Chemosensitivity Of Hepatocellular Carcinoma Cells Research Articles

MiR-130b-3p Suppress the Migration, Proliferation and Chemosensitization of Hepatocellular Carcinoma Cells

Hepatocellular carcinoma (HCC) is one of the most commonly diagnosed cancers globally, yet its pathogenesis remains incompletely understood. Among the various mechanisms contributing to HCC development, small RNAs, such as microRNAs (miRNAs), play a significant role. miRNAs are non-coding RNAs, typically 20-30 nucleotides long, that regulate gene transcription by binding to RNAs, affecting downstream signaling pathways. One such miRNA, hsa-miR-130b-3p, has been associated with cancer development, including HCC, although the full extent of its involvement remains unclear. This study aimed to explore the link between hsa-miR-130b-3p and HCC using bioinformatics analyses and in vitro assays. Publicly available databases were utilized for expression profiling, mRNA and lncRNA target prediction, pathway enrichment, and methylation analysis. In vitro experiments were conducted using a hsa-miR-130b-3p inhibitor in HepG2 cells to assess its effects on proliferation, migration, and oxaliplatin sensitivity. Our findings show that hsa-miR-130b-3p is upregulated in multiple cancers, including HCC, targeting cancer-related genes and interacting with various lncRNAs. Inhibition of hsa-miR-130b-3p reduced cancer cell proliferation and migration, while enhancing drug sensitivity to oxaliplatin. These results suggest that hsa-miR-130b-3p may play a role in HCC pathogenesis, but further studies are required to fully understand its mechanisms.

RNA-binding protein ZCCHC4 promotes human cancer chemoresistance by disrupting DNA-damage-induced apoptosis

RNA-binding proteins (RBPs) play important roles in cancer development and treatment. However, the tumor-promoting RBPs and their partners, which may potentially serve as the cancer therapeutic targets, need to be further identified. Here, we report that zinc finger CCHC domain-containing protein 4 (ZCCHC4) is of aberrantly high expression in multiple human cancer tissues and is associated with poor prognosis and chemoresistance in patients of hepatocellular carcinoma (HCC), pancreatic cancer and colon cancer. ZCCHC4 promotes chemoresistance of HCC cells to DNA-damage agent (DDA) both in vitro and in vivo. HCC cell deficiency of ZCCHC4 reduces tumor growth in vivo and intratumoral interference of ZCCHC4 expression obviously enhances the DDA-induced antitumor effect. Mechanistically, ZCCHC4 inhibits DNA-damage-induced apoptosis in HCC cells by interacting with a new long noncoding RNA (lncRNA) AL133467.2 to hamper its pro-apoptotic function. Also, ZCCHC4 blocks the interaction between AL133467.2 and γH2AX upon DDA treatment to inhibit apoptotic signaling and promote chemoresistance to DDAs. Knockout of ZCCHC4 promotes AL133467.2 and γH2AX interaction for enhancing chemosensitivity in HCC cells. Together, our study identifies ZCCHC4 as a new predictor of cancer poor prognosis and a potential target for improving chemotherapy effects, providing mechanistic insights to the roles of RBPs and their partners in cancer progression and chemoresistance.

TRIM62 silencing represses the proliferation and invasion and increases the chemosensitivity of hepatocellular carcinoma cells by affecting the NF-κB pathway

Tripartite interaction motif 62 (TRIM62), which is associated with the tumorigenic process, has been found to be aberrantly expressed in numerous cancers. However, the relationship between TRIM62 and hepatocellular carcinoma (HCC) has not been explored. In this work, the expression, function, and potential mechanism of TRIM62 in HCC were investigated. High TRIM62 levels were exhibited in HCC tissue, which contributed to a reduced overall survival. Loss-of-function experiments showed that TRIM62-silencing HCC cells proliferated more slowly, had reduced invasive ability and epithelial–mesenchymal transition, and were more sensitive to chemotherapeutic drug sorafenib. TRIM62 silencing resulted in the suppression of nuclear factor-kappa B (NF-κB), whereas the forced expression of TRIM62 enhanced NF-κB activation. The reduction of NF-κB could reverse TRIM62-overexpression-induced oncogenic effects in HCC cells. Importantly, TRIM62-silencing HCC cells had reduced tumorigenicity in nude mice. In summary, our data indicate that TRIM62 is highly expressed in HCC and acts as a potential tumor promoter. This work confirms that TRIM62 suppression displays remarkable tumor suppressive effects in HCC by affecting NF-κB activation.

