Downregulation of Rad51 expression and activity potentiates the cytotoxic effect of osimertinib in human non-small cell lung cancer cells.

INTRODUCTION: Osimertinib (AZD9291) is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that has shown significant clinical benefits in patients with EGFR-sensitizing mutations or the EGFR T790M mutation. The homologous recombination (HR) pathway is crucial for repairing DNA double-strand breaks (DSBs). Rad51 plays a central role in HR, facilitating the search for homology and promoting DNA strand exchange between homologous DNA molecules. Rad51 is overexpressed in numerous types of cancer cells. B02, a specific small molecule inhibitor of Rad51, inhibits the DNA strand exchange activity of Rad51. Previous studies have indicated that B02 disrupted Rad51 foci formation in response to DNA damage and inhibited DSBs repair in human cells and sensitized them to chemotherapeutic drugs in vitro and in vivo. However, the potential therapeutic effects of combining osimertinib with a Rad51 inhibitor are not well understood. The aim of this study is to elucidate whether the downregulation of Rad51 expression and activity can enhance the osimertinib-induced cytotoxicity in non-small cell lung cancer (NSCLC) cells. METHODS: We used the MTS, trypan blue dye exclusion and colony-formation ability assay to determine whether osimertinib alone or in combination with B02 had cytotoxic effects on NSCLC cell lines. Real-time PCR was conducted to measure the amounts of Rad51 mRNA. The protein levels of phosphorylated AKT and Rad51 were determined by Western blot analysis. RESULTS: We found that osimertinib reduced Rad51 expression by inactivating AKT activity. Rad51 knockdown using siRNA or AKT inactivation through the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 or si-AKT RNA transfection enhanced the cytotoxic and growth inhibitory effects of osimertinib. In contrast, AKT-CA (a constitutively active form of AKT) vector-enforced expression could mitigate the cytotoxic and cell growth inhibitory effects of osimertinib. Furthermore, B02 significantly enhanced the cytotoxic and cell growth inhibitory effects of osimertinib in NSCLC cells. Compared to parental cells, the activation of AKT and Rad51 expression in osimertinib-resistant cells could not be significantly inhibited by osimertinib treatment. Moreover, the increased expression of Rad51 is associated with the resistance mechanism in osimertinib-resistant H1975 and A549 cells. CONCLUSION: Collectively, the downregulation of Rad51 expression and activity enhances the cytotoxic effect of osimertinib in human NSCLC cells.

Calycosin inhibited MIF-mediated inflammatory chemotaxis of macrophages to ameliorate ischemia reperfusion-induced acute kidney injury.

BACKGROUND: Inflammatory macrophage infiltration plays a critical role in acute kidney disease induced by ischemia-reperfusion (IRI-AKI). Calycosin is a natural flavone with multiple bioactivities. This study aimed to investigate the therapeutic role of calycosin in IRI-AKI and its underlying mechanism. METHODS: The renoprotective and anti-inflammatory effects of calycosin were analyzed in C57BL/6 mice with IRI-AKI and lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. RNA-seq was used for mechanism investigation. The molecular target of calycosin was screened by in silico methods and validated by surface plasmon resonance (SPR). Macrophage chemotaxis was analyzed using Transwell and agarose gel spot assays. RESULTS: Calycosin treatment significantly reduced serum creatinine and urea nitrogen and attenuated tubular destruction in IRI-AKI mice. Additionally, calycosin markedly suppressed NF-κB signaling activation and the expression of inflammatory mediators IL-1ß and TNF-α in IRI-AKI kidneys and LPS-stimulated RAW 264.7 cells. Interestingly, RNA-seq revealed calycosin remarkably downregulated chemotaxis-related pathways in RAW 264.7 cells. Among the differentially expressed genes, Ccl2/MCP-1, a critical chemokine mediating macrophage inflammatory chemotaxis, was downregulated in both LPS-stimulated RAW 264.7 cells and IRI-AKI kidneys. Consistently, calycosin treatment attenuated macrophage infiltration in the IRI-AKI kidneys. Importantly, in silico target prediction, molecular docking, and SPR assay demonstrated that calycosin directly binds to macrophage migration inhibitory factor (MIF). Functionally, calycosin abrogated MIF-stimulated NF-κB signaling activation and Ccl2 expression and MIF-mediated chemotaxis in RAW 264.7 cells. CONCLUSIONS: In summary, calycosin attenuates IRI-AKI by inhibiting MIF-mediated macrophage inflammatory chemotaxis, suggesting it could be a promising therapeutic agent for the treatment of IRI-AKI.

Clinical characteristics and molecular mechanisms underlying bladder cancer in individuals with spinal cord injury: a systematic review.

BACKGROUND: Patients with spinal cord injury have a relatively high risk for bladder cancer and often complicated with bladder cancer in advanced stages, and the degree of aggressiveness of malignancy is high. Most of the literature is based on disease clinical features while, our study reviews the clinical characteristics and molecular mechanisms of spinal cord injury patients with bladder cancer, so that it might help clinicians better recognize and manage these patients. METHOD: We searched PubMed, Web of Science and Embase, using retrieval type like ("Neurogenic Lower Urinary Tract Dysfunction" OR "Spinal cord injury" OR "Spinal Cord Trauma") AND ("bladder cancer" OR "bladder neoplasm" OR "bladder carcinoma" OR "Urinary Bladder Neoplasms" OR "Bladder Tumor"). In Web of Science, the retrieval type was searched as "Topic", and in PubMed and Embase, as "All Field". The methodological quality of eligible studies and their risk of bias were assessed using the Newcastle-Ottawa scale. This article is registered in PROSPERO with the CBD number: CRD42024508514. RESULT: In WOS, we searched 219 related papers, in PubMed, 122 and in Embase, 363. Thus, a total of 254 articles were included after passing the screening, within a time range between 1960 and 2023. A comprehensive analysis of the data showed that the mortality and incidence rates of bladder cancer in spinal cord injury patients were higher than that of the general population, and the most frequent pathological type was squamous cell carcinoma. In parallel to long-term urinary tract infection and indwelling catheterization, the role of molecules such as NO, MiR 1949 and Rb 1. was found to be crucial pathogenetically. CONCLUSION: This review highlights the risk of bladder cancer in SCI patients, comprehensively addressing the clinical characteristics and related molecular mechanisms. However, given that there are few studies on the molecular mechanisms of bladder cancer in spinal cord injury, further research is needed to expand the understanding of the disease.

LncRNA SNHG26 promotes gastric cancer progression and metastasis by inducing c-Myc protein translation and an energy metabolism positive feedback loop.

Metastasis is a bottleneck in cancer treatment. Studies have shown the pivotal roles of long noncoding RNAs (lncRNAs) in regulating cancer metastasis; however, our understanding of lncRNAs in gastric cancer (GC) remains limited. RNA-seq was performed on metastasis-inclined GC tissues to uncover metastasis-associated lncRNAs, revealing upregulated small nucleolar RNA host gene 26 (SNHG26) expression, which predicted poor GC patient prognosis. Functional experiments revealed that SNHG26 promoted cellular epithelial-mesenchymal transition and proliferation in vitro and in vivo. Mechanistically, SNHG26 was found to interact with nucleolin (NCL), thereby modulating c-Myc expression by increasing its translation, and in turn promoting energy metabolism via hexokinase 2 (HK2), which facilitates GC malignancy. The increase in energy metabolism supplies sufficient energy to promote c-Myc translation and expression, forming a positive feedback loop. In addition, metabolic and translation inhibitors can block this loop, thus inhibiting cell proliferation and mobility, indicating potential therapeutic prospects in GC.