Nitidine chloride acts as an apoptosis inducer in human oral cancer cells and a nude mouse xenograft model via inhibition of STAT3

Combating anoikis resistance: bioactive compounds transforming prostate cancer therapy

The study aims to discuss the challenges associated with treating prostate cancer (PCa), which is known for its complexity and drug resistance. It attempts to find differentially expressed genes (DEGs), such as those linked to anoikis resistance and circulating tumor cells, in PCa samples. This study involves analyzing the functional roles of these DEGs using gene enrichment analysis, and then screening of 102 bioactive compounds to identify a combination that can control the expression of the identified DEGs. In this study, 53 DEGs were identified from PCa samples including anoikis-resistant PCa cells and circulating tumor cells in PCa. Gene enrichment analysis with regards to functional enrichment of DEGs was performed. An inclusive screening process was carried out among 102 bioactive compounds to identify a combination capable of affecting and regulating the expression of selected DEGs. Eventually, gastrodin, nitidine chloride, chenodeoxycholic acid, and bilobalide were selected, as their combination demonstrated ability to modulate expression of 50 out of the 53 genes targeted. The subsequent analysis focused on investigating the biological pathways and processes influenced by this combination. The findings revealed a multifaceted and multidimensional approach to tumor regression. The combination of bioactive compounds exhibited effects on various genes including those related to production of inflammatory cytokines, cell proliferation, autophagy, apoptosis, angiogenesis, and metastasis. The current study has made a valuable contribution to the development of a combination of bioactive natural compounds that can significantly impede the development of treatment resistance in prostate tumor while countering the tumors' evasion of the immune system. The implications of this study are highly significant as it suggests the creation of an enhanced immunotherapeutic, natural therapeutic concoction with combinatorial potential.

Natural STAT3 Inhibitors for Cancer Treatment: A Comprehensive Literature Review

Cancer is one of the leading causes of mortality and morbidity worldwide, affecting millions of people physically and financially every year. Over time, many anticancer treatments have been proposed and studied, including synthetic compound consumption, surgical procedures, or grueling chemotherapy. Although these treatments have improved the daily life quality of patients and increased their survival rate and life expectancy, they have also shown significant drawbacks, including staggering costs, multiple side effects, and difficulty in compliance and adherence to treatment. Therefore, natural compounds have been considered a possible key to overcoming these problems in recent years, and thorough research has been done to assess their effectiveness. In these studies, scientists have discovered a meaningful interaction between several natural materials and signal transducer and activator of transcription 3 molecules. STAT3 is a transcriptional protein that is vital for cell growth and survival. Mechanistic studies have established that activated STAT3 can increase cancer cell proliferation and invasion while reducing anticancer immunity. Thus, inhibiting STAT3 signaling by natural compounds has become one of the favorite research topics and an attractive target for developing novel cancer treatments. In the present article, we intend to comprehensively review the latest knowledge about the effects of various organic compounds on inhibiting the STAT3 signaling pathway to cure different cancer diseases.

Apoptotic activity of genipin in human oral squamous cell carcinoma in vitro by regulating STAT3 signaling

Genipin, a natural compound derived from the fruit of Gardenia jasminoides Ellis, was reported to have activity against various cancer types. In this study, we determined the underlying mechanism for genipin-induced cell death in human oral squamous cell carcinoma (OSCC). The growth-inhibitory effects of genipin in human OSCC cells was examined by the Cell Counting Kit-8 and soft agar assays. The effects of genipin on apoptosis were assessed by nuclear morphological changes by 4',6-diamidino-2-phenylindole staining, measurement of the sub-G1 population, and Annexin V-fluorescein isothiocyanate/propidium iodide double staining. The underlying mechanism of genipin activity was analyzed by western blot analysis, subcellular fractionation of the nucleus and cytoplasm, immunocytochemistry, and quantitative real-time polymerase chain reaction. Genipin inhibited the growth of OSCC cells and induced apoptosis, which was mediated by a caspase-dependent pathway. Genipin reduced the phosphorylation of signal transducer and activator of transcription 3 (STAT3) at Tyr705 and its nuclear localization. Furthermore, inhibition of p-STAT3Tyr705 levels following genipin treatment was required for the reduction of survivin and myeloid cell leukemia-1 (Mcl-1) expression, leading to apoptotic cell death. The genipin-mediated reduction in survivin and Mcl-1 expression was caused by transcriptional and/or posttranslational regulatory mechanisms. The results provide insight into the regulatory mechanism by which genipin induces apoptotic cell death through the abrogation of nuclear STAT3 phosphorylation and suggest that genipin may represent a potential therapeutic option for the treatment of human OSCC.

