RNAi screen reveals synthetic lethality between cyclin G-associated kinase and FBXW7 by inducing aberrant mitoses.

BACKGROUND: F-box and WD40 repeat domain-containing 7 (FBXW7) is an E3 ubiquitin ligase involved in the ubiquitination and degradation of multiple oncogenic substrates. The tumour suppressor function is frequently lost in multiple cancers through genetic deletion and mutations in a broad range of tumours. Loss of FBXW7 functionality results in the stabilisation of multiple major oncoproteins, culminating in increased cellular proliferation and pro-survival pathways, cell cycle deregulation, chromosomal instability and altered metabolism. Currently, there is no therapy to specifically target FBXW7-deficient tumours. METHODS: We performed a siRNA kinome screen to identify synthetically lethal hits to FBXW7 deficiency. RESULTS: We identified and validated cyclin G-associated kinase (GAK) as a potential new therapeutic target. Combined loss of FBXW7 and GAK caused cell cycle defects, formation of multipolar mitoses and the induction of apoptosis. The synthetic lethal mechanism appears to be independent of clathrin-mediated receptor endocytosis function of GAK. CONCLUSIONS: These data suggest a putative therapeutic strategy for a large number of different types of human cancers with FBXW7 loss, many of which have a paucity of molecular abnormalities and treatment options.

Indolent peritoneal mesothelioma: PI3K-mTOR inhibitors as a novel therapeutic strategy.

Peritoneal mesothelioma (MPeM) is a scarce abdominal-pelvic malignancy that presents with non-specific features and exhibits a wide clinical spectrum from indolent to aggressive disease. Due to it being a rare entity, there is a lack of understanding of its molecular drivers. Most treatment data are from limited small studies or extrapolated from pleural mesothelioma. Standard treatment includes curative surgery or pemetrexed-platinum palliative chemotherapy. To date, the use of novel targeted agents has been disappointing. Described is the management of two young women with papillary peritoneal mesothelioma with widespread recurrence having received platinum-pemetrexed chemotherapy. Both patients obtained symptomatic and disease benefit with apitolisib, a dual phosphoinositide 3-kinase-mammalian target of rapamycin (PI3K-mTOR) inhibitor for subsequent relapses, with one patient having a partial response for almost 3 years. Both are alive and well 10-13 years from diagnosis. CONCLUSION: These case presentations highlight a subgroup of rare MPeM that behave indolently that is compatible with long-term survival. This series identifies the use of targeted therapies with PI3K-mTOR-based inhibitors as a novel approach, warranting further clinical assessment. Development of prognostic biomarkers is essential to aid identify tumour aggressiveness, help stratify patients and facilitate treatment decisions.

Advances in the Development of Molecularly Targeted Agents in Non-Small-Cell Lung Cancer.

Non-small-cell lung cancer (NSCLC) remains a significant global health challenge and the leading cause of cancer-related mortality. The traditional 'one-size-fits-all' treatment approach has now evolved into one that involves personalized strategies based on histological and molecular subtypes. The molecular era has revolutionized the treatment of patients harboring epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK) and ROS1 gene aberrations. In the appropriately selected population, anti-tumor agents against these molecular targets can significantly improve progression-free survival. However, the emergence of acquired resistance is inevitable. Novel potent compounds with much improved and rational selectivity profiles, such as third-generation EGFR T790M resistance mutation-specific inhibitors, have been developed and added to the NSCLC armamentarium. To date, attempts to overcome resistance bypass pathways through downstream signaling blockade has had limited success. Furthermore, the majority of patients still do not harbor known driver genetic or epigenetic alterations and/or have no new available treatment options, with chemotherapy remaining their standard of care. Several potentially actionable driver aberrations have recently been identified, with the early clinical development of multiple inhibitors against these promising targets currently in progress. The advent of immune checkpoint inhibitors has led to significant benefit for advanced NSCLC patients with durable responses observed. Further interrogation of the underlying biology of NSCLC, coupled with modern clinical trial designs, is now required to develop novel targeted therapeutics rationally matched with predictive biomarkers of response, so as to further advance NSCLC therapeutics through the next decade.

A study of motivations and expectations of patients seen in phase 1 oncology clinics.

