Alterations of p53 and Rb Pathways Are Associated with High Proliferation in Bladder Urothelial Carcinomas

Bioinformatics analysis proposes a possible role for long noncoding RNA MIR17HG in retinoblastoma

BACKGROUND

Retinoblastoma (RB) is the most common prevalent intraocular malignancy among infants and children, particularly in underdeveloped countries. With advancements in genomics and transcriptomics, noncoding RNAs have been increasingly utilized to investigate the molecular pathology of diverse diseases.

AIMS

This study aims to establish the competing endogenous RNAs network associated with RB, analyse the function of mRNAs and lncRNAs, and finds the relevant regulatory network.

METHODS AND RESULTS

This study establishes a network of competing endogenous RNAs by Spearman correlation analysis and prediction based on RB patients and healthy children. Enrichment analyzes based on Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes are conducted to analyze the potential biological functions of lncRNA and mRNA networks. Weighted gene co-expression network analysis (WGCNA) is employed to identify gene cluster modules exhibiting the strongest correlation with RB. The results indicate a significant correlation between the lncRNA MIR17HG (R = .73, p = .02) and the RB phenotype. ceRNA networks reveal downstream miRNAs (hsa-mir-425-5p and hsa-mir455-5p) and mRNAs (MDM2, IPO11, and ITGA1) associated with MIR17Hg. As an inhibitor of the p53 signaling pathway, MDM2 can suppress the development of RB.

CONCLUSION

In conclusion, lncRNAs play a role in RB, and the MIR17HG/hsa-mir-425-5p/MDM2 pathway may contribute to RB development by inhibiting the p53 signaling pathway.

The inclusion of nuclear area improves the Paris system for reporting urinary cytology

OBJECTIVE

The Paris System for Reporting Urinary Cytology (TPS) is a well-known urinary diagnostic model; however, occasional false-positives are a problem. To address this issue, we developed an improved algorithm (IA), based on additional cytological features, for TPS diagnosis.

METHODS

Cytological features were evaluated in 29 hard-to-classify cases, including 22 malignant cases and seven benign cases, using image analysis. The optimal IA was determined using the area under the receiver operating characteristic curve as an index. Re-evaluation was performed by applying measured values to the TPS and IA algorithms.

RESULTS

Using TPS, 12 of the 22 malignant cases were reassigned to a more appropriate category, and the remaining 10 malignant cases remained hard-to-classify. Two of the seven benign cases were classified as suspicious for high-grade urothelial carcinoma, and the remaining five benign cases remained in the original category. The IA, which included nuclear area as a parameter, showed the same diagnostic sensitivity as TPS, and three of the seven benign cases were reassessed as negative. Thus, the positive and negative predictive values of the IA were higher than those of TPS (84.6% and 100% vs 75.9% and 0%).

CONCLUSIONS

The newly developed IA is a practical algorithm with which to address the limitations of TPS and thus may contribute to improved diagnostic accuracy.

Persistent γ-H2AX formation and expression of stem cell markers in N-butyl-N-(4-hydroxybutyl)nitrosamine-induced bladder carcinogenesis in rats

We investigated γ-H2AX formation, a biomarker of DNA damage, and expression of stem cell markers (SCMs), including cytokeratin 14, aldehyde dehydrogenase 1A1 (ALDH1A1), and CD44, in the development of rat bladder tumors induced by short-term administration of N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN). Histopathological examination showed that diffuse simple hyperplasia of the bladder urothelium induced by BBN recovered to the normal-appearing urothelium after withdrawal, whereas focal proliferative lesions were newly developed and subsequently progressed to benign papilloma and carcinoma. Immunohistochemical analysis revealed that BBN-induced γ-H2AX formation and ALDH1A1 and CD44 expression persisted at higher levels in the normal-appearing urothelium than those in the control group for long periods after withdrawal. Since persistent chronic inflammation was observed even after withdrawal, targeted gene expression analysis of inflammation-related factors revealed 101 genes, including Stat3 and Myc, that showed persistent high expression. Pathway analysis suggested that Stat3 and/or Myc activation may be associated with SCM expression. We focused on hepatocyte growth factor (Hgf), one of the genes predicted in relation to Stat3/Myc, and confirmed that HGF-positive cells increased by BBN persisted in the normal-appearing urothelium after withdrawal and colocalized with γ-H2AX and SCMs. These results suggested that the long-term persistence of γ-H2AX formation and SCM expression, which occurred during the early stages of bladder tumorigenesis, is not a transient response to exposure and might contribute to bladder tumorigenesis. Although further studies are needed, BBN-induced rat bladder tumors may originate from focal hyperplasia arising from SCM-positive cells via activation of the STAT3/MYC pathway after DNA damage involving γ-H2AX formation.

