Atractylenolide II Induces Apoptosis of Prostate Cancer Cells through Regulation of AR and JAK2/STAT3 Signaling Pathways

Research advances in natural sesquiterpene lactones: overcoming cancer drug resistance through modulation of key signaling pathways

Cancer remains a significant global health challenge, with current chemotherapeutic strategies frequently limited by the emergence of resistance. In this context, natural compounds with the potential to overcome resistance have garnered considerable attention. Among these, sesquiterpene lactones, primarily derived from plants in the Asteraceae family, stand out for their potential anticancer properties. This review specifically focuses on five key signaling pathways: PI3K/Akt/mTOR, NF-κB, Wnt/β-catenin, MAPK/ERK, and STAT3, which play central roles in the mechanisms of cancer resistance. For each of these pathways, we detail their involvement in both cancer development and the emergence of drug resistance. Additionally, we investigate how sesquiterpene lactones modulate these pathways to overcome resistance across diverse cancer types. These insights highlight the potential of sesquiterpene lactones to drive the advancement of novel therapies that can effectively combat both cancer progression and drug resistance.

A pharmacoinformatic approach for studying Atractylodes Lancea DC's anticancer potential and control ROS-mediated apoptosis against prostate cancer cells

Introduction

Prostate cancer (PCa) is a malignancy characterized by abnormal cell proliferation in the prostate gland, a critical component of the male reproductive system. Atractylodes lancea DC. (ALD), a medicinal herb commonly used in traditional Asian medicine, is highly regarded for its antioxidant, antidiabetic, and anticancer properties. Virtual docking stud-ies have identified Atractylenolide II and III as active components of ALD, demonstrating strong binding potential to inhibit androgen receptor (AR) activity, with docking scores of -8.9 and -9.3, respectively. These findings suggest that ALD may exert a synergistic effect comparable to or greater than that of enzalutamide (ENZ) in inhibiting AR. How-ever, its specific anticancer and anti-metastatic mechanisms in prostate cancer remain unclear.

Methods

The cytotoxic effects of ALD were evaluated on PC3 and DU145 prostate cancer cells, as well as on the normal prostate cell line BPH-1. Cell viability was assessed using the EZ-Cytotoxic kit, while colony formation assays and TUNEL staining were used to meas-ure proliferation and apoptosis, respectively. Apoptosis was further analyzed through an-nexin V-FITC/PI staining and quantified by flow cytometry (FACS). Western blotting was performed to elucidate the underlying molecular mechanisms. Additionally, mito-chondrial membrane potential (ΔΨm) and intracellular calcium levels were measured to evaluate mitochondrial function, while reactive oxygen species (ROS) generation was assessed with and without pretreatment with N-acetylcysteine (NAC) .

Results

ALD selectively reduced the viability of PC3 and DU145 prostate cancer cells while spar-ing BPH-1 normal prostate cells, demonstrating cancer-selective cytotoxicity. ALD dis-rupted mitochondrial function by reducing ΔΨm and increasing intracellular calcium lev-els. A concentration-dependent increase in ROS generation was observed in PC3 and DU145 cells, which was completely inhibited by NAC pretreatment, confirming a ROS-mediated mechanism. Colony formation assays revealed a significant reduction in prolif-eration, while TUNEL and annexin V-FITC/PI staining indicated enhanced apoptosis. Western blot analysis showed that ALD modulates critical survival pathways, leading to apoptotic cell death.

Discussion

These findings demonstrate that ALD exerts potent anticancer effects against metastatic prostate cancer cells through ROS-mediated apoptosis and mitochondrial dysfunction, while exhibiting minimal cytotoxicity toward normal prostate cells. The presence of ac-tive compounds such as Atractylenolide II and III suggests a synergistic interaction that enhances AR inhibition and promotes apoptosis. ALD's ability to engage multiple path-ways highlights its therapeutic potential as a selective and multifaceted treatment for ag-gressive prostate cancer.

