Ursolic acid inhibits the proliferation of human ovarian cancer stem-like cells through epithelial-mesenchymal transition

The latest research progress: Active components of Traditional Chinese medicine as promising candidates for ovarian cancer therapy

ETHNOPHARMACOLOGICAL RELEVANCE

Ovarian cancer ranks the first in the mortality of gynecological tumors. Because there are no obvious symptoms in the early stage of ovarian cancer, most patients are in the advanced stage of the disease at the time of diagnosis. The incidence of ovarian cancer is increasing year by year, and the incidence of ovarian cancer has a trend of younger age. In recent years. Traditional Chinese medicine (TCM) has a significant impact on improving the quality of life of cancer patients, reducing drug toxicity, preventing metastasis and recurrence, enhancing the efficacy of radiotherapy and chemotherapy, and prolonging survival time, so patients have benefited a lot.

AIM OF THE STUDY

This review summarizes the mechanisms and molecular pathways through which active ingredients of TCM act in ovarian cancer. It explores the advantages of TCM in treating ovarian cancer. This review provides theoretical support for the use of TCM in the treatment of ovarian cancer, offering new perspectives for its clinical prevention and treatment.

MATERIALS AND METHODS

This review conducted a literature search on PubMed, Web of Science, Wanfang Database, and China National Knowledge Infrastructure (CNKI) for relevant studies on TCM active ingredients in preventing ovarian cancer. The search terms included "ovarian cancer" combined with "Chinese herbal medicine," "Herbal medicine," "Traditional Chinese medicine," and "Active ingredients of Chinese medicine". Based on existing experimental and clinical research, the paper systematically summarized and analyzed the mechanisms of TCM in treating ovarian cancer.

RESULTS

Active ingredients of TCM inhibit the occurrence and development of ovarian cancer through inducing tumor cell apoptosis, inhibiting tumor cell proliferation, suppressing tumor cell migration and invasion, inducing tumor cell autophagy, promoting epithelial-mesenchymal transition, and enhancing the efficacy of radiotherapy and chemotherapy drugs. Chinese medicine provides a comprehensive treatment option for ovarian cancer patients, synergizing with radiotherapy and chemotherapy drugs to enhance treatment effectiveness and introduce new hope and possibilities in clinical therapy.

CONCLUSIONS

Active ingredients of TCM can inhibit the occurrence and development of ovarian cancer, but further clinical research is needed to support their application.

Multifunctional metal-coordinated Co-assembled carrier-free nanoplatform based on dual-drugs for ferroptosis-mediated cocktail therapy of hepatocellular carcinoma growth and metastasis

The heterogeneity of hepatocellular carcinoma (HCC) and the complexity of the tumor microenvironment (TME) pose challenges to efficient drug delivery and the antitumor efficacy of combined or synergistic therapies. Herein, a metal-coordinated carrier-free nanodrug (named as USFe3+ LA NPs) was developed for ferroptosis-mediated multimodal synergistic anti-HCC. Natural product ursolic acid (UA) was incorporated to enhance the sensitivity of tumor cells to sorafenib (SRF). Surface decoration of cell penetration peptide and epithelial cell adhesion molecule aptamer facilitated the uptake of USFe3+ LA NPs by HepG2 cells. Meanwhile, Fe3+ ions could react with intracellular hydrogen peroxide, generating toxic hydroxyl radical (·OH) for chemodynamical therapy (CDT) and amplified ferroptosis by cystine/glutamate antiporter system (System Xc-), which promoted the consumption of glutathione (GSH) and inhibited the expression of glutathione peroxidase 4 (GPX4). Notably, these all-in-one nanodrugs could inhibit tumor metastasis and induced immunogenic cell death (ICD). Last but not least, the nanodrugs demonstrated favorable biocompatibility, augmenting the immune response against the programmed death-ligand 1 (PD-L1) by increasing cytotoxic T cell infiltration. In vivo studies revealed significant suppression of tumor growth and distant metastasis. Overall, our work introduced a novel strategy for applications of metal-coordinated co-assembled carrier-free nano-delivery system in HCC combination therapy, especially in the realms of cancer metastasis prevention and immunotherapy.