The multifaceted role of STAT3 pathway and its implication as a potential therapeutic target in oral cancer

Oral cancer is one of the leading causes of cancer-related deaths, and it has become a matter of serious concern due to the alarming rise in its incidence rate worldwide. Despite recent advancements in oral cancer treatment strategies, there are no significant improvements in patient's survival rate. Among the numerous cell signaling pathways involved in oral cancer development and progression, STAT3 is known to play a multifaceted oncogenic role in shaping the tumor pathophysiology. STAT3 hyperactivation in oral cancer contributes to survival, proliferation, invasion, epithelial to mesenchymal transition, metastasis, immunosuppression, chemoresistance, and poor prognosis. A plethora of pre-clinical and clinical studies have documented the role of STAT3 in the initiation and development of oral cancer and showed that STAT3 inhibition holds significant potential in the prevention and treatment of this cancer. However, to date, targeting STAT3 activation mainly involves inhibiting the upstream signaling molecules such as JAK and IL-6 receptors. The major challenge in targeting STAT3 lies in the complexity of its phosphorylation- and dimerization-independent functions, which are not affected by disrupting the upstream regulators. The present review delineates the significance of the STAT3 pathway in regulating various hallmarks of oral cancer. In addition, it highlights the STAT3 inhibitors identified to date through various preclinical and clinical studies that can be employed for the therapeutic intervention in oral cancer treatment.

Update and New Insights on Future Cancer Drug Candidates From Plant-Based Alkaloids

Cancer is a complex multifactorial disease that results from alterations in many physiological and biochemical functions. Over the last few decades, it has become clear that cancer cells can acquire multidrug resistance to conventional anticancer drugs, resulting in tumor relapse. Thus, there is a continuous need to discover new and effective anticancer drugs. Natural products from plants have served as a primary source of cancer drugs and continue to provide new plant-derived anticancer drugs. The present review describes plant-based alkaloids, which have been reported as active or potentially active in cancer treatment within the past 4 years (2017-2020), both in preclinical research and/or in clinical trials. In addition, recent insights into the possible molecular mechanism of action of alkaloid prodrugs naturally present in plants are also highlighted.

Silymarin inhibits proliferation of human breast cancer cells via regulation of the MAPK signaling pathway and induction of apoptosis

Silymarin is a purified mixture of four isomeric flavonoids extracted from the seeds and fruit of the milk thistle plant, Silybum marianus (L.). Silymarin exhibits a wide variety of biological effects and is commonly used in traditional medicine. Therefore, the anticancer effects of silymarin on human breast cancer cells were investigated to determine its pharmacological mechanisms in vitro and in vivo. The viability and proliferation of MDA-MB- 231 and MCF-7 breast cancer cells were investigated using MTT and wound healing assays. Silymarin decreased the viability and proliferation of MDA-MB-231 and MCF-7 cells in a concentration-dependent manner. The number of apoptotic bodies, as shown by DAPI staining, was increased in a concentration-dependent manner, indicating that silymarin induces apoptosis. Additionally, changes in the expression levels of apoptosis-related proteins were demonstrated in human breast cancer cells using western blotting. Silymarin increased the levels of Bax, cleaved poly-ADP ribose polymerase, cleaved caspase-9 and phosphorylated (p-)JNK, and decreased the levels of Bcl-2, p-P38 and p-ERK1/2. Furthermore, the inhibitory effects of silymarin on MCF-7 tumor growth were investigated. In mice treated with silymarin for 3 weeks (25 and 50 mg/kg), MCF-7 tumor growth was inhibited without organ toxicity. In MCF-7 tumors, silymarin induced apoptosis and decreased p-ERK1/2 levels, as assessed using a TUNEL assay and immunohistochemistry. These results indicated that silymarin inhibited breast cancer cell proliferation both in vitro and in vivo by modulating the MAPK signaling pathway. Therefore, silymarin may potentially be used as a chemo-preventive or therapeutic agent.

