Nasopharyngeal carcinoma (NPC), a disease with distinct ethnic and geographic distribution, is common in Southern China, North Africa and South East Asia including Malaysia [
1]. Approximately 95% of NPC cases [
2] are strongly associated with latent infection of the Epstein-Barr virus (EBV).
Radiotherapy is the primary modality of treatment for NPC. In addition, concurrent chemotherapy with cisplatin and 5-fluorouracil is used. High survival rates are reported for stage 1 and stage 2 diseases [
2]. Unfortunately, even with combined radiation and chemotherapy treatment, the rate of disease relapse is as high as 82% [
2] and patients with locoregionally advanced disease, which most patients present, will eventually fail with distant metastases [
3]. Improving outcomes are not without side-effects and are often linked to toxicity [
4]. In addition, drug resistance may hamper the efficacy of these anticancer drugs. Potential NPC chemotherapy
via natural product administration may circumvent some of these chemical- and radiation-associated toxicities.
Quercetin (3,3’,4’,5,7-pentahydroxyflavone) is a polyphenolic flavonoid widely distributed in fruits and vegetables, including apple, blueberries, broccoli, grape, leek, lettuce, onion and tomato. Being in a class of integral flavonoids common in our diet, it should exert low toxicity [
5]. Quercetin may act on multiple targets. The mechanisms responsible for the cancer-preventive effects of quercetin and other flavonoids are attributed to their anti-oxidative activity, inhibition of enzymes that activate carcinogens, modification of signal transduction pathways, and interactions with receptors and/or proteins, described in [
6]. Quercetin was reported to inhibit enzymatic activity of fatty acid synthase (FASN) and arrest cell growth [
7]. It was shown to effectively inhibit growth in NPC HEN1 cells [
8], human head and neck squamous cell carcinoma [
9], human leukemic T-cells [
10], human gastric cancer HGC-27 cells [
11] and modulates Caco-2 human colorectal adenocarcinoma cell proliferation in a biphasic way [
12]. To overcome obstacles associated with the limitation of cancer chemotherapy, possible biochemical modulation of anticancer drugs in concomitant with other agents, have been evaluated [
13]. Here, we report the effects of quercetin treatment alone and in combination with cisplatin, in a set of EBV-negative and EBV-positive NPC cell line.