Rsf-1 overexpression in human prostate cancer, implication as a prognostic marker

Combination of Ad-SGE-REIC and bevacizumab modulates glioma progression by suppressing tumor invasion and angiogenesis

Reduced expression in immortalized cells/Dickkopf-3 (REIC/Dkk-3) is a tumor suppressor and its overexpression has been shown to exert anti-tumor effects as a therapeutic target gene in many human cancers. Recently, we demonstrated the anti-glioma effects of an adenoviral vector carrying REIC/Dkk-3 with the super gene expression system (Ad-SGE-REIC). Anti-vascular endothelial growth factor treatments such as bevacizumab have demonstrated convincing therapeutic advantage in patients with glioblastoma. However, bevacizumab did not improve overall survival in patients with newly diagnosed glioblastoma. In this study, we examined the effects of Ad-SGE-REIC on glioma treated with bevacizumab. Ad-SGE-REIC treatment resulted in a significant reduction in the number of invasion cells treated with bevacizumab. Western blot analyses revealed the increased expression of several endoplasmic reticulum stress markers in cells treated with both bevacizumab and Ad-SGE-REIC, as well as decreased β-catenin protein levels. In malignant glioma mouse models, overall survival was extended in the combination therapy group. These results suggest that the combination therapy of Ad-SGE-REIC and bevacizumab exerts anti-glioma effects by suppressing the angiogenesis and invasion of tumors. Combined Ad-SGE-REIC and bevacizumab might be a promising strategy for the treatment of malignant glioma.

HELLS, a chromatin remodeler is highly expressed in pancreatic cancer and downregulation of it impairs tumor growth and sensitizes to cisplatin by reexpressing the tumor suppressor TGFBR3

Pancreatic cancer (PC) is the most malignant cancer type in the digestive system with a poor prognosis. Chemotherapy such as cisplatin is the last chance for PC patients diagnosed with advanced or metastatic disease. Obtaining a deep understanding of the molecular mechanism underlying PC tumorigenesis and identifying optimal biomarkers to estimate chemotherapy sensitivity are essential for PC treatment. The chromatin remodeler HELLS was found to regulate various tumor suppressors through an epigenetic pathway in several cancers. We analyzed HELLS expression in clinical samples by Western blotting and immunohistochemical staining. Next, we identified the variation in tumor growth and cisplatin sensitivity after knockdown of HELLS and explored the downstream mediators of HELLS in PC via RNA-seq, chromatin immunoprecipitation, and gain- and loss-of-function assays. We found that HELLS is upregulated in PC tissues and correlates with advanced clinical stage and a poor prognosis, and the knockdown of HELLS leads to tumor growth arrest and increased sensitivity to cisplatin. Mechanistically, the tumor suppressor TGFBR3 is markedly reexpressed after HELLS knockdown; conversely, compromising TGFBR3 rescues HELLS knockdown-mediated effects in PC cells. Thus, our data provide evidence that HELLS can serve as a potential oncogene and suitable biomarker to evaluate chemotherapy sensitivity via epigenetically silencing the tumor suppressor TGFBR3 in PC.

RSF-1 siRNA Enhances Tumor Radiosensitivity in Cervical Cancer via Enhanced DNA Damage, Cell Cycle Redistribution, and Promotion of Apoptosis

Background

Remodeling and spacing factor-1 (RSF-1) is an identified tumor biomarker that is overexpressed in a variety of human cancers, but its effect on radiotherapy remains unclear. In this study, we aimed to explore the effect of RSF-1 siRNA on sensitizing cervical cancer cells to radiation and its underlying mechanism.

Methods

The mRNA and protein expression of RSF-1 in tissue and cells were measured by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. Cell counting kit-8 (CCK-8) and colony formation assay were used to examine cell proliferation. Flow cytometry was used to analyzed the cell cycle and cell apoptosis. DNA damage was examined by the comet assay. ATM, ATR, CHK1, CHK2, H2AX, γH2AX and phosphorylated ATM, ATR, CHK1 and CHK2 were detected by Western blotting. γH2AX foci were demonstrated by immunofluorescence staining.

