Journal of cellular biochemistry最新文献

The expression of claudins (CLDNs), major components of tight junctions (TJs), is abnormal in various solid tumors. CLDN14 is highly expressed in human colorectal cancer (CRC) tissues and confers chemoresistance. CLDN14 may become a novel therapeutic target for CRC, but CLDN14-targeting drugs have not been developed. Here, we searched for a CLDN14-targeting peptide, which can suppress CLDN14 expression and chemoresistance using human CRC-derived DLD-1 and LoVo cells. Among some short peptides which mimic the second extracellular loop structure of CLDN14, PSGMK most strongly suppressed the protein expression of CLDN14. The mRNA expression of other endogenous TJ components was unchanged by PSGMK. The PSGMK-induced reduction of CLDN14 protein was inhibited by chloroquine, a lysosome inhibitor, and monodansylcadaverine, a clathrin-dependent endocytosis inhibitor, indicating that PSGMK may enhance endocytosis and lysosomal degradation of CLDN14. In a three-dimensional culture model, the oxidative stress was significantly reduced by PSGMK, whereas hypoxia stress was not. Furthermore, the expression levels of nuclear factor erythroid 2-related factor 2, an oxidative stress response factor, and its target genes were decreased by PSGMK. These results suggest that PSGMK relieves stress conditions in spheroids. The cell viability of spheroids was decreased by anticancer drugs such as doxorubicin and oxaliplatin, which was exaggerated by the cotreatment with PSGMK. Our data indicate that CLDN14-targeting peptide, PSGMK has an anti-chemoresistance effect in CRC cells.

Multidrug-resistant (MDR) cancer cells maintain redox homeostasis to eliminate oxidative stress-mediated cell death. This study explores the effects of solasodine on regulating P-glycoprotein (P-gp) expression through the Nrf2/Keap1 signaling pathway and oxidative stress-induced sensitization of drug-resistant cancer cells to chemotherapeutics. Initially, the oxidative stress indicators such as intracellular ROS generation, the levels of 8-hydroxy-2-deoxyguanosine (8-OHdG) and gamma-H2AX (γ-H2AX) in the KBChR-8-5 drug-resistant cells were measured. Additionally, the protein expression levels of Nuclear factor erythroid 2-related factor 2 (Nrf-2), Kelch-like ECH-associated protein 1 (Keap1), and ATP Binding Cassette Subfamily B Member 1 (ABCB1)/P-gp were measured at various concentrations of solasodine (1, 5, & 10 µM) through immunofluorescence and western blot analysis. The antioxidant activities in the KBChR-8-5 cells were assessed using established protocols. In this investigation, the treatment with solasodine and doxorubicin combination showed a notable increase in intracellular ROS generation in KBChR-8-5 cells. Furthermore, this combination treatment led to enhanced nuclear condensation, elevated levels of 8-OHdG, and increased γ-H2AX foci formation in the KBChR-8-5 cells. Solasodine treatment effectively inhibited the nuclear translocation of Nrf2 and activation of the ABCB1 gene, consequently preventing overexpression of P-gp in KBChR-8-5 cells. Additionally, the combination therapy increased the lipid peroxidation levels while simultaneously reducing the activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and the levels of glutathione (GSH). These results demonstrated that solasodine disrupts redox balance, and overcomes drug resistance by downregulating P-gp via regulating Nrf2/Keap1 signaling pathway in MDR cancer cells.

