Novel daidzein molecules exhibited anti-prostate cancer activity through nuclear receptor ERß modulation, in vitro and in vivo studies.

Eight novel ERß selective daidzein analogues (NCE1-8) were synthesized and their anti-cancer activity was evaluated by in vitro and in vivo methods. Cytotoxicity study, Receptor binding studies, Luciferase assay, cMYC & Cyclin D1 expression and Caspase 3, 8 & 9 activities were measured to ascertain the anticancer activity and mechanism. Uterotropic, anti-androgenic and anti-tumour activities were performed in rodents. The results revealed that NCEs produced anti-prostate cancer activity in DU145, LNCaP and PC3 cell lines and 50% more active than genistein. NCEs was significantly down-regulated cMYC & Cyclin D1 genes and elevated caspase 3 & 9 levels and did not show any difference in uterotropic, anti-androgenic activities. The tumour weight was also reduced. The NCE 1 and 2 have shown ERß selectivity in receptor binding studies. Daidzein with methyl substitution at R or R1 position exhibited more ERß selectivity and could be considered as lead molecules for anti-prostate cancer activity.

The prognostic value of cyclin D1 in breast cancer patients treated with hormonal therapy: A pilot study.

THE AIM: of the study was to determine the clinical relevance of cyclin D1 (cD1) and its association with clinicopathological parameters in breast cancer patients treated with hormonal therapy. MATERIAL AND METHODS: The study included 96 primary breast cancer patients with known clinicopathological parameters. In adjuvant setting, 44 patients were tamoxifen-treated and 52 were treated with ovarian irradiation/ablation. The cD1 status (gene amplified/nonamplified) was determined on formalin-fixed paraffin-embedded tumor tissue sections by chromogenic in situ hybridization. Associations between parameters were analyzed by Chi-square and Spearman's rank order correlation tests. Cox proportional hazards regression test was performed. Survival curves for relapse-free survival were constructed according to the Kaplan-Meier method. RESULTS: There were no significant associations between cyclin D1 and clinicopathological parameters in either patient group. Amplified cyclin D1 associated significantly with the actual relapse incidence in the ovarian ablation patient group (p = 0.01, HR = 3.1), but not in the tamoxifen-treated patient group. Estrogen receptor and cyclin D1 have proven to be independent parameters of poor outcome in the ovarian ablation patient group (p = 0.03, HR = 2.9; and p = 0.009, HR = 2.5; respectively). CONCLUSIONS: Cyclin D1 might be a candidate biomarker of poor outcome in breast cancer patients treated with ovarian ablation, suggesting its possible involvement in acquirement of hormonal resistance. The role of cyclin D1 as potential parameter of response to tamoxifen was not as pronounced.

Sesamin induces cell cycle arrest and apoptosis through p38/C-Jun N-terminal kinase mitogen-activated protein kinase pathways in human colorectal cancer cells.

Sesamin, a lignan compound, exhibits a variety of biological activities and possesses potent anticancer properties on some human cancers. However, its effect on human colorectal cancer (CRC) remains to be elucidated. To investigate the effects of sesamin on CRC cells and further to explore the mechanisms, cell viability, cell cycle and apoptosis assays were performed in this study. We found that sesamin had a selective antiproliferation of CRC cell line HCT116 in a dose- and time-dependent manner, but no obvious effect on human normal colorectal mucosa epithelial cell FHC. Further study showed that sesamin-induced cell cycle arrest and decreased the expression of Cyclin D1 significantly and dose-dependently in HCT116 cells. Moreover, sesamin dose-dependently triggered apoptosis of HCT116 but not FHC, and promoted the expression levels of proapoptotic biomarkers Bax, cleaved caspase-3 and cleaved PARP-1 and inhibited the expression of antiapoptotic biomarker Bcl-2. Western blot analysis was used to reveal the possible signaling pathways, and we found that sesamin upregulated the phosphorylation expression levels of C-Jun N-terminal kinase (JNK) and p38 except ERK1/2 in a dose-dependent way in both HCT116 and another CRC cell line SW480. Moreover, we found that the apoptosis effect induced by sesamin was partially eliminated by inhibiting JNK or p38 activation. Finally, we showed that sesamin effectively reduced the growth of xenograft tumors derived from cell lines with limited toxicity. Taken together, the potential ability of sesamin to induce cell cycle arrest and apoptosis was shown to be via the p38 and JNK mitogen-activated protein kinase signaling pathways, which may be one of the mechanisms of the anticancer activity of this low-toxic agent.

