Signal Transduction and Targeted Therapy最新文献

Aberrant RNA alternative splicing in cancer generates varied novel isoforms and protein variants that facilitate cancer progression. Here, we employed the advanced long-read full-length transcriptome sequencing on gallbladder normal tissues, tumors, and cell lines to establish a comprehensive full-length gallbladder transcriptomic atlas. It is of note that receptor tyrosine kinases were one of the most dynamic components with highly variable transcript, with Erb-B2 receptor tyrosine kinase 2 (ERBB2) as a prime representative. A novel transcript, designated ERBB2 i14e, was identified for encoding a novel functional protein, and its protein expression was elevated in gallbladder cancer and strongly associated with worse prognosis. With the regulation of splicing factors ESRP1/2, ERBB2 i14e was alternatively spliced from intron 14 and the encoded i14e peptide was proved to facilitate the interaction with ERBB3 and downstream signaling activation of AKT. ERBB2 i14e was inducible and its expression attenuated anti-ERBB2 treatment efficacy in tumor xenografts. Further studies with patient derived xenografts models validated that ERBB2 i14e blockage with antisense oligonucleotide enhanced the tumor sensitivity to trastuzumab and its drug conjugates. Overall, this study provides a gallbladder specific long-read transcriptome profile and discovers a novel mechanism of trastuzumab resistance, thus ultimately devising strategies to improve trastuzumab therapy.

The pancreas, an organ with dual functions, regulates blood glucose levels through the endocrine system by secreting hormones such as insulin and glucagon. It also aids digestion through the exocrine system by secreting digestive enzymes. Complex interactions and signaling mechanisms between the endocrine and exocrine functions of the pancreas play a crucial role in maintaining metabolic homeostasis and overall health. Compelling evidence indicates direct and indirect crosstalk between the endocrine and exocrine parts, influencing the development of diseases affecting both. From a developmental perspective, the exocrine and endocrine parts share the same origin-the "tip-trunk" domain. In certain circumstances, pancreatic exocrine cells may transdifferentiate into endocrine-like cells, such as insulin-secreting cells. Additionally, several pancreatic diseases, including pancreatic cancer, pancreatitis, and diabetes, exhibit potential relevance to both endocrine and exocrine functions. Endocrine cells may communicate with exocrine cells directly through cytokines or indirectly by regulating the immune microenvironment. This crosstalk affects the onset and progression of these diseases. This review summarizes the history and milestones of findings related to the exocrine and endocrine pancreas, their embryonic development, phenotypic transformations, signaling roles in health and disease, the endocrine-exocrine crosstalk from the perspective of diseases, and potential therapeutic targets. Elucidating the regulatory mechanisms of pancreatic endocrine and exocrine signaling and provide novel insights for the understanding and treatment of diseases.

Cas12h1 is a compact CRISPR-associated nuclease from functionally diverse type V CRISPR-Cas effectors and recognizes a purine-rich protospacer adjacent motif (PAM) distinct from that of other type V Cas effectors. Here, we report the nickase preference of Cas12h1, which predominantly cleaves the nontarget strand (NTS) of a double-stranded DNA (dsDNA) substrate. In addition, Cas12h1 acts as a nickase in human cells. We further determined the cryo-EM structures of Cas12h1 in the surveillance, R-loop formation, and interference states, revealing the molecular mechanisms involved in the crRNA maturation, target recognition, R-loop formation, nuclease activation and target degradation. Cas12h1 notably recognizes a broad 5’-DHR-3’ PAM (D is A, G, or T; H is A, C, or T; R is A or G) both in vitro and in human cells. In addition, Cas12h1 utilizes a distinct activation mechanism that the lid motif undergoes a “flexible to stable” transition to expose the catalytic site to the substrate. A high-fidelity nucleic acid detector, Cas12h1^hf, was developed through rational engineering, which distinguishes single-base mismatches and retains comparable on-target activities. Our results shed light on the molecular mechanisms underlying Cas12h1 nickase, improve the understanding of type V Cas effectors, and expand the CRISPR toolbox for genome editing and molecular diagnosis.

Accumulated evidence has implicated the diverse and substantial influence of lactate on cellular differentiation and fate regulation in physiological and pathological settings, particularly in intricate conditions such as cancer. Specifically, lactate has been demonstrated to be pivotal in molding the tumor microenvironment (TME) through its effects on different cell populations. Within tumor cells, lactate impacts cell signaling pathways, augments the lactate shuttle process, boosts resistance to oxidative stress, and contributes to lactylation. In various cellular populations, the interplay between lactate and immune cells governs processes such as cell differentiation, immune response, immune surveillance, and treatment effectiveness. Furthermore, communication between lactate and stromal/endothelial cells supports basal membrane (BM) remodeling, epithelial-mesenchymal transitions (EMT), metabolic reprogramming, angiogenesis, and drug resistance. Focusing on lactate production and transport, specifically through lactate dehydrogenase (LDH) and monocarboxylate transporters (MCT), has shown promise in the treatment of cancer. Inhibitors targeting LDH and MCT act as both tumor suppressors and enhancers of immunotherapy, leading to a synergistic therapeutic effect when combined with immunotherapy. The review underscores the importance of lactate in tumor progression and provides valuable perspectives on potential therapeutic approaches that target the vulnerability of lactate metabolism, highlighting the Heel of Achilles for cancer treatment.

