Diagnostic, prognostic, and therapeutic potential of exosomal microRNAs in renal cancer

Renal cell carcinoma (RCC) arises from the tubular epithelial cells of the nephron. It has the highest mortality rate among urological cancers. There are no effective therapeutic approaches and no non-invasive biomarkers for diagnosis and follow-up. Thus, suitable novel biomarkers and therapeutic targets are essential for improving RCC diagnosis/prognosis and treatment. Circulating exosomes such as exosomal microRNAs (Exo-miRs) provide non-invasive prognostic/diagnostic biomarkers and valuable therapeutic targets, as they can be easily isolated and quantified and show high sensitivity and specificity. Exosomes secreted by an RCC can exhibit alterations in the miRs' profile that may reflect the cellular origin and (patho)physiological state, as a ''signature'' or ''fingerprint'' of the donor cell. It has been shown that the transportation of renal-specific miRs in exosomes can be rapidly detected and measured, holding great potential as biomarkers in RCC. The present review highlights the studies reporting tumor microenvironment-derived Exo-miRs with therapeutic potential as well as circulating Exo-miRs as potential diagnostic/prognostic biomarkers in patients with RCC.

A pan-cancer analysis of anti-proliferative protein family genes for therapeutic targets in cancer

The recently discovered APRO (anti-proliferative protein) family encodes a group of trans-membrane glycoproteins and includes 6 members: TOB1, TOB2, BTG1, BTG2, BTG3 and BTG4. The APRO family is reportedly associated with the initiation and progression of cancers. This study aims to undertake a comprehensive investigation of the APRO family of proteins as a prognostic biomarker in various human tumors. We performed a pan-cancer analysis of the APRO family based on The Cancer Genome Atlas (TCGA). With the bioinformatics methods, we explored the prognostic value of the APRO family and the correlation between APRO family expression and tumor mutation burden (TMB), microsatellite instability (MSI), drug sensitivity, and immunotherapy in numerous cancers. Our results show that the APRO family was primarily down-regulated in cancer samples. The expression of APRO family members was linked with patient prognosis. In addition, APRO family genes showed significant association with immune infiltrate subtypes, tumor microenvironment, and tumor cell stemness. Finally, our study also demonstrated the relationship between APRO family genes and drug sensitivity. This study provides comprehensive information to understand the APRO family's role as an oncogene and predictor of survival in some tumor types.

The molecular and cellular anatomy of a fetal programming defect - the impact of low protein diet on the developing kidney

Low nephron number correlates with the development of hypertension and chronic kidney disease later in life. While intrauterine growth restriction caused by maternal low protein diet (LPD) is thought to be a significant cause of reduced nephron endowment in impoverished communities, its influence on the cellular and molecular processes which drive nephron formation are poorly understood. We conducted a comprehensive characterization of the impact of LPD on kidney development using tomographic and confocal imaging to quantify changes in branching morphogenesis and the cellular and morphological features of nephrogenic niches across development. These analyses were paired with single-cell RNA sequencing to dissect the transcriptional changes that LPD imposes during renal development. Differences in the expression of genes involved in metabolism were identified in most cell types we analyzed, yielding imbalances and shifts in cellular energy production. We further demonstrate that LPD impedes branching morphogenesis and significantly reduces the number of pretubular aggregates - the initial precursors to nephron formation. The most striking observation was that LPD changes the developmental trajectory of nephron progenitor cells, driving the formation of a partially committed cell population which likely reflects a failure of cells to commit to nephron formation and which ultimately reduces endowment. This unique profile of a fetal programming defect demonstrates that low nephron endowment arises from the pleiotropic impact of changes in branching morphogenesis and nephron progenitor cell commitment, the latter of which highlights a critical role for nutrition in regulating the cell fate decisions underpinning nephron endowment.

Significance Statement

While a mother's diet and behavior can negatively impact the number of nephrons in the kidneys of her offspring, the root cellular and molecular drivers of these deficits have not been rigorously explored. In this study we use advanced imaging and gene expression analysis in mouse models to define how a maternal low protein diet, analogous to that of impoverished communities, results in reduced nephron endowment. We find that low protein diet has pleiotropic effects on metabolism and the normal programs of gene expression. These profoundly impact the process of branching morphogenesis necessary to establish niches for nephron generation and change cell behaviors which regulate how and when nephron progenitor cells commit to differentiation.

