KCNQ1OT1 sponges miR-34a to promote malignant progression of malignant melanoma via upregulation of the STAT3/PD-L1 axis

MicroRNAs as regulators of immune checkpoints in cancer immunotherapy: targeting PD-1/PD-L1 and CTLA-4 pathways

Immunotherapy has revolutionized cancer treatment by harnessing the power of the immune system to eliminate tumors. Immune checkpoint inhibitors (ICIs) block negative regulatory signals that prevent T cells from attacking cancer cells. Two key ICIs target the PD-1/PD-L1 pathway, which includes programmed death-ligand 1 (PD-L1) and its receptor programmed death 1 (PD-1). Another ICI targets cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). While ICIs have demonstrated remarkable efficacy in various malignancies, only a subset of patients respond favorably. MicroRNAs (miRNAs), small non-coding RNAs that regulate gene expression, play a crucial role in modulating immune checkpoints, including PD-1/PD-L1 and CTLA-4. This review summarizes the latest advancements in immunotherapy, highlighting the therapeutic potential of targeting PD-1/PD-L1 and CTLA-4 immune checkpoints and the regulatory role of miRNAs in modulating these pathways. Consequently, understanding the complex interplay between miRNAs and immune checkpoints is essential for developing more effective and personalized immunotherapy strategies for cancer treatment.

Transcriptional factor BRD4 promotes the stemness of esophageal cancer by activating the nuclear PD-L1/RelB axis

Esophageal cancer (EC) is a prevalent malignancy associated with therapeutic resistance and poor prognosis. This study investigates the role of programmed death-ligand 1 (PD-L1) in esophageal cancer stem cell (ECSC) formation. ECSCs were enriched and characterized using various assays. We found that both PD-L1 and bromodomain-containing protein 4 (BRD4) were upregulated in ECSCs, promoting their stemness. Inhibiting BRD4 suppressed ECSC markers expression and sphere formation. Furthermore, BRD4 inhibitors downregulated membrane and nuclear PD-L1 levels, with knockdown of PD-L1 inhibiting ECSC formation. PD-L1 degraders also affected PD-L1 and its downstream effector RelB expression. Moreover, inhibiting RelB influenced sphere formation through interleukin-6 expression. This study reveals the critical role of the BRD4/nuclear PD-L1/RelB axis in ECSC formation, highlighting nuclear PD-L1 as a potential immunotherapeutic target for refractory EC.

Biological role of long non-coding RNA KCNQ1OT1 in cancer progression

Long non-coding RNAs (lncRNAs) are a type of RNAs that are more than 200 nucleotides without protein-coding potential. In recent years, more and more attention has been paid to the role of lncRNAs in cancer pathogenesis. LncRNA KCNQ1 overlapping transcript 1 (KCNQ1OT1) is located on chromosome 11p15.5 with a total length of 91 kb and is highly expressed in various malignancies, which is closely related to tumor growth, lymph node metastasis, survival cycle and recurrence rate. In addition, KCNQ1OT1 is involved in the regulation of PI3K/AKT and Wnt/β-catenin signaling pathways. In this review, the mechanism and related progress of KCNQ1OT1 in different cancers were reviewed. It was found that KCNQ1OT1 can stabilize mRNA expression through sponging miRNA, which not only induced tumor cell proliferation, migration, invasion, drug resistance, epithelial-mesenchymal transition (EMT) and inhibited cell apoptosis in vitro, but also promoted tumor growth and metastasis in vivo. Therefore, as a new biomarker and therapeutic target, KCNQ1OT1 has broad prospects for the diagnosis and treatment of different cancers.

