Bufalin inhibits hepatitis B virus-associated hepatocellular carcinoma development through androgen receptor dephosphorylation and cell cycle-related kinase degradation

Bufalin suppresses hepatocellular carcinogenesis by targeting M2 macrophage-governed Wnt1/β-catenin signaling

BACKGROUND

The interplay of tumor-associated macrophages (TAMs) and tumor cells plays a key role in the development of hepatocellular carcinoma (HCC) and provides an important target for HCC therapy. The communication between them is still on the investigation. Bufalin, the active component derived from the traditional Chinese medicine (TCM) Chansu, has been evidenced to possess anti-HCC activity by directly suppressing tumor cells, while its immunomodulatory effect on the tumor microenvironment (TME) is unclear.

PURPOSE

To explore the mechanism of M2 TAM-governed tumor cell proliferation and the inhibitory effect of bufalin on HCC growth by targeting M2 macrophages.

METHODS

Morphology and marker proteins were detected to evaluate macrophage polarization via microscopy and flow cytometry. Cellular proliferation and malignant transformation of HCC cells cultured with macrophage conditioned medium (CM) or bufalin-primed M2-CM, were assessed by cell viability, colony formation and soft agar assays. Regulations of gene transcription and protein expression and release were determined by RT-qPCR, immunoblotting, immunoprecipitation, ELISA and immunofluorescence. Tumorigenicity upon bufalin treatment was verified in orthotopic and diethylnitrosamine-induced HCC mouse model.

RESULTS

In this study, we first verified that M2 macrophages secreted Wnt1, which acted as a mediator to trigger β-catenin activation in HCC cells, leading to cellular proliferation. Bufalin suppressed HCC cell proliferation and malignant transformation by inhibiting Wnt1 release in M2 macrophages, and dose-dependently inhibited HCC progression in mice. Mechanistically, bufalin specially targeted to block Wnt1 transcription, thus inactivating β-catenin signaling cascade in HCC cells and leading to tumor regression in HCC mouse model.

CONCLUSION

These results clearly reveal a novel potential of bufalin to suppress HCC through immunomodulation, and shed light on a new M2 macrophage-based modality of HCC immunotherapy, which additively enhances direct tumor-inhibitory efficacy of bufalin.

Multi-b-value DWI to evaluate the synergistic antiproliferation and anti-heterogeneity effects of bufalin plus sorafenib in an orthotopic HCC model

BACKGROUND

Multi-b-value diffusion-weighted imaging (DWI) with different postprocessing models allows for evaluating hepatocellular carcinoma (HCC) proliferation, spatial heterogeneity, and feasibility of treatment strategies. We assessed synergistic effects of bufalin+sorafenib in orthotopic HCC-LM3 xenograft nude mice by using intravoxel incoherent motion (IVIM), diffusion kurtosis imaging (DKI), a stretched exponential model (SEM), and a fractional-order calculus (FROC) model.

METHODS

Twenty-four orthotopic HCC-LM3 xenograft mice were divided into bufalin+sorafenib, bufalin, sorafenib treatment groups, and a control group. Multi-b-value DWI was performed using a 3-T scanner after 3 weeks' treatment to obtain true diffusion coefficient Dt, pseudo-diffusion coefficient Dp, perfusion fraction f, mean diffusivity (MD), mean kurtosis (MK), distributed diffusion coefficient (DDC), heterogeneity index α, diffusion coefficient D, fractional order parameter β, and microstructural quantity μ. Necrotic fraction (NF), standard deviation (SD) of hematoxylin-eosin staining, and microvessel density (MVD) of anti-CD31 staining were evaluated. Correlations of DWI parameters with histopathological results were analyzed, and measurements were compared among four groups.

RESULTS

In the final 22 mice, f positively correlated with MVD (r = 0.679, p = 0.001). Significantly good correlations of MK (r = 0.677), α (r = -0.696), and β (r= -0.639) with SD were observed (all p < 0.010). f, MK, MVD, and SD were much lower, while MD, α, β, and NF were higher in bufalin plus sorafenib group than control group (all p < 0.050).