Gut microbiota enhances the chemosensitivity of hepatocellular carcinoma to 5-fluorouracil in vivo by increasing curcumin bioavailability.

5-Fluorouracil (5-Fu) is efficient for hepatocellular carcinoma (HCC) treatment, but fast-emerging resistance limits its usage. Curcumin is being investigated for its potential chemosensitivity, but its low oral bioavailability hinders its chemosensitivity effect in vivo. Gut microbiota modulation is considered to contribute to its bioactivities in vivo. In the current study, we demonstrate that curcumin can enhance 5-Fu chemosensitivity in HCC cells in vitro, increase the apoptosis rate, arrest the cell cycle at G2/M phase, and block the PI3k/AKT/mTOR signalling pathway by inhibiting the phosphorylation of PI3K and its downstream protein kinases. Curcumin also remarkably sensitized H22 cells to 5-Fu, allowing it to inhibit tumour growth in vivo. 16S rDNA sequencing suggests that curcumin in combination with 5-Fu significantly alters the gut microbiota composition based on alpha and beta diversity analysis compared to drug treatment alone. Gut microbiota depletion abolished curcumin's chemosensitivity effect in vivo. A pharmacodynamics study suggested that the gut microbiota increased the oral bioavailability of curcumin (AUC(0-t) 15.24 ± 0.77 μM/h [wt] vs. 3.04 ± 0.18 μM/h [gut microbiota depleted]). In conclusion, curcumin can increase the chemosensitivity of HCC to 5-Fu in vitro and in vivo, and gut microbiota plays a key role in its effect in vivo.

Bcl-2/BCL2L12 mediated apoptosis and cell cycle arrest induced by Kaempferol through the suppression of PI3K/AKT signaling pathway in Hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a highly aggressive and third leading cancer-related death. PI3k/AKT and p53 signaling pathways play a vital role and regulate cellular proliferation, migration, cell cycle, apoptosis, and autophagy during cancer conditions. BCL2L12 is a bcl-2 family protein and encoded by the BCL2L12 gene, which is involved in the execution phase of apoptosis. However, the biological function of PI3K/AKT/Bcl-2 mediated BCL2L12, and its molecular mechanism in HCC is largely unknown. Herein, we investigated the effect of Kaempferol, on PI3K/AKT/Bcl-2/BCL2L12 expressions in HCC cells. The expression level of PI3K/AKT/Bcl-2/BCL2L12, and its target genes in polyphenolic flavonoid Kaempferol treated HCC cells analyzed by Quantitative Real-Time PCR and Western blotting. Subsequently, the effect of Kaempferol in HCC chemosensitivity, cell proliferation, migration, cell cycle, and apoptosis were analyzed using AO/EtBr staining, ROS staining, mitochondrial membrane potential assay, wound healing assay, Transwell migration assay, MTT assay, and PI Staining. We found that the downregulation of PI3-K, AKT, LC3A/B, MMP9, Bcl-2, and BCL2L12 and upregulation of PTEN, p53, p21, and caspase 3 in Kaempferol treated HCC cells. Subsequently, we observed that Kaempferol effectively inhibits cellular proliferation, migration and enhances apoptosis, cell cycle arrest, autophagy, and 5-Fluorouracil mediated chemosensitivity in HCC cells. Furthermore, Kaempferol has dominant role against HCC and inhibits 50-60% of cells after 24h treatment with 30μM in HepG2 and 40μM in Huh7 cells. Therefore, Kaempferol plays a promising role in cancer therapeutics by inhibiting PI3K/AKT/Bcl-2 mediated BCL2L12 expression in HCC.

