Combination of metformin and sorafenib suppresses proliferation and induces autophagy of hepatocellular carcinoma via targeting the mTOR pathway

Fasting in combination with the cocktail Sorafenib:Metformin blunts cellular plasticity and promotes liver cancer cell death via poly-metabolic exhaustion

PURPOSE

Dual-Interventions targeting glucose and oxidative metabolism are receiving increasing attention in cancer therapy. Sorafenib (S) and Metformin (M), two gold-standards in liver cancer, are known for their mitochondrial inhibitory capacity. Fasting, a glucose-limiting strategy, is also emerging as chemotherapy adjuvant. Herein, we explore the anti-carcinogenic response of nutrient restriction in combination with sorafenib:metformin (NR-S:M).

RESULTS

Our data demonstrates that, independently of liver cancer aggressiveness, fasting synergistically boosts the anti-proliferative effects of S:M co-treatment. Metabolic and Cellular plasticity was determined by the examination of mitochondrial and glycolytic activity, cell cycle modulation, activation of cellular apoptosis, and regulation of key signaling and metabolic enzymes. Under NR-S:M conditions, early apoptotic events and the pro-apoptotic Bcl-xS/Bcl-xL ratio were found increased. NR-S:M induced the highest retention in cellular SubG1 phase, consistent with the presence of DNA fragments from cellular apoptosis. Mitochondrial functionality, Mitochondrial ATP-linked respiration, Maximal respiration and Spare respiratory capacity, were all found blunted under NR-S:M conditions. Basal Glycolysis, Glycolytic reserve, and glycolytic capacity, together with the expression of glycogenic (PKM), gluconeogenic (PCK1 and G6PC3), and glycogenolytic enzymes (PYGL, PGM1, and G6PC3), were also negatively impacted by NR-S:M. Lastly, a TMT-proteomic approach corroborated the synchronization of liver cancer metabolic reprogramming with the activation of molecular pathways to drive a quiescent-like status of energetic-collapse and cellular death.

CONCLUSION

Altogether, we show that the energy-based polytherapy NR-S:M blunts cellular, metabolic and molecular plasticity of liver cancer. Notwithstanding the in vitro design of this study, it holds a promising therapeutic tool worthy of exploration for this tumor pathology.

Effects of metformin on cancers in experimental and clinical studies: Focusing on autophagy and AMPK/mTOR signaling pathways

Metformin (MET) is a preferred drug for the treatment of type 2 diabetes mellitus. Recent studies show that apart from its blood glucose-lowering effects, it also inhibits the development of various tumours, by inducing autophagy. Various studies have confirmed the inhibitory effects of MET on cancer cell lines' propagation, migration, and invasion. The objective of the study was to comprehensively review the potential of MET as an anticancer agent, particularly focusing on its ability to induce autophagy and inhibit the development and progression of various tumors. The study aimed to explore the inhibitory effects of MET on cancer cell proliferation, migration, and invasion, and its impact on key signaling pathways such as adenosine monophosphate-activated protein kinase (AMPK), mammalian target of rapamycin (mTOR), and PI3K. This review noted that MET exerts its anticancer effects by regulating key signalling pathways such as phosphoinositide 3-kinase (PI3K), LC3-I and LC3-II, Beclin-1, p53, and the autophagy-related gene (ATG), inhibiting the mTOR protein, downregulating the expression of p62/SQSTM1, and blockage of the cell cycle at the G0/G1. Moreover, MET can stimulate autophagy through pathways associated with the 5' AMPK, thereby inhibiting he development and progression of various human cancers, including hepatocellular carcinoma, prostate cancer, pancreatic cancer, osteosarcoma, myeloma, and non-small cell lung cancer. In summary, this detailed review provides a framework for further investigations that may appraise the autophagy-induced anticancer potential of MET and its repurposing for cancer treatment.

Autophagy in cancer immunotherapy: Perspective on immune evasion and cell death interactions

Both the innate and adaptive immune systems work together to produce immunity. Cancer immunotherapy is a novel approach to tumor suppression that has arisen in response to the ineffectiveness of traditional treatments like radiation and chemotherapy. On the other hand, immune evasion can diminish immunotherapy's efficacy. There has been a lot of focus in recent years on autophagy and other underlying mechanisms that impact the possibility of cancer immunotherapy. The primary feature of autophagy is the synthesis of autophagosomes, which engulf cytoplasmic components and destroy them by lysosomal degradation. The planned cell death mechanism known as autophagy can have opposite effects on carcinogenesis, either increasing or decreasing it. It is autophagy's job to maintain the balance and proper functioning of immune cells like B cells, T cells, and others. In addition, autophagy controls whether macrophages adopt the immunomodulatory M1 or M2 phenotype. The ability of autophagy to control the innate and adaptive immune systems is noteworthy. Interleukins and chemokines are immunological checkpoint chemicals that autophagy regulates. Reducing antigen presentation to induce immunological tolerance is another mechanism by which autophagy promotes cancer survival. Therefore, targeting autophagy is of importance for enhancing potential of cancer immunotherapy.

Global research status and frontiers on autophagy in hepatocellular carcinoma: a comprehensive bibliometric and visualized analysis

BACKGROUND

An extensive body of research has explored the role of autophagy in hepatocellular carcinoma (HCC), revealing its critical involvement in the disease's pathogenesis, progression, and therapeutic targeting. However, there is a discernible deficit in quantitative, analytical studies concerning autophagy in the context of HCC. Accordingly, this investigation endeavored to meticulously assess the evolution of autophagy research, employing bibliometric citation analysis to offer a comprehensive evaluation of the findings in this field.

METHODS

The authors conducted a literature search on 2 August 2023, to extract relevant publications spanning from 2013 to 2022, indexed in the Science Citation Index-Expanded (SCIE) of the Web of Science Core Collection (WOSCC). Subsequently, the authors performed a bibliometric assessment of the compiled documents using visualization tools such as CiteSpace and VOSviewer.

RESULTS

The search yielded 734 publications penned by 4699 authors, encompassing contributions from 41 countries and 909 institutions, disseminated across 272 journals, and comprising 26 295 co-cited references from 2667 journals. Notably, China led in publication volume with 264 articles (amounting to 35.9%) and exhibited the most robust collaboration with the United States. The mechanisms underlying autophagy's influence on the emergence and advancement of HCC, as well as the implicated proteins and genes, have garnered significant attention. In recent years, investigations of targeting autophagy and the resistance to sorafenib have surfaced as pivotal themes and emerging frontiers in this domain.

CONCLUSIONS

This study rigorously collated and distilled the prevailing research narratives and novel insights on autophagy in HCC. The resultant synthesis provides a substantive foundation for medical professionals and researchers, as well as pivotal implications for future investigative endeavors in this arena.

CREB3L4 promotes hepatocellular carcinoma progression and decreases sorafenib chemosensitivity by promoting RHEB-mTORC1 signaling pathway

This study was designed to explore the roles of CREB3L4 in the pathogenesis and drug resistance of hepatocellular carcinoma (HCC). The proliferation of HCC lines was determined in the presence of CREB3L4 over-expression and silencing. Chromatin immunoprecipitation (ChIP) assay and dual-luciferase reporter assay were performed to screen the potential target of CREB3L4 on mTORC1. Xenografted tumor model was established to define the regulatory effects of CREB3L4 in the tumorigenesis. Then we evaluated the roles of CREB3L4 in chemosensitivity to sorafenib treatment. CREB3L4 significantly induced the HCC cell proliferation by modulating the activation of mTROC1-S6K1 signaling pathway via binding with RHEB promoter. Moreover, CREB3L4 dramatically inhibited the chemosensitivity to sorafenib treatment via up-regulating RHEB-mTORC1 signaling. CREB3L4 promoted HCC progression and decreased its chemosensitivity to sorafenib through up-regulating RHEB-mTORC1 signaling pathway, indicating a potential treatment strategy for HCC through targeting CREB3L4.

Mechanistic Insights about Sorafenib-, Valproic Acid- and Metformin-Induced Cell Death in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is among the main causes of death by cancer worldwide, representing about 80-90% of all liver cancers. Treatments available for advanced HCC include atezolizumab, bevacizumab, sorafenib, among others. Atezolizumab and bevacizumab are immunological options recently incorporated into first-line treatments, along with sorafenib, for which great treatment achievements have been reached. However, sorafenib resistance is developed in most patients, and therapeutical combinations targeting cancer hallmark mechanisms and intracellular signaling have been proposed. In this review, we compiled evidence of the mechanisms of cell death caused by sorafenib administered alone or in combination with valproic acid and metformin and discussed them from a molecular perspective.