CONCLUSION

Evaluated by IVIM, DKI, SEM, and FROC, bufalin+sorafenib was found to inhibit tumor proliferation and angiogenesis and reduce spatial heterogeneity in HCC-LM3 models.

RELEVANCE STATEMENT

Multi-b-value DWI provides potential metrics for evaluating the efficacy of treatment in HCC.

KEY POINTS

• Bufalin plus sorafenib combination may increase the effectiveness of HCC therapy. • Multi-b-value DWI depicted HCC proliferation, angiogenesis, and spatial heterogeneity. • Multi-b-value DWI may be a noninvasive method to assess HCC therapeutic efficacy.

The role of sex hormones and receptors in HBV infection and development of HBV-related HCC

Gender disparity in hepatitis B virus (HBV)-related diseases has been extensively documented. Epidemiological studies consistently reported that males have a higher prevalence of HBV infection and incidence of hepatocellular carcinoma (HCC). Further investigations have revealed that sex hormone-related signal transductions play a significant role in gender disparity. Sex hormone axes showed significantly different responses to virus entry and replication. The sex hormones axes change the HBV-specific immune responses and antitumor immunity. Additionally, Sex hormone axes showed different effects on the development of HBV-related disease. But the role of sex hormones remains controversial, and researchers have not reached a consensus on the role of sex hormones and the use of hormone therapies in HCC treatment. In this review, we aim to summarize the experimental findings on sex hormones and provide a comprehensive understanding of their roles in the development of HCC and their implications for hormone-related HCC treatment.

Bufalin targeting BFAR inhibits the occurrence and metastasis of gastric cancer through PI3K/AKT/mTOR signal pathway

Gastric cancer (GC) is the most common malignant tumor of digestive system. Bufalin extracted from Venenum Bufonis is one of the most effective anticancer monomers, which has been proved to play anticancer roles in a variety of cancers such as ovarian cancer, prostate cancer and neuroblastoma. However, there are few studies on bufalin in GC, and lack of clear targets. The effect of bufalin on the proliferation and migration of GC cells was detected by CCK-8, scratch wound healing assay, transwell assay and Western blotting. The potential direct interaction proteins of bufalin were screened by human proteome microarray containing 21,838 human proteins. The target protein was determined by bioinformatics, and the binding sites were predicted by molecular docking technique. Biological experiments in vitro and in vivo were conducted to verify the effect of bufalin directly interaction protein and the mechanism of bufalin targeting the protein to inhibit the development of GC. The results showed that bufalin inhibited the proliferation and migration of MKN-45 and HGC-27 GC cell lines in vitro. BFAR, a direct interaction protein of bufalin has several potential binding sites to bufalin. BFAR is highly expressed in GC and promotes the occurrence and metastasis of GC by activating PI3K/AKT/mTOR signal pathway in vitro and in vivo. Bufalin reversed the promoting effect of BFAR on the carcinogenesis and metastasis of GC by down-regulating the expression of BFAR. Our results show that bufalin targeting BFAR inhibits the occurrence and metastasis of GC through PI3K/AKT/mTOR signal pathway. These results provide a new basis for bufalin as a promising drug for the treatment of GC.

