Betulinic acid inhibits colon cancer cell and tumor growth and induces proteasome-dependent and -independent downregulation of specificity proteins (Sp) transcription factors

Polyphenol Intake in Elderly Patients: A Novel Approach to Counteract Colorectal Cancer Risk?

Colorectal cancer (CRC) accounts for approximately 10% of all cancers worldwide with an incidence of approximately 60% in patients older than 70 years. In the elderly, the definition of a better therapeutic strategy depends on several factors including the patient's frailty and comorbidity status, life expectancy, and chemotherapy tolerance. In older patients, adverse drug reactions require a reduction in the dose of treatment, resulting in worse oncologic outcomes. In recent years, an increasing number of studies have focused on the potential effects of polyphenols on human health and their use in cancer therapy. In this comprehensive review, we searched the major databases and summarized experimental data of the most important polyphenols in the CRC chemoprevention, with a focus on the molecular mechanisms involved and the antitumor effects in the elderly population. In vitro and in vivo studies have shown that polyphenols exert chemopreventive activity by modulating cell signaling, resulting in the inhibition of cancer development or progression. However, the efficacy seen in experimental studies has not been confirmed in clinical trials, mainly due to their low bioavailability and non-toxic doses. Further research is needed to increase polyphenol bioavailability and reduce side effects in order to suggest their possible use to increase the efficacy of chemotherapeutic treatment.

Enhanced ZBTB10 expression induced by betulinic acid inhibits gastric cancer progression by inactivating the ARRDC3/ITGB4/PI3K/AKT pathway

BACKGROUND

Gastric cancer (GC) ranks as the fourth leading cause of cancer-related deaths worldwide, with most patients diagnosed at advanced stages due to the absence of reliable early detection biomarkers.

METHODS

RNA-sequencing was conducted to identify the differentially expressed genes between GC tissues and adjacent normal tissues. CCK8, EdU, colony formation, transwell, flow cytometry and xenograft assays were adopted to explore the biological function of ZBTB10 and betulinic acid (BA) in GC progression. RNA-sequencing and phospho-proteomic profiling were performed to analyze the signaling pathways associated with ZBTB10-inhibiting GC progression. Chromatin immunoprecipitation, Co-immunoprecipitation and luciferase reporter assay were employed to elucidate the potential molecular regulatory mechanisms of ZBTB10 in GC.

RESULTS

ZBTB10 was one of the most significantly downregulated genes in GC tissues, and higher expression levels of ZBTB10 was correlated with better prognosis in patients with GC. Functional studies revealed that ZBTB10 overexpression and BA inhibited GC progression both in vitro and in vivo. Mechanistically, ZBTB10 enhanced ARRDC3 expression by binding to a specific response element in the ARRDC3 promoter region. Elevated ARRDC3 then directly interacted with β-4 integrin (ITGB4), leading to its ubiquitination and degradation. This cascade ultimately resulted in the downregulation of PI3K and AKT phosphorylation level. Moreover, ZBTB10 was a key target for BA in GC and BA inhibited GC progression through regulating the ZBTB10/ARRDC3/ITGB4/PI3K/AKT axis.

CONCLUSIONS

Our findings reveal that BA holds promise as an effective therapeutic strategy for GC, and the ZBTB10/ARRDC3/ITGB4/PI3K/AKT axis may serve as a novel diagnostic and therapeutic target.

Cellular and molecular mechanisms underlying the potential of betulinic acid in cancer prevention and treatment

BACKGROUND

Betulinic acid (BA), which is a pentacyclic triterpenoid found in the bark of plane, birch, and eucalyptus trees, has emerged as a compound of significant interest in scientific research due to its potential therapeutic applications. BA has a range of well-documented pharmacological and biological effects, including antibacterial, immunomodulatory, diuretic, antiviral, antiparasitic, antidiabetic, and anticancer activities. Although numerous research studies have explored the potential anticancer effects of BA, there is a noticeable gap in the literature, highlighting the need for a more up-to-date and comprehensive evaluation of BA's anticancer potential.

PURPOSE

The aim of this work is to critically assess the reported cellular and molecular mechanisms underlying the cancer preventive and therapeutic effects of BA.

METHODS

Relevant research on the inhibitory effects of BA against cancerous cells was searched using Science Direct, Scopus, Web of Science, and PubMed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

The anticancer properties of BA are mediated by the activation of cell death and cell cycle arrest, production of reactive oxygen species, increased mitochondrial permeability, modulation of nuclear factor-κB and Bcl-2 family signaling. Emerging evidence also underscores the combined anticancer effects of BA with other natural bioactive compounds or approved drugs. Notably, several novel BA nanoformulations have been found to exhibit encouraging antineoplastic activities.

CONCLUSION

BA, whether used alone or in combination, or as a form of nanoformulation, shows significant potential for cancer prevention and treatment. Nevertheless, further detailed studies are necessary to confirm the therapeutic effectiveness of this natural compound.

FNDC5 inhibits autophagy of bone marrow mesenchymal stem cells and promotes their survival after transplantation by downregulating Sp1

Regenerative therapy based on mesenchymal stem cells (MSCs) has great promise to achieve functional recovery in cerebral infarction patients. However, the survival rate of transplanted MSCs is extremely low because of destructive autophagy caused by the harsh ischemic microenvironment in cerebral infarct tissue. The mechanism by which fibronectin type III domain protein 5 (FNDC5) regulates autophagy of transplanted bone marrow-MSCs (BMSCs) following ischemic injury needs to be elucidated. In this study, we confirmed that FNDC5 promotes the survival of transplanted BMSCs in a rat cerebral infarction model. Furthermore, bioinformatic analysis and verification experiments revealed the transcription factor, Sp1, to be a key mediator of autophagy regulation by FNDC5. FNDC5 significantly inhibited BMSC autophagy by down-regulating Sp1 and the autophagy-related Sp1-target gene, ULK2. Transplanted BMSCs overexpressing FNDC5 (BMSCs-OE-FNDC5) promoted neurovascular proliferation and alleviated ischemic brain injury in cerebral infarct model rats. However, the increased survival and enhanced neuroprotective effect of transplanted BMSCs-OE-FNDC5 were reversed by simultaneous overexpression of Sp1. Our data indicate a role for FNDC5 in BMSC survival and reveal a novel mechanism of transcription regulation through Sp1 for the autophagy-related gene ULK2. Modulation of FNDC5 may promote survival capacity and improve the therapeutic effect of BMSCs in various tissues following ischemia.

Betulinic acid in the treatment of breast cancer: Application and mechanism progress

Betulinic acid (BA) is a pentacyclic triterpene compound, which can be obtained by separation, chemical synthesis and biotransformation. BA has excellent biological activities, especially its role in the treatment of breast cancer deserves attention. Its mechanisms mainly include inducing mitochondrial oxidative stress, regulating specific protein (Sp) transcription factors, inhibiting breast cancer metastasis, inhibiting glucose metabolism and NF-κB pathway. In addition, BA can also increase the sensitivity of breast cancer cells to other chemotherapy drugs such as paclitaxel and reduce its toxic side effects. This article reviews the application and possible mechanism of BA in the treatment of breast cancer.

Bifunctionalized Betulinic Acid Conjugates with C-3-Monodesmoside and C-28-Triphenylphosphonium Moieties with Increased Cancer Cell Targetability

A convenient synthesis is presented for a new class of bioactive bifunctionalized conjugates of lupane-type triterpenoids with triphenylphosphonium (TPP) and glycopyranosyl targeting moieties. The main synthesis steps include glycosylation of haloalkyl esters of the triterpene acid at the C-3 position by the imidate derivatives of glycopyranose followed by the product modification at the C-28 position with triphenylphosphine. The conjugates of betulinic acid (BetA) with TPP and d-glucose, l-rhamnose, or d-mannose moieties were thus synthesized as potential next-generation BetA-derived anticancer compounds. LC-MS/MS analysis in glucose-free physiological solution indicated that the glycosides showed better accumulation in PC-3 prostate cancer cells than both BetA and TPP-BetA conjugate, while the transporting effect of monosaccharide residues increased as follows: d-mannose < l-rhamnose ≈ d-glucose. At saturated concentrations, the glycosides caused a disturbing effect on mitochondria with a more drastic drop in transmembrane potential but weaker overproduction of mitochondrial reactive oxygen species (ROS) compared to TPP-BetA conjugate. Cytotoxicity of the glycosides in culture medium was comparable with or higher than that of the nonglycosylated conjugate, depending on the cancer cell line, whereas the compounds were less active toward primary fibroblasts. Glycosylation tended to increase pro-apoptotic and decrease pro-autophagic activities of the BetA derivatives. Cytotoxicity of the synthesized glycosides was considered in comparison with the summarized data on the natural and modified BetA glycosides. The results obtained are important for the development of bifunctionalized conjugates of triterpenoids with an increased cancer cell targetability.

