Casticin inhibits epithelial-mesenchymal transition of liver cancer stem cells of the SMMC-7721 cell line through downregulating Twist

Casticin induces apoptosis and cytoprotective autophagy while inhibiting stemness involving Akt/mTOR and JAK2/STAT3 pathways in glioblastoma

Glioblastoma (GBM) is the most common malignant glioma. However, the current systemic drugs cannot completely cure GBM. Casticin is a methoxylated flavonol compound isolated from a traditional Chinese medicine Vitex rotundifolia L.f. and exhibits a strong antitumor activity in multiple human malignancies. This study was aimed to explore the effects and underlying mechanisms of casticin in GBM. The MTT assay and colony formation was used to evaluate the casticin-induced cell viability in GBM cells. Apoptosis was assessed by ANNEXIV/PI staining assay. Autophagy was analyzed by transmission electron microscopy and immunofluorescence assays. GBM stem cell (GSC) was analyzed by tumor-sphere formation assay and ALDEFLUOR assay. The anti-GBM effect of casticin was also determined by the U87MG xenograft model. Casticin inhibited tumor cell growth in vitro and in vivo, as well as significantly induced apoptosis and autophagy. Autophagy inhibition augmented casticin-induced apoptosis. Casticin also reduced the GSC population by suppressing Oct4, Nanog, and Sox2. Mechanistically, casticin inhibited Akt/mTOR and JAK2/STAT3 signal pathways. The antitumor effect of casticin in GBM was demonstrated by inducing apoptosis, autophagy, and reducing population of GSCs; thus, it may be a potential GBM therapeutic agent for future clinical usage.

Casticin Attenuates Stemness in Cervical Cancer Stem-Like Cells by Regulating Activity and Expression of DNMT1

OBJECTIVE

To explore whether casticin (CAS) suppresses stemness in cancer stem-like cells (CSLCs) obtained from human cervical cancer (CCSLCs) and the underlying mechanism.

METHODS

Spheres from HeLa and CaSki cells were used as CCSLCs. DNA methyltransferase 1 (DNMT1) activity and mRNA levels, self-renewal capability (Nanog and Sox2), and cancer stem cell markers (CD133 and CD44), were detected by a colorimetric DNMT activity/inhibition assay kit, quantitative real-time reverse transcription-polymerase chain reaction, sphere and colony formation assays, and immunoblot, respectively. Knockdown and overexpression of DNMT1 by transfection with shRNA and cDNA, respectively, were performed to explore the mechanism for action of CAS (0, 10, 30, and 100 nmol/L).

RESULTS

DNMT1 activity was increased in CCSLCs compared with HeLa and CaSki cells (P<0.05). In addition, HeLa-derived CCSLCs transfected with DNMT1 shRNA showed reduced sphere and colony formation abilities, and lower CD133, CD44, Nanog and Sox2 protein expressions (P<0.05). Conversely, overexpression of DNMT1 in HeLa cells exhibited the oppositive effects. Furthermore, CAS significantly reduced DNMT1 activity and transcription levels as well as stemness in HeLa-derived CCSLCs (P<0.05). Interestingly, DNMT1 knockdown enhanced the inhibitory effect of CAS on stemness. As expected, DNMT1 overexpression reversed the inhibitory effect of CAS on stemness in HeLa cells.

CONCLUSION

CAS effectively inhibits stemness in CCSLCs through suppression of DNMT1 activation, suggesting that CAS acts as a promising preventive and therapeutic candidate in cervical cancer.

Casticin Inhibits In Vivo Growth of Xenograft Tumors of Human Oral Cancer SCC-4 Cells

BACKGROUND/AIM

Casticin, one of the active components of Vitex rotundifolia L., presents biological and pharmacological activities including inhibition of migration, invasion and induction of apoptosis in numerous human cancer cells in vitro. This study aimed to assess the effects of casticin on tumor growth in a human oral cancer SCC-4 cell xenograft mouse model in vivo.

MATERIALS AND METHODS

Twenty-four nude mice were injected subcutaneously with SCC-4 cells and when palpable tumors reached a volume of 100-120 mm³ the mice were randomly divided into three groups. The control (0.1% dimethyl sulfoxide), casticin (0.2 mg/kg), and casticin (0.4 mg/kg) groups were intraperitoneally injected every two days for 18 days. Tumor volume and body weights were measured every two days.

RESULTS

Casticin significantly decreased tumor volume and weight in SCC-4 cell xenograft mice but there was no statistically significant difference between the body weights of control mice and mice treated with 0.2 mg/kg or 0.4 mg/kg casticin. Therefore, the growth of SCC-4 cells in athymic nude mice can be inhibited by casticin in vivo.

