CIZ1 knockdown suppresses the proliferation of bladder cancer cells by inducing apoptosis

CIZ1 aggravates gastric cancer progression via mediating FBXL19-AS1 and miR-339-3p

Gastric cancer (GC) remains a prevalent malignancy with high morbidity and mortality. CDKN1A interacting zinc finger protein 1 (CIZ1) has been demonstrated to have oncogenic functions in the development of cancers. We detected CIZ1 expression via quantitative real-time PCR (RT-qPCR). The protein level of CIZ1 was measured through Western blot. We noticed that CIZ1 expression was markedly enhanced in GC cells. Furthermore, functional experiments including colony formation assay, EdU staining assay, transwell assay, TUNEL staining assay and flow cytometry analysis uncovered that CIZ1 silencing attenuated cell malignant phenotypes in GC. Through bioinformatics tools and mechanism assays, we explored the up-stream mechanism of CIZ1 and determined that CIZ1 was modulated by FBXL19 antisense RNA 1 (FBXL19-AS1) and microRNA-339-3p (miR-339-3p). Additionally, miR-339-3p exerted a negative role on GC development in vitro, and FBXL19-AS1 depletion also had the inhibitory impacts on the progression of GC in vitro. Eventually, the finding that CIZ1 overexpression reversed the effects of FBXL19-AS1 silencing on GC development was validated by rescue assays. In a word, CIZ1 functioned as a tumor promoter in GC, indicating that CIZ1 might be a promising target for GC treatment.

Epigenetic instability caused by absence of CIZ1 drives transformation during quiescence cycles

BACKGROUND

Cip1-interacting zinc finger protein 1 (CIZ1) forms RNA-dependent protein assemblies that stabilise epigenetic state, notable at the inactive X chromosome in females. CIZ1 has been linked with a range of human cancers and in mice genetic deletion of CIZ1 manifests as hyperproliferative lymphoid lineages in females. This suggests that its role in maintenance of epigenetic stability is linked with disease.

RESULTS

Here, we show that male and female CIZ1-null primary murine fibroblasts have reduced H4K20me1 and that this compromises nuclear condensation on entry to quiescence. Global transcriptional repression remains intact in condensation-deficient CIZ1-null cells; however, a subset of genes linked with chromatin condensation and homology-directed DNA repair are perturbed. Failure to condense is phenotypically mimicked by manipulation of the H4K20me1 methyltransferase, SET8, in WT cells and partially reverted in CIZ1-null cells upon re-expression of CIZ1. Crucially, during exit from quiescence, nuclear decondensation remains active, so that repeated entry and exit cycles give rise to expanded nuclei susceptible to mechanical stress, DNA damage checkpoint activation, and downstream emergence of transformed proliferative colonies.

CONCLUSIONS

Our results demonstrate a role for CIZ1 in chromatin condensation on entry to quiescence and explore the consequences of this defect in CIZ1-null cells. Together, the data show that CIZ1's protection of the epigenome guards against genome instability during quiescence cycles. This identifies loss of CIZ1 as a potentially devastating vulnerability in cells that undergo cycles of quiescence entry and exit.

KLF16 Downregulates the Expression of Tumor Suppressor Gene TGFBR3 to Promote Bladder Cancer Proliferation and Migration

Introduction

Krüppel-like factors (KLFs), which comprise 17 family members, exert important functions during the development of cancer. The role of KLF16 seems controversial in carcinogenesis because both tumor suppressive and promoting effects have been reported.

Methods

The expression level of KLF16 was analyzed based on public data sets from The Cancer Genome Atlas (TCGA) and evaluated by immunohistochemical (IHC) staining. CCK8 assay, colony formation analysis, transwell assays and the PI/Annexin V-APC assay kit were performed to detect cell growth, colony formation, cell migration and apoptosis of BC cells. Xenograft tumorigenesis assay was performed to detect the KLF16 expression on BC growth in vivo. Dual-luciferase reporter assay and chromatin immunoprecipitation (ChIP)-qPCR assay were performed to analyze the interaction between KLF16 and its target.

Results

In this study, we explored the role of KLF16 in bladder cancer (BC). We demonstrated that KLF16 was overexpressed in human BC tissues. The high expression of KLF16 was a potential predictor of a poor prognosis in patients with BC. Interference with KLF16 expression in 563 cells, having relatively higher levels of KLF16, repressed cell proliferation and migration. In contrast, upregulation of KLF16 in T24 cells enhanced cellular function, including cell growth and migration. KLF16 also suppressed the apoptosis of BC cells. Additionally, KLF16 inhibited the expression of the TGF-type III receptor (TGFBR3) by binding to its promoter sequence and reducing transcriptional activity. There was a negative correlation between KLF16 and TGFBR3 in human BC tissues. Furthermore, TGFBR3 was revealed to be a negative regulator of BC cell proliferation and migration. KLF16 also supported BC tumorigenesis by downregulating TGFBR3 expression in vivo.

Discussion

These results suggested that KLF16 acts as an oncogene in BC through transcriptional inactivation of TGFBR3. This study provides evidence that targeting the KLF16/TGFBR3 axis may be beneficial for BC patients.

