combining pembrolizumab with chemotherapy and radiation have shown benefit and a large spectrum of novel combination strategies are being explored for improved synergies. In addition to PD-L1 tumor proportion score, validation of other biomarkers would be beneficial in stratifying patients and improving the predictive value of combining immune check point inhibitors and chemotherapy.