Molecular Targeted Therapies in Glioblastoma Multiforme: A Systematic Overview of Global Trends and Findings

This systematic review assesses current molecular targeted therapies for glioblastoma multiforme (GBM), a challenging condition with limited treatment options. Using PRISMA methodology, 166 eligible studies, involving 2526 patients (61.49% male, 38.51% female, with a male-to-female ratio of 1.59/1), were analyzed. In laboratory studies, 52.52% primarily used human glioblastoma cell cultures (HCC), and 43.17% employed animal samples (mainly mice). Clinical participants ranged from 18 to 100 years, with 60.2% using combined therapies and 39.8% monotherapies. Mechanistic categories included Protein Kinase Phosphorylation (41.6%), Cell Cycle-Related Mechanisms (18.1%), Microenvironmental Targets (19.9%), Immunological Targets (4.2%), and Other Mechanisms (16.3%). Key molecular targets included Epidermal Growth Factor Receptor (EGFR) (10.8%), Mammalian Target of Rapamycin (mTOR) (7.2%), Vascular Endothelial Growth Factor (VEGF) (6.6%), and Mitogen-Activated Protein Kinase (MEK) (5.4%). This review provides a comprehensive assessment of molecular therapies for GBM, highlighting their varied efficacy in clinical and laboratory settings, ultimately impacting overall and progression-free survival in GBM management.

Targeting EGFR/PI3K/AKT/mTOR Signaling in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) poses a significant global health concern, with its incidence steadily increasing. The development of HCC is a multifaceted, multi-step process involving alterations in various signaling cascades. In recent years, significant progress has been made in understanding the molecular signaling pathways that play central roles in hepatocarcinogenesis. In particular, the EGFR/PI3K/AKT/mTOR signaling pathway in HCC has garnered renewed attention from both basic and clinical researchers. Preclinical studies in vitro and in vivo have shown the effectiveness of targeting the key components of this signaling pathway in human HCC cells. Thus, targeting these signaling pathways with small molecule inhibitors holds promise as a potential therapeutic option for patients with HCC. In this review, we explore recent advancements in understanding the role of the EGFR/PI3K/AKT/mTOR signaling pathway in HCC and assess the effectiveness of targeting this signaling cascade as a potential strategy for HCC therapy based on preclinical studies.

The Emerging Role of Metformin in the Treatment of Hepatocellular Carcinoma: Is There Any Value in Repurposing Metformin for HCC Immunotherapy?

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths worldwide. There has been significant progress in understanding the risk factors and epidemiology of HCC during the last few decades, resulting in efficient preventative, diagnostic and treatment strategies. Type 2 diabetes mellitus (T2DM) has been demonstrated to be a major risk factor for developing HCC. Metformin is a widely used hypoglycemic agent for patients with T2DM and has been shown to play a potentially beneficial role in improving the survival of patients with HCC. Experimental and clinical studies evaluating the outcomes of metformin as an antineoplastic drug in the setting of HCC were reviewed. Pre-clinical evidence suggests that metformin may enhance the antitumor effects of immune checkpoint inhibitors (ICIs) and reverse the effector T cells' exhaustion. However, there is still limited clinical evidence regarding the efficacy of metformin in combination with ICIs for the treatment of HCC. We appraised and analyzed in vitro and animal studies that aimed to elucidate the mechanisms of action of metformin, as well as clinical studies that assessed its impact on the survival of HCC patients.

Qingyihuaji Formula promotes apoptosis and autophagy through inhibition of MAPK/ERK and PI3K/Akt/mTOR signaling pathway on pancreatic cancer in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Qingyihuaji Formula (QYHJ), a widely used traditional Chinese medicine (TCM), has been used to treat patients with cancer in China. However, the effect and mechanism of QYHJ on pancreatic ductal adenocarcinoma (PDAC) remains unclear.

AIM OF THE STUDY

This study aimed to explore the roles and evaluate the possible underlying molecular mechanisms of QYHJ and its core component in PDAC using label-free quantitative proteomics in conjunction with network pharmacology-based analysis.

MATERIALS AND METHODS

By screening differentially expressed proteins (DEPs) in proteomics and QYHJ-predicted gene sets, we identified QYHJ-related PDAC targets annotated with bioinformatic analysis. A subcutaneous tumor model was established to assess the role of QYHJ in vivo. The effects of quercetin (Que), a core component of QYHJ, on cell proliferation, migration, invasion, apoptosis, and autophagy in SW1990 and PANC-1 cells were investigated in vitro. Immunohistochemistry, western blotting, mRFP-GFP-LC3 adenovirus, and kinase analysis were used to determine the underlying mechanisms.

RESULTS

Bioinformatics analysis revealed that 41 QYHJ-related PDAC targets were closely related to the cellular response to nitrogen compounds, positive regulation of cell death, regulation of epithelial cell apoptotic processes, and chemokine signaling pathways. CASP3, SRC, STAT1, PTPN11, PKM, and PAK1 with high expression were identified as hub DEPs in the PPI network, and these DEPs were associated with poor overall survival and STAT 1, MAPK/ERK, and PI3K/Akt/mTOR signaling pathways in PDAC patients. QYHJ significantly promoted tumor death in nude mice. Moreover, quercetin inhibited the proliferation, migration, and invasion of PDAC cells. Additionally, Que induced apoptosis and autophagy in PDAC cells. Mechanistically, QYHJ and Que significantly activated STAT 1 and remarkably inhibited the MAPK/ERK and PI3K/Akt/mTOR signaling pathways in vivo and in vitro, respectively. Importantly, ERK1/2 inactivation contributes to que-induced apoptosis in SW1990 and PANC-1 cells.

CONCLUSIONS

These results suggest that QYHJ and Que are promising anti-PDAC avenues that benefit from their multiform mechanisms.

Potential Treatment Strategies for Hepatocellular Carcinoma Cell Sensitization to Sorafenib

Liver cancer is highly malignant, has a low sensitivity to chemotherapy, and is associated with poor patient prognosis. The last 3 years have seen the emergence of promising targeted therapies for the treatment of hepatocellular carcinoma (HCC). For over 10 years, before the discovery of lenvatinib, sorafenib was only first-line therapeutic agent available for the treatment of advanced HCC. However, several clinical studies have shown that a considerable proportion liver cancer patients are insensitive to sorafenib. Very few patients actually substantially benefit from treatment with sorafenib, and the overall efficacy of the drug has not been satisfactory; therefore, sorafenib has attracted considerable research attention. This study, which is based on previous studies and reports, reviews the potential mechanisms underlying sorafenib resistance and summarizes combination therapies and potential drugs that can be used to sensitize HCC cells to sorafenib.

CPLX2 Regulates Ferroptosis and Apoptosis Through NRF2 Pathway in Human Hepatocellular Carcinoma Cells

Understanding the principle of regulated cell death (RCD) such as ferroptosis and apoptosis provides opportunities to overcome sorafenib resistance of HCC. Complexin II (CPLX2) is involved in calcium-dependent fusion of vesicles and plasma membrane, and recent studies showed CPLX2 is involved in cancer progression. However, the expression and function of CPLX2 are unclear in hepatocellular carcinoma (HCC). qPCR and western blotting assays were used to detect the levels of CPLX2. MTT and colony formation assays were used to detect cell viability. The contents of iron, ROS, MDA, and GSH were used to evaluate the function of CPLX2 on ferroptosis, while the flow cytometry and TUNEL assays were used to evaluate the role of CPLX2 on apoptosis. Our analysis showed CPLX2 is significantly upregulated in HCC, which predicts poor overall survival (OS), progression-free survival (PFS), relapse-free survival (RFS), and disease-specific survival (DSS) for patients with HCC. Further function enrichment analysis of genes related to CPLX2 showed CPLX2 is involved in the NRF2 pathway. Downregulation of CPLX2 can inhibit NRF2 expression and the transcription of its downstream genes, which confirms that CPLX2 is involved in NRF2 pathway. Cell viability assay showed that ferroptosis and apoptosis inhibitors can reverse the inhibition effect of CPLX2-knockdown on cell survival, respectively. And downregulation of CPLX2 significantly promotes the contents of iron, ROS, and MDA, while inhibiting the GSH level of HCC cell lysate, suggesting CPLX2 involved in ferroptosis. Moreover, downregulation of CPLX2 promotes the apoptosis of HCC cells by flow cytometry and TUNEL assay. And upregulation of NRF2 can partly reverse the inhibitory effect of CPLX2-downregulation on ferroptosis and apoptosis. Finally, we found downregulation of CPLX2 aggravates cell death induced by sorafenib. CPXL2 regulates ferroptosis and apoptosis through NRF2 pathway, and CPLX2 knockdown promotes cell death induced by sorafenib. CPLX2 might be an effective target for therapy patients with HCC.