Overexpression of the PPAR-γ protein in primary Ta/T1 non-muscle-invasive urothelial carcinoma

Peroxisome proliferator-activated receptor-γ (PPAR-γ) is a well-known nuclear receptor that is activated in the nucleus to regulate several transcription factors. Its expression patterns have been examined in various types of cancer. The present study investigated the expression patterns of PPAR-γ in non-muscle-invasive urothelial carcinoma. The expression rates of PPAR-γ, p53 and Ki-67 were compared to determine whether PPAR-γ may be considered as an immunobiomarker for bladder cancer. The intensity and extent of PPAR-γ expression were evaluated in 79 cases of non-muscle-invasive urothelial carcinoma (30 cases of papillary carcinoma low-grade, 30 cases of high-grade and 19 cases of carcinoma in situ) and 30 non-malignant cases. The nuclear overexpression of PPAR-γ was frequently observed in non-muscle-invasive urothelial carcinoma (63/79 cases) but was rarely detected in non-malignant cases (2/30 cases). The histological proliferation types of non-muscle-invasive urothelial carcinoma revealed that PPAR-γ was more frequently overexpressed in papillary carcinoma (54/60 cases) than in carcinoma in situ (9/19 cases). Immunohistochemical staining demonstrated that PPAR-γ was more useful as an immunobiomarker than p53 or Ki-67 (diagnostic odds ratios; 55.13, 16.82 and 11.13, respectively). In summary, this study demonstrated that the expression patterns of PPAR-γ were associated with histological proliferation type and that PPAR-γ was expressed in the nuclei of papillary carcinoma cells. These findings suggested that immunohistochemical staining for PPAR-γ may be used to comprehensively detect non-muscle-invasive urothelial carcinoma.

Immunohistochemical Expression of Retinoblastoma Gene Product and p53 Protein in Transitional Cell Carcinoma of the Urinary Bladder and its Relationship to Different Clinicopathological Parameters

BACKGROUND: Carcinoma of urinary bladder is one of the most common malignancies worldwide and constitutes a major health problem. Multiple risk factors are associated with this tumor and its prognosis will depend on different clinicopathological parameters. Over expression of P53 protein and mutant Rb gene is associated with more aggressive clinical and histopathological features of the tumor such as advanced stage and higher grade. AIM: The immunohistochemical expression of Rb gene and P53 gene will be assessed through their protein products in transitional cell carcinoma (TCC) of the urinary bladder and then will be correlated with other well-known risk factors and prognostic parameters of bladder TCC, such as grading, tumor size, smoking, alcohol drinking, and family history. METHODS: Patients were recruited from the uro-surgical department/Surgical Subspecialties Teaching Hospital during the period from November 2020 through April 2021. In this study, patients enrolled were those suspected to have bladder carcinoma. The work up included a full history and clinical examination. Surgical samples were taken from the patients for histopathological evaluation; the study’s samples represented either endoscopic cup biopsy, transurethral resection of the tumor, or radical cystectomy. Sections obtained from these samples were stained with the conventional hematoxylin and eosin stain. Then, immunohistochemical staining for P53 and pRB was applied only for patients diagnosed with TCC. RESULTS: The differences between low-grade and high-grade tumors regarding pRb percentage score were statistically significant (p = 0.026), but were not significant regarding the intensity score (p = 0.094). There were significant correlations between tumor stage and both pRb intensity and percentage scores (p = 0.044 and 0.042, respectively). Differences between low-grade and high-grade tumors regarding p53 intensity score were significant (p = 0.022). The differences between low-grade and high-grade tumors regarding p53 percentage score were significant (p = 0.049). The differences between different tumor stages regarding p53 intensity score were significant (p = 0.018). The differences between different tumor stages regarding P53 percentage score were significant (p = 0.019). CONCLUSIONS: Tumor’s grade was found to be correlated with the tumor stage with no correlation with the age, gender, smoking, family history of TCC, history of urinary tract infection, bladder stones, nor the recurrence of the tumor. The pRb intensity and the percentage scores were correlated to each other and to tumor’s grade and stage, except for the pRb intensity which showed no correlation with the tumor’s grade. The P53 intensity and percentage scores were correlated to each other and also to tumor’s grade and stage, so that P53 is over-expressed in tumors with higher grade and stage.

