Silencing c-Myc Enhances the Antitumor Activity of Bufalin by Suppressing the HIF-1α/SDF-1/CXCR4 Pathway in Pancreatic Cancer Cells

Combinational Antitumor Strategies Based on the Active Ingredients of Toad Skin and Toad Venom

A multidrug combination strategy is an important mean to improve the treatment of cancer and is the mainstream scheme of clinical cancer treatment. The active ingredients of traditional Chinese medicine, represented by toad skin and toad venom, have the advantages of high efficiency, low toxicity, wide action and multiple targets and have become ideal targets in combined treatment strategies for tumors in recent years. Toad skin and toad venom are traditional Chinese animal medicines derived from Bufo bufo gargarizans Cantor or Bufo melanostictus Schneider that have shown excellent therapeutic effects on the treatment of various cancers and cancer pain as adjuvant antitumor drugs in clinical practice. The involved mechanisms include inducing apoptosis, arresting the cell cycle, inhibiting cell proliferation, migration and invasion, inhibiting tumor angiogenesis, reversing the multidrug resistance of tumor cells, and regulating multiple signaling pathways and targets. Moreover, a multidrug combination strategy based on a nanodelivery system can realize the precise loading of the active ingredients of toad skin or toad venom and other antitumor drugs and carry drugs to overcome physiological and pathological barriers, complete efficient enrichment in tumor tissues, and achieve targeted delivery to tumor cells and the controlled release of drugs, thus enhancing antitumor efficacy and reducing toxicity and side effects. This article reviewed the clinical efficacy and safety of the combination of toad skin and toad venom with chemotherapeutic drugs, targeted drugs, analgesics and other drugs; evaluated the effects and mechanisms of the combination of toad skin and toad venom with chemotherapy, targeted therapy, radiotherapy or hyperthermia, traditional Chinese medicine, signaling pathway inhibitors and other therapies in cell and animal models; and summarized the codelivery strategies for the active ingredients of toad skin and toad venom with chemotherapeutic drugs, small-molecule targeted drugs, monoclonal antibodies, active ingredients of traditional Chinese medicine, and photodynamic and photothermal therapeutic drugs to provide a basis for the rational drug use of toad skin and toad venom in the clinic and the development of novel drug delivery systems.

Chemical Composition, Pharmacological Effects and Clinical Applications of Cinobufacini

Chinese medicine cinobufacini is an extract from the dried skin of Bufo bufo gargarizans Cantor, with active ingredients of bufadienolides and indole alkaloids. With further research and clinical applications, it is found that cinobufacini alone or in combination with other therapeutic methods can play an anti-tumor role by controlling proliferation of tumor cells, promoting apoptosis, inhibiting formation of tumor neovascularization, reversing multidrug resistance, and regulating immune response; it also has the functions of relieving cancer pain and regulating immune function. In this paper, the chemical composition, pharmacological effects, clinical applications, and adverse reactions of cinobufacini are summarized. However, the extraction of monomer components of cinobufacini, the relationship between different mechanisms, and the causes of adverse reactions need to be further studied. Also, high-quality clinical studies should be conducted.

The Warburg effect drives cachectic states in patients with pancreatobiliary adenocarcinoma