Atractylenolide II regulates the proliferation, ferroptosis, and immune escape of hepatocellular carcinoma cells by inactivating the TRAF6/NF-κB pathway

Hepatocellular carcinoma (HCC) is a common and lethal tumor worldwide. Atractylenolide II (AT-II) is a natural sesquiterpenoid monomer, with anti-tumor effect. To address the effect and mechanisms of AT-II on HCC. The role and mechanisms of AT-II were assessed through cell counting kit-8, flow cytometry, enzyme-linked immunosorbent assay, immunofluorescence, and western blot experiments in Hep3B and Huh7 cells. In vivo experiments were conducted in BALB/c nude mice using immunohistochemistry and western blot assays. AT-II decreased the cell viability of Hep3B and Huh7 cells with a IC50 of 96.43 µM and 118.38 µM, respectively. AT-II increased relative Fe2+ level, which was further promoted with the incubation of erastin and declined with the ferrostatin-1 in Hep3B and Huh7 cells. AT-II enhanced the level of ROS and MDA, but reduced the GSH level, and the expression of xCT and GPX4. AT-II elevated the percent of CD8+ T cells and the IFN-γ contents, and declined the IL-10 concentrations and the expression of PD-L1 in Hep3B and Huh7 cells. AT-II downregulated the relative protein level of TRAF6, p-p65/p-65, and p-IkBα/IkBα, which was rescued with overexpression of TRAF6. Upregulation of TRAF6 also reversed the effect of AT-II on proliferation, ferroptosis, and immune escape in Hep3B cells. In vivo, AT-II reduced tumor volume and weight, the level of GPX4, xCT, and PD-L1, and the expression of TRAF6, p-p65/p-65, and p-IkBα/IkBα, with the increased expression of CD8. AT-II modulated the proliferation, ferroptosis, and immune escape of HCC cells by downregulating the TRAF6/NF-κB pathway.

Antitumour mechanisms of traditional Chinese medicine elicited by regulating tumour-associated macrophages in solid tumour microenvironments

Tumour-associated macrophages (TAMs), particularly M2-TAMs, constitute the largest proportion of immune cells in the solid tumour microenvironment, playing a crucial role in tumour progression and correlating with poor prognosis. TAMs promote the proliferation, invasion, and metastasis of tumour cells by remodelling the extracellular matrix, inhibiting immunity, promoting immune escape and tumour angiogenesis, and affecting cell metabolism. Traditional Chinese medicine (TCM) has been used clinically in China for millennia. Chinese herbs exhibit potent antitumour effects with minimal to no toxicity, substantially contributing to prolonging the lives of patients with cancer and improving their quality of life. TCM has unique advantages in improving the solid tumour microenvironment, particularly in regulating TAMs to further inhibit tumour angiogenesis, reduce drug resistance, reverse immunosuppression, and enhance antitumour immunity. This review highlights the TAM-associated mechanisms within the solid tumour microenvironment, outlines the recent advancements in TCM targeting TAMs for antitumour effects, emphasises the superiority of combining TCM with standard treatments or new nano-drug delivery systems, and evaluates the safety and efficacy of TCM combined with conventional treatments via clinical trials to provide insights and strategies for future research and clinical treatment.

Atractylenolide II Suppresses Glycolysis and Induces Apoptosis by Blocking the PADI3-ERK Signaling Pathway in Endometrial Cancer Cells

Atractylenolide II (AT-II), the major bioactive compound of Atractylodes macrocephala, exhibits anti-cancer activity against many types of tumors, but the roles and the potential mechanisms in endometrial cancer remain unclear. In the present study, AT-II treatment was found to significantly suppress RL95-2 and AN3CA cell proliferation and glycolysis, and induced their apoptosis by inactivating the ERK signaling pathway, accompanied by the changing expression of the glycolytic key enzymes and apoptotic-related proteins. Peptidyl arginine deiminase 3 (PADI3), as the candidate target gene of AT-II, was highly expressed in the endometrial cancer tissues and associated with a poor prognosis according to bioinformatics analysis. PADI3 knockdown inhibited proliferation and glycolysis in endometrial cancer cells and induced cell apoptosis. Furthermore, AT-II negatively regulated the expression of PADI3, and PADI3 overexpression reversed the effects of AT-II on endometrial cancer cells. Our findings suggested that the anti-cancer function of AT-II is associated with the suppression of glycolysis and induction of apoptosis by blocking the PADI3-ERK signaling pathway. Thus, AT-II represents a novel therapeutic target for endometrial cancer and targeting AT-II may serve as a potential strategy for the clinical therapy of endometrial cancer.

