Panel Of Hepatocellular Carcinoma Cell Lines Research Articles

Mechanisms of Sorafenib Resistance in HCC Culture Relate to the Impaired Membrane Expression of Organic Cation Transporter 1 (OCT1).

Sorafenib, an FDA-approved drug for advanced hepatocellular carcinoma (HCC) treatment, encounters resistance in many patients. Deciphering the mechanisms underlying sorafenib resistance is crucial for devising alternative strategies to overcome it. This study aimed to investigate sorafenib resistance mechanisms using a diverse panel of HCC cell lines. HCC cell lines were subjected to continuous sorafenib treatment, and stable cell lines (Huh 7.5 and Huh 7PX) exhibiting sustained growth in its presence were isolated. The investigation of drug resistance mechanisms involved a comparative analysis of drug-targeted signal transduction pathways (EGFR/RAF/MEK/ERK/Cyclin D), sorafenib uptake, and membrane expression of the drug uptake transporter. HCC cell lines (Huh 7.5 and Huh 7PX) with a higher IC50 (10μM) displayed a more frequent development of sorafenib resistance compared to those with a lower IC50 (2-4.8μM), indicating a potential impact of IC50 variation on initial treatment response. Our findings reveal that activated overexpression of Raf1 kinases and impaired sorafenib uptake, mediated by reduced membrane expression of organic cation transporter-1 (OCT1), contribute to sorafenib resistance in HCC cultures. Stable expression of the drug transporter OCT1 through cDNA transfection or adenoviral delivery of OCT1 mRNA increased sorafenib uptake and successfully overcame sorafenib resistance. Additionally, consistent with sorafenib resistance in HCC cultures, cirrhotic liver-associated human HCC tumors often exhibited impaired membrane expression of OCT1 and OCT3. Intrinsic differences among HCC cell clones, affecting sorafenib sensitivity at the expression level of Raf kinases, drug uptake, and OCT1 transporters, were identified. This study underscores the potential of HCC tumor targeted OCT1 expression to enhance sorafenib treatment response.

Abstract 2120: Asparaginases-Treatment potential for the biomarker selected hepatocellular carcinoma (HCC) population

Abstract Asparaginase is a key component of the therapeutic regimen used to treat patients with acute lymphoblastic leukemia (ALL). Calaspargase pegol (Asparlas) is composed of E. coli L-asparaginase and is PEGylated with approximately 5000 Da polyethylene glycol (PEG). Asparlas depletes asparagine (Asn) by deamination into aspartic acid. Asn synthetase (ASNS) is the key enzyme responsible for de novo Asn synthesis. In the absence of Asn in their direct environment, normal cells having adequate ASNS activity can survive with their own Asn supply while cancer cells lacking ASNS activity undergo apoptosis as they depend on extracellular sources of Asn. The ASNS gene has a typical CpG island in its promoter and its methylation status in tumor cells has been reported to be associated with asparaginase sensitivity clinically in T-ALL and in solid tumors preclinically. In this study we have investigated ASNS promoter hypermethylation as a biomarker for Asparlas activity in solid tumors and explored the feasibility of translating these results into the clinic. Analyses of the TCGA datasets indicated that a relatively high fraction of hepatocellular carcinoma (HCC) and gastric cancers are hypermethylated at the ASNS promoter. Testing Asparlas across a panel of HCC cell lines demonstrated that ASNS promoter-hypermethylated cell lines with lowest ASNS mRNA expression are the most responsive to Asparlas treatment in vitro. In vivo efficacy studies in mice bearing human ASNS promoter-hypermethylated xenograft models of HCC and gastric cancer showed that Asparlas treatment inhibited tumor growth in a dose-dependent manner and resulted in tumor rejections at the highest doses. Data from the HCC model was used to build a PK/PD efficacy model to project efficacious concentrations in patients. A panel of HCC PDX models with different levels of ASNS promoter methylation was evaluated to better understand the relationship between this biomarker and response to Asparlas. Treatment with Asparlas resulted in complete depletion of Asn in plasma and a partial depletion of Asn in the tumor for all models tested and strong anti-tumor activity against a model that had high methylation of the ASNS promoter. This activity was lost in models with lesser degrees of methylation indicating a strict threshold of promoter methylation for efficacy. These data confirm and extend previous findings that hypermethylation of the ASNS promoter has a synthetic lethal relationship with Asn-depleting therapies including Asparlas and highlight the need to carefully define the minimum threshold of hypermethylation to select HCC patients who could potentially benefit from Asparlas treatment. Citation Format: Ethika Tyagi, Magdalena Pohorecka, Valérie Duvivier, Aurelie Studeny, Damien Valour, Natacha Moulharat, Hélène Darville, Nicolas Provost, Pierre Barbier Saint Hilaire, Eef Hoeben, Donald Simons. Asparaginases-Treatment potential for the biomarker selected hepatocellular carcinoma (HCC) population [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2120.

Osimertinib is a dual inhibitor of hepatocellular carcinoma and angiogenesis in an EGFR-independent manner, and synergizes with venetoclax.