Connection between Radiation-Regulating Functions of Natural Products and miRNAs Targeting Radiomodulation and Exosome Biogenesis

Exosomes are cell-derived membranous structures primarily involved in the delivery of the payload to the recipient cells, and they play central roles in carcinogenesis and metastasis. Radiotherapy is a common cancer treatment that occasionally generates exosomal miRNA-associated modulation to regulate the therapeutic anticancer function and side effects. Combining radiotherapy and natural products may modulate the radioprotective and radiosensitizing responses of non-cancer and cancer cells, but there is a knowledge gap regarding the connection of this combined treatment with exosomal miRNAs and their downstream targets for radiation and exosome biogenesis. This review focuses on radioprotective natural products in terms of their impacts on exosomal miRNAs to target radiation-modulating and exosome biogenesis (secretion and assembly) genes. Several natural products have individually demonstrated radioprotective and miRNA-modulating effects. However, the impact of natural-product-modulated miRNAs on radiation response and exosome biogenesis remains unclear. In this review, by searching through PubMed/Google Scholar, available reports on potential functions that show radioprotection for non-cancer tissues and radiosensitization for cancer among these natural-product-modulated miRNAs were assessed. Next, by accessing the miRNA database (miRDB), the predicted targets of the radiation- and exosome biogenesis-modulating genes from the Gene Ontology database (MGI) were retrieved bioinformatically based on these miRNAs. Moreover, the target-centric analysis showed that several natural products share the same miRNAs and targets to regulate radiation response and exosome biogenesis. As a result, the miRNA-radiomodulation (radioprotection and radiosensitization)-exosome biogenesis axis in regard to natural-product-mediated radiotherapeutic effects is well organized. This review focuses on natural products and their regulating effects on miRNAs to assess the potential impacts of radiomodulation and exosome biogenesis for both the radiosensitization of cancer cells and the radioprotection of non-cancer cells.

Quercetin's Dual Mode of Action to Counteract the Sp1-miR-27a Axis in Colorectal Cancer Cells

Quercetin (Qc) inhibits cell proliferation and induces apoptosis in a variety of cancer cells. The molecular mechanism of action has not been fully elucidated; however, interplay with some miRNAs has been reported, specifically with miR-27a, an onco-miRNA overexpressed in several malignancies. Here, we show that Qc reduces cell viability and induces apoptosis in HCT116 and HT-29 colon cancer cells, by upregulating negative modulators of proliferation pathways such as Sprouty2, PTEN and SFRP1. These are targets of miR-27a whose high expression is reduced by Qc. Moreover, miR-23a, and miR-24-2, the two other components of the unique gene cluster, and the pri-miRNA transcript are reduced, evoking a transcriptional regulation of the entire cluster by Sp1. Mechanistically, we show that Qc is rapidly internalized and localizes in the nucleus, where it likely interacts with Sp1, inducing its proteasomal degradation. Sp1 is further repressed by ZBTB10, an Sp1 competitor for DNA binding that is an miR-27a target and whose levels increase following Qc. SP1 mRNA is also reduced, supporting the regulation of its own gene transcription. Finally, Sp1 knockdown elicits the impaired transcription of the entire cluster and the upregulation of the miR-27a targets, phenocopying the effects of Qc. Through this dual mode of action, Qc counteracts the protumoral Sp1-miR-27a axis, opening the way for novel therapies based on its association as neoadjuvant with known anticancer treatments.

Targeting Transcription Factor YY1 for Cancer Treatment: Current Strategies and Future Directions

Cancer represents a significant and persistent global health burden, with its impact underscored by its prevalence and devastating consequences. Whereas numerous oncogenes could contribute to cancer development, a group of transcription factors (TFs) are overactive in the majority of tumors. Targeting these TFs may also combat the downstream oncogenes activated by the TFs, making them attractive potential targets for effective antitumor therapeutic strategy. One such TF is yin yang 1 (YY1), which plays crucial roles in the development and progression of various tumors. In preclinical studies, YY1 inhibition has shown efficacy in inhibiting tumor growth, promoting apoptosis, and sensitizing tumor cells to chemotherapy. Recent studies have also revealed the potential of combining YY1 inhibition with immunotherapy for enhanced antitumor effects. However, clinical translation of YY1-targeted therapy still faces challenges in drug specificity and delivery. This review provides an overview of YY1 biology, its role in tumor development and progression, as well as the strategies explored for YY1-targeted therapy, with a focus on their clinical implications, including those using small molecule inhibitors, RNA interference, and gene editing techniques. Finally, we discuss the challenges and current limitations of targeting YY1 and the need for further research in this area.

Specificity Proteins (Sp) and Cancer

The specificity protein (Sp) transcription factors (TFs) Sp1, Sp2, Sp3 and Sp4 exhibit structural and functional similarities in cancer cells and extensive studies of Sp1 show that it is a negative prognostic factor for patients with multiple tumor types. In this review, the role of Sp1, Sp3 and Sp4 in the development of cancer and their regulation of pro-oncogenic factors and pathways is reviewed. In addition, interactions with non-coding RNAs and the development of agents that target Sp transcription factors are also discussed. Studies on normal cell transformation into cancer cell lines show that this transformation process is accompanied by increased levels of Sp1 in most cell models, and in the transformation of muscle cells into rhabdomyosarcoma, both Sp1 and Sp3, but not Sp4, are increased. The pro-oncogenic functions of Sp1, Sp3 and Sp4 in cancer cell lines were studied in knockdown studies where silencing of each individual Sp TF decreased cancer growth, invasion and induced apoptosis. Silencing of an individual Sp TF was not compensated for by the other two and it was concluded that Sp1, Sp3 and Sp4 are examples of non-oncogene addicted genes. This conclusion was strengthened by the results of Sp TF interactions with non-coding microRNAs and long non-coding RNAs where Sp1 contributed to pro-oncogenic functions of Sp/non-coding RNAs. There are now many examples of anticancer agents and pharmaceuticals that induce downregulation/degradation of Sp1, Sp3 and Sp4, yet clinical applications of drugs specifically targeting Sp TFs are not being used. The application of agents targeting Sp TFs in combination therapies should be considered for their potential to enhance treatment efficacy and decrease toxic side effects.

The complex network of transcription factors, immune checkpoint inhibitors and stemness features in colorectal cancer: A recent update

Cancer immunity is regulated by several mechanisms that include co-stimulatory and/or co-inhibitory molecules known as immune checkpoints expressed by the immune cells. In colorectal cancer (CRC), CTLA-4, LAG3, TIM-3 and PD-1 are the major co-inhibitory checkpoints involved in tumor development and progression. On the other hand, the deregulation of transcription factors and cancer stem cells activity plays a major role in the development of drug resistance and in the spread of metastatic disease in CRC. In this review, we describe how the modulation of such transcription factors affects the response of CRC to therapies. We also focus on the role of cancer stem cells in tumor metastasis and chemoresistance and discuss both preclinical and clinical approaches for targeting stem cells to prevent their tumorigenic effect. Finally, we provide an update on the clinical applications of immune checkpoint inhibitors in CRC and discuss the regulatory effects of transcription factors on the expression of the immune inhibitory checkpoints with specific focus on the PD-1 and PD-L1 molecules.

