Hsa-miR-423-5p selectively loaded in hypoxic exosomes reduces the sensitivity of normoxic hepatocellular carcinoma to sorafenib via autophagy.

Hypoxia and retinoic acid-inducible NDRG1 expression is responsible for doxorubicin and retinoic acid resistance in hepatocellular carcinoma cells

S-palmitoylation of PCSK9 induces sorafenib resistance in liver cancer by activating the PI3K/AKT pathway.

One sentence introduction: This study indicated the potential of combinational therapy of neoantigen vaccine and iNKT activator α-GalCer in Hepatocellular carcinoma. Hepatocellular carcinoma (HCC) is a leading cause of death around the world. Current immune checkpoint blockade therapies only show effectiveness in some cancer patients, so there is an urgent need for more effective immunotherapy strategies. One alternative is the use of neoantigen-based cancer vaccines, which target tumor-specific antigens (neoantigens) on cancer cells and induce strong T-cell responses. Advances in technology now allow for precise identification of tumor neoantigens using bioinformatic analysis or mass spectrometry. While cancer vaccines have demonstrated strong anti-tumor immune responses and therapeutic effectiveness in some cancer types, their success in HCC remains limited. A contributing factor is the suppressive tumor microenvironment (TME) found in advanced HCC. Some studies suggest that combining neoantigen vaccines with anti-PD1/PD-L1 therapies can significantly enhance HCC treatment outcomes. Overcoming the suppressive immune microenvironment is crucial in cancer treatment, and reactivating intratumoral immunity is essential. In our study, we developed an HCC cancer vaccine using transcriptome sequencing and bioinformatics analysis. Our ELISpot assay results showed that this vaccine induced strong tumor-specific immune responses and significantly inhibited tumor growth in early-stage orthotopic HCC mouse models when administered five days after tumor inoculation. However, the effectiveness decreased in advanced tumors when administered ten days after tumor inoculation. We also discovered a significant relationship between the therapeutic effectiveness of the neoantigen vaccine and the activation of intratumoral NKT cells in HCC. Our study suggested that the type-I NKT cell activator, α-Galactosylceramide (α-GalCer), significantly improved the therapeutic outcomes of the cancer neoantigen vaccine in advanced orthotopic HCC mouse models. In some cases, tumors were almost completely eliminated. This indicates the potential of combining iNKT activators with neoantigen vaccines for HCC treatment. To further understand the role of NKT cells in HCC's TME, we plan to investigate intratumoral NKT cell subtypes following neoantigen vaccine therapy. Additionally, we will develop a new delivery system to deliver type I NKT cell activators and type II NKT inhibitors to tumor sites, aiming to reactivate the suppressive TME in HCC after neoantigen vaccine therapy. Citation Format: Renhao Li, Jing-Chu Hu, Li Rong, Yangfan Wu, Yige He, Jiandong Huang. NKT activation enhanced the therapeutic efficacy of neoantigen vaccine in hepatocellular carcinoma [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 6755.

Although arsenic trioxide (ATO) is used in the treatment of advanced hepatocellular carcinoma (HCC) in clinical trials, it is not satisfactory in terms of improving HCC patients' overall survival. Intratumoral hypoxia and overexpression of hypoxia-inducible factor-1α (HIF-1α) may result in ATO resistance and tumor progression. We investigated the mechanisms involving HIF-1α expression and acquired ATO chemoresistance in HCC cells and mice. The therapeutic effects of ATO in normoxic and hypoxic HCC cells were assessed using cell viability and apoptosis assays in vitro and a xenograft model in vivo. mRNA and protein expression of HIF-1α, P-glycoprotein, and VEGF were measured by qRT-PCR and western blotting. HIF-1α inhibition was performed to investigate the mechanism of ATO resistance. VEGF secretion was tested using ELISA and tube formation assays. Compared to normoxic cells, hypoxic HCC cells were more resistant to ATO, with higher IC50 values and less apoptosis, and upregulated HIF-1α protein expression, accompanied with the enhancement of P-glycoprotein and VEGF synthesis after ATO treatment. VEGF secretion was elevated in the supernatant of ATO-treated HCC cells, and this change can potentiate angiogenesis in vitro. HIF-1α inhibition attenuated ATO resistance and angiogenesis and promoted the anticancer effects of ATO both in vitro and in vivo by downregulating therapy-induced P-glycoprotein and VEGF overexpression. Hypoxic HCC cells acquire ATO resistance by upregulating HIF-1α levels; thus, combining ATO with a HIF-1α-targeting agent may lead to enhanced antitumor effects in HCC.