Metformin administration is associated with enhanced response to transarterial chemoembolization for hepatocellular carcinoma in type 2 diabetes patients

Transarterial chemoembolization (TACE) is often used as a locoregional therapy for early hepatocellular carcinoma (HCC) when local ablation or resection are not feasible, but incomplete response and recurrence are commonly observed. In this study, we sought to determine the association between metformin administration and TACE outcomes for single nodular HCC in patients with type 2 diabetes mellitus (T2DM). The retrospective cohort analysis included 164 T2DM patients with single nodular HCC who underwent TACE as an initial treatment, and 91 were exposed to metformin before and after TACE. Propensity score (PS) matching was used to balance covariates. Logistic regression analysis was used to determine the predictors of tumor response after TACE, and Cox regression analysis assessed independent predictors of local tumor recurrence (LTR) in patients with complete response after TACE. Metformin use was associated with significantly higher objective response rate (ORR) in the overall and PS-matched cohort (79.1% vs. 60.3 and 78.7% vs. 57.5%; p = 0.008 and p = 0.029, respectively). Logistic regression analysis showed that metformin use was an independent predictor of ORR in all and PS-matched patients (odds ratio = 2.65 and 3.06; p = 0.016 and 0.034, respectively). Cox regression analysis showed metformin administration was an independent predictor for lower LTR in all and PS-matched patients (hazard ratio = 0.28 and 0.27; p = 0.001 and 0.007, respectively). Metformin administration is associated with better initial response and lower local recurrence after TACE for single nodular HCC in T2DM.

Metformin Enhances the Anti-Cancer Efficacy of Sorafenib via Suppressing MAPK/ERK/Stat3 Axis in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) incidence, as well as related mortality, has been steadily increasing in the USA and across the globe, partly due to the lack of effective therapeutic options for advanced HCC. Though sorafenib is considered standard-of-care for advanced HCC, it only improves median survival by a few months when compared to placebo. Sorafenib is also associated with several unpleasant side effects that often lead to early abatement of therapy. Here, we investigate whether a combination regimen including low-dose sorafenib and a non-toxic dose of anti-diabetic drug metformin can achieve effective inhibition of HCC. Indeed, combining metformin with low-dose sorafenib inhibited growth, proliferation, migration, and invasion potential of HCC cells. We observed a 5.3- and 1.9-fold increase in sub-G1 population in the combination treatment compared to sorafenib alone. We found that the combination of metformin enhanced the efficacy of sorafenib and inhibited the MAPK/ERK/Stat3 axis. Our in vivo studies corroborated the in vitro findings, and mice harboring HepG2-derived tumors showed effective tumor reduction upon treatment with low-dose sorafenib and metformin combination. This work sheds light on a therapeutic strategy aiming to augment sorafenib efficacy or dose-de-escalation that may prove beneficial in circumventing sorafenib resistance as well as minimizing related side effects.

Metformin Enhancement of Therapeutic Effects of 5-Fluorouracil and Oxaliplatin in Colon Cancer Cells and Nude Mice

Studies have demonstrated that metformin has antitumor effects in addition to therapeutic effects on hyperglycemia; however, few studies have explored the effects of metformin in chemotherapy. Therefore, we hypothesized that the administration of metformin would enhance the therapeutic effects of 5-fluorouracil and oxaliplatin (FuOx) to inhibit the growth of colorectal cancer (CRC) cells in vitro and in vivo. The results of our in vitro experiments demonstrated that metformin significantly increased the effects of FuOx with respect to cell proliferation (p < 0.05), colony formation (p < 0.05), and migration (p < 0.01) and induced cell cycle arrest in the G0/G1 phase in HT29 cells and the S phase in SW480 and SW620 cells (p < 0.05). Flow cytometry analysis revealed that metformin combined with FuOx induced late apoptosis (p < 0.05) by mediating mitochondria-related Mcl-1 and Bim protein expression. Furthermore, in vivo, metformin combined with FuOx more notably reduced tumor volume than FuOx or metformin alone did in BALB/c mice (p < 0.05). These findings demonstrate that metformin may act as an adjunctive agent to enhance the chemosensitivity of CRC cells to FuOx. However, further clinical trials are warranted to validate the clinical implications of the findings.

Effects of Metformin Combined With Antifolates on HepG2 Cell Metabolism and Cellular Proliferation

Hepatocellular carcinoma (HCC), one of the most prevalent types of cancers worldwide, continues to maintain high levels of resistance to standard therapy. As clinical data revealed poor response rates, the need for developing new methods has increased to improve the overall wellbeing of patients with HCC. Furthermore, a growing body of evidence shows that cancer metabolic changes are a key feature of many types of human malignancies. Metabolic reprogramming refers to cancer cells’ ability to change their metabolism in order to meet the increased energy demand caused by continuous growth, rapid proliferation, and other neoplastic cell characteristics. For these reasons, metabolic pathways may become new therapeutic and chemopreventive targets. The aim of this study was to investigate the metabolic alterations associated with metformin (MET), an anti-diabetic agent when combined with two antifolate drugs: trimethoprim (TMP) or methotrexate (MTX), and how metabolic changes within the cancer cell may be used to increase cellular death. In this study, single drugs and combinations were investigated using in vitro assays including cytotoxicity assay (MTT), RT-qPCR, annexin V/PI apoptosis assay, scratch wound assay and Seahorse XF analysis, on a human HCC cell line, HepG2. The cytotoxicity assay showed that the IC₅₀ of MET as single therapy was 44.08 mM that was reduced to 22.73 mM and 29.29 mM when combined with TMP and MTX, respectively. The co-treatment of both drugs increased p53 and Bax apoptotic markers, while decreased the anti-apoptotic marker; Bcl-2. Both combinations increased the percentage of apoptotic cells and halted cancer cell migration when compared to MET alone. Furthermore, both combinations decreased the MET-induced increase in glycolysis, while also inducing mitochondrial damage, altering cancer cell bioenergetics. These findings provide an exciting insight into the anti-proliferative and apoptotic effects of MET and anti-folates on HepG2 cells, and how in combination, may potentially combat the aggressiveness of HCC.

Sorafenib-Induced Autophagy Promotes Glycolysis by Upregulating the p62/HDAC6/HSP90 Axis in Hepatocellular Carcinoma Cells

Sorafenib has attracted much attention as the first drug approved by the FDA for the treatment of advanced hepatocellular carcinoma (HCC). Because of the drug tolerance, the overall outcomes were far from satisfactory. Current studies suggest that changes in glucose metabolism induced by sorafenib are the pivotal resistant mechanism of HCC cells, but the specific regulatory mechanism remains unclear, which makes it difficult to increase drug sensitivity by targeting glycolysis. As a metabolic-recycling pathway, autophagy regulates multiple important pathways involved in cell survival and death. In this study, we found the expression of key autophagy proteins were closely related to the prognosis and progression of HCC patients. Based on in vitro experiments, our studies showed sorafenib induced autophagy in HCC cells. Inhibition of autophagy by chloroquine could significantly increase the sensitivity of HCC cells to sorafenib and reverse the enhancement of glycolysis. Furthermore, sorafenib-induced autophagy promoted the deacetylase activity of HDAC6 by degrading p62, which promoted the activity of PKM2 by regulating the acetylation of its critical substrate HSP90. In this study, we investigated the role of autophagy-induced HDAC6 in regulating the key glycolytic enzyme PKM2, which may be helpful to clarify the relationship between autophagy and glycolysis in a sorafenib-resistant mechanism. Targeting p62/HDAC6/HSP90 could herald a potential improvement in HCC therapy.

The effects of Sorafenib and Natural killer cell co-injection in combinational treatment of hepatocellular carcinoma; an in vivo approach

BACKGROUND

Natural killer cells (NKC) and Sorafenib (Sor) are two important agents for the treatment of hepatocellular carcinoma (HCC). Over the past decade, the interaction of Sor and NKC against HCC has been widely challenging. This study aimed to assess the efficacy of NKC & Sor for the treatment of HCC in vivo.

METHODS

Subcutaneous xenograft models of HCC were established in nude mice. For safety assessment of treatment, the kidney and liver functions were analyzed. Paraffin embedded tumor sections were histopathologically studied and immunohistochemistry (IHC) tests were done to evaluate the angiogenesis (CD34) and proliferation (Ki67) indexes. The terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was performed to identify the tumor cells undergoing apoptosis. The serum levels of tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) were measured by enzyme-linked immunosorbent assay (ELISA) and expression levels of major inflammatory cytokines and cytoplasmic granules in xenograft HCC were quantified using real-time PCR.

