ISSN 2320-5407 International Journal of Advanced Research (2015), Volume 3, Issue 1, 834-846 834 Journal homepage: http://www.journalijar.com INTERNATIONAL JOURNAL OF ADVANCED RESEARCH RESEARCH ARTICLE Antitumor activity of doxycycline in HepG-2 cells Mohammed. A. F. Elewa 1, 2* , Mohammed M. Al-Gayyar 2 , Mona F. Schaalan 1 , Mamdouh M. El-Shishtawy 2 1. Dept. of Pharmacy Practice and Clinical Pharmacy, Faculty of Pharmacy, Misr International University, Cairo, 18111, Egypt. 2. Dept. of Biochemistry, Faculty of Pharmacy, Mansoura University, Mansoura, 35516, Egypt. Manuscript Info Abstract Manuscript History: Received: 15 November 2014 Final Accepted: 22 December 2014 Published Online: January 2015 Key words: MMP-9, HSPGs, Fascin, Oxidative stress, Doxycyline, Caspase-3. *Corresponding Author Mohammed. A. F. Elewa Hepatocellular carcinoma (HCC) is a major health problem worldwide. While considerable advances have been made in diagnosis and treatment of HCC, it is still associated with high rate of mortality and poor prognosis, even with therapies that are considered potentially curative. The current study sought to evaluate the anti-tumor/cytotoxic activity of doxycycline in HepG2 cells. Following 48-hr treatments with increasing concentrations of doxycycline, HepG2 cell survival was measured using MTT and lactate dehydrogenase (LDH) assays. Matrix metalloproteinase-9 (MMP-9), heparan sulfate proteoglycans (HSPGs), and Fascin levels were assessed via ELISA. In addition, indicators of potential induction of apoptosis and anti-oxidant activity of the drug were assessed via measures of cell caspase-3 activity and both superoxide anion production and superoxide dismutase activity, respectively. The results indicate that treatment of the HepG2 cells with doxycycline caused reductions in cell survival in a dose-related manner. In addition, it was seen that doxycycline was able to stimulate cellular apoptosis (measured by caspase-3 activity) in these cells. In conclusion, doxycycline proved promising cytotoxic/antitumor activity and opens, thereby, a new horizon against vascular migration ability of the tumor cells. Copy Right, IJAR, 2015,. All rights reserved 1. Introduction Hepatocellular carcinoma (HCC) is a major health problem worldwide; it is the fifth most common cancer and the third most common cause of cancer-related death (Hashiguchi et al., 2013). Tumor invasion is a complex biological process that involves the loss of cell–cell contact, followed by detachment from the primary tumor, active cell migration, invasion, and infiltration in the surrounding tissue. The mechanisms underlying local invasion and distant metastasis are still unclear (Bao et al., 2013). Thus, understanding the mechanisms involved in the development of HCC invasion and metastasis is crucial to improve future treatment strategies and prognosis. Heparan sulfate proteoglycans (HSPGs) are present on the cell surface of most cells and are major elements of the extracellular matrix (ECM) (Bishop et al., 2007). HSPGs comprise core proteins covalently attached to one or more sugar chains called heparan sulfate chains. The ability of HSPGs to bind to diverse protein ligands, including growth factors, proteases, matrix proteins, and cell adhesion molecules, facilitates a multitude of structural and signaling functions (Iozzo, 2001). HSPGs also play an important defensive role against tumor cell invasion. It has been shown that the activities of HSPGs-degrading enzymes were noticeably higher in invasive cancer cells than in cells with less invasive potentials (Toyoshima and Nakajima, 1999). Numerous clinical and experimental studies have demonstrated that elevated levels of matrix metalloproteinases (MMPs) are associated with increased tumor growth, cancer progression, and metastasis, and shortened survival in patients. Among the various MMPs, MMP-9 (gelatinase B) has been postulated to play a