Chemical Constitution, Pharmacological Effects and the Underlying Mechanism of Atractylenolides: A Review

Atractylenolides, comprising atractylenolide I, II, and III, represent the principal bioactive constituents of Atractylodes macrocephala, a traditional Chinese medicine. These compounds exhibit a diverse array of pharmacological properties, including anti-inflammatory, anti-cancer, and organ-protective effects, underscoring their potential for future research and development. Recent investigations have demonstrated that the anti-cancer activity of the three atractylenolides can be attributed to their influence on the JAK2/STAT3 signaling pathway. Additionally, the TLR4/NF-κB, PI3K/Akt, and MAPK signaling pathways primarily mediate the anti-inflammatory effects of these compounds. Atractylenolides can protect multiple organs by modulating oxidative stress, attenuating the inflammatory response, activating anti-apoptotic signaling pathways, and inhibiting cell apoptosis. These protective effects extend to the heart, liver, lung, kidney, stomach, intestine, and nervous system. Consequently, atractylenolides may emerge as clinically relevant multi-organ protective agents in the future. Notably, the pharmacological activities of the three atractylenolides differ. Atractylenolide I and III demonstrate potent anti-inflammatory and organ-protective properties, whereas the effects of atractylenolide II are infrequently reported. This review systematically examines the literature on atractylenolides published in recent years, with a primary emphasis on their pharmacological properties, in order to inform future development and application efforts.

STAT3 signaling in prostate cancer progression and therapy resistance: An oncogenic pathway with diverse functions

The categorization of cancers demonstrates that prostate cancer is the most common malignancy in men and it causes high death annually. Prostate cancer patients are diagnosed mainly via biomarkers such as PSA test and patients show poor prognosis. Prostate cancer cells rapidly diffuse into different parts of body and their metastasis is also a reason for death. Current therapies for prostate cancer patients include chemotherapy, surgery and radiotherapy as well as targeted therapy. The progression of prostate cancer cells is regulated by different factors that STAT3 signaling is among them. Growth factors and cytokines such as IL-6 can induce STAT3 signaling and it shows carcinogenic impact. Activation of STAT3 signaling occurs in prostate cancer and it promotes malignant behavior of tumor cells. Induction of STAT3 signaling increases glycolysis and proliferation of prostate cancer cells and prevents apoptosis. Furthermore, STAT3 signaling induces EMT mechanism in increasing cancer metastasis. Activation of STAT3 signaling stimulates drug resistance and the limitation of current works is lack of experiment related to role of STAT3 signaling in radio-resistance in prostate tumor. Calcitriol, capsazepine and β-elemonic are among the compounds capable of targeting STAT3 signaling and its inhibition in prostate cancer therapy. In addition to natural products, small molecules targeting STAT3 signaling have been developed in prostate cancer therapy.

The antitumor properties of atractylenolides: Molecular mechanisms and signaling pathways

Drugs that exhibit a high degree of tumor cell selectivity while minimizing normal cell toxicity are an area of active research interest as a means of designing novel antitumor agents. The pharmacological benefits of Chinese herbal medicine-based treatments have been the focus of growing research interest in recent years. Sesquiterpenoids derived from the Atractylodes macrocephala volatile oil preparations exhibit in vitro and in vivo antitumor activity. Atracylenolides exhibit anti-proliferative, anti-metastatic, and immunomodulatory activity in a range of tumor cell lines in addition to being capable of regulating metabolic activity such that it is a promising candidate drug for the treatment of diverse cancers. The present review provides a summary of recent advances in Atractylenolide-focused antitumor research efforts.

