Prognostic significance of homozygous deletions and multiple duplications at the CDKN2A (p16INK4a)/ARF (p14ARF) locus in urinary bladder cancer

A novel cuproptosis-related lncRNAs signature predicts prognostic and immune of bladder urothelial carcinoma

Bladder Urothelial Carcinoma (BLCA) remains the most common urinary system tumor, and its prognosis is poor. Cuproptosis is a recently discovered novel cell death involved in the development of tumor cells. However, the use of cuproptosis to predict the prognosis and immunity of Bladder Urothelial Carcinoma remains largely unclear, and this study was designed to verify cuproptosis-related long non-coding RNAs (lncRNAs) to estimate the prognosis and immunity of Bladder Urothelial Carcinoma. In our study, we first defined the expression of cuproptosis-related genes (CRGs) in BLCA, and 10 CRGs were up- or downregulated. We then constructed a co-expression network of cuproptosis-related mRNA and long non-coding RNAs using RNA sequence data from The Cancer Genome Atlas Bladder Urothelial Carcinoma (TCGA-BLCA), clinical features and mutation data from BLCA patients to obtain long non-coding RNAs by Pearson analysis. Afterward, univariate and multivariate COX analysis identified 21 long non-coding RNAs as independent prognostic factors and used these long non-coding RNAs to construct a prognostic model. Then, survival analysis, principal component analysis (PCA), immunoassay, and comparison of tumor mutation frequencies were performed to verify the accuracy of the constructed model, and GO and KEGG functional enrichment analysis was used to verify further whether cuproptosis-related long non-coding RNAs were associated with biological pathways. The results showed that the model constructed with cuproptosis-related long non-coding RNAs could effectively evaluate the prognosis of BLCA, and these long non-coding RNAs were involved in numerous biological pathways. Finally, we performed immune infiltration, immune checkpoint and drug sensitivity analyses on four genes (TTN, ARID1A, KDM6A, RB1) that were highly mutated in the high-risk group to evaluate the immune association of risk genes with BLCA. In conclusion, the cuproptosis-related lncRNA markers constructed in this study have evaluation value for prognosis and immunity in BLCA, which can provide a certain reference for the treatment and immunity of BLCA.

The Undervalued Avenue to Reinstate Tumor Suppressor Functionality of the p53 Protein Family for Improved Cancer Therapy-Drug Repurposing

p53 and p73 are critical tumor suppressors that are often inactivated in human cancers through various mechanisms. Owing to their high structural homology, the proteins have many joined functions and recognize the same set of genes involved in apoptosis and cell cycle regulation. p53 is known as the 'guardian of the genome' and together with p73 forms a barrier against cancer development and progression. The TP53 is mutated in more than 50% of all human cancers and the germline mutations in TP53 predispose to the early onset of multiple tumors in Li-Fraumeni syndrome (LFS), the inherited cancer predisposition. In cancers where TP53 gene is intact, p53 is degraded. Despite the ongoing efforts, the treatment of cancers remains challenging. This is due to late diagnoses, the toxicity of the current standard of care and marginal benefit of newly approved therapies. Presently, the endeavors focus on reactivating p53 exclusively, neglecting the potential of the restoration of p73 protein for cancer eradication. Taken that several small molecules reactivating p53 failed in clinical trials, there is a need to develop new treatments targeting p53 proteins in cancer. This review outlines the most advanced strategies to reactivate p53 and p73 and describes drug repurposing approaches for the efficient reinstatement of the p53 proteins for cancer therapy.

Auxiliary diagnostic value of p16 amplification combined with the detection of heterozygous and homozygous loss for urothelial carcinoma

The present study aimed to investigate the significance of detecting cyclin dependent kinase inhibitor 2A (p16) gene aberrations in the diagnosis of urothelial carcinoma (UC) using fluorescence in situ hybridization (FISH). A total of 77 voided urine specimens from 65 patients with UC and 12 patients with benign urinary disease were recruited into the current study. Under a fluorescence microscope, cells with large and irregular nuclei were assessed for chromosomal aberrations. The positive rate of p16 amplification in UC samples was 32.3% (21/65), which was significantly higher than that in benign urinary disease samples (16.7%, 2/12; P<0.05). Heterozygous and homozygous loss of p16 was identified in 12 (18.5%) and 23 (35.4%) patients with UC, respectively; p16 expression in the remainder of patients was normal. In addition, as tumor stage or grade advanced, the positive rate of p16 aberrations also increased significantly (P<0.05). In conclusion, p16 gene aberrations may serve important roles in the auxiliary diagnosis of UC by FISH and could be utilized to monitor UC progression.

