Nik Soriani Yaacob

Anticancer activity of a sub-fraction of dichloromethane extract of Strobilanthes crispus on human breast and prostate cancer cells in vitro

BackgroundThe leaves of Strobilanthes crispus (S. crispus) which is native to the regions of Madagascar to the Malay Archipelago, are used in folk medicine for their antidiabetic, diuretic, anticancer and blood pressure lowering properties. Crude extracts of this plant have been found to be cytotoxic to human cancer cell lines and protective against chemically-induced hepatocarcinogenesis in rats. In this study, the cytotoxicity of various sub-fractions of dichloromethane extract isolated from the leaves of S. crispus was determined and the anticancer activity of one of the bioactive sub-fractions, SC/D-F9, was further analysed in breast and prostate cancer cell lines.MethodsThe dichloromethane extract of S. crispus was chromatographed on silica gel by flash column chromatography. The ability of the various sub-fractions obtained to induce cell death of MCF-7, MDA-MB-231, PC-3 and DU-145 cell lines was determined using the LDH assay. The dose-response effect and the EC50 values of the active sub-fraction, SC/D-F9, were determined. Apoptosis was detected using Annexin V antibody and propidium iodide staining and analysed by fluorescence microscopy and flow cytometry, while caspase 3/7 activity was detected using FLICA caspase inhibitor and analysed by fluorescence microscopy.ResultsSelected sub-fractions of the dichloromethane extract induced death of MCF-7, MDA-MB-231, PC-3 and DU-145 cells. The sub-fraction SC/D-F9, consistently killed breast and prostate cancer cell lines with low EC50 values but is non-cytotoxic to the normal breast epithelial cell line, MCF-10A. SC/D-F9 displayed relatively higher cytotoxicity compared to tamoxifen, paclitaxel, docetaxel and doxorubicin. Cell death induced by SC/D-F9 occurred via apoptosis with the involvement of caspase 3 and/or 7.ConclusionsA dichloromethane sub-fraction of S. crispus displayed potent anticancer activities in vitro that can be further exploited for the development of a potential therapeutic anticancer agent.

In vitro biocompatibility of chitosan porous skin regenerating templates (PSRTs) using primary human skin keratinocytes.

Biopolymer chitosan (beta-1,4-d-glucosamine) comprises the copolymer mixture of N-acetylglucosamine and glucosamine. The natural biocompatibility and biodegradability of chitosan have recently highlighted its potential use for applications in wound management. Chemical and physical modifications of chitosan influence its biocompatibility and biodegradability, but it is unknown as to what degree. Hence, the biocompatibility of the chitosan porous skin regenerating templates (PSRT 82, 87 and 108) was determined using an in vitro toxicology model at the cellular and molecular level on primary normal human epidermal keratinocytes (pNHEK). Cytocompatibility was accessed by using a 3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl tetrazolium bromide (MTT) assay from 24 to 72h. To assess the genotoxicity of the PSRTs, DNA damage to the pNHEK was evaluated by using the Comet assay following direct contact with the various PSRTs. Furthermore, the skin pro-inflammatory cytokines TNF-alpha and IL-8 were examined to evaluate the tendency of the PSRTs to provoke inflammatory responses. All PSRTs were found to be cytocompatible, but only PSRT 108 was capable of stimulating cell proliferation. While all of the PSRTs showed some DNA damage, PSRT 108 showed the least DNA damage followed by PSRT 87 and 82. PSRT 87 and 82 induced a higher secretion of TNF-alpha and IL-8 in the pNHEK cultures than did PSRT 108. Hence, based on our experiments, PSRT 108 is the most biocompatible wound dressing of the three tested.

Tualang Honey Promotes Apoptotic Cell Death Induced by Tamoxifen in Breast Cancer Cell Lines

Tualang honey (TH) is rich in flavonoids and phenolic acids and has significant anticancer activity against breast cancer cells comparable to the effect of tamoxifen (TAM), in vitro. The current study evaluated the effects of TH when used in combination with TAM on MCF-7 and MDA-MB-231 cells. We observed that TH promoted the anticancer activity of TAM in both the estrogen receptor-(ER-)responsive and ER-nonresponsive human breast cancer cell lines. Flow cytometric analyses indicated accelerated apoptosis especially in MDA-MB-231 cells and with the involvement of caspase-3/7, -8 and -9 activation as shown by fluorescence microscopy. Depolarization of the mitochondrial membrane was also increased in both cell lines when TH was used in combination with TAM compared to TAM treatment alone. TH may therefore be a potential adjuvant to be used with TAM for reducing the dose of TAM, hence, reducing TAM-induced adverse effects.

