Transcription factor ZBP-89 in cancer growth and apoptosis

Targeting the ZNF-148/miR-335/SOD2 signaling cascade triggers oxidative stress-mediated pyroptosis and suppresses breast cancer progression

BACKGROUND

The implication of zinc finger protein 148 (ZNF-148) in pathophysiology of most human cancers has been reported; however, the biological functions of ZNF-148 in breast cancer remain unclear. This study sought to elucidate the potential molecular mechanism of ZNF-148 on breast cancer pathology.

METHODS

ZNF148 expression was tested in breast cancer tissues and cells. Then, cells were transfected with ZNF-148 overexpression or downregulation vector, and the cell proliferation, pyroptosis, apoptosis, and reactive oxygen species (ROS) production were analyzed by MTT, western blot, flow cytometry, and immunofluorescence staining, respectively. Tumor-bearing nude mouse was used to evaluate tumorigenesis of ZNF-148. Mechanisms underpinning ZNF-148 were examined using bioinformatics and luciferase assays.

RESULTS

We found that ZNF-148 was upregulated in breast cancer tissues and cell lines. Knockdown of ZNF-148 suppressed malignant phenotypes, including cell proliferation, epithelial-mesenchymal transition, and tumorigenesis in vitro and in vivo, while ZNF-148 overexpression had the opposite effects. Further experiments showed that ZNF-148 deficiency promoted ROS production and triggered both apoptotic and pyroptotic cell death, which were restored by cotreating cells with ROS scavengers. A luciferase reporter assay revealed that miR-335 was the downstream target of ZNF-148 and that overexpressed ZNF-148 increased superoxide dismutase 2 (SOD2) expression by sponging miR-335. In parallel, both miR-335 downregulation and SOD2 overexpression abrogated the antitumor effects of ZNF-148 deficiency on proliferation and pyroptosis in breast cancer cells.

CONCLUSIONS

Our findings indicated that ZNF-148 promotes breast cancer progression by triggering miR-335/SOD2/ROS-mediated pyroptotic cell death and aid the identification of potential therapeutic targets for breast cancer.

Understanding the regulation of β-catenin expression and activity in colorectal cancer carcinogenesis: beyond destruction complex

Aberrant Wnt/β-catenin signaling is central to colorectal cancer carcinogenesis. The well-known potential of targeting the canonical Wnt signaling pathway for the treatment of CRC is largely attributed to the ability of this pathway to regulate various cellular processes such as cell proliferation, metastasis, drug resistance, immune response, apoptosis, and cellular metabolism. However, with the current approach of targeting this pathway, none of the Wnt-targeted agents have been successfully implicated in clinical practice. Instead of using classical approaches to target this pathway, there is a growing need to find new and modified approaches to achieve the same. For this, a better understanding of the regulation of β-catenin, a major effector of the canonical Wnt pathway is a must. The present review addresses the importance of understanding the regulation of β-catenin beyond the destruction complex. Few recently discovered β-catenin regulators such as ZNF281, TTPAL, AGR2, ARHGAP25, TREM2, and TIPE1 showed significant potential in regulating the development of CRC through modulation of the Wnt/β-catenin signaling pathway in both in vitro and in vivo studies. Although the expression and activity of β-catenin is influenced by many protein regulators, the abovementioned proteins not only influence its expression and activation but are also directly involved in the development of CRC and various other solid tumors. Therefore, we hypothesise that focusing the current research on finding the detailed mechanism of action of these regulators may assist in providing with a better treatment approach or improve the current therapeutic regimens.