To investigate the effects of osimertinib on hepatocellular carcinoma (HCC) and angiogenesis, and its combinatory effects with venetoclax in HCC. Viability was assessed by flow cytometry of Annexin V in multiple HCC cell lines after drug treatment. In vitro angiogenesis assay was performed using primary human liver tumor associated endothelial cell (HLTEC). HCC-bearing model was generated by subcutaneous implantation of Hep3B cells to investigate the efficacy of osimertinib alone and its combination with venetoclax. Osimertinib significantly induced apoptosis in a panel of HCC cell lines regardless of EGFR expression level. It inhibited capillary network formation and induced apoptosis in HLTEC. Using HCC xenograft mouse model, we further showed that osimertinib at non-toxic dose inhibited tumor growth by ~ 50% and remarkably decreased blood vessel in tumor. Mechanism studies demonstrated that osimertinib acted on HCC cells in an EGFR-independent manner. It decreased level of VEGF and Mcl-1 in HCC cells via suppressed phosphorylation of eIF4E, thus leading to inhibition of eIF4E-mediated translation. Mcl-1 overexpression reversed pro-apoptotic effect of osimertinib, suggesting an important role of Mcl-1 in osimertinib's action in HCC cells. Of note, the combination of osimertinib and venetoclax achieved approximately complete HCC cell death and tumor growth in mice. We provide pre-clinical evidence that osimertinib is a promising candidate for the treatment of HCC via targeting tumor cells and angiogenesis. The combination of osimertinib and venetoclax is synergistic in inhibiting HCC.

Abstract 2658: ZW251, a novel glypican-3-targeting antibody drug conjugate bearing a topoisomerase 1 inhibitor payload

Abstract Background: Glypican-3 (GPC3) is a cell-surface oncofetal glycoprotein frequently expressed in hepatocellular carcinoma (HCC) with minimal presence in normal adult tissues. ZW251 is an antibody-drug conjugate (ADC) targeting human GPC3, composed of a humanized IgG1 antibody conjugated to a novel camptothecin-based topoisomerase 1 inhibitor, ZD06519, via a maleimide anchor and a glycyl glycyl phenylalanyl glycine (GGFG)-aminomethyl (AM) cleavable linker. Materials and Methods: Extensive functional characterization was performed to assess the mechanism of action and therapeutic potential of the ZW251 ADC. Antibody binding to human and cynomolgus monkey GPC3 was assessed by surface plasmon resonance and flow cytometry. A screen of off-target binding and target specificity was conducted using a membrane proteome array. ZW251 antibody internalization in GPC3-expressing tumor cell lines was assessed by flow cytometry. In vitro ADC cytotoxicity against tumor monolayers and spheroids was assessed in a panel of HCC cell lines. Tumor cell co-culture assays were also performed to assess bystander-mediated cell killing by ZW251. The pharmacokinetic (PK) profile of the ZW251 antibody was assessed in Tg32 mice expressing human FcRn. Anti-tumor activity of ZW251 was investigated in a large panel of cell line-derived xenograft (CDX) and patient-derived xenograft (PDX) mouse models representing a range of GPC3 expression. Results: The ZW251 antibody backbone demonstrated nanomolar binding affinity to both human and cynomolgus monkey GPC3, and strong binding to target-expressing cancer cell lines. Rapid internalization of ZW251 antibody was observed in GPC3-expressing HCC cell lines. ZW251 exhibited potent and target-specific cytotoxicity in a panel of HCC cells cultured either in monolayer or as 3D spheroids. ZW251 showed effective bystander-mediated killing of GPC3 negative cancer cells when in co-culture with GPC3 positive cancer cells. The ZW251 antibody demonstrated a favorable PK profile in Tg32 mice. A single administration of ZW251 resulted in robust tumor growth inhibition of a large panel of CDX and PDX models representing a range of GPC3-expression. Overall, these results support the potential of ZW251 as a novel therapeutic agent against GPC3-bearing cancers. Citation Format: Laurence Madera, Andrea Hernández Rojas, Raffaele Colombo, Alex Wu, Chayne L. Piscitelli, Dunja Urosev, Allysha Bissessur, Chi Wing Cheng, Renee Duan, Catrina Kim, Kevin Yin, Vincent Fung, Kaylee Wu, Winnie Cheung, Diego A. Alonzo, Mark E. Petersen, Stuart D. Barnscher, Jamie R. Rich. ZW251, a novel glypican-3-targeting antibody drug conjugate bearing a topoisomerase 1 inhibitor payload [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2658.