We have studied whether the Warburg effect (uncontrolled glycolysis) in pancreatobiliary adenocarcinoma triggers cachexia in the patient. After 74 pancreatobiliary adenocarcinomas were removed by surgery, their glucose transporter-1 and four glycolytic enzymes were quantified using Western blotting. Based on the resulting data, the adenocarcinomas were equally divided into a group of low glycolysis (LG) and a group of high glycolysis (HG). Energy homeostasis was assessed in these cancer patients and in 74 non-cancer controls, using serum albumin and C-reactive protein and morphometrical analysis of abdominal skeletal muscle and fat on computed tomography scans. Some removed adenocarcinomas were transplanted in nude mice to see their impacts on host energy homeostasis. Separately, nude mice carrying tumor grafts of MiaPaCa-2 pancreatic adenocarcinoma cells were treated with the glycolytic inhibitor 3-bromopyruvate and with emodin that inhibited glycolysis by decreasing hypoxia-inducible factor-1α. Adenocarcinomas in both group LG and group HG impaired energy homeostasis in the cancer patients, compared to the non-cancer reference. The impaired energy homeostasis induced by the adenocarcinomas in group HG was more pronounced than that by the adenocarcinomas in group LG. When original adenocarcinomas were grown in nude mice, their glycolytic abilities determined the levels of hepatic gluconeogenesis, skeletal muscle proteolysis, adipose-tissue lipolysis, and weight loss in the mice. When MiaPaCa-2 cells were grown as tumors in nude mice, 3-bromopyruvate and emodin decreased tumor-induced glycolysis and cachexia, with the best effects being seen when the drugs were administered in combination. In conclusion, the Warburg effect in pancreatobiliary adenocarcinoma triggers cancer cachexia.

Advances in the treatment of pancreatic cancer with traditional Chinese medicine

Pancreatic cancer is a common malignancy of the digestive system. With a high degree of malignancy and poor prognosis, it is called the "king of cancers." Currently, Western medicine treats pancreatic cancer mainly by surgical resection, radiotherapy, and chemotherapy. However, the curative effect is not satisfactory. The application of Traditional Chinese Medicine (TCM) in the treatment of pancreatic cancer has many advantages and is becoming an important facet of comprehensive clinical treatment. In this paper, we review current therapeutic approaches for pancreatic cancer. We also review the protective effects shown by TCM in different models and discuss the potential molecular mechanisms of these.

Molecular and metabolic mechanisms of bufalin against lung adenocarcinoma: New and comprehensive evidences from network pharmacology, metabolomics and molecular biology experiment

BACKGROUND

This study aims to evaluate the efficacy and therapeutic mechanism of bufalin on lung adenocarcinoma (LUAD) through a comprehensive strategy integrating network pharmacology, metabolomics and molecular biology verification.

METHODS

The putative targets of bufalin were discerned from PharmMapper and Swiss Target Prediction database. LUAD-related targets were obtained by target filtering of GeneCard database and data mining of GEO database. PPI network was constructed to screen the core targets, and their clinical significance was assessed through several public databases. GO and KEGG pathway analyses were performed to identify possible enrichment of genes with specific biological themes. Molecular docking and molecular dynamics (MD) simulation were employed to determine the correlation and binding pattern between bufalin and core targets. The potential mechanisms of bufalin acting on LUAD, as predicted by network pharmacology analyses, were experimentally validated using in-vitro and in-vivo models. Finally, the effects of bufalin intervention on metabolite profile and metabolic pathway in LUAD nude mice were investigated by non-targeted metabolomics.

RESULTS

209 bufalin targets and 1082 LUAD-associated targets were harvested, of which 51 intersection targets were identified. 10 core targets including Akt1, STAT3, EGFR, CASP3 and SRC were picked out through network topology analysis, and they had a potent binding activity with bufalin as indicated by molecular docking and MD simulation. Hub module of PPI network was closely related to cell proliferation and apoptosis. GO and KEGG enrichment analyses suggested that bufalin exerted therapeutic effects on LUAD possibly by inhibiting proliferation and promoting apoptosis via PI3K/Akt, FoxO1 and MAPK/ERK pathways, which were confirmed by a series of in-vitro studies as well as HE, TUNEL and Ki-67 staining of tumor tissues. Further metabolomics analysis revealed that bufalin mainly regulated ABC transporter and remodeled AA metabolism, thereby contributing to the treatment of LUAD.

CONCLUSION

From molecular and metabolic perspective, the present study not only provided a unique insight into the possible mechanisms of bufalin against LUAD after successfully filtering out associated key target genes, differential endogenous metabolites, and signaling pathways, but also proposed a novel promising therapeutic strategy for LUAD.