Enhanced anti-cancer activity by localized delivery of curcumin form PVA/CNCs hydrogel membranes: Preparation and in vitro bioevaluation.

This study targets to develop curcumin-loaded polyvinyl alcohol/cellulose nanocrystals (PVA/CNCs) membrane as localized delivery system for breast/liver cancer. A novel strategy was developed for enhancing encapsulation capacity and maximizing therapeutic efficiency of curcumin-loaded PVA/CNCs membranes. Membranes were prepared by solution-casting method using citric acid as crosslinker. SEM revealed that PVA/CNCs ratio (80:20) was chosen as the optimum for loading curcumin. FT-IR indicated that, curcumin was incorporated into PVA/CNCs in amorphous-phase via intermolecular hydrogen bond between curcumin and membrane components. Curcumin showed biphasic-release through burst-release of 41% of curcumin during the first hour, followed by sustained-release of 70% and 94% during 24 h and 48 h, respectively. In vitro cytotoxicity of PVA/CNCs/Curcumin membrane exhibited a selective inhibition proliferation of breast and liver cancer cells in a concentration-dependent without any toxic effect on normal cells. At high concentration (8 mg/ml) of PVA/CNCs/Curcumin, reduced viability to 35% and 7% of MCF-7 and Huh-7 cells, respectively; meanwhile high HFB-4 normal cell viability ≥80% was investigated. Antimicrobial activity of PVA/CNCs/Curcumin was investigated by multi-drug-resistant strains, and MIC values. PVA/CNCs/Curcumin membranes with concentration (40 mg/ml) showed broad-spectrum antimicrobial activities, thus inhibited ~96-99% of microbial growth. PVA/CNCs/Curcumin membranes could be as promised anti-infective biomaterials for breast and liver cancer wound healing.

LncRNA-OBFC2A targeted to Smad3 regulated Cyclin D1 influences cell cycle arrest induced by 1,4-benzoquinone.

Long-term exposure to benzene is associated with adverse health effects such as leukemia. Abnormal cell cycle progression has been reported participating in tumorigenesis. Our previous study found that lncRNA-OBFC2A was involved in benzene toxicity through regulating cell proliferation. However, the function of lncRNA-OBFC2A in the regulation of cell cycle remains obscure and the precise mechanisms need to be explored. In vitro study, results showed that benzene metabolic, 1,4-Benzoquinone (1,4-BQ), induced cell cycle arrest at the G1 phase accompanied with decreased expression of Cyclin D1 in a dose-dependently manner. Interestingly, lncRNA-OBFC2A overexpression was found in AHH-1 cells treated with 1,4-BQ and while interference with lncRNA-OBFC2A, the expression of Cyclin D1 were reversed. Further, we found that lncRNA-OBFC2A can interact with Smad3 to control cell cycle via modulating Cyclin D1 expression. In benzene exposed workers, the expression of lncRNA-OBFC2A and Smad3 increased while cyclin D1 decreased which was consistent with the in vitro experiment, meanwhile, the significant associations among them were also found. Thus, these findings indicate that lncRNA-OBFC2A targeted to Smad3 regulated cyclin D1 influences cell cycle arrest induced by 1,4-BQ. LncRNA-OBFC2A, Smad3 and Cyclin D1 as a set of biomarkers play important roles in benzene haematotoxicity.

Antihypertensive drug telmisartan inhibits cell proliferation of gastrointestinal stromal tumor cells in vitro.