Upregulation of ZNF148 in SDHB-deficient gastrointestinal stromal tumor potentiates Forkhead box M1-mediated transcription and promotes tumor cell invasion

Succinate dehydrogenase (SDH) deficiency is associated with gastrointestinal stromal tumor (GIST) oncogenesis, but the underlying molecular mechanism remains to be further investigated. Here, we show that succinate accumulation induced by SDHB loss of function increased the expression of zinc finger protein 148 (ZNF148, also named ZBP-89) in GIST cells. Meanwhile, ZNF148 is found to be phosphorylated by ERK at Ser306, and this phosphorylation results in ZNF148 binding to Forkhead box M1 (FOXM1). Through the complex formation at the promoter, ZNF148 facilitates Histone H3 acetylation and FOXM1-mediated Snail transcription, which eventually promotes cell invasion and tumor growth. The clinical analysis indicates that SDHB deficiency is associated with elevated ZNF148 levels, and ZNF148-S306 phosphorylation level displays a positive correlation with poor prognosis in GIST patients. These findings illustrate an unidentified molecular mechanism underlying FOXM1-regulated gene transcription related to GIST cell invasion, which highlights the physiological effects of SDHB deficiency on the invasiveness of GIST.

ZBP-89 negatively regulates self-renewal of liver cancer stem cells via suppression of Notch1 signaling pathway

Liver cancer stem cells (LCSCs) initiate hepatocellular carcinoma (HCC) and contribute to its recurrence and treatment resistance. Studies have suggested ZBP-89 as a candidate tumor suppressor in HCC. We explored the role of ZBP-89 in the regulation of LCSCs. This study was performed in liver tissue samples from 104 HCC patients, 2 cell lines and mouse tumor models. We demonstrated that ZBP-89 was weakly expressed in LCSCs. Patients with high expression of LCSC markers displayed reduced survivals and higher recurrence rates after curative surgical operation. The expression of ZBP-89 was predictive for decreased recurrence. LCSC markers were negatively correlated with ZBP-89 in HCC tissues and in enriched liver tumor spheres. The exogenous expression of ZBP-89 attenuated the tumor-sphere formation and secondary colony formation capabilities of LCSCs in vitro and tumorigenicity in vivo. Furthermore, the negative effect of ZBP-89 on cancer stemness was Notch1-dependent. Localized with Notch1 intracellular domain (NICD1) in the nucleus, ZBP-89 repressed the Notch1 signaling pathway by competitive binding to NICD1 with MAML1. Collectively, ZBP-89 negatively regulates HCC stemness via inhibiting the Notch1 signaling.

Regulation between two alternative splicing isoforms ZNF148FL and ZNF148ΔN, and their roles in the apoptosis and invasion of colorectal cancer

OBJECTIVE

To investigate the effect of two alternative splicing isoforms of zinc finger protein (ZNF) 148 gene on the invasion and metastasis of human colorectal cancer (CRC) cells and their related mechanisms.

METHODS

Quantitative RT-PCR assays were used to detect the expression of twoZNF148 alternative splicing isoforms in SW480 cells. ZNF148^FL-siRNA, ZNF148^FL-over express vector, ZNF148^ΔN-siRNA, and ZNF148^ΔN-over express vector were introduced into SW480 cells. The transfection efficiency was confirmed by RT-PCR. The proliferation, invasion, and migration in vitro as well as the apoptosis of SW480 cells were detected by MTT, transwell, scratch assay and flow cytometry, respectively.

RESULTS

Both ZNF148^FL and ZNF148^ΔN were expressed in SW480 cells, and the level of ZNF148^FL protein was higher than ZNF148^ΔN. After ZNF148^FL-siRNA and ZNF148^ΔN-over express transfection, the expression level of ZNF148^FL and ZNF148Δ^N were significantly decreased and increased, respectively. In contrast, the expression of ZNF148^FL and ZNF148^ΔN were significantly increased and decreased, respectively, after ZNF148^FL-over express and ZNF148^ΔN-siRNA transfection (all P < 0.05). The proliferation of SW480 cells was increased in ZNF148^FL-over express group and the ZNF148^ΔN-siRNA group, while decreased in ZNF148^FL-siRNA group and ZNF148^ΔN-over express group. The invaded cell number and migrated distance in ZNF148^FL-siRNA group and ZNF148^ΔN-over express group were significantly decreased, but the apoptotic rate was significantly increased. In contrast, ZNF148^FL-over express and ZNF148^ΔN-siRNA group showed the significantly increased ability of invasion and migration but decreased apoptosis rate (all P < 0.05).