Target c-Myc to treat pancreatic cancer

C-Myc overexpression is a common finding in pancreatic cancer and predicts the aggressive behavior of cancer cells. It binds to the promoter of different genes, thereby regulating their transcription. C-Myc is downstream of KRAS and interacts with several oncogenic and proliferative pathways in pancreatic cancer. C-Myc enhances aerobic glycolysis in cancer cells and regulates glutamate biosynthesis from glutamine. It provides enough energy for cancer cells' metabolism and sufficient substrate for the synthesis of organic molecules. C-Myc overexpression is associated with chemoresistance, intra-tumor angiogenesis, epithelial-mesenchymal transition (EMT), and metastasis in pancreatic cancer. Despite its title, c-Myc is not "undruggable" and recent studies unveiled that it can be targeted, directly or indirectly. Small molecules that accelerate c-Myc ubiquitination and degradation have been effective in preclinical studies. Small molecules that hinder c-Myc-MAX heterodimerization or c-Myc/MAX/DNA complex formation can functionally inhibit c-Myc. In addition, c-Myc can be targeted through transcriptional, post-transcriptional, and translational modifications.

Cancer Stem Cells and the Tumor Microenvironment: Targeting the Critical Crosstalk through Nanocarrier Systems

The physiological state of the tumor microenvironment (TME) plays a central role in cancer development due to multiple universal features that transcend heterogeneity and niche specifications, like promoting cancer progression and metastasis. As a result of their preponderant involvement in tumor growth and maintenance through several microsystemic alterations, including hypoxia, oxidative stress, and acidosis, TMEs make for ideal targets in both diagnostic and therapeutic ventures. Correspondingly, methodologies to target TMEs have been investigated this past decade as stratagems of significant potential in the genre of focused cancer treatment. Within targeted oncotherapy, nanomedical derivates-nanocarriers (NCs) especially-have emerged to present notable prospects in enhancing targeting specificity. Yet, one major issue in the application of NCs in microenvironmental directed therapy is that TMEs are too broad a spectrum of targeting possibilities for these carriers to be effectively employed. However, cancer stem cells (CSCs) might portend a solution to the above conundrum: aside from being quite heavily invested in tumorigenesis and therapeutic resistance, CSCs also show self-renewal and fluid clonogenic properties that often define specific TME niches. Further scrutiny of the relationship between CSCs and TMEs also points towards mechanisms that underly tumoral characteristics of metastasis, malignancy, and even resistance. This review summarizes recent advances in NC-enabled targeting of CSCs for more holistic strikes against TMEs and discusses both the current challenges that hinder the clinical application of these strategies as well as the avenues that can further CSC-targeting initiatives. Central role of CSCs in regulation of cellular components within the TME.

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.

Antitumor Effects of 10058-F4 and Curcumin in Combination Therapy for Pancreatic Cancer In Vitro and In Vivo

Background

Pancreatic cancer (PC) stands out as one of the most lethal cancers. Due to late diagnosis, only a fraction of patients can be resected. Although it still has significant adverse effects and poor results, the treatment is connected with better overall survival than the prior treatment. Thus, new alternative therapy for advanced PC is needed. Materials/Methods. The impact of 10058-F4 and curcumin combination therapy on apoptosis and cell growth in SW1990 pancreatic cancer cells were determined in vitro using the CCK-8 assay and flow cytometry of Annexin V-FITC/PI, and the in vivo antitumor effect was determined utilizing SW1990-bearing pancreatic tumor mouse models induced by subcutaneous implantation.

Results

At concentrations of (10 mol/L+2 mol/L), 10058-F4+curcumin obtained the highest rate of SW1990 cell death, and they had a beneficial effect on SW1990 pancreatic tumor-bearing animals. Furthermore, c-Myc, Akt phosphorylation, and the expression of apoptosis-related molecular were reduced, and the combination therapy modified the expression of apoptosis-related molecular.

Conclusions

In vitro and in vivo, the combination of 10058-F4 plus curcumin has antipancreatic cancer actions that are substantially effective.

