Transforming growth factor-beta type II receptor confers tumor suppressor activity in murine renal carcinoma (Renca) cells

Histone deacetylase inhibitors dysregulate DNA repair proteins and antagonize metastasis-associated processes

Purpose

We set out to determine whether clinically tested epigenetic drugs against class I histone deacetylases (HDACs) affect hallmarks of the metastatic process.

Methods

We treated permanent and primary renal, lung, and breast cancer cells with the class I histone deacetylase inhibitors (HDACi) entinostat (MS-275) and valproic acid (VPA), the replicative stress inducer hydroxyurea (HU), the DNA-damaging agent cis-platinum (L-OHP), and the cytokine transforming growth factor-β (TGFβ). We used proteomics, quantitative PCR, immunoblot, single cell DNA damage assays, and flow cytometry to analyze cell fate after drug exposure.

Results

We show that HDACi interfere with DNA repair protein expression and trigger DNA damage and apoptosis alone and in combination with established chemotherapeutics. Furthermore, HDACi disrupt the balance of cell adhesion protein expression and abrogate TGFβ-induced cellular plasticity of transformed cells.

Conclusion

HDACi suppress the epithelial–mesenchymal transition (EMT) and compromise the DNA integrity of cancer cells. These data encourage further testing of HDACi against tumor cells.

Electronic supplementary material

The online version of this article (10.1007/s00432-019-03118-4) contains supplementary material, which is available to authorized users.

Cadmium and Lead Decrease Cell-Cell Aggregation and Increase Migration and Invasion in Renca Mouse Renal Cell Carcinoma Cells

Metastatic renal cell carcinoma (RCC) remains an important clinical issue; the 5-year survival rate of patients with metastasis is approximately 12%, while it is 93% in those with localized disease. There is evidence that blood cadmium and lead levels are elevated in RCC. The current studies were designed to assess the impact of cadmium and lead on the progression of RCC. The disruption of homotypic cell-cell adhesion is an essential step in epithelial-to-mesenchymal transition and tumor metastasis. Therefore, we examined the impact of cadmium and lead on the cadherin/catenin complex in Renca cells-a mouse RCC cell line. Lead, but not cadmium, induced a concentration-dependent loss of E-cadherin, while cadmium, but not lead, increased p120-catenin expression, specifically isoform 1 expression. Lead also induced a substantial increase in matrix metalloproteinase-9 levels. Both cadmium and lead significantly decreased the number of Renca cell aggregates, consistent with the disruption of the cadherin/catenin complex. Both metals enhanced wound healing in a scratch assay, and increased cell migration and invasion. These data suggest that cadmium and lead promote RCC progression.

Reduction of transforming growth factor-beta type II receptor is caused by the enhanced ubiquitin-dependent degradation in human renal cell carcinoma

Although dysregulation of transforming growth factor-beta (TGF-beta) signaling is implicated in renal carcinogenesis, its precise mechanism is unknown in renal cell carcinoma (RCC). In our study, we investigated Smad-mediated TGF-beta signaling pathway and its regulatory mechanisms in surgical samples from patients with RCC. We found that immunoreactivity for nuclear phosphorylated Smad2 was significantly decreased in RCC compared to normal renal tissues, thereby TGF-beta signaling was suggested to be attenuated in RCC tissues. In accordance with the result, transcriptional downregulation of Smad4 and post-transcriptional downregulation of TGF-beta type II receptor (TbetaR-II) were frequently found in RCC tissues compared to normal renal tissues. Next, to clarify the reason why the protein level of TbetaR-II was decreased in RCC, we investigated the activities of degradation and ubiquitination of TbetaR-II. We found that both proteasome-mediated degradation and ubiquitination of TbetaR-II were markedly enhanced in RCC tissues. Moreover, we found that the level of Smad-ubiquitination regulatory factor 2 (Smurf2), the E3 ligase for TbetaR-II, was increased in RCC tissues of the patients with higher clinical stages compared to the normal tissues and was inversely correlated with the level of TbetaR-II. Our results suggest that the low TbetaR-II protein level is due to augmented ubiquitin-dependent degradation via Smurf2 and might be involved in the attenuation of TGF-beta signaling pathway in RCC.

Treatment of transforming growth factor-beta-insensitive mouse Renca tumor by transforming growth factor-beta elimination

OBJECTIVES

The mouse renal cell carcinoma line, Renca, is insensitive to transforming growth factor-beta (TGF-beta) in vitro. The present study was conducted to determine whether removal of TGF-beta from these tumor cells would inhibit tumor progression in vivo.

METHODS

TGF-beta elimination was accomplished either by administration of neutralizing TGF-beta antibody into mice receiving intravenous injection of Renca tumor cells or infection of TGF-beta antisense expression vector into these tumor cells before subcutaneous injection into recipient mice.

