Mrudul Pravinbhai Vekaria

Therapeutics against breast cancer is a major research field, due to inefficiency or partial efficiency of existing therapeutics. An urge to discover better therapeutics always persists. Our objective is to study salicin against breast cancer cells, in order to find its therapeutic properties. To study the effect of salicin on breast cancer cells, we performed MTT assay on MCF-7 (hormone positive) and MDA-MB-231 (triple negative) breast cancer cell lines, we did brine shrimp lethality test (BSLT) assay to see the lethal effects of salicin. By the help of bioinformatics we tried to locate the targets that delineate salicin activity. Salicin was docked with estrogen receptor (ER), progesterone receptor (PR) and Human epidermal growth factor receptor 2 (HER2) to study its binding efficiency and possible targets of salicin. Salicin remarkably reduces cell viability both in MCF-7 and MDA-MB-231, along with being lethal to brine shrimps. These results together opine that salicin can be an effective therapeutics against breast cancer cells. The mechanism of action of salicin is probably through ER, PR and HER2 receptors because it can efficiently bind these receptors with minimum energy required for binding. This explains that salicin can easily bind to these receptors. These results together opine that salicin can be an effective therapeutics against breast cancer cells. The mechanism of action of salicin is probably through ER, PR and HER2 receptors because it can efficiently bind these receptors with minimum binding energy. ER, PR and HER2 are major reasons behind the disease pathogenicity depending on the type of breast cancer. According to our results salicin may either induce apoptosis or reduce cellular mitosis both via P53 dependent and independent pathway, which makes salicin a good choice of both hormone positive and negative breast cancer cells. 73 * Corresponding Author: Mrudual Pravinbai Vekaria R.K University, School of Pharmacy, Bhavnagar Highway, Tramba, Gujarat 360020, India. Email Id: vekaria_mrudul@yahoo.com Mrudual Pravinbai Vekaria et.al., Salicin: a promising ER, PR and HER2 binding molecule Published online in http://ijam.co.in ISSN No: 0976-5921 6). Mechanism underlying salicins anti-inflammatory effect was reported in RAW264.7 cells against lipopolysaccharides (LPS) in mouse models where it suppressed the expression of pro-inflammatory cytokines (TNF-α, IL-1b, IL-6, and IL-10) and the activation of NF-κB (7). Administration of salicin suppresses edema and mucosal damage by ameliorating inflammatory response in mouse models of dextran sulfate sodium (DSS)-induced colitis (8). It is quite motivating that willow bark extract has tremendous healing property and other previous studies led us to investigate whether salicin plays a beneficial role in breast cancer and reveal the underlying molecular mechanism of action against breast cancer. Along with anti-inflammation and pain reliving activity, acetylsalicylic acid (ASA, CAS 50-78-2), it has been shown to function same as synthetic non-steroidal antiinflammatory drugs (NSAIDs) and exert antiproliferative effects and to induce pro-apoptosis in a variety of cell lines, e.g., colon, stomach, and prostate cancer cells. These activity of salicin is least explored against breast cancer cell lines or tumors. About 80% of all breast cancers are “ERpositive and 65% are “PR-positive. ” These cancer cells grow in response to the hormone estrogen or progesterone. Tumors that are ER/PR-positive are much more likely to respond to hormone therapy than tumors that are ER/PR-negative. Medications include Tamoxifen, which blocks hormone receptors by preventing the hormones from binding to them. Aromatase inhibitors such as anastrozole, exemestane, and letrozole are used to treat hormone receptor positive breast cancer in menopausal women to stop estrogen production. Fulvestrant and Toremifene are used to block and damage estrogen receptors and is sometimes used to treat metastatic breast cancer. CDK 4/6 inhibitors such as abemaciclib, palbociclib and ribociclib are sometimes used with aromatase inhibitors or the hormone therapy fulvestrant. Despite of these therapeutic interventions cancer are not curable for 100% of the population and moreover thee medications carry harmful side effects, for example tamoxifen may induce endometrial cancer. Since, it hampers the normal physiology of both cancer and normal cells (9). Second major protein involved or causes breast cancer is Human epidermal growth factor receptor-2 positive; also known as ERBB2 (HER2) and its relatives HER1 epidermal growth factor receptor (EGFR), HER3 and HER4 are the member of HER family of receptor tyrosine kinases. Activation of this family of receptor tyrosine kinase triggers a rich network of signaling pathways that control normal cells growth including differentiation, motility and adhesion. Alteration of the HER2 oncogene was first studied in breast carcinoma. Involvement of HER2 as a cause of human cell transformation needs further research and investigation. Overexpression of the HER2 oncogene in human breast cancers is associated with a more aggressive form of disease. In approximately 20% of breast cancers, the cells express a huge amount HER2 which makes them aggressive and fast-growing. In HER2-positive breast cancers, the targeted drug trastuzumab dramatically reduces the risk of the cancer recurrence. Trastuzumab along with chemotherapy is given after surgery to metastatic breast cancer patients. It can also be used for early-stage breast cancer, but it carries a small but real risk of heart damage and possible lung damage. Thus finding an alternative medication with no such side effect is still a global need (10) The third type of breast cancer is the Triplenegative breast cancer (TNBC) that lack or do not express ER, PR, or HER2 genes. This type of cancers represents challenging clinical condition because they do not respond either to endocrine therapy or other available targeted drugs. They possess metastatic features similar to other breast cancer types but are associated with shorter median time to relapse and death. 10 to 20% of breast cancer cases are “triple negative and mostly carries BRCA1 mutation. TNBC are often treated with surgery, chemotherapy, and radiation and Olaparib and talazoparip which blocks PARP can be used in BRCA mutation who have metastatic HER2-negative breast cancer. Atezolizumab, an immunotherapy drug in combination with the chemotherapy nab-paclitaxel blocks a protein called PD-L1 are used in certain TNBC. The current medical regimen clarifies that a few drugs with a very few targets are present in the market, and most of them are used in combination with chemotherapy. Chemotherapy being one of the harsh treatment methods generally leaves the patient in a physiologically lost condition. Chemotherapy kills both normal and cancer cells, thus carries severe side effects (11, 12). In the current study we used both bioinformatics and in vitro cell culture the access its ER, PR and HER2 binding property and to investigate its effect on hormone receptor positive and negative breast cancer cell line. In the current scenario of adversely affecting drugs or limited drugs, Salicin could be a promising option with multiple targets that it can influence, some of these targets which are directly or indirectly associated with initiation and or progression of the disease. Materials and Methods Chemicals and Reagents Salicin (Yucca Enterprises Wadala, Mumbai), MCF-7 cell line (NCCS, Pune), MDA-MB-231 cell line (NCCS, Pune), Amazon.in (e-market) as capsules, RPMI medium with 10 % Fetal bovine serum (FBS) (HiMedia) supplemented with 1% anti-biotic-antimycotic solution (Sigma-Aldrich), 96 well plate (Thermo Fisher Scientific), Biosafety cabinet level II, MTT solution (HiMedia), Multiskan GO microplate spectrophotometer and Ligplot+ software version 1.4. 5 (Roman Laskowski, 2009).