Mechanism of ferroptosis in traditional chinese medicine for clinical treatment: A review

Ferroptosis is an iron-dependent regulation of cell death driven by lipid peroxidation, which is intracellularly dependent on iron and independent of other metals, and morphologically, biochemically, and genetically distinct from apoptosis, necrosis, and autophagy. Ferroptosis is closely related to physiological and pathological processes, such as development, aging, and immunity, and it plays an important role in a variety of diseases. In many departments, traditional Chinese medicine plays an increasingly important role in their clinical treatment. In recent years, an increasing number of studies have been conducted on the mechanism of ferroptosis in traditional Chinese medicine. However, the role of ferroptosis in the clinical treatment of traditional Chinese medicine requires further exploration. This article mainly introduces the application of ferroptosis in studies of the mechanism of traditional Chinese medicine to help clinicians understand the current status of traditional Chinese medicine therapy for the treatment of ferroptosis-related diseases.

Multifunctional Roles of Betulinic Acid in Cancer Chemoprevention: Spotlight on JAK/STAT, VEGF, EGF/EGFR, TRAIL/TRAIL-R, AKT/mTOR and Non-Coding RNAs in the Inhibition of Carcinogenesis and Metastasis

The pursual of novel anticancer molecules from natural sources has gained worthwhile appreciation, and a significant fraction of conceptual knowledge has revolutionized our understanding about heterogeneous nature of cancer. Betulinic acid has fascinated interdisciplinary researchers due to its tremendous pharmacological properties. Ground-breaking discoveries have unraveled previously unprecedented empirical proof-of-concept about momentous chemopreventive role of betulinic acid against carcinogenesis and metastasis. Deregulation of cell signaling pathways has been reported to play a linchpin role in cancer progression and colonization of metastatically competent cancer cells to the distant organs for the development of secondary tumors. Importantly, betulinic acid has demonstrated unique properties to mechanistically modulate oncogenic transduction cascades. In this mini-review, we have attempted to provide a sophisticated compendium of regulatory role of betulinic acid in cancer chemoprevention. We have partitioned this multi-component review into different sections in which we summarized landmark research-works which highlighted betulinic acid mediated regulation of JAK/STAT, VEGF, EGF/EGFR, TRAIL/TRAIL-R, AKT/mTOR and ubiquitination pathways in the inhibition of cancer. In parallel, betulinic acid mediated regulation of signaling cascades and non-coding RNAs will be critically analyzed in cell culture and animal model studies. Better comprehension of the pharmaceutical features of betulinic acid and mapping of the existing knowledge gaps will be valuable in the translatability of preclinical studies into rationally designed clinical trials.

Betulinic acid: A natural promising anticancer drug, current situation, and future perspectives

Natural products serve as the single most productive source for the discovery of drugs and pharmaceutical leads. Among the various chemicals derived from microbes, plants, and animals, phytochemicals have emerged as potential candidates for the development of anticancer drugs due to their structural diversities, complexities, and pleiotropic effects. Herein, we discuss betulinic acid (BA), a ubiquitously distributed lupane structured pentacyclic triterpenoid, scrutinized as a promising natural agent for the prevention, suppression, and management of various human malignancies. Ease of availability, common occurrences, cell-specific cytotoxicity, and astonishing selectivity are the important factors that contribute to the development of BA as an anticancer agent. The current review delineates the mechanistic framework of BA-mediated cancer suppression through the modulation of multiple signaling pathways and also summarizes the key outcomes of BA in preclinical investigations.

Targeting transforming growth factor-β signalling for cancer prevention and intervention: Recent advances in developing small molecules of natural origin

BACKGROUND

Cancer is the world's second leading cause of death, but a significant advancement in cancer treatment has been achieved within the last few decades. However, major adverse effects and drug resistance associated with standard chemotherapy have led towards targeted treatment options.

OBJECTIVES

Transforming growth factor-β (TGF-β) signaling plays a key role in cell proliferation, differentiation, morphogenesis, regeneration, and tissue homeostasis. The prime objective of this review is to decipher the role of TGF-β in oncogenesis and to evaluate the potential of various natural and synthetic agents to target this dysregulated pathway to confer cancer preventive and anticancer therapeutic effects.

METHODS

Various authentic and scholarly databases were explored to search and obtain primary literature for this study. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) criteria was followed for the review.

RESULTS

Here we provide a comprehensive and critical review of recent advances on our understanding of the effect of various bioactive natural molecules on the TGF-β signaling pathway to evaluate their full potential for cancer prevention and therapy.

CONCLUSION

Based on emerging evidence as presented in this work, TGF-β-targeting bioactive compounds from natural sources can serve as potential therapeutic agents for prevention and treatment of various human malignancies.

Caspase-Mediated Cleavage of the Transcription Factor Sp3: Possible Relevance to Cancer and the Lytic Cycle of Kaposi's Sarcoma-Associated Herpesvirus

The open reading frame 50 (ORF50) protein of Kaposi's sarcoma-associated herpesvirus (KSHV) is the master regulator essential for initiating the viral lytic cycle. Previously, we have demonstrated that the ORF50 protein can cooperate with Sp3 to synergistically activate a set of viral and cellular gene promoters through highly conserved ORF50-responsive elements that harbor a Sp3-binding motif. Herein, we show that Sp3 undergoes proteolytic cleavage during the viral lytic cycle, and the cleavage of Sp3 is dependent on caspase activation. Since similar cleavage patterns of Sp3 could be detected in both KSHV-positive and KSHV-negative lymphoma cells undergoing apoptosis, the proteolytic cleavage of Sp3 could be a common event during apoptosis. Mutational analysis identifies 12 caspase cleavage sites in Sp3, which are situated at the aspartate (D) positions D17, D19, D180, D273, D275, D293, D304 (or D307), D326, D344, D530, D543, and D565. Importantly, we noticed that three stable Sp3 C-terminal fragments generated through cleavage at D530, D543, or D565 encompass an intact DNA-binding domain. Like the full-length Sp3, the C-terminal fragments of Sp3 could still retain the ability to cooperate with ORF50 protein to activate specific viral and cellular gene promoters synergistically. Collectively, our findings suggest that despite the proteolytic cleavage of Sp3 under apoptotic conditions, the resultant Sp3 fragments may retain biological activities important for the viral lytic cycle or for cellular apoptosis. IMPORTANCE The ORF50 protein of Kaposi's sarcoma-associated herpesvirus (KSHV) is the key viral protein that controls the switch from latency to lytic reactivation. It is a potent transactivator that can activate target gene promoters via interacting with other cellular DNA-binding transcription factors, such as Sp3. In this report, we show that Sp3 is proteolytically cleaved during the viral lytic cycle, and up to 12 caspase cleavage sites are identified in Sp3. Despite the proteolytic cleavage of Sp3, several resulting C-terminal fragments that have intact zinc-finger DNA-binding domains still retain substantial influence in the synergy with ORF50 to activate specific gene promoters. Overall, our studies elucidate the caspase-mediated cleavage of Sp3 and uncover how ORF50 utilizes the cleavage fragments of Sp3 to transactivate specific viral and cellular gene promoters.

Bioactivity of betulinic acid nanoemulsions on skin carcinogenesis in transgenic mice K14E6

Alternative therapies for cancer treatment have been developed using bioactive compounds such as betulinic acid (BA). The objective of this study was to investigate the bioactivity of BA in its free form and compare it with its nano-encapsulated form under a skin carcinogenesis protocol in a genetically modified murine model. K14E6 and FVB mice were divided into four groups to be treated with free BA and with betulinic acid nanoemulsion (BANE). Lecithin enriched with medium chain fatty acids (MCFAs) was employed as an emulsifier to prepare the nanoemulsions with a mean droplet size of 40 nm. Skin tumors were induced by exposure to DMBA and TPA directly to the transgenic mice. Tumor development was completely inhibited by BANE and by 70% with free BA. This was validated by histological sections and the gene expression of the Cdk4 and Casp8 genes.

Role of Pentacyclic Triterpenoid Acids in the Treatment of Bladder Cancer

Bladder cancer carries a poor prognosis and has proven resistance to chemotherapy. Pentacyclic Triterpenoid Acids (PTAs) are natural bioactive compounds that have a well-known impact on cancer research because of their cytotoxic and chemopreventive activities. This review focuses on bladder cancer which can no longer be successfully treated by DNA damaging drugs. Unlike most of the existing drugs against bladder cancer, PTAs are non-toxic to normal cells. Collecting findings from both in vitro and in vivo studies, it has been concluded that PTAs may serve as promising agents in future bladder cancer therapy. In this review, the roles of various PTAs in bladder cancer have been explored, and their mechanisms of action in the treatment of bladder cancer have been described. Specific PTAs have been shortlisted from each of the chief skeletons of pentacyclic triterpenoids, which could be effective against bladder cancer because of their mode of action. This review thereby throws light on the multi targets and mechanisms of PTAs, which are responsible for their selective anticancer effects and provides guidelines for further research and development of new natural antitumor compounds.

