Expression and clinical significance of hepaCAM and VEGF in urothelial carcinoma

Panobinostat reverses HepaCAM gene expression and suppresses proliferation by increasing histone acetylation in prostate cancer

Increased expression of histone deacetylases (HDACs) affiliated to the epigenetic regulation is common aberration in prostate cancer (PCa). We have confirmed that hepatocyte cell adhesion molecule (hepaCAM), acting as a tumor suppressor gene, is rarely expressed in PCa previously, However, the mechanisms of which is still unknown. The level of histone acetylation reportedly may involve anti-oncogene transcription and expression. In this study, we investigated the effect of panobinostat, the broad-spectrum histone deacetylases inhibitor, on PCa LNCaP and DU145 cell growth, and observed re-expression of hepaCAM when treated with panobinostat. We demonstrated that intranuclear acetylation of lys9 of histone H3 (Ac-H3K9) were increased, while that of both mRNA and protein of HDAC1, HDAC3, and HDAC4 were decreased when the treating concentration of panobinostat increased. We confirmed the relationship between histone acetylation and the expression of hepaCAM and AR in prostate cancer tissues. We also confirmed that panobinostat could overcome the resistance for androgen deprivation therapy (ADT). Further, we combined panobinostat with Ad-hepaCAM, which resulted in significantly increased antitumor activity and significant attenuation of the proliferation-associated genes CCND1 and PCNA compared to each single treatment. In conclusion, panobinostat may enhance the acetylation of lys9 of histone 3 and reverse the hepaCAM expression through its inhibitory effect on HDACs activity in PCa LNCaP and DU145 cells; Ad-hepaCAM combined with panobinostat may synergistically inhibit the growth of LNCaP and DU145 cells, via a potential mechanism associated with the down-regulation of the expression of CCND1 and PCNA. These findings suggest that this therapeutic strategy should be further developed in clinical trials.

Association between VEGF gene promoter polymorphisms and bladder cancer: An updated meta-analysis

BACKGROUND

Vascular endothelial growth factor (VEGF) is the key regulator of angiogenesis in the development of various cancers. Previous studies have examined the relationship between VEGF gene promoter polymorphisms such as -2578C/A and -460C/T and bladder cancer risk; however, these results are inconclusive. Therefore, we performed this meta-analysis to investigate the association between VEGF gene promoter polymorphisms and bladder cancer risk.

METHODS

PubMed, Embase, Cochrane Library and Web of Science databases were searched for studies published before September 2018. The methodological quality assessment of included studies was performed based on the Newcastle-Ottawa Quality Scale (NOS). We conducted a systematic review and meta-analysis using both fixed- and random-effect model. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the strength of the relationship. In addition, the stability of our analysis was evaluated by heterogeneity, sensitivity, subgroup of ethnicity, and publication bias analysis.

RESULTS

We finally included 7 case-control studies with a total of 2412 bladder cancer patients and 3157 cancer-free controls. In Asian population with the VEGF -2578C/A polymorphism, significantly higher bladder cancer risks of 1.55 (95% CI = 1.25-1.93) and 1.53 (95% CI = 1.11-2.10) were found in the heterozygous model (AC vs CC) and the dominant model (AA + AC vs CC), respectively. Though there was no statistical association between VEGF -460C/T polymorphism and bladder cancer, a tendency to higher bladder cancer risk was observed in various genetic models (T vs C; TT vs CC; TC vs CC and TT + TC vs CC).

CONCLUSIONS

Our findings suggest that VEGF -2578C/A polymorphism might be a risk factor with a modest significance for bladder cancer only in Asian population. Further studies with a larger sample size and other functional polymorphisms are needed to explore the effects of VEGF gene on the risk of bladder cancer.