RESULTS

NKC & Sor significantly inhibited necrosis and apoptosis in tumor cells and increased angiogenesis and proliferation of HCC compared to the monotherapy of NKC or Sor alone. The serum levels of TNF-α, IFN-γ as well as the expression levels of TNF-α, IFN-γ, interleukins (ILs)-1, 6, 10, granzyme-B and perforin in the xenograft HCC tissues of the treated mice with NKC & Sor were significantly lower than those of treated with NKC or Sor alone.

CONCLUSION

Therapy with the specific dosage of NKC & Sor could not inhibit the HCC xenograft growth rate through a synergistic effect in a mouse model of HCC.

Transarterial chemoembolization combined with metformin improves the prognosis of hepatocellular carcinoma patients with type 2 diabetes

OBJECTIVE

The study aims to investigate the effect of metformin on Hepatocellular carcinoma (HCC) patients with type 2 diabetes mellitus (T2DM) who received transarterial chemoembolization (TACE) for the first time.

METHODS

From January 2016 to December 2019, T2DM patients diagnosed with HCC in Shandong Cancer Hospital and treated with TACE were included in this retrospective study. Overall survival (OS) and Progression-free survival (PFS) were compared between patients treated with metformin and other antidiabetics. Univariate and multivariate Cox regression models were used to evaluate the independent risk factors associated with OS and PFS. And sub-analysis was performed to investigate whether metformin could give a survival advantage in each Barcelona Clinic Liver Cancer (BCLC) stage of HCC. Propensity score matched (PSM) analyses based on patient and tumor characteristics were also conducted.

RESULTS

A total of 123 HCC patients with T2DM underwent TACE, of which 50 (40.65%) received treatment with metformin. For the whole cohort, the median OS (42 vs 32 months, p=0.054) and PFS (12 vs 7 months, P=0.0016) were longer in the metformin group than that in the non-metformin group. Multi-analysis revealed that BCLC stage, BMI (Body Mass Index), and metformin use were independent predictors of OS. Metformin use was independently associated with recurrence. After PSM, 39 matched pairs were identified. The use of metformin was associated with a numerically longer m OS (43 vs 35 months, P=0.183) than the use of other anti-diabetics. And the difference in median PFS (13 vs 7 months, p=0.018) between the metformin group and non-metformin group remained significant.

CONCLUSION

The combination of transarterial chemoembolization and metformin may be associated with better OS and PFS in HCC patients with T2DM.

Magnesium demethylcantharidate inhibits hepatocellular carcinoma cell invasion and metastasis via activation transcription factor FOXO1

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in the world, develops rapidly and has a high mortality rate. Relapsed metastasis is the most important factor affecting prognosis and is also the main cause of death for patients with HCC. Cantharidin is a kind of folk medicine for malignant tumors in China. Because of its cytotoxicity, the application of cantharidin is very limited. Magnesium demethylcantharidate (MDC) is a derivative of cantharidin independently developed by our laboratory. Our results show that MDC has anticancer activity and exhibited lower toxicity than cantharidin. However, whether MDC affects the invasion and metastasis of HCC cells and the underlying molecular mechanisms remain obscure. Transwell and Matrigel assays showed that MDC could effectively inhibit the invasion and metastasis of the HCC cell lines SMMC-7721 and SK-Hep1 in a dose-dependent manner. Moreover, MDC significantly inhibited the expression of invasion and metastasis related proteins MMP-2 and MMP-9. In addition, our study found that MDC inhibited the invasion and metastasis of HCC cell lines SMMC-7721 and SK-Hep1 by activating transcription factor FOXO1. Interestingly, the combination of MDC and sorafenib significantly inhibited the invasion and metastasis of HCC cell lines SMMC-7721 and SK-Hep1 compared with the single drug treatment via the activated transcription factor FOXO1. Our work revealed that MDC obviously inhibited the invasion and metastasis of HCC cells, and suggested that MDC could be a potential candidate molecule against the invasion and metastasis of HCC.

Sorafenib prevents the proliferation and induces the apoptosis of liver cancer cells by regulating autophagy and hypoxia-inducible factor-1

Sorafenib has been approved as a systemic drug for advanced liver cancer; however, the underlying mechanisms remain unclear. The present study aimed to investigate the effects of sorafenib on the proliferation, autophagy and apoptosis of HepG2 cells under hypoxia. Briefly, reverse transcription-quantitative PCR and western blotting was performed to quantify HIF-1, LC3II/I, mTOR and p70s6K expression levels. Cell proliferation was determined using the Cell Counting Kit-8 assay and the cell apoptosis rate was evaluated using flow cytometry. The results demonstrated that autophagy and apoptosis were induced by hypoxia, and that sorafenib further enhanced hypoxia-induced autophagy and apoptosis in HepG2 cells in a dose-dependent manner. Furthermore, the mechanism of sorafenib-mediated autophagy in liver cancer cell were investigated by using chloroquine (CQ). The results showed that CQ significantly inhibited autophagy by decreasing LC3II/LC3I ratio in HepG2 cells treated with sorafenib and/or hypoxia. By contrast, sorafenib could increase the expression of hypoxia-inducible factor-1 (HIF-1) and of the autophagy marker (LC3II/I) and decrease the expression of mammalian target of rapamycin and p70 ribosomal S6 kinase in HepG2 cells under normoxia and hypoxia conditions, suggesting that sorafenib could induce hypoxia and autophagy in liver cancer cells. In addition, sorafenib was demonstrated to prevent proliferation and induce apoptosis of HepG2 cells under normoxia and hypoxia. Sorafenib could also prevent the malignant behavior of HepG2 by inducing hypoxia and autophagy. In summary, the findings from the present study suggested that sorafenib may inhibit liver cancer progression by activating autophagy and HIF-1 signaling pathway.

Clinical Characteristics of Long-Term Survivors After Sorafenib Treatment for Unresectable Hepatocellular Carcinoma: A Korean National Multicenter Retrospective Cohort Study

Background/Aim

Sorafenib is the first systemic therapy for the treatment of advanced-stage hepatocellular carcinoma (HCC) and progressive HCC after locoregional therapy. The aim of this study was to evaluate the prognostic factors of long-term survivors after sorafenib treatment.

Methods

This multicenter, retrospective, cohort study included 1,566 unresectable HCC patients who received sorafenib treatment between 2007 and 2014 in nine tertiary centers in Korea. The patients were classified into a long-term survivor group (survival more than two years, n = 257) or a control group (n = 1309). The primary outcomes were the prognostic factors affecting long-term survival. Secondary endpoints included time-to-progression and other safety profiles.

Results

The patients were predominantly men (83.8%) with chronic hepatitis B (77.3%) and Barcelona clinic of liver cancer-stage C (BCLC-C) (78.3%). The median overall survival was 9.0 months. After treatment, eight patients (0.4%) achieved complete response and 139 patients (8.8%) achieved partial response according to the mRECIST criteria. The prognostic factors predicting long-term survival were metformin use (adjusted hazard ratio [aHR] = 3.464; P < 0.001), hand-foot skin reaction (aHR = 1.688; P = 0.003), and concomitant treatment with chemoembolization or radiotherapy (aHR = 2.766; P < 0.001). Poor prognostic factors of long-term survival were a Child-Pugh score of B (HR = 0.422; P < 0.001), the presence of extrahepatic metastasis (HR = 0.639; P = 0.005), main portal vein invasion (HR = 0.502; P = 0.001), and elevated alpha-fetoprotein (>1,000 ng/mL; HR = 0.361; P < 0.001).

Conclusion

This large, multicenter, retrospective study showed an objective response rate of 9.1% and a proportion of long-term survivors of 16.4% in Korean patients. The prognostic factors derived in our study can be used in clinical practice during sorafenib treatment.

Drug-Drug Interaction between Metformin and Sorafenib Alters Antitumor Effect in Hepatocellular Carcinoma Cells

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy and is one of the leading causes of cancer-related deaths worldwide. The multitarget inhibitor sorafenib is a first-line treatment of patients with advanced unresectable HCC. Recent clinical studies have evidenced that patients treated with sorafenib together with the antidiabetic drug metformin have a survival disadvantage compared with patients receiving sorafenib only. Here, we examined whether a clinically relevant dose of metformin (50 mg/kg per day) could influence the antitumoral effects of sorafenib (15 mg/kg per day) in a subcutaneous xenograft model of human HCC growth using two different sequences of administration, i.e., concomitant versus sequential dosing regimens. We observed that the administration of metformin 6 hours prior to sorafenib was significantly less effective in inhibiting tumor growth (15.4% tumor growth inhibition) than concomitant administration of the two drugs (59.5% tumor growth inhibition). In vitro experiments confirmed that pretreatment of different human HCC cell lines with metformin reduced the effects of sorafenib on cell viability, proliferation, and signaling. Transcriptomic analysis confirmed significant differences between xenografted tumors obtained under the concomitant and the sequential dosing regimens. Taken together, these observations call into question the benefit of parallel use of metformin and sorafenib in patients with advanced HCC and diabetes, as the interaction between the two drugs could ultimately compromise patient survival. SIGNIFICANCE STATEMENT: When drugs are administered sequentially, metformin alters the antitumor effect of sorafenib, the reference treatment for advanced hepatocellular carcinoma, in a preclinical murine xenograft model of liver cancer progression as well as in hepatic cancer cell lines. Defective activation of the AMP-activated protein kinase pathway as well as major transcriptomic changes are associated with the loss of the antitumor effect. These results echo recent clinical work reporting a poorer prognosis for patients with liver cancer who were cotreated with metformin and sorafenib.