Growth Inhibition and Apoptotic Effect of Pine Extract and Abietic Acid on MCF-7 Breast Cancer Cells via Alteration of Multiple Gene Expressions Using In Vitro Approach

In vitro anti-proliferative activity of Pinus palustris extract and its purified abietic acid was assessed against different human cancer cell lines (HepG-2, MCF-7 and HCT-116) compared to normal WI-38 cell line. Abietic acid showed more promising IC50 values against MCF-7 cells than pine extract (0.06 µg/mL and 0.11 µM, respectively), with insignificant cytotoxicity toward normal fibroblast WI-38 cells. Abietic acid triggered both G2/M cell arrest and subG0-G1 subpopulation in MCF-7, compared to SubG0-G1 subpopulation arrest only for the extract. It also induced overexpression of key apoptotic genes (Fas, FasL, Casp3, Casp8, Cyt-C and Bax) and downregulation of both proliferation (VEGF, IGFR1, TGF-β) and oncogenic (C-myc and NF-κB) genes. Additionally, abietic acid induced overexpression of cytochrome-C protein. Furthermore, it increased levels of total antioxidants to diminish carcinogenesis and chemotherapy resistance. P. palustris is a valuable source of active abietic acid, an antiproliferative agent to MCF-7 cells through induction of apoptosis with promising future anticancer agency in breast cancer therapy.

Novel Strategies for Solubility and Bioavailability Enhancement of Bufadienolides

Toad venom contains a large number of bufadienolides, which have a variety of pharmacological activities, including antitumor, cardiovascular, anti-inflammatory, analgesic and immunomodulatory effects. The strong antitumor effect of bufadienolides has attracted considerable attention in recent years, but the clinical application of bufadienolides is limited due to their low solubility and poor bioavailability. In order to overcome these shortcomings, many strategies have been explored, such as structural modification, solid dispersion, cyclodextrin inclusion, microemulsion and nanodrug delivery systems, etc. In this review, we have tried to summarize the pharmacological activities and structure-activity relationship of bufadienolides. Furthermore, the strategies for solubility and bioavailability enhancement of bufadienolides also are discussed. This review can provide a basis for further study on bufadienolides.

Prognostic Stratification Based on HIF-1 Signaling for Evaluating Hypoxic Status and Immune Infiltration in Pancreatic Ductal Adenocarcinomas

Pancreatic ductal adenocarcinoma (PDAC) has a hypoxic and desmoplastic tumor microenvironment (TME), leading to treatment failure. We aimed to develop a prognostic classifier to evaluate hypoxia status and hypoxia-related molecular characteristics of PDAC. In this study, we classified PDAC into three clusters based on 16 known hypoxia-inducible factor 1 (HIF-1)-related genes. Nine differentially expressed genes were identified to construct an HIF-1 score system, whose predictive efficacy was evaluated. Furthermore, we investigated oncogenic pathways and immune-cell infiltration status of PDAC with different scores. The C-index of the HIF-1score system for OS prediction in the meta-PDAC cohort and the other two validation cohorts were 0.67, 0.63, and 0.65, respectively, indicating that it had a good predictive value for patient survival. Furthermore, the area under the curve (AUC) of the receiver operating characteristic (ROC) curve of the HIF-1α score system for predicting 1-, 3-, and 4-year OS indicated the HIF-1α score system had an optimal discrimination of prognostic prediction for PDAC. Importantly, our model showed superior predictive ability compared to previous hypoxia signatures. We also classified PDAC into HIF-1 scores of low, medium, and high groups. Then, we found high enrichment of glycolysis, mTORC1 signaling, and MYC signaling in the HIF-1 score high group, whereas the cGMP metabolic process was activated in the low score group. Of note, analysis of public datasets and our own dataset showed a high HIF-1 score was associated with high immunosuppressive TME, evidenced by fewer infiltrated CD8⁺ T cells, B cells, and type 1 T-helper cells and reduced cytolytic activity of CD8⁺ T cells. In summary, we established a specific HIF-1 score system to discriminate PDAC with various hypoxia statuses and immune microenvironments. For highly hypoxic and immunosuppressive tumors, a combination treatment strategy should be considered in the future.

