Cimigenoside functions as a novel γ-secretase inhibitor and inhibits the proliferation or metastasis of human breast cancer cells by γ-secretase/Notch axis

Traditional uses, phytochemistry, pharmacology, quality control and clinical studies of Cimicifugae Rhizoma: a comprehensive review

Cimicifugae Rhizoma, generally known as "Sheng Ma" in China, has great medicinal and dietary values. Cimicifugae Rhizoma is the dried rhizome of Cimicifuga foetida L., Cimicifuga dahurica (Turcz.) Maxim. and Cimicifuga heracleifolia Kom., which has been used to treat wind-heat headache, tooth pain, aphtha, sore throat, prolapse of anus and uterine prolapse in traditional Chinese medicine. This review systematically presents the traditional uses, phytochemistry, pharmacology, clinical studies, quality control and toxicity of Cimicifugae Rhizoma in order to propose scientific evidence for its rational utilization and product development. Herein, 348 compounds isolated or identified from the herb are summarized in this review, mainly including triterpenoid saponins, phenylpropanoids, chromones, alkaloids, terpenoids and flavonoids. The crude extracts and its constituents had various pharmacological properties such as anti-inflammatory, antitumor, antiviral, antioxidant, neuroprotective, anti-osteoporosis and relieving menopausal symptoms. The recent research progress of Cimicifugae Rhizoma in ethnopharmacology, phytochemistry and pharmacological effects demonstrates the effectiveness of its utilization and supplies valuable guidance for further research. This review will provide a basis for the future development and utilization of Cimicifugae Rhizoma.

Modulation of hypoxia-inducible factor-1 signaling pathways in cancer angiogenesis, invasion, and metastasis by natural compounds: a comprehensive and critical review

Tumor cells employ multiple signaling mediators to escape the hypoxic condition and trigger angiogenesis and metastasis. As a critical orchestrate of tumorigenic conditions, hypoxia-inducible factor-1 (HIF-1) is responsible for stimulating several target genes and dysregulated pathways in tumor invasion and migration. Therefore, targeting HIF-1 pathway and cross-talked mediators seems to be a novel strategy in cancer prevention and treatment. In recent decades, tremendous efforts have been made to develop multi-targeted therapies to modulate several dysregulated pathways in cancer angiogenesis, invasion, and metastasis. In this line, natural compounds have shown a bright future in combating angiogenic and metastatic conditions. Among the natural secondary metabolites, we have evaluated the critical potential of phenolic compounds, terpenes/terpenoids, alkaloids, sulfur compounds, marine- and microbe-derived agents in the attenuation of HIF-1, and interconnected pathways in fighting tumor-associated angiogenesis and invasion. This is the first comprehensive review on natural constituents as potential regulators of HIF-1 and interconnected pathways against cancer angiogenesis and metastasis. This review aims to reshape the previous strategies in cancer prevention and treatment.

Targeting the key players of phenotypic plasticity in cancer cells by phytochemicals

Plasticity of phenotypic traits refers to an organism's ability to change in response to environmental stimuli. As a result, the response may alter an organism's physiological state, morphology, behavior, and phenotype. Phenotypic plasticity in cancer cells describes the considerable ability of cancer cells to transform phenotypes through non-genetic molecular signaling activities that promote therapy evasion and tumor metastasis via amplifying cancer heterogeneity. As a result of metastable phenotypic state transitions, cancer cells can tolerate chemotherapy or develop transient adaptive resistance. Therefore, new findings have paved the road in identifying factors and agents that inhibit or suppress phenotypic plasticity. It has also investigated novel multitargeted agents that may promise new effective strategies in cancer treatment. Despite the efficiency of conventional chemotherapeutic agents, drug toxicity, development of resistance, and high-cost limit their use in cancer therapy. Recent research has shown that small molecules derived from natural sources are capable of suppressing cancer by focusing on the plasticity of phenotypic responses. This systematic, comprehensive, and critical review analyzes the current state of knowledge regarding the ability of phytocompounds to target phenotypic plasticity at both preclinical and clinical levels. Current challenges/pitfalls, limitations, and future perspectives are also discussed.