RB1 and TP53 co-mutations correlate strongly with genomic biomarkers of response to immunity checkpoint inhibitors in urothelial bladder cancer

Background

Muscle invasive urothelial bladder carcinoma (MIBC) present RB1 and TP53 somatic alterations in a variable percentage of tumors throughout all molecular subtypes. MIBCs with neuroendocrine features have a high response rate to immunity checkpoint inhibitors (ICIs). Whether the presence of somatic co-alterations in these 2 genes in MIBCs is relevant to their responsiveness to ICIs is not known.

Methods

The potential correlation of different genomic biomarkers of response to ICIs like tumor mutational burden (TMB), single nucleotide variants (SNV) predicted neoantigens, DNA damage response (DDR) genes, DNA somatic signatures and TILs infiltrate was explored in patients with somatic co-alterations in RB1 and TP53 (RB1&TP53) as compared with patients with no alterations in any (double wild type, DWT) or with alterations in just one of the 2 genes. The Cancer Genome Atlas (TCGA) pancancer BLCA dataset of cystectomy specimens (n = 407) with mutation, copy number alterations and transcriptomic (RNA sequencing) data as well as the IMVigor 210 study (n = 348) of metastatic urothelial bladder cancers treated with atezolizumab (PD-L1 inhibitor) with clinical response data containing transcriptomic (RNA sequencing), along with a subset (n = 274) with mutation and copy number data were used for this purpose. A novel tumor microenvironment metascore (TMM) was developed based in a LASSO regularized Cox model with predictive and prognostic ability.

Results

Samples with co-altered RB1&TP53: a) were enriched in immunity effectors (CD8 cytotoxic lymphocytes, NK cells) and display higher scores of a T cell inflamed signature; b) have a higher TMB, higher number of SNV predicted neoantigens and higher TILs fractions; c) have a higher number of DDR mutated and deep deleted DDR genes; d) have DNA somatic signatures 2 and 13 related to APOBEC mutagenesis. Using the IMVigor 210 dataset, RB1&TP53 samples had the highest response rate to atezolizumab and a strong correlation with TMB and TMM. The consensus molecular subtype classification in the IMVigor 210 dataset showed a significant correlation with both the response to treatment (p = 0.001, Chisquare) and the presence of RB1 and TP53 genomic alterations (p < 0.001, Chisquare).

Conclusions

RB1&TP53 co-alterations are strongly associated with genomic biomarkers of response to ICIs in MIBCs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08078-y.

Stepwise crosstalk between aberrant Nf1, Tp53 and Rb signalling pathways induces gliomagenesis in zebrafish

The molecular pathogenesis of glioblastoma indicates that RTK/Ras/PI3K, RB and TP53 pathways are critical for human gliomagenesis. Here, several transgenic zebrafish lines with single or multiple deletions of nf1, tp53 and rb1 in astrocytes, were established to genetically induce gliomagenesis in zebrafish. In the mutant with a single deletion, we found only the nf1 mutation low-efficiently induced tumour incidence, suggesting that the Nf1 pathway is critical for the initiation of gliomagenesis in zebrafish. Combination of mutations, nf1;tp53 and rb1;tp53 combined knockout fish, showed much higher tumour incidences, high-grade histology, increased invasiveness, and shortened survival time. Further bioinformatics analyses demonstrated the alterations in RTK/Ras/PI3K, cell cycle, and focal adhesion pathways, induced by abrogated nf1, tp53, or rb1, were probably the critical stepwise biological events for the initiation and development of gliomagenesis in zebrafish. Gene expression profiling and histological analyses showed the tumours derived from zebrafish have significant similarities to the subgroups of human gliomas. Furthermore, temozolomide treatment effectively suppressed gliomagenesis in these glioma zebrafish models, and the histological responses in temozolomide-treated zebrafish were similar to those observed in clinically treated glioma patients. Thus, our findings will offer a potential tool for genetically investigating gliomagenesis and screening potential targeted anti-tumour compounds for glioma treatment.