Betulinic acid exerts antigenotoxic and anticarcinogenic activities via inhibition of COX-2 and PCNA in rodents

Phytochemicals have been suggested as an effective strategy for cancer prevention. Within this context, triterpene betulinic acid (BA) exhibits several biological properties but its chemopreventive effect has not been fully demonstrated. The present study investigated the antigenotoxic potential of BA against doxorubicin (DXR)-induced genotoxicity using the mouse peripheral blood micronucleus assay, as well as its anticarcinogenic activity against 1,2dimethylhydrazine (DMH)-induced colorectal lesions in rats. Micronuclei (MN) assay and aberrant crypt foci assay were used to assess the antigenotoxic and the anticarcinogenic potential, respectively. The molecular mechanisms underlying the anticarcinogenic activity of BA were evaluated by assessing anti-inflammatory (COX-2) and antiproliferative (PCNA) pathways. The results demonstrated that BA at the dose of 0.5 mg/kg bodyweight exerted antigenotoxic effects against DXR, with a reduction of 70.2% in the frequencies of chromosomal damage. Animals treated with BA showed a 64% reduction in the number of preneoplastic lesions when compared to those treated with the carcinogen alone. The levels of COX-2 and PCNA expression in the colon were significantly lower in animals treated with BA and DMH compared to those treated with the carcinogen alone. The chemopreventive effect of BA is related, at least in part, to its antiproliferative and anti-inflammatory activity, indicating a promising potential of this triterpene in anticancer therapies, especially for colorectal cancer.

Antitumorigenic effect of insect-derived peptide poecilocorisin-1 in human skin cancer cells through regulation of Sp1 transcription factor

Malignant melanoma is highly resistant to conventional treatments and is one of the most aggressive types of skin cancers. Conventional cancer treatments are limited due to drug resistance, tumor selectivity, and solubility. Therefore, new treatments with fewer side effects and excellent effects should be developed. In previous studies, we have analyzed antimicrobial peptides (AMPs), which showed antibacterial and anti-inflammatory effects in insects, and some AMPs also exhibited anticancer efficacy. Anticancer peptides (ACPs) are known to have fewer side effects and high anticancer efficacy. In this study, the insect-derived peptide poecilocorisin-1 (PCC-1) did not induce toxicity in the human epithelial cell line HaCaT, but its potential as an anticancer agent was confirmed through specific effects of antiproliferation, apoptosis, and cell cycle arrest in two melanoma cell lines, SK-MEL-28 and G361. Additionally, we discovered a novel anticancer mechanism of insect-derived peptides in melanoma through the regulation of transcription factor Sp1 protein, which is overexpressed in cancer, apoptosis, and cell cycle-related proteins. Taken together, this study aims to clarify the anticancer efficacy and safety of insect-derived peptides and to present their potential as future therapeutic agents.

A Review on Preparation of Betulinic Acid and Its Biological Activities

Betulinic acid, a pentacyclic triterpene, is distributed in a variety of plants, such as birch, eucalyptus and plane trees. It shows a wide spectrum of biological and pharmacological properties, such as anti-inflammatory, antibacterial, antiviral, antidiabetic, antimalarial, anti-HIV and antitumor effects. Among them, the antitumor activity of betulinic acid has been extensively studied. However, obtaining betulinic acid from natural resources can no longer meet the needs of medicine and nutrition, so methods such as chemical synthesis and microbial biotransformation have also been used to prepare betulinic acid. At the same time, with the development of synthetic biology and genetic engineering, and the elucidation of the biosynthetic pathways of terpenoid, the biosynthesis of betulinic acid has also been extensively researched. This article reviews the preparation of betulinic acid and its pharmacological activities, in order to provide a reference for the research and utilization of betulinic acid.

A Comprehensive Overview of Colon Cancer- A Grim Reaper of the 21st Century

A few decades ago, the incidence of colorectal cancer (CRC) was low and is now the fourth in the list of deadly cancers producing nearly a million deaths annually. A population that is aging along with risk factors such as smoking, obesity, sedentary lifestyle with little or no physical activity, and non-healthy food habits of developed countries can increase the risk of colorectal cancer. The balance in gut microbiota and the metabolites produced during bacterial fermentation within the host plays a significant role in regulating intestinal diseases as well as colorectal cancer development. Recent progress in the understanding of illness resulted in multiple treatment options such as surgery, radiation, and chemotherapy, including targeted therapy and multitherapies. The treatment plan for CRC depends on the location, stage and grade of cancer as well as genomic biomarker tests. Despite all the advancements made in the genetic and molecular aspects of the disease, the knowledge seems inadequate as the drug action as well as the wide variation in drug response did not appear strongly correlated with the individual molecular and genetic characteristics, which suggests the requirement of comprehensive molecular understanding of this complex heterogeneous disease. Furthermore, multitherapies or a broad spectrum approach, which is an amalgamation of the various promising as well as effective therapeutic strategies that can tackle heterogeneity and act on several targets of the disease, need to be validated in clinical studies. The latest treatment options have significantly increased the survival of up to three years in the case of advanced disease. The fact that colorectal cancer is developed from a polypoid precursor, as well as the symptoms of the disease that occur at an advanced stage, underlines how screening programs can help early detection and decrease mortality as well as morbidity from CRC.

Regulation of Cancer Metabolism by Deubiquitinating Enzymes: The Warburg Effect

Cancer is a disorder of cell growth and proliferation, characterized by different metabolic pathways within normal cells. The Warburg effect is a major metabolic process in cancer cells that affects the cellular responses, such as proliferation and apoptosis. Various signaling factors down/upregulate factors of the glycolysis pathway in cancer cells, and these signaling factors are ubiquitinated/deubiquitinated via the ubiquitin-proteasome system (UPS). Depending on the target protein, DUBs act as both an oncoprotein and a tumor suppressor. Since the degradation of tumor suppressors and stabilization of oncoproteins by either negative regulation by E3 ligases or positive regulation of DUBs, respectively, promote tumorigenesis, it is necessary to suppress these DUBs by applying appropriate inhibitors or small molecules. Therefore, we propose that the DUBs and their inhibitors related to the Warburg effect are potential anticancer targets.

Natural Products in the Prevention of Metabolic Diseases: Lessons Learned from the 20th KAST Frontier Scientists Workshop

The incidence of metabolic and chronic diseases including cancer, obesity, inflammation-related diseases sharply increased in the 21st century. Major underlying causes for these diseases are inflammation and oxidative stress. Accordingly, natural products and their bioactive components are obvious therapeutic agents for these diseases, given their antioxidant and anti-inflammatory properties. Research in this area has been significantly expanded to include chemical identification of these compounds using advanced analytical techniques, determining their mechanism of action, food fortification and supplement development, and enhancing their bioavailability and bioactivity using nanotechnology. These timely topics were discussed at the 20th Frontier Scientists Workshop sponsored by the Korean Academy of Science and Technology, held at the University of Hawaii at Manoa on 23 November 2019. Scientists from South Korea and the U.S. shared their recent research under the overarching theme of Bioactive Compounds, Nanoparticles, and Disease Prevention. This review summarizes presentations at the workshop to provide current knowledge of the role of natural products in the prevention and treatment of metabolic diseases.