RESULTS

Although a low dose of TGF-beta antibody (5 mg/kg every 3 days) was without any effect, a high dose of TGF-beta antibody (50 mg/kg every 3 days), administered to recipient mice, resulted in a significant reduction in lung metastasis and was accompanied by increased apoptosis in the tumor cells. When the tumor cells were transfected with a TGF-beta1 antisense expressing vector, a significant reduction occurred in the tumor incidence, as well as the tumor burden. However, in nude mice, cells with reduced TGF-beta1 production grew almost as well as did the unmodified Renca cells, suggesting that the host's immune system might play an antitumor role.

CONCLUSIONS

These results indicate that progression of Renca tumor can be inhibited by eliminating TGF-beta from the tumor cells. Our results also suggest that, although insensitive to TGF-beta under in vitro conditions, Renca tumors could be inhibited by TGF-beta removal through the systemic host environment.

Targeted therapy for renal cell carcinoma: a new therapeutic paradigm

Renal cell carcinoma is the most common tumor of the kidney. It has an unpredictable behavior and poor response to systemic therapy. Developing newer therapy for this disease is a priority considering the high recurrence rate and the small subset of patients who benefit from the use of cytokines such as interferon-alpha or interleukin-2. Identifying molecular targets and targeting various biomarkers has revolutionized the therapeutic approach to advanced and metastatic renal cell carcinoma. Although some of the antiangiogenic agents and receptor tyrosine kinase inhibitors appear promising, further understanding of their mechanism of action and the patient population who would benefit most from such agents is still being explored. As numerous targeted agents are entering the clinical investigation arena in a relatively short period of time, newer challenges in renal cell carcinoma therapeutics are emerging. Some of the future challenges in using targeted antineoplastic agents in renal cell carcinoma will include evaluating their long-term safety and benefit, using the particular drug in the appropriate patient population after appropriate stratification and studying the combination of some of these drugs for synergy or additive effects.

Molecular pathogenetics of renal cancer

Recent developments in genetics and molecular biology have led to an increased understanding of the pathobiology of renal cancer. Thorough knowledge of the molecular pathways associated with renal cancer is a prerequisite for novel potential therapeutic interventions. Studies are ongoing to evaluate novel anticancer agents that target specific molecular entities. This article reviews current knowledge on the genetics and molecular pathogenesis of sporadic and inherited forms of renal cancer.

Elucidation of the molecular signatures of renal cell carcinoma by gene expression profiling

Renal cell carcinoma (RCC) is the 10th most common cancer in United States. It is a heterogeneous disease with various histologic types. Since high-throughput technologies such as microarrays have been introduced, molecular confirmation of previously known findings in RCC has been made and new molecular findings have emerged. We review the accumulating advances in this field and their clinical implications. The published data so far have proved to be significant and promising, and numerous microarray studies with larger number of cases are currently ongoing or being planned. Although various clinical parameters are being refined for diagnosis and prognosis, these data obtained by microarray studies will undoubtedly contribute to both and eventually impacts the treatment of RCC.

Restoration of expression of transforming growth factor-beta type II receptor in murine renal cell carcinoma (renca) cells by 5-Aza-2'-deoxycytidine

The murine renal cell carcinoma (Renca) cells are insensitive to TGF-beta due to a lack of TGF-beta type II receptor (TbetaR-II). The objective of the present study is to determine the mechanism of this loss of sensitivity to TGF-beta in Renca cells. Renca cells were cultured and treated with 5-Aza-2'-Deoxycytidine (5-Aza), a specific inhibitor of methylation. Expression of TGF-beta type I receptor (TbetaRI) and TbetaRII was determined by RT-PCR and Western blot analysis before and after the treatment of Renca cells with 5-Aza. The expression of phosphorylated Smad2 (P-Smad2) was determined by Western blot analysis. TGF-beta levels in the conditioned medium were measured by ELISA. Renca cells did not express TbetaR-II prior to 5-Aza treatment. After 5-Aza treatment, these cells expressed TbetaR-II at both mRNA and protein levels, which corresponded to the restoration of sensitivity to TGF-beta by an increase in P-Smad2. Levels of TGF-beta1 were similar before and after 5-Aza treatment. Results of the present study indicated that, in Renca cells, the loss of sensitivity to TGF-beta is likely due to a promoter hypermethylation in the TbetaR-II gene.

Proteomics in the postgenomic age

Technical developments in the field of proteomics are poised to generate advances in our understanding of protein structure, function, and organization in complex signaling and regulatory networks. Improvements in mass spectrometry instrumentation, the implementation of protein arrays, and the development of robust informatics software are providing sensitive, high-throughput technologies for large-scale identification and quantitation of protein expression, protein modifications, subcellular localization, protein function, and protein-protein interactions. These advances have significant implications for understanding how cellular proteomes are regulated in health and disease.

