Retracted: MicroRNA-132 protects H9c2 cells against oxygen and glucose deprivation-evoked injury by targeting FOXO3A

Myocardial ischemia/reperfusion injury (MIRI) is a clinically familiar disease, which possesses a great negative impact on human health. But, the effective treatment is still absent. MicroRNAs (miRNAs) have been testified to play a momentous role in MIRI. The purpose of the study aimed to probe the functions of miR-132 in oxygen and glucose deprivation (OGD)-evoked injury in H9c2 cells. miR-132 expression in H9c2 cells accompanied by OGD disposition was evaluated via real-time quantitative polymerase chain reaction. After miR-132 mimic and inhibitor transfections, the impacts of miR-132 on OGD-affected H9c2 cell viability, apoptosis, cell cycle, and the interrelated factors were appraised by exploiting cell counting kit-8, flow cytometry, and western blot analysis. FOXO3A expression was estimated in above-transfected cells, meanwhile, the correlation between miR-132 and FOXO3A was probed by dual-luciferase report assay. Ultimately, above mentioned cell processes were reassessed in H9c2 cells after preprocessing OGD administration and transfection with si-FOXO3A and si-NC plasmids. We got that OGD disposition obviously enhanced miR-132 expression in H9c2 cells. Overexpressed miR-132 evidently reversed OGD-evoked cell viability repression and apoptosis induction in H9c2 cells. In addition, overexpressed miR-132 mitigated OGD-evoked G0/G1 cell arrest by mediating p21, p27, and cyclin D1 expression. Repression of FOXO3A was observed in miR-132 mimic-transfected cells, which was also predicated as a direct gene of miR-132. We discovered that silenced FOXO3A alleviated OGD-evoked cell injury in H9c2 cells via facilitating cell viability, hindering apoptosis and restraining cell arrest at G0/G1 phase. In conclusion, these investigations corroborated that miR-132 exhibited the protective impacts on H9c2 cells against OGD-evoked injury via targeting FOXO3A.     

LncRNA CYTOR attenuates sepsis-induced myocardial injury via regulating miR-24/XIAP

This work aims to investigate the function and mechanism of long non-coding RNA (lncRNA) cytoskeleton regulator RNA (CYTOR) in myocardial injury induced by sepsis. The sepsis-induced myocardial injury model in mice was established by intraperitoneal injection of LPS (10 mg/kg) in vivo, and cardiomyocyte H9c2 was treated with LPS to mimic sepsis in vitro. CYTOR expression and miR-24 expression were detected by qRT-PCR. After up-regulation or down-regulation of CYTOR and miR-24 expression in the H9c2 cells, and the viability of the cells was detected via MTT assay, and cell apoptosis was detected by TUNEL assay. Western blot was applied to determine the expression level of caspase 3, Bax and X-chromosome-linked inhibitor of apoptosis (XIAP). Interaction between CYTOR and miR-24 was determined by bioinformatics analysis, RT-PCR and dual luciferase reporter assay. Interaction between miR-24 and XIAP was determined through bioinformatics analysis, RT-PCR, western blot and dual luciferase reporter assay. CYTOR was markedly down-regulated. CYTOR interacted with miR-24, and negatively regulated its expression level. Over-expression of CYTOR or transfection of miR-24 inhibitors significantly promoted viability and inhibited apoptosis of H9c2 cells, while the knockdown of CYTOR and transfection of miR-24 mimics had opposite effects. CYTOR suppressed the expression level of apoptosis-related proteins, but miR-24 increased them. miR-24 directly targeted the 3'UTR of XIAP, and suppressed it, and XIAP was modulated indirectly by CYTOR. Down-regulation of CYTOR aggravates sepsis-induced cardiac injury via regulating miR-24 and XIAP.     