Anti-Cancer and Immunomodulatory Activity of a Polyethylene Glycol-Betulinic Acid Conjugate on Pancreatic Cancer Cells

Drug delivery systems involving polymer therapeutics enhance drug potency by improved solubility and specificity and may assist in circumventing chemoresistance in pancreatic cancer (PC). We compared the effectiveness of the naturally occurring drug, betulinic acid (BA), alone and in a polymer conjugate construct of polyethylene glycol (PEG), (PEG-BA), on PC cells (MIA PaCa-2), a normal cell line (Vero) and on peripheral blood mononuclear cells (PBMCs). PEG-BA, was tested for its effect on cell death, immunomodulation and chemoresistance-linked signalling pathways. The conjugate was significantly more toxic to PC cells (p < 0.001, IC50 of 1.35 ± 0.11 µM) compared to BA (IC50 of 12.70 ± 0.34 µM), with a selectivity index (SI) of 7.28 compared to 1.4 in Vero cells. Cytotoxicity was confirmed by increased apoptotic cell death. PEG-BA inhibited the production of IL-6 by 4-5.5 fold compared to BA-treated cells. Furthermore, PEG-BA treatment of MIA PaCa-2 cells resulted in the dysregulation of crucial chemoresistance genes such as WNT3A, TXNRD1, SLC2A1 and GATA3. The dysregulation of chemoresistance-associated genes and the inhibition of cytokines such as IL-6 by the model polymer construct, PEG-BA, holds promise for further exploration in PC treatment.

Modified Gold Nanoparticles for Efficient Delivery of Betulinic Acid to Cancer Cell Mitochondria

Advances in nanomedicine have seen the adaptation of nanoparticles (NPs) for subcellular delivery for enhanced therapeutic impact and reduced side effects. The pivotal role of the mitochondria in apoptosis and their potential as a target in cancers enables selective induction of cancer cell death. In this study, we examined the mitochondrial targeted delivery of betulinic acid (BA) by the mitochondriotropic TPP⁺-functionalized epigallocatechin gallate (EGCG)-capped gold NPs (AuNPs), comparing the impact of polyethylene glycol (PEG) and poly-L-lysine-graft-polyethylene glycol (PLL-g-PEG) copolymer on delivery efficacy. This included the assessment of their cellular uptake, mitochondrial localization and efficacy as therapeutic delivery platforms for BA in the human Caco-2, HeLa and MCF-7 cancer cell lines. These mitochondrial-targeted nanocomplexes demonstrated significant inhibition of cancer cell growth, with targeted nanocomplexes recording IC₅₀ values in the range of 3.12–13.2 µM compared to that of the free BA (9.74–36.31 µM) in vitro, demonstrating the merit of mitochondrial targeting. Their mechanisms of action implicated high amplitude mitochondrial depolarization, caspases 3/7 activation, with an associated arrest at the G0/G1 phase of the cell cycle. This nano-delivery system is a potentially viable platform for mitochondrial-targeted delivery of BA and highlights mitochondrial targeting as an option in cancer therapy.

Ursolic acid disturbs ROS homeostasis and regulates survival-associated gene expression to induce apoptosis in intestinal cancer cells

Ursolic acid is a natural compound possessing several therapeutic properties including anticancer potential. In present study, cytotoxic and antimetastatic properties of ursolic acid were investigated in intestinal cancer cell lines INT-407 and HCT-116. The cells growth and number were decreased in a dose- and time-dependent manner in both the cell lines. It also increases reactive oxygen species levels in the cells in order to induce apoptosis. Ursolic acid was found to be a significant inhibitor of cancer cells migration and gene expression of migration markers FN1, CDH2, CTNNB1 and TWIST was also downregulated. Ursolic acid treatment downregulated the gene expression of survival factors BCL-2, SURVIVIN, NFKB and SP1, while upregulated the growth-restricting genes BAX, P21 and P53. These results indicate that ursolic acid has anticancer and antimetastatic properties against intestinal cancer. These properties could be beneficial in cancer treatment and could be used as complementary medicine.

Phytochemical Regulation of RNA in Treating Inflammatory Bowel Disease and Colon Cancer: Inspirations from Cell and Animal Studies

Recent studies suggest an important role for RNA, especially noncoding RNA, in inflammatory bowel disease (IBD) and colon cancer. Drug development based on regulating RNA rather than protein is a promising new area. Phytochemicals are naturally occurring plant-derived compounds with chemical diversity, biologic activity, easy availability, and low toxicity. Many phytochemicals have been shown to exert protective effects on IBD and colon cancer through modulation of RNAs. The aim of this study was to summarize the advancements of phytochemicals in regulating RNA for the treatment of IBD and colon cancer. This review involves many phytochemicals, including polyphenols, flavones, and alkaloids, which can influence various types of RNAs, including microRNA, long noncoding RNA, as well as messenger RNA, by influencing a variety of upstream molecules or regulating epigenetic processes. The limitation for many current studies is that the specific mechanisms of phytochemicals regulating RNA have not been fully uncovered. Accompanied by more identified functions of RNAs, especially noncoding RNA functions, the screening of RNA-regulating phytochemicals has presented challenges as well as opportunities for the prevention and treatment of IBD and colon cancer. SIGNIFICANCE STATEMENT: Noncoding RNAs, which constitute the majority of the human transcriptional genome, play a key role in the disease state and are considered as important therapeutic targets in inflammatory bowel disease (IBD) and colon cancer. Recent studies have shown that phytochemicals regulate the expression of many noncoding RNAs involved in IBD and colon cancer. Therefore, identifying the specific molecular mechanism of phytochemicals regulating noncoding RNA in disease models may result in novel and effective therapeutic opportunities.

Transcription factors in colorectal cancer: molecular mechanism and therapeutic implications

Colorectal cancer (CRC) is a major cause of cancer mortality worldwide, however, the molecular mechanisms underlying the pathogenesis of CRC remain largely unclear. Recent studies have revealed crucial roles of transcription factors in CRC development. Transcription factors essential for the regulation of gene expression by interacting with transcription corepressor/enhancer complexes and they orchestrate downstream signal transduction. Deregulation of transcription factors is a frequent occurrence in CRC, and the accompanying drastic changes in gene expression profiles play fundamental roles in multistep process of tumorigenesis, from cellular transformation, disease progression to metastatic disease. Herein, we summarized current and emerging key transcription factors that participate in CRC tumorigenesis, and highlighted their oncogenic or tumor suppressive functions. Moreover, we presented critical transcription factors of CRC, emphasized the major molecular mechanisms underlying their effect on signal cascades associated with tumorigenesis, and summarized of their potential as molecular biomarkers for CRC prognosis therapeutic response, as well as drug targets for CRC treatment. A better understanding of transcription factors involved in the development of CRC will provide new insights into the pathological mechanisms and reveal novel prognostic biomarkers and therapeutic strategies for CRC.

The Role of Oxidative Stress and Its Counteractive Utility in Colorectal Cancer (CRC)

An altered redox status accompanied by an elevated generation of reactive oxygen/nitrogen species (ROS/RNS) has been implicated in a number of diseases including colorectal cancer (CRC). CRC, being one of the most common cancers worldwide, has been reported to be associated with multiple environmental and lifestyle factors (e.g., dietary habits, obesity, and physical inactivity) and harboring heightened oxidative stress that results in genomic instability. Although under normal condition ROS regulate many signal transduction pathways including cell proliferation and survival, overwhelming of the antioxidant capacity due to metabolic abnormalities and oncogenic signaling leads to a redox adaptation response that imparts drug resistance. Nevertheless, excessive reliance on elevated production of ROS makes the tumor cells increasingly vulnerable to further ROS insults, and the abolition of such drug resistance through redox perturbation could be instrumental to preferentially eliminate them. The goal of this review is to demonstrate the evidence that links redox stress to the development of CRC and assimilate the most up-to-date information that would facilitate future investigation on CRC-associated redox biology. Concomitantly, we argue that the exploitation of this distinct biochemical property of CRC cells might offer a fresh avenue to effectively eradicate these cells.

Inhibition of Specificity Protein 1 Is Involved in Phloretin-Induced Suppression of Prostate Cancer

Phloretin is a flavonoid existed in various plants and has been reported to possess anticarcinogenic activity. However, the anticancer mechanism of phloretin in prostate cancer (PCa) remains unclear. Here, our in vitro and in vivo experimental data demonstrate that phloretin inhibits the phosphorylation and the activation of EGFR and then inhibits its downstream PI3K/AKT and MEK/ERK1/2 pathways in PCa cells. Inhibition of these two pathways further decreases expression of Sp1 by inhibiting Sp1 gene transcription, induces degradation of Sp1 protein by inhibiting GSK3β phosphorylation, suppresses nucleolin-enhanced translation of Sp1 mRNA by inhibiting nucleolin phosphorylation, and directly inactivates transcription activity of Sp1. Inhibition of Sp1 subsequently decreases the expression of Sp3/4, VEGF, and Survivin and then upregulates apoptosis-related proteins and downregulates cell cycle-related proteins in PCa cells. Finally, phloretin treatment in PCa cells induces cell growth inhibition and apoptosis, suggesting that phloretin may be an effective therapy compound in the treatment of prostate cancer.