Objective: To explore the effects of hypoxic exosomes secreted from hepatocellular carcinoma Huh7 cells on the proliferation, migration and invasion under co-cultured normoxic condition. Methods: Hypoxic exosomes secreted from Huh7 cells under hypoxic conditions were extracted by differential ultracentrifugation. Transmission electron microscopy, nanoparticles tracking analysis and western blot were used for the identification of hypoxic exosomes. Hypoxic exosomes were co-cultured with Huh7 cells under normoxic conditions. CCK8, cell scratch and transwell assay were used to detect the changes of cell proliferation, migration and invasion. Statistical analysis was performed by one-way ANOVA and t-test. Results: Hypoxic exosomes secreted from Huh7 cells ranged in size from 30 to 150 nm in diameter, and expressed exosome surface markers CD9, CD63 and TSG101. Hypoxic exosomes significantly enhanced the proliferation of normoxic Huh7 cells (A value of hypoxic exosomes and control group at 48 and 72 h were 2.131 ± 0.092 and 1.760 ± 0.104,t= 3.740,P<0.01, 3.121 ± 0.157 and 2.298 ± 0.085,t= 8.289,P< 0.01). The migration distance between hypoxic exosome and control group at 48 and 72 h were (0.37 ± 0.06 cm)and(0.19 ± 0.05 cm),t= 4.813,P< 0.05, (1.15 ± 0.07 cm) and(0.62 ± 0.08 cm),t= 8.874,P< 0.05, and invasion ability [hypoxic exosomes and control group were (123 ± 18), (44 ± 12),t= 6.203,P< 0.01]. Conclusion: Hypoxic exosomes secreted from hepatocellular carcinoma Huh7 cells can promote cell proliferation, migration and invasion in hypoxic environment, suggesting that intercellular information transmission mediated by hypoxic exosomes may be one of the key mechanisms for the amplification of malignancy of hepatocellular carcinoma cells in hypoxic microenvironment.

BackgroundRadiotherapy resistance is a major obstacle in the treatment of oesophageal squamous cell carcinoma (OSCC). Hypoxia is a critical cause of radioresistance. However, the communication between hypoxic cells and aerobic cells via exosomes during the transfer of radiation resistance remains unclear.MethodsExo-miR-340-5p levels were analysed by RNA-seq and qRT-PCR. We co-cultured OSCC cells with isolated normoxic and hypoxic exosomes to study their impact on radiosensitivity. We used a specific exo-miR-340-5p mimic and knock-down retrovirus to explore the role of this miRNA in the transfer of radioresistance from hypoxic to normoxic cells. Dual-luciferase reporter and RIP assays were used to verify KLF10 as a putative target of miR-340-5p. Several in vitro assays were conducted and xenograft models were established to investigate the effect of exo-miR-340-5p on OSCC radiosensitivity. The plasma exo-miR-340-5p levels in OSCC patients were analysed to study the clinical value of this parameter.ResultsHypoxic exosomes alleviated radiation-induced apoptosis and accelerated DNA damage repair. miR-340-5p was highly expressed in hypoxic exosomes and was transferred into normoxic cells, where it induced radioresistance. Overexpression of miR-340-5p in normoxic OSCC cells mimicked the radioresistance of cells co-cultured with hypoxic exosomes. Knockdown of miR-340-5p in hypoxic exosomes reversed the radioresistance effect, indicating that exo-miR-340-5p is critical for hypoxic EV-transferred radioresistance. KLF10 was identified as the direct target of miR-340-5p. Moreover, metformin was found to increase the expression of KLF10 and enhance the radiosensitivity of OSCC. Higher levels of miR-340-5p in the plasma exosomes from OSCC patients are related to a poorer radiotherapy response and prognosis.ConclusionsHypoxic tumour cell-derived exosomal miR-340-5p confers radioresistance in OSCC by targeting KLF10/UVRAG, suggesting that miR-340-5p could be a potential biomarker and therapeutic target for the enhancement of radiosensitivity in OSCC. Metformin can increase KLF10 expression, which ameliorates the radioresistance induced by exo-miR-340-5p transfer. Therefore, metformin could be further investigated as a therapeutic option for the treatment of OSCC.