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the digestive tract. The angiotensin II type 1 receptor blockers, telmisartan and candesartan, are widely used antihypertensive drugs that inhibits cancer cell proliferation; however, its underlying mechanisms in mesenchymal tumors, including GIST, remains unknown. The present study aimed to investigate the effect of telmisartan on GIST­T1 cells and its underlying mechanism. Telmisartan and candesartan inhibited the proliferation of these cells by blocking the G0 to G1 cell cycle transition, which was accompanied by a decrease in cell cycle­related proteins such as cyclin D1. Furthermore, telmisartan exposure significantly altered microRNA expression in vitro. In conclusion, telmisartan suppressed human GIST cell proliferation by inducing cell cycle arrest in vitro.

Down-Regulation of the Mammalian Target of Rapamycin (mTOR) Pathway Mediates the Effects of the Paeonol-Platinum(II) Complex in Human Thyroid Carcinoma Cells and Mouse SW1736 Tumor Xenografts.

BACKGROUND This study aimed to investigate the effects of the paeonol-platinum(II) (PL-Pt[II]) complex on SW1736 human anaplastic thyroid carcinoma cell line and the BHP7-13 human thyroid papillary carcinoma cell line in vitro and on mouse SW1736 tumor xenografts in vivo. MATERIAL AND METHODS The cytotoxic effects of the PL-Pt(II) complex on SW1736 cells and BHP7-13 cells was measured using the MTT assay. Western blot measured the expression levels of cyclins, cell apoptotic proteins, and signaling proteins. DNA content and apoptosis were detected by flow cytometry. SW1736 cell thyroid tumor xenografts were established in mice followed by treatment with the PL-Pt(II) complex. RESULTS Treatment of the SW1736 and BHP7-13 cells with the PL-Pt(II) complex reduced cell proliferation in a dose-dependent manner, with an IC50 of 1.25 µM and 1.0 µM, respectively, and increased the cell fraction in G0/G1phase, inhibited p53, cyclin D1, promoted p27 and p21 expression, and significantly increased the sub-G1 fraction. Treatment with the PL-Pt(II) complex increased caspase-3 degradation, reduced the expression of p-4EBP1, p-4E-BP1 and p-S6, and reduced the expression of p-ERK1/2 and p-AKT. Treatment with the PL-Pt(II) complex reduced the volume of the SW1736 mouse tumor xenografts on day 14 and day 21, and reduced AKT phosphorylation and S6 protein expression and increased degradation of caspase-3. CONCLUSIONS The cytotoxic effects of the PL-Pt(II) complex in human thyroid carcinoma cells, including activation of apoptosis and an increased sub-G1 cell fraction of the cell cycle, were mediated by down-regulation of the mTOR pathway.

Simvastatin ameliorates altered mechanotransduction in uterine leiomyoma cells.