Nitidine Chloride Is a Potential Alternative Therapy for Glioma Through Inducing Endoplasmic Reticulum Stress and Alleviating Epithelial-Mesenchymal Transition

Background: Malignant glioma is a lethal brain tumor that is highly resistant to standard therapy. Our research aims to explore the suppressive effects of nitidine chloride (NC) on gliomas and the mechanisms involved, showing that it is a potential agent for integrative therapy of gliomas. Methods: After glioma cells were treated with NC, several experiments were performed to evaluate NC’s antitumor effects. CCK-8 assay was used to detect viability. Transwell and 3-dimensional spheroid invasion assays were used to evaluate motility of glioma in vitro, and the sphere-formation assay showed NC’s influence on glioma stem cells. Apoptosis and intracellular reactive oxygen species were measured by means of flow cytometry. Subcellular structures were observed through transmission electron microscopy. Western blot analysis reflected expression of endoplasmic reticulum (ER) stress and epithelial-mesenchymal transition (EMT) marker proteins. An orthotopic xenograft model was established to investigate the tumor suppressive effects in vivo. Results: Nitidine chloride inhibited glioma cell migration and invasion in vitro, downregulated the EMT proteins, and suppressed sphere formation of glioma stem cells. Furthermore, NC induced persistent ER stress that contributed to apoptosis and reactive oxygen species production. The xenograft model showed that NC effectively restricted glioma growth and invasion in vivo. Furthermore, we confirmed the signaling pathways that ER stress downregulates C/EBPβ and slug, as well as inhibition of the AKT/GSK3β/β-catenin axis caused by NC, in U-87 MG. Conclusion: We demonstrated that NC inhibits gliomas in vitro and in vivo by activating ER stress and downregulating EMT, which provides a basis for glioma therapy.

The inhibitory effect of TU-100 on hepatic stellate cell activation in the tumor microenvironment

INTRODUCTION

The tumor microenvironment is involved in acquiring tumor malignancies of colorectal liver metastasis (CRLM). We have reported that TU-100 (Daikenchuto) suppresses hepatic stellate cell (HSC) activation in obstructive jaundice. In this study, we report new findings as the direct and indirect inhibitory effects of TU-100 on cancer cell growth through the suppression of HSC activation.

MATERIALS AND METHODS

The HSCs (LX2) were cultured in colon cancer cells (HCT116 and HT29)-conditioned medium (CM) with or without TU-100 treatment (90, 270, 900 μg/ml). Activated HSCs (aHSCs) were detected by α-SMA and IL-6 mRNA expressions and cytokine arrays of HSC's culture supernatants. Cancer cell growth was analyzed for proliferation and migration ability, compared with TU-100 treatment. To investigate the direct anti-tumor effect of TU-100, cancer cells were cultured in the presence of aHSC-CM and TU-100 (90, 270, 900) or aHSC-CM alone, and assessed autophagosomes, conversion to LC3-II protein, and Beclin-1 mRNA expression.

RESULTS

Colon cancer-CM significantly increased α-SMA and IL-6 mRNA expressions of aHSC. α-SMA and IL-6 mRNA expressions of aHSC, and IL-6 secretions from aHSCs were significantly decreased with TU-100 (270, 900) treatment, compared to colon cancer-CM alone. Compared with normal culture medium, aHSC-CM led to a significantly increased cell number and modified HSC-CM (TU-100; 270, 900) significantly suppressed cancer cell growth and migration. TU-100 (900) treatment induced autophagy and significantly promoted the autophagic cell death.

CONCLUSIONS

TU-100 inhibited colon cancer cell malignant potential by both suppressing HSC activation and inducing directly autophagy of cancer cells.

Targeting STAT3 in Cancer Immunotherapy

As a point of convergence for numerous oncogenic signaling pathways, signal transducer and activator of transcription 3 (STAT3) is central in regulating the anti-tumor immune response. STAT3 is broadly hyperactivated both in cancer and non-cancerous cells within the tumor ecosystem and plays important roles in inhibiting the expression of crucial immune activation regulators and promoting the production of immunosuppressive factors. Therefore, targeting the STAT3 signaling pathway has emerged as a promising therapeutic strategy for numerous cancers. In this review, we outline the importance of STAT3 signaling pathway in tumorigenesis and its immune regulation, and highlight the current status for the development of STAT3-targeting therapeutic approaches. We also summarize and discuss recent advances in STAT3-based combination immunotherapy in detail. These endeavors provide new insights into the translational application of STAT3 in cancer and may contribute to the promotion of more effective treatments toward malignancies.

