SIRT1/APE1 promotes the viability of gastric cancer cells by inhibiting p53 to suppress ferroptosis

Potential role of SIRT1 in cell ferroptosis

Ferroptosis is a novel form of cell death that uniquely requires iron and is characterized by iron accumulation, the generation of free radicals leading to oxidative stress, and the formation of lipid peroxides, which distinguish it from other forms of cell death. The regulation of ferroptosis is extremely complex and is closely associated with a spectrum of diseases. Sirtuin 1 (SIRT1), a NAD + -dependent histone deacetylase, has emerged as a pivotal epigenetic regulator with the potential to regulate ferroptosis through a wide array of genes intricately associated with lipid metabolism, iron homeostasis, glutathione biosynthesis, and redox homeostasis. This review provides a comprehensive overview of the specific mechanisms by which SIRT1 regulates ferroptosis and explores its potential therapeutic value in the context of multiple disease pathologies, highlighting the significance of SIRT1-mediated ferroptosis in treatment strategies.

Implication of protein post translational modifications in gastric cancer

Gastric cancer (GC) is one of the most common and highly lethal malignant tumors worldwide, and its occurrence and development are regulated by multiple molecular mechanisms. Post-translational modifications (PTM) common forms include ubiquitylation, phosphorylation, acetylation and methylation. Emerging research has highlighted lactylation and glycosylation. The diverse realm of PTM and PTM crosstalk is linked to many critical signaling events involved in neoplastic transformation, carcinogenesis and metastasis. This review provides a comprehensive overview of the impact of PTM on the occurrence and progression of GC. Specifically, aberrant PTM have been shown to alter the proliferation, migration, and invasion capabilities of GC cells. Moreover, PTM are closely associated with resistance to chemotherapeutic agents in GC. Notably, this review also discusses the phenomenon of PTM crosstalk, highlighting the interactions among PTM and their roles in regulating signaling pathways and protein functions. Therefore, in-depth investigation into the mechanisms of PTM and the development of targeted therapeutic strategies hold promise for advancing early diagnosis, treatment, and prognostic evaluation of GC, offering novel insights and future research directions.

SIRT1 promotes doxorubicin-induced breast cancer drug resistance and tumor angiogenesis via regulating GSH-mediated redox homeostasis

Sirtuin 1 (SIRT1), a member of histone deacetylase III family, plays a pivotal role in mediating chemoresistance in several cancers, including breast cancer. However, the molecular mechanism by which the deregulated SIRT1 promotes doxorubicin (Dox) resistance is still elusive. Here, we showed that the cell proliferation rates and invasive properties of MDA-MB-231 breast cancer cells were increased from low- to high-Dox-resistant cells. In agreement, severe combined immunodeficiency disease (SCID) mice bearing labeled MDA-MB-231high Dox-Res cells showed significantly higher tumor growth, angiogenesis, and metastatic ability than parental MDA-MB-231 cells. Interestingly, the levels of SIRT1 and glutathione (GSH) were positively correlated with the degree of Dox-resistance. Dox-induced SIRT1 promoted NRF2 nuclear translocation with an accompanying increase in the antioxidant response element promotor activity and GSH levels. In contrast, inhibition of SIRT1 by EX527 greatly reversed these events. More so, Dox-resistance-induced pro-proliferative, proangiogenic, and invasive effects were obviated with depletion of either SIRT1 or GSH. Together, Dox-induced SIRT1 promotes dysregulation of redox homeostasis leading to breast cancer chemoresistance, tumor aggressiveness, angiogenesis, and metastasis.

Ferroptosis: opening up potential targets for gastric cancer treatment

The fifth most frequent cancer in the world is gastric cancer. It ranks as the fourth most common reason for cancer-related deaths. Even though surgery is the only curative treatment for stomach cancer, adding adjuvant radiotherapy and chemotherapy is preferable than only surgery. The majority of patients, however, are discovered to be extremely tardy the first time and have a terrible prognosis. Therefore, it is necessary to create more viable therapy modalities. A growing number of studies in recent years have shown that ferroptosis and many cancer types are related. This gives our treatment a fresh viewpoint. We investigated the relationship between different signal pathways and non-coding RNA on ferroptosis in gastric cancer cells. Also discussed the targets cause ferroptosis resistance increased or reduced to the influence of the chemoresistance,proliferation and metastasis.

SIRT1 silencing ameliorates malignancy of non-small cell lung cancer via activating FOXO1

Non-small cell lung cancer (NSCLC), being the most prevalent and lethal malignancy affecting the lungs, poses a significant threat to human health. This research aims at illustrating the precise role and related mechanisms of silent information regulator type-1 (SIRT1) in NSCLC progression. The expression pattern of SIRT1 in NSCLC cell lines was examined using quantitative real-time polymerase chain reaction and western blotting. Functional assays in NSCLC cell lines validated the biological capabilities of SIRT1 on malignant phenotypes, and its impact on tumorigenicity was further evaluated in vivo. In addition, the FOXO1 inhibitor AS1842856 was applied to verify the role of SIRT1 on FOXO pathway in vitro. SIRT1 expression was prominently elevated in NSCLC cell lines. The depletion of SIRT1 retarded the capabilities of proliferation, migration and invasion, while enhancing apoptosis in NSCLC cells. Furthermore, SIRT1 silencing restricted the tumorigenesis of NSCLC in vivo. Additionally, AS1842856 treatment ameliorated the inhibitory effect of SIRT1 deficiency on malignant phenotypes in NSCLC cells. SIRT1 deletion exerted an anti-oncogenic role in NSCLC via activation of FOXO1.