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

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

Mechanism of epithelial-mesenchymal transition in cancer and its regulation by natural compounds

Epithelial-mesenchymal transition (EMT) is a complex process with a primordial role in cellular transformation whereby an epithelial cell transforms and acquires a mesenchymal phenotype. This transformation plays a pivotal role in tumor progression and self-renewal, and exacerbates resistance to apoptosis and chemotherapy. EMT can be initiated and promoted by deregulated oncogenic signaling pathways, hypoxia, and cells in the tumor microenvironment, resulting in a loss-of-epithelial cell polarity, cell-cell adhesion, and enhanced invasive/migratory properties. Numerous transcriptional regulators, such as Snail, Slug, Twist, and ZEB1/ZEB2 induce EMT through the downregulation of epithelial markers and gain-of-expression of the mesenchymal markers. Additionally, signaling cascades such as Wnt/β-catenin, Notch, Sonic hedgehog, nuclear factor kappa B, receptor tyrosine kinases, PI3K/AKT/mTOR, Hippo, and transforming growth factor-β pathways regulate EMT whereas they are often deregulated in cancers leading to aberrant EMT. Furthermore, noncoding RNAs, tumor-derived exosomes, and epigenetic alterations are also involved in the modulation of EMT. Therefore, the regulation of EMT is a vital strategy to control the aggressive metastatic characteristics of tumor cells. Despite the vast amount of preclinical data on EMT in cancer progression, there is a lack of clinical translation at the therapeutic level. In this review, we have discussed thoroughly the role of the aforementioned transcription factors, noncoding RNAs (microRNAs, long noncoding RNA, circular RNA), signaling pathways, epigenetic modifications, and tumor-derived exosomes in the regulation of EMT in cancers. We have also emphasized the contribution of EMT to drug resistance and possible therapeutic interventions using plant-derived natural products, their semi-synthetic derivatives, and nano-formulations that are described as promising EMT blockers.

Ursolic and oleanolic acids in combination therapy inhibit migration of colon cancer cells through down-regulation of the uPA/uPAR-dependent MMPs pathway

BACKGROUND

Colorectal cancer is one the most lethal cancers worldwide. Since chemotherapy is burdened with harmful effects, agents capable of enhancing the chemotherapeutic effect are being sought. Ursolic acid (UA) and oleanolic acid (OA) were analyzed for such properties. The aim of the study was to evaluate the ability of UA and OA administered individually and in combination with each other and/or a cytostatic drug camptothecin-11 (CPT-11) to limit the viability and migration of colorectal cancer cells.

MATERIALS AND METHODS

The cytotoxic effect of UA, OA and CPT-11 and impact on normal and cancer cell migration rate were assessed. Furthermore, the effect on factors crucial in cancer metastasis: MMP-2 and -9, uPA/uPAR, and E-cadherin were assessed with ELISA, Western Blotting and immunofluorescence assays. Statistical analysis was performed with One-Way Anova with Dunnett's test.

RESULTS

The studied compounds exhibited the most favorable properties, i.e. they reduced the viability and migration of cancer cells. Furthermore, the secretion, activity, and cellular level of cancer MMP-2 and -9 were decreased, as a result of uPA/uPAR down-regulation. The agents also increased the level of cellular E-cadherin. The effect of the studied agents on normal cells was milder.

CONCLUSIONS

The compounds exhibited stronger activity when administered in combination and, combined with CPT-11, enhanced anti-tumorigenic activity of the drug. The migration-limiting activity was based on down-regulation of the uPA/uPAR-dependent MMP pathway. Moreover, UA and OA exhibited a protective effect towards normal cells.