Hypoxia is often found in solid tumors and is associated with tumor progression and poor clinical outcomes. We elucidated the mechanism by which netrin-1 released under hypoxic stress can induce epithelial-mesenchymal transition (EMT) to promote invasion in hepatocellular carcinoma (HCC) cells. The expression of netrin-1 and the dependent receptors UNC5H and deleted in colorectal cancer (DCC) in HCC was examined by immunohistochemistry or western blot. The HepG2 cells were cultured in 21% O2 (normoxia) or 1% O2 (hypoxia) for 24 h. The release of netrin-1 from hypoxic cells was detected by ELISA. Expression of E-cadherin and vimentin were examined by western blot. Inverted microscopy or confocal microscopy was used to show the cell morphology or cytoskeletal rearrangements. Cell invasion induced by hypoxia was analyzed by Transwell chamber. Cytokine IL-8 and IL-10 mRNA levels were assessed by real-time PCR. The expression of netrin-1 was increased in HCC tissue and cell lines. The dependent receptors UNC5H and DCC were decreased in most HCC cell lines. Hypoxia induced netrin-1 release in a time-dependent manner. EMT induction was found to occur in hypoxic HCC cells in a process that was dependent on the extracellular release of netrin-1. Moreover, overexpression of netrin-1 resulted in EMT induction in normoxic tumor cells. Cytoskeletal rearrangements were found to occur and cell invasion was increased in cells with netrin-1 overexpression. Lastly, mRNA of IL-8 and IL-10 were also increased after recombinant human netrin-1 treatment. These results suggest that in hypoxic HCC cells, netrin-1 activates downstream signaling pathways to induce EMT activation with subsequent production of multiple inflammatory mediators which in turn promotes cancer invasion.

Background: Hypoxia plays an important role in the lung metastasis of hepatocellular carcinoma (HCC). However, the process by which hypoxia promotes the formation of a pre-metastatic niche (PMN) and its underlying mechanism remain unclear. Methods: Exosomes derived from normoxic and hypoxic HCC cells were collected to induce fibroblast activation in vitro and PMN formation in vivo. The micro RNA (miR) profiles of the exosomes were sequenced to identify differentially expressed miRNAs. Gain- and loss-of-function analyses were performed to investigate miR-4508 function. Dual-luciferase, western blotting, and real-time reverse transcription-PCR analyses were used to identify the direct targets of miR-4508 and its downstream signaling pathways. To demonstrate the roles of hypoxic tumor-derived exosomes (H-TDEs) and miR-4508 in the lung metastasis of liver cancer, H22 tumor cells were injected through the tail vein of mice. Blood plasma-derived exosomes from patients with HCC who underwent transarterial chemoembolization (TACE) were applied to determine clinical correlations. Results: We demonstrated that H-TDEs activated lung fibroblasts and facilitated PMN formation, thereby promoting lung metastasis in mice. Screening for upregulated exosomal miRNAs revealed that miR-4508 and its target, regulatory factor X1 (RFX1), were involved in H-TDE-induced lung PMN formation. Moreover, miR-4508 was significantly upregulated in plasma exosomes derived from patients with HCC after TACE. We confirmed that the p38 MAPK-NF-κB signaling pathway is involved in RFX1 knockdown-induced fibroblast activation and PMN formation. In addition, IL17A, a downstream target of RFX1, was identified as a link between RFX1 knockdown and p38 MAPK activation in fibroblasts. Conclusion: Hypoxia enhances the release of TDEs enriched with miR-4508, thereby promoting lung PMN formation by targeting the RFX1-IL17A-p38 MAPK-NF-κB pathway. These findings highlight a novel mechanism underlying hypoxia-induced pulmonary metastasis of HCC.