APE1 inhibition enhances ferroptotic cell death and contributes to hepatocellular carcinoma therapy

Ferroptosis, a regulated form of cell death triggered by iron-dependent lipid peroxidation, has emerged as a promising therapeutic strategy for cancer treatment, particularly in hepatocellular carcinoma (HCC). However, the mechanisms underlying the regulation of ferroptosis in HCC remain to be unclear. In this study, we have identified a novel regulatory pathway of ferroptosis involving the inhibition of Apurinic/apyrimidinic endonuclease 1 (APE1), a key enzyme with dual functions in DNA repair and redox regulation. Our findings demonstrate that inhibition of APE1 leads to the accumulation of lipid peroxidation and enhances ferroptosis in HCC. At the molecular level, the inhibition of APE1 enhances ferroptosis which relies on the redox activity of APE1 through the regulation of the NRF2/SLC7A11/GPX4 axis. We have identified that both genetic and chemical inhibition of APE1 increases AKT oxidation, resulting in an impairment of AKT phosphorylation and activation, which leads to the dephosphorylation and activation of GSK3β, facilitating the subsequent ubiquitin-proteasome-dependent degradation of NRF2. Consequently, the downregulation of NRF2 suppresses SLC7A11 and GPX4 expression, triggering ferroptosis in HCC cells and providing a potential therapeutic approach for ferroptosis-based therapy in HCC. Overall, our study uncovers a novel role and mechanism of APE1 in the regulation of ferroptosis and highlights the potential of targeting APE1 as a promising therapeutic strategy for HCC and other cancers.

Sirt6-Mediated Cell Death Associated with Sirt1 Suppression in Gastric Cancer

BACKGROUND

Gastric cancer, one of the leading causes of cancer-related death, is strongly associated with H. pylori infection, although other risk factors have been identified. The sirtuin (Sirt) family is involved in the tumorigenesis of gastric cancer, and sirtuins can have pro- or anti-tumorigenic effects.

METHODS

After determining the overall survival rate of gastric cancer patients with or without Sirt6 expression, the effect of Sirt6 upregulation was also tested using a xenograft mouse model. The regulation of Sirt6 and Sirt1, leading to the induction of mouse double minute 2 homolog (MDM2) and reactive oxygen species (ROS), was mainly analyzed using Western blotting and immunofluorescence staining, and gastric cancer cell (SNU-638) death associated with these proteins was measured using flow cytometric analysis.

RESULTS

Sirt6 overexpression led to Sirt1 suppression in gastric cancer cells, resulting in a higher level of gastric cancer cell death in vitro and a reduced tumor volume. ROS and MDM2 expression levels were upregulated by Sirt6 overexpression and/or Sirt1 suppression according to Western blot analysis. The upregulated ROS ultimately led to gastric cancer cell death as determined via Western blot and flow cytometric analysis.

CONCLUSION

We found that the upregulation of Sirt6 suppressed Sirt1, and Sirt6- and Sirt1-induced gastric cancer cell death was mediated by ROS production. These findings highlight the potential of Sirt6 and Sirt1 as therapeutic targets for treating gastric cancer.

An all-in-one enzymatic DNA network based on catalytic hairpin assembly for label-free and highly sensitive detection of APE1

Apurinic/apyrimidinic endonuclease 1 (APE1), identified as a prospective cancer biomarker, plays a vital role in the occurrence and progression of cancer cell lines and impacts on genome stability. However, conventional approaches typically rely on the interactions between the antigen and antibody, limiting their utility for qualitative assessments of APE1 expression. Herein, an all-in-one enzymatic DNA network (EDN) assay with catalytic hairpin assembly for label-free and ultrasensitive detection of APE1 has been developed. In this work, the blocking strand can inhibit the initiator by obstructing the complementary region, preventing the hairpin from hybridizing in the absence of APE1 targets. While the presence of targets can activate the unlocking of the initiator, which can trigger the catalytic hairpin reaction, and increase the fluorescent signal. Under optimal conditions, the developed sensing method can detect the target APE1 down to 4.78 × 10-6 U mL-1 with a wide linear range from 5 × 10-6 U mL-1 to 30 U mL-1. This strategy has also been successfully applied to the analysis of complicated biological samples compared to ELISA, demonstrating its potential applications in biochemical and molecular biology research as well as clinical diagnostics. Overall, benefiting from the high amplification efficiency, this strategy has successfully and simply detected low-abundance APE1 without additional enzyme isolation steps, presenting great potential for clinical detection applications.