Antitumor Effects of Ursolic Acid through Mediating the Inhibition of STAT3/PD-L1 Signaling in Non-Small Cell Lung Cancer Cells

Targeted therapy based on natural compounds is one of the best approaches against non-small cell lung cancer. Ursolic acid (UA), a pentacyclic triterpenoid derived from medicinal herbs, has anticancer activity. Studies on the molecular mechanism underlying UA’s anticancer activity are ongoing. Here, we demonstrated UA’s anticancer activity and the underlying signaling mechanisms. We used Western blotting and real-time quantitative polymerase chain reaction for molecular signaling analysis. We also used in vitro angiogenesis, wound healing, and invasion assays to study UA’s anticancer activity. In addition, we used tumorsphere formation and chromatin immunoprecipitation assays for binding studies. The results showed that UA inhibited the proliferation of A549 and H460 cells in a concentration-dependent manner. UA exerted anticancer effects by inducing G0/G1 cell cycle arrest and apoptosis. It also inhibited tumor angiogenesis, migration, invasion, and tumorsphere formation. The molecular mechanism underlying UA activity involves UA’s binding to epidermal growth factor receptor (EGFR), reducing the level of phospho-EGFR, and thus inhibiting the downstream JAK2/STAT3 pathway. Furthermore, UA reduced the expressions of vascular endothelial growth factor (VEGF), metalloproteinases (MMPs) and programmed death ligand-1 (PD-L1), as well as the formation of STAT3/MMP2 and STAT3/PD-L1 complexes. Altogether, UA exhibits anticancer activities by inhibiting MMP2 and PD-L1 expression through EGFR/JAK2/STAT3 signaling.

Screening of metabolic modulators identifies new strategies to target metabolic reprogramming in melanoma

The prognosis of metastatic melanoma remains poor due to de novo or acquired resistance to immune and targeted therapies. Previous studies have shown that melanoma cells have perturbed metabolism and that cellular metabolic pathways represent potential therapeutic targets. To support the discovery of new drug candidates for melanoma, we examined 180 metabolic modulators, including phytochemicals and anti-diabetic compounds, for their growth-inhibitory activities against melanoma cells, alone and in combination with the BRAF inhibitor vemurafenib. Two positive hits from this screen, 4-methylumbelliferone (4-MU) and ursolic acid (UA), were subjected to validation and further characterization. Metabolic analysis showed that 4-MU affected cellular metabolism through inhibition of glycolysis and enhanced the effect of vemurafenib to reduce the growth of melanoma cells. In contrast, UA reduced mitochondrial respiration, accompanied by an increase in the glycolytic rate. This metabolic switch potentiated the growth-inhibitory effect of the pyruvate dehydrogenase kinase inhibitor dichloroacetate. Both drug combinations led to increased production of reactive oxygen species, suggesting the involvement of oxidative stress in the cellular response. These results support the potential use of metabolic modulators for combination therapies in cancer and may encourage preclinical validation and clinical testing of such treatment strategies in patients with metastatic melanoma.

Phytochemicals in Gynecological Cancer Prevention

Gynecological cancer confers an enormous burden among women worldwide. Accumulating evidence points to the role of phytochemicals in preventing cervical, endometrial, and ovarian cancer. Experimental studies emphasize the chemopreventive and therapeutic potential of plant-derived substances by inhibiting the early stages of carcinogenesis or improving the efficacy of traditional chemotherapeutic agents. Moreover, a number of epidemiological studies have investigated associations between a plant-based diet and cancer risk. This literature review summarizes the current knowledge on the phytochemicals with proven antitumor activity, emphasizing their effectiveness and mechanism of action in gynecological cancer.

Untargeted Metabolomic Characterization of Ovarian Tumors

Simple Summary

This study utilized untargeted metabolomic techniques to detect urine and plasma metabolites. Using support vector machine algorithm, three models for ovarian tumors diagnosis, benign-malignant distinguishing, early diagnosis and borderline-malignant distinguishing were developed. These models have good classification performance and provided a novel insight for non-invasive diagnosis of ovarian cancer.