Dairy consumption and hepatocellular carcinoma risk

This review provides epidemiological and translational evidence for milk and dairy intake as critical risk factors in the pathogenesis of hepatocellular carcinoma (HCC). Large epidemiological studies in the United States and Europe identified total dairy, milk and butter intake with the exception of yogurt as independent risk factors of HCC. Enhanced activity of mechanistic target of rapamycin complex 1 (mTORC1) is a hallmark of HCC promoted by hepatitis B virus (HBV) and hepatitis C virus (HCV). mTORC1 is also activated by milk protein-induced synthesis of hepatic insulin-like growth factor 1 (IGF-1) and branched-chain amino acids (BCAAs), abundant constituents of milk proteins. Over the last decades, annual milk protein-derived BCAA intake increased 3 to 5 times in Western countries. In synergy with HBV- and HCV-induced secretion of hepatocyte-derived exosomes enriched in microRNA-21 (miR-21) and miR-155, exosomes of pasteurized milk as well deliver these oncogenic miRs to the human liver. Thus, milk exosomes operate in a comparable fashion to HBV- or HCV- induced exosomes. Milk-derived miRs synergistically enhance IGF-1-AKT-mTORC1 signaling and promote mTORC1-dependent translation, a meaningful mechanism during the postnatal growth phase, but a long-term adverse effect promoting the development of HCC. Both, dietary BCAA abundance combined with oncogenic milk exosome exposure persistently overstimulate hepatic mTORC1. Chronic alcohol consumption as well as type 2 diabetes mellitus (T2DM), two HCC-related conditions, increase BCAA plasma levels. In HCC, mTORC1 is further hyperactivated due to RAB1 mutations as well as impaired hepatic BCAA catabolism, a metabolic hallmark of T2DM. The potential HCC-preventive effect of yogurt may be caused by lactobacilli-mediated degradation of BCAAs, inhibition of branched-chain α-ketoacid dehydrogenase kinase via production of intestinal medium-chain fatty acids as well as degradation of milk exosomes including their oncogenic miRs. A restriction of total animal protein intake realized by a vegetable-based diet is recommended for the prevention of HCC.

The effects of metformin on autophagy

Metformin is the first-line option for treating newly diagnosed diabetic patients and also involved in other pharmacological actions, including antitumor effect, anti-aging effect, polycystic ovarian syndrome prevention, cardiovascular action, and neuroprotective effect, etc. However, the mechanisms of metformin actions were not fully illuminated. Recently, increasing researches showed that autophagy is a vital medium of metformin playing pharmacological actions. Nevertheless, results on the effects of metformin on autophagy were inconsistent. Apart from few clinical evidences, more data focused on kinds of no-clinical models. First, many studies showed that metformin could induce autophagy via a number of signaling pathways, including AMPK-related signaling pathways (e.g. AMPK/mTOR, AMPK/CEBPD, MiTF/TFE, AMPK/ULK1, and AMPK/miR-221), Redd1/mTOR, STAT, SIRT, Na⁺/H⁺ exchangers, MAPK/ERK, PK2/PKR/AKT/ GSK3β, and TRIB3. Secondly, some signaling pathways were involved in the process of metformin inhibiting autophagy, such as AMPK-related signaling pathways (AMPK/NF-κB and other undetermined AMPK-related signaling pathways), Hedgehog, miR-570-3p, miR-142-3p, and MiR-3127-5p. Thirdly, two types of signaling pathways including PI3K/AKT/mTOR and endoplasmic reticulum (ER) stress could bidirectionally impact the effectiveness of metformin on autophagy. Finally, multiple signal pathways were reviewed collectively in terms of affecting the effectiveness of metformin on autophagy. The pharmacological effects of metformin combining its actions on autophagy were also discussed. It would help better apply metformin to treat diseases in term of mediating autophagy.

The Chemosensitizing Role of Metformin in Anti-Cancer Therapy

Chemoresistance, which leads to the failure of chemotherapy and further tumor recurrence, presents the largest hurdle for the success of anti-cancer therapy. In recent years, metformin, a widely used first-line antidiabetic drug, has attracted increasing attention for its anti-cancer effects. A growing body of evidence indicates that metformin can sensitize tumor responses to different chemotherapeutic drugs, such as hormone modulating drugs, anti-metabolite drugs, antibiotics, and DNA-damaging drugs via selective targeting of Cancer Stem Cells (CSCs), improving the hypoxic microenvironment, and by suppressing tumor metastasis and inflammation. In addition, metformin may regulate metabolic programming, induce apoptosis, reverse Epithelial to Mesenchymal Transition (EMT), and Multidrug Resistance (MDR). In this review, we summarize the chemosensitization effects of metformin and focus primarily on its molecular mechanisms in enhancing the sensitivity of multiple chemotherapeutic drugs, through targeting of mTOR, ERK/P70S6K, NF-κB/HIF-1 α, and Mitogen- Activated Protein Kinase (MAPK) signaling pathways, as well as by down-regulating the expression of CSC genes and Pyruvate Kinase isoenzyme M2 (PKM2). Through a comprehensive understanding of the molecular mechanisms of chemosensitization provided in this review, the rationale for the use of metformin in clinical combination medications can be more systematically and thoroughly explored for wider adoption against numerous cancer types.>.

4-Acetylantrocamol LT3, a New Ubiquinone from Antrodia cinnamomea, Inhibits Hepatocellular Carcinoma HepG2 Cell Growth by Targeting YAP/TAZ, mTOR, and WNT/β-Catenin Signaling

4-acetylantrocamol LT3 (4AALT3), a new ubiquinone from the mycelium of Antrodia cinnamomea (Polyporaceae), has been recently shown to possess anticancer activity. However, the detailed mechanisms of such action remain unclear. In this study, the molecular mechanisms of 4AALT3 on hepatocellular carcinoma cells (HCC) were investigated. Human hepatocellular carcinoma cell line HepG2 cells were treated with concentrations of 4AALT3. Cell viability, colony formation, and the underlying mechanisms were then analyzed by CCK-8, colony formation, qPCR, and Western blotting assays. We found that 4AALT3 significantly decreased cell viability and colony formation in a dose-dependent manner. Accordingly, 4AALT3 significantly decreased protein levels of cyclin B, E1, D1, and D3, thereby facilitating cell cycle arrest. In addition, 4AALT3 significantly suppressed the nuclear localization of Yes-associated protein (YAP)/transcriptional co-activator with PDZ-binding motif (TAZ), mammalian target of rapamycin (mTOR), and WNT/[Formula: see text]-catenin signaling pathways, all of which are well-known signaling pathways that contribute to the malignant properties of HCC. These effects are associated with activation of 5' AMP-activated protein kinase (AMPK) and autophagy. Our findings indicate that 4AALT3 exerts inhibitory effects on HepG2 cell growth via multiple signaling pathways and may be a potential agent for HCC therapy.

A CRISPR knockout negative screen reveals synergy between CDKs inhibitor and metformin in the treatment of human cancer in vitro and in vivo

Laboratory research and pharmacoepidemiology provide support for metformin as a potential antitumor agent. However, the lack of a clear understanding of the indications of metformin limits its efficacy. Here, we performed a genome-wide CRISPR knockout negative screen to identify potential targets that might synergize with metformin. Next-generation sequencing of pooled genomic DNAs isolated from surviving cells after 18 days of metformin treatment (T18) compared to those of the untreated cells at day 0 (T0) yielded candidate genes. Knockdown of a group of cyclin-dependent kinases (CDKs), including CDK1, CDK4, and CDK6, confirmed the results of the screen. Combination treatment of the CDKs inhibitor abemaciclib with metformin profoundly inhibited tumor viability in vitro and in vivo. Although cell cycle parameters were not further altered under the combination treatment, investigation of the metabolome revealed significant changes in cell metabolism, especially with regard to fatty acid oxidation, the tricarboxylic acid cycle and aspartate metabolism. Such changes appeared to be mediated through inhibition of the mTOR pathway. Collectively, our study suggests that the combination of CDKs inhibitor with metformin could be recognized as a potential therapy in future clinical applications.