Inhibition of γ-secretase/Notch pathway as a potential therapy for reversing cancer drug resistance

The mechanism of tumor drug resistance is complex and may involve stem cell maintenance, epithelial-mesenchymal transition, the activation of survival signaling pathways, transporter protein expression, and tumor microenvironment remodeling, all of which are linked to γ-secretase/Notch signaling. Increasing evidence has shown that the activation of the γ-secretase/Notch pathway is a key driver of cancer progression and drug resistance development and that γ-secretase inhibitors (GSIs) may be the most promising agents for reversing chemotherapy resistance of tumors by targeting the γ-secretase/Notch pathway. Here, we systematically summarize the roles in supporting γ-secretase/Notch activation-associated transformation of cancer cells into cancer stem cells, promotion of the EMT process, PI3K/Akt, MEK/ERK and NF-κB activation, enhancement of ABC transporter protein expression, and TME alteration in mediating tumor drug resistance. Subsequently, we analyze the mechanism of GSIs targeting the γ-secretase/Notch pathway to reverse tumor drug resistance and propose the outstanding advantages of GSIs in treating breast cancer drug resistance over other tumors. Finally, we emphasize that the development of GSIs for reversing tumor drug resistance is promising.

NIO-1, A Novel Inhibitor of OCT1, Enhances the Antitumor Action of Radiofrequency Ablation against Hepatocellular Carcinoma

BACKGROUND

Radiofrequency ablation (RFA) is an important treatment strategy for patients with advanced hepatocellular carcinoma (HCC). However, its therapeutic effect is unsatisfactory and recurrence often occurs after RFA treatment. The octamer-binding transcription factor OCT1 is a novel tumour-promoting factor and an ideal target for HCC therapy.

OBJECTIVE

This study aimed to expand the understanding of HCC regulation by OCT1.

METHODS

The expression levels of the target genes were examined using qPCR. The inhibitory effects of a novel inhibitor of OCT1 (NIO-1) on HCC cells and OCT1 activation were examined using Chromatin immunoprecipitation or cell survival assays. RFA was performed in a subcutaneous tumour model of nude mice.

RESULTS

Patients with high OCT1 expression in the tumour tissue had a poor prognosis after RFA treatment (n = 81). The NIO-1 showed antitumor activity against HCC cells and downregulated the expression of the downstream genes of OCT1 in HCC cells, including those associated with cell proliferation (matrix metalloproteinase-3) and epithelial-mesenchymal transition-related factors (Snail, Twist, N-cadherin, and vimentin). In a subcutaneous murine model of HCC, NIO-1 enhanced the effect of RFA treatment on HCC tissues (n = 8 for NIO-1 and n = 10 for NIO-1 + RFA).

CONCLUSION

This study demonstrated the clinical importance of OCT1 expression in HCC for the first time. Our findings also revealed that NIO-1 aids RFA therapy by targeting OCT1.

Regulation of the Notch signaling pathway by natural products for cancer therapy

The Notch signaling pathway is an evolutionarily conserved pathway that modulates normal biological processes involved in cellular differentiation, apoptosis, and stem cell self-renewal in a context-dependent fashion. Attributed to its pleiotropic physiological roles, both overexpression and silencing of the pathway are associated with the emergence, progression, and poorer prognosis in various types of cancer. To decrease disease incidence and promote survival, targeting Notch may have chemopreventive and anti-cancer effects. Natural products with profound historical origins have distinguished themselves from other therapies due to their easy access, high biological compatibility, low toxicity, and reliable effects at specific physiological sites in vivo. This review describes the Notch signaling pathway, particularly its normal activation process, and some main illnesses related to Notch signaling pathway dysregulation. Emphasis is placed on the effects and mechanisms of natural products targeting the Notch signaling pathway in diverse cancer types, including curcumin, ellagic acid (EA), resveratrol, genistein, epigallocatechin-3-gallate (EGCG), quercetin, and xanthohumol and so on. Existing evidence indicates that natural products are feasible solution to fight against cancer by targeting Notch signaling, either alone or in combination with current therapeutic agents.

Novel structured ADAM17 small-molecule inhibitor represses ADAM17/Notch pathway activation and the NSCLC cells' resistance to anti-tumour drugs