ARF Confers a Context-Dependent Response to Chemotherapy in Muscle-Invasive Bladder Cancer

Muscle-invasive bladder cancer (MIBC) generally responds poorly to treatment and tends to exhibit significant mortality. Here we show that expression of the tumor suppressor p14ARF (ARF) is upregulated in aggressive subtypes of MIBC. Accumulation of ARF in the nucleolus is associated with poor outcome and attenuated response to chemotherapy. In both genetically engineered mouse models and murine xenograft models of human MIBC, we demonstrate that tumors expressing ARF failed to respond to treatment with the platinum-based chemotherapy agent cisplatin. Resistance was mediated in part by the integrin-binding protein ITGB3BP (CENPR) and reflected ARF-dependent impairment of protein translation, which was exaggerated by drug treatment. Overall, our results highlight a context-dependent role for ARF in modulating the drug response of bladder cancer. Cancer Res; 77(4); 1035-46. ©2017 AACR.

Truncated Isoforms of lncRNA ANRIL Are Overexpressed in Bladder Cancer, But Do Not Contribute to Repression of INK4 Tumor Suppressors

The INK4/ARF locus at chromosome 9p21 encoding p14^ARF, p15^INK4B and p16^INK4A is a major tumor suppressor locus, constituting an important barrier for tumor growth. It is frequently inactivated in cancers, especially in urothelial carcinoma (UC). In addition to deletions and DNA hypermethylation, further epigenetic mechanisms might underlie its repression. One candidate factor is the long noncoding RNA ANRIL, which recruits Polycomb proteins (PcG) to regulate expression of target genes in cis and trans. We observed ANRIL overexpression in many UC tissues and cell lines mainly resulting from upregulation of 3’-truncated isoforms. However, aberrant ANRIL expression was neither associated with repression of INK4/ARF genes nor with proliferation activity or senescence. We wondered whether truncated ANRIL isoforms exhibit altered properties resulting in loss of function in cis. We excluded delocalization and performed RNA immunoprecipitation demonstrating interaction between full length or truncated ANRIL and PcG protein CBX7, but not SUZ12 of PRC2. Our data indicate that ANRIL in UC cells may not interact with PRC2, which is central for initializing gene repression. Thus, tissue-specific binding activities between ANRIL and PcG proteins may determine the regulatory function of ANRIL. In conclusion, ANRIL does not play a major role in repression of the INK4/ARF locus in UC.

Germline prognostic markers for urinary bladder cancer: obstacles and opportunities

Urinary bladder cancer is a heterogeneous disease with diverse genetic and environmental risk factors that can influence disease risk or clinical course for recurrence, progression, and survival. Therefore, identification of these factors is paramount for disease prevention and optimal clinical management of bladder cancer patients. Of particular interest is the need to identify molecular biomarkers that can give accurate assessment of tumor biological potential and to predict treatment response. Recent advances in molecular biology, cytogenetic, and genomic research have spurred discovery efforts for novel genetic, epigenetic, and proteomic biomarkers that are prognostic for cancer. This review focuses on some of the important germ line polymorphisms found to be correlated with clinical outcomes in bladder cancer. So far, most of the identified candidate loci were based on prior knowledge of pathogenesis and had not been validated for clinical applications. The future challenges are to analyze the wealth of information from whole-genome studies, to understand the underlying biological mechanisms of these associations, the network of gene-gene and gene-environment interactions, and to apply these markers for the identification of high-risk population for targeted, personalized therapy.

Significant Correlation between Chromosomal Aberration and Nuclear Morphology in Urothelial Carcinoma

We aimed to identify whether there is any correlation between chromosomal/genetic changes, nuclear morphology and the histological grade of urothelial carcinomas of the urinary bladder. Morphometry and multicolour fluorescence in situ hybridisation (FISH) techniques were applied to 250 cells in five low-grade cases and 350 cells in seven high-grade cases of urothelial carcinoma. Compared with low-grade carcinomas, most high-grade cases showed larger and more variable nuclear size, more frequent polysomy of centromere enumeration probes (CEPs) 3, 7 and 17, and the loss of the 9p21 locus. The number of CEP signals in cells was increased as the nuclear area of the cells became larger. Cells with gains in two or more types of CEP had significantly larger nuclei than cells with normal FISH signal patterns. In conclusion, the present study indicates that there was a correlation between nuclear morphology and chromosomal/genetic changes which were related to histological grading. Thus, we show that differences in the chromosomal/genetic aberrations present in low- and high-grade tumours can affect not only nuclear morphology but also the histopathological and clinical behaviour of urothelial carcinomas.