Targeting X chromosome-linked inhibitor of apoptosis protein in mucoepidermoid carcinoma of the head and neck: A novel therapeutic strategy using nitidine chloride

Nitidine chloride (NC) was recently reported to exhibit a wide range of pharmacological properties for several diseases, including cancer. Here we report for the first time that NC is a potential therapeutic agent for mucoepidermoid carcinoma (MEC) occurring in the head and neck because it suppresses X chromosome-linked inhibitor of apoptosis protein (XIAP) in human MEC in vitro and in vivo. The antitumor effects of NC were evaluated by trypan blue exclusion assay, western blotting, live/dead assay, 4',6-diamidino-2-phenylindole (DAPI) staining, human apoptosis antibody array, immunofluorescence staining, immunohistochemistry, small interfering RNA assay, transient transfection of XIAP overexpression vector, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, and histopathological examination of organs. NC inhibited cell viability and induced caspase-dependent apoptosis in vitro. A human apoptosis antibody array assay showed that XIAP is suppressed by NC treatment. XIAP was overexpressed in oral squamous cell carcinoma (OSCC) tissues that arose from the head and neck, and high XIAP expression was correlated with poor prognosis in OSCC patients. XIAP depletion significantly increased apoptosis, and ectopic XIAP overexpression attenuated the apoptosis induced by NC treatment. NC suppressed tumor growth in vivo at a dosage of 5 mg/kg/day. The number of TUNEL-positive cells increased and the protein expression of XIAP was consistently downregulated in NC-treated tumor tissues. In addition, NC caused no histopathological changes in the liver or kidney. These findings provide new insights into the mechanism of action underlying the anticancer effects of NC and demonstrate that NC is a promising therapeutic agent for the treatment of human MEC of the head and neck. KEY MESSAGES: • Nitidine chloride induces caspase-dependent apoptosis in MEC of the head and neck. • High XIAP expression correlates with poor prognosis of OSCC patients. • Nitidine chloride suppresses tumor growth in vivo without any systemic toxicities. • Targeting XIAP is a novel chemotherapeutic strategy for MEC of the head and neck.

Cryptotanshinone chemosensitivity potentiation by TW-37 in human oral cancer cell lines by targeting STAT3-Mcl-1 signaling

Background

Despite being one of the leading cancer types in the world, the diagnosis of oral cancer and its suitable therapeutic options remain limited. This study aims to investigate the single and chemosensitizing effects of TW-37, a BH3 mimetic in oral cancer, on human oral cancer cell lines.

Methods

We assessed the single and chemosensitizing effects of TW-37 in vitro using trypan blue exclusion assay, Western blotting, DAPI staining, Annexin V–FITC/PI double staining, and quantitative real-time PCR. Mcl-1 overexpression models were established by transforming vector and transient transfection was performed to test for apoptosis

Results

TW-37 enhanced the cytotoxicity of human oral cancer cell lines by inducing caspase-dependent apoptosis, which correlates with the reduction of the myeloid cell leukemia-1 (Mcl-1) expression via transcriptional and post-translational regulation. The ectopic expression of Mcl-1 partially attenuated the apoptosis-inducing capacity of TW-37 in human oral cancer cell lines. Besides, TW-37 decreased the phosphorylation of signal transducer and activator of transcription 3 (STAT3) at Tyr⁷⁰⁵ and nuclear translocation in human oral cancer cell lines at the early time points. Furthermore, TW-37 potentiated chemosusceptibility of cryptotanshinone in human oral cancer cell lines by suppressing STAT3–Mcl-1 signaling compared with either TW-37 or cryptotanshinone alone, resulting in potent apoptosis.

Conclusions

This study not only unravels the single and chemosensitizing effects of TW-37 for treatment of human oral cancer but also highlights the likelihood of TW-37 as a good therapeutic strategy to enhance the prognosis of patients with oral cancer in the future.

Nitidine chloride inhibits the appearance of cancer stem-like properties and regulates potential the mitochondrial membrane alterations of colon cancer cells

Background

Nitidine chloride (NC) is a natural alkaloid that can inhibit tumor growth and induce apoptosis in varieties of cancers. However, the effec12/268t of NC on colon cancer (CC) cells has not been extensively studied.