Saikosaponin-d Inhibits the Hepatoma Cells and Enhances Chemosensitivity Through SENP5-Dependent Inhibition of Gli1 SUMOylation Under Hypoxia.

Chemosensitivity is one of the key factors affecting the therapeutic effect on cancer, but the clinical application of corresponding drugs is rare. Hypoxia, a common feature of many solid tumors, including hepatocellular carcinoma (HCC), has been associated with resistance to chemotherapy in part through the activation of the Sonic Hedgehog (SHh) pathway. Hypoxia has also been associated with the increased SUMOylation of multiple proteins, including GLI family proteins, which are key mediators of SHh signaling, and has become a promising target to develop drug-resistant drugs for cancer treatment. However, there are few target drugs to abrogate chemotherapy resistance. Saikosaponin-d (Ssd), one of the main bioactive components of Radix bupleuri, has been reported to exert multiple biological effects, including anticancer activity. Here, we first found that Ssd inhibits the malignant phenotype of HCC cells while increasing their sensitivity to the herpes simplex virus thymidine kinase/ganciclovir (HSVtk/GCV) drug system under hypoxia in vitro and in vivo. Furthermore, we had explored that GLI family activation and extensive protein SUMOylation were characteristics of HCC cells, and hypoxia could activate the SHh pathway and promote epithelial-mesenchymal transition (EMT), invasion, and chemosensitivity in HCC cells. SUMOylation is required for hypoxia-dependent activation of GLI proteins. Finally, we found that Ssd could reverse the effects promoted by hypoxia, specifically active sentrin/small ubiquitin-like modifier (SUMO)-specific protease 5 (SENP5), a SUMO-specific protease, in a time- and dose-dependent manner while inhibiting the expression of SUMO1 and GLI proteins. Together, these findings confirm the important role of Ssd in the chemoresistance of liver cancer, provide some data support for further understanding the molecular mechanisms of Ssd inhibition of malignant transformation of HCC cells, and provide a new perspective for the application of traditional Chinese medicine in the chemical resistance of liver cancer.

Retraction Note: Antisense oligonucleotides targeting midkine induced apoptosis and increased chemosensitivity in hepatocellular carcinoma cells.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

MiR-126 enhances cisplatin chemosensitivity in hepatocellular carcinoma cells by targeting IRS1

Purpose : To investigate the potential role of miR-126 in regulating the proliferation and cisplatin chemosensitivity of human hepatocellular carcinoma (HCC) cells. Methods : The expression of miR-126 was evaluated using clinical HCC specimens. MiR-126-mediated downregulation of Insulin Receptor Substrate 1 (IRS1) was determined by qRT-PCR, western blot and luciferase reporter assay. Cell Counting Kit-8 (CCK8) and colony formation assays were performed to examine the proliferation of HCC cells. Results : Decreased expression of miR126 was found in HCC tumors and was correlated with poor survival in HCC patients. In HCC cells, miR-126 targeted IRS1 for downregulation, through which miR- 126 suppressed the growth of HCC cells and desensitized HCC cells to cisplatin treatment. Conclusion : MiR-126a impairs the proliferation and cisplatin chemoresistance of HCC cells by targeting IRS1. Keywords : miR-126, IRS1, HCC, cisplatin, chemosensitivity

Chemosensitization of hepatocellular carcinoma cells to sorafenib by β-caryophyllene oxide-induced inhibition of ABC export pumps.