Streptococcus pneumonia is a Gram-positive and facultative anaerobic bacterium that causes a number of diseases, including otitis media, community-acquired pneumonia, sepsis, and meningitis. With the emergence of antibiotic-resistant strains, there is an urgent need to develop antibiotics with a novel mechanism. The toxin-antitoxin (TA) system, which is primarily found in prokaryotes, consists of a toxin and its equivalent antitoxin genes. The YefM-YoeB module is a Type II TA system, where the YoeB toxin functions as a putative mRNA interferase upon activation, while the YefM antitoxin acts as a transcription repressor by binding to its promoter region along with YoeB. In this study, we determined the crystal structure of the YefM-YoeB complex from S. pneumoniae TIGR4 to comprehend the binding mechanism of the TA system. Furthermore, an in vitro ribonuclease activity assay was conducted to identify the ribonuclease activity of the YoeB toxin. Additionally, furthermore, the oligomeric state of the YefM-YoeB complex in solution was investigated, and a DNA-binding mode was proposed. These structural and functional insights into the YefM-YoeB complex could provide valuable information for the development of novel antibiotics targeting S. pneumonia-associated diseases.

Retraction: Y. Peng, X. Ai, and B. Peng, "Trans-cleaving Hammerhead Ribozyme in Specific Regions Can Improve Knockdown Efficiency In Vivo," Journal of Cellular Biochemistry (Early View): https://doi.org/10.1002/jcb.30249. The above article, published online on 11 April 2022 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors; the journal Editor-in-Chief, Christian Behl; and Wiley Periodicals LLC. The retraction has been agreed upon the authors' request due to concerns related to the data presented in the article. The authors admitted significant errors in the evaluation of the fluorescence intensity, resulting in inaccurate data on the trans-cleaving efficiency of the presented system. They also informed the journal of errors in the results of the immunoblot assays. As the identified errors affect the overall conclusions of the study, the article is retracted.

Phytotherapy has rendered a new insight towards the treatment of various cancers, including oral cancer with fewer side effects, over the traditional chemotherapeutic drugs to overcome chemoresistance. Shikonin (Shk) is a natural biologically active alkaloid found in the Lithospermum erythrorhizon plant's root. It has potent cytotoxic activities against various cancers. Our study revealed the release time and anticancer potential of Shk on the SCC9 and H357 oral cancer cell lines. We investigated the antiproliferative, antimigratory, cell cycle arresting and apoptosis promoting activity of Shk in oral cancer cells by performing MTT and morphological assay, colony, and tumor sphere formation assay, AO/EtBr and DAPI staining, Annexin V-FITC/PI staining, assay for reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) measurement, comet assay, qRT-PCR, and western blot analysis. We also checked the interaction of DNA and Shk by docking and CD spectroscopy and EtBr displacement assay. As a result, we found that Shk reduced the viability, proliferation, and tumorigenicity of SCC9 and H357 cells in a time and concentration-dependent manner. We obtained half-maximal inhibitory concentration (IC₅₀) at 0.5 µM for SCC9 and 1.25 µM for H357. It promotes apoptosis via overexpressing proapoptotic Bax and caspase 3 via enhancing ROS that leads to MMP depletion and DNA damage and arrests cells at the G2/M & G2/S phase. The antimigratory activity of Shk was performed by analyzing the expression of markers of epithelial-mesenchymal transition like E-cadherin, ZO-1, N-cadherin, and vimentin. These overall results recommended that Shk shows potent anticancer activity against oral cancer cell lines in both in vitro and ex vivo conditions. So, it could be an excellent agent for the treatment of oral cancer.

Chrysosplenetin (CHR), an O-methylated flavonol from Chamomilla recutita and Laggera pterodonta, has previously demonstrated efficacy in enhancing osteoblast differentiation for treating postmenopausal osteoporosis. This study aims to evaluate CHR's potential to inhibit osteoclastogenesis and prevent bone deterioration in both in vitro and in vivo models. Using tartaric acid-resistant acid phosphatase staining and hydroxyapatite resorption assays, we examined the impact of CHR on RANKL-induced osteoclasts derived from mouse bone marrow monocytes. Additionally, Western blot analysis and qRT-PCR were utilized to assess the protein and gene expressions within the MAPK and NF-κB signaling pathways, as well as the NFATc1 pathway. In vivo, CHR's effects were validated using micro-CT and histomorphometry in an ovariectomized mouse model, showing significant reduction in osteoclast activity and bone loss. The study confirms CHR's inhibition of osteoclastogenesis through interference with RANKL-mediated signaling pathways, suggesting its potential as a novel therapeutic agent for osteolytic conditions related to osteoclast-osteoblast dysregulation.