Cell Differentiation Trajectory Predicts Prognosis and Immunotherapeutic Response in Clear Cell Renal Cell Carcinoma

Clear cell renal cell carcinoma (ccRCC) is the main type of malignancy in kidney related to glucose metabolism. Primary single cell culture and single cell sequencing are novel research technologies. In this study, we explored the differentiation status of ccRCC cells and its significance in prognosis and immunotherapeutic response through bioinformatics. We characterized distinct differentiation states and differentiation-related genes (DRGs) in ccRCC cells through single cell RNA sequencing (scRNA-seq) analysis. Combined with bulk RNA-seq data, we classified patients into two clusters and found that this classification was closely correlated with patient prognosis and immunotherapeutic responses. Based on machine learning, we identified a prognostic risk model composed of 14 DRGs, including BTG2, CDKN1A, COL6A1, CPM, CYB5D2, FOSB, ID2, ISG15, PLCG2, SECISBP2, SOCS3, TES, ZBTB16, and ZNF704, to predict the survival rate of patients and then constructed a nomogram model integrating clinicopathological characteristics and risk score for clinical practice. In the study of immune checkpoints, we found that patients in the high-risk group had a disposition to get worse prognosis and better effects of immune checkpoint blocking therapies. Finally, we found the expression level of model DRGs was associated with a tumor-immune microenvironment (TIME) pattern and the response of 83 compounds or inhibitors was significantly different in the two risk groups. In a word, our study highlights the potential contribution of cell differentiation in prognosis judgment and immunotherapy response and offers promising therapeutic options for ccRCC patients.

RNA-binding protein MEX3A controls G1/S transition via regulating the RB/E2F pathway in clear cell renal cell carcinoma

MEX3A is an RNA-binding protein that mediates mRNA decay through binding to 3′ untranslated regions. However, its role and mechanism in clear cell renal cell carcinoma remain unknown. In this study, we found that MEX3A expression was transcriptionally activated by ETS1 and upregulated in clear cell renal cell carcinoma. Silencing MEX3A markedly reduced clear cell renal cell carcinoma cell proliferation in vitro and in vivo. Inhibiting MEX3A induced G1/S cell-cycle arrest. Gene set enrichment analysis revealed that E2F targets are the central downstream pathways of MEX3A. To identify MEX3A targets, systematic screening using enhanced cross-linking and immunoprecipitation sequencing, and RNA-immunoprecipitation sequencing assays were performed. A network of 4,000 genes was identified as potential targets of MEX3A. Gene ontology analysis of upregulated genes bound by MEX3A indicated that negative regulation of the cell proliferation pathway was highly enriched. Further assays indicated that MEX3A bound to the CDKN2B 3′ untranslated region, promoting its mRNA degradation. This leads to decreased levels of CDKN2B and an uncontrolled cell cycle in clear cell renal cell carcinoma, which was confirmed by rescue experiments. Our findings revealed that MEX3A acts as a post-transcriptional regulator of abnormal cell-cycle progression in clear cell renal cell carcinoma.

MicroRNA-934 facilitates cell proliferation, migration, invasion and angiogenesis in colorectal cancer by targeting B-cell translocation gene 2

Colorectal cancer (CRC) is a global public health issue with increasing prevalence. MicroRNA-934 (miR-934) is a kind of non-coding RNA involved in the regulation of diverse cancers. Though previous researches have revealed part of association between miR-934 and CRC, the role of miR-934 in CRC pathogenesis has not been completely explored yet. In this study, we aim to investigate the effect of miR-934 on cell proliferation, migration, invasion and angiogenesis in CRC. Accordingly, miR-934 was found to be over-expressed in SW480 and HCT116 cells, two typical CRC cell lines. Meanwhile, miR-934 knockdown significantly inhibited cell proliferation and induced cell cycle arrest in SW480 and HCT116 cells. It was further validated that miR-934 knockdown displayed an inhibitory effect on cell migration and invasion in SW480 and HCT116 cells. Additionally, miR-934 deficiency markedly decreased VEGF expression in SW480 and HCT116 cells and suppressed capability of CRC cells to promote tube formation in vascular endothelial cells, which suggests the pro-angiogenesis role of miR-934 in vitro. Dual luciferase reporter assay further showed that miR-934 directly bound to B-cell translocation gene 2 (BTG2). BTG2 knockdown reversed the inhibitory effect of miR-934 silencing on cell proliferation, migration, invasion, and angiogenesis in SW480 and HCT116 cells. In summary, this study suggests that miR-934 facilitates CRC progression by targeting BTG2, and further highlights the role of miR-934 in pathogenesis of CRC.

Exosomal microRNA-15a from ACHN cells aggravates clear cell renal cell carcinoma via the BTG2/PI3K/AKT axis

Accumulating studies have indicated that exosomal microRNAs (miRNAs/miRs) can mediate clear cell renal cell carcinoma (ccRCC) at the early stage, but the mechanisms remain to be specified. Here, we investigated the mechanism of exosomal miR-15a in ccRCC. After successful isolation of exosomes from RCC cells, we found that miR-15a was upregulated in ccRCC cells. Moreover, upregulation of miR-15a by pre-miR-15a promoted the proliferation, migration, invasion, and epithelial-mesenchymal transition of ccRCC cells. A luciferase assay revealed that B-cell translocation gene 2 (BTG2) was a target gene of miR-15a and negatively correlated with miR-15a expression. BTG2 was poorly expressed in ccRCC, which reduced the proliferation of ccRCC cells. In addition, overexpression of BTG2 could reverse the promotive effects of miR-15a on ccRCC. Furthermore, BTG2 reduced PI3K/AKT pathway activity. Our results collectively indicated that exosomal miR-15a from RCC cells accelerated cell viability by downregulating BTG2 and promoting the activity of the PI3K/AKT signaling pathway. We demonstrated a novel mechanism by which exosomal miR-15a exerted pro-proliferatory effects on ccRCC, highlighting the potential of exosomal miR-15a as a target for ccRCC prognosis.