Abstract

Diagnosis of ovarian cancer is difficult due to the lack of clinical symptoms and effective screening algorithms. In this study, we aim to develop models for ovarian cancer diagnosis by detecting metabolites in urine and plasma samples. Ultra-high-performance liquid chromatography and quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) in positive ion mode was used for metabolome quantification in 235 urine samples and 331 plasma samples. Then, Urine and plasma metabolomic profiles were analyzed by univariate and multivariate statistics. Four groups of samples: normal control, benign, borderline and malignant ovarian tumors were enrolled in this study. A total of 1330 features and 1302 features were detected from urine and plasma samples respectively. Based on two urine putative metabolites, five plasma putative metabolites and five urine putative metabolites, three models for distinguishing normal-ovarian tumors, benign-malignant (borderline + malignant) and borderline-malignant ovarian tumors were developed respectively. The AUC (Area Under Curve) values were 0.987, 0876 and 0.943 in discovery set and 0.984, 0.896 and 0.836 in validation set for three models. Specially, the diagnostic model based on 5 plasma putative metabolites had better early-stage diagnosis performance than CA125 alone. The AUC values of the model were 0.847 and 0.988 in discovery and validation set respectively. Our results showed that normal and ovarian tumors have unique metabolic signature in urine and plasma samples, which shed light on the ovarian cancer diagnosis and classification.

Synthesis and antitumor activity evaluation of ursolic acid derivatives

Eighteen uronic acid derivatives were designed and synthesized, and the cytotoxicities in vitro of two cancer cell lines (BEL7402 and SGC7901) were evaluated by MTT assay. The results showed that the inhibitory rate of the compounds on both cell lines was significantly higher than the parent compound. The IC50 of compounds II4, II6, III4, and III6 are comparable or stronger than the positive control drug, the interactions between compounds II4, II6, III4, III6, and NF-κB were also studied by docking simulations.

Triterpenoids

This review covers newly isolated triterpenoids that have been reported during 2015.

Ursolic Acid Attenuates TGF-β1-Induced Epithelial-Mesenchymal Transition in NSCLC by Targeting Integrin αVβ5/MMPs Signaling

Transforming growth factor-β1 (TGF-β1)-induced epithelial-mesenchymal transition (EMT) of non-small cell lung cancer (NSCLC) may contribute to tumor metastasis. TGF-β1-induced EMT in H1975 cells (a human NSCLC cell line) resulted in the adoption of mesenchymal responses that were predominantly mediated via the TGF-β1-integrin signaling pathway. Ursolic acid has been previously reported to inhibit tumor growth and metastasis in several cancers. However, whether ursolic acid can attenuate TGF-β1-induced EMT in H1975 cells and its underlying mechanisms remain unknown. In this study, ursolic acid significantly attenuated the TGF-β1-induced decrease in E-cadherin level and elevated the level of N-cadherin. Furthermore, ursolic acid inhibited the mesenchymal-like responses in H1975 cells, including cell migration, invasion, and activity of matrix metallopeptidase (MMP)-2 and -9. Finally, our new findings provided evidence that ursolic acid could inhibit EMT in NSCLC through TGF-β1 signaling pathway-mediated integrin αVβ5 expression, and this might be the potential mechanism of resveratrol on the inhibition of invasion and metastases in NSCLC. We conclude that ursolic acid attenuated TGF-β1-induced EMT in H1975 cells and thus might be a promising therapeutic agent for treating NSCLC.

Correction to: In Vitro-In Vivo Dose Response of Ursolic Acid, Sulforaphane, PEITC, and Curcumin in Cancer Prevention

The citation of the author name "Ah-Ng Tony Kong" in PubMed is not the author's preference. Instead of "Kong AT", the author prefers "Kong AN".

Ursolic acid activates the apoptosis of prostate cancer via ROCK/PTEN mediated mitochondrial translocation of cofilin-1

Ursolic acid has various pharmacological activities, and can reduce blood fat as well as having antihepatic, antitumoral, anti-inflammatory and antiviral properties. However, the pro-apoptotic mechanism by which ursolic acid influences human prostate cancer requires additional study. The aim of the present study was to assess whether ursolic acid activates the apoptosis of prostate cancer and to investigate the mechanism by which the Rho-associated protein kinase 1 (ROCK1)/phosphatase and tensin homolog (PTEN) signaling pathway performs a role in ursolic acid-mediated cofilin-1 to induce apoptosis in human prostate cancer. Firstly, the present study determined the pro-apoptotic mechanism by which ursolic acid influences the cell proliferation and apoptosis of human prostate LNCaP cancer cells. Caspase-3/9 activities and ROCK1, PTEN, Cofilin-1 and cytochrome c protein expression levels were also analyzed. In the present study, it is reported that the pro-apoptotic mechanism of ursolic acid potently suppressed the cell proliferation of human prostate LNCaP cancer cells. The present study revealed that the mediation of ROCK1/PTEN-cofilin-1/cytochrome c protein expression activates caspase-3/9 activities which subsequently induced the apoptosis of human prostate cancer cells. In conclusion, these findings demonstrated that ursolic acid activates the apoptosis of prostate cancer via ROCK/PTEN mediated cofilin-1/cytochrome c which mediated caspase-3/9 activities.

