Thiophanate-methyl induces notochord toxicity by activating the PI3K-mTOR pathway in zebrafish (Danio rerio) embryos

Thiophanate-methyl (TM), a typical pesticide widely used worldwide, was detected in rivers, soil, fruits, and vegetables. Thus, it is urgent to identify the potential harm of TM residual to non-target organisms and its molecular mechanisms. We used zebrafish (Danio rerio) in this study to evaluate TM toxicity. TM exposure induced developmental toxicity, including inhibited hatchability, reduced heart rates, restrained spontaneous locomotion, and decreased body length. Furthermore, we observed obvious toxicity in the notochord and detected increased expression levels of notochord-related genes (shha, col2a, and tbxta) by in situ hybridization in zebrafish larvae. In addition, calcein staining, alkaline phosphatase (ALP) activity analysis, and anatomic analysis indicated that TM induced notochord toxicity. We used rescue experiments to verify whether the PI3K-mTOR pathway involved in the notochord development was the cause of notochord abnormalities. Rapamycin and LY294002 (an inhibitor of PI3K) relieve notochord toxicity caused by TM, including morphological abnormalities. In summary, TM might induce notochord toxicity by activating the PI3K-mTOR pathway in zebrafish.

Recent Developments in Targeting RAS Downstream Effectors for RAS-Driven Cancer Therapy

Aberrant activity of oncogenic rat sarcoma virus (RAS) protein promotes tumor growth and progression. RAS-driven cancers comprise more than 30% of all human cancers and are refractory to frontline treatment strategies. Since direct targeting of RAS has proven challenging, efforts have been centered on the exploration of inhibitors for RAS downstream effector kinases. Two major RAS downstream signaling pathways, including the Raf/MEK/Erk cascade and the phosphatidylinositol-3-kinase (PI3K) pathway, have become compelling targets for RAS-driven cancer therapy. However, the main drawback in the blockade of a single RAS effector is the multiple levels of crosstalk and compensatory mechanisms between these two pathways that contribute to drug resistance against monotherapies. A growing body of evidence reveals that the sequential or synergistic inhibition of multiple RAS effectors is a more convenient route for the efficacy of cancer therapy. Herein, we revisit the recent developments and discuss the most promising modalities targeting canonical RAS downstream effectors for the treatment of RAS-driven cancers.

Targeting RTK-PI3K-mTOR Axis in Gliomas: An Update

Gliomas are the most common and challenging malignancies of the central nervous system (CNS), due to their infiltrative nature, tendency to recurrence, and poor response to treatments. Indeed, despite the advances in neurosurgical techniques and in radiation therapy, the modest effects of therapy are still challenging. Moreover, tumor recurrence is associated with the onset of therapy resistance; it is therefore critical to identify effective and well-tolerated pharmacological approaches capable of inducing durable responses in the appropriate patient groups. Molecular alterations of the RTK/PI3K/Akt/mTOR signaling pathway are typical hallmarks of glioma, and several clinical trials targeting one or more players of this axis have been launched, showing disappointing results so far, due to the scarce BBB permeability of certain compounds or to the occurrence of resistance/tolerance mechanisms. However, as RTK/PI3K/mTOR is one of the pivotal pathways regulating cell growth and survival in cancer biology, targeting still remains a strong rationale for developing strategies against gliomas. Future rigorous clinical studies, aimed at addressing the tumor heterogeneity, the interaction with the microenvironment, as well as diverse posology adjustments, are needed-which might unravel the therapeutic efficacy and response prediction of an RTK/PI3K/mTOR-based approach.

Co-Targeting PIM Kinase and PI3K/mTOR in NSCLC

Simple Summary

PIM kinases interact with major oncogenic players, including the PI3K/Akt pathway, and provide an escape mechanism leading to drug resistance. This study examined PIM kinase expression in NSCLC and the potential of PIM1 as a prognostic marker. The effect on cell signaling of novel preclinical PI3K/mTOR/PIM kinase inhibitor IBL-301 was compared to PI3K/mTOR inhibition in vitro and ex vivo. PI3K-mTOR inhibitor sensitive (H1975P) and resistant (H1975GR) cells were compared for altered IL6/STAT3 pathway expression and sensitivity to IBL-301. All three PIM kinases are expressed in NSCLC and PIM1 is a marker of poor prognosis. IBL-301 inhibited c-Myc, the PI3K-Akt and JAK/STAT pathways in vitro and in NSCLC tumor tissue explants. IBL-301 also inhibited secreted pro-inflammatory cytokine MCP-1. PIM kinases were activated in H1975GR cells which were more sensitive to IBL-301 than H1975P cells. A miRNA signature of PI3K-mTOR resistance was validated. Co-targeting PIM kinase and PI3K-mTOR warrants further clinical investigation.