Targeting Glucose Metabolism to Overcome Resistance to Anticancer Chemotherapy in Breast Cancer

Breast cancer (BC) is the most prevalent cancer in women. BC is heterogeneous, with distinct phenotypical and morphological characteristics. These are based on their gene expression profiles, which divide BC into different subtypes, among which the triple-negative breast cancer (TNBC) subtype is the most aggressive one. The growing interest in tumor metabolism emphasizes the role of altered glucose metabolism in driving cancer progression, response to cancer treatment, and its distinct role in therapy resistance. Alterations in glucose metabolism are characterized by increased uptake of glucose, hyperactivated glycolysis, decreased oxidative phosphorylation (OXPHOS) component, and the accumulation of lactate. These deviations are attributed to the upregulation of key glycolytic enzymes and transporters of the glucose metabolic pathway. Key glycolytic enzymes such as hexokinase, lactate dehydrogenase, and enolase are upregulated, thereby conferring resistance towards drugs such as cisplatin, paclitaxel, tamoxifen, and doxorubicin. Besides, drug efflux and detoxification are two energy-dependent mechanisms contributing to resistance. The emergence of resistance to chemotherapy can occur at an early or later stage of the treatment, thus limiting the success and outcome of the therapy. Therefore, understanding the aberrant glucose metabolism in tumors and its link in conferring therapy resistance is essential. Using combinatory treatment with metabolic inhibitors, for example, 2-deoxy-D-glucose (2-DG) and metformin, showed promising results in countering therapy resistance. Newer drug designs such as drugs conjugated to sugars or peptides that utilize the enhanced expression of tumor cell glucose transporters offer selective and efficient drug delivery to cancer cells with less toxicity to healthy cells. Last but not least, naturally occurring compounds of plants defined as phytochemicals manifest a promising approach for the eradication of cancer cells via suppression of essential enzymes or other compartments associated with glycolysis. Their benefits for human health open new opportunities in therapeutic intervention, either alone or in combination with chemotherapeutic drugs. Importantly, phytochemicals as efficacious instruments of anticancer therapy can suppress events leading to chemoresistance of cancer cells. Here, we review the current knowledge of altered glucose metabolism in contributing to resistance to classical anticancer drugs in BC treatment and various ways to target the aberrant metabolism that will serve as a promising strategy for chemosensitizing tumors and overcoming resistance in BC.

The combination of Biochanin A and SB590885 potentiates the inhibition of tumour progression in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is the most aggressive and frequently diagnosed malignancy of the liver. Despite aggressive therapy, life expectancy of many patients in these cases is extended by only a few months. Hepatocellular carcinoma (HCC) has a particularly poor prognosis and would greatly benefit from more effective therapies.

Methods

The CCK-8 assay and colony formation assays were used to test the cell proliferation and viability. The effects of combination Biochanin A and SB590885 on apoptosis and cell cycle arrest of HCC cells were analysed by flow cytometry. The expression of ERK MAPK and PI3K/AKT/mTOR signalling as well as apoptosis and cell cycle-related proteins in HCC cells were tested by western blotting. The HCC cell xenograft model was established to test the tumor proliferation. Serum and plasma were tested for liver and kidney safety markers (ALP, ALT, AST, total bilirubin, creatinine, urea nitrogen) by using SpectraMax i3X.

Results

The combination of natural product Biochanin A with the BRAF inhibitor SB590885 synergistically suppressed proliferation, and promoted cell cycle arrest and apoptosis in vitro. Furthermore, we demonstrated that the combination of Biochanin A and SB590885 led to increased impairment of proliferation and HCC tumour inhibition through disrupting of the ERK MAPK and the PI3K/AKT pathways in vitro. The volumes tumors and the weights of tumours were significantly reduced by the combination treatment compared to the control or single treatments in vivo. In addition, we found that there was no significant hepatorenal toxicity with the drug combination, as indicated by the hepatorenal toxicity test.

Conclusion

The results identify an effective combination therapy for the most aggressive form of HCC and provide the possibility of therapeutic improvement for patients with advanced HCC.

Curcumol enhances the anti-tumor effects of metformin via suppressing epithelial-mesenchymal transition in triple-negative breast cancer

Background

Triple-negative breast cancer (TNBC) is a severe disease with a high mortality rate. Metformin has been found to possess anti-tumor properties. Curcumol, an active ingredient extracted from curcuma, exerts the protective effect in TNBC cells through inducing apoptosis. However, the effects of curcumol combined with metformin on the treatment of TNBC have yet to be fully established.

Methods

TNBC cells MDA-MB-231 and MDA-MB-468 cells were used in the study. TNBC cells were treated with curcumol and metformin alone or treated with curcumol combined with metformin. Cell viability was determined using Cell Counting Kit-8 (CCK-8) assay. Cell apoptosis was detected using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The levels of proteins were measured using Western blot. Wound healing assay and Transwell invasion assays were used to determine cell migration and invasion ability, respectively. A xenograft model was established to investigate the tumor growth ability. Immunohistochemistry was performed to determine the expression of Ki-67 and Vascular endothelial growth factor (VEGF).

Results

In the study, the administration of curcumol alone had no significant effects on the TNBC cells. However, the anti-proliferation, anti-metastasis, and anti-epithelial-mesenchymal transition (EMT) effects of metformin were enhanced by the addition of curcumol. Further, curcumol reversed TNBC cell proliferation, migration, invasion, and EMT induced by rucaparib, and enhanced the effect of metformin on rucaparib-induced TNBC cells. The combination of curcumol and metformin also suppressed tumor growth, EMT marker expression, and the activation of Wnt2/β-Catenin signaling during in vivo experiments.

Conclusions

The combination of curcumol and metformin enhances the anti-tumor effects of metformin on TNBC via inhibiting EMT. Curcumol combined with metformin may hold promise as a therapeutic strategy for TNBC.

Metformin Induces Autophagy via the AMPK-mTOR Signaling Pathway in Human Hepatocellular Carcinoma Cells

Background

Metformin may exert the anticancer effect on multiple types of cancers and some potential mechanisms have been suggested. Our study was designed to determine the effect of metformin on the cell autophagy and autophagic flux via the AMPK-mTOR signaling pathway in human hepatocellular carcinoma (HCC) cells.

Methods

MHCC97H and HepG2 cell lines were cultured and treated without and with metformin at various concentrations (2, 5, 10 and 20 mM) for 48 h. Then, 10 mM was determined as the optimal concentration and the HCC cells were treated with metformin for 12, 24, 48, and 72 h. MTT assay was used to assess the cell viability and Western blotting was used to determine the expression of proteins (LC3-II, p62, phospho-AMPKα, phospho-mTOR, mTOR, phospho-p70 S6 Kinase, p70 S6 Kinase, PARP1, Caspase-9 and Caspase-3). Autophagy inhibitor 3-methyladenine, EGFP-LC3 and mCherry-GFP-LC3B plasmid transfection were used for further study.

Results

Metformin inhibited significantly the viability of MHCC97H and HepG2 cells in a dose- and time-dependent manner. For the apoptotic properties, activation of Caspase-9 and Caspase-3 and PARP cleavage were not observed after treatment with metformin. MHCC97H cells were transfected with a EGFP-LC3 plasmid and treatment with metformin could lead to the increased level of LC3-II and decreased level of p62. In metformin-induced autophagy, AMPK expression was activated, and the phosphorylation levels of mTOR and p70 S6 Kinase were inhibited. Metformin treatment and mCherry-GFP-LC3B plasmid transfection showed that metformin could induce the autophagic flux. 3-Methyladenine (3-MA) partly abolished this effect.

Conclusion

Metformin could induce the autophagy, autophagic flux, and activate the AMPK-mTOR signaling pathway in human HCC cells.

Pharmacokinetic Interaction between Sorafenib and Atorvastatin, and Sorafenib and Metformin in Rats

The tyrosine kinase inhibitor sorafenib is the first-line treatment for patients with hepatocellular carcinoma (HCC), in which hyperlipidemia and type 2 diabetes mellitus (T2DM) may often coexist. Protein transporters like organic cation (OCT) and multidrug and toxin extrusion (MATE) are involved in the response to sorafenib, as well as in that to the anti-diabetic drug metformin or atorvastatin, used in hyperlipidemia. Changes in the activity of these transporters may lead to pharmacokinetic interactions, which are of clinical significance. The study aimed to assess the sorafenib−metformin and sorafenib−atorvastatin interactions in rats. The rats were divided into five groups (eight animals in each) that received sorafenib and atorvastatin (I_SOR+AT), sorafenib and metformin (II_SOR+MET), sorafenib (III_SOR), atorvastatin (IV_AT), and metformin (V_MET). Atorvastatin significantly increased the maximum plasma concentration (C_max) and the area under the plasma concentration–time curve (AUC) of sorafenib by 134.4% (p < 0.0001) and 66.6% (p < 0.0001), respectively. Sorafenib, in turn, caused a significant increase in the AUC of atorvastatin by 94.0% (p = 0.0038) and its metabolites 2−hydroxy atorvastatin (p = 0.0239) and 4−hydroxy atorvastatin (p = 0.0002) by 55.3% and 209.4%, respectively. Metformin significantly decreased the AUC of sorafenib (p = 0.0065). The AUC ratio (II_SOR+MET group/III_SOR group) for sorafenib was equal to 0.6. Sorafenib did not statistically significantly influence the exposure to metformin. The pharmacokinetic interactions observed in this study may be of clinical relevance in HCC patients with coexistent hyperlipidemia or T2DM.