In Vitro-In Vivo Dose Response of Ursolic Acid, Sulforaphane, PEITC, and Curcumin in Cancer Prevention

According to the National Center of Health Statistics, cancer was the culprit of nearly 600,000 deaths in 2016 in the USA. It is by far one of the most heterogeneous diseases to treat. Treatment for metastasized cancers remains a challenge despite modern diagnostics and treatment regimens. For this reason, alternative approaches are needed. Chemoprevention using dietary phytochemicals such as triterpenoids, isothiocyanates, and curcumin in the prevention of initiation and/or progression of cancer poses a promising alternative strategy. However, significant challenges exist in the extrapolation of in vitro cell culture data to in vivo efficacy in animal models and to humans. In this review, the dose at which these phytochemicals elicit a response in vitro and in vivo of a multitude of cellular signaling pathways will be reviewed highlighting Nrf2-mediated antioxidative stress, anti-inflammation, epigenetics, cytoprotection, differentiation, and growth inhibition. The in vitro-in vivo dose response of phytochemicals can vary due, in part, to the cell line/animal model used, the assay system of the biomarker used for the readout, chemical structure of the functional analog of the phytochemical, and the source of compounds used for the treatment study. While the dose response varies across different experimental designs, the chemopreventive efficacy appears to remain and demonstrate the therapeutic potential of triterpenoids, isothiocyanates, and curcumin in cancer prevention and in health in general.

Review on Research about Traditional Chinese Medicine in Cancer Stem Cell

Cancer stem cells (CSCs) are small subpopulations of neoplastic cells within a tumor, which have self-renewal and differentiation abilities and could generate new tumors with few cells. Researches have showed that CSCs are considered the most likely reason for cancer recurrence and metastasis. Accumulating evidences have showed that traditional Chinese medicine (TCM) has significant effect on CSCs. It could inhibit the proliferation, self-renew, and multidifferentiation of CSCs. We aimed to summarize the theories of CSCs in TCM, the inhibitory effect, and the pathway on CSCs of TCM. This review will provide potential new strategies and alternative perspectives for CSCs treatments and basic research into complementary and alternative medicine.

Ursolic acid inhibits breast cancer growth by inhibiting proliferation, inducing autophagy and apoptosis, and suppressing inflammatory responses via the PI3K/AKT and NF-κB signaling pathways in vitro

Breast cancer, which is the second leading cause of cancer-associated mortality in women worldwide, develops from breast tissue. Chemotherapy is the most commonly used therapy to treat breast cancer. However, a number of natural plant-derived products have been suggested as alternative therapies to treat different types of cancer, such as breast cancer. The aim of the present study was to determine the anti-tumor effects of ursolic acid and its effect on apoptosis and inflammation in breast cancer cells. The anti-cancer effects of ursolic acid were evaluated in vitro using flow cytometry, western blotting and reverse transcription-quantitative polymerase chain reaction. The results suggest that ursolic acid inhibits the viability of breast cancer cells by inducing autophagy and apoptosis without inducing cell death. Cellular migration assays demonstrated that ursolic acid was able to suppress the invasive ability of breast cancer cells (P<0.05). In addition, the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway was downregulated following ursolic acid administration (P<0.05), leading to an upregulation of glycogen synthase kinase activity (P<0.05) and downregulation of B-cell lymphoma 2 (P<0.05), subsequently causing autophagy and apoptosis via cyclin-D1 inhibition and caspase-3 stimulation (P<0.05). Furthermore, the inflammatory response of breast cancer cells was assessed by measuring levels of nuclear factor (NF)-κB. Ursolic acid was found to downregulate NF-κB in breast cancer cells, thus inhibiting inflammation and preventing the progression of breast cancer (P<0.05). To the best of our knowledge, the present study is the first to assess the effect of ursolic acid on breast cancer cells through PI3K/AKT-regulated GSK and caspase-3 accompanied by NF-κB signaling pathways. The results of the present study regarding the potential underlying molecular mechanisms of ursolic acid may be used to develop novel therapeutic strategies for breast cancer treatment.