Abstract 2589: Dysregulation of RalGAPA2 in hepatocellular carcinoma

Abstract RalGTPases are Ras-like G-proteins which cycle between the active GTP-bound and the inactive GDP-bound forms. Elevation of expression and activity of RalGTPase has been demonstrated to play an oncogenic role in human cancers. RalA activity could be positively regulated by RalGEF and negatively regulated by RalGAP. The functional RalGAP complex consists of either one of the catalytic subunits, RalGAPA1 or RalGAPA2, together with the regulatory subunit, RalGAPB. In this study, we aimed to investigate the potential role of RalGAPA2 dysregulation and its functional significance in hepatocellular carcinoma (HCC). By RNA-sequencing analysis in human HCC tissues and cell lines, we found that RalGAPA2 was the predominantly expressed RalGAP catalytic subunit in the liver. To examine the RalGAPA2 expression in HCC, we performed qPCR analysis in paired HCC tissues (n=90), and 37.8% of the HCC samples showed a 2-fold downregulation of RalGAPA2. Clinically, downregulation of RalGAPA2 was significantly correlated with a lower cellular differentiation (P=0.034) and a shorter overall survival rate (P=0.045). Interestingly, HCC tumors showing combined upregulation of RalA and downregulation of RalGAPA2 tended to be associated with more aggressive tumor behaviour, including higher occurrence of venous invasion (P=0.001) and more advanced TNM stage (P=0.007). On the other hand, by targeted-DNA sequencing, RalGAPA2 was identified to be recurrently mutated in 7.4% of the patients in a HBV-associated HCC cohort (n=95). Functionally, CRISPR/Cas9-mediated RalGAPA2 knockout HCC cells showed an enhanced migratory ability when compared to the control cells, underlying an upregulation of RalA activity. In HCC, expression of RalA isoform was found to be specifically upregulated and functionally supporting HCC metastasis. Also, inhibition of RalGAP has been demonstrated to promote RalA activity and enhance cell invasion in several cancer types, including oral squamous cell carcinoma, prostate and bladder cancer. Consistently, the inverse correlation between the RalA activity and RalGAPA2 expression was also observed in a panel of HCC cell lines. Furthermore, HCC cells possessing a higher RalA activity were demonstrated to be more prone to RBC8 treatment, a RalGTPase-specific inhibitor. Taken together, our results suggested that RalGAPA2 might play a potential tumor suppressive role in HCC by negatively regulating RalA activity. Citation Format: Lu Tian, Lo Kong Chan, Daniel Wai Hung HO, LuQing Zhao, Irene Oi Lin NG. Dysregulation of RalGAPA2 in hepatocellular carcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2589.

LncRNA TMPO-AS1 Exerts Oncogenic Roles in HCC Through Regulating miR-320a/SERBP1 Axis.

BackgroundPrevious evidence have shown that long non-coding RNA (lncRNA) TMPO antisense RNA 1 (TMPO-AS1) is involved in the aggressiveness of several cancers. Nevertheless, the precise functions of TMOP-AS1 in hepatocellular carcinoma (HCC) are still unresolved.Materials and MethodsThe expressions of TMPO-AS1 and miR-320a were detected in HCC tissues and cells by qRT-RCR. The cell growth, migration and invasion were detected by colony formation, wound healing assay and Transwell assay, respectively. The targeting relation between miR-320a and TMPO-AS1 was predicted by bioinformatics analysis and identified by luciferase reporter gene as well as FISH assay. The expression of SERPINE1 MRNA Binding Protein 1 (SERBP1) was detected by Western blot. The growth of HCC cell was analyzed using transplanted tumor model.ResultsCurrently, we revealed that TMPO-AS1 was overexpressed in clinical HCC samples and a panel of HCC cell lines. Clinically, a higher level of TMPO-AS1 was connected to the advanced stage of HCC and worse prognosis of patients. Depletion of TMPO-AS1 repressed HCC cell viability, migration ability and invasiveness. Nevertheless, upregulation of TMPO-AS1 caused opposite results. Further studies revealed that lncRNA TMPO-AS1 was largely located in the cytoplasm of HCC cell and sponge miR-320a, resulting in increasing the level of SERBP1 in HCC cell. Finally, TMPO-AS1 silencing suppressed tumor growth of HCC cell in vivo.ConclusionCollectively, our results suggested that TMPO-AS1 was a promoting factor for the aggressive behaviors of HCC cell.

ACSL4 is a predictive biomarker of sorafenib sensitivity in hepatocellular carcinoma.

Sorafenib is the first-line treatment of advanced hepatocellular carcinoma (HCC). However, there is a lack of validated biomarkers to predict sorafenib sensitivity. In this study we investigated the role of ACSL4, a positive-activating enzyme of ferroptosis, in sorafenib-induced cell death and HCC patient outcome. We showed that ACSL4 protein expression was negatively associated with IC50 values of sorafenib in a panel of HCC cell lines (R = -0.952, P < 0.001). Knockdown of ACSL4 expression by specific siRNA/sgRNA significantly attenuated sorafenib-induced lipid peroxidation and ferroptosis in Huh7 cells, and also rescued sorafenib-induced inhibition of xenograft tumor growth in vivo. We selected 29 HCC patients with surgery as primary treatment and sorafenib as postoperative adjunct therapy from a hospital-based cohort. A high proportion (66.7%) of HCC patients who had complete or partial responses to sorafenib treatment (according to the revised RECIST guideline) had higher ACSL4 expression in the pretreated HCC tissues, compared with those who had stable or progressed tumor growth (23.5%, P = 0.029). Since ACSL4 expression was independent of sorafenib treatment, it could serve as a useful predictive biomarker. Taken together, this study demonstrates that ACSL4 is essential for sorafenib-induced ferroptosis and useful for predicting sorafenib sensitivity in HCC. This study may have important translational impacts in precise treatment of HCC.

