Zerumbone Induces Apoptosis in Breast Cancer Cells by Targeting αvß3 Integrin upon Co-Administration with TP5-iRGD Peptide.

Cell-penetrating peptides (CPPs) are highly promising tools to deliver therapeutic molecules into tumours. αVß3 integrins are cell-matrix adhesion receptors, and are considered as an attractive target for anticancer therapies owing to their roles in the process of metastasis and angiogenesis. Therefore, this study aims to assess the effect of co-administration of zerumbone (ZER) and ZERencapsulated in hydroxypropyl-ß-cyclodextrin with TP5-iRGD peptide towards cell cytotoxicity, apoptosis induction, and proliferation of normal and cancerous breast cells utilizing in vitro assays, as well as to study the molecular docking of ZER in complex with TP5-iRGD peptide. Cell viability assay findings indicated that ZER and ZERencapsulated in hydroxypropyl-ß-cyclodextrin (ZER-HPßCD) inhibited the growth of estrogen receptor positivebreast cancer cells (ER+ MCF-7) at 72 h treatment with an inhibitory concentration (IC)50 of 7.51 ± 0.2 and 5.08 ± 0.2 µg/mL, respectively, and inhibited the growth of triple negative breast cancer cells (MDA-MB-231) with an IC50 of 14.96 ± 1.52 µg/mL and 12.18 ± 0.7 µg/mL, respectively. On the other hand, TP5-iRGD peptide showed no significant cytotoxicity on both cancer and normal cells. Interestingly, co-administration of TP5-iRGD peptide in MCF-7 cells reduced the IC50 of ZER from 7.51 ± 0.2 µg/mL to 3.13 ± 0.7 µg/mL and reduced the IC50 of ZER-HPßCD from 5.08 ± 0.2 µg/mL to 0.49 ± 0.004 µg/mL, indicating that the co-administration enhances the potency and increases the efficacy of ZER and ZER-HPßCD compounds. Acridine orange (AO)/propidium iodide (PI) staining under fluorescence microscopy showed evidence of early apoptosis after 72 h from the co-administration of ZER or ZER-HPßCD with TP5-iRGD peptide in MCF-7 breast cancer cells. The findings of the computational modelling experiment provide novel insights into the ZER interaction with integrin αvß3 in the presence of TP5-iRGD, and this could explain why ZER has better antitumor activities when co-administered with TP5-iRGD peptide.

Antiproliferative and apoptotic activities of 8-prenylnaringenin against human colon cancer cells.

AIMS: The compound 8-prenylnaringenin (8-PN) is a prenylflavonoid that can be isolated from hops and beer and has anti-cancer properties against breast cancer. The aim of this study is to investigate the anti-proliferative and apoptotic activities of 8-PN against human colon cancer HCT-116 cells. MAIN METHODS: Colon cancer HCT-116 cells were treated with 8-PN and subjected to MTT and acridine orange/propidium iodide (AO/PI) staining to investigate the cytotoxicity of 8-PN. Arrest of the cells at different phases of cell cycle was monitored in the presence of 8-PN. Moreover, the apoptotic effects of 8-PN was assessed via annexin V and caspase activity assays and compared to the untreated cells. KEY FINDINGS: The findings showed that 8-PN revealed strong inhibitory effect against HCT-116 cells with an IC50 value of 23.83 ±â€¯2.9 µg/ml after 48 h. However, at similar concentrations and experimental time-points, the compound did not show cytotoxic effect to non-cancerous colon cells (CCD-41). Annexin-V assay indicates that 38.5% and 14.4% of HCT-116 cells had entered early and late stages of apoptosis, respectively after exposure of the cells to 8-PN for 48 h. Caspase activity assay illustrates that apoptosis is activated through both intrinsic and extrinsic pathways. Moreover, flow cytometry cell cycle results indicate that treatment with 8-PN significantly arrested the HCT-116 cells at G0/G1 phase. SIGNIFICANCE: These findings reveal that 8-PN has anti-proliferative activity against HCT-116 colon cancer cells via induction of intrinsic and extrinsic pathway-mediated apoptosis. Further investigations should be carried out to unravel the mechanistic pathways underlying these activities.

Evaluation of Anti-Tumorigenic Effects of Diosmetin against Human Colon Cancer Xenografts in Athymic Nude Mice.