Radioprotective effect of ursolic acid in radiation-induced impairment of neurogenesis, learning and memory in adolescent BALB/c mouse

The effect of acute irradiation with 5Gy or fractionated exposure with 0.5Gy continuously for 10days (a total dose of 5Gy) was evaluated in an immature BALB/c mouse model. Radioprotective effect of ursolic acid (at 25mg/kg/daily administered 1h after acute or each of fractionated irradiations, and continuously for 30days) was also investigated. We found that both acute and fractionated irradiation at a total dose of 5Gy did not induce any mortality within 30days after exposure to postnatal day 26 (P26) BALB/c mice, but reduced animal weigh gain in the first few weeks. At 90days after irradiation, the weight of animals with acute irradiation was still significantly lower than the control group; no significant difference though was observed for those fractionatedly exposed mice compared to the control group. Behavioral tests indicated that acute irradiation at 5Gy induced deficits in learning and memory in the contextual fear conditioning test. The memory for novel object recognition was also impaired. Similar changes were not observed in mice with fractionated irradiation. Immunohistochemical study demonstrated clearly that acute and fractionated irradiations induced impairment of neurogenesis in the subgranular zone (SGZ) of the dentate gyrus although fractionated exposure induced much lesser loss of newly generated neurons. Ursolic acid administered at 25mg/kg/daily for 30days after irradiation greatly improved acute irradiation-induced deficits in contextual learning and memory and in novel object recognition memory although it exacerbated radiation-induced reduction of neurogenesis in SGZ.

Combined Use of Zoledronic Acid Augments Ursolic Acid-Induced Apoptosis in Human Osteosarcoma Cells through Enhanced Oxidative Stress and Autophagy

Ursolic acid (UA), a naturally occurring pentacyclic triterpene acid found in many medicinal herbs and edible plants, triggers apoptosis in several tumor cell lines but not in human bone cancer cells. Most recently, we have demonstrated that UA exposure reduces the viability of human osteosarcoma MG-63 cells through enhanced oxidative stress and apoptosis. Interestingly, an inhibitor of osteoclast-mediated bone resorption, zoledronic acid (ZOL), also a third-generation nitrogen-containing bisphosphonate, is effective in the treatment of bone metastases in patients with various solid tumors. In this present study, we found that UA combined with ZOL to significantly suppress cell viability, colony formation, and induce apoptosis in two lines of human osteosarcoma cells. The pre-treatment of the antioxidant had reversed the oxidative stress and cell viability inhibition in the combined treatment, indicating that oxidative stress is important in the combined anti-tumor effects. Moreover, we demonstrated that ZOL combined with UA significantly induced autophagy and co-administration of autophagy inhibitor reduces the growth inhibitory effect of combined treatment. Collectively, these data shed light on the pathways involved in the combined effects of ZOL and UA that might serve as a potential therapy against osteosarcoma.

Human endometrial mesenchymal stem cells exhibit intrinsic anti-tumor properties on human epithelial ovarian cancer cells

Epithelial ovarian cancer (EOC) is the most lethal tumor of all gynecologic tumors. There is no curative therapy for EOC thus far. The tumor-homing ability of adult mesenchymal stem cells (MSCs) provide the promising potential to use them as vehicles to transport therapeutic agents to the site of tumor. Meanwhile, studies have showed the intrinsic anti-tumor properties of MSCs against various kinds of cancer, including epithelial ovarian cancer. Human endometrial mesenchymal stem cells (EnSCs) derived from menstrual blood are a novel source for adult MSCs and exert restorative function in some diseases. Whether EnSCs endow innate anti-tumor properties on EOC cells has never been reported. By using tumor-bearing animal model and ex vivo experiments, we found that EnSCs attenuated tumor growth by inducing cell cycle arrest, promoting apoptosis, disturbing mitochondria membrane potential and decreasing pro-angiogenic ability in EOC cells in vitro and/or in vivo. Furthermore, EnSCs decreased AKT phosphorylation and promoted nuclear translocation of Forkhead box O-3a (FoxO3a) in EOC cells. Collectively, our findings elucidated the potential intrinsic anti-tumor properties of EnSCs on EOC cells in vivo and in vitro. This research provides a potential strategy for EnSC-based anti-cancer therapy against epithelial ovarian cancer.