Targeting the Ca2+/Calmodulin-dependent protein kinase II by Tetrandrine in human liver cancer cells

Hepatocellular carcinoma (HCC) is the most prevalent malignancy in liver and a leading cause of cancer-related deaths. Despite the pressing need for treatment options, patients with HCC develop significant resistance and adverse side effects to current approved drugs that becomes a major barrier to effective treatment. A natural product Tetrandrine (TET) is a potential alternative treatment option for HCC, with demonstrated effectiveness and low toxicity. However, the mechanisms by which Tetrandrine inhibits HCC are unclear. In the current study, we identify Ca2+/calmodulin-dependent protein kinase II δ (CaMKIIδ) as a potential TET drug target through structural modeling. Screening of a panel of HCC cell lines reveal differential sensitivities toward TET treatment. Interestingly, IC50 of TET inhibition of HCC cell proliferation is positively correlated with CaMKIIδ expression level in these distinct HCC cells. Furthermore, TET treatment resulted in a marked reduction of CaMKIIδ phosphorylation level, and knockdown of CaMKIIδ reduced the sensitivity of HCC cells to TET. Most importantly, CaMKIIδ protein levels in high-grade human HCC samples were significantly elevated as compared to normal liver tissues. Taken together, our studies demonstrate that the natural compound TET targets CaMKIIδ in HCC cells, and that CaMKIIδ level is a potential biomarker to identify HCC patient populations sensitive to Tetrandrine treatment.

Tanshinol inhibits the growth, migration and invasion of hepatocellular carcinoma cells via regulating the PI3K-AKT signaling pathway.

BackgroundTanshinol is an active constituent of Salvia miltiorrhiza and possess anti-inflammatory, antioxidant, and anti-bacterial activity. Herein, we explored the role of tanshinol on the growth and aggressiveness of hepatocellular carcinoma (HCC) cells in vitro and in vivo.Materials and methodsThe proliferation of a panel of HCC cell lines was measured using MTT assay. The expressions of phosphatidylinositol 3 kinase (PI3K) and protein kinase B (AKT) were detected by immunofluorescence staining and immunohistochemical assay. The levels of Bcl-2 and Bax were determined using immunoblotting assay. The secretions of matrix metalloproteinase-2 (MMP-2) and MMP-9 were detected by ELISA. The migration and invasion abilities of HepG2 cell were determined using wound healing and Transwell invasion assays. The apoptosis of HepG2 cell induced by tanshinol was analyzed by Annexin V/propidium iodide staining. A xenograft model was constructed to investigate the inhibitory effect of tanshinol on HepG2 cell growth in vivo. To further investigate the role of tanshinol on the metastasis of HepG2 cell in vivo, an experimental metastasis assay was performed.ResultsTanshinol inhibited the growth and colony formation of HCC cell in vitro. Tanshinol also induced the apoptosis of HepG2 cell and inhibited the migration and invasion of HepG2 cell. In in vivo experiments, tanshinol suppressed the tumor growth and metastasis of HepG2 cell. Furthermore, the phosphorylation of PI3K and AKT was decreased by tanshinol in vitro and in vivo.ConclusionTanshinol exerts its anti-cancer effects via regulating the PI3K-AKT signaling pathway in HCC.

Applied diagnostics in liver cancer. Efficient combinations of sorafenib with targeted inhibitors blocking AKT/mTOR.

Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related deaths worldwide. There is increasing interest in developing specific markers to serve as predictors of response to sorafenib and to guide targeted therapy. Using a sequencing platform designed to study somatic mutations in a selection of 112 genes (HepatoExome), we aimed to characterize lesions from HCC patients and cell lines, and to use the data to study the biological and mechanistic effects of case-specific targeted therapies used alone or in combination with sorafenib. We characterized 331 HCC cases in silico and 32 paired samples obtained prospectively from primary tumors of HCC patients. Each case was analyzed in a time compatible with the requirements of the clinic (within 15 days). In 53% of the discovery cohort cases, we detected unique mutational signatures, with up to 34% of them carrying mutated genes with the potential to guide therapy. In a panel of HCC cell lines, each characterized by a specific mutational signature, sorafenib elicited heterogeneous mechanistic and biological responses, whereas targeted therapy provoked the robust inhibition of cell proliferation and DNA synthesis along with the blockage of AKT/mTOR signaling. The combination of sorafenib with targeted therapies exhibited synergistic anti-HCC biological activity concomitantly with highly effective inhibition of MAPK and AKT/mTOR signaling. Thus, somatic mutations may lead to identify case-specific mechanisms of disease in HCC lesions arising from multiple etiologies. Moreover, targeted therapies guided by molecular characterization, used alone or in combination with sorafenib, can effectively block important HCC disease mechanisms.