Identification of Na+/K+-ATPase Inhibitor Bufalin as a Novel Pseudorabies Virus Infection Inhibitor In Vitro and In Vivo

Pseudorabies virus (PRV), an alpha herpesvirus, induces significant economic losses to the swine industry and infects multiple kinds of animals. Therefore, it is of great importance to explore anti-PRV compounds. In this study, to explore the anti-PRV compounds, a library of natural compounds was screened through a cell-based ELISA assay, and it was discovered that bufalin, a Na+/K+-ATPase inhibitor, had a robust inhibitory effect on PRV replication. A time-of-addition experiment and temperature-shift assay showed that bufalin significantly inhibited the entry stage of PRV. NaCl- or KCl-treatment showed that NaCl could enhance the inhibitory effect of bufalin on PRV replication, whereas there was no significant effect under the treatment of KCl. Meanwhile, it was also found that bufalin possessed antiviral activity against other alpha herpesviruses, including human herpes simplex virus type 1 (HSV-1) and chicken Marek's disease virus (MDV). Finally, it was found that bufalin could decrease the viral load in multiple tissues, and reduce the morbidity and mortality in PRV-challenged BALB/c mice. Overall, our findings demonstrated that bufalin has the potential to be developed as an anti-PRV compound.

Brassicasterol inhibits hepatitis B virus-associated hepatocellular carcinoma development via suppression of AKT signaling pathway

BACKGROUND

Hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) does not respond well to current treatment options like sorafenib, and there is an urgent need for developing therapeutical strategies for HBV + HCC. Brassicasterol has previously shown anti-cancer and anti-viral activities, however, its value against HBV + HCC remains to be explored.

METHODS

The inhibitory effect of brassicasterol and sorafenib was evaluated on HBV + HCC cell lines and xenograft mouse model. The cytotoxicity of brassicasterol on normal liver cells were measured by LDH assay. AKT agonist was used to identify the targeted signaling pathway by brassicasterol.

RESULTS

Brassicasterol induced HBV + HCC cell death in a both dose-dependent and time-dependent manner, and such inhibition was more potent than sorafenib. Brassicasterol did not show apparent cytotoxicity to normal liver cells. Xenograft mouse model further confirmed the inhibitory effect of brassicasterol on the growth of HBV + HCC. Furthermore, signaling pathway analysis showed that brassicasterol-treated HBV + HCC cells had decreased level of phosphor-AKT expression while the addition of AKT agonist could counteract the inhibitory effect of brassicasterol on HCC, indicating that brassicasterol suppressed AKT pathway to exhibit anti-cancer activity in HBV + HCC cells. In addition, brassicasterol showed similar levels of inhibition on HBV- and HBV + HCC cells.

CONCLUSION

Brassicasterol possesses anti-cancer activity against HCC through the downregulation of AKT pathway and such activity is independent of HBV infection.

A Selective Androgen Receptor Modulator, S4, Displays Robust Anti-cancer Activity on Hepatocellular Cancer Cells by Negatively Regulating PI3K/AKT/mTOR Signaling Pathway

Hepatocellular carcinoma (HCC) is a major global health problem that often correlates with poor prognosis. Due to the insufficient therapy options with limited benefits, it is crucial to identify new therapeutic approaches to overcome HCC. One of the vital signaling pathways in organ homeostasis and male sexual development is Androgen Receptor (AR) signaling. Its activity affects several genes that contribute to cancer characteristics and have essential roles in cell cycle progression, proliferation, angiogenesis, and metastasis. AR signaling has been shown to be misregulated in many cancers, including HCC, suggesting that it might contribute to hepatocarcinogenesis. Targeting AR signaling using anti-androgens, AR inhibitors, or AR-degrading molecules is a powerful and promising strategy to defeat HCC. In this study, AR signaling was targeted by a novel Selective Androgen Receptor Modulator (SARM), S4, in HCC cells to evaluate its potential anti-cancer effect. To date, S4 activity in cancer has not been demonstrated, and our data unrevealed that S4 significantly impaired HCC growth, migration, proliferation, and induced apoptosis through inhibiting PI3K/AKT/mTOR signaling. Since PI3K/AKT/mTOR signaling is frequently activated in HCC and contributes to its aggressiveness and poor prognosis, its negative regulation by the downregulation of critical components via S4 was a prominent finding. Further studies are necessary to investigate the S4 action mechanism and anti-tumorigenic capacity in in-vivo.