Results

RSF-1 was upregulated in cervical cancer tissue and decreased after effective treatment. RSF-1 siRNA in combination with radiation suppressed cell viability, redistributed cell cycles and also induced cell apoptosis in HeLa and SiHa cell lines. Further, knockdown of RSF-1 induced DNA damage by attenuating DNA repair capability, thereby sensitizing cervical cancer cells to radiation.

Conclusions

These data demonstrate that RSF-1 siRNA enhanced the sensitivity of radiotherapy, and targeting RSF-1 may be a promising approach for the development of novel radiosensitizing agents for the treatment of cervical cancer.

High RSF1 protein expression is an independent prognostic feature in prostate cancer

Background: Remodelling and spacing factor 1 (RSF1) is involved in the regulation of chromatin remodelling and represents a potential therapeutic target. High RSF1 expression has been linked to adverse tumour features in many cancer types, but its role in prostate cancer is uncertain.Methods: In this study, RSF1 expression was analysed by immunohistochemistry on a tissue microarray with 17,747 prostate cancers.Results: Nuclear RSF1 staining of 16,456 interpetable cancers was considered strong, moderate, weak and negative in 25.2%, 48.7%, 5.3% and 20.8% of cancers respectively. Positive RSF1 expression was associated with advanced tumour stage, high Gleason grade, lymph node metastasis (p < .0001 each), early biochemical recurrence (p < .0003) and more frequent in the ERG positive than in the ERG negative subset (88% versus 71%; p < .0001). Subset analysis revealed, that associations between RSF1 expression and unfavourable tumour phenotype and PSA recurrence were present in both subgroups but stronger in the ERG negative than in the ERG positive subset. The univariate Cox proportional hazard ratio for PSA recurrence-free survival for strong versus negative RSF1 expression was a weak 1.60 compared with 5.91 for the biopsy Gleason grade ≥4 + 4 versus ≤3 + 3. The positive association of RSF1 protein detection with deletion of 3p13, 10q23 (PTEN), 12p13, 16q23, and 17p13 (p < .0001 each) suggest a role of high RSF1 expression in the development of genomic instability.Conclusion: In summary, the results of our study identify RSF1 as an independent prognostic marker in prostate cancer with a particularly strong role in ERG negative cases.

Characterization of HMGB1/2 Interactome in Prostate Cancer by Yeast Two Hybrid Approach: Potential Pathobiological Implications

High mobility group box B (HMGB) proteins are pivotal in the development of cancer. Although the proteomics of prostate cancer (PCa) cells has been reported, the involvement of HMGB proteins and their interactome in PCa is an unexplored field of considerable interest. We describe herein the results of the first HMGB1/HMGB2 interactome approach to PCa. Libraries constructed from the PCa cell line, PC-3, and from patients’ PCa primary tumor have been screened by the yeast 2-hybrid approach (Y2H) using HMGB1 and HMGB2 baits. Functional significance of this PCa HMGB interactome has been validated through expression and prognosis data available on public databases. Copy number alterations (CNA) affecting these newly described HMGB interactome components are more frequent in the most aggressive forms of PCa: those of neuroendocrine origin or castration-resistant PCa. Concordantly, adenocarcinoma PCa samples showing CNA in these genes are also associated with the worse prognosis. These findings open the way to their potential use as discriminatory biomarkers between high and low risk patients. Gene expression of a selected set of these interactome components has been analyzed by qPCR after HMGB1 and HMGB2 silencing. The data show that HMGB1 and HMGB2 control the expression of several of their interactome partners, which might contribute to the orchestrated action of these proteins in PCa

Rsf‑1 regulates malignant melanoma cell viability and chemoresistance via NF‑κB/Bcl‑2 signaling