The mechanisms of sorafenib resistance in hepatocellular carcinoma: theoretical basis and therapeutic aspects

Sorafenib is a multikinase inhibitor capable of facilitating apoptosis, mitigating angiogenesis and suppressing tumor cell proliferation. In late-stage hepatocellular carcinoma (HCC), sorafenib is currently an effective first-line therapy. Unfortunately, the development of drug resistance to sorafenib is becoming increasingly common. This study aims to identify factors contributing to resistance and ways to mitigate resistance. Recent studies have shown that epigenetics, transport processes, regulated cell death, and the tumor microenvironment are involved in the development of sorafenib resistance in HCC and subsequent HCC progression. This study summarizes discoveries achieved recently in terms of the principles of sorafenib resistance and outlines approaches suitable for improving therapeutic outcomes for HCC patients.

Is the era of sorafenib over? A review of the literature

Hepatocellular carcinoma (HCC) is one of the most severe diseases worldwide. For the different stages of HCC, there are different clinical treatment strategies, such as surgical therapy for the early stage, and transarterial chemoembolization (TACE) and selective internal radiation therapy (SIRT) for intermediate-stage disease. Systemic treatment, which uses mainly targeted drugs, is the standard therapy against advanced HCC. Sorafenib is an important first-line therapy for advanced HCC. As a classically effective drug, sorafenib can increase overall survival markedly. However, it still has room for improvement because of the heterogeneity of HCC and acquired resistance. Scientists have reported the acquired sorafenib resistance is associated with the anomalous expression of certain genes, most of which are also related with HCC onset and development. Combining sorafenib with inhibitors targeting these genes may be an effective treatment. Combined treatment may not only overcome drug resistance, but also inhibit the expression of carcinoma-related genes. This review focuses on the current status of sorafenib in advanced HCC, summarizes the inhibitors that can combine with sorafenib in the treatment against HCC, and provides the rationale for clinical trials of sorafenib in combination with other inhibitors in HCC. The era of sorafenib in the treatment of HCC is far from over, as long as we find better methods of medication.

Combination of aloin and metformin enhances the antitumor effect by inhibiting the growth and invasion and inducing apoptosis and autophagy in hepatocellular carcinoma through PI3K/AKT/mTOR pathway

Hepatocellular carcinoma (HCC) is a devastating and highly metastatic cancer worldwide. Metformin (MET) is the priority drug for treatment of type 2 diabetes; however, it possesses multiple biological effects like anticancer and hepatoprotective activity. Herein, we examined the effects of aloin (barbaloin) and MET as well as combination treatment in HCC cell line in vitro and in vivo. As a result, aloin and MET alone exhibited inhibitory effects on proliferation and invasion of HepG2 and Bel‐7402 cells. Specially, combination treatment of aloin and MET showed enhanced inhibitory effects in vitro. Aloin and MET alone induced apoptosis and autophagy in vitro. Similarly, aloin and MET cooperated to promote apoptosis and autophagy in HepG2 and Bel‐7402 cells. In the HepG2 xenograft models, aloin in combination with MET confine tumor growth and facilitate apoptosis and autophagy. Both the in vitro and in vivo results showed that aloin and MET alone as well as combination treatment activated the PI3K/AKT/mTOR pathway. Overall, our research demonstrated that the concomitant treatment with aloin and MET enhances the antitumor effect by inhibiting the growth and invasion as well as inducing apoptosis and autophagy in HCC through PI3K/AKT/mTOR pathway.

Kaempferol promotes bone formation in part via the mTOR signaling pathway

Previous research indicates that kaempferol (Kae) promotes osteogenesis, but its underlying mechanism of action remains unclear. The present study hypothesized that the osteogenic effects of Kae were mediated through mammalian target of rapamycin (mTOR). To validate this hypothesis, bone marrow mesenchymal stem cells (BMSCs) from ovariectomized (OVX) rats were differentiated into osteoblasts. The bone mineral density and bone microarchitecture of the OVX rats was measured in vivo, while osteogenesis was evaluated in vitro via Alizarin Red S staining and alkaline phosphatase activity measurements in cultured BMSCs. The levels of phosphorylated eukaryotic translation initiation factor 4E‑binding protein 1 (p‑4E/BP1) and phosphorylated ribosomal protein S6 kinase B1 (p‑S6K), and the expression of Runt‑related transcription factor 2 and Osterix, were concurrently quantified by western blot analysis. The data suggested that Kae prevented OVX‑induced osteoporosis in rats by promoting osteoblastogenesis. Furthermore, treatment with Kae in rat BMSCs enhanced mineralization, elevated ALP activity, increased the expression levels of Runx‑2 and Osterix and increased the levels of p‑S6K and decreased the levels of p‑4E/BP1 and, consistent with its ability to promote osteoblast differentiation. In contrast, treatment with rapamycin, an mTOR inhibitor, produced the opposite phenotype. Taken together, these data suggested that the protective effects of Kae in BMSCs and in the OVX rat model resulted from the induction of osteogenesis via mTOR signaling, or at least partially via the regulation of downstream effectors of the mTOR pathway.

Sorafenib with Transarterial Chemoembolization Achieves Improved Survival vs. Sorafenib Alone in Advanced Hepatocellular Carcinoma: A Nationwide Population-Based Cohort Study

We hypothesized that sorafenib plus transarterial chemoembolization (TACE) would confer survival benefits over sorafenib alone for advanced hepatocellular carcinoma (aHCC). We investigated this while using the population-based All-Cancer Dataset to assemble a cohort (n = 3674; median age, 60; 83% men) of patients receiving sorafenib for aHCC (Child-Pugh A) with macro-vascular invasion or nodal/distant metastases. The patients were classified into the sorafenib-TACE group (n = 426) or the propensity score-matched sorafenib-alone group (n = 1686). All of the participants were followed up until death or the end of the study. Time-dependent Cox model and the Mantel-Byar test were used for survival analysis. During the median follow-ups of 221 and 133 days for the sorafenib-TACE and sorafenib-alone groups, 164 (39%) and 916 (54%) deaths occurred, respectively; the corresponding median overall survivals (OS) were 381 and 204 days, respectively (hazard ratio, HR: 0.74; 95% confidence interval, CI, 0.63-0.88; p = 0.021). The one-year and six-month OS were 53.5% and 80.3% in the sorafenib-TACE group and 32.4% and 54.4% in the sorafenib-alone group, respectively. The major complications were comparable between the two groups. The addition of TACE to sorafenib improves survival, with a 26% reduction in mortality. These findings provide strong real-world evidence that supports this combination strategy for eligible Child-Pugh A aHCC patients.

Targeted therapy for hepatocellular carcinoma: Challenges and opportunities

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, which ranks as the sixth of cancer-related death. Despite the emergence of targeted therapy, advanced-stage HCC remains largely incurable due to low response rate and therapeutic resistance. In this review, we mainly focused on the current progression of multi-kinase inhibitors and immunotherapies in the treatment of HCC. We highlight the mechanism underlying the ineffectiveness of these targeted therapies, including oncogenic alterations in driver genes and downstream pathways, high heterogeneity of HCC, and the mutual interaction of tumor microenvironment that promotes therapeutic resistance. We also discussed how these previous studies suggested for future therapeutic strategies. Besides, the complexity of HCC heterogeneity and cancer revolution need to be recognized in personalized therapy. Establishment of a drug screening system and identification of biomarkers of response is also in urgent need to overcome drug resistance. Meanwhile, a combination of targeted therapies could also be explored as a promising strategy in the future.