Halofuginone Sensitizes Lung Cancer Organoids to Cisplatin via Suppressing PI3K/AKT and MAPK Signaling Pathways

Lung cancer is the leading cause of cancer death worldwide. Cisplatin is the major DNA-damaging anticancer drug that cross-links the DNA in cancer cells, but many patients inevitably develop resistance with treatment. Identification of a cisplatin sensitizer might postpone or even reverse the development of cisplatin resistance. Halofuginone (HF), a natural small molecule isolated from Dichroa febrifuga, has been found to play an antitumor role. In this study, we found that HF inhibited the proliferation, induced G0/G1 phase arrest, and promoted apoptosis in lung cancer cells in a dose-dependent manner. To explore the underlying mechanism of this antitumor effect of halofuginone, we performed RNA sequencing to profile transcriptomes of NSCLC cells treated with or without halofuginone. Gene expression profiling and KEGG analysis indicated that PI3K/AKT and MAPK signaling pathways were top-ranked pathways affected by halofuginone. Moreover, combination of cisplatin and HF revealed that HF could sensitize the cisplatin-resistant patient-derived lung cancer organoids and lung cancer cells to cisplatin treatment. Taken together, this study identified HF as a cisplatin sensitizer and a dual pathway inhibitor, which might provide a new strategy to improve prognosis of patients with cisplatin-resistant lung cancer.

Bruceine D inhibits HIF-1α-mediated glucose metabolism in hepatocellular carcinoma by blocking ICAT/β-catenin interaction

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths, characterized by highly hypoxic tumor microenvironment. Hypoxia-inducible factor-1α (HIF-1α) is a major regulator involved in cellular response to changes of oxygen levels, supporting the adaptation of tumor cells to hypoxia. Bruceine D (BD) is an isolated natural quassinoid with multiple anti-cancer effects. Here, we identified BD could significantly inhibit the HIF-1α expression and its subsequently mediated HCC cell metabolism. Using biophysical proteomics approaches, we identified inhibitor of β-catenin and T-cell factor (ICAT) as the functional target of BD. By targeting ICAT, BD disrupted the interaction of β-catenin and ICAT, and promoted β-catenin degradation, which in turn induced the decrease of HIF-1α expression. Furthermore, BD could inhibit HCC cells proliferation and tumor growth in vivo, and knockdown of ICAT substantially increased resistance to BD treatment in vitro. Our data highlight the potential of BD as a modulator of β-catenin/HIF-1α axis mediated HCC metabolism.

Bufalin suppresses tumour microenvironment-mediated angiogenesis by inhibiting the STAT3 signalling pathway

BACKGROUND

Antiangiogenic therapy has increasingly become an important strategy for the treatment of colorectal cancer. Recent studies have shown that the tumour microenvironment (TME) promotes tumour angiogenesis. Bufalin is an active antitumour compound whose efficacy has been indicated by previous studies. However, there are very few studies on the antiangiogenic effects of bufalin.

METHODS

Herein, human umbilical vein endothelial cell (HUVEC) tube formation, migration and adhesion tests were used to assess angiogenesis in vitro. Western blotting and quantitative PCR were used to detect relevant protein levels and mRNA expression levels. A subcutaneous xenograft tumour model and a hepatic metastasis model were established in mice to investigate the influence of bufalin on angiogenesis mediated by the TME in vivo.

RESULTS

We found that angiogenesis mediated by cells in the TME was significantly inhibited in the presence of bufalin. The results demonstrated that the proangiogenic genes in HUVECs, such as VEGF, PDGFA, E-selectin and P-selectin, were downregulated by bufalin and that this downregulation was mediated by inhibition of the STAT3 pathway. Overexpression of STAT3 reversed the inhibitory effects of bufalin on angiogenesis. Furthermore, there was little reduction in angiogenesis when bufalin directly acted on the cells in the tumour microenvironment.