A critical review on ramucirumab in the treatment of advanced urothelial cancer

Advanced urothelial cancer (UC) is a lethal disease despite current advances in systemic therapy, including platinum chemotherapy combinations and immune checkpoint inhibition. Tumor angiogenesis is involved in UC growth and metastatic progression. Proangiogenic signaling through the VEGFR is a key process in UC with prognostic significance. Targeting of VEGFR2 with the monoclonal antibody ramucirumab has been tested in various different tumor types. In this review, we discuss the development of the drug in the context of its preclinical and clinical use with a focus on UC. Improvements in our ability to predict responses and resistance are key for maximizing its efficacy and selecting the most appropriate combinations with other active agents.

HEPACAM inhibited the growth and migration of cancer cells in the progression of non-small cell lung cancer

Hepatocyte cell adhesion molecule (HEPACAM), a member of immunoglobulin superfamily, is an adhesion molecule. Although dysregulation of several adhesion molecules has been implicated in the progression of non-small cell lung cancer (NSCLC), the expression profile and functions of HEPACAM in NSCLC remains unknown. In this study, it was found that the expression of HEPACAM was downregulated in NSCLC tissues. Forced expression of HEPACAM in NSCLC cells inhibited the growth and migration of the cancer cells, while knocking down the expression of HEPACAM promoted cell growth, migration, and metastasis. In the molecular mechanism study, HEPACAM was found to be a negative regulator of beta-catenin/TCF signaling. Taken together, this study revealed the suppressive roles of HEPACAM in NSCLC and restoring the function of HEPACAM in NSCLC might be a promising strategy for the therapy.

Multiple mechanisms mediate resistance to sorafenib in urothelial cancer

Genetic and epigenetic changes in the mitogen activated protein kinase (MAPK) signaling render urothelial cancer a potential target for tyrosine kinase inhibitor (TKI) treatment. However, clinical trials of several TKIs failed to prove efficacy. In this context, we investigated changes in MAPK signaling activity, downstream apoptotic regulators and changes in cell cycle distribution in different urothelial cancer cell lines (UCCs) upon treatment with the multikinase inhibitor sorafenib. None of the classical sorafenib targets (vascular endothelial growth factor receptor 1/-receptor 2, VEGFR1/-R2; platelet-derived growth factor receptor α/-receptor β, PDGFR-α/-β; c-KIT) was expressed at significant levels leaving RAF proteins as its likely molecular target. Low sorafenib concentrations paradoxically increased cell viability, whereas higher concentrations induced G1 arrest and eventually apoptosis. MAPK signaling remained partly active after sorafenib treatment, especially in T24 cells with an oncogenic HRAS mutation. AKT phosphorylation was increased, suggesting compensatory activation of the phosphatidylinositol-3-kinase (PI3K) pathway. Sorafenib regularly down regulated the anti-apoptotic myeloid cell leukemia 1 (Mcl-1) protein, but combinatorial treatment with ABT-737 targeting other B-cell lymphoma 2 (Bcl-2) family proteins did not result in synergistic effects. In summary, efficacy of sorafenib in urothelial cancer cell lines appears hampered by limited effects on MAPK signaling, crosstalk with further cancer pathways and an anti-apoptotic state of UCCs. These observations may account for the lack of efficacy of sorafenib in clinical trials and should be considered more broadly in the development of signaling pathway inhibitors for drug therapy in urothelial carcinoma.

HepaCAM inhibits clear cell renal carcinoma 786-0 cell proliferation via blocking PKCε translocation from cytoplasm to plasma membrane

