No abstract

No abstract

Aggregated mining development has direct and indirect impacts on vegetation changes. This impact shows spatial differences due to the complex influence of multiple mines, which is a common issue in resource regions. To estimate the spatial heterogeneity of vegetation response to mining activities, we coupled vegetation changes and mining development through a geographically weighted regression (GWR) model for three cumulative periods between 1999 and 2018 in integrated resource regions of northwestern China. Vegetation changes were monitored by Sen’s slope and the Mann–Kendall test according to a total of 72 Landsat images. Spatial distribution of mining development was quantified, due to four land-use maps in 2000, 2005, 2010, and 2017. The results showed that 80% of vegetation in the study area experienced different degrees of degradation, more serious in the overlapping areas of multiple mines and mining areas. The scope of influence for single mines on vegetation shrunk by about 48%, and the mean coefficients increased by 20%, closer to mining areas. The scope of influence for multiple mines on vegetation gradually expanded to 86% from the outer edge to the inner overlapping areas of mining areas, where the mean coefficients increased by 92%. The correlation between elevation and vegetation changes varied according to the average elevation of the total mining areas. Ultimately, the available ecological remediation should be systematically considered for local conditions and mining consequences.

The KRASG12C mutation is found in 11% of non-small cell lung cancers, 4% of colorectal cancers, and 2% of pancreatic cancers in the U.S., and drives these cancers by shifting the cellular equilibrium of KRAS towards the GTP-bound, active state, KRASG12C(ON). The resulting increased levels of KRASG12C(ON) in turn increase signaling output to initiate and support the oncogenic state. In recent years, a class of KRASG12C(OFF) inhibitors has transformed the treatment landscape for patients with cancers bearing KRASG12C. These inhibitors work via sequestration of the GDP-bound, inactive state, KRASG12C(OFF), starving cancer cells of their oncogenic driver, KRASG12C(ON). Recent reports on the nature of resistance to KRASG12C(OFF) inhibitors suggest this class of drugs can be overcome through reactivation of KRASG12C to the ON form. Direct inhibition of KRASG12C(ON) with a first in class, potent, orally bioavailable, selective, tri-complex inhibitor RMC-6291, represents a more robust approach and presents the possibility that RMC-6291 will be a ‘best-in-class’ inhibitor of tumors harboring KRASG12C. RMC-6291 is a potent covalent inhibitor of KRASG12C(ON) that forms a tri-complex within tumor cells between KRASG12C(ON) and cyclophilin A (CypA), a highly abundant immunophilin. The assembled tri-complex prevents KRASG12C(ON) from signaling via steric blockade of RAS effector binding. In cells, kinetic analyses demonstrate near-immediate disruption of RAS effector binding and extinction of KRASG12C(ON) signaling. Oral administration of RMC-6291 produces deep and durable suppression of RAS pathway activity in KRASG12C tumor models and drives profound tumor regressions in vivo at well-tolerated doses. In a mouse clinical trial consisting of multiple patient- and cell line-derived xenograft models of KRASG12C NSCLC, RMC-6291 outperformed adagrasib, a KRASG12C(OFF) inhibitor, by increasing the number of responses, the depth of tumor regressions, and the durability of responses. Combination treatment with RMC-6291 and SHP2 or SOS1 inhibitors was well tolerated in preclinical models and further increased anti-tumor activity, likely by preventing reactivation of wild-type RAS proteins that cooperate with KRASG12C to fuel cancer growth. RMC-6291 also combined well with immune checkpoint inhibitors, sensitizing KRASG12C-bearing cancer models to anti-tumor immunity. RMC-6291 is a next-generation, mutant-selective inhibitor of KRASG12C(ON) that overcomes limitations of first-generation KRASG12C(OFF) inhibitors in preclinical models by directly targeting the active form of this important oncogenic driver. Citation Format: Robert J. Nichols, Y.C. Yang, Jim Cregg, Chris J. Schulze, Zhican Wang, Richa Dua, Jingjing Jiang, Lindsay S. Garrenton, Nicole Nasholm, Alun Bermingham, John E. Knox, Kyle Seamon, Michael Longhi, Kang-Jye Chou, Shaoling Li, David P. Wildes, Mallika Singh, Elena S. Koltun, Adrian L. Gill, Jacqueline A.M. Smith. RMC-6291, a next-generation tri-complex KRASG12C(ON) inhibitor, outperforms KRASG12C(OFF) inhibitors in preclinical models of KRASG12C cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3595.

Aims: Isoliquiritigenin (ISL), a flavonoid from Glycyrrhiza glabra, has previously been reported to have anti-tumor effects in vivo and in vitro. However, the mechanisms whereby ISL exerts its anticancer effects remain poorly understood in hepatocellular carcinoma (HCC). Purpose: In the present study, we investigated the anticancer efficacy and associated mechanisms of ISL in HCC MHCC97-H and SMMC7721 cells. Results: We found that ISL inhibited cell viability and proliferation and induced apoptosis in a dose-and time-dependent manner in liver cancer lines. Furthermore, ISL could activate autophagy in HCC cells, and the autophagy inhibitor HCQ enhances ISL-induced apoptosis in HCC cells. Additionally, ISL induced apoptosis and autophagy through inhibition of the PI3K/Akt/mTOR pathway. Most importantly, in a xenograft tumor model in nude mice, data showed that the administration of ISL decreased tumor growth and concurrently promoted the expression of LC3-II and cleaved-caspase-3. Interestingly, we found that ISL inhibits mTOR by docking onto the ATP-binding pocket of mTOR (ie, it competes with ATP). We thus suggest that mTOR is a potential target for ISL inhibition of hepatocellular carcinoma development, which could be of interest for future investigations. Conclusion: Taken together, the results reveal that ISL effectively inhibited proliferation and induced apoptosis in HCC through autophagy induction in vivo and in vitro, probably via the PI3K/Akt/mTOR pathway. ISL may be a potential therapeutic agent for hepatocellular carcinoma.