Colon cancer is the third most common type of cancer in the world. Diosmetin (Dis), a natural O-methylated flavone, has been reported to have anti-cancer effects against different types of cancer. Although the mechanisms of action of Dis against several cancer cell lines are well reported, in vivo anti-tumorigenesis properties of this compound are still obscure. Therefore, this study aimed to investigate the anti-tumorigenesis properties of Dis against HCT-116 colon cancer xenografts in nude mice. HCT-116 colon cancer cells were injected in NCr nu/nu nude mice and treatment with Dis was initiated after the tumor volumes reached 100 mm3 and continued for four weeks. On the sacrificing date nude mice treated with 100 mg/kg of Dis showed significant lower tumor volume (264 ± 238.3 mm3) as compared to the untreated group (1428.8 ± 459.6 mm3). Anti-apoptotic Bcl-2 protein was significantly downregulated, while apoptotic protein (Bax) was significantly overexpressed in nude mice treated with 100 mg/kg Dis as compared to untreated mice. In conclusion, our in vivo results indicate that Dis significantly reduces tumor growth rate of HCT-116 colon cancer cells in nude mice at a dose of 100 mg/kg, and has no toxic effects in ICR mice up to 2000 mg/kg.

Investigation into the Molecular Mechanisms underlying the Anti-proliferative and Anti-tumorigenesis activities of Diosmetin against HCT-116 Human Colorectal Cancer.

Diosmetin (Dis) is a bioflavonoid with cytotoxicity properties against variety of cancer cells including hepatocarcinoma, breast and colorectal (CRC) cancer. The exact mechanism by which Dis acts against CRC however, still remains unclear, hence in this study, we investigated the possible molecular mechanisms of Dis in CRC cell line, HCT-116. Here, we monitored the viability of HCT-116 cells in the presence of Dis and investigated the underlying mechanism of Dis against HCT-116 cells at the gene and protein levels using NanoString and proteome profiler array technologies. Findings demonstrated that Dis exhibits greater cytotoxic effects towards HCT-116 CRC cells (IC50 = 3.58 ± 0.58 µg/ml) as compared to the normal colon CCD-841 cells (IC50 = 51.95 ± 0.11 µg/ml). Arrests of the cells in G2/M phase confirms the occurrence of mitotic disruption via Dis. Activation of apoptosis factors such as Fas and Bax at the gene and protein levels along with the release of Cytochrome C from mitochondria and cleavage of Caspase cascades indicate the presence of turbulence as a result of apoptosis induction in Dis-treated cells. Moreover, NF-ƙB translocation was inhibited in Dis-treated cells. Our results indicate that Dis can target HCT-116 cells through the mitotic disruption and apoptosis induction.

An Association Map on the Effect of Flavonoids on the Signaling Pathways in Colorectal Cancer.

Colorectal cancer (CRC) is the third most common type of cancer in the world, causing thousands of deaths annually. Although chemotherapy is known to be an effective treatment to combat colon cancer, it produces severe side effects. Natural products, on the other hand, appear to generate fewer side effects than do chemotherapeutic drugs. Flavonoids are polyphenolic compounds found in various fruits and vegetables known to possess antioxidant activities, and the literature shows that several of these flavonoids have anti-CRC propertiesFlavonoids are classified into five main subclasses: flavonols, flavanones, flavones, flavan-3-ols, and flavanonols. Of these subclasses, the flavanonols have a minimum effect against CRC, whereas the flavones play an important role. The main targets for the inhibitory effect of flavonoids on CRC signaling pathways are caspase; nuclear factor kappa B; mitogen-activated protein kinase/p38; matrix metalloproteinase (MMP)-2, MMP-7, and MMP-9; p53; ß-catenin; cyclin-dependent kinase (CDK)2 and CDK4; and cyclins A, B, D, and E. In this review article, we summarize the in vitro and in vivo studies that have been performed since 2000 on the anti-CRC properties of flavonoids. We also describe the signaling pathways affected by flavonoids that have been found to be involved in CRC. Some flavonoids have the potential to be an effective alternative to chemotherapeutic drugs in the treatment of colon cancer; well-controlled clinical studies should, however, be conducted to support this proposal.