Cell-based therapies represent a major advancement in the treatment and management of HIV/AIDS, with a goal to overcome the limitations of traditional antiretroviral therapy (ART). These innovative approaches not only promise a functional cure by reconstructing the immune landscape but also address the persistent viral reservoirs. For example, stem cell therapies have emerged from the foundational success of allogeneic hematopoietic stem cell transplantation in curing HIV infection in a limited number of cases. B cell therapies make use of genetically modified B cells constitutively expressing broadly neutralizing antibodies (bNAbs) against target viral particles and infected cells. Adoptive cell transfer (ACT), including TCR-T therapy, CAR-T cells, NK-CAR cells, and DC-based therapy, is adapted from cancer immunotherapy and repurposed for HIV eradication. In this review, we summarize the mechanisms through which these engineered cells recognize and destroy HIV-infected cells, the modification strategies, and their role in sustaining remission in the absence of ART. The review also addresses the challenges to cell-based therapies against HIV and discusses the recent advancements aimed at overcoming them.

Genomic imprinting is essential for mammalian development. PGC7, an important maternal factor, binds to dimethylated histone H3K9 (H3K9me2), maintaining DNA methylation in zygotes and stem cells. However, the underlying molecular mechanisms of PGC7-maintained genomic imprinting in stem cells are not clear. Our previous study has identified that PGC7 interacts with HP1BP3, a novel member of the histone H1 family. In this study, we found that PGC7 interacts with the central globular domain of HP1BP3 through its C-terminal tail and that HP1BP3 is responsible for the recruitment of PGC7 at the Meg3 differentially methylated region (DMR) in the Dlk1-Dio3 imprinted domain. HP1BP3 or PGC7 depletion decreases enrichment in the Meg3-DMR, leading to DNA hypermethylation in this region. Moreover, the cooperative binding of PGC7 and HP1BP3 can antagonize the enrichment of DNMT3A in the Meg3-DMR, and the depletion of HP1BP3 or PGC7 separately induces chromosome decondensation in this region. In summary, this is the first study demonstrating that PGC7 and HP1BP3 synergistically maintain the methylation status of the Meg3-DMR by enabling a chromatin configuration that interferes with the binding of the de novo DNA methyltransferase DNMT3A.

The most common and aggressive brain cancer, glioblastoma, is characterized by hypoxia and poor survival. The pro-tumour transcription factor, hypoxia-inducible factor (HIF), is regulated via HIF-hydroxylases that require ascorbate as cofactor. Decreased HIF-hydroxylase activity triggers the hypoxic pathway driving cancer progression. Tissue ascorbate accumulates via the sodium-dependent vitamin C transporter-2 (SVCT2). We hypothesize that glioblastoma cells rely on SVCT2 for ascorbate accumulation, and that knockout of this transporter would disrupt the regulation of the hypoxic pathway by ascorbate. Ascorbate uptake was measured in glioblastoma cell lines (U87MG, U251MG, T98G) by high-performance liquid chromatography. CRISPR/Cas9 was used to knockout SVCT2. Cells were treated with cobalt chloride, desferrioxamine or 5% oxygen, with/without ascorbate, and key hypoxic pathway proteins were measured using Western blot analysis. Ascorbate uptake was cell line dependent, ranging from 1.7 to 11.0 nmol/10⁶ cells. SVCT2-knockout cells accumulated 90%-95% less intracellular ascorbate than parental cells. The hypoxic pathway was induced by all three stimuli, and ascorbate reduced this induction. In the SVCT2-knockout cells, ascorbate had limited effect on the hypoxic pathway. This study verifies that intracellular ascorbate is required to suppress the hypoxic pathway. As patient survival is related to an activated hypoxic pathway, increasing intra-tumoral ascorbate may be of clinical interest.