Abstract 2944: TGF-β inhibitor galunisertib combined with antiangiogenic therapies showed antitumor effects in vitro and in vivo in hepatocellular carcinoma (HCC)

Abstract Introduction: TGF-β pathway, associated with hepatocellular carcinoma (HCC) progression, can be targeted by galunisertib, a selective ATP-mimetic TGF-β receptor (TβR)-I inhibitor in clinical trials for HCC patients. We investigated the antitumor effects of galunisertib (Galu) combined with antiangiogenic compounds (sorafenib or DC101, a fully human monoclonal antibody antagonizing VEGFR2, mimicking ramucirumab) in HCC. Methods: In vitro, we assessed proliferation (MTT assay), migration (wound healing), and invasion (boyden chambers), in a panel of HCC cell lines. Transgenic mice developing stage-defined HCC were treated from weeks (W)8 to W16 with either vehicle, sorafenib (30mg/kg), Galu (100mg/kg), sorafenib plus Galu, DC101 (40mg/kg, twice weekly, IP), or DC101 plus galunisertib. Tumor growth was evaluated by ultrasound (liver size) and by the number of macronodules at sacrifice. Angiogenesis assessed by Doppler measuring the mean blood flow in the coeliac trunk (TCm) and CD31 staining. Results: In vitro, we showed an inhibition of TGF-induced proliferation, migration and proliferation by Galu, further potentiated by sorafenib. Sorafenib-tolerant cell line SK-Sora was the most sensitive to Galu. In vivo, at W12 &amp; W16, liver size and tumor macronodules number were significantly lower in all treatment arms compared to placebo. At W16, DC101 showed increased tumor control compared to sorafenib regarding liver weight (3,75g±0,39 vs 6,31 g±0,52, p&amp;lt;0.001) and macronodules number (75,7±12.0 vs 139±13,6, p&amp;lt;0.001). Galu/sorafenib and Galu/DC101 combinations showed increased tumor control at W16 as compared to monotherapies. Interestingly, at W16, Galu/DC101 combination showed greater effect on liver weight (3,09g±0,70 vs 3.75g±0,21, p&amp;lt;0.05, number of macronodules (55.1±14.8 vs 109.4±24.3, p&amp;lt;0.001), and micronodules surface (2.0 mm2±0.43 vs 1.43 mm2±0.33, p&amp;lt;0.05) as compared to Galu/sorafenib combination. Angiogenesis decreased in all treatment arms compared to placebo. At W16, we observed a TCm decrease over 50% in the combination arms compared to 24% with sorafenib, 26% with DC101 and 20% with Galu alone, respectively. These results were confirmed by CD31 staining for assessing number of vessels per field. In addition, Galu/sorafenib combination yielded an increased number of monocytes, a decreased number of neutrophils and Kuppfer cells, along with increased NK cells and decreased NKT cells. Dendritic cells as well as B and T cells population did not show particular variation except for CD4+CD25+ T cells that were strongly decreased in sorafenib-treated mice. Conclusion: The combination of galunisertib with sorafenib or DC101 showed promising antitumor activities that were associated with decreased angiogenesis, DC101 displaying increased efficacy as compared to sorafenib. Citation Format: Annemilaï Tijeras-Raballand, Christian Hobeika, Matthieu Martinet, Lucile Astorgues-Xerri, Elise Paven, Marie-Aude Le Bitoux, Anne Maillard, Clarisse Eveno, Marc Pocard, Philippe Bonnin, Alexandre Harari, Eric Raymond, Sandrine Faivre, Armand de Gramont. TGF-β inhibitor galunisertib combined with antiangiogenic therapies showed antitumor effects in vitro and in vivo in hepatocellular carcinoma (HCC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2944.

Abstract 5190: Oncoprotein SET determines the radiosensitivity of hepatocellular carcinoma cell and antagonizing SET augments the effects of radiotherapy via reactivating PP2A-mediated Akt downregulation

Abstract Background: SET is a novel oncoprotein with growing evidence suggesting its roles in promoting the survival of hepatocellular carcinoma (HCC) and other types of malignant disease. Notably, pre-clinical data suggesting SET overexpression in cancer cell leaded to the development of resistance to various anti-cancer medications, and antagonizing SET reversely enhanced therapeutic efficacy. Radiotherapy (RT) is a commonly used anti-cancer modality, but its role for the treatment of HCC is largely limited for the concern of endogenous radioresistance. In this report, we explored the role of SET regarding the radiosensitivity of HCC cells. Furthermore, we explored whether SET serve as a valid target to enhance RT against HCC. Method: A panel of HCC cell lines, including Hep3B, PLC5, HA22T and HA59T, were used for in vitro experiments, and the PLC5 subcutaneous xenograft mice model was used for in vivo testing. HCC cells and tumors were treated with RT and/or SET antagonist and harvested for subsequent experiments. The viability of cancer cells were assessed by sub-G1, colony and sphere formation assay. Molecular events were determined by western blot and PP2A activity. Result: Through manipulating the expression of SET in cancer cells, we showed the crucial role of SET in mediating the effects of RT in HCC cells. Using colony formation and hepatosphere formation assay, we showed that RT significantly reduced the number and size of both tumor colony and sphere formed by Hep3B and PLC5 cells. In contrast, ectopic expression of SET in Hep3B and PLC5 cells abolished the effects of RT. More importantly, SET-knockdown oppositely potentiated the RT-induced growth inhibition in HCC cells. Based on our findings, we hypothesized that targeting SET may exert potential to enhance RT for the treatment of HCC. In order to validate our hypothesis, we tested the effects of RT in combine with a novel SET antagonist, EMQA, developed and characterized in our previous works. As expected, we found that EMQA significantly potentiated the anti-HCC effects of RT in vitro and in vivo. Moreover, we found that antagonizing SET to restore PP2A-mediated p-Akt downregulation was responsible for the synergism between EMQA and RT. Conclusion Oncoprotein SET plays a critical role in affecting the radiosensitivity of HCC cells. Using SET antagonist plus RT showed promising results in pre-clinical HCC models, and yields further investigation. Citation Format: Man-Hsin Hung, Chao-Yuan Huang, Chih-Ting Shih, Min-Hsien Tsai, Yung-Jen Hsiao, Tzu-I Chao, Feng-Shu Hsieh, Chung-Wai Shiau, Kuen-Feng Chen. Oncoprotein SET determines the radiosensitivity of hepatocellular carcinoma cell and antagonizing SET augments the effects of radiotherapy via reactivating PP2A-mediated Akt downregulation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5190. doi:10.1158/1538-7445.AM2017-5190