Blockage of epithelial to mesenchymal transition and upregulation of let 7b are critically involved in ursolic acid induced apoptosis in malignant mesothelioma cell

Malignant pleural mesothelioma (MPN), which is caused by asbestos exposure, is one of aggressive lung tumors. In the present study, we elucidated the anti-tumor mechanism of ursolic acid in malignant mesotheliomas. Ursolic acid significantly exerted cytotoxicity in a time and dose dependent manner in H28, H2452 and MSTO-211H mesothelioma cells and inhibited cell proliferation by colony formation assay in a dose-dependent fashion. Also, ursolic acid treatment accumulated the sub-G1 population, attenuated the expression of procapase 9, cyclin D1, pAKT, p-glycogen synthase kinase 3-alpha/beta (pGSK3α/β), β-catenin and nuclear factor kappa-light-chain-enhancer of activated B cells (NFkB) and also cleaved caspase 3 and poly (ADP-ribose) polymerase (PARP) in mesothelioma cells. Furthermore, ursolic acid treatment blocked epithelial and mesenchymal transition (EMT) molecules by activating E-cadherin as an epithelial marker and attenuating Vimentin, and Twist as mesenchymal molecules. Interestingly, miRNA array revealed that 23 miRNAs (>2 folds) including let-7b and miRNA3613-5p, miRNA134 and miRNA196b were significantly upregulated while 33 miRNAs were downregulated in ursolic acid treated H2452 cells. Furthermore, overexpression of let 7b using let-7b mimics enhanced the antitumor effect of ursolic acid to attenuate the expression of procaspases 3, pro-PARP, pAKT, β-catenin and Twist and increase sub-G1 accumulation in H2452 mesothelioma cells. Overall, our findings suggest that ursolic acid induces apoptosis via inhibition of EMT and activation of let7b in mesothelioma cells as a potent chemotherapeutic agent for treatment of malignant mesotheliomas.

A Case of Recurrent Hepatocellular Carcinoma Acquiring Complete Remission of Target Lesion With Treatment With Traditional Chinese Medicine

Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies worldwide. Although surgery is known as the most promising radical treatment, a high recurrent or metastatic rate after surgery has limited its clinical efficacy. Sorafenib, a target agent, has seemed to be the only option for metastatic HCC patients to date, but none of clinical trials showed it could prolong the overall survival (OS) of advanced HCC to 1 year. How to prolong the OS and improve cure rate of HCC patients is still beset with difficulties. This report presents a rare case of recurrent HCC patient with complete regression of target lesion with 2 years of Chinese herbal treatment. A 64-year-old Chinese man with hepatitis B virus–associated chronic hepatitis presented HCC has been clinically diagnosed tumor relapse and omentum metastasis with computed tomography and α-fetoprotein blood test 4 months after surgery. It was decided the patient would receive traditional Chinese medicine treatment because of poor prognosis. After approximately 2 years of treatment, recurrent hepatic tumor and omentum metastasis have been found in complete regression. The patient remains alive over 31 months after relapse.