Two Novel Sesquiterpenoid Glycosides from the Rhizomes of Atractylodes lancea

Secoatractylohexone A (1), an unprecedented secoguaiane lactone glycoside featuring 6/7 cores and dihydroxy-9-guaine-3-one 11-O-β-d-glucopyranoside (2), a 9,10-unsaturated guaiene-type glycoside possessing an uncommon scaffold, were isolated from the water-soluble portion of the ethanolic extract of Atractylodes lancea rhizomes together with five known compounds (3–7). The structures of 1 and 2 were elucidated on the basis of extensive spectroscopic data and application of the CD technique. The potential biological activities of secoatractylohexone A were predicted by network pharmacology in silico, the result of which indicated that secoatractylohexone A may be used to treat type II diabetes.

LINC00893 inhibits the progression of prostate cancer through miR-3173-5p/SOCS3/JAK2/STAT3 pathway

Background

Prostate cancer (PCa) is one of the most common malignant tumors in the male urinary system. In recent years, the morbidity and mortality of PCa have been increasing due to the limited effects of existing treatment strategies. Long non-coding RNA (lncRNA) LINC00893 was reported to inhibit the proliferation and metastasis of papillary thyroid cancer cells, but its role in PCa has not been reported. This study aims to investigate the role and underlying mechanism of LINC00893 in regulating the progression of PCa cells.

Methods

We first compared LINC00893 expression levels between PCa tissues and normal prostate tissues through TCGA database. The relative LINC00893 expression levels were further validated in 66 pairs of PCa tissues and para-cancerous normal tissues, as well as in PCa cell lines. Gain-of-function experiment was performed by transfecting PCa cell with LINC00893 expression vector, and CCK (Cell count kit)-8, 5-Ethynyl-2′-deoxyuridine (EdU) incorporation, colony information and transwell assays were conducted to assess the functional phenotypes. Dual-luciferase reporter, RNA-binding protein immunoprecipitation (RIP) and RNA pull-down assays were performed to evaluate the molecular interactions.

Results

LINC00893 was downregulated in PCa tissues and cell lines, and patients with low expression of LINC00893 were associated with a poorer overall survival rate. LINC00893 overexpression hindered the proliferation, epithelial-mesenchymal transition (EMT) as well as the migratory ability of PCa cells, and suppressed the tumorigenesis of PCa cells in nude mice. We further demonstrated that LINC00893 acted as a sponge for miR-3173-5p and inhibited its activity, which in turn regulated the suppressor of cytokine signaling 3 (SOCS3)/Janus Kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling axis.

Conclusions

Our study demonstrated that LINC00893 suppresses the progression of PCa cells through targeting miR-3173-5p/SOCS3/JAK2/STAT3 axis. Our data uncovers a novel tumor-suppressor role of LINC00893 in PCa, which may serve as a potential strategy for targeted therapy in PCa.

Grapical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02637-4.

Atractylenolide II inhibits tumor-associated macrophages (TAMs)-induced lung cancer cell metastasis

OBJECTIVE

M2-like tumor-associated macrophages (TAMs) play a crucial role in promoting tumor proliferation, angiogenesis, and metastasis. In the current study, we investigated the relationship between macrophage polarization and the antitumor effect of Atractylenolide II (AT-II) in lung cancer cells.

MATERIALS AND METHODS

Cell viability, migration, and invasion were determined by MTT assay, wound healing assay, and transwell assay, respectively. Flow cytometry analysis showed the percentage of CD206⁺ cells. Gene expression was determined by real-time PCR, western blotting, and immunofluorescence staining. Lewis lung carcinoma mouse xenograft and metastasis models were used to examine the effects of AT-II on lung cancer in vivo.

RESULTS

AT-II (2.5 and 5 µM) did not cause significant inhibition of A549 cell viability but markedly inhibited IL-4/IL-13-induced M2-like polarization, evidenced by the decreased expression of the M2 surface marker CD206, down-regulation of specific M2-marker genes (Arg-1, IL-10 and TGF-β) as well as inhibition of M2 macrophages-mediated invasion and migration of A549 cells. In addition, AT-II inhibited IL-4/IL-13-induced activation of the STAT6 signaling pathway that is vital in the M2-like polarization of macrophages. In animal models, administration of AT-II (50 mg kg^-1, i.g., QD for 21 days) significantly inhibited tumor growth, reduced pulmonary metastatic nodules, and down-regulated the percentages of M2 macrophages (F4/80⁺ and CD206⁺) in total macrophages (F4/80⁺) in tumor tissues and pulmonary metastatic nodules.