MTOR inhibition reduces growth and adhesion of hepatocellular carcinoma cells invitro.

Mechanistic target of rapamycin (mTOR) signaling is typically increased in hepatocellular carcinoma (HCC). A panel of HCC cell lines (HepG2, Hep3B and HuH6) was exposed to various concentrations of the mTOR inhibitors, everolimus and temsirolimus, in order to investigate their effects on cell growth, clonal formation, cell cycle progression, and adhesion and chemotactic migration using MTT and clonal cell growth assays, fluorometric detection of cell cycle phases and a Boyden chamber assay. In addition, integrinαandβ adhesion receptors were analyzed by flow cytometry and blocking studies using function blocking monoclonal antibodies were conducted to explore functional relevance. The results demonstrated that everolimus and temsirolimus significantly suppressed HCC cell growth and clonal formation, at 0.1 or 1nM (depending on the cell line). In addition, the number of cells in G0/G1 phase was increased in response to drug treatment, whereas the number of G2/M phase cells was decreased. Drug treatment also considerably suppressed HCC cell adhesion to immobilized collagen. Integrin profiling revealed strong expression of integrin α1, α2, α6 and β1 subtypes; and integrin α1 was upregulated in response to mTOR inhibition. Suppression of integrin α1 did not affect cell growth; however, it did significantly decrease adhesion and chemotaxis, with the influence on adhesion being greater than that on motility. Due to a positive association between integrin α1 expression and the extent of adhesion, whereby reduced receptor expression was correlated to decreased cell adhesion, it may be hypothesized that the adhesion‑blocking effects of mTOR inhibitors are not associated with mechanical contact inhibition of the α1 receptor but with integrin α1‑dependent suppression of oncogenic signaling, thus preventing tumor cell‑matrix interaction.

Synthesis and biological evaluation of novel pyrazolic chalcone derivatives as novel hepatocellular carcinoma therapeutics

Despite having the second highest mortality associated with cancer, currently Sorafenib is the only FDA-approved chemotherapeutic agent available for liver cancer patients which can only improve survival for few months. In this study, various pyrazolic chalcone analogous compounds were synthesized and evaluated as potential chemotherapeutic agents for the treatment of hepatocellular carcinoma (HCC). Modifying the central pyrazole ring at the C(3)-position with different heteroaryl rings and substituting the C(4)-position of pyrazole with differently substituted chalcone moiety produced fouthy two variant compounds. For all these compounds, cytotoxicity was evaluated using sulforhodamine B assay and real time cell growth tracking, respectively. Based on 50% inhibitory concentration (IC50) values, compounds 39, 42, 49, and 52 were shown to exhibit potent cytotoxic activity against all the cancer cell lines tested, and had better cytotoxic activities than the well-known chemotherapeutic drug 5-FU. Therefore, these compounds were chosen to be further evaluated in a panel of HCC cell lines. Flow cytometric analysis of HCC cells treated with compounds 39, 42, 49, and 52 demonstrated that these compounds caused cell cycle arrest at G2/M phase followed by the apoptotic cell death and impaired cell growth as shown by real-time cell growth surveillance. Consistent with these results, western blotting of HCC cells treated with the compounds resulted in molecular changes for cell cycle proteins, where p21 levels were increased independent of p53 and the levels of the key initiators of mitosis Cyclin B1 and CDK1 were shown to decrease upon treatment. In conclusion, chalcone derivatives 42 and 52 show potent bioactivities by modulating the expression of cell-cycle related proteins and resulting in cell-cycle arrest in the HCC cell lines tested here, indicating that the compounds can be considered as preclinical candidates.

Tissue transglutaminase 2 exerts a tumor-promoting role in hepatitis B virus-related hepatocellular carcinoma.

Hepatitis B virus (HBV) infection is a major risk factor which can lead to development of hepatocellular carcinoma (HCC). Tissue transglutaminase-2 (TG2) has been shown to be critical for cancer progression. However, how TG2 promotes the progression of HBV-related HCC remains unknown. In this study, we aimed to explore the expression and function of TG2 on HBV-related HCC progression. The expression levels of TG2 were examined in a series of HBV-related HCC tissues and a panel of HCC cell lines. The effects of TG2 knockdown on the proliferation and migration of HBV-related cells were determined. TG2 expression was found to be significantly upregulated in HBV-related HCC tissues. TG2 expression was higher in HBV-related HCC cell lines than HBV-unrelated HCC cell lines. Moreover, inhibition of TG2 in HCC cell lines HepG2.2.15 and Hep3B could inhibit cell proliferation, migration, and invasion in vitro. Our results indicated that TG2 could serve as a promising target for treatment of HBV-related HCC patients.