CONCLUSION

ZNF148^FL could increase proliferation, invasion, and migration of CRC cells, while ZNF148^ΔN showed opposite effect; the two splicing isoforms of ZNF148 may exert a mutual antagonistic effect to each other on the malignant biological activities.

Modulating the expression of Chtop, a versatile regulator of gene-specific transcription and mRNA export

Chtop binds competitively to the arginine methyltransferases PRMT1 and PRMT5, thereby promoting the asymmetric or symmetric methylation of arginine residues, respectively. In cooperation with PRMT1, Chtop activates transcription of certain gene groups, such as the estrogen-inducible genes in breast cancer cells, the 5-hydroxymethylcytosine-modified genes involved in glioblastomagenesis, or the Zbp-89-dependent genes in erythroleukemia cells. Chtop also represses expression of the fetal γ-globin gene. In addition, Chtop is a component of the TREX complex that links transcription elongation to mRNA export. The regulation of Chtop expression is, therefore, a key process during the expression of certain gene groups and pathogenesis of certain diseases. Our recent study revealed that cellular levels of Chtop are strictly autoregulated by a mechanism involving intron retention and nonsense-mediated mRNA decay. Here, we summarize roles of Chtop in gene-specific expression and highlight our recent findings concerning the autoregulation of Chtop.

Peritumoral overexpression of ZBP-89 is associated with unfavorable disease-free survival rates in patients with hepatocellular carcinoma following hepatectomy

Previous studies have revealed that the peritumoral environment has a profound influence on tumor initiation and progression. Zinc-binding protein-89 (ZBP-89) has been observed to be involved with tumor development, recurrence, and metastasis. High intratumoral expression of ZBP-89 has been associated with improved prognosis in several tumor types. However, the prognostic values of peritumoral expression of ZBP-89 remain to be elucidated in patients with hepatocellular carcinoma (HCC) following curative resection. In the present study, peritumoral ZBP-89 expression was examined using immunohistochemistry in 102 HCC patients who had received curative hepatectomy. Expression of ZBP-89 protein was positive in 66.3% of the peritumoral samples from 102 HCC patients. HCC patients with high peritumoral ZBP-89 expression exhibited significantly shorter disease-free survival (DFS) times (P=0.012) than those patients with low peritumoral ZBP-89 expression. Additionally, high ZBP-89 expression in peritumoral HCC tissue was positively associated with the presence of liver cirrhosis. Univariate and multivariate Cox proportional hazard regression analyses demonstrated that albumin levels ≤35 g/l, multiple tumors, tumor sizes ≥5 cm, and macroscopic vascular invasion may serve as independent prognostic factors for overall survival (OS) [hazard ratio (HR)=2.031; P=0.014] in patients with HCC. The multivariate Cox regression model identified that high ZBP-89 expression, multiple tumors and macroscopic vascular invasion were independent prognostic factors for shorter DFS durations. High expression of ZBP-89 in peritumoral HCC tissues was associated with a shorter DFS in HCC patients following curative hepatectomy. Additionally, high ZBP-89 expression in peritumoral HCC tissue was positively associated with the presence of liver cirrhosis in HCC patients, indicating that cirrhosis accompanied by high ZBP-89 expression may be a contributing factor to the poor prognosis of patients with HCC. Therefore, peritumoral ZBP-89 expression may be a good prognostic marker to predict DFS time in HCC patients following curative hepatectomy and may provide novel insights into the molecular mechanisms of HCC initiation.

Functional characterization of a multi-cancer risk locus on chr5p15.33 reveals regulation of TERT by ZNF148

Genome wide association studies (GWAS) have mapped multiple independent cancer susceptibility loci to chr5p15.33. Here, we show that fine-mapping of pancreatic and testicular cancer GWAS within one of these loci (Region 2 in CLPTM1L) focuses the signal to nine highly correlated SNPs. Of these, rs36115365-C associated with increased pancreatic and testicular but decreased lung cancer and melanoma risk, and exhibited preferred protein-binding and enhanced regulatory activity. Transcriptional gene silencing of this regulatory element repressed TERT expression in an allele-specific manner. Proteomic analysis identifies allele-preferred binding of Zinc finger protein 148 (ZNF148) to rs36115365-C, further supported by binding of purified recombinant ZNF148. Knockdown of ZNF148 results in reduced TERT expression, telomerase activity and telomere length. Our results indicate that the association with chr5p15.33-Region 2 may be explained by rs36115365, a variant influencing TERT expression via ZNF148 in a manner consistent with elevated TERT in carriers of the C allele.