Several ATP-binding cassette (ABC) proteins reduce intracellular concentrations of antitumor drugs and hence weaken the response of cancer cells to chemotherapy. Accordingly, the inhibition of these export pumps constitutes a promising strategy to chemosensitize highly chemoresistant tumors, such as hepatocellular carcinoma (HCC). Here, we have investigated the ability of β-caryophyllene oxide (CRYO), a naturally occurring sesquiterpene component of many essential oils, to inhibit, at non-toxic doses, ABC pumps and improve the response of HCC cells to sorafenib. First, we have obtained a clonal subline (Alexander/R) derived from human hepatoma cells with enhanced multidrug resistance (MDR) associated to up-regulation (mRNA and protein) of MRP1 and MRP2. Analysis of fluorescent substrates export (flow cytometry) revealed that CRYO did not affect the efflux of fluorescein (MRP3, MRP4 and MRP5) but inhibited that of rhodamine 123 (MDR1) and calcein (MRP1 and MRP2). This ability was higher for CRYO than for other sesquiterpenes assayed. CRYO also inhibited sorafenib efflux, increased its intracellular accumulation (HPLC-MS/MS) and enhanced its cytotoxic response (MTT). For comparison, the effect of known ABC pumps inhibitors was also determined. They induced strong (diclofenac on MRPs), modest (verapamil on MDR1) or null (fumitremorgin C on BCRP) effect on sorafenib efflux and cytotoxicity. In the mouse xenograft model, the response to sorafenib treatment of subcutaneous tumors generated by mouse hepatoma Hepa 1-6/R cells, with marked MDR phenotype, was significantly enhanced by CRYO co-administration. In conclusion, at non-toxic dose, CRYO is able to chemosensitizating liver cancer cells to sorafenib by favoring its intracellular accumulation.

Bile salt (glycochenodeoxycholate acid) induces cell survival and chemoresistance in hepatocellular carcinoma.

Glycochenodeoxycholate acid (GCDA) is a toxic component in bile salts. It plays an important role in the development and progression of liver cancer. In this study, we investigated the underlying mechanism of GCDA in hepatocarcinogenesis and chemotherapy resistance. Cell proliferation was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and clonality by Ki-67 and colony-formation assay. Apoptosis was examined by flow cytometry. Real-time polymerase chain reaction (PCR) and western blot analysis were used to measure messenger RNA and protein levels, respectively. Short hairpin RNA was used to silence signal transducer and activator of transcription 3 (Stat3) expression. Bile salts (GCDA) promoted the proliferation of hepatocellular carcinoma (HCC) cells (HepG2 and QGY-7703), and GCDA treatment reduced the chemosensitivity of 5-fluorouracil (5FU) in HepG2 and QGY-7703 cells. GCDA upregulated the expression of antiapoptosis proteins Mcl-1/Survivin/Bcl-2. GCDA had no discernible effect on basal protein level or subcellular localization of phosphorylated Stat3. 5FU increased the apoptosis of HepG2 cells with silenced Stat3 expression, but GCDA-induced chemoresistance was not reversed. GCDA-reduced HCC cell chemosensitivity may occur by upregulating antiapoptosis proteins Mcl-1/Survivin/Bcl-2. Stat3 may be a target for enhancing the chemosensitivity of hepatocellular carcinoma cells, but GCDA-induced chemoresistance is independent of Stat3.

SIRT6 Depletion Sensitizes Human Hepatoma Cells to Chemotherapeutics by Downregulating MDR1 Expression.

Multidrug resistance (MDR) due to overexpression of MDR1 is a major obstacle that hinders the treatment of hepatocellular carcinoma (HCC). In this study, we explored the function and underlying molecular mechanism of SIRT6 in MDR of HCC. Chemotherapeutic agents (doxorubicin, cisplatin, and sorafenib) treatment increased SIRT6 mRNA and protein level in two HCC cell lines in a dose-dependent manner. SIRT6 depletion resulted in decreased cell viability and increased apoptosis in HCC cells treated with chemotherapeutic agents. Mechanistically, SIRT6 depletion reduced MDR1 transcription by targeting its promoter in HCC cells treated with chemotherapeutic agents. Consistently, the protein level of MDR1 was also reduced in SIRT6-depleted HCC cells. Further studies indicated that SIRT6 depletion may suppress CCAAT/enhancer binding protein β (C/EBPβ), to act as a transcriptional activator of MDR1 in HCC cells treated with chemotherapeutic agents. Importantly, forced expression of MDR1 could attenuate the apoptosis induced by chemotherapeutic agents in SIRT6-depleted cells. Taken together, these results indicated SIRT6 depletion enhanced chemosensitivity of human hepatoma cells by downregulating MDR1 expression through suppressing C/EBPβ. SIRT6 may serve as a novel target to enhance chemosensitivity in HCC cells.