CONCLUSION

These findings support further investigations in the potential use of casticin as an oral anti-cancer drug in the future.

Casticin inhibits stemness of hepatocellular carcinoma cells via disrupting the reciprocal negative regulation between DNMT1 and miR-148a-3p

Casticin (CAS) is a polymethyl flavonoid from Fructus viticis and has multiple pharmacological activities, including anticancer. However, whether the molecular mechanism underlying CAS represses stemness characteristics in hepatocellular carcinoma (HCC) cells involves intervention in the reciprocal negative regulation between DNA methyltransferase 1 (DNMT1) and miR-148a-3p has not yet been reported. In this study, the effect of CAS on stemness characteristics of HCC cells and its mechanism were investigated. Results showed that CAS selectively reduced the viabilities of HCC cells but not L02 cells, as determined by CCK-8 assay. Importantly, the sub-cytotoxic concentrations of CAS could inhibit the stemness characteristics in HCC cells, as demonstrated by the expression of stemness biomarkers (CD44, EpCAM, Bmi1, Nanog, and Oct4), sphere forming assay, RT-qPCR, and Western blotting. In addition, CAS repressed DNMT1 activity and expression and increased miR-148a-3p. The effect of CAS on stemness characteristics was abolished by stable DNMT1 overexpression. MiR-148a-3p overexpression enhanced the reduction of CAS on stemness characteristics. DNMT1 overexpression promoted miR-148a-3p promoter hypermethylation as detected by methylation-specific PCR (MSP), which repressed its expression. Conversely, miR-148a-3p repressed DNMT1 expression by specific site binding to 3'-UTR of DNMT1 mRNA, as determined by luciferase assay. Moreover, the combination of CAS and agomir-148a-3p had robust effects on tumor suppression as compared to the sole activity of either molecule in nude mouse xenograft experiments in vivo. The findings suggested that CAS could inhibit stemness characteristics in HCC cells by interruption of the reciprocal negative regulation between DNMT1 and miR-148a-3p.

An Overview of the Potential Antineoplastic Effects of Casticin

Cancer persists as one of the leading causes of deaths worldwide, contributing to approximately 9.6 million deaths per annum in recent years. Despite the numerous advancements in cancer treatment, there is still abundant scope to mitigate recurrence, adverse side effects and toxicities caused by existing pharmaceutical drugs. To achieve this, many phytochemicals from plants and natural products have been tested against cancer cell lines in vivo and in vitro. Likewise, casticin, a flavonoid extracted from the Vitex species, has been isolated from the leaves and seeds of V. trifolia and V. agnus-castus. Casticin possesses a wide range of therapeutic properties, including analgesic, anti-inflammatory, antiangiogenic, antiasthmatic and antineoplastic activities. Several studies have been conducted on the anticancer effects of casticin against cancers, including breast, bladder, oral, lung, leukemia and hepatocellular carcinomas. The compound inhibits invasion, migration and proliferation and induces apoptosis (casticin-induced, ROS-mediated and mitochondrial-dependent) and cell cycle arrest (G0/G1, G2/M, etc.) through different signaling pathways, namely the PI3K/Akt, NF-κB, STAT3 and FOXO3a/FoxM1 pathways. This review summarizes the chemo-preventive ability of casticin as an antineoplastic agent against several malignancies.

Casticin inhibits invasion and proliferation via downregulation of β-catenin and reversion of EMT in oral squamous cell carcinoma

BACKGROUND

Casticin expresses multiple anti-cancer activities, whereas the effect of casticin on oral squamous cell carcinoma (OSCC) is still unclear. β-catenin signaling plays a crucial role in the epithelial-mesenchymal transition which is closely related to tumorigenesis. Herein, we aimed to study the functions of casticin on invasion and migration of OSCC, and clarify whether the effect of casticin on OSCC has a relationship with β-catenin signaling.

METHODS

Human OSCC cell lines UM1 and HSC-3 were treated with different concentrations of casticin. The cell viability was evaluated by MTT and soft agar colony formation. Transwell assay and wound-healing assay were performed to measure the ability of cell invasion and migration. The protein expression was assessed by Western blotting.

RESULTS

Casticin displayed inhibitory activities of cell viability, invasion, and migration on OSCC cell lines. Meanwhile, casticin could reverse EMT process and inhibit the expression of β-catenin in OSCC. Knock-down or overexpression of β-catenin could alter the effect of casticin on OSCC.