Remodeling and spacing factor 1 (Rsf-1) has been reported as overexpressed in numerous cancers; however, its expression, biological functions and mechanisms in malignant melanoma remain unknown. In the present study, the expression of Rsf-1 was investigated in 50 cases of malignant melanoma samples using immunohistochemistry. The results revealed that Rsf-1 expression was elevated in 38% of specimens. MTT, colony formation, Transwell and flow cytometry assays were performed to investigate the functions of Rsf-1. Knockdown of Rsf-1 in the MV3 and A375 melanoma cell lines decreased the viability, invasion and cell cycle transition of cells. Conversely, overexpression of Rsf-1 in M14 cells with low endogenous Rsf-1 expression induced opposing effects. Further analysis revealed that Rsf-1 knockdown decreased matrix metalloproteinase-2, cyclin E and phosphorylated-IκB expression. Additionally, Rsf-1 depletion reduced cisplatin resistance and significantly increased the cisplatin-associated apoptotic rate, whereas Rsf-1 overexpression exhibited opposing effects. Rsf-1 also maintained the mitochondrial membrane potential following cisplatin treatment. Analysis of apoptosis-associated proteins revealed that Rsf-1 positively regulated B-cell lymphoma 2 (Bcl-2), cellular inhibitor of apoptosis 1 (cIAP1) and cIAP2, and downregulated Bcl-2-associated X protein expression. Nuclear factor κ-light-chain-enhancer of activated B-cells (NF-κB) inhibition reversed the effects of Rsf-1 on Bcl-2. In conclusion, Rsf-1 was overexpressed in malignant melanoma and may contribute to the malignant behaviors of melanoma cells, possibly via the regulation of NF-κB signaling. Therefore, Rsf-1 may be a potential therapeutic target in the treatment of malignant melanoma.

[Citron Rho-interacting serine/threonine kinase knockdown suppresses prostate cancer cell proliferation and metastasis by blocking Hippo-YAP pathway]

OBJECTIVE

Citron Rho-interacting serine/threonine kinase (CIT) was identified recently as an oncogene involved in the progression of various malignant tumors, but its role in prostate cancer (PCa) remains unclear. In this study, we aimed to investigate the biological functions of CIT in PCa.

METHODS

We analyzed the expression of CIT in PCa tissues and its clinical correlations based on the Cancer Genome Atlas (TCGA) and Memorial Sloan-Kettering Cancer Center (MSKCC) dataset. We then examined the effects of RNA interference-mediated CIT silencing on the proliferation, migration and invasion of PC-3 cells using cell counting kit-8, wound healing assay and Transwell assay. We also investigated the effect of CIT silencing on epithelial-mesenchymal transition (EMT) and Hippo-Yap signaling pathway in the cells using Western blotting.

RESULTS

CIT expression was significantly elevated in PCa tissues from TCGA cohort (P &lt; 0.05). MSKCC dataset analysis showed that an elevated expression of CIT was significantly correlated with N stage (P=0.001), distant metastasis (P &lt; 0.001), Gleason score (P=0.010) and PSA (P=0.004). In cultured PC-3 cells, knockdown of CIT significantly inhibited cell proliferation, migration and invasion, reversed the EMT phenotype and decreased the expression and activity of YAP.

CONCLUSIONS

CIT might function as an oncogene in PCa by modulating the Hippo-YAP signaling pathway and serve as a candidate therapeutic target for PCa.

δ-Catenin Promotes Bevacizumab-Induced Glioma Invasion

The combination of bevacizumab with temozolomide and radiotherapy was shown to prolong progression-free survival in newly diagnosed patients with glioblastoma, and this emphasizes the potential of bevacizumab as a glioma treatment. However, although bevacizumab effectively inhibits angiogenesis, it has also been reported to induce invasive proliferation. This study examined gene expression in glioma cells to investigate the mechanisms of bevacizumab-induced invasion. We made a human glioma U87ΔEGFR cell xenograft model by stereotactically injecting these cells into the brain of animals. We administered bevacizumab intraperitoneally three times per week. At 18 days after tumor implantation, the brains were removed for histopathology and mRNA was extracted. In vivo, bevacizumab treatment increased glioma cell invasion. qRT-PCR array analysis revealed upregulation of δ-catenin (CTNND2) and several other factors. In vitro, bevacizumab treatment upregulated δ-catenin expression. A low concentration of bevacizumab was not cytotoxic, but tumor cell motility was increased in scratch wound assays and two-chamber assays. Overexpression of δ-catenin increased the tumor invasion in vitro and in vivo However, δ-catenin knockdown decreased glioma cell invasiveness. The depth of tumor invasion in the U87ΔEGFR cells expressing δ-catenin was significantly increased compared with empty vector-transfected cells. The increase in invasive capacity induced by bevacizumab therapy was associated with upregulation of δ-catenin expression in invasive tumor cells. This finding suggests that δ-catenin is related to tumor invasion and migration.

