Screening and identification of specific markers for bladder transitional cell carcinoma from urine urothelial cells with suppressive subtractive hybridization and cDNA microarray

Homeobox Gene Expression Dysregulation as Potential Diagnostic and Prognostic Biomarkers in Bladder Cancer

Homeobox genes serve as master regulatory transcription factors that regulate gene expression during embryogenesis. A homeobox gene may have either tumor-promoting or tumor-suppressive properties depending on the specific organ or cell lineage where it is expressed. The dysregulation of homeobox genes has been reported in various human cancers, including bladder cancer. The dysregulated expression of homeobox genes has been associated with bladder cancer clinical outcomes. Although bladder cancer has high risk of tumor recurrence and progression, it is highly challenging for clinicians to accurately predict the risk of tumor recurrence and progression at the initial point of diagnosis. Cystoscopy is the routine surveillance method used to detect tumor recurrence. However, the procedure causes significant discomfort and pain that results in poor surveillance follow-up amongst patients. Therefore, the development of reliable non-invasive biomarkers for the early detection and monitoring of bladder cancer is crucial. This review provides a comprehensive overview of the diagnostic and prognostic potential of homeobox gene expression dysregulation in bladder cancer.

Differential Protein Expression Patterns of HOXA13 and HOXB13 Are Associated with Bladder Cancer Progression

Bladder cancer is a common urological cancer and has the highest recurrence rate of any cancer. The aim of our study was to profile and characterize the protein expression of homeobox A13 (HOXA13) and homeobox B13 (HOXB13) genes in Malaysian bladder cancer patients. The protein expression of HOXA13 and HOXB13 in formalin-fixed paraffin-embedded (FFPE) bladder cancer tissues was determined by immunohistochemistry (IHC) analysis. The association between HOXA13/HOXB13 protein expression and demographic/clinicopathological characteristics of the bladder cancer patients was determined by chi-square analysis. Approximately 63.6% of the bladder cancer tissues harbored high HOXA13 expression. High HOXA13 expression was significantly associated with non-muscle invasive bladder cancer, lower tumor grade, higher number of lymph node metastases, and recurrence risk. In contrast, low HOXB13 expression (including those with negative expression) was observed in 71.6% of the bladder cancer tissues analyzed. Low HOXB13 expression was significantly associated with muscle-invasive bladder cancer, higher tumor stage, tumor grade, and metastatic risk. Both HOXA13 and HOXB13 protein expression were found to be associated with bladder tumorigenesis. The putative oncogenic and tumor suppressive roles of HOXA13 and HOXB13, respectively, suggest their potential utility as biomarkers in bladder cancer.

Paralogous HOX13 Genes in Human Cancers

Hox genes (HOX in humans), an evolutionary preserved gene family, are key determinants of embryonic development and cell memory gene program. Hox genes are organized in four clusters on four chromosomal loci aligned in 13 paralogous groups based on sequence homology (Hox gene network). During development Hox genes are transcribed, according to the rule of “spatio-temporal collinearity”, with early regulators of anterior body regions located at the 3’ end of each Hox cluster and the later regulators of posterior body regions placed at the distal 5’ end. The onset of 3’ Hox gene activation is determined by Wingless-type MMTV integration site family (Wnt) signaling, whereas 5’ Hox activation is due to paralogous group 13 genes, which act as posterior-inhibitors of more anterior Hox proteins (posterior prevalence). Deregulation of HOX genes is associated with developmental abnormalities and different human diseases. Paralogous HOX13 genes (HOX A13, HOX B13, HOX C13 and HOX D13) also play a relevant role in tumor development and progression. In this review, we will discuss the role of paralogous HOX13 genes regarding their regulatory mechanisms during carcinogenesis and tumor progression and their use as biomarkers for cancer diagnosis and treatment.

Bladder Cancer-Specific Nuclear Matrix Proteins-4 May Be a Potential Biomarker for Non-Muscle-Invasive Bladder Cancer Detection

Aims

Bladder cancer–specific nuclear matrix protein-4 (BLCA-4) is a protein expressed mainly in bladder cancer tissues. Therefore, the aim of this study was to investigate its assisting diagnostic potential in non-muscle-invasive bladder cancer (NMIBC).

Methods

Twenty patients with NMIBC, 20 with benign prostatic hyperplasia (BPH), and 20 normal controls were included in this study. Blood and urine samples were collected from all patients. Moreover, cancer foci and adjacent tissue samples were collected from NMIBC patients, and normal bladder tissue samples were collected from patients with BPH. A competitive enzyme-linked immunosorbent assay was used to determine the BLCA-4 level in serum and urine, and immunohistochemistry was used to examine BLCA-4 expression in bladder cancer, adjacent, and normal tissues.