Bufalin-Mediated Regulation of Cell Signaling Pathways in Different Cancers: Spotlight on JAK/STAT, Wnt/β-Catenin, mTOR, TRAIL/TRAIL-R, and Non-Coding RNAs

The renaissance of research into natural products has unequivocally and paradigmatically shifted our knowledge about the significant role of natural products in cancer chemoprevention. Bufalin is a pharmacologically active molecule isolated from the skin of the toad Bufo gargarizans or Bufo melanostictus. Bufalin has characteristically unique properties to regulate multiple molecular targets and can be used to harness multi-targeted therapeutic regimes against different cancers. There is burgeoning evidence related to functional roles of signaling cascades in carcinogenesis and metastasis. Bufalin has been reported to regulate pleiotropically a myriad of signal transduction cascades in various cancers. Importantly, bufalin mechanistically regulated JAK/STAT, Wnt/β-Catenin, mTOR, TRAIL/TRAIL-R, EGFR, and c-MET pathways. Furthermore, bufalin-mediated modulation of non-coding RNAs in different cancers has also started to gain tremendous momentum. Similarly, bufalin-mediated targeting of tumor microenvironments and tumor macrophages is an area of exciting research and we have only started to scratch the surface of the complicated nature of molecular oncology. Cell culture studies and animal models provide proof-of-concept for the impetus role of bufalin in the inhibition of carcinogenesis and metastasis. Bufalin-related clinical studies are insufficient and interdisciplinary researchers require detailed analysis of the existing knowledge gaps.

Drug resistance mechanism of kinase inhibitors in the treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer, and it usually occurs following chronic liver disease. Although some progress has been made in the treatment of HCC, the prognosis of patients with advanced HCC is not optimistic, mainly because of the inevitable development of drug resistance. Therefore, multi-target kinase inhibitors for the treatment of HCC, such as sorafenib, lenvatinib, cabozantinib, and regorafenib, produce small clinical benefits for patients with HCC. It is necessary to study the mechanism of kinase inhibitor resistance and explore possible solutions to overcome this resistance to improve clinical benefits. In this study, we reviewed the mechanisms of resistance to multi-target kinase inhibitors in HCC and discussed strategies that can be used to improve treatment outcomes.

Bufalin for an innovative therapeutic approach against cancer

Bufalin is an endogenous cardiotonic steroid, first discovered in toad venom but also found in the plasma of healthy humans, with anti-tumour activities in different cancer types. The current review is focused on its mechanisms of action and highlights its very large spectrum of effects both in vitro and in vivo. All leads to the conclusion that bufalin mediates its effects by affecting all the hallmarks of cancer and seems restricted to cancer cells avoiding side effects. Bufalin decreases cancer cell proliferation by acting on the cell cycle and inducing different mechanisms of cell death including apoptosis, necroptosis, autophagy and senescence. Bufalin also moderates metastasis formation by blocking migration and invasion as well as angiogenesis and by inducing a phenotype switch towards differentiation and decreasing cancer cell stemness. Regarding its various mechanisms of action in cancer cells, bufalin blocks overactivated signalling pathways and modifies cell metabolism. Moreover, bufalin gained lately a huge interest in the field of drug resistance by both reversing various drug resistance mechanisms and affecting the immune microenvironment. Together, these data support bufalin as a quite promising new anti-cancer drug candidate.