Ursolic acid inhibits proliferation and reverses drug resistance of ovarian cancer stem cells by downregulating ABCG2 through suppressing the expression of hypoxia-inducible factor-1α in vitro

Hypoxia in tumors is closely related to drug resistance. It has not been verified whether hypoxia-inducible factor-1α (HIF-1α) or ABCG2 is related to hypoxia-induced resistance. Ursolic acid (UA), when used in combination with cisplatin can significantly increase the sensitivity of ovarian cancer stem cells (CSCs) to cisplatin, but the exact mechanism is unknown. The cell growth inhibitory rate of cisplatin under different conditions was evaluated using Cell Counting Kit-8 (CCK-8) in adherence and sphere cells (SKOV3, A2780, and HEY). The expression of HIF-1α and ABCG2 was tested using quantitative PCR, western blotting, and immuno-fluorescence under different culture conditions and treated with UA. Knockdown of HIF-1α by shRNA and LY294002 was used to inhibit the activity of PI3K/Akt pathway. Ovarian CSCs express stemness-related genes and drug resistance significantly higher than normal adherent cells. Under hypoxic conditions, the ovarian CSCs grew faster and were more drug resistant than under normoxia. UA could inhibit proliferation and reverse the drug resistance of ovarian CSC by suppressing ABCG2 and HIF-1α under different culture conditions. HIF-1α inhibitor YC-1 combined with UA suppressed the stemness genes and ABCG2 under hypoxic condition. The PI3K/Akt signaling pathway activation plays an important functional role in UA-induced downregulation of HIF-1α and reduction of ABCG2. UA inhibits the proliferation and reversal of drug resistance in ovarian CSCs by suppressing the expression of downregulation of HIF-1α and ABCG2.

Small putative NANOG, SOX2, and SSEA-4-positive stem cells resembling very small embryonic-like stem cells in sections of ovarian tissue in patients with ovarian cancer

BACKGROUND

In previous studies it has been found that in cell cultures of human adult ovaries there is a population of small stem cells with diameters of 2-4 μm, which are present mainly in the ovarian surface epithelium and are comparable to very small embryonic-like stem cells (VSELs) from bone marrow. These cells are not observed by histopathologists in the ovarian tissue due to their small size and unknown clinical significance. Because these cells express a degree of pluripotency, they might be involved in the manifestation of ovarian cancer. Therefore we studied the ovarian tissue sections in women with borderline ovarian cancer and serous ovarian carcinoma to perhaps identify the small putative stem cells in situ.

METHODS

In 27 women with borderline ovarian cancer and 20 women with high-grade serous ovarian carcinoma the ovarian tissue sections were stained, per standard practice, with eosin and hematoxylin staining and on NANOG, SSEA-4 and SOX2 markers, related to pluripotency, using immunohistochemistry. We focused on the presence and localization of small putative stem cells with diameters of up to 5 μm and with the nuclei spread over nearly the full cell volume.

RESULTS

In ovarian sections of both borderline ovarian cancer and serous ovarian carcinoma patients we were able to identify the presence of small round cells complying with the above criteria. Some of these small cells were NANOG-positive, were located among epithelial cells in the ovarian surface epithelium and as a single cell or groups of cells/clusters in typical "chambers", were found only in the presence of ovarian cancer and not in healthy ovaries and are comparable to those in fetal ovaries. We envision that these small cells could be related to NANOG-positive tumor-like structures and oocyte-like cells in similar "chambers" found in sections of cancerous ovaries, which could support their stemness and pluripotency. Further immunohistochemistry revealed a similar population of SSEA-4 and SOX2-positive cells.

CONCLUSIONS

We may conclude that putative small stem cells expressing markers, related to pluripotency, are present in the ovarian tissue sections of women with borderline ovarian cancer and high-grade serous ovarian carcinoma thus indicating their potential involvement in ovarian cancer.

Natural Products for Chemoprevention of Breast Cancer

Breast cancer is the primary cause of cancer death in women. Although current therapies have shown some promise against breast cancer, there is still no effective cure for the majority of patients in the advanced stages of breast cancer. Development of effective agents to slow, reduce, or reverse the incidence of breast cancer in high-risk women is necessary. Chemoprevention of breast cancer by natural products is advantageous, as these compounds have few side effects and low toxicity compared to synthetic compounds. In the present review, we summarize natural products which exert chemopreventive activities against breast cancer, such as curcumin, sauchinone, lycopene, denbinobin, genipin, capsaicin, and ursolic acid. This review examines the current knowledge about natural compounds and their mechanisms that underlie breast cancer chemopreventive activity both in vitro and in vivo. The present review may provide information on the use of these compounds for the prevention of breast cancer.