CONCLUSIONS

AT-II effectively inhibits M2-like polarization, thereby inhibiting lung cancer cell metastasis both in vivo and in vitro, revealing a novel potential strategy for the antitumor effect of AT-II.

Atractylenolide I inhibits antibiotic-induced dysbiosis of the intestinal microbiome

Background

Atractylenolide I (AT-I) is an active component that is isolated from Rhizoma Atractylodis macrocephalae and it exerts anti-apoptotic, anti-oxidant, and anti-coagulant properties, and has been widely applied in the treatment of cardiovascular and cerebrovascular diseases in China. This study aimed to investigate the effects and possible mechanism of AT-I on intestinal dysbacteriosis in a mouse model.

Methods

Mice dysbacteriosis models were established and treated with AT-I, and the intestinal microbiome of the mice were compared. Using antibiotics-induced bacterial elimination in an intestinal dysbacteriosis-associated xenograft model, the gut microbiota-mediated anti-tumor mechanism was investigated.

Results

The intestinal microbiome was changed in the dysbacteriosis mice compared to the control mice, and AT-I could affect the intestinal microbiome of the dysbacteriosis mice. Manipulation of gut bacteria in the intestines of the dysbacteriosis-associated xenograft model further confirmed that the inhibition of tumor progression by AT-I was mediated by the gut microbiota, and that the underlying mechanism involves down-regulation of TLR4/MyD88/NF-κB signaling. AT-I repressed the phosphorylation of p65-NF-κB as well as the downstream cytokines, IL-6 and IL-1β, in dysbacteriosis mice.

Conclusions

AT-I may inhibit dysbacteriosis by affecting the intestinal microbiome via the regulation of TLR4/MyD88/NF-κB signaling. The present study provides a basis for the application of AT-I as an alternative medication for treating gastrointestinal disorders.

Modulation of Long Non-Coding RNAs by Different Classes of Secondary Metabolites from Plants: A Mini-Review on Antitumor Effects

The broad pharmacological spectrum of plants is related to their secondary metabolism, which is responsible for the synthesis of different compounds that have multiple effects on cellular physiology. Among the biological effects presented by phytochemicals, their use for the prevention and treatment of cancer can be highlighted. This occurs due to several mechanisms of antitumor action demonstrated by these compounds, including regulation of the cell signaling pathways and inhibition of tumor growth. In this way, long non-coding RNAs (lncRNAs) appear to be promising targets for the treatment of cancer. Their deregulation has already been related to a variety of clinical-pathological parameters. However, the effects of secondary metabolites on lncRNAs are still restricted. For this reason, the present review aimed to gather data on phytochemicals with action on lncRNAs in order to confirm their possible antitumor potential. According to the literature, terpenoid and flavonoid are the main examples of secondary metabolites involved with lncRNAs activity. In addition, the lncRNAs H19, CASC2, HOTAIR, NKILA, CCAT1, MALAT1, AFAP1-AS1, MEG3, and CDKN2B-AS1 can be highlighted as important targets in the search for new anti-tumor agents since they act as modulating pathways related to cell proliferation, cell cycle, apoptosis, cell migration and invasion. Finally, challenges for the use of natural products as a commercial drug were also discussed. The low yield, selectivity index and undesirable pharmacokinetic parameters were emphasized as a difficulty for obtaining these compounds on a large scale and for improving the potency of its biological effect. However, the synthesis and/or development of formulations were suggested as a possible approach to solve these problems. All of these data together confirm the potential of secondary metabolites as a source of new anti-tumor agents acting on lncRNAs.