BACKGROUND: Uterine leiomyomas, the most common tumors of the female reproductive system, are characterized by excessive deposition of disordered stiff extracellular matrix and fundamental alteration in the mechanical signaling pathways. Specifically, these alterations affect the normal dynamic state of responsiveness to mechanical cues in the extracellular environment. These mechanical cues are converted through integrins, cell membrane receptors, to biochemical signals including cytoskeletal signaling pathways to maintain mechanical homeostasis. Leiomyoma cells overexpress ß1 integrin and other downstream mechanical signaling proteins. We previously reported that simvastatin, an antihyperlipidemic drug, has antileiomyoma effects through cellular, animal model, and epidemiologic studies. OBJECTIVE: This study aimed to examine the hypothesis that simvastatin might influence altered mechanotransduction in leiomyoma cells. STUDY DESIGN: This is a laboratory-based experimental study. Primary leiomyoma cells were isolated from 5 patients who underwent hysterectomy at the Department of Gynecology and Obstetrics of the Johns Hopkins University Hospital. Primary and immortalized human uterine leiomyoma cells were treated with simvastatin at increasing concentrations (0.001, 0.01, 0.1, and 1 µM, or control) for 48 hours. Protein and mRNA levels of ß1 integrin and extracellular matrix components involved in mechanical signaling were quantified by quantitative real-time polymerase chain reaction, western blotting, and immunofluorescence. In addition, we examined the effect of simvastatin on the activity of Ras homolog family member A using pull-down assay and gel contraction. RESULTS: We found that simvastatin significantly reduced the protein expression of ß1 integrin by 44% and type I collagen by 60% compared with untreated leiomyoma cells. Simvastatin-treated cells reduced phosphorylation of focal adhesion kinase down to 26%-60% of control, whereas it increased total focal adhesion kinase protein expression. Using a Ras homolog family member A pull-down activation assay, we observed reduced levels of active Ras homolog family member A in simvastatin-treated cells by 45%-85% compared with control. Consistent with impaired Ras homolog family member A activation, simvastatin treatment reduced tumor gel contraction where gel area was 122%-153% larger than control. Furthermore, simvastatin treatment led to reduced levels of mechanical signaling proteins involved in ß1 integrin downstream signaling, such as A-kinase anchor protein 13, Rho-associated protein kinase 1, myosin light-chain kinase, and cyclin D1. CONCLUSION: The results of this study suggest a possible therapeutic role of simvastatin in restoring the altered state of mechanotransduction signaling in leiomyoma. Collectively, these findings are aligned with previous epidemiologic studies and other reports and support the need for clinical trials.

Gramicidin inhibits human gastric cancer cell proliferation, cell cycle and induced apoptosis.

BACKGROUND: Gastric cancer is a common malignant tumor with high morbidity and mortality worldwide, which seriously affects human health. Gramicidin is a short peptide antibiotic which could be used for treating infection induced by bacteria or fungi. However, the anti-cancer effect of gramicidin on gastric cancer cells and its underlying mechanism remains largely unknown. RESULTS: Gastric cancer cells SGC-7901, BGC-823 and normal gastric mucosal cells GES-1 were treated with different concentrations of gramicidin respectively. The results of CCK-8 experiment revealed cellular toxicity of gramicidin to cancer cells while cell colony formation assay showed that gramicidin significantly inhibited the proliferation of gastric cancer cells, but had little effect on normal gastric mucosal cells. In addition, the wound healing assay showed that gramicidin inhibited the migration of SGC-7901 cell. Meanwhile, apoptosis and cell cycle analysis revealed that gramicidin induced cell apoptosis with G2/M cell cycle inhibition. Furthermore, western blot analysis demonstrated that gramicidin down-regulated the expression of cyclinD1 and Bcl-2 as well as the FoxO1 phosphorylation. CONCLUSIONS: The current study illustrated the anti-tumor activity of gramicidin on gastric cancer cells, providing a possibility for gramicidin to be applied in clinical practice for the treatment of gastric cancer.

α-Hederin Induces Apoptosis of Esophageal Squamous Cell Carcinoma via an Oxidative and Mitochondrial-Dependent Pathway.

BACKGROUND: α-Hederin has been shown promising anti-tumor potential against various cancer cell lines. However, reports about effects of α-hederin on esophageal squamous cell carcinoma (ESCC) are still unavailable. AIM: To investigate the inhibitory effects of α-hederin on ESCC and explore the underlying mechanism. METHODS: Human esophageal carcinoma cell line (Eca-109) was used for the experiment. Cell Counting Kit-8, flow cytometry, Hoechst 33258 staining, enhanced ATP assay kit, 2',7'-dichlorofluorescin diacetate, JC-1 kit, and Western bolt were used to assess the cell viability, cycle, apoptosis, cellular ATP content, reactive oxygen species (ROS) level, mitochondrial membrane potential (MMP), and protein expression, respectively, in vitro. Xenografted tumor model was constructed to evaluate the in vivo anti-tumor effects of α-hederin. RESULTS: Compared with control group, α-hederin significantly inhibited the proliferation, induced apoptosis of ESCC, and arrested the cell cycle in G1 phase (P < 0.05). α-Hederin induced the accumulation of ROS, decrement of ATP levels, and disruption of MMP (P < 0.05). The detection of mitochondrial and cytosol proteins showed that AIF, Apaf-1, and Cyt C were released and increased in cytoplasm, and then, caspase-3, caspase-9, and Bax were involved and increased, while Bcl-2 level was decreased (P < 0.05). Furthermore, the above changes were amplified in the group pretreated with L-buthionine sulfoximine, while N-acetyl-L-cysteine plays an opposite role (P < 0.05). Meanwhile, α-hederin significantly inhibited the growth of xenografted tumors with favorable safety. CONCLUSION: α-Hederin could inhibit the proliferation and induce apoptosis of ESCC via dissipation of the MMP with simultaneous ROS generation and activation of the mitochondrial pathway.