Frontier progress of the combination of modern medicine and traditional Chinese medicine in the treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC, accounting for 90% of primary liver cancer) was the sixth most common cancer in the world and the third leading cause of cancer death in 2020. The number of new HCC patients in China accounted for nearly half of that in the world. HCC was of occult and complex onset, with poor prognosis. Clinically, at least 15% of patients with HCC had strong side effects of interventional therapy (IT) and have poor sensitivity to chemotherapy and targeted therapy. Traditional Chinese medicine (TCM), as a multi-target adjuvant therapy, had been shown to play an active anti-tumor role in many previous studies. This review systematically summarized the role of TCM combined with clinically commonly used drugs for the treatment of HCC (including mitomycin C, cyclophosphamide, doxorubicin, 5-fluorouracil, sorafenib, etc.) in the past basic research, and summarized the efficacy of TCM combined with surgery, IT and conventional therapy (CT) in clinical research. It was found that TCM, as an adjuvant treatment, played many roles in the treatment of HCC, including enhancing the tumor inhibition, reducing toxic and side effects, improving chemosensitivity and prolonging survival time of patients. This review summarized the advantages of integrated traditional Chinese and modern medicine in the treatment of HCC and provides a theoretical basis for clinical research.

Signal transducer and activator of transcription 3 cooperates with androgen receptor/cell cycle-related kinase signalling pathway in the progression of hepatitis B virus infection and gender differences

The study aimed to investigate the role of androgen receptor (AR)/cell cycle-related kinase (CCRK) signalling pathway in chronic hepatitis B virus (HBV) infection and gender differences, and the contribution of AR regulatory factor signal transducer and activator of transcription 3 (STAT3) in it. AR, CCRK, and phosphorylated STAT3 expressions in liver tissues of chronic HBV-infected patients and non-HBV controls were determined by western blot and compared between genders. The relationships of expression levels with serum HBV DNA levels, liver inflammation activity, and fibrosis score were analysed in chronic HBV-infected patients. The relationships between expression levels of three proteins were also analysed. HBV-infected patients had significantly higher expression levels of AR, CCRK, and p-STAT3^Tyr705 compared with controls (p < .01). The expression levels of AR, CCRK, and p-STAT3^Tyr705 in chronic HBV-infected patients with severe inflammation were significantly higher than those with mild inflammation (p < .05). Expression levels in patients with heavier fibrosis (stage F4) were higher than in those with less fibrosis (stages F0-3) (p < .01). No gender differences were observed in AR, CCRK, and p-STAT3^Tyr705 levels in non-HBV controls; higher levels were observed in HBV-infected males than in HBV-infected females (p < .05). AR, CCRK, and p-STAT3^Tyr705 levels in liver tissues positively correlated with each other (p < .0001) and with serum HBV DNA levels (p < .0001). In conclusion, in this study, we first found concordant over-expression of AR, CCRK, and STAT3 in liver tissues of chronic HBV-infected patients who have not yet developed HCC, significantly correlated with the severity of the disease and showed gender differences. STAT3 may be a potential therapeutic co-target for chronic HBV infection.

Research Progress in Pharmacological Activities and Applications of Cardiotonic Steroids

Cardiotonic steroids (CTS) are a group of compounds existing in animals and plants. CTS are commonly referred to cardiac glycosides (CGs) which are composed of sugar residues, unsaturated lactone rings and steroid cores. Their traditional mechanism of action is to inhibit sodium-potassium ATPase to strengthen the heart and regulate heart rate, so it is currently widely used in the treatment of cardiovascular diseases such as heart failure and tachyarrhythmia. It is worth noticing that recent studies have found an avalanche of inestimable values of CTS applications in many fields such as anti-tumor, anti-virus, neuroprotection, and immune regulation through multi-molecular mechanisms. Thus, the pharmacological activities and applications of CTS have extensive prospects, which would provide a direction for new drug research and development. Here, we review the potential applications of CTS in cardiovascular system and other systems. We also provide suggestions for new clinical practical strategies of CTS, for many diseases. Four main themes will be discussed, in relation to the impact of CTS, on 1) tumors, 2) viral infections, 3) nervous system diseases and 4) immune-inflammation-related diseases.