AXL, a member of the TAM receptor family, has emerged as a potential target for advanced-stage human malignancies. It is frequently overexpressed in different cancers and plays a significant role in various tumor-promoting pathways, including cancer cell proliferation, invasion, metastasis, epithelial–mesenchymal transition (EMT), angiogenesis, stemness, DNA damage response, acquired therapeutic resistance, immunosuppression, and inflammatory responses. Beyond oncology, AXL also facilitates viral infections, including SARS-CoV-2 and Zika highlighting its importance in both cancer and virology. In preclinical models, small-molecule kinase inhibitors targeting AXL have shown promising anti-tumorigenic potential. This review primarily focuses on the induction, regulation and biological functions of AXL in mediating these tumor-promoting pathways. We discuss a range of therapeutic strategies, including recently developed small-molecule tyrosine kinase inhibitors (TKIs), monoclonal antibodies, and antibody–drug conjugates (ADCs), anti-AXL-CAR, and combination therapies. These interventions are being examined in both preclinical and clinical studies, offering the potential for improved drug sensitivity and therapeutic efficacy. We further discuss the mechanisms of acquired therapeutic resistance, particularly the crosstalk between AXL and other critical receptor tyrosine kinases (RTKs) such as c-MET, EGFR, HER2/HER3, VEGFR, PDGFR, and FLT3. Finally, we highlight key research areas that require further exploration to enhance AXL-mediated therapeutic approaches for improved clinical outcomes.

Fulminant myocarditis (FM) is a severe inflammatory condition of the myocardium that often results in sudden death, particularly in young individuals. In this study, we employed single-nucleus and spatial transcriptomics to perform a comprehensive analysis of coxsackievirus B3 (CVB3)-induced FM in A/J mice, spanning seven distinct time points pre- and post-treatment. Our findings reveal that mesothelial cells play a critical role in the early stage of myocarditis by acting as primary targets for CVB3 infection. This triggers the activation of macrophages, initiating a cascade of inflammation. Subsequently, pro-inflammatory Inflammatory_Mac and T cells infiltrate the myocardium, driving tissue damage. We also identified Cd8⁺ effector T cells as key mediators of cardiomyocyte injury. These cells release cytotoxic molecules, particularly IFN-γ, which modulates the expression of Spi1, a factor implicated in exacerbating cardiomyocyte death and amplifying disease progression. Therapeutic interventions targeting the IFN-γ/Spi1 axis demonstrated significant efficacy in FM models. Notably, intravenous immunoglobulin (IVIG) treatment reduced mortality, suppressed viral proliferation, and mitigated the hyperinflammatory state of FM. IVIG therapy also downregulated IFN-γ and Spi1 expression, underscoring its immunomodulatory and therapeutic potential. This comprehensive spatiotemporal transcriptomic analysis provides profound insights into the pathogenesis of FM and highlights actionable therapeutic targets, paving the way for more effective management strategies for this life-threatening condition.

The importance of MCL-1 in leukemogenesis has prompted development of MCL-1 antagonists e.g., S63845, MIK665. However, their effectiveness in acute myeloid leukemia (AML) is limited by compensatory MCL-1 accumulation via the ubiquitin proteasome system. Here, we investigated mechanisms by which kinase inhibitors with Src inhibitory activity e.g., bosutinib (SKI-606) might circumvent this phenomenon. MCL-1 antagonist/SKI-606 co-administration synergistically induced apoptosis in diverse AML cell lines. Consistently, Src or MCL-1 knockdown with shRNA markedly sensitized cells to MCL-1 inhibitors or SKI-606 respectively, while ectopic MCL-1 expression significantly diminished apoptosis. Mechanistically, MCL-1 antagonist exposure induced MCL-1 up-regulation, an event blocked by Src inhibitors or Src shRNA knock-down. MCL-1 down-regulation was associated with diminished transcription and increased K48-linked degradative ubiquitination. Enhanced cell death depended functionally upon down-regulation of phosphorylated STAT3 (Tyr705/Ser727) and cytoprotective downstream targets c-Myc and BCL-xL, as well as BAX/BAK activation, and NOXA induction. Importantly, the Src/MCL-1 inhibitor regimen robustly killed primary AML cells, including primitive progenitors, but spared normal hematopoietic CD34⁺ cells and human cardiomyocytes. Notably, the regimen significantly improved survival in an MV4-11 cell xenograft model, while reducing tumor burden in two patient-derived xenograft (PDX) AML models and increased survival in a third. These findings argue that Src inhibitors such as SKI-606 potentiate MCL-1 antagonist anti-leukemic activity in vitro and in vivo by blocking MCL-1 antagonist-mediated cytoprotective MCL-1 accumulation by promoting degradative ubiquitination, disrupting STAT-3-mediated transcription, and inducing NOXA-mediated MCL-1 degradation. They also suggest that this strategy may improve MCL-1 antagonist efficacy in AML and potentially other malignancies.