Tylophorine reduces protein biosynthesis and rapidly decreases cyclin D1, inhibiting vascular smooth muscle cell proliferation in vitro and in organ culture.

BACKGROUND: Tylophorine (TYL) is an alkaloid with antiproliferative action in cancer cells. Vascular smooth muscle cell (VSMC) proliferation and neointima formation contribute to restenosis after percutaneous coronary interventions. HYPOTHESIS/PURPOSE: Our goal was to examine the potential of TYL to inhibit VSMC proliferation and migration, and to dissect underlying signaling pathways. STUDY DESIGN AND METHODS: TYL was administered to platelet-derived growth factor (PDGF-BB)-stimulated, serum-stimulated, quiescent and unsynchronized VSMC of rat and human origin. BrdU incorporation and resazurin conversion were used to assess cell proliferation. Cell cycle progression was analyzed by flow cytometry of propidium iodide-stained nuclei. Expression profiles of proteins and mRNAs were determined using western blot analysis and RT-qPCR. The Click-iT OPP Alexa Fluor 488 assay was used to monitor protein biosynthesis. RESULTS: TYL inhibited PDGF-BB-induced proliferation of rat aortic VSMCs by arresting cells in G1 phase of the cell cycle with an IC50 of 0.13 µmol/l. The lack of retinoblastoma protein phosphorylation and cyclin D1 downregulation corroborated a G1 arrest. Inhibition of proliferation and cyclin D1 downregulation were species- and stimulus-independent. TYL also decreased levels of p21 and p27 proteins, although at later time points than observed for cyclin D1. Co-treatment of VSMC with TYL and MG132 or cycloheximide (CHX) excluded proteasome activation by TYL as the mechanism of action. Comparable time-dependent downregulation of cyclin D1, p21 and p27 in TYL- or CHX-treated cells, together with decreased protein synthesis observed in the Click-iT assay, suggests that TYL is a protein synthesis inhibitor. Besides proliferation, TYL also suppressed migration of PDGF-activated VSMC. In a human saphenous vein organ culture model for graft disease, TYL potently inhibited intimal hyperplasia. CONCLUSION: This unique activity profile renders TYL an interesting lead for the treatment of vasculo-proliferative disorders, such as restenosis.

Anti-proliferative and anti-apoptotic potential effects of epigallocatechin-3-gallate and/or metformin on hepatocellular carcinoma cells: in vitro study.

The effects of epigallocatechin-3-gallate (EGCG) and metformin single treatment have been tested against hepatocellular carcinoma (HCC). This study aimed to assess the combination effects of EGCG and metformin on proliferation and apoptosis of HepG2cells and identified new potential molecular targets. The effect of EGCG and metformin against cell proliferation in HepG2 was determined using MTT assay. Reverse transcription polymerase chain reaction was applied to examine the gene expression of cyclin D1, lncRNA-AF085935, caspase-3, survivin and VEGF. The level of protein expression of glypican-3 was assessed by western blot. In HepG2 cells, EGCG and metformin combination treatment exhibited high significant effect against tumor proliferation. It significantly reduced cyclin D1, lncRNA-AF085935, glypican-3 and promoted apoptosis through increasing caspase3 and decreasing survivin compared to control cells. Moreover, EGCG and metformin treated cells showed decreased expression levels of VEGF. Our study provided new insights of the anticarcinogenic effects of EGCG and metformin on HCC through their effects on glypican-3 and lncRNA-AF085935.

