CYTOTOXIC EFFECT OF TAXOL AND VITAMIN E SUCCINATE COMBINATION IN COMPARISON WITH TAXOL ALONE ON MCF-7 BREAST CANCER CELL CULTURE BY MTT ASSAY
The University of London Metropolitan University,
Breast cancer is widely spreaded type of cancer in women and responsible for high number of cancer death in women. Taxol has been already approved to be used for breast cancer by FDA. There have been several studies on the anti tumor activities of Vitamin E Succinate (VES) as complementary and alternative medicine. In present study, we investigated the cytotoxic effect of taxol-VES combination on MCF-7 breast cancer cell lines in comparison with taxol alone. MCF-7 cells are preffered because of higher sensitivity to estogens. MCF-7 cells were sub cultured in according to specifications of aseptic conditions by incubating at 37οC and 5%CO2. Cells were seeded in 24 well plate with culture medium and different concentration of different drug regimen ( taxol alone, VES alone, taxol-VES combination) for 72hrs. Cell viability can be checked by MTT cell viability assay. MTT assay uses a MTT dye which acts as a substrate for viable cell reductase enzyme. This enzyme reduces MTT yellow dye to purple colour formazan which is in proportional to viable cell eventually. The intensity of purple colour was measured by measuring absorbances at 570nM using spectrophotometer. The results of the study were plotted as %cell viability Vs concentration for each of three drug regimen. IC50 values for each drugs were calculated. Graphical and statistical analysis of results concluded that taxol-MCF combination has more inhibitory effect on MCF-7 breast cancer cell lines when treated for 72hrs in comparison with taxol alone and statistical analysis had concluded that results were significant enough to accept clinically to use in stratagic breast cancer therapy management.
Reference Id: PHARMATUTOR-ART-1268
Breast cancer is the second leading cause of cancer death exceeded only by lung cancer in women(Weiss M, 2008(a)).Breast cancer is an uncontrolled growth of breast cells. It is a result of mutations, or abnormal changes, in the genes responsible for healthy growth regulation of each cells. These changed cells gain the ability to keep dividing without control or order, producing more cells just like it and forming a tumour (Breast cancer research UK, 2009). A tumour can be benign (not dangerous to health) or malignant (has the potential to be dangerous). Malignant tumours are cancerous and if they left unchecked, they spread throughout to body (Wikipedia, 2010). Usually breast cancer either begins in the cells of the lobules which produces milk, or the ducts, the passage that passes milk from the lobules to the nipple (Merk Manual, 2010). Breast cancer is being screened by mammogram technology. Routine mamographic screening is an accepted standard for early detection of breast cancer detection (Weiss M, 2008(b)). The study of large groups of related individuals led to the identification of several breast cancer susceptibility genes, including BRCA1, BRCA2. Mutations in these genes account for all hereditary breast cancers (NCI, 2009). Now-a-days, there are many treatment options available for breast cancer like Surgery ( Lumpectomy, Mastectomy ) Radiation Therapy, Hormonal Therapy ( aromatase inhibitors, selective eastrogen receptor modulators, and estrogen receptor down regulators), targeted therapies (trastuzumab-monoclonal antibody), and at last but most widely used is chemotherapy and combination therapy of all of above (Breast cancer UK, 2009(b))Chemotherapy treatment uses medicine to weaken and destroy cancer cells in the body. Chemotherapy is used to treat early-stage invasive breast cancer to get rid of any cancer cells that may be left behind after surgery and advanced-stage breast cancer. In many cases, a combination of two or more medicines will be used as chemotherapy treatment for breast cancer. These Combinations are known as chemotherapy regimens. There is a list of drugs that are being used in chemotherapy. Standard chemotherapy regimens include Adriamycin and taxol (AT), Cytoxan, methotrexate and fluorouracil (CMF), and Flurouracil,adriamycin and cytoxan etc (Breast cancer.org, 2009) but out from these standard regimens the combination of my interest is Taxol and Vitamin-E succinate which I will discuss in later part of this study.
Paclitaxel (Taxol) is obtained from dried bark of plant Taxus brevifolia (Pacific yew tree) which is mound mostly in N.America, china, and Europe (21cecpharm, 2008) The twig of which is shown in figure 1.
( Figure1:- Twig of Plant of Taxus brevifolia ) ( Wikipedia paclitaxel, 2010)
Taxol is in top of all anticancer drugs in the battle of we humans against cancer as it constitutes about 22 percentage of all major cancer chemotherapy drugs on the world market (chemocare, 2005). It is approved by the FDA to treat ovarian camcer in 1992 , breast cancer in 1994, and AIDS-related Kaposi sarcoma(National Cancer Institute, 2008). It is best to be used together with drug called cisplatin to treat advanced ovarian cancer and breast cancer. BMS (Bristol Mayers Squibb) is the pioneer for the development of taxol to its clinical use. BMS and Ivax have made billions of dollars with taxol. (National Cancer Institute,2008). It is clear colourless fluid that is given as as a chemotherapy infusion in early stage and metastatic breast cancer as a single or multiple drug regimen. Invivo and invitro study shows that B-subunit of microtubule heterodimer act as a target site for paclitaxel. Microtubules are a kind of cell skeleton and make up the organs of movement. However,when cell division is about to take place microtubules depolymerise back to tubulin and repolymerise to form the spindle of cell division. This spindle formation is necessary process for a cell to divide into two. In 1979, susan horwitz showed that taxol stimulates the formation of microtubules and prevents their depolymerization (Jordan M and Wilson L., April 2004) which is shown in figure2.
(Figure-2 Mechanism of action of Taxol, as it binds with microtubule it prevents its depolymerization) (Jordan M and Wilson L., April 2004)
So, it interrupts spindle formation process and eventually cell division process at the G2/M phase (Jordan M and Wilson L., april 2004)(Kumar N, 1981). Thus, it acts as an anticancer agent. The adverse drug reactions associated with taxol are peripheral neuropathy, mucositis, alopecia, neutropenia, cardiotoxicity, diarrhoea, and hypotension, reduction in WBC (Wikipedia paclitaxel, 2010). Paclitaxel undergoes transesterification in methanol, and it hydrolyzes in aqueous solutions. It is available as a white powder melting point of it is 213ºC. It is solubilize in eathanol and DMSO. The storage temperature is 2-8ºC. The price for paclitaxel powder in UK is 23