A Benzothiazole Derivative (5g) Induces DNA Damage And Potent G2/M Arrest In Cancer Cells.

Chemically synthesized small molecules play important role in anticancer therapy. Several chemical compounds have been reported to damage the DNA, either directly or indirectly slowing down the cancer cell progression by causing a cell cycle arrest. Direct or indirect reactive oxygen species formation causes DNA damage leading to cell cycle arrest and subsequent cell death. Therefore, identification of chemically synthesized compounds with anticancer potential is important. Here we investigate the effect of benzothiazole derivative (5g) for its ability to inhibit cell proliferation in different cancer models. Interestingly, 5g interfered with cell proliferation in both, cell lines and tumor cells leading to significant G2/M arrest. 5g treatment resulted in elevated levels of ROS and subsequently, DNA double-strand breaks (DSBs) explaining observed G2/M arrest. Consistently, we observed deregulation of many cell cycle associated proteins such as CDK1, BCL2 and their phosphorylated form, CyclinB1, CDC25c etc. Besides, 5g treatment led to decreased levels of mitochondrial membrane potential and activation of apoptosis. Interestingly, 5g administration inhibited tumor growth in mice without significant side effects. Thus, our study identifies 5g as a potent biochemical inhibitor to induce G2/M phase arrest of the cell cycle, and demonstrates its anticancer properties both ex vivo and in vivo.

Asiatic acid induces endoplasmic reticulum stress and apoptotic death in glioblastoma multiforme cells both in vitro and in vivo.

Glioblastoma multiforme (GBM) is an untreatable malignancy. Existing therapeutic options are insufficient, and adversely affect functional and non-cancerous cells in the brain impairing different functions of the body. Therefore, there is an urgent need for additional preventive and therapeutic non-toxic drugs against GBM. Asiatic acid (AsA; 2,3,23-trihydroxy-12-ursen-28-oic acid, C30 H48 O5 ) is a natural small molecule widely used to treat various neurological disorders, and the present research investigates AsA's efficacy against GBM both in vitro and in vivo. Results showed that AsA treatment (10-100 µM) decreased the human GBM cell (LN18, U87MG, and U118MG) viability, with better efficacy than temozolomide at equimolar doses. Orally administered AsA (30 mg/kg/d) strongly decreased tumor volume in mice when administered immediately after ectopic U87MG xenograft implantation (54% decrease, P ≤ 0.05) or in mice with established xenografts (48% decrease, P ≤ 0.05) without any apparent toxicity. Importantly, AsA feeding (30 mg/kg/twice a day) also decreased the orthotopic U87MG xenografts growth in nude mice as measured by magnetic resonance imaging. Using LC/MS-MS methods, AsA was detected in mice plasma and brain tissue, confirming that AsA crosses blood-brain barrier. Mechanistic studies showed that AsA induces apoptotic death by modulating the protein expression of several apoptosis regulators (caspases, Bcl2 family members, and survivin) in GBM cells. Furthermore, AsA induced ER stress (increased GRP78 and Calpain, and decreased Calnexin and IRE1α expression), enhanced free intra-cellular calcium, and damaged cellular organization in GBM cells. These experimental results demonstrate that AsA is effective against GBM, and advocate further pre-clinical and clinical evaluations of AsA against GBM.

Silibinin inhibits prostate cancer cells- and RANKL-induced osteoclastogenesis by targeting NFATc1, NF-κB, and AP-1 activation in RAW264.7 cells.