Synthesis of novel guttiferone E and xanthochymol derivatives with cytotoxicities by inducing cell apoptosis and arresting the cell cycle phase.

The mixture of GX (guttiferone E and xanthochymol), an inseparable polycyclic polyprenylated acylphloroglucinol (PPAP), showed moderate cytotoxic activities. The chemical transformation of GX yielded three different types of PPAPs (1, 2, and 3/4). A series of analogs were prepared, and the structures of the 40 newly synthesized compounds were elucidated by 1D and 2D NMR and HR-ESI-MS. The derivatives were screened in vitro for antiproliferative activity against five human cancer cell lines: human leukemic cell lines (HEL and K562), cervical cancer cell line (Hela), human breast adenocarcinoma cell line (MCF-7), and human non-small cell lung cancer cell line (A549), using the MTT assay, and most of the derivatives showed good cytotoxic activities. Noticeably, compound 2, a novel tautomer with a hemiketal, exhibited selective cytotoxic activities against HEL (IC50 = 4.79 ±â€¯0.23 µM) and K562 (IC50 = 7.69 ±â€¯0.34 µM) leukemia cells. The mechanism studies indicated that compound 2 induced apoptosis and arrested the cell cycle at the G0/G1 phase in the HEL cell line. Furthermore, compound 2 activated the intrinsic pathway by reducing the expression of anti-apoptotic protein Bcl-2 and cell cycle-specific cyclin D1 and by enhancing the pro-apoptotic protein Bax. Moreover, the caspase-3 and PPRP1 levels were also upregulated. Our present results suggest that compound 2 is a potential candidate for developing novel anti-leukemia agents in the future.

Gramicidin inhibits human gastric cancer cell proliferation, cell cycle and induced apoptosis

BACKGROUND: Gastric cancer is a common malignant tumor with high morbidity and mortality worldwide, which seriously affects human health. Gramicidin is a short peptide antibiotic which could be used for treating infection induced by bacteria or fungi. However, the anti-cancer effect of gramicidin on gastric cancer cells and its underlying mechanism remains largely unknown. RESULTS: Gastric cancer cells SGC-7901, BGC-823 and normal gastric mucosal cells GES-1 were treated with different concentrations of gramicidin respectively. The results of CCK-8 experiment revealed cellular toxicity of gramicidin to cancer cells while cell colony formation assay showed that gramicidin significantly inhibited the proliferation of gastric cancer cells, but had little effect on normal gastric mucosal cells. In addition, the wound healing assay showed that gramicidin inhibited the migration of SGC-7901 cell. Meanwhile, apoptosis and cell cycle analysis revealed that gramicidin induced cell apoptosis with G2/M cell cycle inhibition. Furthermore, western blot analysis demonstrated that gramicidin down-regulated the expression of cyclinD1 and Bcl-2 as well as the FoxO1 phosphorylation. CONCLUSIONS: The current study illustrated the anti-tumor activity of gramicidin on gastric cancer cells, providing a possibility for gramicidin to be applied in clinical practice for the treatment of gastric cancer.

Marsdenia Tenacissima Extract Inhibits Proliferation and Promotes Apoptosis in Human Ovarian Cancer Cells.