Chromatin-remodeling factor, RSF1, controls p53-mediated transcription in apoptosis upon DNA strand breaks

Remodeling and spacing factor 1 (RSF1), which is one of chromatin-remodeling factors, has been linked to the DNA damage response (DDR) and DNA repair. However, the biological consequence of RSF1 deficiency in DDR in vivo and its molecular mechanisms remain unknown. Because defective DDR is related to neuropathological phenotypes, we developed neural-specific Rsf1 knockout mice. Rsf1 deficiency did not result in any neuropathological abnormalities, but prevented neural apoptosis triggered by excessive DNA strand breaks during neurogenesis. Likewise, cell death was significantly reduced in RSF1 deficient human cell lines after DNA damage, and the global transcriptome of these cells revealed that the expressions of p53 downstream genes were significantly reduced upon DNA strand breaks. Inactivation of these genes resulted from decreased binding of p53/p300 complex and subsequent reduction of H3 acetylation at their promoters. Our data show that RSF1 is necessary for p53-dependent gene expression in response to DNA strand breaks via controlling the accessibility of p53/p300 complex to its target genes and contributes to the maintenance of cellular integrity.

LncRNA NEAT1/let-7a-5p axis regulates the cisplatin resistance in nasopharyngeal carcinoma by targeting Rsf-1 and modulating the Ras-MAPK pathway

The long non-coding RNA nuclear paraspeckle assembly transcript 1 (NEAT1) was reported to be upregulated and be involved in oncogenic growth and drug resistance in nasopharyngeal carcinoma (NPC). However, the exact roles of NEAT1 and its underlying mechanisms in the drug resistance of NPC remain largely unclear. In this study, the expressions of NEAT1, let-72-5p and Rsf-1 mRNA were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The effects of NEAT1 and let-72-5p on cell proliferation and cisplatin resistance of NPC cells were investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and 5-ethynyl-20-deoxyuridine (EdU) assay. Western blot analysis was performed to detect the protein levels of Rsf-1, Ras, p-Raf1, Raf1, p-MEK1, MEK1, p-ERK1/2 and ERK1/2. Xenograft tumor assay was done to elucidate the role of NEAT1 involved in NPC tumor growth in vivo. We found that NEAT1 was upregulated and let-7a-5p was downregulated in NPC tissues, as well as NPC cell lines. Inhibition of NEAT1 markedly repressed the cisplatin resistance of NPC cells. NEAT1 was demonstrated to interact with let-7a-5p. Besides, a negative correlation between NEAT1 and let-7a-5p expression was observed in NPC tissues. Rsf-1 was confirmed as a target of let-7a-5p. NEAT1 remarkably reversed the inhibitory effect of let-7q-5p on the cisplatin resistance of NPC cells in vitro. Additionally, NEAT1 knockdown inhibited the Ras-MAPK pathway in NPC cells. NEAT1 knockdown suppressed tumor growth in the presence of cisplatin in vivo. Overall, these findings suggest that NEAT1/let-7a-5p axis regulates the cisplatin resistance in NPC by targeting Rsf-1 and modulating the Ras-MAPK signaling pathway.

RSF-1 overexpression determines cancer progression and drug resistance in cervical cancer

BACKGROUND

Remodeling spacing factor 1 (RSF-1/HBXAP) has been linked to a variety of cancer types, however, its roles and the therapeutic potential are not clear in cervical cancer.

METHODS

RSF-1 expression in cancer tissues was analyzed by immunohistochemical staining followed by statistical analysis with SPSS. Anti-RSF-1 studies were performed by treating cells with specific siRNA or a dominant mutant form (RSF-D4).