Tualang honey protects keratinocytes from ultraviolet radiation-induced inflammation and DNA damage.

Malaysian tualang honey possesses strong antioxidant and anti‐inflammatory properties. Here, we evaluated the effect of tualang honey on early biomarkers of photocarcinogenesis employing PAM212 mouse keratinocyte cell line. Keratinocytes were treated with tualang honey (1.0%, v/v) before a single UVB (150 mJ cm−2) irradiation. We found that the treatment of tualang honey inhibited UVB‐induced DNA damage, and enhanced repair of UVB‐mediated formation of cyclobutane pyrimidine dimers and 8‐oxo‐7,8‐dihydro‐2′‐deoxyguanosine. Treatment of tualang honey inhibited UVB‐induced nuclear translocation of NF‐κB and degradation of IκBα in murine keratinocyte cell line. The treatment of tualang honey also inhibited UVB‐induced inflammatory cytokines and inducible nitric oxide synthase protein expression. Furthermore, the treatment of tualang honey inhibited UVB‐induced COX‐2 expression and PGE2 production. Taken together, we provide evidence that the treatment of tualang honey to keratinocytes affords substantial protection from the adverse effects of UVB radiation via modulation in early biomarkers of photocarcinogenesis and provide suggestion for its photochemopreventive potential.

Proliferation of keratinocytes induced by adipose-derived stem cells on a chitosan scaffold and its role in wound healing, a review.

In the field of tissue engineering and reconstruction, the development of efficient biomaterial is in high demand to achieve uncomplicated wound healing. Chronic wounds and excessive scarring are the major complications of tissue repair and, as this inadequate healing continues to increase, novel therapies and treatments for dysfunctional skin repair and reconstruction are important. This paper reviews the various aspects of the complications related to wound healing and focuses on chitosan because of its unique function in accelerating wound healing. The proliferation of keratinocytes is essential for wound closure, and adipose-derived stem cells play a significant role in wound healing. Thus, chitosan in combination with keratinocytes and adipose-derived stem cells may act as a vehicle for delivering cells, which would increase the proliferation of keratinocytes and help complete recovery from injuries.

The flavonoid fisetin as an anticancer agent targeting the growth signaling pathways

Epidemiological studies show that consumption of diets rich in fruits and vegetables is associated with lower risks of cancer. This evidence has kindled interest into research on bioactive food components and has till date resulted in the identification of many compounds with cancer preventive and therapeutic potential. Among such compounds is fisetin (3,7,3,4-tetrahydroxyflavone), a flavonol that is commonly found in many fruits and vegetables such as apples, persimmons, grapes, kiwis, strawberries, onions and cucumbers. Fisetin has been shown to inhibit or retard the growth of various cancer cells in culture and implanted tumors in vivo. Fisetin targets many components of intracellular signaling pathways including regulators of cell survival and apoptosis, tumor angiogenic and metastatic switches by modulating a distinct set of upstream kinases, transcription factors and their regulators. Current evidence supports the idea that fisetin is a promising agent for cancer treatment. This review summarizes reported anticancer effects of fisetin, and re-emphasizes its potential therapeutic role in the treatment of cancer.

Synergistic anticancer effects of a bioactive subfraction of Strobilanthes crispus and tamoxifen on MCF-7 and MDA-MB-231 human breast cancer cell lines

BackgroundDevelopment of tumour resistance to chemotherapeutic drugs and concerns over their toxic effects has led to the increased use of medicinal herbs or natural products by cancer patients. Strobilanthes crispus is a traditional remedy for many ailments including cancer. Its purported anticancer effects have led to the commercialization of the plant leaves as medicinal herbal tea, although the scientific basis for its use has not been established. We previously reported that a bioactive subfraction of Strobilanthes crispus leaves (SCS) exhibit potent cytotoxic activity against human breast cancer cell lines. The current study investigates the effect of this subfraction on cell death activities induced by the antiestrogen drug, tamoxifen, in estrogen receptor-responsive and nonresponsive breast cancer cells.MethodsCytotoxic activity of SCS and tamoxifen in MCF-7 and MDA-MB-231 human breast cancer cells was determined using lactate dehydrogenase release assay and synergism was evaluated using the CalcuSyn software. Apoptosis was quantified by flow cytometry following Annexin V and propidium iodide staining. Cells were also stained with JC-1 dye to determine changes in the mitochondrial membrane potential. Fluorescence imaging using FAM-FLICA assay detects caspase-8 and caspase-9 activities. DNA damage in the non-malignant breast epithelial cell line, MCF-10A, was evaluated using Comet assay.ResultsThe combined SCS and tamoxifen treatment displayed strong synergistic inhibition of MCF-7 and MDA-MB-231 cell growth at low doses of the antiestrogen. SCS further promoted the tamoxifen-induced apoptosis that was associated with modulation of mitochondrial membrane potential and activation of caspase-8 and caspase-9, suggesting the involvement of intrinsic and extrinsic signaling pathways. Interestingly, the non-malignant MCF-10A cells displayed no cytotoxicity or DNA damage when treated with either SCS or SCS-tamoxifen combination.ConclusionsThe combined use of SCS and lower tamoxifen dose could potentially reduce the side effects/toxicity of the drug. However, further studies are needed to determine the effectiveness and safety of the combination treatment in vivo.