Atractylenolides (I, II, and III): a review of their pharmacology and pharmacokinetics

Atractylodes macrocephala Koidz is a widely used as a traditional Chinese medicine. Atractylenolides (-I, -II, and -III) are a class of lactone compounds derived from Atractylodes macrocephala Koidz. Research into atractylenolides over the past two decades has shown that atractylenolides have anti-cancer, anti-inflammatory, anti-platelet, anti-osteoporosis, and antibacterial activity; protect the nervous system; and regulate blood glucose and lipids. Because of structural differences, both atractylenolide-I and atractylenolide-II have remarkable anti-cancer activities, and atractylenolide-I and atractylenolide-III have remarkable anti-inflammatory and neuroprotective activities. We therefore recommend further clinical research on the anti-cancer, anti-inflammatory and neuroprotective effects of atractylenolides, determine their therapeutic effects, alone or in combination. To investigate their ability to regulate blood glucose and lipid, as well as their anti-platelet, anti-osteoporosis, and antibacterial activities, both in vitro and in vivo studies are necessary. Atractylenolides are rapidly absorbed but slowly metabolized; thus, solubilization studies may not be necessary. However, due to the inhibitory effects of atractylenolides on metabolic enzymes, it is necessary to pay attention to the possible side effects of combining atractylenolides with other drugs, in clinical application. In short, atractylenolides have considerable medicinal value and warrant further study.

The E3 Ligase PIAS1 Regulates p53 Sumoylation to Control Stress-Induced Apoptosis of Lens Epithelial Cells Through the Proapoptotic Regulator Bax

Protein sumoylation is one of the most important post-translational modifications regulating many biological processes (Flotho A & Melchior F. 2013. Ann Rev. Biochem. 82:357–85). Our previous studies have shown that sumoylation plays a fundamental role in regulating lens differentiation (Yan et al., 2010. PNAS, 107(49):21034-9.; Gong et al., 2014. PNAS. 111(15):5574–9). Whether sumoylation is implicated in lens pathogenesis remains elusive. Here, we present evidence to show that the protein inhibitor of activated STAT-1 (PIAS1), a E3 ligase for sumoylation, is implicated in regulating stress-induced lens pathogenesis. During oxidative stress-induced cataractogenesis, expression of PIAS1 is significantly altered at both mRNA and protein levels. Upregulation and overexpression of exogenous PIAS1 significantly enhances stress-induced apoptosis. In contrast, silence of PIAS1 with CRISPR/Cas9 technology attenuates stress-induced apoptosis. Mechanistically, different from other cells, PIAS1 has little effect to activate JNK but upregulates Bax, a major proapoptotic regulator. Moreover, Bax upregulation is derived from the enhanced transcription activity of the upstream transcription factor, p53. As revealed previously in other cells by different laboratories, our data also demonstrate that PIAS1 promotes SUMO1 conjugation of p53 at K386 residue in lens epithelial cells and thus enhances p53 transcription activity to promote Bax upregulation. Silence of Bax expression largely abrogates PIAS1-mediated enhancement of stress-induced apoptosis. Thus, our results demonstrated that PIAS1 promotes oxidative stress-induced apoptosis through positive control of p53, which specifically upregulates expression of the downstream proapoptotic regulator Bax. As a result, PIAS1-promoted apoptosis induced by oxidative stress is implicated in lens pathogenesis.

Atractylenolides, essential components of Atractylodes-based traditional herbal medicines: Antioxidant, anti-inflammatory and anticancer properties