Puerarin increases the chemosensitivity of hepatocellular carcinoma cells.

The present study investigated the effect of puerarin (Pu) on the sensitivity of HepG2 human hepatocellular carcinoma (HCC) cells to chemotherapeutic drugs to determine the possible mechanism. HepG2 cells were treated with different concentrations of Pu and cisplatin (CDDP), alone or in combination. MTT assay was used to determine the inhibitory effects of the different drugs on HepG2 cells. Cell morphology was observed by inverted microscopy. The expression of B-cell lymphoma 2 (Bcl-2) and Bax protein was measured by western blot analysis. Pu and CDDP, alone or in combination, inhibited the proliferation of HepG2 cells. The inhibitory effect of CDDP combined with Pu on HepG2 cells was significantly higher than that of the single drug treatments (p<0.01). In addition, compared with the single drug groups, cellular morphology was significantly altered and the apoptotic rate of cells and the expression of Bax protein were significantly increased (p<0.01). However, the expression of Bcl-2 protein was significantly decreased (p<0.01) in the combined drug group. In conclusion, Pu can increase the sensitivity of HCC to chemotherapeutic drugs, enhance the inhibitory effect of chemotherapeutic drugs on cell proliferation and synergistically induce apoptosis of HepG2 cells. The mechanism is likely related to the upregulation of Bax protein and the downregulation of Bcl-2 protein.

USP22 knockdown enhanced chemosensitivity of hepatocellular carcinoma cells to 5-Fu by up-regulation of Smad4 and suppression of Akt.

USP22, a member of the deubiquitinases (DUBs) family, is known to be a key subunit of the human Spt-Ada-Gcn5 acetyltransferase (hSAGA) transcriptional cofactor complex. Within hSAGA, USP22 removes ubiquitin from histone proteins, thus regulating the transcription and expression of downstream genes. USP22 plays important roles in many cancers; however, its effect and the mechanism underlying HCC chemoresistance remain unclear. In the present study, we found that USP22 was highly expressed in chemoresistant HCC tissues and cells and was correlated with the prognosis of HCC patients who received chemotherapy. Silencing USP22 in chemoresistant HCC Bel/Fu cells dramatically inhibited proliferation, migration, invasion and epithelial-mesenchymal transition in vitro; suppressed tumorigenic and metastatic capacities in vivo; and inhibited drug resistance-related proteins (MDR1, LRP, MRP1). Mechanistically, we found that USP22 knockdown exerts its function through down-regulating PI3K and activating Smad4, which inhibited phosphorylation of Akt. Silencing Smad4 blocked USP22 knockdown-induced Akt inhibition in Bel/Fu cells. Our results, for the first time, provide evidence that USP22 plays a critical role in the development of chemoresistant HCC cells and that high USP22 expression serves as a molecular marker for the prognosis of HCC patients who undergo chemotherapy.