No abstract

The KRASG12C mutation is found in 11% of non-small cell lung cancers and 4% of colorectal cancers. Recently, a class of KRASG12C(OFF) inhibitors has shown promising activity in patients whose cancers bear KRASG12C. These data validate KRASG12C as an oncogenic driver, as well the mechanism of action of the KRASG12C(OFF) inhibitor class – sequestration of inactive, GDP-bound KRASG12C(OFF) proteins. Previous work has demonstrated this mechanism of action is vulnerable to adaptive tumor cell responses that activate KRASG12C by increasing upstream signaling and driving the cellular pool of KRASG12C towards the RAS(ON) state. These escape mechanisms, in which KRASG12C can be reactivated in the presence of a KRASG12C(OFF) inhibitor, highlight the potential for an inhibitor that directly targets and disables the KRASG12C(ON) form. Using structure-based drug design, we have discovered RM-032, a potent covalent inhibitor of KRASG12C(ON) that forms a tri-complex between KRASG12C(ON) and cyclophilin A (CypA), a highly abundant immunophilin. The assembled tri-complex prevents KRASG12C(ON) from signaling via steric blockade of RAS effector binding. In cells, kinetic analyses demonstrate near-immediate disruption of RAS effector binding and extinction of KRASG12C(ON) signaling. RM-032 is dual selective for KRASG12C(ON) and NRASG12C(ON). In vitro, RM-032 drives increased durability of inhibition of both RAS pathway signaling and cell proliferation in KRASG12C tumor cells compared with KRASG12C(OFF) inhibition. RM-032 displays attractive drug-like properties including cross-species oral bioavailability, and is predicted to achieve adequate exposures following oral dosing in humans. Oral administration of RM-032 produces deep and durable suppression of RAS pathway activity in KRASG12C tumor models and drives profound tumor regressions in vivo at well-tolerated doses. Across multiple tumor xenograft models, advanced KRASG12C(ON) inhibitors, including RM-032, appear to outperform KRASG12C(OFF) inhibitors. RM-032 permits a broad array of combination opportunities for treating KRASG12C mutant cancer types where single agent KRASG12C(ON) inhibition may be insufficient, for example with agents targeting nodes both upstream (e.g., SHP2 and SOS1) and downstream (e.g., MEK and ERK) of RAS, as well as parallel pathways (e.g., mTORC1). RM-032 is a next generation mutant-selective inhibitor of KRASG12C(ON) that may overcome liabilities of first-generation KRASG12C(OFF) inhibitors and provide additional benefit to patients by directly targeting the active form of this important oncogenic driver mutation. Citation Format: Robert J. Nichols, Jim Cregg, Christopher J. Schulze, Zhican Wang, Kevin Yang, Jingjing Jiang, Daniel M. Whalen, Rich Hansen, Lindsay S. Garrenton, Alun Bermingham, John E. Knox, Tiffany Choy, Denise Reyes, Mayra Rios, Kyle Seamon, Michael Longhi, Kang-Jye Chou, Shaoling Li, David P. Wildes, Mallika Singh, Elena S. Koltun, Adrian L. Gill, Jacqueline A. M. Smith. A next generation tri-complex KRASG12C(ON) inhibitor directly targets the active, GTP-bound state of mutant RAS and may overcome resistance to KRASG12C(OFF) inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1261.

Background The diversity of histologic composition reflects the inter- and intra-tumor heterogeneity of lung adenocarcinomas (LUADs) macroscopically. Insights into the oncological characteristics and tumor microenvironment (TME) of different histologic subtypes of LUAD at the single-cell level can help identify potential therapeutic vulnerabilities and combinational approaches to improve the survival of LUAD patients. Methods Through comparative profiling of cell communities defined by scRNA-seq data, we characterized the TME of LUAD samples of distinct histologic subtypes, with relevant results further confirmed in multiple bulk transcriptomic, proteomic datasets and an independent immunohistochemical validation cohort. Results We find that the hypoxic and acidic situation is the worst in the TME of solid LUADs compared to other histologic subtypes. Besides, the tumor metabolic preferences vary across histologic subtypes and may correspondingly impinge on the metabolism and function of immune cells. Remarkably, tumor cells from solid LUADs upregulate energy and substance metabolic activities, particularly the folate-mediated one-carbon metabolism and the key gene MTHFD2, which could serve as a potential therapeutic target. Additionally, ubiquitination modifications may also be involved in the progression of histologic patterns. Immunologically, solid LUADs are characterized by a predominance of exhausted T cells and immunosuppressive myeloid cells, where the hypoxic, acidified and nutrient-deprived TME has a non-negligible impact. Discrepancies in stromal cell function, evidenced by varying degrees of stromal remodeling and fibrosis, may also contribute to the specific immune phenotype of solid LUADs. Conclusions Overall, our research proposes several potential entry points to improve the immunosuppressive TME of solid LUADs, thereby synergistically potentiating their immunotherapeutic efficacy, and may provide precise therapeutic strategies for LUAD patients of distinct histologic subtype constitution.