CONCLUSION

Our findings demonstrate that bufalin suppresses tumour microenvironment-mediated angiogenesis by inhibiting the STAT3 signalling pathway in vascular endothelial cells, revealing that bufalin may be used as a new antiangiogenic adjuvant therapy medicine to treat colorectal cancer.

Noncoding RNAs Associated with Therapeutic Resistance in Pancreatic Cancer

Therapeutic resistance is an inevitable impediment towards effective cancer therapies. Evidence accumulated has shown that the signaling pathways and related factors are fundamentally responsible for therapeutic resistance via regulating diverse cellular events, such as epithelial-to-mesenchymal transition (EMT), stemness, cell survival/apoptosis, autophagy, etcetera. Noncoding RNAs (ncRNAs) have been identified as essential cellular components in gene regulation. The expression of ncRNAs is altered in cancer, and dysregulated ncRNAs participate in gene regulatory networks in pathological contexts. An in-depth understanding of molecular mechanisms underlying the modulation of therapeutic resistance is required to refine therapeutic benefits. This review presents an overview of the recent evidence concerning the role of human ncRNAs in therapeutic resistance, together with the feasibility of ncRNAs as therapeutic targets in pancreatic cancer.

The Role of the CXCL12/CXCR4/CXCR7 Chemokine Axis in Cancer

Chemokines are a family of small, secreted cytokines which regulate a variety of cell functions. The C-X-C motif chemokine ligand 12 (CXCL12) binds to C-X-C chemokine receptor type 4 (CXCR4) and C-X-C chemokine receptor type 7 (CXCR7). The interaction of CXCL12 and its receptors subsequently induces downstream signaling pathways with broad effects on chemotaxis, cell proliferation, migration, and gene expression. Accumulating evidence suggests that the CXCL12/CXCR4/CXCR7 axis plays a pivotal role in tumor development, survival, angiogenesis, metastasis, and tumor microenvironment. In addition, this chemokine axis promotes chemoresistance in cancer therapy via complex crosstalk with other pathways. Multiple small molecules targeting CXCR4/CXCR7 have been developed and used for preclinical and clinical cancer treatment. In this review, we describe the roles of the CXCL12/CXCR4/CXCR7 axis in cancer progression and summarize strategies to develop novel targeted cancer therapies.

Identification of Cardiac Glycosides as Novel Inhibitors of eIF4A1-Mediated Translation in Triple-Negative Breast Cancer Cells

The eukaryotic translation initiation factor 4F complex (eIF4F) is a potential chemotherapeutic target in triple-negative breast cancer (TNBC). This complex regulates cap-dependent translational initiation and consists of three core proteins: eIF4E, eIF4G, and eIF4A1. In this study, we focus on repositioning compounds as novel inhibitors of eIF4A1-mediated translation. In order to accomplish this goal, a modified synthetic reporter assay was established. More specifically, a (CGG)₄ motif, which confers eIF4A dependency, was incorporated into the 5'-leader region of a luciferase-tdTomato lentiviral reporter construct. The Prestwick Chemical Library was then screened in multiple TNBC cell lines by measuring the tdTomato fluorescent intensity. We identified several cardiac glycosides as potential inhibitors of eIF4A1-mediated translation. Based on our studies, we find that cardiac glycosides inhibit the expression of eIF4A1. To identify a potential mechanism by which this was occurring, we utilized the Integrative Library of Integrated Network-Based Cellular Signatures (iLINCS). Our pursuits led us to the discovery that cardiac glycosides also decrease levels of c-MYC. Quantitative PCR confirmed that decreases in c-MYC and eIF4A were occurring at the transcriptional level. As such, disruption of the eIF4A1-c-MYC axis may be a viable approach in the treatment of TNBC. The novel combination of rocaglamide A and digoxin exhibited synergistic anti-cancer activity against TNBC cells in vitro. The findings in this study and others are important for formulating potential combination chemotherapies against eIF4A1 in vivo. Thus, drug repositioning may be one classical approach to successfully target eIF4A1 in TNBC patients.