HIF-1 plays a pivotal role in cancer development via cellular growth,proliferation, survival, metabolism and angiogenesis. High expression of HIF-1α, a regulatory component of HIF-1, in cancer cells is due to increased synthesis of HIF-1α via the increased translation of HIF-1α mRNA under the influence of activated mTORC1 signaling as well as decreased HIF-1α degradation that is either on oxygen-dependent or independent mechanism. In mouse hepatocarcinogenesis, our previous data demonstrated that HIF-1α is overexpressed depending on the PI3K-Akt pathway from earliest stage and that HIF-1α knockdown by using siRNA resulted in marked growth retardation and cell death in HCC cells. We here demonstrated that Akt, 4E binding protein 1 (4EBP1) and p70 ribosomal protein S6 kinase (S6K) were hyperphosphorylated in mouse hepatic tumors and HCC cells, indicating that the PI3K-Akt-mTORC1 pathway was activated. However, although rapamycin, an inhibitor of mTORC1, effectively suppressed phosphorylation of 4EBP1 and S6K in HCC cells, HCC cells were resistant to rapamycin where HIF-1α continued to be expressed during rapamycin treatment. This HIF-1α expression was due to de novo synthesis of HIF-1α during rapamycin treatment as well as HIF-1α stabilization due to binding of HIF-1α to HSP90 that was constitutively over-expressed in the HCC cells. On the other hand, rapamycin induced extensive hemorrhagic necrosis in HCC tissues in vivo but not in normal liver or adenomas (benign lesions). Phosphorylated ribosome protein subunit 6 (rps6), the downstream phosphorylation target of mTORC1-S6K pathway, was specifically detected in the endothelial cells within HCCs but not those in normal liver or adenomas. Furthermore, rapamycin decreased proliferation of endothelial cells in vitro, reducing HIF-1α expression together with the decreased 4EBP and S6K phosphorylation, indicating that the endothelial cells within HCCs were especially sensitive to rapamycin. Dual treatment with inhibitors for mTOR and HSP90, therefore, could target both HCC cells and endothelial cells within HCCs, which might be an effective therapy for HCCs. Citation Format: Hiroki Tanaka, Masahiro Yamamoto, Masaaki Miyakoshi, Katsuhiro Ogawa. Rapamycin-resistant HIF-1α expression in hepatocellular carcinoma (HCC) cells and high sensitivity of endothelial cells within HCC tissues to rapamycin. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4016. doi:10.1158/1538-7445.AM2013-4016

Hypoxic microenvironment is a hallmark feature of hepatocellular carcinoma (HCC) and contributes to cancer progression. RHPN1-AS1, a long noncoding RNA (lncRNA), plays an important role in multiple cancers. However, its expression and oncogenic function under hypoxic conditions have not yet been determined. In this study, we investigated the expression changes of RHPN1-AS1 in HCC cells upon hypoxia. The effects of RHPN1-AS1 knockdown and overexpression on hypoxic HCC cells were explored. The protein partner involved in RHPN1-AS1 action in hypoxic HCC cells was characterized. We found that exposure to hypoxia led to an increase in the RHPN1-AS1 level in HCC cells, which was blocked by depletion of HIF-1α. Chromatin immunoprecipitation assay revealed the enrichment of HIF-1α at the promoter of RHPN1-AS1 in hypoxic HCC cells. Knockdown of RHPN1-AS1 suppressed HCC cell proliferation, colony formation, and invasion under hypoxia, whereas overexpression of RHPN1-AS1 promoted the proliferation and invasion of hypoxic HCC cells. Mechanistically, RHPN1-AS1 interacted with and stabilized RPS15A protein in hypoxic HCC cells. Elevated expression of RPS15A protein enhanced the proliferation and invasion of hypoxic HCC cells through activation of β-catenin signaling. Silencing of RPS15A attenuated RHPN1-AS1-induced aggressiveness and β-catenin activation in hypoxic HCC cells. In vivo tumorigenic studies confirmed that RPS15A depletion significantly reduced the growth of RHPN1-AS1-overexpressing HCC xenograft tumors. RHPN1-AS1 serves as a hypoxia-responsive lncRNA and interacts with the RPS15A protein partner to activate the β-catenin pathway, consequently enhancing HCC progression under hypoxia.