CONCLUSIONS

Casticin impaired invasion and migration of OSCC by inhibition of β-catenin and reversal of EMT and could be a potential anti-cancer bioactive agent.

Targeting liver cancer stem cells for the treatment of hepatocellular carcinoma

Liver cancer is one of the most common malignant tumors and prognosis remains poor. It has been increasingly recognized that liver cancer stem cells (LCSCs) are responsible for the carcinogenesis, recurrence, metastasis and chemoresistance of hepatocellular carcinoma (HCC). Targeting LCSCs is promising to be a new direction for the treatment of HCC. Herein, we summarize the potentially therapeutic targets in LCSCs at the level of genes, molecules and cells, such as knockout of oncogenes or oncoproteins, restoring the silent tumor suppressor genes, inhibition of the transcription factors and regulation of noncoding RNAs (including microRNAs and long noncoding RNAs) in LCSCs at the genetic level; inhibition of markers and blockade of the key signaling pathways of LCSCs at the molecular level; and inhibiting autophagy and application of oncolytic adenoviruses in LCSCs at the cellular level. Moreover, we analyze the potential targets in LCSCs to eliminate chemoresistance of HCC. Thereinto, the suppression of autophagy and Nanog by chloroquine and shRNA respectively may be the most promising targeting approaches. These targets may provide novel therapeutic strategies for the treatment of HCC by targeting LCSCs.

Casticin from Vitex species: a short review on its anticancer and anti-inflammatory properties

This short review provides an update of the anticancer and anti-inflammatory properties of casticin from Vitex species. Casticin is a polymethylflavone with three rings, an orthocatechol moiety, a double bond, two hydroxyl groups and four methoxyl groups. Casticin has been isolated from various tissues of plants in the Vitex genus: fruits and leaves of V. trifolia, aerial parts and seeds of V. agnus-castus and leaves of V. negundo. Studies have reported the antiproliferative and apoptotic activities of casticin from Vitex species. The compound is effective against many cancer cell lines via different molecular mechanisms. Studies have also affirmed the anti-inflammatory properties of casticin, with several molecular mechanisms identified. Other pharmacological properties include anti-asthmatic, tracheospasmolytic, analgesic, antihyperprolactinemia, immunomodulatory, opioidergic, oestrogenic, anti-angiogenic, antiglioma, lung injury protection, rheumatoid arthritis amelioration and liver fibrosis attenuation activities. Clinical trials and commercial use of the casticin-rich fruit extract of V. agnus-castus among women with premenstrual syndrome were briefly discussed.

Casticin inhibits the epithelial-mesenchymal transition in ovarian carcinoma via the hedgehog signaling pathway

Casticin inhibits migration, invasion and induced apoptosis in numerous cancer cells; however, the Hedgehog (Hh) signaling pathway is a key factor in the epithelial-mesenchymal transition (EMT). The present study aimed to assess whether casticin affects the expression of members of the Hh signaling pathway and EMT effectors in ovarian carcinoma. The ovarian cancer SKOV3 cell line was incubated in the presence of various concentrations of casticin or cyclopamine. Next, the expression levels of the main Hh signaling effector glioma-associated oncogene-1 (Gli-1) and EMT-associated factors [Twist-related protein 1 (Twist1), E-cadherin and N-cadherin] were determined by western blotting and reverse transcription-quantitative polymerase chain reaction. Cell proliferation and growth were assessed using MTT and soft agar assays; cell migration and invasion was evaluated using an in vitro migration assay and a transwell invasion assay, respectively. Compared with control group values, Gli-1, Twist1 and N-cadherin expression levels were reduced, whereas E-cadherin levels were increased in the casticin- and cyclopamine-treated groups. Incubation with casticin or cyclopamine resulted in markedly reduced SKOV3 cell viability, migration and invasion, in a dose-dependent manner. To the best of our knowledge, the findings of the present study indicated for first time that casticin may inhibit EMT via Hh signaling in vitro, reducing the migratory ability of ovarian cancer cells.