Strategies to Modulate MicroRNA Functions for the Treatment of Cancer or Organ Injury

Cancer and organ injury-such as that occurring in the perioperative period, including acute lung injury, myocardial infarction, and acute gut injury-are among the leading causes of death in the United States and impose a significant impact on quality of life. MicroRNAs (miRNAs) have been studied extensively during the last two decades for their role as regulators of gene expression, their translational application as diagnostic markers, and their potential as therapeutic targets for disease treatment. Despite promising preclinical outcomes implicating miRNA targets in disease treatment, only a few miRNAs have reached clinical trials. This likely relates to difficulties in the delivery of miRNA drugs to their targets to achieve efficient inhibition or overexpression. Therefore, understanding how to efficiently deliver miRNAs into diseased tissues and specific cell types in patients is critical. This review summarizes current knowledge on various approaches to deliver therapeutic miRNAs or miRNA inhibitors and highlights current progress in miRNA-based disease therapy that has reached clinical trials. Based on ongoing advances in miRNA delivery, we believe that additional therapeutic approaches to modulate miRNA function will soon enter routine medical treatment of human disease, particularly for cancer or perioperative organ injury. SIGNIFICANCE STATEMENT: MicroRNAs have been studied extensively during the last two decades in cancer and organ injury, including acute lung injury, myocardial infarction, and acute gut injury, for their regulation of gene expression, application as diagnostic markers, and therapeutic potentials. In this review, we specifically emphasize the pros and cons of different delivery approaches to modulate microRNAs, as well as the most recent exciting progress in the field of therapeutic targeting of microRNAs for disease treatment in patients.

Glutathione S-Transferase pi-1 Knockdown Reduces Pancreatic Ductal Adenocarcinoma Growth by Activating Oxidative Stress Response Pathways

Glutathione S-transferase pi-1 (GSTP1) plays an important role in regulating oxidative stress by conjugating glutathione to electrophiles. GSTP1 is overexpressed in breast, colon, lung, and prostate tumors, where it contributes to tumor progression and drug resistance; however, the role of GSTP1 in pancreatic ductal adenocarcinoma (PDAC) is not well understood. Using shRNA, we knocked down GSTP1 expression in three different PDAC cell lines and determined the effect on cell proliferation, cell cycle progression, and reactive oxygen species (ROS) levels. Our results show GSTP1 knockdown reduces PDAC cell growth, prolongs the G0/G1 phase, and elevates ROS in PDAC cells. Furthermore, GSTP1 knockdown results in the increased phosphorylation of c-Jun N-terminal kinase (JNK) and c-Jun and the decreased phosphorylation of extracellular signal-regulated kinase (ERK), p65, the reduced expression of specificity protein 1 (Sp1), and the increased expression of apoptosis-promoting genes. The addition of the antioxidant glutathione restored cell viability and returned protein expression levels to those found in control cells. Collectively, these data support the working hypothesis that the loss of GSTP1 elevates oxidative stress, which alters mitogen-activated protein (MAP) kinases and NF-κB signaling, and induces apoptosis. In support of these in vitro data, nude mice bearing orthotopically implanted GSTP1-knockdown PDAC cells showed an impressive reduction in the size and weight of tumors compared to the controls. Additionally, we observed reduced levels of Ki-67 and increased expression of cleaved caspase-3 in GSTP1-knockdown tumors, suggesting GSTP1 knockdown impedes proliferation and upregulates apoptosis in PDAC cells. Together, these results indicate that GSTP1 plays a significant role in PDAC cell growth and provides support for the pursuit of GSTP1 inhibitors as therapeutic agents for PDAC.

Betulinic acid induces apoptosis and impairs migration and invasion in a mouse model of ovarian cancer

Betulinic acid (BA) was verified to possess plenty of biological activities including anti-tumor, anti-inflammatory and so on. In our research, we studied the growth inhibition, apoptosis promotion and metastasis resistance of ovarian cancer cells by BA. The result showed that BA showed a time- and dose-dependent inhibitory effect on ovarian cancer cell lines. SKOV3 cell line proliferation has a concentration- and time-dependently, which may be inhibited by BA. Furthermore, BA inhibited the metastasis of tumor cells remarkably by inhibiting epithelial-mesenchymal transition process. Beyond that, the weight and volume of subcutaneous tumor was distinctly suppressed by administration of BA in tumor-bearing mice of SKOV3 cells. Pathological and immunohistochemical tests showed that Ki-67⁺ and MMP-2⁺ cells were dramatically decreased after BA administration, indicating that BA can not only suppress proliferation, but also inhibit migration of tumor cells. Taken together, BA can be a valuable candidate drug for the treatment of ovarian cancer. PRACTICAL APPLICATIONS: Betulinic acid (BA) isolated from natural plants such as fenugreek, eucalyptus bulb and mulberry has been reported with many biological activities. Results from this study revealed that in vitro and in vivo BA-induced apoptosis and inhibited migration and invasion of human ovarian cancer cells. Therefore, BA from natural plants may be developed as a potential drug for inhibition the development of ovarian cancer cells.

Betulinic Acid Inhibits RANKL-Induced Osteoclastogenesis via Attenuating Akt, NF-κB, and PLCγ2-Ca2+ Signaling and Prevents Inflammatory Bone Loss

The increase of bone-resorbing osteoclast activity in bone remodeling is the major characteristic of various bone diseases. Thus, inhibiting osteoclastogenesis and bone-resorbing function may be an effective therapeutic target for bone diseases. Betulinic acid (BA), a natural plant-derived pentacyclic triterpenoid compound, is known to possess numerous pharmacological and biochemical properties including anti-inflammatory, anticancer, and antiadipogenic activity. However, the effect of BA on osteoclast differentiation and function in bone metabolism has not been demonstrated so far. In this study, we investigated whether BA could suppress RANKL-induced osteoclastogenesis and bone resorption. Interestingly, BA significantly suppressed osteoclastogenesis by decreasing the phosphorylation of Akt and IκB, as well as PLCγ2-Ca²⁺ signaling, in pathways involved in early osteoclastogenesis as well as through the subsequent suppression of c-Fos and NFATc1. The inhibition of these pathways by BA was once more confirmed by retrovirus infection of constitutively active (CA)-Akt and CA-Ikkβ retrovirus and measurement of Ca²⁺ influx. BA also significantly inhibited the expression of osteoclastogenesis-specific marker genes. Moreover, we found that BA administration restored the bone loss induced through acute lipopolysaccharide injection in mice by a micro-CT and histological analysis. Our findings suggest that BA is a potential therapeutic candidate for bone diseases involving osteoclasts.

Understanding the Role of the Transcription Factor Sp1 in Ovarian Cancer: from Theory to Practice

Ovarian cancer (OC) is one of the deadliest cancers among women contributing to high risk of mortality, mainly owing to delayed detection. There is no specific biomarker for its detection in early stages. However, recent findings show that over-expression of specificity protein 1 (Sp1) is involved in many OC cases. The ubiquitous transcription of Sp1 apparently mediates the maintenance of normal and cancerous biological processes such as cell growth, differentiation, angiogenesis, apoptosis, cellular reprogramming and tumorigenesis. Sp1 exerts its effects on cellular genes containing putative GC-rich Sp1-binding site in their promoters. A better understanding of the mechanisms underlying Sp1 transcription factor (TF) regulation and functions in OC tumorigenesis could help identify novel prognostic markers, to target cancer stem cells (CSCs) by following cellular reprogramming and enable the development of novel therapies for future generations. In this review, we address the structure, function, and biology of Sp1 in normal and cancer cells, underpinning the involvement of Sp1 in OC tumorigenesis. In addition, we have highlighted the influence of Sp1 TF in cellular reprogramming of iPSCs and how it plays a role in controlling CSCs. This review highlights the drugs targeting Sp1 and their action on cancer cells. In conclusion, we predict that research in this direction will be highly beneficial for OC treatment, and chemotherapeutic drugs targeting Sp1 will emerge as a promising therapy for OC.

