The Impact of Concomitant Proton Pump Inhibitors on Immunotherapy Efficacy Among Patients with Urothelial Carcinoma: A Meta-Analysis

Background. Immune checkpoint inhibitors (ICIs) have recently represented a breakthrough in urothelial carcinoma (UC). Proton pump inhibitors (PPIs) are routinely used for extended time periods in UC patients, with these agents having potentially and frequently undervalued effects on ICIs efficacy. Methods. We performed a meta-analysis aimed at investigating the impact of concomitant PPI administration on progression-free survival (PFS) and overall survival (OS) among patients receiving immunotherapy for metastatic UC. Results. Two studies encompassing a total of 1015 patients were included. The pooled Hazard Ratios (HRs) for OS and PFS were 1.55 (95% CI, 1.31–1.84) and 1.43 (95% CI, 1.23–1.66), respectively, suggesting that the administration of PPIs was negatively associated with PFS and with OS in UC patients treated with ICIs. Conclusions. The current meta-analysis represents the first study to provide a systematic evaluation of the impact of concomitant PPI use in UC patients treated with ICIs. Further studies are warranted on this topic to clarify the relationship between gut microbiome, antiacid exposure, and cancer immunotherapy. In the current era of medical oncology, progress in this setting will require the collaboration of basic science and clinical research to optimize systemic treatment and to improve the outcomes of UC patients receiving ICIs

Pan-RAF and MEK vertical inhibition enhances therapeutic response in non-V600 BRAF mutant cells

BACKGROUND: Currently, there are no available targeted therapy options for non-V600 BRAF mutated tumors. The aim of this study was to investigate the effects of RAF and MEK concurrent inhibition on tumor growth, migration, signaling and apoptosis induction in preclinical models of non-V600 BRAF mutant tumor cell lines. METHODS: Six BRAF mutated human tumor cell lines CRL5885 (G466 V), WM3629 (D594G), WM3670 (G469E), MDAMB231 (G464 V), CRL5922 (L597 V) and A375 (V600E as control) were investigated. Pan-RAF inhibitor (sorafenib or AZ628) and MEK inhibitor (selumetinib) or their combination were used in in vitro viability, video microscopy, immunoblot, cell cycle and TUNEL assays. The in vivo effects of the drugs were assessed in an orthotopic NSG mouse breast cancer model. RESULTS: All cell lines showed a significant growth inhibition with synergism in the sorafenib/AZ628 and selumetinib combination. Combination treatment resulted in higher Erk1/2 inhibition and in increased induction of apoptosis when compared to single agent treatments. However, single selumetinib treatment could cause adverse therapeutic effects, like increased cell migration in certain cells, selumetinib and sorafenib combination treatment lowered migratory capacity in all the cell lines. Importantly, combination resulted in significantly increased tumor growth inhibition in orthotropic xenografts of MDAMB231 cells when compared to sorafenib - but not to selumetinib - treatment. CONCLUSIONS: Our data suggests that combined blocking of RAF and MEK may achieve increased therapeutic response in non-V600 BRAF mutant tumors

AMP-activated protein kinase - not just an energy sensor

Orthologues of AMP-activated protein kinase (AMPK) occur in essentially all eukaryotes as heterotrimeric complexes comprising catalytic α subunits and regulatory β and γ subunits. The canonical role of AMPK is as an energy sensor, monitoring levels of the nucleotides AMP, ADP, and ATP that bind competitively to the γ subunit. Once activated, AMPK acts to restore energy homeostasis by switching on alternate ATP-generating catabolic pathways while switching off ATP-consuming anabolic pathways. However, its ancestral role in unicellular eukaryotes may have been in sensing of glucose rather than energy. In this article, we discuss a few interesting recent developments in the AMPK field. Firstly, we review recent findings on the canonical pathway by which AMPK is regulated by adenine nucleotides. Secondly, AMPK is now known to be activated in mammalian cells by glucose starvation by a mechanism that occurs in the absence of changes in adenine nucleotides, involving the formation of complexes with Axin and LKB1 on the surface of the lysosome. Thirdly, in addition to containing the nucleotide-binding sites on the γ subunits, AMPK heterotrimers contain a site for binding of allosteric activators termed the allosteric drug and metabolite (ADaM) site. A large number of synthetic activators, some of which show promise as hypoglycaemic agents in pre-clinical studies, have now been shown to bind there. Fourthly, some kinase inhibitors paradoxically activate AMPK, including one (SU6656) that binds in the catalytic site. Finally, although downstream targets originally identified for AMPK were mainly concerned with metabolism, recently identified targets have roles in such diverse areas as mitochondrial fission, integrity of epithelial cell layers, and angiogenesis