Knockdown of LncRNA PVT1 inhibits tumorigenesis in non-small-cell lung cancer by regulating miR-497 expression

Plasmacytoma variant translocation1 (PVT1) was reported to be upregulated in non-small-cell lung cancer (NSCLC) tissues, serve as a promising biomarker for diagnosis and prognosis of NSCLC, and promoted NSCLC cell proliferation. However, the detailed molecular mechanism of PVT1 involved in the pathogenesis and development of NSCLC remains largely unknown. In this study, the expression levels of PVT1 and miR-497 in NSCLC cells were determined by qRT-PCR. Cell viability, invasion and apoptosis were detected by MTT assay, cell invasion assay and flow cytometry analysis, respectively. RNA immunoprecipitation (RIP) and luciferase reporter assay were performed to confirm whether PVT1 directly interacts with miR-497. A xenograft mouse model was established to confirm the effect of PVT1 on tumor growth in vivo and the underlying molecular mechanism. Our findings indicated that PVT1 was significantly upregulated and miR-497 was markedly downregulated in NSCLC cell lines. si-PVT1 effectively decreased the expression of PVT1 and increased the expression of miR-497. PVT1 knockdown remarkably inhibited cell viability, invasion and promoted apoptosis in NSCLC cells. RIP and luciferase reporter assay demonstrated that PVT1 could directly interact with miR-497. Moreover, PVT1 overexpression reversed the inhibitory effect of miR-497 on cell viability, invasion and promotion effect on apoptosis of NSCLC cells. Furthermore, in vivo experiment showed that knockdown of PVT1 inhibited tumor growth in vivo and promoted miR-497 expression. In conclusion, knockdown of PVT1 inhibited cell viability, invasion and induced apoptosis in NSCLC by regulating miR-497 expression, elucidating the molecular mechanism of the oncogenic role of PVT1 in NSCLC and providing an lncRNA-directed target for NSCLC.     

Post-menopausal oestrogen deficiency induces osteoblast apoptosis via regulating HOTAIR/miRNA-138 signalling and suppressing TIMP1 expression

In this study, we aimed to explore the molecular mechanisms underlying the development of osteoporosis in post-menopausal females. Real-time PCR was conducted to measure the expression of potential lncRNAs involved in the osteoporosis of post-menopausal females. In addition, Western blot and IHC assays were used to study the possible correlation among HOTAIR, miR-138 and TIMP1, while a computational analysis was carried out to predict the ‘seed sequence’ responsible for the binding between miR-138 and HOTAIR/TIMP1. Furthermore, luciferase reporter assays were conducted to validate the negative regulatory relationship between miR-138 and TIMP1/HOTAIR. To evaluate the effect of oestrogen on the function of HOATIR and its downstream effectors, luciferase activity was measured in cells cotransfected with different vectors or treated with different doses of oestrogen. The results of the luciferase assay were further validated by real-time PCR, Western blot, MTT assay and flow cytometry. Among the candidate lncRNAs, HOTAIR was the only lncRNA down-regulated in post-menopausal females. HOTAIR bound to miR-138 and negatively regulated its expression. Meanwhile, miR-138 could also bind to TIMP1 mRNA and reduce its expression. Furthermore, a dose-dependent up-regulation of HOTAIR was observed in cells treated with oestrogen, and the elevated HOTAIR increased the level of TIMP1 by targeting miR-138. In addition, oestrogen promoted cell viability and suppressed cell apoptosis, and effects of oestrogen were blocked by the silencing of HOTAIR. Therefore, it can be concluded that oestrogen deficiency could induce the apoptosis of osteoblasts and lead to osteoporosis in post-menopausal females via modulation of the HOTAIR/miR-138/TIMP1 signalling axis.     

miR-142-3p is a tumor suppressor that inhibits estrogen receptor expression in ER-positive breast cancer

Estrogen receptors (ERs) are involved in the development of many types of malignant tumors, in particular, breast cancer. Among others, ERs affect cell growth, proliferation, and differentiation. The microRNA (miRNA) miR-142-3p has been shown to inhibit carcinogenesis by regulating various cellular processes, including cell cycle progression, cell migration, apoptosis, and invasion. It does so via targeting molecules involved in a range of signaling pathways. We surgically collected 20 ER-positive breast cancer samples, each with matched adjacent normal breast tissue, and measured the expression of miR-142-3p via quantitative real-time polymerase chain reaction (qRT-PCR). Bioinformatics methods, luciferase reporter assay, qRT-PCR, and western blot analysis were used to assess whether miR-142-3p could target ESR1, which encodes the estrogen receptor, in ER-positive breast cancer cells and patient samples. We also restored miRNA expression and performed cell viability, cytotoxicity, and colony formation assays. Western blot analysis and qRT-PCR were used to study the expression of apoptosis and stemness markers. We found that miR-142-3p is downregulated in ER-positive breast cancers. Restoration of miR-142-3p expression in ER-positive breast cancer cells reduced cell viability, induced apoptosis via the intrinsic pathway and decreased both colony formation and the expression of stem cell markers. Bioinformatic analysis predicted miR-142-3p could bind to 3′-untranslated region ESR1 messenger RNA (mRNA). Consistently, we demonstrated that miR-142-3p reduced luciferase activity in ER-positive breast cancer cells, and decreased ESR1 expression in both mRNA and protein levels. The results revealed miR-142-3p and ESR1 expression correlated negatively in ER-positive breast cancer samples. The results suggest miR-142-3p acts as a tumor suppressor via multiple mechanisms. Thus, restoration of miR-142-3p expression, for example, via miRNA replacement therapy, may represent an effective strategy for the treatment of ER-positive breast cancer patients.     

