In silico Identification of Hypoxic Signature followed by reverse transcription-quantitative PCR Validation in Cancer Cell Lines

TRPM2-AS promotes ovarian cancer cell proliferation and inhibits cell apoptosis by upregulating the nearby gene TRPM2 via miR-6764-5p

Ovarian cancer (OC) becomes a fatal gynecologic malignant cancer in females worldwide. Target therapy is a promising therapeutical choice for patients with OC, and identifying biomarkers and exploring molecular mechanisms are necessary. In this study, the functions and mechanism of long noncoding RNA transient receptor potential cation channel subfamily M member 2 antisense RNA (TRPM2-AS) in OC were explored. TRPM2-AS expression in OC cells was analyzed utilizing reverse transcription quantitative polymerase chain reaction (RT-qPCR). Cell counting kit-8 (CCK-8) and colony forming assays were carried out to explore the influence of TRPM2-AS on OC cell viability and proliferation. Cell apoptosis was detected using TdT-mediated dUTP Nick-End labeling (TUNEL) and flow cytometry analysis. Protein expression of apoptotic markers was subjected to western blotting. RNA pulldown or luciferase reporter assays were applied to explore the interaction between TRPM2-AS and miR-6764-5p or the binding of miR-6764-5p and TRPM2. The results showed that TRPM2-AS is highly expressed in OC cells and was mainly localized in cytoplasm. TRPM2-AS depletion suppressed OC cell viability and proliferation while increasing cell apoptotic rate. TRPM2 displayed a high level in OC cells and was positively regulated by TRPM2-AS. TRPM2-AS interacted with miR-6764-5p and thereby upregulated TRPM2 expression. In addition, TRPM2 overexpression reversed the repressive impact of TRPM2-AS depletion on malignant OC cellular process. In conclusion, TRPM2-AS promotes OC cell viability and proliferation while enhancing cell apoptosis through interaction with miR-6764-5p to regulate TRPM2 level.

GAPDH: unveiling its impact as a key hypoxia-related player in head and neck squamous cell carcinoma tumor progression, prognosis, and therapeutic potential

Head and neck squamous cell carcinoma (HNSCC), characterized by hypoxia patterns, ranks as the sixth most prevalent malignant tumor worldwide. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) plays a role in oncogenesis under hypoxic conditions in various cancers. However, its precise function in HNSCC, especially under varied hypoxic conditions, including at high altitudes, remains unclear. Elevated GAPDH mRNA and protein levels in HNSCC relative to normal tissues have been demonstrated through data from The Cancer Genome Atlas (TCGA), GSE29330, and the Human Protein Atlas (P<0.05). This elevation was further confirmed through in vitro experiments utilizing two HNSCC cell lines and a normal oral mucosal epithelial cell line. Additionally, data from TCGA and GSE41613 reveal a correlation between elevated GAPDH expression and diminished overall and progression-free survival in patients (P<0.05). Subsequent analysis identifies GAPDH as an independent risk factor for HNSCC (P<0.05). Using the ESTIMATE and single-sample gene set enrichment analysis (ssGSEA) algorithms, high GAPDH expression was found to be associated with reduced immune scores and diminished anti-tumor cell infiltration, such as CD8+ T cells, in TCGA and GSE41613 datasets (P<0.05). Analysis of single-cell RNA sequencing data from GSE139324 suggests that elevated GAPDH expression hinders communication between plasmacytoid dendritic cells and mast cells (P<0.05). Furthermore, in the TCGA and GSE41613 datasets, GAPDH's biological function is closely tied to hypoxia through Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Variation Analysis (GSVA) analyses. Moreover, its expression is linked to one cuproptosis-related gene, five N6-methyladenosine-related genes, six immune checkpoint genes, and pivotal pathways such as MYC and E2F (P<0.05). GAPDH showed excellent predictive value in estimating the efficacy of immunotherapy and 11 anti-tumor drugs (e.g., cisplatin) (P<0.05), using TIDE and pRRophetic algorithms on the TCGA and GSE41613 datasets. Under 1% O2 in vitro, HNSCC cells show elevated GAPDH expression, leading to decreased apoptosis and increased migration, clonogenicity, invasiveness, and resistance to cisplatin (P<0.05). At 5% O2, these effects persisted, albeit less pronouncedly. Inhibiting GAPDH reversed these effects under all oxygen concentrations (P<0.05). Overall, our findings reveal GAPDH as a key hypoxia-related player influencing tumor progression, prognosis, and therapeutic potential in HNSCC.

MiR-455-3p mediates PPARα through UBN2 to promote apoptosis and autophagy in acute myeloid leukemia cells

Acute myeloid leukemia (AML) is one of the deadliest hematologic malignancies, and its targeted therapy has developed slowly. The molecular mechanism of the pathophysiology of the disease remains to be clarified. The aim of our study was to probe the specific regulatory mechanism of miR-455-3p in AML. This study measured the levels of miR-455-3p and ubinuclein-2 (UBN2) in AML cell lines, evaluated cell viability with CCK-8, used flow cytometry to estimate the cell cycle and apoptosis, detected cell apoptosis and autophagy-related protein levels by Western blotting, and added 50 μM chloroquine (CQ) to evaluate the relationship between autophagy and AML. In animal experiments, HL-60 cells were injected into male non-obese diabetic/severe combined immunodeficiency disease (NOD/SCID) mice through the tail vein to determine survival time and observe the degree of liver and spleen damage in the mice. miR-455-3p was prominently reduced in the peripheral blood and AML cell lines, and UBN2 showed high expression. The transfected miR-455-3p mimic effectively restrained the activity of AML cells, whereas overexpression of UBN2 or the addition of the autophagy inhibitor CQ reversed the effect of miR-455-3p. The interaction between UBN2 and peroxisome proliferator-activated receptor alpha (PPARα) was confirmed by coimmunoprecipitation, and overexpression of PPARα reversed the promoting effect of UBN2 knockdown on apoptosis and autophagy in AML cells. In conclusion, miR-455-3p mediates PPARα protein expression through UBN2, exacerbating AML cell apoptosis and autophagy. This study found that miR-455-3p plays an important role in AML cell apoptosis and autophagy, which may provide novel insights for the treatment of AML diseases.