Currently, there are limited therapeutic options against bone metastatic prostate cancer (PCA), which is primarily responsible for high mortality and morbidity in PCA patients. Enhanced osteoclastogenesis is an essential feature associated with metastatic PCA in the bone microenvironment. Silibinin, an effective chemopreventive agent, is in phase II clinical trials in PCA patients but its efficacy against PCA cells-induced osteoclastogenesis is largely unknown. Accordingly, here we examined silibinin effect on PCA cells-induced osteoclastogenesis employing human PCA (PC3MM2, PC3, and C4-2B) and murine macrophage RAW264.7 cells. We also assessed silibinin effect on receptor activator of nuclear factor κB ligand (RANKL)-induced signaling associated with osteoclast differentiation in RAW264.7 cells. Further, we analyzed silibinin effect on osteomimicry biomarkers in PCA cells. Results revealed that silibinin (30-90 µM) inhibits PCA cells-induced osteoclast activity and differentiation in RAW264.7 cells via modulating expression of several cytokines (IGF-1, TGF-ß, TNF-α, I-TAC, M-CSF, G-CSF, GM-CSF, etc.) that are important in osteoclastogenesis. Additionally, in RAW264.7 cells, silibinin decreased the RANKL-induced expression and nuclear localization of NFATc1, which is considered the master regulator of osteoclastogenesis. Furthermore, silibinin decreased the RANKL-induced DNA binding activity of NFATc1 and its regulators NF-κB and AP1, and the protein expression of osteoclast specific markers (TRAP, OSCAR, and cathepsin K). Importantly, silibinin also decreased the expression of osteomimicry biomarkers (RANKL, Runx2, osteocalcin, and PTHrP) in cell culture (PC3 and C4-2B cells) and/or in PC3 tumors. Together, our findings showing that silibinin inhibits PCA cells-induced osteoclastogenesis, suggest that silibinin could be useful clinically against bone metastatic PCA.

Propyl-2-(8-(3,4-difluorobenzyl)-2',5'-dioxo-8-azaspiro[bicyclo[3.2.1] octane-3,4'-imidazolidine]-1'-yl) acetate induces apoptosis in human leukemia cells through mitochondrial pathway following cell cycle arrest.

BACKGROUND: Due to the functional defects in apoptosis signaling molecules or deficient activation of apoptosis pathways, leukemia has become an aggressive disease with poor prognosis. Although the majority of leukemia patients initially respond to chemotherapy, relapse is still the leading cause of death. Hence targeting apoptosis pathway would be a promising strategy for the improved treatment of leukemia. Hydantoin derivatives possess a wide range of important biological and pharmacological properties including anticancer properties. Here we investigated the antileukemic activity and mechanism of action of one of the potent azaspiro hydantoin derivative, (ASHD). MATERIALS AND METHODS: To investigate the antileukemic efficacy of ASHD, we have used MTT assay, cell cycle analysis by FACS, tritiated thymidine incorporation assay, Annexin V staining, JC1 staining and western blot analysis. RESULTS: Results showed that ASHD was approximately 3-fold more potent than the parent compounds in inducing cytotoxicity. Tritiated thymidine assay in conjunction with cell cycle analysis suggests that ASHD inhibited the growth of leukemic cells. The limited effect of ASHD on cell viability of normal cells indicated that it may be specifically directed to cancer cells. Translocation of phosphatidyl serine, activation of caspase 3, caspase 9, PARP, alteration in the ratio of BCL2/BAD protein expression as well as the loss of mitochondrial membrane potential suggests activation of the intrinsic pathway of apoptosis. CONCLUSION: These results could facilitate the future development of novel hydantoin derivatives as chemotherapeutic agents for leukemia.

Synthesis and antileukemic activity of novel 2-(4-(2,4-dimethoxybenzoyl)phenoxy)-1-(4-(3-(piperidin-4-yl)propyl)piperidin-1-yl)ethanone derivatives.

A series of novel 2-(4-(2,4-dimethoxybenzoyl)phenoxy)-1-(4-(3-(piperidin-4-yl)propyl) piperidin-1-yl)ethanone derivatives 9(a-e) and 10(a-g) were synthesized and characterized by (1) H NMR, IR, mass spectral, and elemental analysis. These novel compounds were evaluated for their antileukemic activity against two human leukemic cell lines (K562 and CEM) by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay. Some of the tested compounds showed good antiproliferative activity with IC(50) values ranging from 1.6 to 8.0 µm. Compound 9c, 9e, and 10f with an electron-withdrawing halogen substituent at the para position on the phenyl ring showed excellent in vitro potency against tested human leukemia cells (K562 and CEM).

Asiatic acid inhibits pro-angiogenic effects of VEGF and human gliomas in endothelial cell culture models.