Genomic profiling identifies alterations in TGFbeta signaling through loss of TGFbeta receptor expression in human renal cell carcinogenesis and progression

Renal cell carcinoma (RCC) is a major health issue. Whereas localized disease can be cured surgically, there is no effective therapy for metastatic disease. The development of an effective therapy will require an understanding of the pathways that are important in RCC carcinogenesis and progression. Using genomic profiling of patient-matched tissue, we have identified aberrations in the transforming growth factor beta (TGFbeta) signaling pathway in RCC. We observed loss of type III TGFbeta receptor (TBR3) expression in all RCC samples. This suggests that TBR3 loss is an early event in RCC carcinogenesis and plays a sentinel role in the acquisition of a tumorigenic phenotype. We also observed subsequent loss of type II TGFbeta receptor (TBR2) expression in metastatic RCCs. We propose that loss of TBR3 is necessary for RCC carcinogenesis, and that loss of TBR2 leads to acquisition of a metastatic phenotype. To this end, we have identified a human renal cell carcinoma line (UMRC6) that is representative of localized, nonmetastatic RCC, reflecting a loss of TBR3, but not TBR2 expression. Another cell line, UMRC3, is highly metastatic, having lost TBR3 and TBR2 expression. We demonstrate functional loss of TGFbeta responsiveness in these cell lines as observed through phenotypic and transcriptional responsiveness to exogenous TGFbeta. Restoring TBR2 and TBR3 expression in UMRC3 cells attenuates cell proliferation, completely restores TGFbeta-mediated transcriptional responses, and completely blocks anchorage independent-growth: while restoration of TBR2 partially restores TGFbeta-mediated signaling. Based on these data, we propose that dysregulation in TGFbeta signaling, through stepwise loss in receptor expression, plays a prominent role in RCC carcinogenesis and progression. In addition, these studies unequivocably demonstrate a link between loss of TBR3 and a human disease.

Loss of expression of transforming growth factor-beta receptor as a prognostic factor in patients with renal cell carcinoma

OBJECTIVES

To determine the clinical implication of the loss of transforming growth factor-beta (TGF-beta) receptor (TbetaR) expression for the pathologic features in renal cell carcinoma (RCC) and the prognosis of 62 patients (Stage I, 4; Stage II, 28; Stage III, 11; and Stage IV, 19) who underwent radical nephrectomy for RCC. Loss of expression in TbetaR could result in escape from the growth inhibitory effect of TGF-beta in TGF-beta-secreting cancer.

METHODS

TbetaR and apoptosis in the tumor were detected by immunohistochemistry using samples from 62 patients. We statistically investigated the relationship among the TbetaR expression pattern, pathologic features, and the prognosis of patients with RCC.

RESULTS

A loss of expression of TbetaR-I and TbetaR-II was identified in 29 patients (46.7%) and 31 patients (50.0%), respectively. Although the loss of TbetaR-I was not associated with clinical stage, the loss of TbetaR-II was associated with clinical stage (P <0.01). Univariate analysis of all patients demonstrated that Stage T3 or greater, clinical Stage III or greater, loss of TbetaR-II, and a tumor apoptotic index of less than 35 were associated with a significantly lower survival rate than their respective counterparts. Multivariate analysis showed that the only two significant prognostic factors were clinical stage and loss of TbetaR-II. In addition, TbetaR-negative RCC had significantly lower apoptosis than did TbetaR-positive RCC.

CONCLUSIONS

These results suggest that a loss of TbetaR-II expression in the primary tumor is a significant prognostic factor in patients with RCC.

Gene Expression Profiling of Renal Cell Carcinoma and Its Implications in Diagnosis, Prognosis, and Therapeutics

Renal cell carcinoma (RCC) is the 10th most common cancer in the United States. It is a histologically heterogeneous disease with various histologic types being characterized by distinct genetic alterations. This chapter reviews advances in the gene expression profiling of RCC and discusses their clinical implications. Data are promising, and many more RCC-related microarray studies are currently underway or in planning. Undoubtedly these data will have an impact on the diagnosis, prognosis, and treatment of RCCs in the future. Finally, this chapter discusses what additional studies should be performed to help uncover the molecular mechanisms of RCC and to bring this new knowledge into use in the clinical arena.

