Effect of social capital, social support and social network formation on the quality of life of American adults during COVID-19

This study aims to evaluate the effect of social capital (SC), social support (SS), and social network formation (SNF) on the quality of life of American adults during COVID-19. Using a probability sample of American adults aged 49+, 2370 respondents were selected from the National Social Life Health and Aging Project (NSHAP) dataset for analysis using an integrated partial least squares based on structural equation modeling (PLS-SEM)-K-fold cross-validation approach. The analysis showed that social capital assessed using civic engagement, social cohesion, socioeconomic status (SES), social support, and social network formation were significantly and positively associated with American adults' quality of life during the COVID-19 pandemic. Furthermore, the results showed that using the PLS-SEM and K-fold cross-validation approach produced a medium predictive power of the overall model, confirming the importance of SC, SS, and SNF in predicting quality of life-outcomes. These findings suggest that efforts to promote the well-being of American adults, especially older adults, during the pandemic should focus on strengthening social capital, social support and social network formation.

The paradox-breaking panRAF plus SRC family kinase inhibitor, CCT3833, is effective in mutant KRAS-driven cancers

BACKGROUND

KRAS is mutated in ∼90% of pancreatic ductal adenocarcinomas, ∼35% of colorectal cancers and ∼20% of non-small-cell lung cancers. There has been recent progress in targeting G12CKRAS specifically, but therapeutic options for other mutant forms of KRAS are limited, largely because the complexity of downstream signaling and feedback mechanisms mean that targeting individual pathway components is ineffective.

DESIGN

The protein kinases RAF and SRC are validated therapeutic targets in KRAS-mutant pancreatic ductal adenocarcinomas, colorectal cancers and non-small-cell lung cancers and we show that both must be inhibited to block growth of these cancers. We describe CCT3833, a new drug that inhibits both RAF and SRC, which may be effective in KRAS-mutant cancers.

RESULTS

We show that CCT3833 inhibits RAF and SRC in KRAS-mutant tumors in vitro and in vivo, and that it inhibits tumor growth at well-tolerated doses in mice. CCT3833 has been evaluated in a phase I clinical trial (NCT02437227) and we report here that it significantly prolongs progression-free survival of a patient with a G12VKRAS spindle cell sarcoma who did not respond to a multikinase inhibitor and therefore had limited treatment options.

CONCLUSIONS

New drug CCT3833 elicits significant preclinical therapeutic efficacy in KRAS-mutant colorectal, lung and pancreatic tumor xenografts, demonstrating a treatment option for several areas of unmet clinical need. Based on these preclinical data and the phase I clinical unconfirmed response in a patient with KRAS-mutant spindle cell sarcoma, CCT3833 requires further evaluation in patients with other KRAS-mutant cancers.

Preclinical Evidence That Trametinib Enhances the Response to Antiangiogenic Tyrosine Kinase Inhibitors in Renal Cell Carcinoma

Sunitinib and pazopanib are antiangiogenic tyrosine kinase inhibitors (TKI) used to treat metastatic renal cell carcinoma (RCC). However, the ability of these drugs to extend progression-free and overall survival in this patient population is limited by drug resistance. It is possible that treatment outcomes in RCC patients could be improved by rationally combining TKIs with other agents. Here, we address whether inhibition of the Ras-Raf-MEK-ERK1/2 pathway is a rational means to improve the response to TKIs in RCC. Using a xenograft model of RCC, we found that tumors that are resistant to sunitinib have a significantly increased angiogenic response compared with tumors that are sensitive to sunitinib in vivo. We also observed significantly increased levels of phosphorylated ERK1/2 in the vasculature of resistant tumors, when compared with sensitive tumors. These data suggested that the Ras-Raf-MEK-ERK1/2 pathway, an important driver of angiogenesis in endothelial cells, remains active in the vasculature of TKI-resistant tumors. Using an in vitro angiogenesis assay, we identified that the MEK inhibitor (MEKI) trametinib has potent antiangiogenic activity. We then show that, when trametinib is combined with a TKI in vivo, more effective suppression of tumor growth and tumor angiogenesis is achieved than when either drug is utilized alone. In conclusion, we provide preclinical evidence that combining a TKI, such as sunitinib or pazopanib, with a MEKI, such as trametinib, is a rational and efficacious treatment regimen for RCC.