The rhizome of the plant Atractylodes macrocephala Koidz is the major constituent of the Traditional Chinese Medicine Baizhu, frequently used to treat gastro-intestinal diseases. Many traditional medicine prescriptions based on Baizhu and the similar preparation Cangzhu are used in China, Korea and Japan as Qi-booster. These preparations contain atractylenolides, a small group of sesquiterpenoids endowed with antioxidant and anti-inflammatory properties. Atractylenolides I, II and III also display significant anticancer properties, reviewed here. The capacity of AT-I/II/IIII to inhibit cell proliferation and to induce cancer cell death have been analyzed, together with their effects of angiogenesis, metastasis, cell differentiation and stemness. The immune-modulatory properties of ATs are discussed. AT-I has been tested clinically for the treatment of cancer-induced cachexia with encouraging results. ATs, alone or combined with cytotoxic drugs, could be useful to treat cancers or to reduce side effects of radio and chemotherapy. Several signaling pathways have been implicated in their multi-targeted mechanisms of action, in particular those involving the central regulators TLR4, NFκB and Nrf2. A drug-induced reduction of inflammatory cytokines production (TNFα, IL-6) also characterizes these molecules which are generally weakly cytotoxic and well tolerated in vivo. Inhibition of Janus kinases (notably JAK2 and JAK3 targeted by AT-I and AT-III, respectively) has been postulated. Information about their metabolism and toxicity are limited but the long-established traditional use of the Atractylodes and the diversity of anticancer effects reported with AT-I and AT-III should encourage further studies with these molecules and structurally related natural products.

Transfer of metastatic traits via miR-200c in extracellular vesicles derived from colorectal cancer stem cells is inhibited by atractylenolide I

Cancer stem cells (CSCs) are important factors contributing to tumorigenesis. We examined whether CSCs isolated from colorectal cancer (CRC) cells possess metastatic properties that can be transferred to non-CSCs via the delivery of miR-200c enclosed in extracellular vesicles (EVs). The inhibitory effect of atractylenolide I (ATL-1), a traditional Chinese medicinal compound, on miR-200c activity and metastatic transfer was investigated. EVs were isolated from colorectal CSCs. The expression of miR-200c was evaluated in CSCs and CSC-derived EVs, and horizontal transfer of metastatic properties via EVs to non-CSCs was investigated in terms of cell behavior and phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling. CSCs isolated from metastatic CRC cells exhibited higher levels of miR-200c than those in nonmetastatic CRC cells. Overexpression of miR-200c in CSCs enhanced metastatic potential by promoting proliferation and inhibiting apoptosis, in turn leading to the release of EVs carrying an excess of miR-200c. Non-CSCs co-cultured with miR-200c-containing EVs exhibited enhanced invasion and stemness maintenance associated with PI3K/Akt/mTOR activation, demonstrating successful metastatic transfer via EV delivery. Furthermore, ATL-1 impaired the EV-mediated transfer of metastatic properties by suppressing miR-200c activity and disrupting EV uptake by non-CSCs. EVs are critical signal transducers that facilitate intercellular communication and exchange of metastatic properties, which can be controlled by ATL-1. The findings are useful in the development of microRNA-based anticancer strategies by targeting EV-mediated activity, especially using natural compounds.

Phosphoribosyl pyrophosphate synthetases 2 knockdown inhibits prostate cancer progression by suppressing cell cycle and inducing cell apoptosis

Phosphoribosyl pyrophosphate synthetases 2 (PRPS2) protein function as nucleotide synthesis enzyme that plays vital roles in cancer biology. However, the expression profile and function of PRPS2 in prostate cancer (PCa) remain to be identified. Here we investigated the expression of PRPS2 protein in human PCa and paired normal tissues by immunohistochemistry, meanwhile the regulatory effects on cell proliferation, apoptosis and growth of xenograft tumors in nude mice were evaluated in PCa cells with PRPS2 depletion. Moreover, the signaling pathways were also explored by western blot analysis and quantitative polymerase chain reaction assays. We found that PRPS2 was dramatically upregulated in prostate adenocarcinoma tissues in comparison with normal tissues, and that increased PRPS2 was linked intimately to advanced clinical stage and pT status. Functional experiments showed that knockdown of PRPS2 significantly suppressed cell growth both in vitro and in vivo. In addition, depletion of PRPS2 induced G₁ phase cell cycle arrest and elevated cell apoptosis. Silencing of PRPS2 resulted in the decreased expression of Bcl‑2 and cyclinD1 and increased levels of Bax, cleavage of caspases‑3, caspases‑9 and PARP. Furthermore, we also detected PRPS2 expression was significantly induced after DHT treatment, which implied the important role of PRPS2 in oncogenesis of PCa. Taken together, our findings elucidated that PRPS2 may be a potential novel candidate for PCa therapy.