Methods

Conlon cancer SW480 cells was treated with different concentrations of NC (0.25, 0.5, 1, 2.5, 5, 10, 25, 50, 100, and 200 µM) in DMEM medium for 24 hours. Western blotting (WB) was used to detect the expression of related proteins, such as Ki67, PCNA, NANOG, SOX2, OCT4, Bcl-2, Bax, Caspase-3, Caspase-9, ERK1/2, p-ERK1/2, AKT, p-AKT, STAT3, p-STAT3, P65 and p-P65. The pellet formation experiment was used to detect the pellet formation of stem cells. The JC-1 experiment was used to detect the change of mitochondrial membrane potential. Kit was performed to detect the activity of superoxide dismutase (SOD) and the content of malondialdehyde (MDA). In vivo experiments were used to verify the results of in vitro experiments. TUNEL assay was designed to detect the apoptosis in mice tissue. IHC was used to detect expression of Ki67 and OCT4 protein in tissue.

Results

NC significantly inhibited the expression levels of Ki-67 and a proliferating cell nuclear antigen (PCNA). NC can reduce the pellet colony and pellet size of tumor stem cells and block the stem cell characteristics of CC cells. The corresponding stem cell marker molecules NANOG, SOX2, and OCT4 were also downregulated. NC treatment induced the mitochondrial membrane potential depolarization of CC cells. The expression of pro-apoptotic proteins such as caspase-3, caspase-9, and Bax were upregulated, while the expression level of apoptotic Bcl-2 was significantly down-regulated. Moreover, NC reduced SOD activity and MDA content in CC cells. In addition, studies on pathway phosphorylation have shown that NC inhibits the expression of p-erk and p-akt proteins. Finally, the results were further confirmed by experiments in nude mice. NC inhibited tumor growth in mice. NC promoted apoptosis in tissues. NC inhibited the expression of Ki67 and OCT4 in tissues. NC inhibited the phosphorylation of pathway proteins ERK1/2 and AKT in tissues.

Conclusions

NC treatment inhibited the proliferation and stemness of CC tissues, promoted the apoptosis of tumor tissues, downregulated the expression of p-ERK and p-AKT in tumor tissues, which suggests that NC may play an important role in regulating ERK and AKT pathways.

Antitumor functions and mechanisms of nitidine chloride in human cancers

Nitidine chloride (NC), a quaternary ammonium alkaloid, exhibits multiple biological activities, including antimalarial, antifungal, and antiangiogenesis. Recently, NC has been characterized to perform antitumor activity in a variety of malignancies. NC has been identified to suppress cell proliferation, stimulate apoptosis, and induce cell cycle arrest, retard migration, invasion and metastasis. Moreover, NC is reported to sensitize cancer cells to chemotherapeutic drugs. In this review article, we describe the functions of NC in human cancers and discuss the molecular insight into NC-involved antitumor feature. This review article will stimulate the deeper investigation for using NC as a potent agent for the management of cancer patients.

Natural Products and Synthetic Analogs as a Source of Antitumor Drugs

Cancer is a heterogeneous disease and one of the major issues of health concern, especially for the public health system globally. Nature is a source of anticancer drugs with abundant pool of diverse chemicals and pharmacologically active compounds. In recent decade, some natural products and synthetic analogs have been investigated for the cancer treatment. This article presents the utilization of natural products as a source of antitumor drugs.

Pseudolaric Acid B Induces Growth Inhibition and Caspase-Dependent Apoptosis on Head and Neck Cancer Cell lines through Death Receptor 5

Pseudolaric Acid B (PAB), diterpenoid isolated from the root bark of Pseudolarix kaempferi Gordon tree (Pinaceae), exhibits an anti-proliferative and apoptotic activity in various cancer cell lines but to date, the effects of PAB on head and neck cancer (HNC) cell lines remain to be elucidated. In this study, we showed that PAB significantly inhibited the viability and caspase-dependent apoptosis in HN22 cell line. PAB-induced apoptosis is through inducing death receptor 5 (DR5) together with the increase in the expression of cleaved caspase-8. It also inhibited the proliferations and induced apoptosis through DR5 in other three HNC cell lines (HSC3, Ca9.22, and HSC4). Extending our in vitro findings, we found that ethanol extract of Pseudolarix kaempferi (2.5 mg/kg/day) reduced tumor growth in a xenograft model bearing HN22 cell line without any change in body weight. DR5 were also found to be increased in tumors tissue of PAB-treated mice without any apparent histopathological changes in liver or kidney tissues. Taken together, PAB may be a potential lead compound for chemotherapeutic agents against head and neck cancer.