Gambogenic acid induces proteasomal degradation of CIP2A and sensitizes hepatocellular carcinoma to anticancer agents

Cancerous inhibitor of protein phosphatase2A (CIP2A) is an oncoprotein that is overexpressed in many human malignancies. It regulates phosphorylated AKT and stabilizes c‑Myc in cell proliferation and tumor formation, suggesting that CIP2A plays an essential role in the development of cancer. In the present study, we report that a natural compound, gambogenic acid(GEA), induced the degradation of CIP2A via the ubiquitin‑proteasome pathway. Interestingly, the combination of GEA and proteasome inhibitors potentiated the accumulation of ubiquitinated CIP2A and aggresome formation. In addition, GEA exhibited an inhibitory effect on cell proliferation and CIP2A‑downstream signaling molecules (c‑Myc and pAKT). Furthermore, GEA and CIP2A silencing enhanced the chemosensitivity of hepatocellular carcinoma cells to anticancer agents, suggesting that a combination of a CIP2A inhibitor and anticancer agents could be a valuable clinical therapeutic strategy. These results indicate that GEA is a CIP2A inhibitor that interferes with the ubiquitination and destabilization of CIP2A, providing a promising strategy to enhance the combinational therapy for hepatocellular carcinoma.

Mus81 knockdown improves chemosensitivity of hepatocellular carcinoma cells by inducing S-phase arrest and promoting apoptosis through CHK1 pathway.

As a critical endonuclease in DNA repair, Mus81 is traditionally regarded as a tumor suppressor, but recently correlated with the sensitivity of mitomycin C and 5-fluorouracil in colon cancer and breast cancer cells. However, its role in chemosensitivity of other human malignancies still remains unknown. This study therefore aims to investigate the effects of Mus81 knockdown on the chemosensitivity of hepatocellular carcinoma (HCC), a usually chemorefractory tumor, and explore the underlying mechanisms. Mus81 expression in HepG2 and Bel-7402 HCC cell lines was depleted by lentivirus-mediated short hairpin RNA and the elevated sensitivity of these Mus81-inhibited HCC cells to therapeutic agents, especially to epirubicin (EPI), was evidenced by MTT assay and an HCC chemotherapy mouse model. Flow cytometric analysis also showed that Mus81 knockdown lead to an obvious S-phase arrest and an elevated apoptosis in EPI-treated HepG2 and Bel-7402 cells, which could be rescued by CHK1 inhibition. The activation of CHK1/CDC25A/CDK2 pathway was also demonstrated in Mus81-inhibited HepG2 cells and xenograft mouse tumors under EPI treatment. Meanwhile, the apoptosis of HepG2 cells in response to EPI was remarkably promoted by Mus81 knockdown through activating p53/Bax/Caspase-3 pathway under the controlling of CHK1. In addition, CHK2 inhibition slightly raised CHK1 activity, thereby enhancing the S-phase arrest and apoptosis induced by EPI in Mus81-suppressed HCC cells. In conclusion, Mus81 knockdown improves the chemosensitivity of HCC cells by inducing S-phase arrest and promoting apoptosis through CHK1 pathway, suggesting Mus81 as a novel therapeutic target for HCC.

The effects of Livin shRNA on the response to cisplatin in HepG2 cells.

Hepatocellular carcinoma is a lethal malignancy with poor prognosis, partially due to tumor metastasis, recurrence and resistance to chemo- or radio-therapy. Cisplatin can inhibit cancer cell DNA replication, and is widely used in the clinical treatment of tumors. The present study aimed to generate eukaryotic expression vectors for Livin shRNA and to examine the effects of Livin shRNA on the chemosensitivity of HepG2 hepatocellular carcinoma cells. Eukaryotic expression vectors for Livin shRNA (pSD11-U6/Neo/GFP/Livin) were designed and constructed. The HepG2 hepatocellular carcinoma cell line was transfected with this vector using the liposome method. The expression levels of Livin mRNA and protein were measured by quantitative polymerase chain reaction and western blot analysis. The rate of cell growth inhibition was measured using MTT assay following treatment of the cells with cisplatin (2.0 mg/l). DNA sequencing confirmed that the construction of the eukaryotic expression vector for Livin shRNA had been successful. Transfection of these vectors into HepG2 cells led to a significant reduction in the expression levels of Livin mRNA and protein (P<0.05). Cisplatin treatment was associated with significantly higher rates of cell growth inhibition in HepG2 cells transfected with Livin shRNA compared with those that were not transfected (P<0.05). The vectors constructed in the present study produced effective inhibition of the Livin gene in HepG2 cells and increased the chemosensitivity of hepatocellular carcinoma cells.