Background and aims: The outcomes of current treatment for non-small cell lung cancer (NSCLC) are unsatisfactory and development of new and more efficacious therapeutic strategies are required. The Notch pathway, which is necessary for cell survival to avert apoptosis, induces the resistance of cancer cells to antitumour drugs. Notch pathway activation is controlled by the cleavage of Notch proteins/receptors mediated by A disintegrin and metalloproteinase 17 (ADAM17); therefore, ADAM17 is a reliable intervention target for anti-tumour therapy to overcome the drug resistance of cancer cells. This work aims to develop and elucidate the activation of Compound 2b, a novel-structured small-molecule inhibitor of ADAM17, which was designed and developed and its therapeutic efficacy in NSCLC was assessed via multi-assays. Methods and results: A lead compound for a potential inhibitor of ADAM17 was explored via pharmacophore modelling, molecular docking, and biochemical screening. It was augmented by substituting two important chemical groups [R1 and R2 of the quinoxaline-2,3-diamine (its chemical skeleton)]; subsequently, serial homologs of the lead compound were used to obtain anoptimized compound (2b) with high inhibitory activity compared with leading compound against ADAM17 to inhibit the cleavage of Notch proteins and the accumulation of the Notch intracellular domain in the nuclei of NSCLC cells. The inhibitory activity of compound 2b was demonstrated by quantitative polymerase chain reaction and Western blotting. The specificity of compound 2b on ADAM17 was confirmed via point-mutation. Compound 2b enhanced the activation of antitumor drugs on NSCLC cells, in cell lines and nude mice models, by targeting the ADAM17/Notch pathway. Conclusion: Compound 2b may be a promising strategy for NSCLC treatment.

Review deciphering potent therapeutic approaches targeting Notch signaling pathway in breast cancer

In the current period of drug development, natural products have provided an unrivaled supply of anticancer medications. By modifying the cancer microenvironment and various signaling pathways, natural products and their derivatives and analogs play a significant role in cancer treatment. These substances are effective against several signaling pathways, particularly the cell death pathways (apoptosis and autophagy) and embryonic developmental pathways (Notch, Wnt, and Hedgehog pathways). Natural products have a long history, but more research is needed to understand their current function in the research and development of cancer treatments and the potential for natural products to serve as a significant source of therapeutic agents in the future. Several target-specific anticancer medications failed to treat cancer, necessitating research into natural compounds with multiple target properties. To help develop a better treatment plan for managing breast cancer, this review has outlined the anticancerous potential of several therapeutic approaches targeting the notch signaling system in breast tumors.

Pancreatic cancer stemness: dynamic status in malignant progression

Pancreatic cancer (PC) is one of the most aggressive malignancies worldwide. Increasing evidence suggests that the capacity for self-renewal, proliferation, and differentiation of pancreatic cancer stem cells (PCSCs) contribute to major challenges with current PC therapies, causing metastasis and therapeutic resistance, leading to recurrence and death in patients. The concept that PCSCs are characterized by their high plasticity and self-renewal capacities is central to this review. We focused specifically on the regulation of PCSCs, such as stemness-related signaling pathways, stimuli in tumor cells and the tumor microenvironment (TME), as well as the development of innovative stemness-targeted therapies. Understanding the biological behavior of PCSCs with plasticity and the molecular mechanisms regulating PC stemness will help to identify new treatment strategies to treat this horrible disease.

Ginsenoside Rb1 for overcoming cisplatin-insensitivity of A549/DDP cells in vitro and vivo through the dual-inhibition on two efflux pumps of ABCB1 and PTCH1

BACKGROUND

The multi-drug resistance is an inherent weakness in the chemotherapeutics of non-small cell lung cancer occurring frequently all over the world. Clinically, ginseng and Chinese medicinal prescriptions including ginseng usually used as anti-tumor adjuncts due to its characteristic of qi-invigorating, which could improve the curative effect of chemotherapy drugs and reduce their toxic side effects. Triterpenoid saponins are the crucial active ingredients in Panax ginseng, and Ginsenoside Rb₁ is of the highest quantities. However, the research on the tumor drug-resistance reversal effect and mechanism of ginsenoside Rb₁ is still not clear.

PURPOSE

This study aimed to systematically estimate the reversal activity of Ginsenoside Rb₁ on cisplatin-insensitivity of A549/DDP cells and to reveal its prospective molecular mechanism.

METHODS

MTT assay were conducted to evaluate the reversal activity on cisplatin-insensitivity of A549/DDP cells of Ginsenoside Rb₁in vitro, and the behavior was also studied by establishing a subcutaneous transplanted tumor model of A549/DDP in BALB/c-nu mice. In addition, P-gp ATPase activity assay, cisplatin accumulation assay, Annexin V-FITC apoptosis assay, real-time qPCR analysis and western blotting analysis were used to clarify the potential mechanism.

RESULTS

Ginsenoside Rb₁ could effectively reverse the cisplatin-resistance of A549/DDP in vitro and vivo. And after the co-treatment of Ginsenoside Rb₁ plus cisplatin, the accumulation of cisplatin increased in A549/DDP cells, which was accompanied with the down-regulation of the mRNA and protein expression levels of ABCB1, SHH, PTCH1 and GLI2. Besides, the apoptosis-inducing ability of cisplatin improved by the relative regulation on the protein expression level of Bax and Bcl-2. Far more importantly, the changes of CYP3A4 mRNA and protein levels were not significant.