A new insight into the apoptotic effect of nitidine chloride targeting Checkpoint kinase 2 in human cervical cancer in vitro

Nitidine chloride (NC), a natural, bioactive, phytochemical alkaloid derived from the roots of Zanthoxylum nitidum, has been reported to exhibit anti-tumor activity against various types of cancer. However, the potential therapeutic role of NC in human cervical cancer has not yet been studied. We are the first to report that NC acts as a potential apoptosis-inducing agent for human cervical cancer in vitro. NC treatment of human cervical cancer cell lines induced caspase-mediated apoptosis, thereby reducing cell viability. Phospho-kinase proteome profiling using a human phospho-kinase array revealed that NC treatment phosphorylated Checkpoint kinase 2 (Chk2) at Thr68, which activates Chk2 in both cell lines. We also found that NC significantly affected the p53/Bim signaling axis, which was accompanied by mitochondrial membrane depolarization and cytochrome c release from the mitochondria into the cytosol. In addition, NC profoundly increased phosphorylation of the histone variant H2AX at Ser139, a typical marker of DNA damage. Taken together, these results provide in vitro evidence that NC can increase Chk2 activation, thereby acting as an attractive cell death inducer for treatment of human cervical cancer.

High throughput circRNA sequencing analysis reveals novel insights into the mechanism of nitidine chloride against hepatocellular carcinoma

Nitidine chloride (NC) has been demonstrated to have an anticancer effect in hepatocellular carcinoma (HCC). However, the mechanism of action of NC against HCC remains largely unclear. In this study, three pairs of NC-treated and NC-untreated HCC xenograft tumour tissues were collected for circRNA sequencing analysis. In total, 297 circRNAs were differently expressed between the two groups, with 188 upregulated and 109 downregulated, among which hsa_circ_0088364 and hsa_circ_0090049 were validated by real-time quantitative polymerase chain reaction. The in vitro experiments showed that the two circRNAs inhibited the malignant biological behaviour of HCC, suggesting that they may play important roles in the development of HCC. To elucidate whether the two circRNAs function as "miRNA sponges" in HCC, we identified circRNA-miRNA and miRNA-mRNA interactions by using the CircInteractome and miRwalk, respectively. Subsequently, 857 miRNA-associated differently expressed genes in HCC were selected for weighted gene co-expression network analysis. Module Eigengene turquoise with 423 genes was found to be significantly related to the survival time, pathology grade and TNM stage of HCC patients. Gene functional enrichment analysis showed that the 423 genes mainly functioned in DNA replication- and cell cycle-related biological processes and signalling cascades. Eighteen hubgenes (SMARCD1, CBX1, HCFC1, RBM12B, RCC2, NUP205, ECT2, PRIM2, RBM28, COPS7B, PRRC2A, GPR107, ANKRD52, TUBA1B, ATXN7L3, FUS, MCM8 and RACGAP1) associated with clinical outcomes of HCC patients were then identified. These findings showed that the crosstalk between hsa_circ_0088364 and hsa_circ_0090049 and their competing mRNAs may play important roles in HCC, providing interesting clues into the potential of circRNAs as therapeutic targets of NC in HCC.

Contribution of p38 MAPK Pathway to Norcantharidin-Induced Programmed Cell Death in Human Oral Squamous Cell Carcinoma

Norcantharidin (NCTD), a demethylated analog of cantharidin isolated from blister beetles, has been used as a promising anticancer agent; however, the underlying function of NCTD against human oral squamous cell carcinoma (OSCC) has not been fully understood. Here, this study was aimed to investigate the apoptotic effect and molecular targets of NCTD in human OSCC in vitro and in vivo. The anticancer effects of NCTD and its related molecular mechanisms were evaluated by trypan blue exclusion assay, live/dead assay, western blotting, 4-6-Diamidino-2-Phenylindole (DAPI) staining, flow cytometric analysis, Terminal Deoxynucleotidyl Transferase dUTP Nick end Labeling (TUNEL) assay, and immunohistochemistry. NCTD significantly inhibited cell growth and increased the number of dead cells in HSC-3 and HN22 cell lines. It induced the following apoptotic phenomena: (1) the cleavages of poly (ADP-ribose) polymerase and casepase-3; (2) increase in apoptotic morphological changes (nuclear condensation and fragmentation); (3) increase in annexin V-positive cells or sub-G₁ population of cells. NCTD significantly activated the p38 mitogen-activated protein kinase (MAPK) pathway but inactivated the signal transducer and activator of transcription (STAT)3 pathway. A p38 MAPK inhibitor (SB203580) partially attenuated NCTD-induced programmed cell death (apoptosis) in both cell lines, whereas ectopic overexpression of STAT3 did not affect it. NCTD strongly suppressed tumor growth in the tumor xenograft bearing HSC-3 cells, and the number of TUNEL-positive cells increased in NCTD-treated tumor tissues. In addition, NCTD did not cause any histopathological changes in the liver nor the kidney. NCTD induced programmed cell death via the activation of p38 MAPK in OSCC. Therefore, these results suggest that NCTD could be a potential anticancer drug candidate for the treatment of OSCC.