Downregulation of Vascular Endothelial Growth Factor Enhances Chemosensitivity by Induction of Apoptosis in Hepatocellular Carcinoma Cells.

Hepatocellular carcinoma (HCC), one of the most common cancers worldwide, is resistant to anticancer drugs. Angiogenesis is a major cause of tumor resistance to chemotherapy, and vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis. The purpose of this study is to investigate the impact of small-interfering RNA targeting VEGF gene (VEGF-siRNA) on chemosensitivity of HCC cells in vitro. In this experimental study, transfection was performed on Hep3B cells. After transfection with siRNAs, VEGF mRNA and protein levels were examined. Cell proliferation, apoptosis and anti-apoptotic gene expression were also analyzed after treatment with VEGF-siRNA in combination with doxorubicin in Hep3B cells. Transfection of VEGF-siRNA into Hep3B cells significantly reduced the expression of VEGF at both mRNA and protein levels. Combination therapy with VEGF-siRNA and doxorubicin more effectively suppressed cell proliferation and induced apoptosis than the respective monotherapies. This could be explained by the significant downregulation of B-cell lymphoma 2 (BCL-2) and SURVIVIN. VEGF-siRNA enhanced the chemosensitivity of doxorubicin in Hep3B cells at least in part by suppressing the expression of anti-apoptotic genes. Therefore, the downregulation of VEGF by siRNA combined with doxorubicin treatment has been shown to yield promising results for eradicating HCC cells.

Downregulation of Kinesin spindle protein inhibits proliferation, induces apoptosis and increases chemosensitivity in hepatocellular carcinoma cells.

Background: Kinesin spindle protein (KSP) plays a critical role in mitosis. Inhibition of KSP function leads to cell cycle arrest at mitosis and ultimately to cell death. The aim of this study was to suppress KSP expression by specific small-interfering RNA (siRNA) in Hep3B cells and evaluate its anti-tumor activity. Methods: Three siRNA targeting KSP (KSP-siRNA #1-3) and one mismatched-siRNA (Cont-siRNA) were transfected into cells. Subsequently, KSP mRNA and protein levels, cell proliferation, and apoptosis were examined in both Hep3B cells and THLE-3 cells. In addition, the chemosensitivity of KSP-siRNA-treated Hep3B cells with doxorubicin was also investigated using cell proliferation and clonogenic survival assays. Results: The expression of endogenous KSP at both mRNA and protein levels in Hep3B cells was higher than in THLE-3 cells. In Hep3B cells, KSP-siRNA #2 showed a further downregulation of KSP as compared to KSP-siRNA #1 or KSP-siRNA #3. It also exhibited greater suppression of cell proliferation and induction of apoptosis than KSP-siRNA #1 or KSP-siRNA #3; this could be explained by the significant downregulation of cyclin D1, Bcl-2, and survivin. In contrast, KSP-siRNAs had no or lower effects on KSP expression, cell proliferation and apoptosis in THLE-3 cells. We also noticed that KSP-siRNA transfection could increase chemosensitivity to doxorubicin in Hep3B cells, even at low doses compared to control. Conclusion: Reducing the expression level of KSP, combined with drug treatment, yields promising results for eradicating hepatocellular carcinoma (HCC) cells in vitro. This study opens a new direction for liver cancer treatment.