CONCLUSION

Ginsenoside Rb₁ could increase the concentration of intracellular cisplatin and improve the insensitivity for cisplatin on A549/DDP cells. Even better, there was perhaps no unpredictable CYP3A4-mediated pharmacokinetic interactions after the combination of Ginsenoside Rb₁ plus cisplatin. Ginsenoside Rb₁ was a probable reversal agent for the cisplatin-insensitivity of A549/DDP cells, with a bifunction of inhibiting the efflux of two drug pumps (P-gp and PTCH1) by targeting ABCB1 and Hedgehog (Hh) pathway. In general, this research laid the groundwork for the development of a new reversal agent for the cisplatin-insensitivity of NSCLC.

TPX2 enhances the transcription factor activation of PXR and enhances the resistance of hepatocellular carcinoma cells to antitumor drugs

The pregnane X receptor (PXR) is an important regulator of hepatocellular carcinoma cellular resistance to antitumor drugs. Activation of PXR was modulated by the co-regulators. The target protein for the Xenopus plus end-directed kinesin-like protein (Xklp2) known as TPX2 that was previously considered as a tubulin regulator, also functions as the regulator of some transcription factors and pro-oncogenes in human malignances. However, the actions of TPX2 on PXR and HCC cells are still unclear. In the present study, our results demonstrate that the high expression of endogenous mRNA level of TPX2 not only correlated with the poor prognosis of advanced HCC patients who received sorafenib treatment but also with expression of PXR's downstream genes, cyp3a4 and/or mdr-1. Results from luciferase and real-time polymerase chain reaction (qPCR) showed that TPX2 leads to enhancement of the transcription factor activation of PXR. Protein-protein interactions between PXR and TPX2 were identified using co-immunoprecipitation. Mechanically, overexpression of TPX2 led to enhancement of PXR recruitment to its downstream gene cyp3a4's promoter region (the PXRE region) or enhancer region (the XREM region). Treatment of HCC cells with paclitaxel, a microtubule promoter, led to enhancement of the effects of TPX2, whereas vincristine, a microtubule depolymerizing agent caused a decrease in TPX2-associated effects. TPX2 was found to cause acceleration of the metabolism or clearance of sorafenib, a typical tyrosine kinase inhibitor (TKI) in HCC cells and in turn led to the resistance to sorafenib by HCC cells. By establishing novel actions of TXP2 on PXR in HCC cells, the results indicate that TPX2 could be considered a promising therapeutic target to enhance HCC cells sensitivity to antitumor drugs.

The Notch Signaling Pathway Contributes to Angiogenesis and Tumor Immunity in Breast Cancer

Breast cancer in women is the first leading tumor in terms of incidence worldwide. Some subtypes of BC lack distinct molecular targets and exhibit therapeutic resistance; these patients have a poor prognosis. Thus, the search for new molecular targets is an ongoing challenge for BC therapy. The Notch signaling pathway is found in both vertebrates and invertebrates, and it is a highly conserved in the evolution of the species, controlling cellular fates such as death, proliferation, and differentiation. Numerous studies have shown that improper activation of Notch signaling may lead to excessive cell proliferation and cancer, with tumor-promoting and tumor-suppressive effects in various carcinomas. Thus, inhibitors of Notch signaling are actively being investigated for the treatment of various tumors. The role of Notch signaling in BC has been widely studied in recent years. There is a growing body of evidence suggesting that Notch signaling has a pro-oncogenic role in BC, and the tumor-promoting effect is largely a result of the diverse nature of tumor immunity. Immunological abnormality is also a factor involved in the pathogenesis of BC, suggesting that Notch signaling could be a target for BC immunotherapies. Furthermore, angiogenesis is essential for BC growth and metastasis, and the Notch signaling pathway has been implicated in angiogenesis, so studying the role of Notch signaling in BC angiogenesis will provide new prospects for the treatment of BC. We summarize the potential roles of the current Notch signaling pathway and its inhibitors in BC angiogenesis and the immune response in this review and describe the pharmacological targets of Notch signaling in BC, which may serve as a theoretical foundation for future research into exploring this pathway for novel BC therapies.