Casticin inhibits interleukin-1β-induced ICAM-1 and MUC5AC expression by blocking NF-κB, PI3K-Akt, and MAPK signaling in human lung epithelial cells

The compound casticin, isolated from Vitex rotundifolia, exerts anti-inflammatory effects and causes apoptosis of cancer cells. In this study, we explored the anti-inflammatory effects of casticin and modulation of cyclooxygenase (COX)-2, intercellular adhesion molecule 1 (ICAM-1), and mucin 5AC (MUC5AC) expression in interleukin-1β (IL-1β)-activated A549 human pulmonary epithelial cells. A549 cells were treated with various concentrations of casticin (5-20 μM), and an inflammatory response was triggered with interleukin (IL)-1β cytokines. Casticin decreased levels of IL-6, tumor necrosis factor α, and IL-8 and suppressed COX-2 expression and prostaglandin E2 production. It also reduced MUC5AC, proinflammatory cytokine, and chemokine gene expression and inhibited ICAM-1 expression for monocyte adhesion in IL-1β-stimulated A549 cells. In addition, casticin inhibited phosphorylation of Akt, phosphatidylinositol 3-kinase (PI3K), and mitogen-activated protein kinase (MAPK) and blocked nuclear transcription factor kappa-B (NF-κB) subunit p65 protein translocation into the nucleus. Co-culture of NF-κB, MAPK, and PI3K inhibitors with casticin also led to more significantly suppressed ICAM-1 expression in inflammatory A549 cells. These results provide evidence that casticin has an anti-inflammatory effect by blocking proinflammatory cytokine, chemokine, and ICAM-1 expression via suppression of the PI3K/Akt, NF-κB, and MAPK signaling pathways in IL-1β-stimulated inflammatory pulmonary epithelial cells.

Casticin attenuates liver fibrosis and hepatic stellate cell activation by blocking TGF-β/Smad signaling pathway

Although many advances have been made in understanding the pathogenesis of liver fibrosis, few options are available for treatment. Casticin, one of the major flavonoids in Fructus Viticis extracts, has shown hepatoprotective potential, but its effects on liver fibrosis are not clear. In this study, we investigated the antifibrotic activity of casticin and its underlying mechanism in vivo and in vitro. Male mice were injected intraperitoneally with carbon tetrachloride (CCl4) or underwent bile duct ligation (BDL) to induce liver fibrosis, followed by treatment with casticin or vehicle. In addition, transforming growth factor-β1(TGF-β1)-activated LX-2 cells were used. In vivo experiments showed that treatment with casticin alone had no toxic effect while significantly attenuating CCl4-or BDL-induced liver fibrosis, as indicated by reductions in the density of fibrosis, hydroxyproline content, expression of α-SMA and collagen α1(I) mRNA. Moreover, casticin inhibited LX2 proliferation, induced apoptosis in a time- and dose-dependent manner in vitro. The underlying molecular mechanisms for the effect of casticin involved inhibition of hepatic stellate cell (HSC) activation and reduced the expression of matrix metalloproteinase (MMP)-2, MMP-9, tissue inhibitor of metalloproteinases (TIMP)-1 and TIMP-2 resulting from blocking TGF-β1/Smad signaling, as well as increased the apoptosis of HSCs. The results suggest that casticin has potential benefits in the attenuation and treatment of liver fibrosis.

Anti-Cancer Phytometabolites Targeting Cancer Stem Cells

Medicinal plants are a plentiful source of bioactive molecules with much structural diversity. In cancer treatment, molecules obtained from plants represent an attractive alternative to other treatments because several plant-derived compounds have exhibited lower toxicity and higher selectivity against cancer cells. In this review, we focus on the possible application of bioactive molecules obtained from plants against more primitive cell populations in cancers, cancer stem cells. Cancer stem cells are present in several kinds of tumors and are responsible for recurrences and metastases. Common anti-cancer drugs exhibit lower effectiveness against cancer stem cells because of their biological features. However, recently discovered natural phytometabolites exert cytotoxic effects on this rare population of cells in cancers. Therefore, this review presents the latest research on promising compounds from plants that can act as antitumor drugs and that mainly affect stem cell populations in cancers.

Sirtuin SIRT6 suppresses cell proliferation through inhibition of Twist1 expression in non-small cell lung cancer

SIRT6 is a member of the NAD(+)-dependent class III deacetylase sirtuin family. Current studies have revealed that SIRT6 plays important roles in the epigenetic regulation of genes expression and contribute to the proliferation, differentiation and apoptosis of cancer cells. However, the biological function of SIRT6 in lung cancer has not been elucidated. The present study showed that the mRNA and protein levels of SIRT6 were decreased in human non-small cell lung cancer (NSCLC) tissues and cell lines. MTT assay showed that overexpression of SIRT6 could inhibit the proliferation in NSCLC cells. In contrast, SIRT6 knockdown using small interfering RNA promoted NSCLC cells proliferation. On the molecular level, we found that SIRT6 inhibited the expression of Twist1 both at the mRNA and protein levels in NSCLC cells. Taken together, these results demonstrated for the first time that SIRT6 suppressed NSCLC cells proliferation via down-regulation of Twist1 expression and might provide novel therapeutic targets in the treatment of lung cancer.