bims-aporos 2018-09-16 papers

Issue of 2018–09–16
four papers selected by
Gavin McStay, Staffordshire University

J Photochem Photobiol B. 2018 Aug 23. pii: S1011-1344(18)30517-7. [Epub ahead of print]188 28-41

Photoactivated [Mn(CO)3Br(μ-bpcpd)]2 induces apoptosis in cancer cells via intrinsic pathway.

Vidhyapriya P, Divya D, Manimaran Bala, Sakthivel N.

Carbon monoxide releasing molecules (CORMs) are organometallic/organic compounds that release carbon monoxide (CO) spontaneously or upon activation. PhotoCORMs are capable of releasing CO on light based activation. This group of molecules is used in photodynamic therapy due to their ability to release CO in a controlled manner. In the present investigation, the release of CO from [Mn(CO)3Br(μ-bpcpd)]2 (MnCORM) upon irradiation at λmax 365 nm was assessed spectrophotometrically using myoglobin assay and confirmed by liquid FT-IR spectroscopic analysis. Further, the cytotoxic potential of MnCORM on normal cells (HEK 293) and cancer cell lines such as lung (A549), cervical (HeLa), breast (MDA MB-231) and colon (HCT-15) was evaluated. The IC50 values of MnCORM were found to be 21.37 ± 1.72, 24.12 ± 1.03, 21.89 ± 0.59 and 13.69 ± 0.91 μM on cervical (HeLa), lung (A549), colon (HCT-15) and breast (MDA MB-231) cancer cells respectively. An inquest into the nature of cell death was confirmed based on the nuclear and cytological examinations, flow cytometric analyses and protein expression studies. The AO/EB dual staining and cytological evaluation of the treated cells revealed that the cell death might be due to apoptosis. The flow cytometric analysis of propidium iodide (PI) stained cells showed a significant amount of sub-G1 hypodiploid cells due to MnCORM treatment. The MnCORM-induced apoptosis was mediated through the generation of reactive oxygen species (ROS), specifically superoxide radicals leading to loss of mitochondrial membrane potential. The intrinsic pathway of apoptosis was elucidated based on the expression studies of pro-apoptotic and apoptotic proteins such as bcl-2, bax, cyt c, cleaved caspase-3, cleaved caspase-9 and cleaved PARP. Due to its innate potential to release CO upon photoactivation and its ability to induce apoptosis via intrinsic pathway, the MnCORM molecule could be exploited for controlled release and photodynamic cancer therapy.

Keywords: Apoptosis; Carbon Monoxide Releasing Molecule; Photoactivation; Targeted Therapy

DOI: https://doi.org/10.1016/j.jphotobiol.2018.08.021

Phytomedicine. 2018 Sep 15. pii: S0944-7113(17)30201-5. [Epub ahead of print]48 152-160

Coptisine-induced apoptosis in human colon cancer cells (HCT-116) is mediated by PI3K/Akt and mitochondrial-associated apoptotic pathway.

Bing Han, Pu Jiang, Zhaoxing Li, Yang Yu, Tao Huang, Xiaoli Ye, Xuegang Li.

BACKGROUND: Colorectal cancer is the third leading cause of cancer-related deaths in the word. Coptisine (COP), an isoquinoline alkaloid derived from Coptis chinensis Franch, possesses a wide variety of pharmacological effects. However, its anti-proliferative effect on colon cancer is not fully elucidated. In the present study, we aimed to ascertain whether COP inhibits HCT-116 cell growth and to further explore the molecular mechanism in vitro and in vivo.
METHODS: Cell viability was determined by MTT assay. Cell migration was detected using wound healing assay. Apoptosis, mitochondrial membrane potential (Δψm) and reactive oxygen species (ROS) was analysis via flow cytometry. Hoechst 33342 was used for morphology observation. The expression levels of proteins related to mitochondrial-mediated apoptotic pathway were detected by western blotting. In addition, the antitumor ability of COP was further measured in athymic nude mice.
RESULTS: COP significantly decreased cell viability and migration in HCT-116 cells. Flow cytometry and Hoechst 33342 analysis confirmed that COP suppressed cell proliferation by inducing apoptosis. COP decreased Δψm dose-dependently and induced intracellular ROS production time-dependently. Western blotting showed that COP activated mitochondrial-associated apoptosis by down-regulating Bcl-2, Bcl-XL, pro-caspase 3, XIAP level and up-regulating Bax, Bad, cytochrome c, Apaf-1, AIF and cleaved caspase-3 expression. In addition, COP also attenuated PI3K/Akt signaling pathway. In vivo study showed that 150 mg/kg COP significantly delayed the tumor development in BALB/c nude mice. Immunohistochemical analysis also confirmed the activated apoptosis in tumor tissue.
CONCLUSION: The results demonstrated that COP induces apoptosis in HCT-116 cells through PI3K/Akt and mitochondrial-associated apoptotic pathway. Our findings suggest that COP has potential to be a therapeutic candidate for colon cancer patients.