Abstract

PIM kinases are constitutively active proto-oncogenic serine/threonine kinases that play a role in cell cycle progression, metabolism, inflammation and drug resistance. PIM kinases interact with and stabilize p53, c-Myc and parallel signaling pathway PI3K/Akt. This study evaluated PIM kinase expression in NSCLC and in response to PI3K/mTOR inhibition. It investigated a novel preclinical PI3K/mTOR/PIM inhibitor (IBL-301) in vitro and in patient-derived NSCLC tumor tissues. Western blot analysis confirmed PIM1, PIM2 and PIM3 are expressed in NSCLC cell lines and PIM1 is a marker of poor prognosis in patients with NSCLC. IBL-301 decreased PIM1, c-Myc, pBAD and p4EBP1 (Thr37/46) and peIF4B (S406) protein levels in-vitro and MAP kinase, PI3K-Akt and JAK/STAT pathways in tumor tissue explants. IBL-301 significantly decreased secreted pro-inflammatory cytokine MCP-1. Altered mRNA expression, including activated PIM kinase and c-Myc, was identified in Apitolisib resistant cells (H1975GR) by an IL-6/STAT3 pathway array and validated by Western blot. H1975GR cells were more sensitive to IBL-301 than parent cells. A miRNA array identified a dysregulated miRNA signature of PI3K/mTOR drug resistance consisting of regulators of PIM kinase and c-Myc (miR17-5p, miR19b-3p, miR20a-5p, miR15b-5p, miR203a, miR-206). Our data provides a rationale for co-targeting PIM kinase and PI3K-mTOR to improve therapeutic response in NSCLC.

Acylglycerol Kinase Maintains Metabolic State and Immune Responses of CD8+ T Cells

CD8⁺ T cell expansions and functions rely on glycolysis, but the mechanisms underlying CD8⁺ T cell glycolytic metabolism remain elusive. Here, we show that acylglycerol kinase (AGK) is required for the establishment and maintenance of CD8⁺ T cell metabolic and functional fitness. AGK deficiency dampens CD8⁺ T cell antitumor functions in vivo and perturbs CD8⁺ T cell proliferation in vitro. Activation of phosphatidylinositol-3-OH kinase (PI3K)-mammalian target of rapamycin (mTOR) signaling, which mediates elevated CD8⁺ T cell glycolysis, is tightly dependent on AGK kinase activity. Mechanistically, T cell antigen receptor (TCR)- and CD28-stimulated recruitment of PTEN to the plasma membrane facilitates AGK-PTEN interaction and AGK-triggered PTEN phosphorylation, thereby restricting PTEN phosphatase activity in CD8⁺ T cells. Collectively, these results demonstrate that AGK maintains CD8⁺ T cell metabolic and functional state by restraining PTEN activity and highlight a critical role for AGK in CD8⁺ T cell metabolic programming and effector function.

Behavioral neuroscience of autism

Autism spectrum disorder (ASD) is a neurodevelopmental disorder. Several genetic causes of ASD have been identified and this has enabled researchers to construct mouse models. Mouse behavioral tests reveal impaired social interaction and communication, as well as increased repetitive behavior and behavioral inflexibility in these mice, which correspond to core behavioral deficits observed in individuals with ASD. However, the connection between these behavioral abnormalities and the underlying dysregulation in neuronal circuits and synaptic function is poorly understood. Moreover, different components of the ASD phenotype may be linked to dysfunction in different brain regions, making it even more challenging to chart the pathophysiological mechanisms involved in ASD. Here we summarize the research on mouse models of ASD and their contribution to understanding pathophysiological mechanisms. Specifically, we emphasize abnormal serotonin production and regulation, as well as the disruption in circadian rhythms and sleep that are observed in a subset of ASD, and propose that spatiotemporal disturbances in brainstem development may be a primary cause of ASD that propagates towards the cerebral cortex.