New factors in mammalian DNA repair-the chromatin connection

In response to DNA damage mammalian cells activate a complex network of stress response pathways collectively termed DNA damage response (DDR). DDR involves a temporary arrest of the cell cycle to allow for the repair of the damage. DDR also attenuates gene expression by silencing global transcription and translation. Main function of DDR is, however, to prevent the fixation of debilitating changes to DNA by activation of various DNA repair pathways. Proper execution of DDR requires careful coordination between these interdependent cellular responses. Deregulation of some aspects of DDR orchestration is potentially pathological and could lead to various undesired outcomes such as DNA translocations, cellular transformation or acute cell death. It is thus critical to understand the regulation of DDR in cells especially in the light of a strong linkage between the DDR impairment and the occurrence of common human diseases such as cancer. In this review we focus on recent advances in understanding of mammalian DNA repair regulation and a on the function of PAXX/c9orf142 and ZNF281 proteins that recently had been discovered to play a role in that process. We focus on regulation of double-strand DNA break (DSB) repair via the non-homologous end joining pathway, as unrepaired DSBs are the primary cause of pathological cellular states after DNA damage. Interestingly these new factors operate at the level of chromatin, which reinforces a notion of a central role of chromatin structure in the regulation of cellular DDR regulation.

ZNF148 modulates TOP2A expression and cell proliferation via ceRNA regulatory mechanism in colorectal cancer

BACKGROUND

Competing endogenous RNA (ceRNA) regulation is a novel hypothesized mechanism that states RNA molecules share common target microRNAs (miRNAs) and may competitively combine into the same miRNA pool.

METHODS

Zinc finger protein 148 (ZNF148) and TOP2A expression were analyzed in 742 colorectal cancer (CRC) tissues using immunohistochemistry (IHC). ZNF148 mRNA, TOP2A mRNA, miR101, miR144, miR335, and miR365 expression were estimated in 53 fresh frozen CRC tissues by reverse transcription polymerase chain reaction. Mechanisms underpinning ceRNA were examined using bioinformatics, correlation analysis, RNA interference, gene over-expression, and luciferase assays.

RESULTS

Protein levels of ZNF148 and TOP2A detected by IHC positively correlated (Spearman correlation coefficient [rs] = 0.431, P < 0.001); mRNA levels of ZNF148 and TOP2A also positively correlated (r = 0.591, P < 0.001). Bioinformatics analysis demonstrated that ZNF148 and TOP2A mRNA had 13 common target miRNAs, including miR101, miR144, miR335, and miR365. Correlation analysis demonstrated that levels of ZNF148 mRNA were negatively associated with levels of miR144, miR335, and miR365. Knockdown and overexpression tests showed that ZNF148 mRNA and TOP2A mRNA regulated each other in HCT116 cells, respectively, but not in Dicer-deficient HCT116 cells. Luciferase assays demonstrated that ZNF148 and TOP2A regulated each other through 3'UTR. Overexpression of ZNF148 mRNA and TOP2A mRNA caused significant downregulation of miR101, miR144, miR335, and miR365 in the HCT116 cells. We also found that knockdown of ZNF148 and TOP2A significantly promoted cell growth, and overexpression of ZNF148 and TOP2A inhibited cell proliferation, which was abrogated in Dicer-deficient HCT116 cells.

CONCLUSION

ZNF148 and TOP2A regulate each other through ceRNA regulatory mechanism in CRC, which has biological effects on cell proliferation.