Betulinic acid shows anticancer activity against equine melanoma cells and permeates isolated equine skin in vitro

BACKGROUND

Equine malignant melanoma (EMM) is a frequently occurring dermoepidermal tumor in grey horses. Currently available therapies are either challenging or inefficient. Betulinic acid (BA), a naturally occurring triterpenoid, is a promising compound for cancer treatment. To evaluate the potential of BA as a topical therapy for EMM, its anticancer effects on primary equine melanoma cells and dermal fibroblasts and its percutaneous permeation through isolated equine skin were assessed in vitro.

RESULTS

BA showed antiproliferative and cytotoxic effects on both primary equine melanoma cells and fibroblasts in a time- and dose-dependent manner. The lowest half-maximal inhibitory concentrations were obtained 96 h after the beginning of drug exposure (12.7 μmol/L and 23.6 μmol/L for melanoma cells eRGO1 and MelDuWi, respectively, in cytotoxicity assay). High concentrations of the compound were reached in the required skin layers in vitro.

CONCLUSION

BA is a promising substance for topical EMM treatment. Further clinical studies in horses are necessary to assess safety and antitumoral effects in vivo.

Long Non-Coding RNA Plasmacytoma Variant Translocation 1 (PVT1) Enhances Proliferation, Migration, and Epithelial-Mesenchymal Transition (EMT) of Pituitary Adenoma Cells by Activating β-Catenin, c-Myc, and Cyclin D1 Expression

BACKGROUND As a kind of benign tumor, pituitary adenomas have attracted increasing attention from researchers. The plasmacytoma variant translocation 1 (PVT1) is a molecule in the lncRNA family protein that has been proven to play critical roles in many cancers; however, no study has explored the special biological roles of PVT1 in pituitary adenoma. MATERIAL AND METHODS The qRT-PCR assay was conducted to evaluate PVT1 expressions in various cell lines and tissues. Loss of function assays were carried out to detect the influence of silenced PVT1 on the proliferation, migration, and epithelial-mesenchymal transition (EMT) of pituitary adenoma cells. Western blotting was used to identify correlation between ß-catenin and PVT1. RESULTS The PVT1 expressions were significantly enhanced in tissues of pituitary adenoma and cancer cells. Cell migration and proliferation were inhibited when the PVT1 gene was knocked down. Knockdown of PVT1 repressed the migration and EMT of pituitary adenoma cells. The PVT1 downregulation obviously blocked Wnt/ß-catenin signaling pathway activity. PVT1 aggravated progression of pituitary adenoma through initiating the Wnt/ß-catenin signaling pathway. CONCLUSIONS PVT1 exerts an oncogenic role through activating Wnt/ß-catenin signaling in pituitary adenoma cells. The present results may provide a potential therapeutic target or approach for treating pituitary adenomas.

Dietary Compounds for Targeting Prostate Cancer

Prostate cancer is the third most common cancer worldwide, and the burden of the disease is increased. Although several chemotherapies have been used, concerns about the side effects have been raised, and development of alternative therapy is inevitable. The purpose of this study is to prove the efficacy of dietary substances as a source of anti-tumor drugs by identifying their carcinostatic activities in specific pathological mechanisms. According to numerous studies, dietary substances were effective through following five mechanisms; apoptosis, anti-angiogenesis, anti-metastasis, microRNA (miRNA) regulation, and anti-multi-drug-resistance (MDR). About seventy dietary substances showed the anti-prostate cancer activities. Most of the substances induced the apoptosis, especially acting on the mechanism of caspase and poly adenosine diphosphate ribose polymerase (PARP) cleavage. These findings support that dietary compounds have potential to be used as anticancer agents as both food supplements and direct clinical drugs.

Betulinic Acid Suppresses Ovarian Cancer Cell Proliferation through Induction of Apoptosis

Ovarian cancer is one of the leading causes of cancer deaths worldwide in women, and the most malignant cancer among the different gynecological cancers. In this study, we explored potentially anticancer compounds from Cornus walteri (Cornaceae), the MeOH extract of which has been reported to show considerable cytotoxicity against several cancer cell lines. Phytochemical investigations of the MeOH extract of the stem and stem bark of C. walteri by extensive application of chromatographic techniques resulted in the isolation of 14 compounds (1-14). The isolated compounds were evaluated for inhibitory effects on the viability of A2780 human ovarian carcinoma cells and the underlying molecular mechanisms were investigated. An 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was employed to assess the anticancer effects of compounds 1-14 on A2780 cells, which showed that compound 11 (betulinic acid) reduced the viability of these cells in a concentration-dependent manner and had an half maximal (50%) inhibitory concentration (IC50) of 44.47 μM at 24 h. Nuclear staining and image-based cytometric assay were carried out to detect the induction of apoptosis by betulinic acid. Betulinic acid significantly increased the condensation of nuclei and the percentage of apoptotic cells in a concentration-dependent manner in A2780 cells. Western blot analysis was performed to investigate the underlying mechanism of apoptosis. The results indicated that the expression levels of cleaved caspase-8, -3, -9, and Bax were increased in A2780 cells treated with betulinic acid, whereas those of Bcl-2 were decreased. Thus, we provide the experimental evidence that betulinic acid can induce apoptosis in A2780 cells through both mitochondria-dependent and -independent pathways and suggest the potential use of betulinic acid in the development of novel chemotherapeutics for ovarian cancer therapy.

Betulin and its derivatives as novel compounds with different pharmacological effects

Betulin (B) and Betulinic acid (BA) are natural pentacyclic lupane-structure triterpenoids which possess a wide range of pharmacological activities. Recent evidence indicates that B and BA have several properties useful for the treatment of metabolic disorders, infectious diseases, cardiovascular disorders, and neurological disorders. In the current review, we discuss B and BA structures and derivatives and then comprehensively explain their pharmacological effects in relation to various diseases. We also explain antiviral, antibacterial and anti-cancer effects of B and BA. Finally, we discuss the delivery methods, in which these compounds most effectively target different systems.

Betulinic acid induces apoptosis and inhibits metastasis of human colorectal cancer cells in vitro and in vivo

Betulinic acid (BA) is a pentacyclic triterpenoids extracted from birch with a wide range of biological properties. Recent studies have shown that BA has significant cytotoxicity to various types of human cancer cells, and shows potential in cancer treatment. However, the efficacy of BA on human colorectal cancer tumor cells is still unclear. The purpose of our study was to evaluate the anti-cancer activity of BA in human colorectal cancer cells in vitro and in vivo to investigate the possible mechanism. In this experiment, we found that BA inhibited colorectal cancer cell lines in vitro with a time-dependent and dose-dependent manner. Moreover, BA could induce cell apoptosis by upregulating expression of Bax and cleaved caspase-3 and downregulating protein of Bcl-2. BA could increase the production of reactive oxygen species and reduce mitochondrial membrane potential of cancer cell, suggesting that BA induced cancer cells apoptosis by mitochondrial mediated pathways. Furthermore, BA significantly inhibited the migration and invasion of colorectal cancer cells, reduced the expression of matrix metalloproteinase (MMPs) and increased the expression of MMPs inhibitor (TIMP-2). In addition, the growth of tumor was significantly suppressed by intraperitoneal administration of 20 mg/kg/day of BA in a xenograft tumor mouse model of HCT-116. Histopathological and immunohistochemical analysis showed that MMP-2+ cells and Ki-67+ cells were reduced and cleaved caspase-3+ cells were increased in tumor tissues of mice after BA administration. The results showed that BA not only promoted the apoptosis of colorectal cancer cells, but also inhibited the metastasis of cancer cells. Our results suggest that BA can be a potential natural drug to inhibit the growth and metastasis of colorectal cancer.