BACKGROUND: To better inform clinical practice, this study was aimed at capturing patients' motivations for enrolling in phase 1 trials and at quantifying their expectations of the benefits, risks, and commitment associated with clinical trials and the impact of the initial consultation on their expectations. METHODS: This was a single-center, prospective, quantitative study of newly referred adult patients considering their first phase 1 oncology trial. Participants completed questionnaires before they were seen and an abbreviated follow-up version after their consultation. RESULTS: Questionnaires were completed by 396 (99%) and 301 (76%) before and after the clinic, respectively. Participants ranked the possibility of tumor shrinkage (84%) as the most important motivation for considering a phase 1 trial; this was followed by no alternative treatments (56%), their physician's recommendation (44%), and the fact that the research might benefit others (38%). When they were asked about the potential personal benefit, 43% predicted tumor shrinkage initially. After the consultation, this increased to 47%. Fourteen percent of patients expected a cure. When asked about risks, 71% of the participants expected moderate side effects. When asked about expectations of time commitments, a majority of patients did not anticipate weekly visits, although this was understood by 93% of patients after the consultation. Overall, patients were keen to consider trials and when asked before and after the consultation 72% and 84% were willing to enroll in studies, respectively. CONCLUSIONS: This study reports that more than 80% of patients enroll in early-phase clinical oncology trials motivated by the potential of a clinical benefit, with approximately half expecting tumor shrinkage and approximately a tenth anticipating a cure. The typical phase 1 response rate is 4% to 20%, and this discrepancy exemplifies the challenges faced by patients and healthcare professionals during their interactions for phase 1 studies. Cancer 2016;122:3501-3508. © 2016 American Cancer Society.

Phase I Study of Apitolisib (GDC-0980), Dual Phosphatidylinositol-3-Kinase and Mammalian Target of Rapamycin Kinase Inhibitor, in Patients with Advanced Solid Tumors.

PURPOSE: This first-in-human phase I trial assessed the safety, tolerability, and preliminary antitumor activity of apitolisib (GDC-0980), a dual inhibitor of class I PI3K, and mTOR kinases. EXPERIMENTAL DESIGN: Once-daily oral apitolisib was administered to patients with solid tumors for days 1 to 21 or 1 to 28 of 28-day cycles. Pharmacokinetic and pharmacodynamic parameters were assessed. RESULTS: Overall, 120 patients were treated at doses between 2 and 70 mg. The commonest ≥G3 toxicities related to apitolisib at the recommended phase 2 dose (RP2D) at 40 mg once daily included hyperglycemia (18%), rash (14%), liver dysfunction (12%), diarrhea (10%), pneumonitis (8%), mucosal inflammation (6%), and fatigue (4%). Dose-limiting toxicities (1 patient each) were G4 fasting hyperglycemia at 40 mg (21/28 schedule) and G3 maculopapular rash and G3 fasting hyperglycemia at 70 mg (21/28 schedule). The pharmacokinetic profile was dose-proportional. Phosphorylated serine-473 AKT levels were suppressed by ≥90% in platelet-rich plasma within 4 hours at the MTD (50 mg). Pharmacodynamic decreases in fluorodeoxyglucose positron emission tomography uptake of >25% occurred in 66% (21/32) of patients dosed at 40 mg once daily. Evidence of single-agent activity included 10 RECIST partial responses (PR; confirmed for peritoneal mesothelioma, PIK3CA mutant head-and-neck cancer, and three pleural mesotheliomas). CONCLUSIONS: Apitolisib exhibited dose-proportional pharmacokinetics with target modulation at doses ≥16 mg. The RP2D was 40 mg once-daily 28/28 schedule; severe on-target toxicities were apparent at ≥40 mg, particularly pneumonitis. Apitolisib was reasonably tolerated at 30 mg, the selected dose for pleural mesothelioma patients given limited respiratory reserve. Modest but durable antitumor activity was demonstrated. Clin Cancer Res; 22(12); 2874-84. ©2016 AACR.

Factor H, a regulator of complement activity, is a major determinant of meningococcal disease susceptibility in UK Caucasian patients.

Defence against Neisseria meningitidis involves complement-mediated bactericidal activity. Factor H (fH) down-regulates complement activation. A putatively functional single-nucleotide-polymorphism (SNP) exists within a presumed nuclear-factor-kappa-B responsive element (NF-kB) in the fH gene (C-496T). Genetic and functional investigations were carried out to determine whether C-496T has a role in meningococcal disease (MD) susceptibility. Genetic susceptibility was investigated in 2 independent studies, a case-control and family-based transmission-disequilibrium-test (TDT), using 2 separate cohorts of UK Caucasian patients. MD susceptibility was both genetically associated with the C/C homozygous genotype (OR = 2.0, 95% CI 1.3 - 3.2, p = 0.001) and linked to the C allele (p = 0.04), the association being most significant in serogroup C infected patients (OR = 2.9, 95% CI 1.6 - 5.5, p = 0.0002). FH serum concentrations were also associated with C-496T genotype, with highest fH concentrations in C/C homozygous individuals (p = 0.01). Functional studies showed NF-kappa-B binding to the C-496T-containing region and that pre-incubation of fH with meningococci reduced bactericidal activity and increased meningococci B and C survival in blood. This study shows that C-496T is both associated and linked with MD and that individuals possessing the fH C-496T C/C genotype are more likely to have increased serum fH protein levels, have reduced bactericidal activity against meningococci and be at an increased risk of contracting MD.