Malignant gliomas are one of the most devastating and incurable tumors. Sustained excessive angiogenesis by glioma cells is the major reason for their uncontrolled growth and resistance toward conventional therapies resulting in high mortality. Therefore, targeting angiogenesis should be a logical strategy to prevent or control glioma cell growth. Earlier studies have shown that Asiatic Acid (AsA), a pentacyclic triterpenoid, is effective against glioma and other cancer cells; however, its efficacy against angiogenesis remains unknown. In the present study, we examined the anti-angiogenic efficacy of AsA using human umbilical vein endothelial cells (HUVEC) and human brain microvascular endothelial cells (HBMEC). Our results showed that AsA (5-20 µM) inhibits HUVEC growth and induces apoptotic cell death by activating caspases (3 and 9) and modulating the expression of apoptosis regulators Bad, survivin and pAkt-ser473. Further, AsA showed a dose-dependent inhibition of HUVEC migration, invasion and capillary tube formation, and disintegrated preformed capillary network. AsA also inhibited the VEGF-stimulated growth and capillary tube formation by HUVEC and HBMEC. Next, we analyzed the angiogenic potential of conditioned media collected from human glioma LN18 and U87-MG cells treated with either DMSO (control conditioned media, CCM) or AsA 20 µM (AsA20 conditioned media, AsA20CM). CCM from glioma cells significantly enhanced the capillary tube formation in both HUVEC and HBMEC, while capillary tube formation in both endothelial cell lines was greatly compromised in the presence of AsA20CM. Consistent with these results, VEGF expression was lesser in AsA20CM compared to CCM, and indeed AsA strongly inhibited VEGF level (both cellular and secreted) in glioma cells. AsA also showed dose-dependent anti-angiogenic efficacy in Matrigel plug assay, and inhibited the glioma cells potential to attract HUVEC/HBMEC. Overall, the present study clearly showed the strong anti-angiogenic potential of AsA and suggests its usefulness against malignant gliomas.

Synthesis and antileukemic activity of novel 4-(3-(piperidin-4-yl) propyl)piperidine derivatives.

To explore the anticancer effect associated with the piperidine framework, several (substituted phenyl) {4-[3-(piperidin-4-yl)propyl]piperidin-1-yl} methanone derivatives 3(a-i) were synthesized. Variation in the functional group at N-terminal of the piperidine led to a set of compounds bearing amide moiety. Their chemical structures were confirmed by (1) H NMR, IR and mass spectra analysis. Among these, compounds 3a, 3d and 3e were endowed with antiproliferative activity. The most active compound among this series was 3a with nitro and fluoro substitution on the phenyl ring of aryl carboxamide moiety, which inhibited the growth of human leukemia cells (K562 and Reh) at low concentration. Comparison with other derivative (3h) results shown by LDH assay, cell cycle analysis and DNA fragmentation suggested that 3a is more potent to induce apoptosis.

A small oxazine compound as an anti-tumor agent: a novel pyranoside mimetic that binds to VEGF, HB-EGF, and TNF-α.

A novel pyranoside mimetic compound, DMBO (2-(2,6-difluorophenyl)-5-(4-methoxyphenyl)-1-oxa-3-azaspiro[5.5]undecane), was designed and synthesized. The sugar mimicking behavior of DMBO was addressed by its ability to bind several growth factors/cytokines such as vascular endothelial growth factor (VEGF), heparin-binding epidermal growth factor-like growth factor (HB-EGF), and tumor necrosis factor (TNF)-α as demonstrated by the recently developed surface plasmon resonance assay. DMBO exhibited strong anti-proliferation activity in vitro against tumor cells including a highly metastatic murine osteosarcoma cell line LM8G7 that secretes VEGF as well as two human ovarian cell lines, OVSAHO and SKOV-3, which secrete TNF-α and HB-EGF respectively. Furthermore, DMBO inhibited the metastatic activity to the mouse liver of LM8G7 cells injected from a lateral tail vein, and affected the heparan-degrading activity of LM8G7 cells. Here, we report that DMBO acts as a human heparanase inhibitor in vitro possibly as a substrate mimetic. DMBO also inhibited the migration and invasion of LM8G7 cells and angiogenic events such as endothelial cell proliferation, migration and capillary tube-like formation in vitro. More prominently, the administration of DMBO with heparin resulted in synergistic anti-tumor effects in mouse modelofosteosarcoma. These preclinical data shows the potential anti-cancer effects of DMBO.