High expression of PIG11 correlates with poor prognosis in gastric cancer

P53-induced gene 11 (PIG11) is an early transcription-related target of p53 that is involved in cell apoptosis and tumor development. However, its biological function in gastric cancer (GC) tissues and relationship with the prognosis of patients with GC have remained elusive. In the present retrospective study, 60 fresh and 790 paraffin-embedded samples of GC were obtained from the Affiliated Hospital of Nantong University (Nantong, China) with complete clinical data from all patients. Reverse transcription-quantitative PCR and tissue microarray-immunohistochemical analysis were used to determine the expression of PIG11 in the respective GC tissues. A receiver operating characteristic (ROC) curve was plotted to determine the diagnostic utility of PIG11 expression in GC. Furthermore, three online databases, including Gene Expression Profiling Interactive Analysis (GEPIA), Oncomine and Kaplan-Meier plotter, were used for bioinformatics analysis of PIG11. PIG11 expression in GC tissues was high, which was positively correlated with invasive depth (P<0.001), lymph node metastasis (P<0.001), distant metastasis (P=0.019), TNM staging (P<0.001) and carcinoembryonic antigen in serum (P<0.001), and negatively associated with the overall survival of patients with GC. The ROC curve analysis suggested that based on PIG11 expression, it was possible to distinguish GC tissues from adjacent normal tissues (P<0.0001) with a sensitivity and specificity of 81.67 and 76.67%, respectively. In addition, Cox logistic regression analysis demonstrated that high PIG11 expression is a novel biomarker for unfavorable prognosis of patients with GC. Furthermore, the results obtained from the GEPIA database indicated that PIG11 expression is correlated with TNF, carcinoembryonic antigen related cell adhesion molecule 5, phosphatidylinositol-4, 5-bisphosphate 3-kinase catalytic subunit alpha, VEGFA and kinase insert domain receptor. Therefore, PIG11 expression may be associated with the malignancy of GC and may serve as a potential diagnostic and prognostic biomarker for GC.

DNA methyltransferase expression is associated with cell proliferation in salivary mucoepidermoid carcinoma

OBJECTIVES

The present study investigated the correlation between the expression of DNA methyltransferase (DNMT)1, DNMT3A, and DNMT3B and the proliferation of mucoepidermoid carcinomas (MECs) using the molecular markers Ki-67 and cyclin D1. This study also demonstrates the effects of 5-aza-2-deoxycytidine (5AC) on the MEC tumor cell lines in relation to DNMT1 and DNMT3A expression, and cell-cycle arrest.

MATERIALS AND METHODS

The immunohistochemistry of DNMT1, DNMT3A, DNMT3B, Ki-67, and cyclin D1 was analyzed in 40 samples of MEC and 15 samples of healthy minor salivary glands. The effects of 5AC on DNMT1 and DNMT3B expression in MEC cell lines were analyzed by Western blot, and the effects of 5AC on the cell cycle were analyzed using flow cytometry.

RESULTS

The expression of DNMT1 and DNMT3B was more intense in MECs than in healthy salivary glands. A strong correlation was found between the expression of the DNMTs and the proliferation markers. This correlation was validated In Vitro, where treatment with 5AC reduced the expression of the DNMTs and the percentage of cells at the G2/M phase of the cell cycle.

CONCLUSION

The expression of DNMT1, DNMT3A, DNMT3B is correlated significantly with the expression of Ki-67 and cyclin D1. The treatment with 5AC reduces DNMT expression and decreases the percentage of cells at the G2/M phase of the cell cycle, while increasing the cells at the G0/G1 phase.

XPO1 inhibition by selinexor induces potent cytotoxicity against high grade bladder malignancies

Treatment options for high grade urothelial cancers are limited and have remained largely unchanged for several decades. Selinexor (KPT-330), a first in class small molecule that inhibits the nuclear export protein XPO1, has shown efficacy as a single agent treatment for numerous different malignancies, but its efficacy in limiting bladder malignancies has not been tested. In this study we assessed selinexor-dependent cytotoxicity in several bladder tumor cells and report that selinexor effectively reduced XPO1 expression and limited cell viability in a dose dependent manner. The decrease in cell viability was due to an induction of apoptosis and cell cycle arrest. These results were recapitulated in in vivo studies where selinexor decreased tumor growth. Tumors treated with selinexor expressed lower levels of XPO1, cyclin A, cyclin B, and CDK2 and increased levels of RB and CDK inhibitor p27, a result that is consistent with growth arrest. Cells expressing wildtype RB, a potent tumor suppressor that promotes growth arrest and apoptosis, were most susceptible to selinexor. Cell fractionation and immunofluorescence studies showed that selinexor treatment increased nuclear RB levels and mechanistic studies revealed that RB ablation curtailed the response to the drug. Conversely, limiting CDK4/6 dependent RB phosphorylation by palbociclib was additive with selinexor in reducing bladder tumor cell viability, confirming that RB activity has a role in the response to XPO1 inhibition. These results provide a rationale for XPO1 inhibition as a novel strategy for the treatment of bladder malignancies.