The function and mechanisms of action of circular RNAs in Urologic Cancer.

Kidney, bladder, and prostate cancer are the three major tumor types of the urologic system that seriously threaten human health. Circular RNAs (CircRNAs), special non-coding RNAs with a stabile structure and a unique back-splicing loop-forming ability, have received recent scientific attention. CircRNAs are widely distributed within the body, with important biologic functions such as sponges for microRNAs, as RNA binding proteins, and as templates for regulation of transcription and protein translation. The abnormal expression of circRNAs in vivo is significantly associated with the development of urologic tumors. CircRNAs have now emerged as potential biomarkers for the diagnosis and prognosis of urologic tumors, as well as targets for the development of new therapies. Although we have gained a better understanding of circRNA, there are still many questions to be answered. In this review, we summarize the properties of circRNAs and detail their function, focusing on the effects of circRNA on proliferation, metastasis, apoptosis, metabolism, and drug resistance in kidney, bladder, and prostate cancers.

The expression and prognostic value of transporter 1, ATP binding cassette subfamily B member in clear cell renal cell cancer with experimental validation.

Transporter associated with antigen processing 1(TAP1) serves as a protein to transport antigenic peptides from the surface of the endoplasmic reticulum to the lumen of the endoplasmic reticulum when the antigens are presented by major histocompatibility complex type I (MHC-I), which has been identified to play a critical role in antigen presentation in innate immunity. In tumors, the role of TAP1 seems to remain controversial. On the one hand, given the role of TAP1 in antigen presentation, it is indicated that high TAP1 expression corresponds to the emergence of more neoantigens epitopes that facilitate the recognition for phagocytes, T cells and other cells. On the other hand, the genetic ablation of transporter associated with antigen processing (TAP) results in the presentation of new class I-restricted epitopes encoded in house-keeping products. Opposite result has been revealed by studies in other tumors suggest, which implies a more complex function of TAP1. Therefore, it's significant to clarify the role of TAP1 in clear cell renal cell carcinoma (ccRCC). In this study, we found the elevated expression levels in mRNA and protein of TAP1 in ccRCC tissues, which indicated a relatively worse prognosis. Transwell assay and Scratch assay in vitro demonstrated the promotive role of TAP1 in ccRCC migration as well as a significant role in metastasis. And the increased expression of TAP1 resulted in more immune cells infiltrated in cancer tissues. TAP1 was also demonstrated to be related to immune regulator genes, as gene set enrichment analysis (GSEA) indicated its significant role in immune regulation. The results of CancerSEA indicated the positive association of the high-level TAP1 expression with epithelial-mesenchymal transition (EMT) and the inverse association with Cell Cycle. The effective drugs were also predicted based on TAP1 expression, of which the high level was indeed associated with resistance to multiple drugs, but some effective drugs still identified based on high TAP1 expression. According to the analysis of various databases, the role of TAP1 in ccRCC was explored, especially in relationship of TAP1 with tumor microenvironment. These results indicate that TAP1 can serve as a potential target for treatment of ccRCC.

Enhancing KDM5A and TLR activity improves the response to immune checkpoint blockade.

Immune checkpoint blockade (ICB) therapies are now established as first-line treatments for multiple cancers, but many patients do not derive long-term benefit from ICB. Here, we report that increased amounts of histone 3 lysine 4 demethylase KDM5A in tumors markedly improved response to the treatment with the programmed cell death protein 1 (PD-1) antibody in mouse cancer models. In a screen for molecules that increased KDM5A abundance, we identified one (D18) that increased the efficacy of various ICB agents in three murine cancer models when used as a combination therapy. D18 potentiated ICB efficacy through two orthogonal mechanisms: (i) increasing KDM5A abundance, which suppressed expression of the gene PTEN (encoding phosphatase and tensin homolog) and increased programmed cell death ligand 1 abundance through a pathway involving PI3K-AKT-S6K1, and (ii) activating Toll-like receptors 7 and 8 (TLR7/8) signaling pathways. Combination treatment increased T cell activation and expansion, CD103+ tumor-infiltrating dendritic cells, and tumor-associated M1 macrophages, ultimately enhancing the overall recruitment of activated CD8+ T cells to tumors. In patients with melanoma, a high KDM5A gene signature correlated with KDM5A expression and could potentially serve as a marker of response to anti-PD-1 immunotherapy. Furthermore, our results indicated that bifunctional agents that enhance both KDM5A and TLR activity warrant investigation as combination therapies with ICB agents.

PHF23 (plant homeodomain finger protein 23) negatively regulates cell autophagy by promoting ubiquitination and degradation of E3 ligase LRSAM1.

Autophagy is a multistep process that involves the degradation and digestion of intracellular components by the lysosome. It has been proved that many core autophagy-related molecules participate in this event. However, new component proteins that regulate autophagy are still being discovered. At present, we report PHF23 (PHD finger protein 23) with a PHD-like zinc finger domain that can negatively regulate autophagy. Data from experiments indicated that the overexpression of PHF23 impaired autophagy, as characterized by decreased levels of LC3B-II and weakened degradation of endogenous and exogenous autophagic substrates. Conversely, knockdown of PHF23 resulted in opposite effects. Molecular mechanism studies suggested that PHF23 interacts with LRSAM1, which is an E3 ligase key for ubiquitin-dependent autophagy against invading bacteria. PHF23 promotes the ubiquitination and proteasome degradation of LRSAM1. We also show that the PHD finger of PHF23 is a functional domain needed for the interaction with LRSAM1. Altogether, our results indicate that PHF23 is a negative regulator associated in autophagy via the LRSAM1 signaling pathway. The physical and functional connection between the PHF23 and LRSAM1 needs further investigation.

[The preparation and identification on monoclonal antibody to platelet-derived growth factor receptor].

OBJECTIVE: Through genetic engineering to produce the fusion protein of glutathione S-transferase (GST) linked to amino-terminal end of platelet-derived growth factor receptor (PDGFR), and to prepare the bioactive monoclonal antibody. METHODS: With taking GST-PDGFR-N fusion protein as immunogen, the anti-PDGFR monoclonal antibody was produced by using the hybridoma technique, of which then the antigen binding characteristic was identified by indirect enzyme-linked immunosorbent assay (ELISA), Western blot and immunohistochemistry methods. RESULTS: Two cell strains of hybridoma were obtained and named as 3B12F5 and 3C6H7C11 which secreted the anti-PDGFR monoclonal antibody, of which the class and subtype identification demonstrated both strains to produce all type of IgG1. The indirect ELISA result showed that the titers of ascites fluid which two hybridoma induced were 1 : 102400 and 1 : 25600. Western blot demonstrated that the two antibodies could recognize specifically the immunogen on PDGFR and U251 cell line. The cell immunohistochemistry proved that the antibody could recognize the expressed PDGFR antigens of neurogliocytoma U251 and bladder carcinoma BIU87 cell lines. CONCLUSION: We prepare successfully the PDGFR monoclonal antibody and provide a useful tool for researching on the PDGFR expression and clinical detection.