miR-144 reverses cisplatin resistance in cervical cancer via targeting LHX2

Mounting evidence showed that microRNAs involve in development and chemoresistance of various human cancers. We explored the roles and mechanisms of miR-144 in resistance to cisplatin (CDDP) of cervical cancer cells. miR-144 and LIM homeobox 2 (LHX2) expression in CDDP-resistant and the parental cells was determined by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analysis, respectively. The functions of miR-144 overexpression on cell viability, the incidence of apoptosis, the activity of caspase-3/7, the cleaved-caspase-3 expression, cell migration, and invasion were determined in Hela cells and Hela/CDDP cells. Overexpression of miR-144 reduced cell viability, induced cell apoptosis, and inhibited cell migration and invasion after CDDP treatment. Besides, a luciferase reporter system demonstrated that miR-144 could directly bind to the 3′ untranslated region (3′-UTR) of LHX2 messenger RNA (mRNA). Gain expression of miR-144 decreased the expression of LHX2 both in mRNA and protein levels. Furthermore, restoration of LHX2 partly abolished the biological functions of miR-144 in resistance of cervical cancer cells. Taken together, miR-144 overcomes resistance to CDDP via promoting cell apoptosis and inhibiting invasion through targeting LHX2 in cervical cancer cells.     

The lncRNA small nucleolar RNA host gene 5 regulates trophoblast cell proliferation,invasion, and migration via modulating miR-26a-5p/N-cadherin axis

Pre-eclampsia (PE) is a pregnancy-specific disease characterized by the occurrence of hypertension and proteinuria after two weeks of gestation. Long noncoding RNAs (lncRNAs) are emerging as key regulators in PE development. This study aims to investigate the role of lncRNA, small nucleolar RNA host gene 5 (SNHG5), in the pathogenesis of PE. The expression of SNHG5 was significantly downregulated in placental tissues from patients with severe PE compared normal controls. Overexpression of SNHG5 promoted trophoblast (HTR-8/SVneo) cell proliferation, invasion, and migration, and flow cytometry results showed that SNHG5 overexpression inhibited apoptosis and caused a decrease of cell population at the G ₀/G ₁ phase and an increase of cell population at the S phase, while knockdown of SNHG5 had the opposite effects. The interaction between SNHG5 and miR-26a-5p was predicted by bioinformatics analysis and confirmed by luciferase reporter assay and RNA immunoprecipitation, and miR-26a-5p was negatively regulated by SNHG5; miR-26a-5p expression was upregulated in PE placental tissues and was inversely correlated with SNHG5 expression. Furthermore, miR-26a-5p was predicted to target the 3′ untranslated region of N-cadherin, which was confirmed by luciferase reporter assay, and miR-26a-5p overexpression suppressed N-cadherin expression in HTR-8/SVneo cells. N-cadherin mRNA expression was downregulated in PE placental tissues and was positively correlated with SNHG5 expression. Both overexpression of miR-26a-5p and knockdown of N-cadherin suppressed HTR-8/SVneo cell invasion and migration, and also attenuated the effects of SNHG5 on the cellular functions of HTR-8/SVneo cells. In conclusion, our study suggested that SNHG5 promotes trophoblast cell proliferation, invasion, and migration at least partly via regulating the miR-26a-5p/N-cadherin axis.     