Implications of Genetic and Epigenetic Alterations of CDKN2A (p16(INK4a)) in Cancer

Aberrant gene silencing is highly associated with altered cell cycle regulation during carcinogenesis. In particular, silencing of the CDKN2A tumor suppressor gene, which encodes the p16(INK4a) protein, has a causal link with several different types of cancers. The p16(INK4a) protein plays an executional role in cell cycle and senescence through the regulation of the cyclin-dependent kinase (CDK) 4/6 and cyclin D complexes. Several genetic and epigenetic aberrations of CDKN2A lead to enhanced tumorigenesis and metastasis with recurrence of cancer and poor prognosis. In these cases, the restoration of genetic and epigenetic reactivation of CDKN2A is a practical approach for the prevention and therapy of cancer. This review highlights the genetic status of CDKN2A as a prognostic and predictive biomarker in various cancers.

MPTP's pathway of toxicity indicates central role of transcription factor SP1

Deriving a Pathway of Toxicity from transcriptomic data remains a challenging task. We explore the use of weighted gene correlation network analysis (WGCNA) to extract an initial network from a small microarray study of MPTP toxicity in mice. Five modules were statistically significant; each module was analyzed for gene signatures in the Chemical and Genetic Perturbation subset of the Molecular Signatures Database as well as for over-represented transcription factor binding sites and WGCNA clustered probes by function and captured pathways relevant to neurodegenerative disorders. The resulting network was analyzed for transcription factor candidates, which were narrowed down via text-mining for relevance to the disease model, and then combined with the large-scale interaction FANTOM4 database to generate a genetic regulatory network. Modules were enriched for transcription factors relevant to Parkinson's disease. Transcription factors significantly improved the number of genes that could be connected in a given component. For each module, the transcription factor that had, by far, the highest number of interactions was SP1, and it also had substantial experimental evidence of interactions. This analysis both captures much of the known biology of MPTP toxicity and suggests several candidates for further study. Furthermore, the analysis strongly suggests that SP1 plays a central role in coordinating the cellular response to MPTP toxicity.

Computational identification of surrogate genes for prostate cancer phases using machine learning and molecular network analysis

BACKGROUND

Prostate cancer is one of the most common malignant diseases and is characterized by heterogeneity in the clinical course. To date, there are no efficient morphologic features or genomic biomarkers that can characterize the phenotypes of the cancer, especially with regard to metastasis--the most adverse outcome. Searching for effective surrogate genes out of large quantities of gene expression data is a key to cancer phenotyping and/or understanding molecular mechanisms underlying prostate cancer development.

RESULTS

Using the maximum relevance minimum redundancy (mRMR) method on microarray data from normal tissues, primary tumors and metastatic tumors, we identifed four genes that can optimally classify samples of different prostate cancer phases. Moreover, we constructed a molecular interaction network with existing bioinformatic resources and co-identifed eight genes on the shortest-paths among the mRMR-identified genes, which are potential co-acting factors of prostate cancer. Functional analyses show that molecular functions involved in cell communication, hormone-receptor mediated signaling, and transcription regulation play important roles in the development of prostate cancer.

CONCLUSION

We conclude that the surrogate genes we have selected compose an effective classifier of prostate cancer phases, which corresponds to a minimum characterization of cancer phenotypes on the molecular level. Along with their molecular interaction partners, it is fairly to assume that these genes may have important roles in prostate cancer development; particularly, the un-reported genes may bring new insights for the understanding of the molecular mechanisms. Thus our results may serve as a candidate gene set for further functional studies.

Nicotine-mediated invasion and migration of non-small cell lung carcinoma cells by modulating STMN3 and GSPT1 genes in an ID1-dependent manner

Background

Inhibitor of DNA binding/Differentiation 1 (ID1) is a helix loop helix transcription factor that lacks the basic DNA binding domain. Over-expression of ID1 has been correlated with a variety of human cancers; our earlier studies had shown that reported ID1 is induced by nicotine or EGF stimulation of non-small cell lung cancer (NSCLC) cells and its down regulation abrogates cell proliferation, invasion and migration. Here we made attempts to identify downstream targets of ID1 that mediate these effects.

