Functional roles of circular RNAs during epithelial-to-mesenchymal transition.

Cancer has become a major health issue worldwide, contributing to a high mortality rate. Tumor metastasis is attributed to the death of most patients. Epithelial-to-mesenchymal transition (EMT) plays a vital role in inducing metastasis. During EMT, epithelial cells lose their characteristics, such as cell-to-cell adhesion and cell polarity, and cells gain motility, migratory potential, and invasive properties to become mesenchymal stem cells. Circular RNAs (circRNAs) are closely associated with tumor metastasis and patient prognosis, as revealed by increasing lines of evidence. CircRNA is a type of single-stranded RNA that forms a covalently closed continuous loop. CircRNAs are insensitive to ribonucleases and are widespread in body fluids. This work is the first review on EMT-related circRNAs. In this review, we briefly discuss the characteristics and functions of circRNAs. The correlation of circRNAs with EMT has been reported, and we discuss the ways circRNAs can regulate EMT progression through EMT transcription factors, EMT-related signaling pathways, and other mechanisms. This work summarizes current studies on EMT-related circRNAs in various cancers and provides a theoretical basis for the use of EMT-related circRNAs in targeted management and therapy.

Dynamic alteration and prognostic significance of tumor-associated CD68+ and CD68+ PD-L1- macrophages in muscle-invasive bladder cancer treated with neoadjuvant chemotherapy.

BACKGROUND: The current study aimed to investigate the dynamic alteration and prognostic significance of tumor-infiltrating lymphocytes (TILs), tumor-associated macrophages (TAMs), and PD-L1 status of immune cells in muscle-invasive bladder cancer (MIBC) treated with neoadjuvant chemotherapy (NAC). METHODS: Multiplex immunofluorescence staining was performed to examine CD68+ TAM, CD4+ T cell, CD8+ T cell, FOXP3+ Treg cell, and PD-L1 expression in paired MIBC tissues (n = 54) before and after NAC. Patients were then divided into definite responders (DR), (≤pT1) and incomplete responders (IR). RESULTS: There was no significant difference between DR and IR cohorts for the immune cell infiltration levels at the baseline status. Tobacco history was identified to be associated with worse NAC efficacy. CD68+ (stroma area: p = 0.025; tumor area: p = 0.028; total area: p = 0.013) and CD68+ PD-L1- (stroma area: p = 0.035; tumor area: p = 0.013 total area: p = 0.014) TAMs infiltration levels decreased significantly after NAC, while there was no significant difference of CD68+ PD-L1+ and TILs. The infiltration of CD68+ (p = 0.033), CD68+ PD-L1- (p = 0.033), and CD68+ PD-L1+ (p < 0.001) TAMs in stroma area were significantly associated with poorer disease-free survival rate (DFS) of MIBC patients. CONCLUSION: CD68+ and CD68+ PD-L1- TAMs infiltration levels decreased significantly after NAC and pre-treatment TAM infiltration levels were independent prognostic factors for MIBC patients. While there was no sufficient evidence demonstrating that pre-treatment TILs or TAMs could predict response to NAC in MIBC patients.

Disease Management of Clinical Complete Responders to Neoadjuvant Chemotherapy of Muscle-Invasive Bladder Cancer: A Review of Literature.

Muscle-invasive bladder cancer (MIBC) is an aggressive disease requiring active management. Neoadjuvant chemotherapy (NAC) followed by radical cystectomy (RC) is considered the standard treatment paradigm for MIBC patients, which could result in significant perioperative mortality and morbidity, as well as the significant alteration of the quality of life (QOL). Notably, multimodal bladder-preserving treatment strategies have been recommended for highly selected patients. Pathologic complete response (pCR) after NAC is a powerful prognostic indicator of survival for patients with MIBC. Clinical complete response (cCR) is then introduced as a complementary endpoint for pCR to assess disease status preoperatively. Bladder preservation strategy for patients who achieve cCR following NAC is emerging as a new treatment concept. However, the efficiency of the conservative strategy remains controversial. In this state-of-the-art review, we discuss the advantages and limitations of cCR and the feasibility and safety of bladder preservation strategy in highly selected MIBC patients who achieve cCR following NAC. We conclude that a conservative strategy can be considered a reasonable alternative to RC in carefully selected cCR MIBC patients, leading to acceptable oncological outcomes.