Paradox-breaking RAF inhibitors that also target SRC are effective in drug-resistant BRAF mutant melanoma

BRAF and MEK inhibitors are effective in BRAF mutant melanoma, but most patients eventually relapse with acquired resistance, and others present intrinsic resistance to these drugs. Resistance is often mediated by pathway reactivation through receptor tyrosine kinase (RTK)/SRC-family kinase (SFK) signaling or mutant NRAS, which drive paradoxical reactivation of the pathway. We describe pan-RAF inhibitors (CCT196969, CCT241161) that also inhibit SFKs. These compounds do not drive paradoxical pathway activation and inhibit MEK/ERK in BRAF and NRAS mutant melanoma. They inhibit melanoma cells and patient-derived xenografts that are resistant to BRAF and BRAF/MEK inhibitors. Thus, paradox-breaking pan-RAF inhibitors that also inhibit SFKs could provide first-line treatment for BRAF and NRAS mutant melanomas and second-line treatment for patients who develop resistance.

Abstract 3704: Novel panRAF inhibitors active in melanomas that are resistant to BRAF-selective, or BRAF-selective/MEK inhibitor combinations

The protein kinase BRAF is mutated ∼40% of human melanomas. BRAF is a component of the RAS/RAF/MEK/ERK pathway and BRAF or MEK inhibitors increase progression-free and overall survival in melanoma patients with BRAF mutations. However, most patients relapse with acquired resistance and ∼20% of patients present intrinsic resistance and do not respond to these drugs. We describe here two novel compounds that target mutant BRAF and wild-type CRAF. Our compounds inhibited the growth of melanoma cells that were resistant to BRAF-selective inhibitors. ERK pathway reactivation is responsible for resistance to BRAF targeted therapies in ∼60% of the patients and in ∼25% of patients resistance is driven by acquisition of mutations in NRAS. We show that our compounds inhibited the growth of melanoma cells that were resistant to BRAF-selective inhibitors due to pathway reactivation mediated by different mechanisms. We show that the drugs were active against patient derived xenografts (PDXs) from patients with acquired or intrinsic resistance to BRAF-selective inhibitors and in whose tumors resistance was associated with ERK pathway reactivation. Further, our compounds are active in a PDX from a patient whose tumor developed acquired resistance to a combination of a BRAF-selective plus a MEK inhibitor and associated with acquisition of an NRAS mutation. Thus, our panRAF inhibitors can inhibit melanomas with different mechanisms of acquired or intrinsic resistance to BRAF-selective and BRAF-selective/MEK inhibitor combinations, potentially providing first-line treatment for naïve patients and second-line treatments for a range of relapsed patients.

Citation Format: Maria R. Girotti, Filipa Lopes, Natasha Preece, Dan Niculescu-Duvaz, Alfonso Zambon, Lawrence Davies, Steven Whittaker, Grazia Saturno, Amaya Viros, Malin Pedersen, Bart MJM Suijkerbuijk, Delphine Menard, Robert Mcleary, Louise Johnson, Laura Fish, Sarah Ejiama, Berta Sanchez-Laorden, Neil Carragher, Kenneth Macleod, Garry Ashton, Anna Marusiak, Alberto Fusi, John Brognard, Margaret Frame, Paul Lorigan, Caroline J. Springer, Richard Marais. Novel panRAF inhibitors active in melanomas that are resistant to BRAF-selective, or BRAF-selective/MEK inhibitor combinations. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3704. doi:10.1158/1538-7445.AM2014-3704

RAS mutations in cutaneous squamous-cell carcinomas in patients treated with BRAF inhibitors

BACKGROUND

Cutaneous squamous-cell carcinomas and keratoacanthomas are common findings in patients treated with BRAF inhibitors.

METHODS

We performed a molecular analysis to identify oncogenic mutations (HRAS, KRAS, NRAS, CDKN2A, and TP53) in the lesions from patients treated with the BRAF inhibitor vemurafenib. An analysis of an independent validation set and functional studies with BRAF inhibitors in the presence of the prevalent RAS mutation was also performed.

RESULTS

Among 21 tumor samples, 13 had RAS mutations (12 in HRAS). In a validation set of 14 samples, 8 had RAS mutations (4 in HRAS). Thus, 60% (21 of 35) of the specimens harbored RAS mutations, the most prevalent being HRAS Q61L. Increased proliferation of HRAS Q61L-mutant cell lines exposed to vemurafenib was associated with mitogen-activated protein kinase (MAPK)-pathway signaling and activation of ERK-mediated transcription. In a mouse model of HRAS Q61L-mediated skin carcinogenesis, the vemurafenib analogue PLX4720 was not an initiator or a promoter of carcinogenesis but accelerated growth of the lesions harboring HRAS mutations, and this growth was blocked by concomitant treatment with a MEK inhibitor.