Childhood sunburn and risk of melanoma and non-melanoma skin cancer: a Mendelian randomization study

Previous evidence has suggested that childhood sunburn could be a risk factor for cutaneous malignant melanoma (MM) and non-melanoma skin cancer (NMSC). However, existing observational studies could not reveal the causal associations genetically. This study aimed to investigate whether there was a genetic causal relationship between childhood sunburn and skin cancers. Univariable Mendelian randomization (MR) and Causal Analysis Using Summary Effect analysis was carried out for causal estimates and evaluation for the horizontal pleiotropy. Multivariable MR and the mediation effects analysis were used to test whether the causal associations were mediated by potential confounders. A suggestively significant causal association between childhood sunburn and MM was indicated (OR = 4.74; 95% CI: 1.31-17.19; p = 1.79E-02). Genetically predicted childhood sunburn was significantly associated with increased risk of overall melanoma in situ (MIS) (OR = 4.02; 95% CI: 2.00-8.08; p = 9.40E-05), MIS of face (OR = 18.28; 95% CI: 5.28-63.35; p = 4.59E-06), and MIS of trunk (OR = 7.05; 95% CI: 2.06-24.13; p = 1.88E-03). Similar trends were found for childhood sunburn and NMSC (OR = 8.16; 95% CI: 6.07-10.99; p = 1.53E-20), including both basal cell carcinoma (BCC) (OR = 3.76; 95% CI:2.96-4.77; p = 2.19E-08) and squamous cell carcinoma (SCC) (OR = 7.44; 95% CI: 5.09-10.87; p = 2.19E-08). After adjustment for hair and skin color, facial ageing, vitamin D levels, body mass index, alcohol consumption, and smoking status, childhood sunburn showed an independent association with MIS, MIS of face, MIS of trunk, as well as NMSC, including both BCC and SCC. Mediation analysis showed no significant mediation effect. This study demonstrated a causal relationship between childhood sunburn and the risk of both MM and NMSC, which suggested that enhanced screening and prevention for childhood sunburn could contribute to the early detection and decreased risk of MM and NMSC.

A novel mitochondria-targeting compound exerts therapeutic effects against melanoma by inducing mitochondria-mediated apoptosis and autophagy in vitro and in vivo

Melanoma is the most invasive skin cancer, with a high mortality rate. However, existing therapeutic drugs have side effects, low reactivity, and lead to drug resistance. As the power source in cells, mitochondria play an important role in the survival of cancer cells and are an important target for tumor therapy. This study aimed to develop a new anti-melanoma compound that targets mitochondria, evaluate its effect on the proliferation and metastasis of melanoma cells, and explore its mechanism of action. The novel mitochondria-targeting compound, SCZ0148, was synthesized by modifying the structure of cyanine. Then, A375 and B16 cells were incubated with different concentrations of SCZ0148, and different doses of SCZ0148 were administered to A375 and B16 xenograft zebrafish. The results showed that SCZ0148 targeted mitochondria, had dose- and time-dependent effects on the proliferation of melanoma cell lines, and had no obvious side effects on normal cells. In addition, SCZ0148 induced melanoma cell apoptosis through the reactive oxygen species-mediated mitochondrial pathway of apoptosis and promoted autophagy. SCZ0148 significantly inhibited the migration of melanoma cells via a matrix metalloprotein 9-mediated pathway. Similarly, SCZ0148 inhibited melanoma cell proliferation in a concentration-dependent manner in vivo. In summary, SCZ0148 may be a novel anti-melanoma compound that targets mitochondria.

p53/MicroRNA-34 axis in cancer and beyond

Cancer is serious endangers human life. After a long period of research and accumulation, people's understanding of cancer and the corresponding treatment methods are constantly developing. p53 is an important tumor suppressor gene. With the more in-depth understanding of the structure and function of p53, the more importance of this tumor suppressor gene is realized in the process of inhibiting tumor formation. MicroRNAs (miRNAs) are important regulatory molecules with a length of about 22nucleotides (nt), which belong to non-coding RNA and play an important role in the occurrence and development of tumors. miR-34 is currently considered to be a master regulator of tumor suppression. The positive feedback regulatory network formed by p53 and miR-34 can inhibit the growth and metastasis of tumor cells and inhibit tumor stem cells. This review focuses on the latest progress of p53/miR-34 regulatory network, and discusses its application in tumor diagnosis and treatment.