RESULTS

RSF-1 expression correlates with cancer progression that strongly-positive staining can be found in 67.7% carcinomas and 66.7% CIN lesions, but none in normal tissues. Such overexpression also associated with increased tumor size, poor differentiation, higher nodal metastasis and advanced clinical stages. Kaplan- Meier analysis confirmed that cancer patients with high RSF-1 levels exhibited a significantly shorter survival time than those with low RSF-1 levels. Downregulation of RSF-1 by siRNA silencing or RSF-D4 reduced cell growth and increased drug sensitivity toward paclitaxel treatment in HeLa cells.

CONCLUSIONS

RSF-1 participates in the tumor progression of cervical cancer and could be considered as an early prognostic marker for cancer development and clinical outcome. Therapies based on anti-RSF-1 activity may be beneficial for patients with RSF-1 overexpression in their tumors.

Remodeling and spacing factor 1 overexpression is associated with poor prognosis in renal cell carcinoma

The present study aimed to assess the expression and prognostic significance of remodeling and spacing factor 1 (RSF1; HBXAP) in renal cell carcinoma (RCC). RSF1 expression was analyzed using immunohistochemistry on tissue samples from a consecutive series of 137 patients with RCC who underwent tumor resection between November 2000 and March 2004. The associations between RSF1 expression, clinicopathological factors and patient survival were investigated. Immunohistochemistry revealed that RSF1 was highly expressed in 43.1% (59/137) of the RCC samples. RSF1 expression levels were associated with the T stage of the Tumor-Node-Metastasis grading system. Kaplan-Meier survival analysis indicated that high RSF1 expression in RCC was significantly associated with a poor prognosis. Multivariate analysis revealed that RSF1 expression is an independent prognostic parameter for the duration of overall survival of patients with RCC. The results demonstrated that a high expression level of RSF1 in RCC is associated with advanced tumor stages and a poor prognosis. To the best of our knowledge, the present study provides novel evidence of the biological significance of RSF1 expression in RCC.

RSF1 functions as an oncogene in osteosarcoma and is regulated by XIST/miR-193a-3p axis

RSF1 (HBXAP), is a member of ATP-dependent chromatin remodeling factor. Dysregulated RSF1 has been reported to be related to tumor progression. However, the function of RSF1 in osteosarcoma (OS) remains unclear. In this study, we showed that RSF1 expression was upregulated in OS cells. RSF1 inhibition suppressed OS cell proliferation and invasion. We further showed that MAPK/Erk signaling pathway was inactivated by RSF1 suppression. In addition, RSF1 was identified as a direct target of miR-193a-3p. Clinically, RSF1 was increased and associated with advanced clinical features and poor overall survival of OS patients. MiR-193a-3p expression was decreased and associated with advanced clinical features and poor overall survival of OS patients. In addition, we found that miR-193a-3p was negatively correlated with RSF1 expression in OS tissues. Moreover, our data showed that XIST could function as competing endogenous RNA to repress miR-193a-3p, which regulated its downstream target RSF1. In conclusion, our findings demonstrated that the XIST/miR-193a-3p/RSF1 axis might contribute to the progression and act as a therapeutic target of OS patients.

RSF1 regulates the proliferation and paclitaxel resistance via modulating NF-κB signaling pathway in nasopharyngeal carcinoma

Purpose: Aberrant expression and dysfunction of RSF1 has been reported in diverse human malignancies. However, its exact role in nasopharyngeal carcinoma (NPC) remains unclear.

Methods: The expression of RSF1 mRNA and protein were assayed by qRT-PCR and western blotting, and their correlations with clinicopathological parameters of patients with NPC were further analysed. Lentivirus mediated RSF1 shRNA and RSF1 cDNA were used to knockdown and upregulate the expression of RSF1. CCK8 assays and flow cytometry were applied to monitor the changes of proliferation and paclitaxel sensitivity caused by RSF1 modulation, inhibition of NF-κB pathway by inhibitor Bay 11-7082 and Survivin knockdown. Western blotting was used to detect protein alterations in NF-κB signaling pathway.