CONCLUSIONS

Mutations in RAS, particularly HRAS, are frequent in cutaneous squamous-cell carcinomas and keratoacanthomas that develop in patients treated with vemurafenib. The molecular mechanism is consistent with the paradoxical activation of MAPK signaling and leads to accelerated growth of these lesions. (Funded by Hoffmann-La Roche and others; ClinicalTrials.gov numbers, NCT00405587, NCT00949702, NCT01001299, and NCT01006980.).

Novel hinge binder improves activity and pharmacokinetic properties of BRAF inhibitors

Mutated BRAF serine/threonine kinase is implicated in several types of cancer, with particularly high frequency in melanoma and colorectal carcinoma. We recently reported on the development of BRAF inhibitors based on a tripartite A-B-C system featuring an imidazo[4,5]pyridin-2-one group hinge binder. Here we present the design, synthesis, and optimization of a new series of inhibitors with a different A-B-C system that has been modified by the introduction of a range of novel hinge binders (A ring). The optimization of the hinge binding moiety has enabled the development of compounds with low nanomolar potencies in both BRAF inhibition and cellular assays. These compounds display optimal pharmacokinetic properties that warrant further in vivo investigations.

A novel, selective, and efficacious nanomolar pyridopyrazinone inhibitor of V600EBRAF

Oncogenic BRAF is a critical driver of proliferation and survival and is thus a validated therapeutic target in cancer. We have developed a potent inhibitor, termed 1t (CCT239065), of the mutant protein kinase, (V600E)BRAF. 1t inhibits signaling downstream of (V600E)BRAF in cancer cells, blocking DNA synthesis, and inhibiting proliferation. Importantly, we show that 1t is considerably more selective for mutated BRAF cancer cell lines compared with wild-type BRAF lines. The inhibitor is well tolerated in mice and exhibits excellent oral bioavailability (F = 71%). Suppression of (V600E)BRAF-mediated signaling in human tumor xenografts was observed following oral administration of a single dose of 1t. As expected, the growth rate in vivo of a wild-type BRAF human tumor xenograft model is unaffected by inhibitor 1t. In contrast, 1t elicits significant therapeutic responses in mutant BRAF-driven human melanoma xenografts.

Gradient analysis of the distribution of mammals in Stage III of Kakadu National Park, with a review of the distribution patterns of mammals across north-western Australia

A total of 56 native mammal species (about one quarter of the species of land mammals known from Australia) was recorded from the Stage III area of Kakadu National Park, Northern Territory. A single environmental gradient (of substrate and disturbance) described well the distributions of species other than bats from this area. For most species, there was little shift in gradient position between three trapping periods (spaced over three years). The mammal fauna comprised a rocky upland assemblage, a lowland monsoon rainforest-swamp assemblage, and an open forest-woodland assemblage. Mammal diversity and abundance was greatest in the rocky uplands. The distribution of most bat species was not clearly associated with this gradient. The Stage III mammal fauna is compared with that described from elsewhere in north-western Australia. Across this region, the fauna shows little variation with longitude, but undergoes substantial latitudinal change in conjunction with a steep rainfall gradient. The habitat reSationships of the Stage III mammal fauna are broadly repeated across north-western Australia. The fauna of sandstone ranges is attenuated with decreasing size and increasing isolation of these ranges. The mammal fauna of monsoon rainforests is depauperate, reflecting the small size and patchiness of this habitat. The mammal fauna of open forest/woodland is characterised by extensive distributions of its constituent species and a relative lack of arboreal folivores and small macropods.

Effect of vitamin A on rat hepatic mixed-function oxidases, glutathione transferase activity and generations of oxygen radicals

Rat hepatic microsomal mixed-function oxidase activities were not significantly affected by vitamin A deficiency. Similarly cytosolic glutathione S-transferase and glutathione reductase activities as well as total glutathione levels were unaffected by the vitamin A status. Induction of the mixed-function oxidases by 3-methylcholanthrene or phenobarbitone was independent of the vitamin A status. No significant differences in microsomal chemiluminescence, before and following challenge with tertiary butyl hydroperoxide, were evident between the vitamin-A-deficient animals and those maintained on vitamin-A-supplemented diets. The present findings indicate that the protective action of vitamin A against chemical carcinogens is unlikely to involve modulation of the enzyme systems responsible for their metabolism.