BACKGROUND Marsdenia tenacissima extract (MTE) is a traditional Chinese medicine that can be effectively used against various cancers. However, to the best of our knowledge, its role in ovarian cancer is not known. This study investigated the effects of MTE on human ovarian cancer SKOV3 cells. MATERIAL AND METHODS The viability and cell cycle of SKOV3 cells were assessed using the cell counting kit-8 (CCK-8) and propidium Iodide (PI) staining kit, respectively. Cell apoptosis and mitochondrial membrane potential (MMP) were detected by flow cytometry. The expression levels of proliferation-related and apoptosis-related factors were tested by quantitative real-time PCR (qRT-PCR) and Western blot assays, respectively. RESULTS We found that MTE markedly reduced the viability of SKOV3 cells in dose-dependent and time-dependent manners. MTE induced cell cycle arrest by downregulating the levels of cyclin D1and cyclin B1. MTE (10, 20, and 40 mg/mL) markedly increased apoptosis rates (2.77±0.6%, 4.95±0.97%, and 12.16±0.69%, respectively), and enhanced the loss of MMP. MTE obviously downregulated the expression of B cell lymphoma-2 (Bcl-2) and upregulated the expression levels of fibroblast-associated (Fas), Fas ligand (FasL), cleaved cysteinyl aspartate-specific proteinas-3 (caspase-3), and Bcl-2-associated X protein (Bax) compared to the control group. In addition, the expressions of phosphorylated mammalian target of rapamycin (p-mTOR), phosphorylated protein kinase B (p-AKT), and phosphorylated-phosphatidylinositol 3 kinase (p-PI3K) were decreased by MTE. CONCLUSIONS MTE inhibited proliferation and induced apoptosis of SKOV3 cells. The depression of the PI3K/AKT/mTOR pathway may augment the protective effect of MTE. Thus, MTE might be expected to be a new drug for curing ovarian cancer.

Shikonin enhances sensitization of gefitinib against wild-type EGFR non-small cell lung cancer via inhibition PKM2/stat3/cyclinD1 signal pathway.

AIMS: Mutant EGFR Non-small cell lung cancer has benefit from gefitinib, but it has limited effect for wild-type EGFR tumors. Shikonin, a natural naphthoquinone isolated from a traditional Chinese medicine, the plant Lithospermum erythrorhizon (zicao), not only can inhibit the tumor growth, but also overcome cancer drug resistance. Our aim is to investigate whether shikonin can enhance antitumor effect of gefitinib in EGFR wild-type lung cancer cells in vitro and in vivo. MATERIALS AND METHODS: CCK-8 was used to determine the proliferation of EGFR wild-type non-small cell lung cancer. Apoptosis and cell cycle were detected by flow cytometry. PKM2, STAT3, p-STAT3 and cyclinD1 were detected by Western blot. A549 tumor model was established to observe the antitumor effect of shikonin combination with gefitinib in vivo. KEY FINDINGS: The results showed that combination of shikonin with gefitinib exhibited synergistic antitumor effect in vitro and in vivo. Its potential molecular mechanisms may be associated with inhibition of PKM2/STAT3/cyclinD1. SIGNIFICANCE: These results provide a promising therapeutic approach for the treatment of wild-type EGFR non-small cell lung cancer.

A fusion antitumor peptide regulates proliferation and apoptosis of endothelial cells.

The present research has been carried out to elicit the mechanism of antiangiogenic activity of a fusion peptide P2. Peptide P2 was designed by the connection of a heptapeptide MMP inhibitor to ES-2, a fragment of Endostatin. In a previous study, P2 demonstrated strong antiangiogenic and antitumor effect, and the current work explains the antiangiogenic mechanism of P2 through endothelial cell proliferation and apoptosis. In our study, it was shown that P2 inhibited HUVECs proliferation at a low serum concentration and this effect might be achieved through arresting cell cycle by decreasing the expression level of Cyclin D1. In addition, P2 was found to induce apoptosis of HUVECs. Using Western blot, it was indicated that P2 induced the cleavage of Caspase-3, the hallmark protease of apoptosis. The activation and expression of the upstream regulator Caspase-9 can also be affected by P2 treatment. Furthermore, P2 reduced the protein level of antiangiogenic factors Bcl-xL and Bcl-2. These results revealed that P2 regulates endothelial cell apoptosis through intrinsic apoptotic pathway.

Mefloquine targets ß-catenin pathway and thus can play a role in the treatment of liver cancer.

