Recombinant adeno-associated virus serotype 9 with p65 ribozyme protects H9c2 cells from oxidative stress through inhibiting NF-κB signaling pathway

Recombinant Adeno-associated Virus 9-mediated Expression of Kallistatin Suppresses Lung Tumor Growth in Mice

BACKGROUND

Lung cancer remains the most common cause of cancer-related deaths in China and worldwide. Traditional surgery and chemotherapy do not offer an effective cure, although gene therapy may be a promising future alternative. Kallistatin (Kal) is an endogenous inhibitor of angiogenesis and tumorigenesis. Recombinant adeno-associated virus (rAAV) is considered the most promising vector for gene therapy of many diseases due to persistent and long-term transgenic expression.

OBJECTIVE

The aim of this study was to investigate whether rAAV9-Kal inhibited NCI-H446 subcutaneous xenograft tumor growth in mice.

METHODS

The subcutaneous xenograft mode was induced by subcutaneous injection of 2×10⁷ H446 cells into the dorsal skin of BALB/c nude mice. The mice were administered with ssrAAV9-Kal (single- stranded rAAV9) or dsrAAV9-Kal (double-stranded rAAV9) by intraperitoneal injection (I.P.). Tumor microvessel density (MVD) was examined by anti-CD34 staining to evaluate tumor angiogenesis.

RESULTS

Compared with the PBS (blank control) group, tumor growth in the high-dose ssrAAV9-Kal group was inhibited by 40% by day 49, and the MVD of tumor tissues was significantly decreased.

CONCLUSION

The results indicate that this therapeutic strategy is a promising approach for clinical cancer therapy and implicate rAAV9-Kal as a candidate for gene therapy of lung cancer.

Overexpression of IκBα in cardiomyocytes alleviates hydrogen peroxide-induced apoptosis and autophagy by inhibiting NF-κB activation

Background

Inflammation and oxidative stress play predominant roles in the initiation and progression of ischaemia/reperfusion (I/R) injury, with nuclear factor kappa B (NF-κB) serving as a crucial mediator. Overexpression of the inhibitor of κB alpha (IκBα) gene is hypothesized to have protective effects against apoptosis and autophagy in cardiomyocytes subjected to hydrogen peroxide (H₂O₂) by inhibiting the NF-κB pathway.

Methods

The IκBα^{S32A, S36A} gene was transfected via adeno-associated virus serotype 9 (AAV9) delivery into neonatal rat ventricular cardiomyocytes (NRVMs) prior to H₂O₂ treatment. NRVMs were divided into control, H₂O₂, GFP + H₂O₂, IκBα+H₂O₂, and pyrrolidine dithiocarbamate (PDTC) + H₂O₂ groups. Nuclear translocation of the NF-κB p65 subunit was evaluated by immunofluorescence and Western blotting. Cell viability was assessed by Cell Counting Kit-8 assay. Supernatant lactate dehydrogenase (LDH) and intracellular malondialdehyde (MDA) were measured to identify H₂O₂-stimulated cytotoxicity. Apoptosis was determined by Annexin V-PE/7-AAD staining, and the mitochondrial membrane potential (ΔΨm) was detected by JC-1 staining. Western blotting was used to detect apoptosis- and autophagy-related proteins.

Results

IκBα transfection significantly increased cell viability and ΔΨm but decreased the supernatant LDH and cellular MDA levels in cardiomyocytes exposed to H₂O₂. Meanwhile, IκBα overexpression decreased H₂O₂-induced apoptosis by upregulating the Bcl-2/Bax ratio and reduced autophagy by downregulating the expression of Beclin-1 and the LC3-II/LC3-I ratio. These effects partly accounted for the ability of IκBα to inhibit the NF-κB signalling pathway, as evidenced by decreases in p65 phosphorylation and nuclear translocation. Indeed, the effects of inactivation of NF-κB signalling with the specific inhibitor PDTC resembled the cardioprotective effects of IκBα during H₂O₂ stimulation.

Conclusion

IκBα overexpression can ameliorate H₂O₂-induced apoptosis, autophagy, oxidative injury, and ΔΨm loss through inhibition of the NF-κB signalling pathway. These findings suggest that IκBα transfection can result in successful resistance to oxidative stress-induced damage by inhibiting NF-κB activation, which may provide a potential therapeutic target for the prevention of myocardial I/R injury.