Akt1 and dCIZ1 promote cell survival from apoptotic caspase activation during regeneration and oncogenic overgrowth

Apoptosis is an ancient and evolutionarily conserved cell suicide program. During apoptosis, executioner caspase enzyme activation has been considered a point of no return. However, emerging evidence suggests that some cells can survive caspase activation following exposure to apoptosis-inducing stresses, raising questions as to the physiological significance and underlying molecular mechanisms of this unexpected phenomenon. Here, we show that, following severe tissue injury, Drosophila wing disc cells that survive executioner caspase activation contribute to tissue regeneration. Through RNAi screening, we identify akt1 and a previously uncharacterized Drosophila gene CG8108, which is homologous to the human gene CIZ1, as essential for survival from the executioner caspase activation. We also show that cells expressing activated oncogenes experience apoptotic caspase activation, and that Akt1 and dCIZ1 are required for their survival and overgrowth. Thus, survival following executioner caspase activation is a normal tissue repair mechanism usurped to promote oncogene-driven overgrowth.

Dihydroartemisinin inhibits the tumorigenesis and metastasis of breast cancer via downregulating CIZ1 expression associated with TGF-β1 signaling

AIMS

Dihydroartemisinin (DHA) is currently considered as the promising cancer therapeutic drug. In this study, we aimed to investigate the anti-proliferative and anti-metastasis effects of DHA.

MAIN METHODS

Utilizing breast cancer cells MCF-7, MDA-MB-231 and BT549, cell proliferation, migration and invasion were detected. RT-qPCR was performed to detect CIZ1, TGF-β1 and Snail expression, and the interactions of these related molecules were analyzed by GeneMANIA database. Western blot detected CIZ1, TGF-β1/Smads signaling and Snail expression in DHA-treated cells, in TGFβ1-induced cells with enhanced metastatic capacity, and in cells treated with DHA plus TGFβ1/TGFβ1 inhibitor SD-208.

KEY FINDINGS

Results indicated DHA inhibited breast cancer cell proliferation and migration, with more potent effects compared with that of artemisinin. RT-qPCR and Western blot showed DHA inhibited CIZ1, TGF-β1 and Snail expression, and these molecules were shown to have protein-protein interactions by bioinformatics. Furthermore, TGFβ1-treatment enhanced MCF-7 migration and invasion, and CIZ1, TGF-β1/Smads signaling and snail activities; DHA, SD-208, combination of DHA and SD-208 reversed these conditions, preliminarily proving the cascade regulation between TGF-β1 signaling and CIZ1. MCF-7 xenografts model demonstrated the inhibition of DHA on tumor burden, and its mechanisms and well-tolerance in vivo; combination of DHA and SD-208 tried by us for the first time showed better treatment effects, but possible liver impairment made its use still keep cautious.

SIGNIFICANCE

DHA treatment inhibits the proliferation and metastasis of breast cancer, through suppressing TGF-β1/Smad signaling and CIZ1, suggesting the promising potential of DHA as a well-tolerated antitumor TGF-β1 pathway inhibitor.

The Effects of Orientin on Proliferation and Apoptosis of T24 Human Bladder Carcinoma Cells Occurs Through the Inhibition of Nuclear Factor-kappaB and the Hedgehog Signaling Pathway

Background

Orientin is a flavone isolated from medicinal plants used in traditional Chinese medicine (TCM), which suppresses the growth of cancer cells in vitro. The effects of orientin in bladder cancer cells remains unknown. This study aimed to investigate the effect of orientin on proliferation and apoptosis of T24 human transitional cell bladder carcinoma cells in vitro in the presence of an agonist and an inhibitor of nuclear factor-kappaB (NF-κB).

Material/Methods

T24 cells were cultured and divided into four study groups: an untreated control group; a group treated with 100 μM orientin; a group treated with 100 μM orientin with NF-κB agonist, phorbol 12-myristate 13-acetate (PMA); and a group treated with 100 μM orientin and the NF-κB inhibitor, IκBα. The MTT assay was performed to assess cell viability, and flow cytometry evaluated the cell cycle. The expression of proteins in the Hedgehog signaling pathway and inflammatory cytokines were determined by Western blot and enzyme-linked immunosorbent assay (ELISA).

Results

Orientin inhibited the proliferation of T24 cells, caused cell cycle arrest, reduced cell viability, and inhibited the expression of inflammatory mediators. Treatment of T24 cells with orientin inhibited the expression of NF-κB and components of the Hedgehog signaling pathway, and the NF-κB agonist, PMA, reversed these effects.

Conclusions

Treatment of T24 human bladder carcinoma cells in vitro with orientin inhibited cell proliferation and promoted cell apoptosis by suppressing the Hedgehog signaling pathway and NF-κB.

Knockdown of SLC35F2 Inhibits the Proliferation and Metastasis of Bladder Cancer Cells

Background

Many studies have shown that solute carrier family 35 member F2 (SLC35F2) plays a key role in the biological processes of multiple cancers. However, there have been no reports on the role of SLC35F2 in the occurrence and development of bladder cancer (BC).

Methods

SLC35F2 expression data and clinical and prognostic information from BC patients were obtained from databases. SLC35F2 expression in BC was verified by quantitative real-time PCR (qRT-PCR). The influence of SLC35F2 knockdown on the proliferation, apoptosis, migration and invasion in the 5637 and T24 cell lines was studied, and tumor formation experiments were performed in nude mice. Gene set enrichment analysis (GSEA) was used to predict the pathways and functions of SLC35F2 in BC.

Results

SLC35F2 was highly expressed in BC tissues and was associated with invasiveness and T stage in BC patients. SLC35F2 knockdown can inhibit the proliferation, migration and invasion of BC cells and can promote apoptosis. SLC35F2 knockdown significantly reduced tumorigenesis in nude mice. GSEA showed that BC, pathways in cancer, apoptosis and the P53 signaling pathway were significantly enriched in SLC35F2 high expression phenotype.

Conclusion

SLC35F2 can promote malignant progression and is a potential therapeutic target in BC.