Keywords: Apoptosis; Coptisine; Mitochondria; PI3K/Akt; ROS

DOI: https://doi.org/10.1016/j.phymed.2017.12.027

Phytomedicine. 2018 Sep 15. pii: S0944-7113(17)30190-3. [Epub ahead of print]48 112-119

Cytotoxicity of epunctanone and four other phytochemicals isolated from the medicinal plants Garcinia epunctata and Ptycholobium contortum towards multi-factorial drug resistant cancer cells.

Armelle T Mbaveng, Ghislain W Fotso, Dominique Ngnintedo, Victor Kuete, Bonaventure T Ngadjui, Felix Keumedjio, Kerstin Andrae-Marobela, Thomas Efferth.

INTRODUCTION: Resistance of cancer cells is a serious impediment to chemotherapy and several phytochemicals are active against multi-drug resistant (MDR) phenotypes. The cytotoxicity of five naturally occurring compounds: betulin (1), mundulea lactone (2), seputhecarpan A (3), seputheisoflavone (4) and epunctanone (5) was evaluated on a panel of 9 cancer cell lines including various sensitive and drug-resistant cell lines. The modes of action of compound 5 were further investigated.
METHODS: The resazurin reduction assay was used to evaluate cytotoxicity of samples and ferroptotic cell death induced by compound 5; caspase-Glo assay was used to detect the activation of caspases in CCRF-CEM leukemia cells treated with compound 5. Flow cytometry was used for cell cycle analysis in CCRF-CEM cells treated with compound 5, as well as detection of apoptotic cells by annexin V/PI staining, analysis of mitochondrial membrane potential (MMP) and measurement of reactive oxygen species (ROS).
RESULTS: Compounds 1-5 displayed cytotoxic effects in the 9 studied cancer cell lines with IC50 values below 70 µM. The IC50 values varied from 8.20 µM (in HCT116 (p53-/-) colon cancer cells) to 35.10 µM (against HepG2 hepatocarcinoma cells) for 1, from 8.84 µM (in CEM/ADR5000 leukemia cells) to 48.99 µM (in MDA-MB-231 breast adenocarcinoma cells) for 2, from 12.17 µM (in CEM/ADR5000 cells) to 65.08 µM (in MDA-MB-231 cells) for 3, from 23.80 µM (in U87MG.ΔEGFR glioblastoma cells) to 68.66 µM (in HCT116 (p53-/-) cells) for 4, from 4.84 µM (in HCT116 (p53-/-) cells) to 13.12 µM (in HepG2 cells) for 5 and from 0.02 µM (against CCRF-CEM cells) to 122.96 µM (in CEM/ADR5000 cells) for doxorubicin. Compound 5 induced apoptosis in CCRF-CEM cells through alteration of MMP and increase in ROS production. In addition to apoptosis, ferroptosis was also identified as another mode of cell death induced by epunctanone.
CONCLUSIONS: Compounds 1-5 are valuable cytotoxic compounds that could be used to combat MDR cancer cells. Benzophenoe 5 is the most active molecule and deserve more investigations to develop new anticancer drugs.

Keywords: Apoptosis; Benzophenone; Cytotoxicity; Ferroptosis; Multi-drug resistance; Phytochemicals

DOI: https://doi.org/10.1016/j.phymed.2017.12.016

Apoptosis. 2018 Sep 08.

Molecular targeting of breast and colon cancer cells by PAR1 mediated apoptosis through a novel pro-apoptotic peptide.

Tanusree Ray, Dwiprohi Kar, Ananda Pal, Shravanti Mukherjee, Chandrima Das, Amit Pal.

A novel activating peptide was designed and synthesized from V. cholerae hemagglutinine protease (HAP) mediated cleavage site of mouse PAR1. The peptide "PFISED" interacts with PAR1 in a new site which is different from its thrombin mediated conventional activation site and induced a series of new downstream signaling pathways. The peptide showed apoptosis in human and mouse breast (MCF-7 and EAC) and colon (HT29 and CT26) cancer cells where as in the same peptide concentration in normal human breast epithelial cells (MCF-10A), normal human fibroblast cells (MRC-5), normal mouse peritoneal macrophage cells and normal mouse breast and colon tissues did not show any effect. Treatment with this peptide enhanced the survival kinetics of EAC induced mice. The peptide mediated apoptosis was inhibited in presence of PAR1 inhibitor and was significantly reduced in si-PAR1 treated cells that indicate the activating peptide "PFISED" induced PAR1 mediated apoptosis of colon and breast cancer cells. This peptide induced over expression and activation of PAR1 and its downstream MAP kinase and NFκB signaling pathways. These signaling pathways enhanced the cellular ROS level to kill malignant cells. We report a novel pro-apoptotic peptide which can selectively kill malignant cells via its specific target receptor PAR1 which is over expressed in the malignant cells and can be used as a molecular target therapy for cancer treatment.

Keywords: Apoptosis; PAR1; Pro-apoptotic peptide; Targeted therapy

DOI: https://doi.org/10.1007/s10495-018-1485-4