Gene expression profiling of clear cell renal cell carcinoma: gene identification and prognostic classification

To better understand the molecular mechanisms that underlie the tumorigenesis and progression of clear cell renal cell carcinoma (ccRCC), we studied the gene expression profiles of 29 ccRCC tumors obtained from patients with diverse clinical outcomes by using 21,632 cDNA microarrays. We identified gene expression alterations that were both common to most of the ccRCC studied and unique to clinical subsets. There was a significant distinction in gene expression profile between patients with a relatively nonaggressive form of the disease [100% survival after 5 years with the majority (15/17 or 88%) having no clinical evidence of metastasis] versus patients with a relatively aggressive form of the disease (average survival time 25.4 months with a 0% 5-year survival rate). Approximately 40 genes most accurately make this distinction, some of which have previously been implicated in tumorigenesis and metastasis. To test the robustness and potential clinical usefulness of this molecular distinction, we simulated its use as a prognostic tool in the clinical setting. In 96% of the ccRCC cases tested, the prediction was compatible with the clinical outcome, exceeding the accuracy of prediction by staging. These results suggest that two molecularly distinct forms of ccRCC exist and that the integration of expression profile data with clinical parameters could serve to enhance the diagnosis and prognosis of ccRCC. Moreover, the identified genes provide insight into the molecular mechanisms of aggressive ccRCC and suggest intervention strategies.

Role of transforming growth factor beta in cancer

Transforming growth factor beta (TGF-beta) is an effective and ubiquitous mediator of cell growth. The significance of this cytokine in cancer susceptibility, cancer development and progression has become apparent over the past few years. TGF-beta plays various roles in the process of malignant progression. It is a potent inhibitor of normal stromal, hematopoietic, and epithelial cell growth. However, at some point during cancer development the majority of transformed cells become either partly or completely resistant to TGF-beta growth inhibition. There is growing evidence that in the later stages of cancer development TGF-beta is actively secreted by tumor cells and not merely acts as a bystander but rather contributes to cell growth, invasion, and metastasis and decreases host-tumor immune responses. Subtle alteration of TGF-beta signaling may also contribute to the development of cancer. These various effects are tissue and tumor dependent. Identifying and understanding TGF-beta signaling pathway abnormalities in various malignancies is a promising avenue of study that may yield new modalities to both prevent and treat cancer. The nature, prevalence, and significance of TGF-beta signaling pathway alterations in various forms of human cancer as well as potential preventive and therapeutic interventions are discussed in this review.

Captopril restores transforming growth factor-beta type II receptor and sensitivity to transforming growth factor-beta in murine renal cell cancer cells

PURPOSE

Captopril is known to inhibit the growth of renal cancer but the mechanism involved has been unclear. The current study elucidates the mechanism of captopril induced inhibition of the growth of the Renca mouse renal cancer cell line involving transforming growth factor-beta, which is known to be a growth inhibitory cytokine in epithelial cells and tissues.

MATERIALS AND METHODS

Transforming growth factor-beta in conditioned medium was measured by bioassay. Levels of transforming growth factor-beta and transforming growth factor-beta type II receptor expression messenger RNA were determined by reverse transcriptase-polymerase chain reaction and flow cytometry. Cell viability was determined by bromodeoxyuridine (BrdU) incorporation and tetrazolium bromide assay.

RESULTS

Captopril (0.01 to 1 mM.) showed no significant effect on transforming growth factor-beta synthesis or transforming growth factor-beta messenger RNA in Renca cells. On the other hand, 1 mM. captopril significantly inhibited Renca cell growth. Reverse transcriptase-polymerase chain reaction and flow cytometry showed that 1 mM. captopril up-regulated type II receptor expression.

CONCLUSIONS

These findings suggest that captopril restores transforming growth factor-beta type II receptor expression and inhibits the growth of Renca cells by increasing their sensitivity to transforming growth factor-beta.

Role of transforming growth factor beta in cancer

Transforming growth factor beta (TGF-beta) is an effective and ubiquitous mediator of cell growth. The significance of this cytokine in cancer susceptibility, cancer development and progression has become apparent over the past few years. TGF-beta plays various roles in the process of malignant progression. It is a potent inhibitor of normal stromal, hematopoietic, and epithelial cell growth. However, at some point during cancer development the majority of transformed cells become either partly or completely resistant to TGF-beta growth inhibition. There is growing evidence that in the later stages of cancer development TGF-beta is actively secreted by tumor cells and not merely acts as a bystander but rather contributes to cell growth, invasion, and metastasis and decreases host-tumor immune responses. Subtle alteration of TGF-beta signaling may also contribute to the development of cancer. These various effects are tissue and tumor dependent. Identifying and understanding TGF-beta signaling pathway abnormalities in various malignancies is a promising avenue of study that may yield new modalities to both prevent and treat cancer. The nature, prevalence, and significance of TGF-beta signaling pathway alterations in various forms of human cancer as well as potential preventive and therapeutic interventions are discussed in this review.