Bufalin stimulates antitumor immune response by driving tumor-infiltrating macrophage toward M1 phenotype in hepatocellular carcinoma

Background

Immunotherapy for hepatocellular carcinoma (HCC) exhibits limited clinical efficacy due to immunosuppressive tumor microenvironment (TME). Tumor-infiltrating macrophages (TIMs) account for the major component in the TME, and the dominance of M2 phenotype over M1 phenotype in the TIMs plays the pivotal role in sustaining the immunosuppressive character. We thus investigate the effect of bufalin on promoting TIMs polarization toward M1 phenotype to improve HCC immunotherapy.

Methods

The impact of bufalin on evoking antitumor immune response was evaluated in the immunocompetent mouse HCC model. The expression profiling of macrophage-associated genes, surface markers and cytokines on bufalin treatment in vitro and in vivo were detected using flow cytometry, immunofluorescence, western blot analysis, ELISA and RT-qPCR. Cell signaling involved in M1 macrophage polarization was identified via the analysis of gene sequencing, and bufalin-governed target was explored by immunoprecipitation, western blot analysis and gain-and-loss of antitumor immune response. The combination of bufalin and antiprogrammed cell death protein 1 (anti-PD-1) antibody was also assessed in orthotopic HCC mouse model.

Results

In this study, we showed that bufalin can function as an antitumor immune modulator that governs the polarization of TIMs from tumor-promoting M2 toward tumor-inhibitory M1, which induces HCC suppression through the activation of effector T cell immune response. Mechanistically, bufalin inhibits overexpression of p50 nuclear factor kappa B (NF-κB) factor, leading to the predominance of p65-p50 heterodimers over p50 homodimers in the nuclei. The accumulation of p65-p50 heterodimers activates NF-κB signaling, which is responsible for the production of immunostimulatory cytokines, thus resulting in the activation of antitumor T cell immune response. Moreover, bufalin enhances the antitumor activity of anti-PD-1 antibody, and the combination exerts synergistic effect on HCC suppression.

Conclusions

These data expound a novel antitumor mechanism of bufalin, and facilitate exploitation of a new potential macrophage-based HCC immunotherapeutic modality.

Current Perspective of Traditional Chinese Medicines and Active Ingredients in the Therapy of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the leading lethal tumors worldwide, and the treatment remains a great medical challenge. Surgery and chemotherapy are current standard curative methods for patients with HCC, but the prognosis is still dismal. Based on unique medical theories and rich practical experience, traditional Chinese medicine (TCM) has been broadly employed to effectively treat HCC for a long history. Recently, systematic clinical trials have been well designed to study the efficacy of TCMs in the treatment of HCC, and the underlying antitumor mechanisms were also deeply explored. Here, we reviewed the published clinical evaluation of some commonly used TCMs in the treatment of HCC, and the related anti-HCC mechanisms through in vitro and in vivo study, promoting the modernization of TCM study in oncology for achieving a substantial reduction of HCC burden in the future.

Synthesis and Evaluation of Novel Quinazolinone Derivatives as Potential Anti-HCC Agents

Hepatocellular carcinoma (HCC), a common malignancy worldwide, has a high mortality rate and limited effective therapeutic options. In this work, a series of quinazolinone compounds (6a-t and 7a-i) were synthesized as potential anti-HCC agents. Among them, compound 7b more potently inhibited HepG2, HUH7 and SK-Hep-1 cells proliferation than classical anti-HCC drug sorafenib, indicating its potential anti-HCC effect. Interestingly, 7b could dose-dependently decrease Cyclin D1 and CDK2 levels, and increase p21 protein expression, thus inducing HepG2 cells cycle arrest at G0/G1 phase. In addition, 7b also displayed potent apoptosis-induced effect on HepG2 cells by interfering Bad, Bax, Bcl-2 and Bcl-xl proteins expression. Notably, 7b could efficiently block the activity of PI3K pathway by dose-dependently reducing the phosphorylation of PI3K (Y607) and AKT (S473). Moreover, predicted ADME properties indicated that 7b possessed a good pharmacokinetic profile. Collectively, compound 7b might be a promising lead to the development of novel therapeutic agents towards HCC.