Abstract 321: S49076, a novel kinase inhibitor of MET, AXL and FGFR, demonstrates marked in vitro and in vivo efficacy in hepatocellular carcinoma

Abstract Introduction: Hepatocellular carcinoma (HCC) is the second cause of cancer-related deaths worldwide. While sorafenib may improve overall survival in advanced HCC, new therapies are needed. Both preclinical and clinical data support a role of MET and AXL receptor tyrosine kinases in HCC progression. We thus evaluated S49076, a novel MET/AXL/FGFR inhibitor in HCC cell lines in vitro and in a transgenic mouse model of HCC. Materials and Methods: MET and AXL expressions were assessed in a panel of HCC cell lines by western blot. Downstream signaling pathways were investigated in the presence of HGF, GAS6 and S49076. Cell invasion was evaluated on matrigel assay. Transgenic mice developing stage-defined HCC were treated with S49076 (50mg/kg). Tumor response was evaluated measuring liver volume by echo-doppler and the number of tumor nodules at intermediary (12weeks) and final sacrifice (16 weeks). Results: Both MET and AXL are expressed in the majority of HCC lines screened. Notably, a high level of AXL was observed in the SK-HEP1 cells which were therefore selected for further investigation. MET and AXL pathways were strongly stimulated by their respective ligands, HGF and GAS6. Combination of HGF and GAS6 led to marked activation of ERK. S49076 inhibited MET and AXL pathway activation and HGF- and GAS6- induced invasion at nanomolar concentrations. In vivo anti-tumor efficacy of S49076 was demonstrated in a transgenic MET-expressing mouse model of HCC. Conclusion: S49076 displayed strong MET and AXL pathway inhibition and anti-invasive properties in SK-HEP1 HCC cells. Moreover, S49076 demonstrated antitumor activity in a mouse model of HCC. Together, these results would support development of S49076 as an innovative treatment in HCC patients. Citation Format: Annemilai Tijeras-Raballand, Adrien Pasteur-Rousseau, Matthieu Martinet, Philippe Bonnin, Marc Pocard, Sébastien Banquet, Valérie Cattan, Eric Raymond, Armand de Gramont. S49076, a novel kinase inhibitor of MET, AXL and FGFR, demonstrates marked in vitro and in vivo efficacy in hepatocellular carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 321.

Abstract 2831: Composite cyclin dependent kinase inhibition shows potent activity against hepatocellular carcinoma

Abstract Background: Almost a decade after its approval, sorafenib remains the only approved therapy for advanced hepatocellular carcinoma (HCC). Novel treatment is warranted for advanced HCC. Previous preclinical studies reported that inhibition of various cyclin dependent kinases (CDKs), whether cell cycle dependent or independent, showed activity against HCC. Dinaciclib is a potent inhibitor of CDK1, 2, 5, and 9 and has an acceptable safety profile in humans. We thus examined the efficacy of dinaciclib in HCC using preclinical models. Methods: In a panel of HCC cell lines with high Rb expression (HuH7, PLC5, HepG2, SK-Hep1, SNU387, SNU449, SNU426 and SNU475) and low Rb expression (Hep3B and HLE), dinaciclib was examined for its effect on cell viability. The impacts of dinaciclib on cell cycle distribution, apoptosis induction, and the expressions of phospho- (p-) Rb (the target of CDK1 and 2), p-ATM (the target of CDK5), c-myc, and p-RNA polymerase II (the target of CDK9) were explored in selected cell lines including HuH7 and PLC5. The in vivo efficacy of dinaciclib on HCC was tested in mouse xenografts of HuH7 cells implanted subcutaneously. Knockdown of various CDKs using RNA interference was conducted to explore the mechanisms of dinaciclib. Results: Dinaciclib showed potent anti-proliferative activities in all the tested HCC cell lines. The IC50s to dinaciclib by the MTT assay did not significantly differ between cell lines with high Rb expression (8.5 to 20.1 nM) and cell lines with low Rb expression (9.4 to 15.6 nM). After 48 hours of dinaciclib treatment, HuH7 and PLC5 cells showed G2/M arrest in a dose-dependent manner. Apoptosis assays including sub-G1 fraction analysis, DNA fragmentation detection, and cleaved PARP-1 confirmed the occurrence of apoptosis in HuH7 and PLC5 cells treated with dinaciclib. Dinaciclib at the concentration near the IC50 inhibited the phosphorylation of Rb, RNA polymerase II, and ATM in HuH7 and PLC5 cells; it also inhibited the expressions of multiple anti-apoptotic proteins including Mcl-1, XIAP, and survivin. In xenograft studies with HuH7 cells, mice receiving dinaciclib had a significantly slower tumor growth rate compared with mice receiving vehicles. The TUNEL assay showed that tumors treated with dinaciclib exhibited higher apoptosis activity. Mice tolerated the dinaciclib treatment well without significant body weight change. Knockdown of CDK 1, 2, 5, and 9 using RNA interference showed that CDK1 and CDK9 may contribute the most to the efficacy of dinaciclib. Conclusions: Composite knockdown of CDK 1, 2, 5, and 9 with dinaciclib showed potent activity against HCC. (This study was supported by Ministry of Science and Technology, Taiwan [MOST-103-2314-B-002-181-MY2, MOST-103-2314-B-002-090, MOST-103-2314-B-002-092]). Citation Format: Yi-Hsin Liang, Yu-Yun Shao, Yong-Shi Li, Hang Lin, Han-Yu Wang, Ann-Lii Cheng, Chih-Hung Hsu. Composite cyclin dependent kinase inhibition shows potent activity against hepatocellular carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2831.