The inhibition of FGF receptor 1 activity mediates sorafenib-induced antiproliferative effects in human mesothelioma tumor-initiating cells

Tumor-initiating cells (TICs), the subset of cells within tumors endowed with stem-like features, being highly resistant to conventional cytotoxic drugs, are the major cause of tumor relapse. The identification of molecules able to target TICs remains a significant challenge in cancer therapy. Using TIC-enriched cultures (MM1, MM3 and MM4), from 3 human malignant pleural mesotheliomas (MPM), we tested the effects of sorafenib on cell survival and the intracellular mechanisms involved. Sorafenib inhibited cell-cycle progression in all the TIC cultures, but only in MM3 and MM4 cells this effect was associated with induction of apoptosis via the down-regulation of Mcl-1. Although sorafenib inhibits the activity of several tyrosine kinases, its effects are mainly ascribed to Raf inhibition. To investigate the mechanisms of sorafenib-mediated antiproliferative activity, TICs were treated with EGF or bFGF causing, in MM3 and MM4 cells, MEK, ERK1/2, Akt and STAT3 phosphorylation. These effects were significantly reduced by sorafenib in bFGF-treated cells, while a slight inhibition occurred after EGF stimulation, suggesting that sorafenib effects are mainly due to FGFR inhibition. Indeed, FGFR1 phosphorylation was inhibited by sorafenib. A different picture was observed in MM1 cells, which, releasing high levels of bFGF, showed an autocrine activation of FGFR1 and a constitutive phosphorylation/activation of MEK-ERK1/2. A powerful inhibitory response to sorafenib was observed in these cells, indirectly confirming the central role of sorafenib as FGFR inhibitor. These results suggest that bFGF signaling may impact antiproliferative response to sorafenib of MPM TICs, which is mainly mediated by a direct FGFR targeting

First-line immune checkpoint inhibitor-based combinations in unresectable hepatocellular carcinoma: current management and future challenges

Introduction: Immunotherapy has recently taken on an extremely important role in medical oncology, as first- or later-line treatment in several tumor types, and recent years have seen the emerging of clinical trials assessing immune checkpoint inhibitors (ICIs) in unresectable hepatocellular carcinoma (HCC). Areas Covered: Herein, we provide an overview of recently published studies exploring the dual immune checkpoint blockade or the combination of ICIs plus biological treatments as first-line treatment in HCC patients with advanced disease, especially focusing on the biological rationale behind these therapeutic strategies, and ongoing active and recruiting clinical trials. Expert Opinion: Results of studies on monotherapy with ICIs have suggested that this strategy could be beneficial only in a minority of patients; conversely, the recently published IMbrave150 study has reported an overall survival benefit in HCC receiving the combination of atezolizumab plus bevacizumab compared to sorafenib as first-line treatment. A wide number of clinical trials is evaluating ICI-based combinations in advanced HCC, a strategy which is supported by robust preclinical and early-phase clinical data, and results of these studies are highly awaited

Sorafenib (BAY 43-9006) in hepatoccellular carcinoma patients: from discovery to clinical development.

Angiogenesis and signaling through the RASlRAF/mitogen-activated protein/extracellular signal-regulated kinase (ERK) kinase (MEK)/ERKcascade have been reported to play important roles in the development of hepatocellular carcinoma (HCC). Sorafenib (Nexavar), a novel bi-aryl urea SAY 43-9006, is an orally administered multikinase inhibitor with activity against RASIRAF kinases multikinase inhibitor with activity against RAP kinases and several receptor tyrosine kinases, including vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (pDGFR), FLT3, Ret, and c-Kit. It is involved in angiogenic pathway and cell proliferation. Sorafenib has demonstrated potent anti-tumor activity in in vitro studies, preclinical xenograft models of different tumor types and human clinical trials. This review summarizes the history of sorafenib from its discovery by the medicinal chemistry approach through to clinical development and ongoing trials on the combination between sorafenib and trans-arterial chemoembolization (TACE) in HCC patients