Bladder cancer or bladder cancers? Genetically distinct malignant conditions of the urothelium

Despite the fact that the current histopathologic classification for bladder cancer has led to improved concepts for the clinical management of the disease, key questions with regard to assessment of risk for recurrence and/or progression to invasive disease remain. In addition, response to specific therapies cannot be predicted accurately. Bladder tumors comprise a heterogeneous group with respect to both histopathology and clinical behavior. Thus, it is anticipated that a thorough knowledge and interpretation of the molecular alterations involved in tumor development and progression will lead to greater prognostic and predictive power. This may not only lead to better comprehension of the biology of the disease, but may also lead to the development of novel individualized therapies. Novel means of stratification are urgently needed to provide a new subclassification of urothelial lesions. This review discusses and summarizes the genetic alterations that have been reported in bladder cancer and relates these to the current 2-pathway model for tumor development. The molecular pathogenesis of high-grade noninvasive papillary tumors and of T1 tumors is not yet clear, and possibilities are discussed.

Focal amplifications are associated with high grade and recurrences in stage Ta bladder carcinoma

Urinary bladder cancer is a heterogeneous disease with tumors ranging from papillary noninvasive (stage Ta) to solid muscle infiltrating tumors (stage T2+). The risk of progression and death for the most frequent diagnosed type, Ta, is low, but the high incidence of recurrences has a significant effect on the patients' quality of life and poses substantial costs for health care systems. Consequently, the purpose of this study was to search for predictive factors of recurrence on the basis of genetic profiling. A clinically well characterized cohort of Ta bladder carcinomas, selected by the presence or absence of recurrences, was evaluated by an integrated analysis of DNA copy number changes and gene expression (clone-based 32K, respectively, U133Plus2.0 arrays). Only a few chromosomal aberrations have previously been defined in superficial bladder cancer. Surprisingly, the profiling of Ta tumors with a high-resolution array showed that DNA copy alterations are relatively common in this tumor type. Furthermore, we observed an overrepresentation of focal amplifications within high-grade and recurrent cases. Known (FGFR3, CCND1, MYC, MDM2) and novel candidate genes were identified within the loci. For example, MYBL2, a nuclear transcription factor involved in cell-cycle progression; YWHAB, an antiapoptotic protein; and SDC4, an important component of focal adhesions represent interesting candidates detected within two amplicons on chromosome 20, for which DNA amplification correlated with transcript up-regulation. The observed overrepresentation of amplicons within high-grade and recurrent cases may be clinically useful for the identification of patients who will benefit from a more aggressive therapy.

Frequent deletion and methylation in SH3GL2 and CDKN2A loci are associated with early- and late-onset breast carcinoma

BACKGROUND

This study attempts to understand the association of candidate tumour suppressor genes SH3GL2, CDKN2A (p16-p14) and CDKN2B (p15) in development of early-onset (group A) and late-onset (group B) breast carcinoma (BC).

METHODS

Deletion, methylation, and mutation of the candidate tumour suppressor genes (TSGs) were analysed in 47 group A and 59 group B samples. Immunohistochemical analysis was used to identify the expression status of SH3GL2 and p16. Clinicopathological correlation of the alterations was analysed by the chi-square and log-rank tests.

RESULTS

Higher frequency of overall alterations (46-62%) in SH3GL2 and p16-p14 than p15 (22-26%) indicated their importance in BC. Deletion frequencies were in the following order: group A: p14 (43%) > p16 (42%) > SH3GL2 (38%) > p15 (33%) and group B: p14 (36%) > p16 (33%) > SH3GL2 (31%) > p15 (14%) while, methylation frequencies were: group A: SH3GL2 (34%) > p16 (28%) > p14 (26%) > p15 (15%) and group B: SH3GL2 (36%) > p16 (31%) > p14 (29%) > p15 (15%). Infrequent mutation was observed only in CDKN2A common exon-2. Immunohistochemical analysis showed significant association between expression of SH3GL2 and p16 with their deletion (P = 0.01 and 0.02, respectively) and methylation status (P = 0.007 and 0.01, respectively). In group A, overall alterations of SH3GL2 showed significant association with CDKN2A locus with significant prognostic implications, whereas CDKN2A and CDKN2B loci were associated in both groups.

CONCLUSIONS

The molecular mechanisms involving CDKN2A inactivation seem to follow similar pathway in the pathogenesis of both age groups of BC while significant association of SH3GL2 with CDKN2A might play a synergistic role in the development of group A.