Downregulation of microRNA-103a reduces microvascular endothelial cell injury in a rat model of cerebral ischemia by targeting AXIN2

Multiple microRNAs (miRNAs) have been found to be linked with cerebral ischemia. Thus, this study was employed to characterize the capabilities of miRNA-103a (miR-103a) on the brain microvascular endothelial cells (BMECs) injury in rat models of middle cerebral artery occlusion (MCAO) by regulating AXIN2. The MCAO rat model was developed by the suture method, where normal saline, miR-103a inhibitors, or its negative control were separately injected into the lateral ventricle to assess the function of miR-103a inhibitors in BMECs apoptosis, microvessel density, as well as angiogenesis. In addition, the oxygen-glucose deprivation model was induced in primarily cultured BMECs to unearth the functions of miR-103a inhibitors on cell viability and apoptosis, lactate dehydrogenase (LDH) release and tube formation ability. Furthermore, the relationship between miR-103a and AXIN2 was verified. The modeled rats of MCAO showed robustly expressed miR-103a, poorly expressed AXIN2, severe neurological deficits, accelerated apoptosis and reduced angiogenesis. miR-103a expression had a negative correlation with AXIN2 messenger RNA expression (r = −0.799; p < .05). In response to the treatment of miR-103a inhibitors, the BMECs apoptosis was suppressed and angiogenesis was restored, corresponding to upregulated Bcl-2, VEGF, and Ang-1, in addition to downregulated caspase-3 and Bax. Meanwhile, AXIN2 was verified to be the miR-103a's target gene. More important, miR-103a inhibitors led to promoted BMEC viability and tube formation and suppressed apoptosis and LDH release rate. This study highlights that miR-103a targets and negatively regulates AXIN2, whereby reducing BMEC injury in cerebral ischemia.     

Dysregulation of microRNA-181b and TIMP3 is functionally involved in the pathogenesis of diabetic nephropathy

This study aimed to study the roleof microRNA (miR)-181b and its target TIMP3 in the development of diabetic nephropathy (DMN) via inhibiting the apoptosis of mesangial cells. Real-time polymerase chain reaction (RT-PCR) was adopted to compare the miR-181b expression between subjects with diabetic nephropathy (DN) and normal control. In addition, luciferase assays were utilized to explore the regulatory relationship between TIMP3 and miR-181b. Real-time PCR and densitometry analysis were conducted to measure the levels of TIMP3 mRNA/protein in DMN or in cells treated by miR-181b inhibitors, miR-181b mimics, and TIMP3 siRNA. And the 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was adopted to study the effect of miR-181b on cell survival and apoptosis. miR-181b expression was much higher in the DN group, and the results of computational analysis identified TIMP3 as a miR-181b target. The luciferase activity of cells transfected with wild-type TIMP3 and mutant2 TIMP3 was significantly reduced, whereas the luciferase activity of cells transfected with mutant1 TIMP3 was evidently higher. Furthermore, a negative regulatory relationship was established between TIMP3 and miR-181b expression with a correlation efficient of −0.5351. The levels of TIMP3 mRNA/protein expression were apparently increased in the DN group. In addition, the treatment of cells with miR-181b mimics and TIMP3 siRNA remarkably lowered the levels of TIMP3 mRNA/protein, whereas the transfection of cells with miR-181b inhibitors notably elevated the expression of TIMP3 mRNA/protein. miR-181b promoted the survival of cells and inhibited their apoptosis. The miR-181b expression was related to the development of DMN and could be used as a prognosis biomarker of DMN in the patients with DM.     

CircINHA resists granulosa cell apoptosis by upregulating CTGF as a ceRNA of miR-10a-5p in pig ovarian follicles

Mammalian ovarian follicular atresia is a complex and fine-regulated biological process with active involvement of connective tissue growth factor (CTGF). The emergence of studies of endogenous non-coding RNAs has raised a new aspect for exploration of the regulatory mechanisms involved in follicular atresia. Here, we aimed to illustrate a circRNA involved in the CTGF regulatory pathway during the apoptosis and follicular atresia of pig granulosa cells (GCs). We first detected a decreased expression pattern of CTGF during follicular atresia using IHC, FISH and qRT-PCR and confirmed the anti-apoptosis effect of CTGF in GCs in vitro by CTGF siRNA knockdown. Then, we used a dual luciferase activity assay to demonstrate CTGF as a direct functional target of miR-10a-5p, which was upregulated in atresic follicles and promoted the apoptosis of GCs in vitro. The negative effect of miR-10a-5p on GC viability was confirmed by cell cycle assays, cell proliferation/apoptosis assays and the WB detection of marker proteins. More importantly, we identified a novel circRNA, termed circINHA, that was downregulated during atresia in ovarian follicles, and we confirmed a direct interaction between miR-10a-5p and circINHA. Finally, we demonstrated that circINHA promoted GCs proliferation and inhibited GCs apoptosis via CTGF as a competing endogenous RNA (ceRNA) that directly bound to miR-10a-5p. Taken together, this study provides evidence for the circINHA/miR-10a-5p/CTGF regulatory pathway in follicular GC apoptosis and provides novel insights into the role of circRNAs in the modulation of ovarian physiological functions.     