LINC01089 inhibits the progression of cervical cancer via inhibiting miR-27a-3p and increasing BTG2

BACKGROUND

Increasing evidence confirms that long non-coding RNA (lncRNA) has a vital impact on the procession of cervical cancer (CC). The present study aimed to investigate the clinical significance of LINC01089 in CC, as well as explore its biological functions and potential molecular mechanisms.

METHODS

A quantitative real-time polymerase chain reaction (qRT-PCR) was utilized to investigate the expression of LINC01089 and miR-27a-3p in CC cells and tissues. Analysis of the correlation between the expression level of LINC01089 and the clinical pathological parameters of CC was then conducted. The human CC cell lines HeLa and SiHa were utilized for transfection to establish a gain-of-function model and loss-of-function models. Western blotting and a qRT-PCR were performed to detect B-cell translocation gene-2 (BTG2) expression in CC cells. Cell counting kit (CCK)-8 and 5-bromo-2-deoxyuridine (BrdU) assays were performed to detect the proliferation of CC cells. The transwell method was employed to evaluate the migration and invasion of CC cells. The interactions between LINC01089 and miR-27a-3p were verified by bioinformatics, a dual luciferase reporter gene experiment and a RNA immunoprecipitation experiment, respectively.

RESULTS

The expression of LINC01089 in CC was markedly down-regulated. The low expression of LINC01089 in CC was closely associated with a larger tumor size and positive lymph node metastasis. Moreover, overexpression of LINC01089 impeded the proliferation and metastasis of CC cells, whereas knockdown of LINC01089 had the opposite biological functions. In terms of mechanism, LINC01089 could sponge miR-27a-3p and indirectly up-regulate BTG2 expression.

CONCLUSIONS

LINC01089, as a tumor suppressor, impedes the development of CC by targeting miR-27a-3p to up-regulate BTG2 expression.

Immunohistochemical Study of NR2C2, BTG2, TBX19, and CDK2 Expression in 31 Paired Primary/Recurrent Nonfunctioning Pituitary Adenomas

This study investigated potential markers for predicting nonfunctioning pituitary adenoma (NFPA) invasion and recurrence by high-throughput tissue microarray analyses. We retrospectively studied two groups of patients: 60 nonrecurrent NFPA cases that included noninvasion and invasion subtypes and 43 recurrent cases that included primary NFPA. A total of 31 paired patient samples were evaluated (12 patients with one surgery and 31 who had undergone two operations, with both tumors analyzed). Expressions of nuclear receptor subfamily 2 group C member 2 (NR2C2), B cell translocation gene 2, T-box-19 (TBX19), and cyclin-dependent kinase 2 (CDK2) in surgically resected specimens were assessed by immunohistochemistry. The relationships between marker expression and clinical characteristics including age, sex, tumor volume, and follow-up time were analyzed. Tumor volume and invasion as well as follow-up time were significantly associated with invasion and recurrence (P < 0.01). Of the 60 nonrecurrent samples, 15/41 and 13/19 showed high NR2C2 expression in the noninvasion and invasion groups, respectively (χ ² =5.287, P = 0.021). NR2C2 was also overexpressed in 43 primary recurrent cases (χ ² =5.433, P = 0.02), whereas CDK2 (χ ² = 11.242, P = 0.001) and TBX19 (χ ² = 4.875, P = 0.027) were downregulated. In the 31 paired samples, NR2C2 was more highly expressed in the recurrent as compared to the primary tumor. High NR2C2 expression was associated with NFPA invasion, recurrence, and progression, while TBX19 and CDK2 were associated with NFPA recurrence.

Gamma Irradiation Upregulates B-cell Translocation Gene 2 to Attenuate Cell Proliferation of Lung Cancer Cells Through the JNK and NF-κB Pathways

Gamma ray can promote cancer cell apoptosis and cell cycle arrest. It is often used in the clinical treatment of tumors, including lung cancer. In this study, we aimed to explore the role of gamma ray treatment and its correlation with BTG2 in cell proliferation, apoptosis, and cell cycle arrest regulation in a lung cancer cell line. A549 cell viability, apoptosis rate, and cell cycle were investigated after gamma ray treatment. We then used siRNA for BTG2 to detect the effect of BTG2 knockdown on the progress of gamma ray-treated lung cancer cells. Finally, we investigated the signaling pathway by which gamma ray might regulate BTG2. We found that gamma ray inhibited A549 cell viability and promoted apoptosis and cell cycle arrest, while BTG2 knockdown could relieve the effect caused by gamma ray on A549 cells. Moreover, we confirmed that the effect of BTG2 partly depends on p53 expression and gamma ray-promoting BTG2 expression through the JNK/NF-κB signaling pathway. Our study assessed the possible mechanism of gamma ray in tumor treatment and also investigated the role of BTG2 in gamma ray therapy. All these findings might give a deep understanding of the effect of gamma ray on the progression of lung cancer involving BTG2.