MTBP enhances the activation of transcription factor ETS-1 and promotes the proliferation of hepatocellular carcinoma cells

Increasing evidence indicates that the oncoprotein murine double minute (MDM2) binding protein (MTBP) can be considered a pro-oncogene of human malignancies; however, its function and mechanisms in hepatocellular carcinoma (HCC) are still not clear. In the present work, our results demonstrate that MTBP could function as a co-activator of transcription factor E26 transformation-specific sequence (ETS-1), which plays an important role in HCC cell proliferation and/or metastasis and promotes proliferation of HCC cells. Using luciferase and real-time polymerase chain reaction (qPCR) assays, MTBP was found to enhance the transcription factor activation of ETS-1. The results from chromatin co-immunoprecipitation showed that MTBP enhanced the recruitment of ETS-1 to its downstream gene’s (mmp1’s) promoter region with ETS-1 binding sites. In cellular and nude mice models, overexpression of MTBP was shown to promote the proliferation of MHCC97-L cells with low endogenous MTBP levels, whereas the knockdown of MTBP led to inhibition of the proliferation of MHCC97-H cells that possessed high endogenous levels of MTBP. The effect of MTBP on ETS-1 was confirmed in the clinical specimens; the expression of MTBP was positively correlated with the downstream genes of ETS-1, mmp3, mmp9, and uPA. Therefore, by establishing the role of MTBP as a novel co-activator of ETS-1, this work expands our knowledge of MTBP or ETS-1 and helps to provide new ideas concerning HCC-related research.

DHW-208, A Novel Phosphatidylinositol 3-Kinase (PI3K) Inhibitor, Has Anti-Hepatocellular Carcinoma Activity Through Promoting Apoptosis and Inhibiting Angiogenesis

Hepatocellular carcinoma (HCC) is one of the most common tumors worldwide with high prevalence and lethality. Due to insidious onset and lack of early symptoms, most HCC patients are diagnosed at advanced stages without adequate methods but systemic therapies. PI3K/AKT/mTOR signaling pathway plays a crucial role in the progression and development of HCC. Aberrant activation of PI3K/AKT/mTOR pathway is involved in diverse biological processes, including cell proliferation, apoptosis, migration, invasion and angiogenesis. Therefore, the development of PI3K-targeted inhibitors is of great significance for the treatment of HCC. DHW-208 is a novel 4-aminoquinazoline derivative pan-PI3K inhibitor. This study aimed to assess the therapeutic efficacy of DHW-208 in HCC and investigate its underlying mechanism. DHW-208 could inhibit the proliferation, migration, invasion and angiogenesis of HCC through the PI3K/AKT/mTOR signaling pathway in vitro. Consistent with the in vitro results, in vivo studies demonstrated that DHW-208 elicits an antitumor effect by inhibiting the PI3K/AKT/mTOR-signaling pathway with a high degree of safety in HCC. Therefore, DHW-208 is a candidate compound to be developed as a small molecule PI3K inhibitor for the treatment of HCC, and our study provides a certain theoretical basis for the treatment of HCC and the development of PI3K inhibitors.

A Single Nucleotide Mixture Enhances the Antitumor Activity of Molecular-Targeted Drugs Against Hepatocellular Carcinoma

New strategies for molecular-targeted drug therapy for advanced hepatocellular carcinoma (HCC) ignore the contribution of the nutritional status of patients and nutritional support to improve physical status and immunity. We aimed to elucidate the role of a single nucleotide mixture (SNM) in the anti-tumor therapy of HCC, and to explore the importance of a SNM as adjuvant therapy for HCC. Compared with a lipid emulsion (commonly used nutritional supplement for HCC patients), the SNM could not induce metabolic abnormalities in HCC cells (Warburg effect), and did not affect expression of metabolic abnormality-related factors in HCC cells. The SNM could also attenuate the lymphocyte injury induced by antitumor drugs in vitro and in vivo, and promote the recruitment and survival of lymphocytes in HCC tissues. Using HCC models in SCID (server combined immune-deficiency) mice or BalB/c mice, the SNM had anti-tumor activity, and could significantly upregulate the antitumor activity of molecular-targeted drugs (tyrosine-kinase inhibitors [TKI] and immune-checkpoint inhibitors [ICI]) against HCC. We employed research models in vivo and in vitro to reveal the anti-tumor activity of the SNM on HCC. Our findings expand understanding of the SNM and contribute to HCC (especially nutritional support) therapy.