C6 ceramide sensitizes the anti-hepatocellular carcinoma (HCC) activity by AZD-8055, a novel mTORC1/2 dual inhibitor

Aberrant activation of mammalian target of rapamycin (mTOR) plays pivotal roles in promoting hepatocellular carcinoma (HCC) tumorigenesis and chemoresistance. Here, we tested the potential anti-HCC activity by a novel mTOR complex 1/2 (mTORC1/2) dual inhibitor AZD-8055 and, more importantly, the potential AZD-8055 sensitization effect by a cell-permeable short-chain ceramide (C6). We showed that AZD-8055 mainly exerted moderate cytotoxic effect against a panel of HCC cell lines (HepG2, Hep3B, and SMMC-7721). Co-treatment of C6 ceramide remarkably augmented AZD-8055-induced HCC cytotoxicity. Meanwhile, C6 ceramide dramatically potentiated AZD-8055-induced HCC cell apoptotic death. Further studies demonstrated that AZD-8055 and C6 ceramide synergistically induced anti-survival and pro-apoptotic activity in primary cultured human HCC cells, but not in the non-cancerous human hepatocytes. Signaling studies showed that AZD-8055 and C6 ceramide synergistically suppressed Akt-mTOR complex 1/2 cascade activation. In vivo, AZD-8055 oral administration suppressed HepG2 hepatoma xenograft growth in nude mice, while moderately improving mice survival. Its anti-tumor activity was dramatically potentiated with co-administration of a liposome-packed C6 ceramide. Together, these results demonstrate that concurrent targeting mTORC1/2 by AZD-8055 exerts anti-tumor ability in preclinical HCC models, and its activity is further sensitized with co-administration of C6 ceramide.

In Vitro and In Vivo Anticancer Activity of Gimatecan against Hepatocellular Carcinoma

Objective:Gimatecan is a new camptothecin (CPT) analogue that inhibits tumor growth by targeting DNA topoisomerase I (TOP I) and introducing strong and persistent DNA cleavage. Anti-tumor activity has been demonstrated with a wide range of solid tumors in previous preclinical and clinical studies. Here, we investigated for the first time the effects of gimatecan on the proliferation of hepatocellular carcinoma (HCC) cells both in vitro and in vivo.Methods:Anticancer efficacy of gimatecan were evaluated in a panel of HCC cell lines and corresponding mouse xenograft models. Inhibition of cell proliferation was measured by CellTiter-Glo cell viability assay. In vivo, gimatecan and control preparations were orally administered every four days, for a total of four times. Tumor volume and body weights of the mice were measured twice weekly.Results:In vitro cytotoxicity evaluation showed that gimatecan inhibited the proliferation of a large panel of HCC cell lines in a dose dependent manner, with IC50 values ranging between 12.1~1085.0 nM. In vivo evaluation in mouse xenograft models showed significant antitumor effects of gimatecan at 0.8mg/kg and 0.4mg/kg as compared to the control group.Conclusion:This study suggested that gimatecan may have the potential to be used as a chemotherapeutic agent for the treatment of HCC.

MicroRNA-101 sensitizes hepatocellular carcinoma cells to doxorubicin-induced apoptosis via targeting Mcl-1.

MicroRNAs (miRNAs/miRs) are important regulators of multiple cellular processes, and their dysregulation is a common event in tumorigenesis, including the development of hepatocellular carcinoma (HCC). Studies have shown that certain miRNAs are associated with resistance to chemotherapy or drug sensitization; however, the underlying mechanisms have largely remained elusive. Multiple drug resistance is a major barrier for the treatment of advanced HCC. In the present study, miR-101 was observed to be downregulated in a panel of HCC cell lines, suggesting that it has a tumor suppressor role. Furthermore, transfection of miR-101 significantly enhanced the cytotoxicity of doxorubicin to HepG2 cells. While overexpression of miR-101 did not influence the accumulation of doxorubicin, it promoted the apoptosis-inducing effect of doxorubicin in HepG2 cells. A bioinformatics analysis predicted that miR-101 directly targeted the 3'-untranslated region of myeloid cell leukemia 1 (Mcl-1), which was verified by a luciferase reporter assay. Finally, transfection of HepG2 cells with Mcl-1 expression plasmid inhibited apoptosis caused by doxorubicin plus miR-101 expression. In conclusion, the present study showed that miR-101 is a negative regulator of Mcl-1 in HCC, and the combination of miR-101 expression with doxorubicin may represent a novel approach for the treatment of HCC.