Reactive Oxygen Species and Autophagy Associated Apoptosis and Limitation of Clonogenic Survival Induced by Zoledronic Acid in Salivary Adenoid Cystic Carcinoma Cell Line SACC-83

Abstract

Salivary adenoid cystic carcinoma is an epithelial tumor in the head and neck region. Despite its slow growth, patients with salivary adenoid cystic carcinoma exhibit poor long term survival because of a high rate of distant metastasis. Lung and bone are common distant metastasis sites. Zoledronic acid, a third generation bisphosphonate, has been used for tumor-induced osteolysis due to bone metastasis and has direct antitumor activity in several human neoplasms. Here, we observed that zoledronic acid inhibited salivary adenoid cystic carcinoma cell line SACC-83 xenograft tumor growth in nude mice. In vitro, zoledronic acid induced apoptosis and reduced clonogenic survival in SACC-83. Flow cytometry and western blotting indicated that the cell cycle was arrested at G0/G1. Zoledronic acid treatment upregulated reactive oxygen species as well as the autophagy marker protein LC-3B. Reactive oxygen species scavenger N-acetylcysteine and autophagy antagonist 3-methyladenine decreased zoledronic acid-induced apoptosis and increased clonogenic survival. Silencing of the autophagy related gene Beclin-1 also decreased zoledronic acid-induced apoptosis and inhibition of clonogenic formation. In addition, isobolographic analysis revealed synergistic effects on apoptosis when zoledronic acid and paclitaxel/cisplatin were combined. Taken together, our results suggest that zoledronic acid induced apoptosis and reduced clonogenic survival via upregulation of reactive oxygen species and autophagy in the SACC-83 cell line. Thus, zoledronic acid should be considered a promising drug for the treatment of salivary adenoid cystic carcinoma.

Zoledronic acid augments the radiosensitivity of cancer cells through perturbing S- and M-phase cyclins and p21CIP1 expression

“…Of note, the expression levels of cyclins D1 and E, as well as p27 KIP1 , were not significantly altered upon combined treatment. These results are in accordance, at least in part, with other cancers reported previously (13,(24)(25)(26).…”

“…It has been reported that ZOL may induce cell-cycle prolongation by altering the expression of certain cyclins and their associated regulatory proteins (13,(24)(25)(26). The present study also revealed that co-treatment with ZOL plus IR elevated the expression levels of S-and M-phase cyclins, cyclin A and B, while downregulated the cyclin-dependent kinase inhibitor p21 CIP1 , which may lead to cell cycle arrest between intra-S and M phases.…”

“…An MTT colorimetric assay was used to measure the proliferation rate of tumor cells treated with ZOL as described previously (13,19). Briefly, cells were plated in triplicate at a density of 4x10 3 cells per well on 96-well plates (Corning Costar, Cambridge, MA, USA), After 24 h of culture at 37˚C, cells were incubated with ZOL at various concentrations (2-32 µM) at 37˚C for 48 or 72 h, followed by MTT assays.…”

“…ZOL is considered to possess antitumor activity, particularly in combination with chemotherapeutic anticancer drugs (10)(11)(12). This effect of ZOL could be observed on cancer cells derived from a variety of tumors, including breast, prostate and pancreatic cancers, by inducing cell apoptosis and inhibiting cell invasion, adhesion and angiogenesis (10)(11)(12)(13). Currently, numerous patients with bone metastases secondary to a broad range of solid tumors are benefiting from the antitumor effects of ZOL (14).…”

Zoledronic acid suppresses metastasis of esophageal squamous cell carcinoma cells through upregulating the tight junction protein occludin

“…Recent evidences also suggest that ZOL has direct or indirect anti-tumor effects (Zhao et al 2012;Matsumoto et al 2005;Ge et al 2014). The mechanism consists of inducing cell apoptosis, impairing cell migration and invasion, modulating immune response mediated by cdT cells and anti-angiogenesis effect (Zhao et al 2012;Matsumoto et al 2005;Ge et al 2014;Hiroshima et al 2014;Yuasa et al 2007). To date, the clinical benefits of ZOL have been extended to patients with bone metastases secondary to a broad range of solid tumors (Hiroshima et al 2014;Yuasa et al 2007).…”