Reactive Oxygen Species (ROS)-Inducing Triterpenoid Inhibits Rhabdomyosarcoma Cell and Tumor Growth through Targeting Sp Transcription Factors

Methyl 2-trifluoromethyl-3,11-dioxo-18β-olean-1,12-dien-3-oate (CF3DODA-Me) is derived synthetically from glycyrrhetinic acid, a major component of licorice, and this compound induced reactive oxygen species (ROS) in RD and Rh30 rhabdomyosarcoma (RMS) cells. CF3DODA-Me also inhibited growth and invasion and induced apoptosis in RMS cells, and these responses were attenuated after cotreatment with the antioxidant glutathione, demonstrating the effective anticancer activity of ROS in RMS. CF3DODA-Me also downregulated expression of specificity protein (Sp) transcription factors Sp1, Sp3, and Sp4 and prooncogenic Sp-regulated genes including PAX3-FOXO1 (in Rh30 cells). The mechanism of CF3DODA-Me-induced Sp-downregulation involved ROS-dependent repression of c-Myc and cMyc-regulated miR-27a and miR-17/20a, and this resulted in induction of the miRNA-regulated Sp repressors ZBTB4, ZBTB10, and ZBTB34. The cell and tumor growth effects of CF3DODA-Me further emphasize the sensitivity of RMS cells to ROS inducers and their potential clinical applications for treating this deadly disease. IMPLICATIONS: CF3DODA-Me and HDAC inhibitors that induce ROS-dependent Sp downregulation could be developed for clinical applications in treating rhabdomyosarcoma.

Baicalin induces apoptosis in SW480 cells through downregulation of the SP1 transcription factor

Colorectal cancer occurs throughout the world but is most common in developed countries. Cancer progression is believed to be driven by genetic mutations in this complex condition. Risk factors for developing colorectal cancer include a genetic family history, long-term ulcerative colitis, and colonic polyps. The use of baicalin has been reported to be clinically efficacious against colon tumors in Asian countries despite an unclear mechanism of action. Several cancers have been found to be biologically dependent on the specificity protein 1 (sp1) transcription factor family. We hypothesized that baicalin may exert its chemotherapeutic effects by sp1 downregulation. Using the SW480 human colorectal cancer cell line, we investigated the physiological properties of baicalin. Our experiments were designed toward clarifying three goals: (a) to determine the mRNA expression profile of transcription factors in colorectal cancer patients using a microarray-based analysis; (b) to determine the effects of baicalin on the sp1 transcription factor with western blotting and reporter cell assays; and (c) to contrast the effects of mithramycin-A (an sp1 transcription factor inhibitor) and baicalin using western blotting and reporter cell assays. Both baicalin and mithramycin-A downregulated sp1 expression, attenuated SW480 cell proliferation, and increased cell apoptosis. Baicalin inhibited sp1 expression and led to SW480 apoptosis, thus clarifying the effect of this traditional Chinese medicine compound in the treatment of colon cancer.

Dietary phytochemicals in colorectal cancer prevention and treatment: A focus on the molecular mechanisms involved

Worldwide, colorectal cancer (CRC) remains a major cancer type and leading cause of death. Unfortunately, current medical treatments are not sufficient due to lack of effective therapy, adverse side effects, chemoresistance and disease recurrence. In recent decades, epidemiologic observations have highlighted the association between the ingestion of several phytochemical-enriched foods and nutrients and the lower risk of CRC. According to preclinical studies, dietary phytochemicals exert chemopreventive effects on CRC by regulating different markers and signaling pathways; additionally, the gut microbiota plays a role as vital effector in CRC onset and progression, therefore, any dietary alterations in it may affect CRC occurrence. A high number of studies have displayed a key role of growth factors and their signaling pathways in the pathogenesis of CRC. Indeed, the efficiency of dietary phytochemicals to modulate carcinogenic processes through the alteration of different molecular targets, such as Wnt/β-catenin, PI3K/Akt/mTOR, MAPK (p38, JNK and Erk1/2), EGFR/Kras/Braf, TGF-β/Smad2/3, STAT1-STAT3, NF-кB, Nrf2 and cyclin-CDK complexes, has been proven, whereby many of these targets also represent the backbone of modern drug discovery programs. Furthermore, epigenetic analysis showed modified or reversed aberrant epigenetic changes exerted by dietary phytochemicals that led to possible CRC prevention or treatment. Therefore, our aim is to discuss the effects of some common dietary phytochemicals that might be useful in CRC as preventive or therapeutic agents. This review will provide new guidance for research, in order to identify the most studied phytochemicals, their occurrence in foods and to evaluate the therapeutic potential of dietary phytochemicals for the prevention or treatment of CRC by targeting several genes and signaling pathways, as well as epigenetic modifications. In addition, the results obtained by recent investigations aimed at improving the production of these phytochemicals in genetically modified plants have been reported. Overall, clinical data on phytochemicals against CRC are still not sufficient and therefore the preventive impacts of dietary phytochemicals on CRC development deserve further research so as to provide additional insights for human prospective studies.

Effects and mechanisms of betulinic acid on improving EGFR TKI-resistance of lung cancer cells

Epidermal growth factor receptor (EGFR) mutations have been identified in approximately 55% of lung cancer patients in Taiwan. Gefitinib (Iressa) and Erlotinib (Tarceva) are the first-generation targeting drugs to patients with EGFR gene mutants a work by inhibiting tyrosine kinase activity. However, resistance in EGFR-mutated patients to first-generation tyrosine kinase inhibitor (TKI) therapy after 8-11 months of treatment has occurred. Betulinic acid (BetA) is a pentacyclic triterpenoid natural product derived from widespread plants. BetA has been reported to have a cytotoxic effect in several cancers. The purpose of this study is to investigate the effects and mechanisms of BetA on dampening EGFR TKI-resistance of lung cancer cells. Our study has demonstrated by MTT assay that combining BetA and an EGFR TKI increased the cytotoxicity against EGFR TKI-resistance lung cancer cells. Based on flow cytometry, combination treatments of BetA with an EGFR TKI enhanced Sub-G1 accumulation, induced apoptosis and induced mitochondrial membrane potential loss. Using western blotting, BetA and EGFR TKI combined treatments inhibited cell cycle related protein and triggered apoptosis- and autophagy- related protein expression. Taken together, our data suggests that a target therapy combining BetA with an EGFR TKI improves drug efficacy in EGFR TKI-resistant lung cancer cells.

Betulinic acid inhibits stemness and EMT of pancreatic cancer cells via activation of AMPK signaling

Cancer stem cells (CSCs), which are found in various types of human cancer, including pancreatic cancer, possess elevated metastatic potential, lead to tumor recurrence and cause chemoradiotherapy resistance. Alterations in cellular bioenergetics through the regulation of 5′ adenosine monophosphate-activated protein kinase (AMPK) signaling may be a prerequisite to stemness. Betulinic acid (BA) is a well-known bioactive compound with antiretroviral and anti-inflammatory potential, which has been reported to exert anticancer effects on various types of cancer, including pancreatic cancer. The present study aimed to investigate whether BA could inhibit pancreatic CSCs via regulation of AMPK signaling. The proliferation of pancreatic cancer cells was examined by MTT and colony formation assays. The migratory and invasive abilities of pancreatic cancer cells were assessed using wound-scratch and Transwell invasion assays. In addition, the expression levels of candidate genes were measured by reverse transcription-quantitative polymerase chain reaction and western blotting. The results revealed that BA inhibited the proliferation and tumorsphere formation of pancreatic cancer cells, suppressed epithelial-mesenchymal transition (EMT), migration and invasion, and reduced the expression of three pluripotency factors [SRY-box 2 (Sox2), octamer-binding protein 4 (Oct4) and Nanog]. Furthermore, immunohistochemical analysis confirmed that there was a significant inverse association between the expression levels of phosphorylated (P)-AMPK and Sox2 in pancreatic cancer, and it was revealed that BA may activate AMPK signaling. Notably, knockdown of AMPK reversed the suppressive effects of BA on EMT and stemness of pancreatic cancer cells. In addition, BA reversed the effects of gemcitabine on stemness and enhanced the sensitivity of pancreatic cancer cells to gemcitabine. Collectively, these results indicated that BA may effectively inhibit pluripotency factor expression (Sox2, Oct4 and Nanog), EMT and the stem-like phenotype of pancreatic cancer cells via activating AMPK signaling. Therefore, BA may be considered an attractive therapeutic candidate and an effective inhibitor of the stem-like phenotype in pancreatic cancer cells. Further investigation into the development of BA as an anticancer drug is warranted.