Hepatocyte cell adhesion molecule (HepaCAM) plays a crucial role in tumor progression and has been recognized as a novel tumor suppressor gene. The high protein expression level of protein kinase Cε (PKCε) has been discovered in many tumor types. In the present study, we determined HepaCAM and PKCε protein levels in human clear cell renal cell carcinoma (ccRCC) tissues and analyzed the correlation between them. We observed an inverse relationship in the expression of HepaCAM and PKCε in ccRCC and adjacent normal tissues. In ccRCC tissue, HepaCAM expression was undetectable while PKCε expression was high; the opposite was found in the adjacent normal tissue. Western blot analysis demonstrated that PKCε cytosolic protein levels increased while plasma membrane protein levels decreased without any change in total protein following infection of the ccRCC cell line 786-0 with adenovirus-GFP-HepaCAM (Ad-GFP-HepaCAM). Moreover, the application of Ad-GFP-HepaCAM combined with a PKCε-specific translocation inhibitor (εV1-2) effectively inhibited 786-0 cell growth. Ad-mediated expression of HepaCAM in 786-0 cells reduced the levels of phosphorylated AKT and cyclin D1 and inhibited cell proliferation. In summary, our studies point to interesting connections between HepaCAM and PKCε in tissues and in vitro. HepaCAM may prevent the translocation of PKCε from cytosolic to particulate fractions, resulting in the inhibition of 786-0 cell proliferation. Therapeutic manipulation of these novel protein targets may provide new ways of treating ccRCC.

Comparing the joint effect of arsenic exposure, cigarette smoking and risk genotypes of vascular endothelial growth factor on upper urinary tract urothelial carcinoma and bladder cancer

Arsenic exposure and cigarette smoking are environmental risk factors for urothelial carcinoma (UC). Vascular endothelial growth factor (VEGF) is the key regulator of angiogenesis in various malignancies. This study investigates the joint effect of arsenic exposure, cigarette smoking, and VEGF polymorphisms on UC risk. This was a hospital-based case-control study consisting of 730 histopathologically confirmed UC cases, including 470 bladder cancers, 260 upper urinary tract UCs (UUTUCs), and 850 age-matched controls, recruited from September 1998 to December 2009. UC risk was estimated by odds ratios and 95% confidence intervals using unconditional logistic regression. Ever smokers with high arsenic exposure had significantly increased risks of 5.7 and 6.4 for bladder cancer and UUTUC, respectively. Moreover, ever smokers with high arsenic exposure carrying 1 or 2 risk genotypes of the VEGF gene had a significantly increased risk of 6.6 for bladder cancer and a strikingly higher risk of 9.9 for UUTUC. Additionally, UUTUC cases with high arsenic exposure carrying 1 or 2 risk genotypes of the VEGF gene had a non-significant increased risk of advanced tumor stage. Our findings suggest that arsenic exposure, cigarette smoking, and risk genotypes of VEGF contribute to a higher risk of UUTUC than of bladder cancer.

Identification of hypermethylation in hepatocyte cell adhesion molecule gene promoter region in bladder carcinoma

BACKGROUND

Epigenetic regulation such as aberrant hypermethylation of CpG islands in promoter plays a key role in tumorigenesis. 5-Aza-2'-deoxycytidine (5-aza-CdR) which is a potent inhibitor of DNA methylation can reverse the abnormal hypermethylation of the silenced tumor suppressor genes (TSGs). It has been reported that hepatocyte cell adhesion molecule (hepaCAM) acts as a tumor suppressor gene and expression of its mRNA and protein were down-regulated in bladder cancer. Over-expression of hepaCAM can inhibit cancer growth and arrest renal cancer cells at G0/G1 phase. In this study, we investigated the methylation status of hepaCAM gene, as well as the influence of 5-aza-CdR on expression of hepaCAM gene in bladder cancer cells.

METHODS

CpG islands in hepaCAM promoter and methprimers were predicted and designed using bioinformatics program. Methylation status of hepaCAM promoter was evaluated in bladder cancer tissues and two cell lines (T24 and BIU-87) by Methylation-specific PCR; Western blot and Immunofluorescence were used to detect expression of hepaCAM protein after 5-aza-CdR treatment; Flow cytometry assay was performed to determine effectiveness of 5-aza-CdR on cell cycle profile.