Background: The Tumor Growth Factor-β (TGF-β) pathway is a potent tumor suppressor pathway. Its inactivation has been implicated in hepatocarcinogenesis. However, in patients with advanced stage Hepatocellular Carcinoma (HCC), TGF-β1 serum concentrations are elevated and correlated to tumor size, recurrence and shortened survival. The mechanisms mediating TGF-β1 ligand overexpression in HCC are unknown. Material and Methods: Immunohistochemical analysis of human HCC samples was performed using Tissue Micro Array. Established human HCC cell lines were used for in vitro studies. Gene expression was assessed by qRT-PCR, ELISA and immunoblot analysis. shRNA was used for gene silencing. Transcription factor DNA binding was evaluated by chromatin immunoprecipitation. For promoter analysis, transcription factor binding site containing DNA fragments were cloned into the enhancer or promoter position of luciferase expression vectors and subsequent transfected. Results: In up to 68% of advanced stage HCC tumors Stem Cell Factor (SCF) is overexpressed, and SMAD2 and STAT3 are constitutively activated. SCF expression in human HCC tumors is intratumorally and intracellularly correlated to expression of pSer465/467SMAD2 and pTyr705STAT3. In HCC cell lines, SCF stimulation induces TGF-β1 transcription, expression and secretion, all of which are abrogated by genetic silencing of STAT3. TGF-β1 stimulation of human HCC cells induces TGF-β1 transcription, and genetic silencing of SCF prevents TGF-β1 autoregulation. We identified two STAT3 recognition sites within the TGF-β1 gene. In human HCC cells, TGF-β1 stimulation results in STAT3 binding to one of the identified recognition sites. TGF-β1 activates luciferase expression vectors under control of the corresponding STAT3 binding site but not in its absence. TGF-β1-induced STAT3 binding and expression vector activation is abrogated in HCC cells with genetically silenced SCF. TGF-β1 induces SCF expression but SMAD2 knockdown inhibits TGF-β1-induced SCF transcription and expression. We identified 7 putative SMAD2-binding elements (SBE) within the SCF promoter. TGF-β1 stimulation results in SMAD2 binding to the SCF promoter and activation of luciferase expression vectors regulated by the SCF promoter; conversely, genetic silencing of SMAD2 abrogates TGF-β1-induced SCF promoter activation. Importantly, knockdown of SCF restored the antiproliferative functions of TGF-β, and prevented TGF-β-induced tumor cell migration and invasion. Conclusion: In advanced stage HCC, SCF drives TGF-β1 autoregulation through STAT3-mediated regulation of the TGF-β1 promoter. Thereby, SCF and TGF-β1 form a positive feedback loop that functionally switches the TGF-β pathway from a tumor suppressor to a tumor promoter in advanced stage HCC. Citation Format: Pingyu Zhang, Andres Rojas, Ying Wang, Nina M. Munoz, Lianchun Xiao, Jing Wang, Gregory J. Gores, Mien-Chie Hung, Boris R. A. Blechacz. A positive feedback loop between TGF-β and SCF mediates TGF-β1 ligand overexpression in advanced hepatocellular carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3911. doi:10.1158/1538-7445.AM2015-3911

Background: Hypoxia significantly impacts cancer progressions, in various types of solid tumors including ovarian cancer. Exosomes (30-150nm) secreted from cells in the hypoxic tumor microenvironment play a critical role in cancer progression through transferring functional proteins, mRNAs, and miRNAs as mediators of intercellular communication. However, the underlying mechanisms how cancer exosomes induced by hypoxia regulate cancer progressions remain elusive. This study aims to assess the effect of exosomes secreted from hypoxic cancer cells on the metastatic ability of ovarian cancer cells. Methods: Two ovarian cancer cell lines, Kuramochi and SKOV-3, were used. Exosomes from cancer cells cultured under normoxic or hypoxic conditions (normoxic or hypoxic exosomes) were isolated using Exoquick-TC kit and identified by nanoparticle tracking analysis, transmission electron microscopy, and western blotting. BCA assay was done to evaluate the concentration of exosomes. Normoxic or hypoxic exosomes were treated on ovarian cancer cells. Cell migration and invasion abilities were examined by wound healing assay and MatriGel invasion assay respectively. Furthermore, miRNA sequencing was performed to explore the miRNA profiling of hypoxic and normoxic exosomes. Results: The size of exosomes was ranging from 52nm to 121nm (mean diameter = 85nm). The quantity of hypoxic exosomes was significantly more than that of normoxic exosomes. Hypoxic exosomes increased the migration and invasion ability of kuramochi and SKOV-3 cells. In addition, hypoxic exosomes treatment on ovarian cancer cells up-regulated the expression of MMP-2 and Snail-1 at the protein level. MiRNA sequencing showed that miR-376c-3p was significantly upregulated in hypoxic exosomes in both ovarian cancer cell lines. Moreover, miR376c-3p enhanced migration and invasion ability of ovarian cancer cells, validated by miR376c-3p inhibitor and mimics. Conclusions: Taken together, our study suggests that miR376c-3p transferred by hypoxic exosomes could promote the metastatic potential of ovarian cancer cells by inducing MMP-2 and Snail-1. Citation Format: HyunA Jo, Wenyu Wang. Hypoxia-induced exosomal miR-376c-3p promotes metastatic potential of ovarian cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2384.