Gene profiling of HepG2 cells following nitidine chloride treatment: An investigation with microarray and Connectivity Mapping

Nitidine chloride (NC), an inartificial bioactive alkaloid present in the root of Zanthoxylum nitidum (Roxb.) DC, is known for its versatile anti‑inflammation and anticancer capabilities. The molecular mechanisms underlying its anticancer properties, however, remain obscure. The authors of the present study demonstrated the tumor suppressive effects of NC in a human liver cancer cell line using an MTT assay. The tumor suppressive capacity of NC was also analysed in a tumor xenograft nude mouse model. Changes in tumor cell gene expression profiles following NC treatment were detected by microarray; bioinformatics analysis demonstrated that differentially expressed genes were enriched in several cancer‑associated pathways, including those initiated by transforming growth factor‑β and phosphatidylinositol 4,5‑bisphosphate 3‑kinase/RAC‑α serine/threonine‑protein kinase signaling. A Connectivity Map revealed that parthenolide, which has been identified previously as possessing anti‑inflammatory and anticancer functions, was potentially extremely similar in molecular function to NC. By screening the data from The Cancer Genome Atlas project, eight genes that were upregulated in liver cancer and significantly suppressed by NC treatment were identified. Overexpression of these genes was closely associated with advanced tumor stage and poor differentiation status. This combination of upregulated genes enabled successful identification and prediction of prognosis for liver cancer. The findings of the present study suggest that NC could inhibit the growth of liver cancer cells through several potential molecular targets and signaling pathways.

Cytotoxicity of the crude extract and constituents of the bark of Fagara tessmannii towards multi-factorial drug resistant cancer cells

ETHNOPHARMACOLOGICAL RELEVANCE

Fagara tessmannii Engl. is an African medicinal plant used in Cameroonian traditional medicine to treat various types of cancers.

AIM OF THE STUDY

This work was designed to determine the cytotoxicity of the crude extract (FTB), fractions (FTBa-d) and compounds isolated from the bark of Fagara tessmannii, namely lupeol (1), fagaramide (2), zanthoxyline (3), hesperidin (4), nitidine chloride (5), fagaridine chloride (6), and β-sitosterol-3-O-β-_D-glucopyranoside (7). The study was extended to the mode of induction of apoptosis by FTB, compounds 5 and 6.

MATERIALS AND METHODS

The resazurin reduction assay was used to evaluate the cytotoxicity of samples. The cell cycle, apoptosis, mitochondrial membrane potential (MMP), and reactive oxygen species (ROS) were measured by flow cytometry. Column chromatography was used for the purification of FTB. Meanwhile, nuclear magnetic resonance (NMR) spectroscopic analysis was applied for structural elucidation.

RESULTS

The crude extract, fractions FTBa, FTBc, FTBd as well as compounds 5 and 6 revealed cytotoxicity towards the 9 tested cancer cell lines. The IC₅₀ values ranged from 17.34 µg/mL (towards U87MG.ΔEGFR glioblastoma cells) to 40.68 µg/mL (against CCRF-CEM leukemia cells) for FTB, from 16.78 µg/mL (towards U87. MGΔEGFR cells) to 37.42 µg/mL (against CEM/ADR5000 leukemia cells) for FTBa, from 19.47 µg/mL (towards U87. MG glioblastoma cells) to 41.62 µg/mL (against CCRF-CEM cells) for FTBc, from 14.17 µg/mL (against HCT116p53^-/- colon adenocarcinoma cells) to 22.28 µg/mL (towards CEM-ADR5000 cells) for FTBd, from 1.75 µM (against CCRF-CEM cells) to 23.52 µM (against U87. MGΔEGFR cells) for compound 5, from 1.69 µM (against CCRF-CEM cells) to 22.06 µM (against HepG2 hepatocarcinoma cells) for compound 6 and from 0.02 µM (against CCRF-CEM cells) to 122.96 µM (against CEM/ADR5000 cells) for doxorubicin. FTB induced apoptosis in CCRF-CEM cells mediated by enhanced ROS production. Compound 5 induced apoptosis through caspases activation and increase ROS production. Meanwhile, 6 induced apoptosis mediated by caspases activation, MMP alteration and enhanced ROS production.