Knockdown of TANK-Binding Kinase 1 Enhances the Sensitivity of Hepatocellular Carcinoma Cells to Molecular-Targeted Drugs

The protein kinase, TANK-binding kinase 1 (TBK1), not only regulates various biological processes but also functions as an important regulator of human oncogenesis. However, the detailed function and molecular mechanisms of TBK1 in hepatocellular carcinoma (HCC), especially the resistance of HCC cells to molecular-targeted drugs, are almost unknown. In the present work, the role of TBK1 in regulating the sensitivity of HCC cells to molecular-targeted drugs was measured by multiple assays. The high expression of TBK1 was identified in HCC clinical specimens compared with paired non-tumor tissues. The high level of TBK1 in advanced HCC was associated with a poor prognosis in patients with advanced HCC who received the molecular-targeted drug, sorafenib, compared to patients with advanced HCC patients and a low level of TBK1. Overexpression of TBK1 in HCC cells induced their resistance to molecular-targeted drugs, whereas knockdown of TBK1 enhanced the cells’ sensitivity to molecular-targeted dugs. Regarding the mechanism, although overexpression of TBK1 enhanced expression levels of drug-resistance and pro-survival-/anti-apoptosis-related factors, knockdown of TBK1 repressed the expression of these factors in HCC cells. Therefore, TBK1 is a promising therapeutic target for HCC treatment and knockdown of TBK1 enhanced sensitivity of HCC cells to molecular-targeted drugs.

A Novel Small-Molecule Inhibitor of SREBP-1 Based on Natural Product Monomers Upregulates the Sensitivity of Lung Squamous Cell Carcinoma Cells to Antitumor Drugs

The transcription factor, sterol regulatory element binding protein 1 (SREBP-1), plays important roles in modulating the proliferation, metastasis, or resistance to antitumor agents by promoting cellular lipid metabolism and related cellular glucose-uptake/Warburg Effect. However, the underlying mechanism of SREBP-1 regulating the proliferation or drug-resistance in lung squamous cell carcinoma (LUSC) and the therapeutic strategies targeted to SREBP-1 in LUSC remain unclear. In this study, SREBP-1 was highly expressed in LUSC tissues, compared with the paired non-tumor tissues (the para-tumor tissues). A novel small-molecule inhibitor of SREBP-1, MSI-1 (Ma’s inhibitor of SREBP-1), based on natural product monomers, was identified by screening the database of natural products. Treatment with MSI-1 suppressed the activation of SREBP-1-related pathways and the Warburg effect of LUSC cells, as indicated by decreased glucose uptake or glycolysis. Moreover, treatment of MSI-1 enhanced the sensitivity of LUSC cells to antitumor agents. The specificity of MSI-1 on SREBP-1 was confirmed by molecular docking and point-mutation of SPEBP-1. Therefore, MSI-1 improved our understanding of SREBP-1 and provided additional options for the treatment of LUSC.

A Review of Twenty Years of Research on the Regulation of Signaling Pathways by Natural Products in Breast Cancer

Breast cancer (BC) is the second leading cause of death among women, and it has become a global health issue due to the increasing number of cases. Different treatment options, including radiotherapy, surgery, chemotherapy and anti-estrogen therapy, aromatase inhibitors, anti-angiogenesis drugs, and anthracyclines, are available for BC treatment. However, due to its high occurrence and disease progression, effective therapeutic options for metastatic BC are still lacking. Considering this scenario, there is an urgent need for an effective therapeutic strategy to meet the current challenges of BC. Natural products have been screened as anticancer agents as they are cost-effective, possess low toxicity and fewer side effects, and are considered alternative therapeutic options for BC therapy. Natural products showed anticancer activities against BC through the inhibition of angiogenesis, cell migrations, proliferations, and tumor growth; cell cycle arrest by inducing apoptosis and cell death, the downstream regulation of signaling pathways (such as Notch, NF-κB, PI3K/Akt/mTOR, MAPK/ERK, and NFAT-MDM2), and the regulation of EMT processes. Natural products also acted synergistically to overcome the drug resistance issue, thus improving their efficacy as an emerging therapeutic option for BC therapy. This review focused on the emerging roles of novel natural products and derived bioactive compounds as therapeutic agents against BC. The present review also discussed the mechanism of action through signaling pathways and the synergistic approach of natural compounds to improve their efficacy. We discussed the recent in vivo and in vitro studies for exploring the overexpression of oncogenes in the case of BC and the current status of newly discovered natural products in clinical investigations.

