Phospho-β-catenin expression in primary and metastatic melanomas and in tumor-free visceral tissues, and associations with expression of PD-L1 and PD-L2

Programmed cell death-ligand 2: new insights in cancer

Immunotherapy has revolutionized cancer treatment, with the anti-PD-1/PD-L1 axis therapy demonstrating significant clinical efficacy across various tumor types. However, it should be noted that this therapy is not universally effective for all PD-L1-positive patients, highlighting the need to expedite research on the second ligand of PD-1, known as Programmed Cell Death Receptor Ligand 2 (PD-L2). As an immune checkpoint molecule, PD-L2 was reported to be associated with patient's prognosis and plays a pivotal role in cancer cell immune escape. An in-depth understanding of the regulatory process of PD-L2 expression may stratify patients to benefit from anti-PD-1 immunotherapy. Our review focuses on exploring PD-L2 expression in different tumors, its correlation with prognosis, regulatory factors, and the interplay between PD-L2 and tumor treatment, which may provide a notable avenue in developing immune combination therapy and improving the clinical efficacy of anti-PD-1 therapies.

Role of β-catenin in PD-L1 expression of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a particular type of tumor connected to Epstein-Barr virus infection, genetic, and environmental factors. It is typically discovered late, with few therapeutic options and poor clinical outcomes. Cellular immune responses can be attenuated when programmed death ligand 1 (PD-L1) and programmed cell death protein 1 (PD-1) are combined. Although PD-1 inhibitors have a different anti-tumor response rate than chemotherapy alone, they can nevertheless considerably outperform chemotherapy in patients with metastatic or recurrent NPC. The nuclear β-catenin can bind to the CD274 promoter region, promoting transcription and upregulating the expression of tumor-specific PD-L1. Separation of β-catenin from E-cadherin and translocation it into nucleus were both aided by β-catenin phosphorylates at the Tyr654 site. Its function in NPC and the expression of PD-L1 have not yet been investigated. This study investigated the predictive significance of PD-L1 and p-β-catenin^Tyr654 expressions in NPC. Our findings indicated that patients with distant metastases or poor prognoses exhibited higher levels of PD-L1 and p-β-catenin^Tyr654 expressions. According to Cox multivariate prognostic analysis, PD-L1 was also an effective indicator for predicting the survival status of patients with NPC. We subsequently demonstrated that PD-L1 transcription and protein production could be downregulated by targeting inhibition of the level of β-catenin in NPC cells. This is for developing the β-catenin or TCF4 inhibitor as a potential new option for immune checkpoint immunosuppression in NPC.

Analysis of microRNA expression in CD133 positive cancer stem‑like cells of human osteosarcoma cell line MG-63

Osteosarcoma (OS) is a primary malignant tumor of bone occurring in young adults. OS stem cells (OSCs) play an important role in the occurrence, growth, metastasis, drug resistance and recurrence of OS. CD133 is an integral membrane glycoprotein, which has been identified as an OSC marker. However, the mechanisms of metastasis, chemoresistance, and progression in CD133(+) OSCs need to be further explored. In this study, we aim to explore differences in miRNA levels between CD133(+) and CD133(-) cells from the MG-63 cell line. We found 20 differentially expressed miRNAs (DEmiRNAs) (16 upregulated and 4 downregulated) in CD133(+) cells compared with CD133(-) cells. Hsa-miR-4485-3p, hsa-miR-4284 and hsa-miR-3656 were the top three upregulated DEmiRNAs, while hsa-miR-487b-3p, hsa-miR-493-5p and hsa-miR-431-5p were the top three downregulated DEmiRNAs. In addition, RT-PCR analysis confirmed that the expression levels of hsa-miR-4284, hsa-miR-4485-3p and hsa-miR-3656 were significantly increased, while the expression levels of hsa-miR-487b-3p, hsa-miR-493-5p, and hsa-miR-431-5p were significantly decreased in CD133(+) cells compared with CD133(-) cells. Moreover, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that predicted or validated target genes for all 20 DEmiRNAs or the selected 6 DEmiRNAs participated in the "PI3K-Akt signaling pathway," "Wnt signaling pathway," "Rap1 signaling pathway," "Cell cycle" and "MAPK signaling pathway". Among the selected six DEmiRNAs, miR-4284 was especially interesting. MiR-4284 knockdown significantly reduced the sphere forming capacity of CD133(+) OS cells. The number of invasive CD133(+) OS cells was markedly decreased after miR-4284 knockdown. In addition, miR-4284 knockdown increased the p-β-catenin levels in CD133(+) OS cells. In conclusion, RNA-seq analysis revealed DEmiRNAs between CD133(+) and CD133(-) cells. MiRNAs might play significant roles in the function of OSCs and could serve as targets for OS treatment. MiR-4284 prompted the self-renewal and invasion of OSCs. The function of miR-4284 might be associated with the Wnt signaling pathway.