Comparison of cytotoxicity and genotoxicity of 4-hydroxytamoxifen in combination with Tualang honey in MCF-7 and MCF-10A cells

BackgroundThe Malaysian Tualang honey (TH) is not only cytotoxic to human breast cancer cell lines but it has recently been reported to promote the anticancer activity induced by tamoxifen in MCF-7 and MDA-MB-231 cells suggesting its potential as an adjuvant for the chemotherapeutic agent. However, tamoxifen produces adverse effects that could be due to its ability to induce cellular DNA damage. Therefore, the study is undertaken to determine the possible modulation of the activity of 4-hydroxytamoxifen (OHT), an active metabolite of tamoxifen, by TH in non-cancerous epithelial cell line, MCF-10A, in comparison with MCF-7 cells.MethodsMCF-7 and MCF-10A cells were treated with TH, OHT or the combination of both and cytotoxicity and antiproliferative activity were determined using LDH and MTT assays, respectively. The effect on cellular DNA integrity was analysed by comet assay and the expression of DNA repair enzymes was determined by Western blotting.ResultsOHT exposure was cytotoxic to both cell lines whereas TH was cytotoxic to MCF-7 cells only. TH also significantly decreased the cytotoxic effect of OHT in MCF-10A but not in MCF-7 cells. TH induced proliferation of MCF10A cells but OHT caused growth inhibition that was abrogated by the concomitant treatment with TH. While TH enhanced the OHT-induced DNA damage in the cancer cells, it dampened the genotoxic effect of OHT in the non-cancerous cells. This was supported by the increased expression of DNA repair proteins, Ku70 and Ku80, in MCF-10A cells by TH.ConclusionThe findings indicate that TH could afford protection of non-cancerous cells from the toxic effects of tamoxifen by increasing the efficiency of DNA repair mechanism in these cells.

Modulation of cell growth and PPARγ expression in human colorectal cancer cell lines by ciglitazone

Studies have shown that ligand activation of peroxisome proliferator-activated receptor gamma (PPARgamma) can induce differentiation and inhibit proliferation of several cancer cells. The present study was performed to investigate the effects of the PPARgamma ligand, ciglitazone, and the involvement of PPARgamma in modulating the growth of human colorectal cancer cells. Lactate dehydrogenase release assay showed that ciglitazone potently inhibited HT-29 (well-differentiated) and COLO-205 (poorly differentiated) colorectal adenocarcinoma cell growth. Measurement of apoptosis by flow cytometry using a fluorescein-conjugated monoclonal antibody against cytokeratin 18 revealed a high induction of apoptosis by ciglitazone in a time-dependent fashion. The expression of PPARgamma1 but not PPARgamma2 mRNA was significantly downregulated as measured by real-time quantitative PCR, and the PPARgamma protein levels were decreased as determined by Western blot analysis. We conclude that ciglitazone treatment suppressed colon cancer cell growth via induction of apoptosis. However, the anticancer effects of ciglitazone may not depend solely on PPARgamma activation.

The Modulation of PPARγ1 and PPARγ2 mRNA Expression by Ciglitazone in CD3/CD28-Activated Naïve and Memory CD4+ T Cells

Given their roles in immune regulation, the expression of the nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ) 1 and 2 isoforms was investigated in human naïve (CD45RA+) and memory (CD45RO+) CD4+ T cells. Stimulation of both types of cells via the CD3/CD28 pathway resulted in high expression of both PPARγ receptors as measured by real-time PCR. Treatment with the PPARγ agonist, ciglitazone, increased PPARγ1 expression but decreased PPARγ2 expression in stimulated naïve and memory cells. Furthermore, when present, the magnitude of both PPARγ receptors expression was lower in naïve cells, perhaps suggesting a lower regulatory control of these cells. Similar profiles of selected proinflammatory cytokines were expressed by the two cell types following stimulation. The induction of PPARγ1 and suppression of PPARγ2 expressions in naïve and memory CD4+ T cells in the presence of ciglitazone suggest that the PPARγ subtypes may have different roles in the regulation of T-cell function.