Methods

A microarray analysis was done on two different NSCLC cell lines (A549 and H1650) that were transfected with a siRNA to ID1 or a control, non-targeting siRNA. Cells were stimulated with nicotine and genes that were differentially expressed upon nicotine stimulation and ID1 depletion were analyzed to identify potential downstream targets of ID1. The prospective role of the identified genes was validated by RT-PCR. Additional functional assays were conducted to assess the role of these genes in nicotine induced proliferation, invasion and migration. Experiments were also conducted to elucidate the role of ID1, which does not bind to DNA directly, affects the expression of these genes at transcriptional level.

Results

A microarray analysis showed multiple genes are affected by the depletion of ID1; we focused on two of them: Stathmin-like3 (STMN3), a microtubule destabilizing protein, and GSPT1, a protein involved in translation termination; these proteins were induced by both nicotine and EGF in an ID1 dependent fashion. Overexpression of ID1 in two different cell lines induced STMN3 and GSPT1 at the transcriptional level, while depletion of ID1 reduced their expression. STMN3 and GSPT1 were found to facilitate the proliferation, invasion and migration of NSCLC cells in response to nAChR activation. Attempts made to assess how ID1, which is a transcriptional repressor, induces these genes showed that ID1 down regulates the expression of two transcriptional co-repressors, NRSF and ZBP89, involved in the repression of these genes.

Conclusions

Collectively, our data suggests that nicotine and EGF induce genes such as STMN3 and GSPT1 to promote the proliferation, invasion and migration of NSCLC, thus enhancing their tumorigenic properties. These studies thus reveal a central role for ID1 and its downstream targets in facilitating lung cancer progression.

Apoptosis and other immune biomarkers predict influenza vaccine responsiveness

Despite the importance of the immune system in many diseases, there are currently no objective benchmarks of immunological health. In an effort to identifying such markers, we used influenza vaccination in 30 young (20-30 years) and 59 older subjects (60 to >89 years) as models for strong and weak immune responses, respectively, and assayed their serological responses to influenza strains as well as a wide variety of other parameters, including gene expression, antibodies to hemagglutinin peptides, serum cytokines, cell subset phenotypes and in vitro cytokine stimulation. Using machine learning, we identified nine variables that predict the antibody response with 84% accuracy. Two of these variables are involved in apoptosis, which positively associated with the response to vaccination and was confirmed to be a contributor to vaccine responsiveness in mice. The identification of these biomarkers provides new insights into what immune features may be most important for immune health.

MicroRNA-203 enhances coxsackievirus B3 replication through targeting zinc finger protein-148

Coxsackievirus B3 (CVB3) is the primary causal agent of viral myocarditis. During infection, it hijacks host genes to favour its own replication. However, the underlying mechanism is still unclear. Although the viral receptor is an important factor for viral infectivity, other factors such as microRNAs (miRNA) may also play an essential role in its replication after host cell entry. miRNAs are post-transcriptional gene regulators involved in various fundamental biological processes as well as in diseases. To identify miRNAs involved in CVB3 pathogenesis, we performed microarray analysis of miRNAs using CVB3-infected murine hearts and identified miR-203 as one of the most upregulated candidates. We found that miR-203 upregulation is through the activation of protein kinase C/transcription factor AP-1 pathway. We further identified zinc finger protein-148 (ZFP-148), a transcription factor, as a novel target of miR-203. Ectopic expression of miR-203 downregulated ZFP-148 translation, increased cell viability and subsequently enhanced CVB3 replication. Silencing of ZFP-148 by siRNA showed similar effects on CVB3 replication. Finally, analyses of the signalling cascade downstream of ZFP-148 revealed that miR-203-induced suppression of ZFP-148 differentially regulated the expression of prosurvival and proapoptotic genes of the Bcl-2 family proteins as well as the cell cycle regulators. This altered gene expression promoted cell survival and growth, which provided a favourable environment for CVB3 replication, contributing to the further damage of the infected cells. Taken together, this study identified a novel target of miR-203 and revealed, for the first time, the molecular link between miR-203/ZFP-148 and the pathogenesis of CVB3.