RESULTS

CpG island in promoter of hepaCAM gene was hyper-methylated both in bladder carcinoma tissues and cell lines (T24 and BIU-87). Otherwise, aberrant methylation of its promoter was associated with its decreased expression. Hypermethylation of hepaCAM gene was reversed and expression of its mRNA and protein were re-activated in two cell lines by DNA methyltransferases inhibitor 5-aza-CdR. Flow cytometry assay demonstrated that 5-aza-CdR can inhibit growth of cancer cells by arresting cancer cells at G0/G1 phase.

CONCLUSION

Abnormal hypermethylation in CpG island of hepaCAM promoter is involved in absence of hepaCAM gene expression when bladder cancer occurs. Re-activation of hepaCAM gene by 5-aza-CdR can inhibit growth of cancer cells and arrest cells at G0/G1 phase.

The 786-0 renal cancer cell-derived exosomes promote angiogenesis by downregulating the expression of hepatocyte cell adhesion molecule

The aims of the current study were to determine whether 786‑0 renal cancer cell‑derived exosomes promote human umbilical vein endothelial cells (HUVECs) to form tubular structures and to uncover the underlying mechanisms associated with this process. Exosomes were extracted and purified using ultrafiltration and sucrose gradient centrifugation and characterized by transmission electron microscopy. Tubular structure formation was observed using the matrigel tubular assay. In addition, an adenovirus vector was used to transfect the hepatocyte cell adhesion molecule (hepaCAM) gene into renal cancer 786‑0 cells. The expression of hepaCAM and vascular endothelial growth factor (VEGF) mRNA and protein was determined by reverse transcription‑polymerase chain reaction and western blot analysis, respectively. Tumor cell‑derived exosomes were observed to significantly increase tubular formation in HUVECs. Following transfection with the hepaCAM gene, VEGF expression in 786‑0 cells was markedly decreased. In HUVECs, exosome treatment increased VEGF mRNA and protein expression, while hepaCAM expression was only decreased at the protein level. In the present study, renal cancer 786‑0 cell‑derived exosomes significantly promoted angiogenesis via upregulation of VEGF expression in HUVECs, which may be induced by the downregulation of hepaCAM.

VEGF induces sensory and motor peripheral plasticity, alters bladder function, and promotes visceral sensitivity

BACKGROUND

This work tests the hypothesis that bladder instillation with vascular endothelial growth factor (VEGF) modulates sensory and motor nerve plasticity, and, consequently, bladder function and visceral sensitivity.In addition to C57BL/6J, ChAT-cre mice were used for visualization of bladder cholinergic nerves. The direct effect of VEGF on the density of sensory nerves expressing the transient receptor potential vanilloid subfamily 1 (TRPV1) and cholinergic nerves (ChAT) was studied one week after one or two intravesical instillations of the growth factor.To study the effects of VEGF on bladder function, mice were intravesically instilled with VEGF and urodynamic evaluation was assessed. VEGF-induced alteration in bladder dorsal root ganglion (DRG) neurons was performed on retrogradly labeled urinary bladder afferents by patch-clamp recording of voltage gated Na+ currents. Determination of VEGF-induced changes in sensitivity to abdominal mechanostimulation was performed by application of von Frey filaments.

RESULTS

In addition to an overwhelming increase in TRPV1 immunoreactivity, VEGF instillation resulted in an increase in ChAT-directed expression of a fluorescent protein in several layers of the urinary bladder. Intravesical VEGF caused a profound change in the function of the urinary bladder: acute VEGF (1 week post VEGF treatment) reduced micturition pressure and longer treatment (2 weeks post-VEGF instillation) caused a substantial reduction in inter-micturition interval. In addition, intravesical VEGF resulted in an up-regulation of voltage gated Na(+) channels (VGSC) in bladder DRG neurons and enhanced abdominal sensitivity to mechanical stimulation.