Results

Median urinary BLCA-4 levels in the NMIBC, BPH, and normal control groups were 0.759 ng/mL, 0.309 ng/mL, and 0.171 ng/mL, respectively. Urinary BLCA-4 level was significantly higher in the NMIBC group than in the other 2 groups (P < 0.01); meanwhile, the BPH group was higher than the normal control group (P < 0.05). Median serum BLCA-4 levels in the NMIBC, BPH, and normal control groups were 5.680 ng/mL, 5.928 ng/mL, and 5.473 ng/mL, respectively, showing no significant difference among groups (P > 0.05).

Conclusion

As a new marker of bladder cancer, urinary BLCA-4 level detection might apply for clinical diagnosis or postoperative monitoring for NMIBC.

An update on the molecular pathology of urinary bladder tumors

Urothelial carcinoma is the fourth most common tumors after prostate cancer, lung, and colorectal carcinoma but the second most common urologic malignancy. Urothelial carcinoma composed more than 90% of bladder tumors while squamous cell carcinoma and adenocarcinomas composed 5% and 2% respectively. The intense research involving the different molecular aspects of bladder cancer has provided a great insight into identifying more about molecular profiling and pathways of bladder cancer. In this review, we will highlight the general concepts of the molecular features; profiling and classification as well as the molecular pathways for bladder carcinomas, especially urothelial carcinoma. Also, we will discuss the advances of molecular biomarkers for screening, early diagnosis, surveillance and potential prognosis of urothelial carcinoma of the bladder. Studies showed that accumulation of genetic alterations involving the clonal expansion of altered cells with growth advantages through sequential multi-step pathways results in progression of bladder tumors. The accumulated research data from literature has revealed that the genomic signatures of urothelial carcinoma are required to subclassify bladder cancer into genetically distinct subgroups. These findings could improve the understating of pathogenesis as well as will provide new therapeutic modules e.g. targeted therapy.

Dysregulated expression of homebox gene HOXA13 is correlated with the poor prognosis in bladder cancer

BACKGROUND

The homeobox (HOX) genes have been implicated playing important roles in many human cancers. HOXA13 is a member of HOX genes that encode transcription factors regulating embryonic development and cell fate. In the present study, we aimed to investigate the expression and prognostic significance of HOXA13 in bladder cancer.

METHODS

Immunohistochemical staining was initially performed to screen the differentially expressed HOXA13 between bladder cancer tissues and paired adjacent non-cancerous tissues. Subsequent Western blotting analysis validation was conducted using tissue samples from patients with bladder cancer.

RESULTS

The expression level of HOXA13 was significantly higher in bladder cancer tissues compared to that in adjacent non-cancerous tissues (P < 0.001). The χ²-test showed that expression of HOXA13 was positively correlated with lymphatic metastasis (P = 0.013), bladder tumor TNM stage (P = 0.002) and pathological grade (P < 0.001). Kaplan-Meier survival analysis revealed that patients with bladder cancer with high expression of HOXA13 had shorter overall survival time (P = 0.001) and disease-free survival time (P = 0.001) compared to patients with low expression of HOXA13. Multivariate analysis indicated that HOXA13 was an independent prognostic factor for overall survival for bladder cancer patients.

CONCLUSIONS

The results of our study show that high expression of HOXA13 is associated with the progression of bladder cancer and that HOXA13 might serve as a biomarker for prognosis of bladder cancer.

Urine BLCA-4 exerts potential role in detecting patients with bladder cancers: a pooled analysis of individual studies

Epidemiological studies have explored the diagnostic effect of urine BLCA-4 in bladder cancer. However, the results remain controversial. Therefore, we conducted this pooled analyses to determine the overall accuracy of urine BLCA-4 in bladder cancer. A comprehensive electronic and hand search was conducted for related literatures though several databases. QUADAS-2 was used to assess the quality of each included studies. Diagnostic parameters were calculated using Meta-Disc (version 1.4) and Stata (version 12.0) software. Nine published articles with 1,119 subjects were included. The summary estimates were: sensitivity 0.93 (95% confidence interval [CI] = 0.90-0.95), specificity 0.97 (95% CI, 0.95-0.98), positive likelihood ratio 48.16 (95% CI, 11.77-197.01), negative likelihood ratio 0.08 (95% CI, 0.06-0.11), diagnostic odds ratio 534.03 (95% CI, 150.15-1899.31), and the AUC was 0.9607. In conclusion, urine BLCA-4 is a promising marker in diagnosing bladder cancer.