A Novel Small Molecular Inhibitor of DNMT1 Enhances the Antitumor Effect of Radiofrequency Ablation in Lung Squamous Cell Carcinoma Cells

Radiofrequency ablation (RFA) is a relatively new and effective therapeutic strategy for treating lung squamous cell carcinomas (LSCCs). However, RFA is rarely used in the clinic for LSCC which still suffers from a lack of effective comprehensive treatment strategies. In the present work, we investigate iDNMT, a novel small molecular inhibitor of DNMT1 with a unique structure. In clinical LSCC specimens, endogenous DNMT1 was positively associated with methylation rates of miR-27-3p's promoter. Moreover, endogenous DNMT1 was negatively correlated with miR-27-3p expression which targets PSEN-1, the catalytic subunit of γ-secretase, which mediates the cleavage and activation of the Notch pathway. We found that DNMT1 increased activation of the Notch pathway in clinical LSCC samples while downregulating miR-27-3p expression and hypermethylation of miR-27-3p's promoter. In addition of inhibiting activation of the Notch pathway by repressing methylation of the miR-27-3p promoter, treatment of LSCC cells with iDNMT1 also enhanced the sensitivity of LSCC tumor tissues to RFA treatment. These data suggest that iDNMT-induced inhibition of DNMT-1 enhances miR-27-3p expression in LSCC to inhibit activation of the Notch pathway. Furthermore, the combination of iDNMT and RFA may be a promising therapeutic strategy for LSCC.

Inhibition of SREBP-1 Activation by a Novel Small-Molecule Inhibitor Enhances the Sensitivity of Hepatocellular Carcinoma Tissue to Radiofrequency Ablation

Radiofrequency ablation (RFA) is an important strategy for treatment of advanced hepatocellular carcinoma (HCC). However, the prognostic indicators of RFA therapy are not known, and there are few strategies for RFA sensitization. The transcription factor sterol regulatory element binding protein 1 (SREBP)-1 regulates fatty-acid synthesis but also promotes the proliferation or metastasis of HCC cells. Here, the clinical importance of SREBP-1 and potential application of knockdown of SREBP-1 expression in RFA of advanced HCC was elucidated. In patients with advanced HCC receiving RFA, a high level of endogenous SREBP-1 expression correlated to poor survival. Inhibition of SREBP-1 activation using a novel small-molecule inhibitor, SI-1, not only inhibited the aerobic glycolysis of HCC cells, it also enhanced the antitumor effects of RFA on xenograft tumors. Overall, our results: (i) revealed the correlation between SREBP-1 and HCC severity; (ii) indicated that inhibition of SREBP-1 activation could be a promising approach for treatment of advanced HCC.

A Novel Microcrystalline BAY-876 Formulation Achieves Long-Acting Antitumor Activity Against Aerobic Glycolysis and Proliferation of Hepatocellular Carcinoma

BAY-876 is an effective antagonist of the Glucose transporter type 1 (GLUT1) receptor, a mediator of aerobic glycolysis, a biological process considered a hallmark of hepatocellular carcinoma (HCC) together with cell proliferation, drug-resistance, and metastasis. However, the clinical application of BAY-876 has faced many challenges. In the presence study, we describe the formulation of a novel microcrystalline BAY-876 formulation. A series of HCC tumor models were established to determine not only the sustained release of microcrystalline BAY-876, but also its long-acting antitumor activity. The clinical role of BAY-876 was confirmed by the increased expression of GLUT1, which was associated with the worse prognosis among advanced HCC patients. A single dose of injection of microcrystalline BAY-876 directly in the HCC tissue achieved sustained localized levels of Bay-876. Moreover, the single injection of microcrystalline BAY-876 in HCC tissues not only inhibited glucose uptake and prolonged proliferation of HCC cells, but also inhibited the expression of epithelial-mesenchymal transition (EMT)-related factors. Thus, the microcrystalline BAY-876 described in this study can directly achieve promising localized effects, given its limited diffusion to other tissues, thereby reducing the occurrence of potential side effects, and providing an additional option for advanced HCC treatment.

Knockdown of FBI-1 Inhibits the Warburg Effect and Enhances the Sensitivity of Hepatocellular Carcinoma Cells to Molecular Targeted Agents via miR-3692/HIF-1α

The transcription suppressor factor FBI-1 (the factor that binds to inducer of short transcripts-1) is an important regulator of hepatocellular carcinoma (HCC). In this work, the results showed that FBI-1 promoted the Warburg effect and enhances the resistance of hepatocellular carcinoma cells to molecular targeted agents. Knockdown of FBI-1 via its small-interfering RNA (siRNA) inhibited the ATP level, lactate productions, glucose uptake or lactate dehydrogenase (LDH) activation of HCC cells. Transfection of siFBI-1 also decreased the expression of the Warburg-effect-related factors: hypoxia-inducible factor-1 alpha (HIF-1α), lactate dehydrogenase A (LDHA), or GLUT1, and the epithelial-mesenchymal transition-related factors, Vimentin or N-cadherin. The positive correlation between the expression of FBI-1 with HIF-1α, LDHA, or GLUT1 was confirmed in HCC tissues. Mechanistically, the miR-30c repressed the expression of HIF-1α by binding to the 3'-untranslated region (3'-UTR) of HIF-1α in a sequence-specific manner, and FBI-1 enhanced the expression of HIF-1α and HIF-1α pathway's activation by repressing the expression of miR. By modulating the miR-30c/HIF-1α, FBI-1 promoted the Warburg effect or the epithelial-mesenchymal transition of HCC cells and promoted the resistance of HCC cells to molecular targeted agents.