Abstract 3865: ATOH8 depletion can reprogram noncancer stem cells into cancer stem cells

Abstract Introduction: The development of hepatocellular carcinoma (HCC), one of the most lethal of human malignancies, is caused by the accumulation of multiple genetic and epigenetic alterations. Recent advances in cancer stem cell (CSC) study have associated the poor prognosis of cancer with CSC. ATOH8 is a nucleus factor with an obvious structural similarity to the Drosophila proneural gene atonal. The aim of this study is to investigated the role of ATOH8 in CSC and its therapeutic potentials for HCC treatment. Experimental procedures: The clinical significance of ATOH8 in a cohort of 242 HCC cases was assessed by clinical correlation and Kaplan-Meier survival analyses. ATOH8-overexpressing and scliencing cell model was generated by Lentivirus system to detect its functional roles in HCC both in vivo and in vitro. iPS technology is used to analyze effects of ATOH8 on CSCs. Result: Downregulation of ATOH8 was detected in over 40% of 242 pairs primary HCC cases, which was significantly associated with disease free survival (P=0.031), high level of AFP (P=0.03) and diferentiation (P=0.01). Functional studies demonstrate the tumor suppressive role of ATOH8 in HCC, including the inhibition of cell growth, cell proliferation, tumor formation in SCID mice and cell motility when ATOH8 was introduced into HCC cells. Further study finds that ATOH8 depletion can enhance the stemness of HCC including the tumorigenicity and abilities for self-renewal, differentiation and chemo-resistance by repressing the transcription of stemness-related genes such as OCT4, NANOG, SOX2, AFP, and HCC cancer stem cell (CSC) surface markers such as CD24 and CD133. One interesting finding in this study is that knockdown of ATOH8 could increase CD133+ cell population in QSG7701 and BEL7402 cells. CD133+ cells induced by ATOH8 depletion were flow-sorted and their CSC property was characterized. The results found that flow-sorted CD133+ cells induced by ATOH8 depletion possessed most characteristics of CSC including the capacity to self-renew, differentiation, sustained proliferation and chemoresistance. In addition, ATOH8 depletion could enhance the frequency of pluripotent stem cells (iPSC) generation induced by 4 factors (OCT4, Sox2, Klf4 and cMyc). All these data strongly suggest that a non-CSC could be reprogrammed into a CSC under some circumstance such as downregulation of ATOH8. Conclusion: This study demonstrates that ATOH8 plays an important role in HCC development, and provides a potential new HCC therapeutic approach that ATOH8 could increase the chemosensitivity of HCC cells to chemotherapeutics as demonstrated in this study. Citation Format: Yangyang Song, Xin-Yuan Guan. ATOH8 depletion can reprogram noncancer stem cells into cancer stem cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3865. doi:10.1158/1538-7445.AM2014-3865

Knockdown of mutated H-Ras V12 expression induces chemosensitivity of hepatocellular carcinoma cells to cisplatin treatment in vitro and in nude mouse xenografts.

Ras mutations contribute to human cancer development. The present study assessed the Ras V12 mutation in hepatocellular carcinoma (HCC) cells and the role of its silencing invitro and in nude mouse xenografts. HCC BEL7402 cells expressed mutations of V12 (Val/Gly) and wild-type H-Ras, whereas SMMC7721 cells only expressed wild-type H-Ras. The shRNA constructs specifically silenced mutated H-Ras expression in BEL7402 cells, but did not affect wild-type Ras expression in SMMC7721 cells. Silencing of mutated H-Ras expression reduced BEL7402 cell viability, induced apoptosis and arrested cells at the G0/G1phase of the cell cycle. Expression of phospho-Akt was also significantly decreased, while several apoptotic proteins were also activated. Furthermore, sensitivity of stably H1-shRNA and H2-shRNA transfected BEL7402 cells to cisplatin treatment was increased by 7.19-and 5.39-fold, respectively, compared to that in the negative control cells, and apoptosis-related gene expression was also altered. Intraperitoneal administration of cisplatin led to a substantial reduction in HCC xenograft growth by 81 and 77% in the H1-shRNA and H2-shRNA transfected tumor xenografts, respectively, compared to a 37% reduction in mice bearing negative control tumor cells. These data demonstrate that knockdown of mutated H-Ras V12 expression induced chemosensitivity of HCC cells to cisplatin treatment invitro and invivo.