CONCLUSIONS

For the first time, evidence is presented indicating that VEGF instillation into the mouse bladder promotes a significant increase in peripheral nerve density together with alterations in bladder function and visceral sensitivity. The VEGF pathway is being proposed as a key modulator of neural plasticity in the pelvis and enhanced VEGF content may be associated with visceral hyperalgesia, abdominal discomfort, and/or pelvic pain.

Role of the angiogenic components, VEGFA, FGF2, OPN and RHOC, in urothelial cell carcinoma of the urinary bladder

The objective of this study was to analyze the expression profile of the angiogenic components, vascular endothelial growth factor-A (VEGFA), basic fibroblast growth factor-2 (FGF2), osteopontin (OPN) and ras homolog gene family, member C (RHOC), in urothelial cell carcinoma (UCC) of the urinary bladder and to examine their role as candidate diagnostic biomarkers. Using qPCR, 77 samples of UCC of the urinary bladder and 77 matched tumor-associated normal samples were investigated to determine the expression of the four angiogenic components. The correlation between gene expression, patient survival and pathological features of the tumors was also examined. The VEGFA and OPN transcript levels were greater in the bladder cancer tissue than in the normal urothelium (P<0.001). Patients with higher VEGFA mRNA levels showed a tendency towards shorter cancer-specific survival. OPN levels showed a gradual increase, the lowest levels being found in non-invasive carcinoma and the highest in muscle invasive tumors. Elevated OPN levels indicated poor prognosis in connection with advanced disease stage (P<0.001). Both superficially invasive and muscle invasive tumors had significantly higher FGF2 levels compared to the control tissues (P=0.018 and P=0.050, respectively). Moreover, FGF2 was significantly higher in the metastatic vs. the non-metastatic tumors (P=0.0097). FGF2 levels exhibited a trend towards a correlation with worse patient survival. RHOC mRNA levels were higher in muscle invasive compared to superficially invasive tumors, as well as in grade III vs. grade I/II tumors. Furthermore, we detected worse overall survival for patients with high RHOC expression levels. VEGFA and FGF2 exhibited the best linear combination in the ROC curves for specificity and sensitivity. Thus, VEGFA and FGF2 may serve as candidate biomarkers for diagnostic purposes. Higher OPN expression may be used as a potential biomarker to predict patient survival relative to advanced tumor stage. However, further studies are required to investigate its role in urinary bladder carcinogenesis.

HepaCAM induces G1 phase arrest and promotes c-Myc degradation in human renal cell carcinoma

Hepatocyte cell adhesion molecule (hepaCAM) encodes a generally inactive phosphorylated glycoprotein which mediates cancer cell proliferation, migration, and differentiation. We have reported that hepaCAM is down-regulated in renal cell carcinoma (RCC) and takes responsibility of cell growth inhibition. However, the precise mechanisms of hepaCAM inhibits cell growth is still unknown. In this study, we demonstrated that re-expression of hepaCAM can cause an accumulation in G0/G1 phase in 786-0 cells. This reaction was accompanied by a substantial reduction of c-Myc expression through using an ectopic hepaCAM expression system. Furthermore, we found a comparable decrease in proliferation and G0/G1 accumulation of 786-0 and RC-2 cells after treatment with a small molecule c-Myc inhibitor, 10058-F4. This indicated that the down regulation of c-Myc was an essential process in controlling growth inhibitory actions of hepaCAM. Nevertheless, re-expression of hepaCAM results in apparent reduction of c-Myc protein with no corresponding reduction of c-Myc mRNA. This suggests that this reaction might take place at a post-transcriptional level rather than transcriptional one. Consistent with these findings, hepaCAM decreased c-Myc stability by increasing the proportion of c-Myc phosphorylation on T58 which can be abrogated by a proteasomal inhibitor (MG132). Thus, our research implies that the decrease in c-Myc protein expression, resulting from ectopic expression of hepaCAM, may contribute to the inhibition of proliferation in these cells.