Retracted: Deletion of long noncoding RNA EFNA3 aggravates hypoxia-induced injury in PC-12 cells by upregulation of miR-101a

Long noncoding RNAs (lncRNAs) have been reported to be involved in several neurological pathogenesis conditions including cerebral ischemia. In the current study, the functions of lncRNA EFNA3 on hypoxia-injured rat adrenal pheochromocytoma (PC-12) cells and the underlying molecular mechanism were studied. The expression of lncRNA EFNA3 was silenced by short hairpin RNA transfection, after which the cells were subjected with hypoxia. Cell viability, migration, invasion, and apoptosis were, respectively, determined by trypan blue staining, Transwell assay, annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) double-staining, and Western blot analysis. The cross regulation between lncRNA EFNA3 and miR-101a, as well as between miR-101a and Rho associated coiled-coil containing protein kinase 2 (ROCK2) were detected by performing quantitative real-time polymerase chain reaction, RNA pull-down, RNA immunoprecipitation, luciferase activity assay, and Western blot analysis. Studies showed that lncRNA EFNA3 was highly expressed in response to hypoxia. Deletion of lncRNA EFNA3 significantly aggravated hypoxia-induced injury in PC-12 cells, as the impairment of cell viability, migration, and invasion, and the inducement of apoptosis. LncRNA EFNA3 worked as a sponging molecule for miR-101a and miR-101a suppression-protected PC-12 cells against hypoxia-induced injury even when lncRNA EFNA3 was silenced. ROCK2 was a target gene of miR-101a. ROCK2 overexpression exhibited neuroprotective activities. Besides, ROCK2 overexpression activated Wnt/β-catenin pathway whereas it deactivated JAK/STAT pathway upon hypoxia. Our study suggests that deletion of lncRNA EFNA3 aggravates hypoxia-induced injury in PC-12 cells by upregulating miR-101a, which further targets ROCK2.     

miR-218 promoted the apoptosis of human ovarian carcinoma cells via suppression of the WNT/β-catenin signaling pathway

MicroRNA-218 (miR-218) is a short, noncoding RNA, with multiple biological functions. In this study, we aimed to investigate the potential effects of miR-218 on the apoptosis of human ovarian carcinoma cells and the underlying mechanisms by which miR-218 exerted its actions. After over-expressing miR-218 in human ovarian carcinoma (OVCAR3) cells, cell viability was determined by MTT method, cell apoptosis was observed by flow cytometry (FCM), mRNA expression of miR-218, Bcl2, Bax was measured by RT-PCR and protein expression levels of Wnt, tankyrase and β-catenin were quantified by Western blots. Over-expression of miR-218 potently suppressed cell viability and promoted the apoptosis of human ovarian carcinoma cells in a time-dependent manner. In addition, the down-regulation of tankyrase expression level was detected in miR-218-over-expressed cells. Following the block of the Wnt/β-catenin signaling pathway using the inhibitor XAV-939, the effects of miR-218 on the proliferation and apoptosis of human ovarian carcinoma cells were significantly suppressed. Augmenting expression of miR-218 and/or miRNA-218 mimicking therapeutics may provide viable avenue for the treatment of ovarian cancer.     

Long noncoding RNA PTPRG-AS1 acts as a microRNA-194-3p sponge to regulate radiosensitivity and metastasis of nasopharyngeal carcinoma cells via PRC1