CONCLUSION

Fagara tessmannii as well as its constituents 5 and 6 revealed considerable cytotoxicity and may be suitable candidates deserving to be further explored to develop new anticancer drugs to combat sensitive and resistant phenotypes.

Nitidine chloride represses Mcl-1 protein via lysosomal degradation in oral squamous cell carcinoma

BACKGROUND

We have shown previously that nitidine chloride (NC) induces apoptosis via inhibition of signal transducer and activator of transcription 3 (STAT3). However, its downstream molecules are not fully understood yet. Here, we report that NC as STAT3 inhibitor downregulates myeloid cell leukemia-1 (Mcl-1) protein in HSC-3 and HSC-4 human oral squamous cell carcinoma (OSCC) cells and a nude mouse tumor xenograft model.

METHODS

This study investigated the effects of NC on Mcl-1 expression in HSC-3 and HSC-4 cells using Western blotting, RT-PCR, and dual-luciferase assay. Immunohistochemistry was employed to evaluate Mcl-1 expression levels in mouse tumor tissues. Construction of Mcl-1 overexpression vector and transient transfection was done to test the apoptosis of HSC-3 cells.

RESULTS

Nitidine chloride did not affect either mRNA level or promoter activity of Mcl-1, and the decrease in Mcl-1 protein by NC was caused by lysosome-dependent degradation, but not proteasome-dependent degradation. The overexpression of Mcl-1 protein in OSCC cell lines was sufficient to block the induction of apoptosis. In addition, NC strongly reduced the expression level of Mcl-1 protein compared with other STAT3 inhibitors such as cryptotanshione and S3I-201 in OSCCs.

CONCLUSIONS

Our findings suggest that NC triggers apoptosis via lysosome-dependent Mcl-1 protein degradation and could be chosen as a promising chemotherapeutic candidate against human OSCCs.

5-Hydroxy-4'-Nitro-7-Propionyloxy-Genistein Inhibited Invasion and Metastasis via Inactivating Wnt/b-Catenin Signal Pathway in Human Endometrial Carcinoma Ji Endometrial Cells

Background

Chemotherapy has been assuring more important roles in the treatment of carcinoma. Developing new types of drugs with less adverse effects and low drug resistance has become an important researching focus. The present study aimed to investigate the anticancer effects of 5-hydroxy-4′-nitro-7-propionyloxy-genistein (HNPG) and to elucidate its underlying molecular mechanism.

Material/Methods

The inhibitory effects of cell viability of HNPG were detected using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, flat plate clone formation method, and Transwell assay. The distribution of cell cycle was analyzed using flow cytometry (FCM) method. The morphological alteration, root-mean-squared roughness (Rq), average roughness (Ra), Young’s modulus, and adhesive force were measured by atomic force microscope (AFM) assay. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analysis were used to explore the possible molecular mechanism.

Results

We found that HNPG had dramatic activity against Ji Endometrial cells (JEC) in vitro, inhibited the proliferation and colony formation, attenuated invasion and migration ability, and arrested cell cycle in G1 phase, all in a dose-dependent manner. Simultaneously, cell bodies shrunk, pseudopod structures retracted, Rq and Ra were reduced, and Young’s modulus and adhesive force increased, accompanied by downregulation of β-catenin, C-Myc, Cyclin D1, matrix metalloprotease 2 (MMP-2), matrix metalloprotease 7 (MMP-7), and matrix metalloprotease 9 (MMP-9).

Conclusions

HNPG dramatically inhibited invasion and metastasis of JEC cells in vitro. Its molecular mechanism might be related to inactivation of the wnt/β-catenin signal pathway, accumulated cells in G1/S phase, inhibited cell proliferation, improved adhesive force between cells, and reduced cell plasticity and elasticity.