Anti-oncogenic microRNA-203 induces senescence by targeting E2F3 protein in human melanoma cells

MicroRNAs regulate gene expression by repressing translation or directing sequence-specific degradation of their complementary mRNA. We recently reported that miR-203 is down-regulated, and its exogenous expression inhibits cell growth in canine oral malignant melanoma tissue specimens as well as in canine and human malignant melanoma cells. A microRNA target database predicted E2F3 and ZBP-89 as putative targets of microRNA-203 (miR-203). The expression levels of E2F3a, E2F3b, and ZBP-89 were markedly up-regulated in human malignant melanoma Mewo cells compared with those in human epidermal melanocytes. miR-203 significantly suppressed the luciferase activity of reporter plasmids containing the 3'-UTR sequence of either E2F3 or ZBP-89 complementary to miR-203. The ectopic expression of miR-203 in melanoma cells reduced the levels of E2F3a, E2F3b, and ZBP-89 protein expression. At the same time, miR-203 induced cell cycle arrest and senescence phenotypes, such as elevated expression of hypophosphorylated retinoblastoma and other markers for senescence. Silencing of E2F3, but not of ZBP-89, inhibited cell growth and induced cell cycle arrest and senescence. These results demonstrate a novel role for miR-203 as a tumor suppressor acting by inducing senescence in melanoma cells.

Interaction between ZBP-89 and p53 mutants and its contribution to effects of HDACi on hepatocellular carcinoma

ZBP-89, a zinc finger transcription factor, participates in histone deacetylases inhibitors (HDACi)-mediated growth arrest and apoptosis in cancer cells. p53 mutants may interact with ZBP-89 that transcriptionally regulates p21(Waf1) (p21). However, this interaction and its consequence in cancer treatments are poorly understood. In this study, we demonstrate that ZBP‑89 is essentially required in HDACi-mediated p21 upregulation in hepetocellular carcinoma (HCC). Overexpression of ZBP-89 protein enhanced the lethal effectiveness of Trichostatin A (TSA). p53 mutant p53(G245D), but not p53(R249S), directly bound to ZBP-89 and prevented its translocation from cytoplasm to nucleus. Furthermore, p53(G245D) was shown to have a similar pattern of subcellular localization to ZBP-89 in tissues of HCC patients in Hong Kong. Functionally, the cytoplasmic accumulation of ZBP-89 by p53(G245D) significantly abrogated the induction of p21 caused by sodium butyrate (NaB) treatment and protected cells from TSA-induced death. The activations of several apoptotic proteins, such as Bid and PARP, were involved in p53(G245D)-mediated protection. Moreover, the resistance to HDACi in p53(G245D)-expressing cells was reversed by overexpression of ZBP-89. Taken together, these data suggest a potential mechanism via which mutant p53 enables tumor cells to resist chemotherapy and, therefore, establish a plausible link between mutant p53 binding to ZBP-89 and a decreased chemosensitivity of HCC cells.

ID1 facilitates the growth and metastasis of non-small cell lung cancer in response to nicotinic acetylcholine receptor and epidermal growth factor receptor signaling

Expression of ID1 (inhibitor of differentiation) has been correlated with the progression of a variety of cancers, but little information is available on its role in non-small cell lung cancer (NSCLC). Here we show that ID1 is induced by nicotinic acetylcholine receptor (nAChR) and epidermal growth factor receptor (EGFR) signaling in a panel of NSCLC cell lines and primary cells from the lung. ID1 induction was Src dependent and mediated through the α7 subunit of nAChR; transfection of K-Ras or EGFR to primary cells induced ID1. ID1 depletion prevented nicotine- and EGF-induced proliferation, migration, and invasion of NSCLC cells and angiogenic tubule formation of human microvascular endothelial cells from lungs (HMEC-Ls). ID1 could induce the expression of mesenchymal markers such as vimentin and fibronectin by downregulating ZBP-89, a zinc finger repressor protein. ID1 levels were elevated in tumors from mice that were exposed to nicotine. Further, human lung tissue microarrays (TMAs) showed elevated levels of ID1 in NSCLC samples, with maximal levels in metastatic lung cancers. Quantitative reverse transcription-PCR (RT-PCR) performed on patient lung tumors showed that ID1 levels were elevated in advanced stages of NSCLC and correlated with elevated expression of vimentin and fibronectin, irrespective of smoking history.