The current study was designed and performed to investigate the effect of mefloquine on the proliferation and tumor formation potential of liver cancer stem cells. CD133 + HepG2 cells were identified using MACS and showed markedly higher tumor formation potential compared to the parental cells. The secondary tumors formed by CD133 + cells were markedly large in size and more in number compared to the parental cells. Mefloquine treatment of CD133 + HepG2 cells inhibited the proliferation selectively in concentration based manner. The rate of proliferation was inhibited to 82 and 12% in parental and CD133 + sphere forming cells, respectively on treatment with 10 µM concentration of mefloquine. The number of secondary tumors formed by primary tumors was decreased significantly on treatment with 10 µM mefloquine concentration. Treatment of the liver cancer stem cells with mefloquine markedly decreased the potential to undergo self-renewal at 10 µM concentration after 48 h. The results from western blot analysis showed significantly higher expression of cancer stem cell molecules ß-catenin and cyclin D1 in LCSCs. Treatment of the LCSCs with various concentrations of mefloquine reduced the expression levels of ß-catenin and cyclin D1. Administration of the CD133 + cell tumor xenografts in the mice led to the formation of large sized tumors in the control group. However, the tumor growth was inhibited significantly in the mice on treatment with 10 mg/kg doses of mefloquine after day 21. The tumor weight was significantly lower in the animals of mefloquine treatment group compared to the control group. Thus, mefloquine treatment inhibits self-renewal and proliferation potential of cells through targeting ß-catenin pathway.

SKLB188 inhibits the growth of head and neck squamous cell carcinoma by suppressing EGFR signalling.

BACKGROUND: Overexpression of epidermal growth factor receptor (EGFR) occurs in approximately 90% of head and neck squamous cell carcinoma (HNSCC), and is correlated with poor prognosis. Thus, targeting EGFR is a promising strategy for treatment of HNSCC. Several small molecule EGFR inhibitors have been tested in clinical trials for treatment of HNSCC, but none of them are more effective than the current chemotherapeutic drugs. Thus, it is urgently needed to develop novel EGFR inhibitors for HNSCC treatment. METHODS: By screening an in-house focused library containing approximately 650 000 known kinase inhibitors and kinase inhibitor-like compounds containing common kinase inhibitor core scaffolds, we identified SKLB188 as a lead compound for inhibition of EGFR. The anticancer effects of SKLB188 on HNSCC cells were investigated by in vitro cell growth, cell cycle and apoptosis assays, as well as in vivo FaDu xenograft mouse model. Molecular docking, in vitro kinase profiling and western blotting were performed to characterise EGFR as the molecular target. RESULTS: SKLB188 inhibited HNSCC cell proliferation by inducing G1 cell cycle arrest, which was associated with downregulating the expression of Cdc25A, cyclins D1/A and cyclin-dependent kinases (CDK2/4), and upregulating the expression of cyclin-dependent kinase (CDK) inhibitors (p21Cip1 and p27Kip1), leading to decreased phosphorylation of Rb. SKLB188 also induced caspase-dependent apoptosis of HNSCC cells by downregulating the expression of Mcl-1 and survivin. Molecular docking revealed that SKLB188 could bind to the kinase domain of EGFR through hydrogen bonds and hydrophobic interactions. In vitro kinase assay showed that SKLB188 inhibited the activity of a recombinant human EGFR very potently (IC50=5 nM). Western blot analysis demonstrated that SKLB188 inhibited the phosphorylation of EGFR and its downstream targets, extracellular signal-regulated protein kinases 1 and 2 (Erk1/2) and Akt in the cells. In addition, SKLB188 dose-dependently inhibited FaDu xenograft growth in nude mice, and concurrently inhibited the phosphorylation of Erk1/2 and Akt in the tumours. CONCLUSIONS: SKLB188 potently inhibits the growth of HNSCC cells in vitro and in vivo by targeting EGFR signalling. The results provide a basis for further clinical investigation of SKLB188 as a targeted therapy for HNSCC. Our findings may open a new avenue for development of novel EGFR inhibitors for treatment of HNSCC and other cancers.