Results: Our present study demonstrated that both mRNA and protein expressions of RSF1 were increased and correlated with advanced NPC clinical stage. Functional analyses revealed that RSF1 inhibition or overexpression induced changes in cell cycle, apoptosis, and then led to altered proliferation and paclitaxel sensitivity in diverse NPC cells in vitro. Further mechanism investigation hinted that RSF1 overexpression in NPC CNE-2 cells activated NF-κB pathway and promoted the expression NF-κB dependent genes involved in cell cycle and apoptosis including Survivin. Importantly, inhibition of NF-κB pathway by Bay 11-7082 and knockdown its downstream Survivin reversed the paclitaxel resistance caused by RSF1 overexpression.

Conclusions: Taken together, our data indicate that RSF1 regulates the proliferation and paclitaxel resistance via activating NF-κB signaling pathway and NF-κB-dependent Survivin upregulation, suggesting that RSF1 may be used as a potential therapeutic target in NPC.

Epigenomic regulation of oncogenesis by chromatin remodeling

Disruption of the intricate gene expression program represents one of major driving factors for the development, progression and maintenance of human cancer, and is often associated with acquired therapeutic resistance. At the molecular level, cancerous phenotypes are the outcome of cellular functions of critical genes, regulatory interactions of histones and chromatin remodeling complexes in response to dynamic and persistent upstream signals. A large body of genetic and biochemical evidence suggests that the chromatin remodelers integrate the extracellular and cytoplasmic signals to control gene activity. Consequently, widespread dysregulation of chromatin remodelers and the resulting inappropriate expression of regulatory genes, together, lead to oncogenesis. We summarize the recent developments and current state of the dysregulation of the chromatin remodeling components as the driving mechanism underlying the growth and progression of human tumors. Because chromatin remodelers, modifying enzymes and protein-protein interactions participate in interpreting the epigenetic code, selective chromatin remodelers and bromodomains have emerged as new frontiers for pharmacological intervention to develop future anti-cancer strategies to be used either as single-agent or in combination therapies with chemotherapeutics or radiotherapy.

Overexpression of hSNF2H in glioma promotes cell proliferation, invasion, and chemoresistance through its interaction with Rsf-1

hSNF2H partners with Rsf-1 to compose the Rsf complex to regulate gene expression. Recent studies indicated that hSNF2H was overexpressed in several human cancers. However, its expression pattern and biological mechanism in glioma remain unexplored. In this study, we found that hSNF2H was overexpressed in 32 % of glioma specimens. hSNF2H overexpression correlated with advanced tumor grade (p = 0.0338) and Rsf-1 positivity in glioma tissues (p = 0.016). Small interfering RNA (siRNA) knockdown was performed in A172 and U87 cell lines. MTT, colony formation assay, and cell cycle analysis showed that knockdown of hSNF2H inhibited cell proliferation, colony formation ability, and cell cycle transition. Matrigel invasion assay showed that hSNF2H depletion inhibited invasive ability of glioma cells. In addition, we demonstrated that hSNF2H depletion decreased temozolomide resistance of A172 and U87 cell lines and increased temozolomide induced apoptosis. Furthermore, hSNF2H depletion decreased cyclin D1, cyclin E, p-Rb, MMP2, cIAP1, Bcl-2 expression, and phosphorylation of IκBα and p65, suggesting hSNF2H regulates apoptosis through NF-κB pathway. Immunoprecipitation showed that hSNF2H could interact with Rsf-1 in both cell lines. To validate the involvement of Rsf-1, we checked the change of its downstream targets in Rsf-1 depleted cells. In Rsf-1 depleted cells, changes of cyclin E, Bcl-2, and p-IκBα were not significant using hSNF2H siRNA treatment. In conclusion, our study demonstrated that hSNF2H was overexpressed in human gliomas and contributed to glioma proliferation, invasion, and chemoresistance through regulation of cyclin E and NF-κB pathway, which is dependent on its interaction with Rsf-1.