Up-regulation of long non-coding HOTTIP functions as an oncogene by regulating HOXA13 in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the major cause of cancer death worldwide. Increasing evidences show that long non coding RNAs (lncRNAs) are widely involved in the development and progression of NSCLC. The lncRNA HOTTIP has been identified as an oncogene in several human cancers, but its role in NSCLC remains unknown. The present study was to determine the expression and function of HOTTIP in NSCLC. Quantitative real-time PCR was used to detect the expressions of HOTTIP in 53 paired NSCLC tissues and cell lines. Furthermore, RNA interference (RNAi) and over-expression approaches were used to investigate the biological function of HOTTIP in lung cancer cell line. The impacts of HOTTIP on cell migration, proliferation and apoptosis were analyzed using wound scratch assay, MTT and flow cytometry, respectively. The results revealed that the HOTTIP expression was significantly up-regulated in NSCLC tissues and cells when compared with corresponding adjacent normal tissues and normal bronchial epithelial cells (p<0.05). Furthermore, knock-down of HOTTIP significantly inhibited cell proliferation, migration and induced cell apoptosis in vitro, while over-expression of HOTTIP led to the opposite effects. In addition, we identified HOTTIP as a transcriptional regulator of HOXA13 in lung cancer cell. Ectopic expression of HOTTIP suppressed the endogenous level of HOXA13, while knock-down of HOTTIP increased HOXA13 expression. Knock-down of HOXA13 by RNA interference (siHOXA13) revealed that HOTTIP promoted lung cell proliferation, migration, and inhibited apoptosis, at least partly by regulating HOXA13. The present study is the first to identify that HOTTIP functions as an oncogene by regulating HOXA13 in NSCLC, which may represent a new biomarker and a potential therapeutic target for NSCLC intervention.

The long non-coding RNA HOTTIP promotes progression and gemcitabine resistance by regulating HOXA13 in pancreatic cancer

Background

The human genome encodes many long non-coding RNAs (lncRNAs). However, their biological functions, molecular mechanisms, and the prognostic value associated with pancreatic ductal adenocarcinoma (PDAC) remain to be elucidated. Here, we identify a fundamental role for the lncRNA HOXA transcript at the distal tip (HOTTIP) in the progression and chemoresistance of PDAC.

Methods

High-throughput microarrays were performed to detect the expression profiles of lncRNAs and messenger RNAs in eight human PDAC tissues and four pancreatic tissues. Quantitative real-time PCR was used to determine the levels of HOTTIP and HOXA13 transcripts in PDAC cell lines and 90 PDAC samples from patients. HPDE6 cells (immortalized human pancreatic ductal epithelial cells) and corresponding adjacent non-neoplastic tissues were used as controls, respectively. The functions of HOTTIP and HOXA13 in cell proliferation, invasion, and epithelial-mesenchymal transition were evaluated by targeted knockdown in vitro. CCK-8 assays, colony formation assays, and xenografts in nude mice were used to investigate whether targeted silencing of HOTTIP could sensitize pancreatic cancer cells to gemcitabine. Immunohistochemistry was performed to investigate the relationship between HOXA13 expression and patient outcome.

Results

Microarray analyses revealed that HOTTIP was one of the most significantly upregulated lncRNAs in PDAC tissues compared with pancreatic tissues. Quantitative PCR further verified that HOTTIP levels were increased in PDAC cell lines and patient samples compared with controls. Functionally, HOTTIP silencing resulted in proliferation arrest by altering cell-cycle progression, and impaired cell invasion by inhibiting epithelial-mesenchymal transition in pancreatic cancer. Additionally, inhibition of HOTTIP potentiated the antitumor effects of gemcitabine in vitro and in vivo. Furthermore, knockdown of HOXA13 by RNA interference (siHOXA13) revealed that HOTTIP promoted PDAC cell proliferation, invasion, and chemoresistance, at least partly through regulating HOXA13. Immunohistochemistry results revealed that higher HOXA13 expression was correlated with lymph node metastasis, poor histological differentiation, and decreased overall survival in PDAC patients.

Conclusions

As a crucial tumor promoter, HOTTIP promotes cell proliferation, invasion, and chemoresistance by modulating HOXA13. Therefore, the HOTTIP/HOXA13 axis is a potential therapeutic target and molecular biomarker for PDAC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-015-0442-z) contains supplementary material, which is available to authorized users.