The immunobiology of hepatocellular carcinoma in humans and mice: Basic concepts and therapeutic implications

Aberrant hypermethylation of promoter regions in cytosine-guanine dinucleotides (CpG) islands has been shown to be associated with transcriptional silencing of tumor-suppressor genes in many cancers. This study evaluated the methylation profile and the tumor-suppressive function of the small heterodimer partner (SHP, NR0B2) in the development of human hepatocellular carcinoma (HCC). Human HCC pathologic specimens and cell lines were used as model systems in this study. The expression of SHP is diminished in HCC pathologic specimens and cell lines by epigenetic silencing owing to SHP promoter hypermethylation. In vitro methylation decreased SHP promoter transactivation and nuclear receptor LRH-1 binding, an event that was reversed by demethylation. Overexpression of SHP inhibited HCC foci formation, arrested HCC tumor growth in xenografted nude mice, and increased the sensitivity of HCC cells to apoptotic stimuli. Further analysis of a total of 19 normal liver and 57 HCC specimens showed that down-regulation of SHP gene expression may be a common denominator of HCC. We propose that SHP functions as a novel tumor suppressor in the development of HCC. These findings provide new insight into the molecular mechanisms leading to this common cancer and may have both diagnostic and therapeutic applications.

Hepatocellular carcinoma (HCC) is a cancer with high morbidity and mortality. There are limited treatment options, particularly for chemotherapy-resistant HCC patients. Circular RNA hsa_circ_0088036 was associated with the development of bladder cancer and non-small cell lung cancer. However, whether it might be a potential therapeutic target for HCC remains elusive. Hsa_circ_0088036 expression was detected in HCC tumor tissues and cell lines using real-time PCR. The influences of hsa_circ_0088036 on proliferation and invasion as well as chemotherapy sensitivity in HCC cells were investigated by gain- and loss-of-function analyses. Associations among hsa_circ_0088036, miR-140-3p, and KIF2A were validated by real-time PCR, miRNA pull-down assay, dual-luciferase reporter assay, and western blot. Furthermore, a rescue experiment using KIF2A overexpression was performed to evaluate the regulatory mechanism of hsa_circ_0088036 in HCC cells. Additionally, the effect and mechanism of hsa_circ_0088036 were confirmed in a xenograft mouse model. Hsa_circ_0088036 was highly expressed in HCC tissues and cells, with even higher expression in oxaliplatin-resistant cells. This expression was positively correlated with tumor size and TNM stage of the patients. Overexpression of hsa_circ_0088036 promoted the proliferation and invasion of HCC cells, while silencing mediated the opposite effects. Meanwhile, knockdown of hsa_circ_0088036 enhanced chemotherapy sensitivity, including oxaliplatin, doxorubicin, and sorafenib, in HCC cells. Furthermore, hsa_circ_0088036 silencing inhibited tumor growth and increased oxaliplatin sensitivity in vivo. Mechanically, hsa_circ_0088036 functioned via the miR-140-3p/KIF2A axis with the activation of PI3K/Akt and Notch signaling pathways. Hsa_circ_0088036 promoted HCC tumorigenesis and chemotherapy resistance by activating the PI3K/Akt and Notch pathways through regulating miR-140-3p/KIF2A signaling. Thus, hsa_circ_0088036 may be a potential therapeutic target in chemotherapy-resistant HCC.