CK-3, A Novel Methsulfonyl Pyridine Derivative, Suppresses Hepatocellular Carcinoma Proliferation and Invasion by Blocking the PI3K/AKT/mTOR and MAPK/ERK Pathways

Hepatocellular carcinoma (HCC) is an aggressive tumor with a poor prognosis that highly expresses phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (ERK). The PI3K/AKT/mTOR and MAPK/ERK signaling pathways play a crucial role in HCC tumor formation, cell cycle, apoptosis and survival. However, no effective targeted therapies against these pathways is available, mainly due to the extensive and complex negative feedback loops between them. Here we used CK-3, a dual blocker of the PI3K/AKT/mTOR and MAPK/ERK pathways, against HCC cell lines to verify its anti-tumor activity in vitro. CK-3 exhibited cytotoxic activity against HCC, as demonstrated with MTT and colony formation assays. The anti-metastatic potential of CK-3 was demonstrated with wound healing and cell invasion assays. The ability of CK-3 to block both the PI3K/AKT/mTOR and MAPK/ERK pathways was also confirmed. CK-3 induced the apoptosis of Hep3B cells, while Bel7402 cells died via mitotic catastrophe (MC). Oral administration of CK-3 also inhibited the subcutaneous growth of BEL7402 cells in nude mice. Simultaneous PI3K/AKT/mTOR and MAPK/ERK pathway inhibition with CK-3 may be superior to single pathway monotherapies by inhibiting their feedback-regulation, and represents a potential treatment for HCC.

Hsa-miR-4277 Decelerates the Metabolism or Clearance of Sorafenib in HCC Cells and Enhances the Sensitivity of HCC Cells to Sorafenib by Targeting cyp3a4

Increasing evidence has shown that the metabolism and clearance of molecular targeted agents, such as sorafenib, plays an important role in mediating the resistance of HCC cells to these agents. Metabolism of sorafenib is performed by oxidative metabolism, which is initially mediated by CYP3A4. Thus, targeting CYP3A4 is a promising approach to enhance the sensitivity of HCC cells to chemotherapeutic agents. In the present work, we examined the association between CYP3A4 and the prognosis of HCC patients receiving sorafenib. Using the online tool miRDB, we predicted that has-microRNA-4277 (miR-4277), an online miRNA targets the 3’UTR of the transcript of cyp3a4. Furthermore, overexpression of miR-4277 in HCC cells repressed the expression of CYP3A4 and reduced the elimination of sorafenib in HCC cells. Moreover, miR-4277 enhanced the sensitivity of HCC cells to sorafenib in vitro and in vivo. Therefore, our results not only expand our understanding of CYP3A4 regulation in HCC, but also provide evidence for the use of miR-4277 as a potential therapeutic in advanced HCC.

MDM2 Binding Protein Induces the Resistance of Hepatocellular Carcinoma Cells to Molecular Targeting Agents via Enhancing the Transcription Factor Activity of the Pregnane X Receptor

The MDM2 binding protein (MTBP) has been considered an important regulator of human malignancies. In this study, we demonstrate that the high level of MTBP’s endogenous expression is correlated with poor prognosis of advanced hepatocellular carcinoma (HCC) patients who received sorafenib. MTBP interacted with the Pregnane X receptor (PXR) and enhanced the transcription factor activity of PXR. Moreover, MTBP enhanced the accumulation of PXR in HCC cells’ nuclear and the recruitment of PXR to its downstream gene’s (cyp3a4’s) promoter region. Mechanically, the knockdown of MTBP in MHCC97-H cells with high levels of MTBP decelerated the clearance or metabolism of sorafenib in HCC cells and led to the resistance of HCC cells to sorafenib. Whereas overexpression of MTBP in in MHCC97-L cells with low levels of MTBP showed the opposite trend. By establishing the interaction between MTBP and PXR, our results indicate that MTBP could function as a co-activator of PXR and could be a promising therapeutic target to enhance the sensitivity of HCC cells to molecular targeting agents.