LukS-PV Induces Apoptosis via the SET8-H4K20me1-PIK3CB Axis in Human Acute Myeloid Leukemia Cells

SET8 inhibition preserves PTEN to attenuate kidney cell apoptosis in cisplatin nephrotoxicity

The aberrant expression of SET8, a histone methyltransferase that mediates H4 lysine 20 mono-methylation (H4K20me1), is implicated in the pathogenesis of various tumors, however, its role in acute kidney injury (AKI) is unknown. Here we showed that SET8 and H4K20me1 were upregulated in the murine kidney with AKI induced by cisplatin, along with increased renal tubular cell injury and apoptosis and decreased expression of E-cadherin and Phosphatase and Tensin Homolog (PTEN). Suppression of SET8 by UNC0379 improved renal function, attenuated tubule damage, and restored expression of PTEN, but not E-cadherin. UNC0379 was also effective in lessening cisplatin-induced DNA damage response (DDR) as indicated by reduced expression of γ-H2AX, p53, p21, and alleviating cisplatin-impaired autophagy as shown by retained expression of Atg5, Beclin-1, and CHMP2A and enhanced levels of LC3-II in the kidney. Consistently, inhibition of SET8 with either UNC0379 or siRNA mitigated apoptosis and DDR, and restored autophagy, along with PTEN preservation in cultured renal proximal tubular epithelial cell (TKPTs) exposed to cisplatin. Further studies showed that inhibition of PTEN with Bpv or siRNA potentiated cisplatin-induced apoptosis, DDR, and hindered autophagy, and conversely, alleviated by overexpression of PTEN in TKPTs. Finally, blocking PTEN largely abolished the inhibitory effect of UNC0379 on apoptosis. Taken together, these results suggest that SET8 inhibition protects against cisplatin-induced AKI and renal cell apoptosis through a mechanism associated with the preservation of PTEN, which in turn inhibits DDR and restores autophagy.

Anticancer efficacy of biosynthesized silver nanoparticles loaded with recombinant truncated parasporin-2 protein

Bacterial toxins have received a great deal of attention in the development of cancer treatments. Parasporin-2 (PS2Aa1 or Mpp46Aa1) is a Bacillus thuringiensis parasporal protein that preferentially destroys human cancer cells while not harming normal cells, making it a promising anticancer treatment. With the efficient development and sustainable silver nanoparticles (AgNPs) synthesis technology, the biomedical use of AgNPs has expanded. This study presents the development of a novel nanotoxin composed of biosynthesized silver nanoparticles loaded with the N-terminal truncated PS2Aa1 toxin. MOEAgNPs were synthesized using a biological method, with Moringa oleifera leaf extract and maltose serving as reducing and capping agents. The phytochemicals present in M. oleifera leaf extract were identified by GC-MS analysis. MOEAgNPs were loaded with N-terminal truncated PS2Aa1 fused with maltose-binding protein (MBP-tPS2) to formulate PS2-MOEAgNPs. The PS2-MOEAgNPs were evaluated for size, stability, toxin loading efficacy, and cytotoxicity. PS2-MOEAgNPs demonstrated dose-dependent cytotoxicity against the T-cell leukemia MOLT-4 and Jurkat cell lines but had little effect on the Hs68 fibroblast or normal cell line. Altogether, the current study provides robust evidence that PS2-MOEAgNPs can efficiently inhibit the proliferation of T-cell leukemia cells, thereby suggesting their potential as an alternative to traditional anticancer treatments.

Mechanism of SET8 Activates the Nrf2-KEAP1-ARE Signaling Pathway to Promote the Recovery of Motor Function after Spinal Cord Injury

Background

Spinal cord injury (SCI) is a common injury of the central nervous system (CNS), and astrocytes are relatively abundant glial cells in the CNS that impairs the recovery of motor function after SCI. It was confirmed that the oxidative stress of mitochondria leads to the accumulation of reactive oxygen species (ROS) in cells, which plays a key role in the motor function of astrocytes. However, the mechanism by which oxidative stress affects astrocyte motility after SCI is still unexplained. Therefore, this study investigated the influence of SET8-regulated oxidative stress on astrocyte autophagy levels after SCI in rats and the potential mechanisms of action.

Methods

We used real-time quantitative PCR, western blotting, and immunohistochemical staining to analyze SET8, Keap1, and Nrf2 expression at the cellular level and in SCI tissues. ChIP to detect H4K20me1 enrichment in the Keap1 promoter region under OE-SET8 (overexpression of SET8) conditions. Western blotting was used to assess the expression of signature proteins of astrocytes, proteins associated with autophagy, proteins associated with glial scar formation, reactive oxygen species (ROS) levels in cells using DHE staining, and astrocyte number, morphological alterations, and induction of glial scar formation processes using immunofluorescence. In addition, the survival rate of neurons after SCI in rats was examined by using NiSSl staining.

Results

OE-SET8 upregulates the enrichment of H4K20me1 in Keap1, inhibits Keap1 expression, activates the Nrf2-ARE signaling pathway to suppress ROS accumulation, inhibits oxidative stress-induced autophagy and glial scar formation in astrocytes, and leads to reduced neuronal loss, which promoted the recovery and improvement of motor function after SCI in rats.

Conclusion

Overexpression of SET8 alleviated oxidative stress by regulating Keap1/Nrf2/ARE, inhibited astrocyte autophagy levels, and reduced glial scar formation as well as neuronal loss, thereby promoting improved recovery of motor function after SCI. Thus, the SET8/H4K20me1 regulatory function may be a promising cellular therapeutic intervention point after SCI.

LukS-PV inhibits the proliferation of hepatocellular carcinoma cells by maintaining FOXO3 stability via the PI3K/AKT signaling pathway

Hepatocellular carcinoma(HCC) is one of the common malignant tumors. LukS-PV is the S component of Panton-Valetine leukocidin(PVL) secreted by Staphylococcus aureus. Forkhead box O3 (FOXO3) is a member of the FOXO subfamily of transcription factors that acts as a tumor suppressor. In this study, we investigated the role of LukS-PV on the proliferation of HCC and explored possible mechanisms. We treated HCC cells with various concentrations of LukS-PV and evaluated the effect of LukS-PV on cell viability using the cell counting kit-8 and colony formation assays. Real-time PCR and western blot assays were used to analyze mRNA and protein expression levels, respectively. Immunofluorescence staining was performed to examine the intracellular localization of FOXO3. The expression of FOXO3 and its downstream target genes were analyzed by immunohistochemical staining. The protein synthesis inhibitor cycloheximide and the proteosome inhibitor MG132 were used to explore the potential mechanisms by which LukS-PV regulated FOXO3. We demonstrated that LukS-PV inhibited the proliferation of HCC cells in a concentration dependent manner. LukS-PV upregulated FOXO3 expression both in vitro and in vivo. Moreover, LukS-PV facilitated the entry of FOXO3 into the nucleus and, subsequently, regulated the transcription of downstream target genes. In addition, we discovered that LukS-PV decreased the expression of phosphorylated FOXO3 through the PI3K/AKT signaling pathway and maintained FOXO3 protein stability via the ubiquitin-proteasome pathway. Taken together, our data indicated that LukS-PV exert anticancer activities through FOXO3. LukS-PV may be a promising candidate for HCC treatment.