Protein regulator of cytokinesis 1 (PRC1) has been reported in correlation with various malignancies. Functionality of PRC1 in nasopharyngeal carcinoma (NPC) was investigated, in perspective of long noncoding RNA (lncRNA) regulatory circuitry. Aberrant expressed messenger RNA and lncRNA were screened out from the Gene Expression Omnibus microarray database. NPC cell line CNE-2 was adopted for in vitro study and transfected with mimic or short hairpin RNA of miR-194-3p and PTPRG-AS1. The radioactive sensitivity, cell viability, migration, invasion, and apoptosis were detected. PTPRG-AS1 and PRC1 were upregulated in NPC, whereas miR-194-3p was downregulated. PTPRG-AS1 was found to specifically bind to miR-194-3p as a competing endogenous RNA and miR-194-3p targets and negatively regulates PRC1. Overexpressed miR-194-3p or silenced PTPRG-AS1 resulted in enhanced sensitivity to radiotherapy and cell apoptosis along with suppressed cell migration, invasion and proliferation in NPC. Furthermore, impaired tumor formation was also caused by miR-194-3p overexpression or PTPRG-AS1 suppression through xenograft tumor in nude mice. In our study, PTPRG-AS1/miR-194-3p/PRC1 regulatory circuitry was revealed in NPC, the mechanism of which can be of clinical significance for treatment of NPC.     

microRNA-485-5p inhibits the progression of hepatocellular carcinoma through blocking the WBP2/Wnt signaling pathway

microRNA-485-5p (miR-485-5p) has been shown to act as a tumor-suppressor gene in some cancers, such as ovarian epithelial tumors and oral tongue squamous cell carcinoma. However, with regard to the anti-tumor role of miR-485-5p in hepatocellular carcinoma (HCC), evidence is unexpectedly limited. In the present study, we investigated the expression and the role of miR-485-5p in the progression of HCC. Microarray analysis revealed that miR-485-5p was downregulated and WBP2 was upregulated in HCC, which was consistent with RT-qPCR and immunohistochemistry assays in the HCC tissues we collected. A negative correlation between the expression of miR-485-5p and WBP2 was also found in HCC tissues. It was predicted and confirmed that miR-485-5p could bind to WW domain binding protein 2 (WBP2) through in silico analysis of genetic sequences and an in vitro dual-luciferase reporter gene assay. Next, gain- or loss-of-function studies were applied in the HCC cell line (Huh7) to examine the effects of miR-485-5p and WBP2 on HCC cell behavior. The effects of miR-485-5p and WBP2 on the Wnt/β-catenin signaling pathway were determined by TOP/FOP flash luciferase assays. miR-485-5p was shown to downregulate WBP2 and block the Wnt/β-catenin signaling pathway. As expected, elevated miR-485-5p levels and inhibition of WBP2 protein expression exerted inhibitory effects on HCC cell proliferation, migration and invasion and, induced apoptosis. In vivo experiments were finally conducted, which confirmed that upregulation of miR-485-5p or depletion of WBP2 attenuated tumor growth. Collectively, our results suggest miR-485-5p can downregulate WBP2 to inhibit the development of HCC by the blockade of the Wnt/β-catenin signaling, providing a novel molecular target for HCC treatment.     

miR-26b enhances the sensitivity of hepatocellular carcinoma to Doxorubicin via USP9X-dependent degradation of p53 and regulation of autophagy

Multi-drug resistance is a major challenge to hepatocellular carcinoma (HCC) treatment, and the over-expression or deletion of microRNA (miRNA) expression is closely related to the drug-resistant properties of various cell lines. However, the underlying molecular mechanisms remain unclear. CCK-8, EdU, flow cytometry, and transmission electron microscopy were performed to determine cell viability, proliferation, apoptosis, autophagic flow, and nanoparticle characterization, respectively. In this study, the results showed that the expression of miR-26b was downregulated following doxorubicin treatment in human HCC tissues. An miR-26b mimic enhanced HCC cell doxorubicin sensitivity, except in the absence of p53 in Hep3B cells. Delivery of the proteasome inhibitor, MG132, reversed the inhibitory effect of miR-26b on the level of p53 following doxorubicin treatment. Tenovin-1 (an MDM2 inhibitor) protected p53 from ubiquitination-mediated degradation only in HepG2 cells with wild type p53. Tenovin-1 pretreatment enhanced HCC cell resistance to doxorubicin when transfected with an miR-26b mimic. Moreover, the miR-26b mimic inhibited doxorubicin-induced autophagy and the autophagy inducer, rapamycin, eliminated the differences in the drug sensitivity effect of miR-26b. In vivo, treatment with sp94dr/miR-26b mimic nanoparticles plus doxorubicin inhibited tumor growth. Our current data indicate that miR-26b enhances HCC cell sensitivity to doxorubicin through diminishing USP9X-mediated p53 de-ubiquitination caused by DNA damaging drugs and autophagy regulation. This miRNA-mediated pathway that modulates HCC will help develop novel therapeutic strategies.