Role of p53 Family Proteins in Metformin Anti-Cancer Activities

Metformin has been used as therapy for type 2 diabetes for many years. Clinical and basic evidence as indicated that metformin has anti-cancer activities. It has been well-established that metformin activates AMP-activated protein kinase (AMPK), which in turn regulates energy homeostasis. However, the mechanistic aspects of metformin anti-cancer activity remain elusive. p53 family proteins, including p53, p63 and p73, have diverse biological functions, including regulation of cell growth, survival, development, senescence and aging. In this review, we highlight the evidence and mechanisms by which metformin inhibits cancer cell survival and tumor growth. We also aimed to discuss the role of p53 family proteins in metformin-mediated suppression of cancer growth and survival.

Investigation of new treatment option for hepatocellular carcinoma: a combination of sorafenib with usnic acid

Objectives

Sorafenib (SOR) is an orally administered molecular targeted agent in the systemic chemotherapy of hepatocellular carcinoma (HCC). However, the partial response of SOR is limited due to its adverse side effect and high heterogeneity and resistant phenotype of HCC. In the current study, we investigated synergistic effects of SOR and usnic acid (UA) on HCC cell lines including HepG2 and SNU-449, and a normal cell line, HUVEC.

Methods

The antiproliferative and apoptotic effects of combination therapy and SOR alone were analysed by WST-1 and Annexin V analysis, respectively. Furthermore, cell cycle, gene expression analysis of SOR-targeted kinases and acridine orange–ethidium bromide staining were also performed in combined treatments.

Key findings

Our results demonstrated that SOR and UA combination indicated a strong synergism in HCC cell lines and reduced SOR toxicity in HUVEC cells. Additionally, the combination treatment SOR and UA significantly induced much more apoptotic cell death and G0/G1 arrest through downregulation of SOR-targeted kinases.

Conclusions

Consequently, SOR and UA combination could be a new therapeutic strategy for HCC treatment.

[Tumor-associated macrophages attenuate apoptosis-inducing effect of sorafenib in hepatoma cells by increasing autophagy]

OBJECTIVE

To explore the molecular mechanism of sorafenib resistance in hepatoma cells and identify for new targets to reverse drug resistance.

METHODS

THP-1 cells were induced into M2 tumor-associated macrophages (M2-TAMs) in vitro and identified by immunofluorescence. SMMC-7721 cells were co-cultured with M2-TAMs with or without sorafenib treatment. CCK-8 assay was used to observe the inhibitory effect of sorafenib on the cell proliferation. Annexin V/PI double staining and protein immunoblotting were used to assess the effect of sorafenib on the proliferation, apoptosis and the expressions of apoptosis-related proteins and autophagy-related protein in SMMC-7721 cells co-cultured with M2-TAMs in the presence or absence of the autophagy inhibitor chloroquine (CQ).

RESULTS

The IC₅₀ of sorafenib at 48 h was 2.25 μmol/L in SMMC-7721 cells cultured alone, and increased to 4.72 μmol/L in the cells co-cultured with M2-TAMs. Compared with the cells cultured alone, the co-cultured SMMC-7721 cells showed significantly reduced apoptosis rate in response to sorafenib (P &lt; 0.01) and significantly increased expression of Bcl-2 and Bcl-2/Bax ratio (P &lt; 0.05) with also increased LC3-II/LC3-I ratio (P &lt; 0.001) and lowered expression of p62 (P &lt; 0.05), suggesting a significantly enhanced level of autophagy. CQ treatment significantly inhibited the proliferation of the co-cultured SMMC-7721 cells (P &lt; 0.05), increased the cell apoptosis (P &lt; 0.05) and reduced the Bcl-2/Bax ratio (P &lt; 0.01).

CONCLUSIONS

M2-TAMs can attenuate the inhibitory effect of sorafenib on the proliferation of hepatoma cells by increasing the level of autophagy, suggesting a new strategy for reversing sorafenib resistance induced by the tumor microenvironment by inhibiting autophagy.

Hepatoprotective activity of metformin: A new mission for an old drug?

Metformin, as a dimethyl biguanide prescribed as the first-line medication for treatment of type 2 diabetes mellitus, is one of the most frequently used drugs, worldwide. However, the beneficial effects of metformin are not limited to insulin sensitizing and blood glucose lowering effects as recent clinical trials deciphered lower cancer risk in metformin users. In addition, metformin protected the liver against chemical or viral hepatotoxicants through various mechanisms including activation of AMPK via inhibition of mitochondrial complex I, inhibition of mitogen activated protein kinase (MAPK) and inhibition of Smads phosphorylation. Clinical trials are under way to assess possible additive effects of metformin when co-administered along with the standard regimen for hepatocellular carcinoma (HCC) treatment. This review outlines the molecular mechanisms behind protective activity of metformin against different liver diseases.

Blocking Autophagy in Cancer-Associated Fibroblasts Supports Chemotherapy of Pancreatic Cancer Cells

In this study we evaluated the interaction of pancreatic cancer cells, cancer-associated fibroblasts, and distinct drugs such as α-cyano-4-hydroxycinnamate, metformin, and gemcitabine. We observed that α-cyano-4-hydroxycinnamate as monotherapy or in combination with metformin could significantly induce collagen I deposition within the stromal reaction. Subsequently, we demonstrated that cancer-associated fibroblasts impaired the anti-proliferation efficacy of α-cyano-4-hydroxycinnamate, metformin and gemcitabine. Interestingly, inhibition of autophagy in these fibroblasts can augment the anti-proliferation effect of these chemotherapeutics in vitro and can reduce the tumor weight in a syngeneic pancreatic cancer model. These results suggest that inhibiting autophagy in cancer-associated fibroblasts may contribute to strategies targeting cancer.

Novel application of metformin combined with targeted drugs on anticancer treatment

The success of targeted drug therapies for treating cancer patients has attracted broad attention both in the academic community and social society. However, rapidly developed acquired resistance is becoming a newly recognized major challenge to the continuing efficiency of these therapies. Metformin is a well‐known natural compound with low toxicity derived from the plant French lilac. Our previous work has highlighted research progress of the combination of clinically applied chemotherapies and metformin by different mechanisms. We have also launched a study to combine metformin with the small molecule targeted drug gefitinib to treat bladder cancer using intravesical administration. Thus, in this minireview, we summarize recent achievements combining metformin with various targeted therapies. This work directs the potential clinical future by selecting available cancer patients and providing precise medicine by the combination of metformin and targeted drugs to overcome resistance and enhance therapeutic efficacies.

Absence of antitumor effects of metformin in sorafenib-treated patients with hepatocellular carcinoma recurrence after hepatic resection and liver transplantation

Backgrounds/Aims

Hepatocellular carcinoma (HCC) recurrence following hepatic resection (HR) and liver transplantation (LT) remains a great concern. We assessed the antitumor effects of metformin in patients treated with sorafenib for HCC recurrence after HR or LT.

Methods

The two clinical retrospective studies involved metformin therapy of 304 HR patients and 74 LT recipients who were treated with sorafenib.

Results

In the study involving patients who had undergone HR, death occurred in 245 of the 304 patients (80.6%) during a median follow-up of 10.2 months after sorafenib administration. The metformin HR group (group 1; n=40) showed no prognostic difference in progression-free and overall survival rates compared with the all-HR control group (group 3; n=241) and propensity score-matched HR control group (group 4; n=80). In the clinical study of recipients exposed to LT, death occurred in 62 of the 74 patients (83.8%) during a median follow-up of 13.6 months (range: 3–76 months) after sorafenib administration. The metformin LT group (group 5; n=14) showed no prognostic difference in progression-free and overall survival rates compared with the all-LT control group (group 7; n=43) and propensity score-matched LT control group (group 8; n=28).

Conclusions

Our clinical studies demonstrated absence of synergistic antitumor effects of metformin. Further high-volume studies are necessary to assess the role of metformin in patients treated with sorafenib for advanced HCC.

Role of autophagy in tumorigenesis, metastasis, targeted therapy and drug resistance of hepatocellular carcinoma

Autophagy is a “self-degradative” process and is involved in the maintenance of cellular homeostasis and the control of cellular components by facilitating the clearance or turnover of long-lived or misfolded proteins, protein aggregates, and damaged organelles. Autophagy plays a dual role in cancer, including in tumor progression and tumor promotion, suggesting that autophagy acts as a double-edged sword in cancer cells. Liver cancer is one of the greatest leading causes of cancer death worldwide due to its high recurrence rate and poor prognosis. Especially in China, liver cancer has become one of the most common cancers due to the high infection rate of hepatitis virus. In primary liver cancer, hepatocellular carcinoma (HCC) is the most common type. Considering the perniciousness and complexity of HCC, it is essential to elucidate the function of autophagy in HCC. In this review, we summarize the physiological function of autophagy in cancer, analyze the role of autophagy in tumorigenesis and metastasis, discuss the therapeutic strategies targeting autophagy and the mechanisms of drug-resistance in HCC, and provide potential methods to circumvent resistance and combined anticancer strategies for HCC patients.