In summary we demonstrated the high potency

In summary, we demonstrated the high potency of fluxametamide against M. domestica, L. striatellus, and T. urticae GABACls, which leads to high acaricidal/insecticidal effects on these arthropod pests. In contrast to its high potencies against the GABACls of arthropod pests, fluxametamide exhibited little or no antagonistic activity against rat GABACls and human GlyCls, whereas fipronil and its metabolite have antagonistic activity against mammalian GABACls [43,44]. Overall, fluxametamide is a novel potent insecticide with higher safety for humans and other mammals.
Acknowledgments We would like to thank Dr. Y. Kubo (National Institute for Physiological Sciences) for a gift of the pGEMHE plasmid. We also thank Dr. M. Matsumura (NARO Kyushu Okinawa Agricultural Research Center) for providing fipronil-resistant small brown planthoppers.
Introduction Recently, the expression and activity of different ion channels mark and regulate specific stages of cancer progression. Numerous subsequent studies have established the contribution of ion channels in virtually all basic cellular processes, including crucial roles in maintaining tissue homeostasis such as cell cycle, proliferation, differentiation, migration and apoptosis [1], [2]. Indicative data including our own showed that volume-activated chloride channels (VACC) are functional modulated during cetp inhibitor progression and related to cell proliferation. Inhibition of VACC (either expression or channel function) by pharmaceutical, oligo-antisense, blocking antibody or siRNA led to the reduction in cell proliferation in several human tumor cell lines [3], [4], [5], [6]. In our recent investigation, using the human poorly-differentiated nasopharyngeal carcinoma cells (CNE-2Z) and the human normal/immortal nasopharyngeal epithelial cells (NP69-SV40T), the growth of cancerous cells is more dependent on the activities of volume-activated chloride channels than that of the normal cells by using the classical chloride channels blockers and specific small interfere RNA (siRNA) to silence the expression of the chloride channel protein (ClC-3) [7]. These growing experimental and preclinical evidence indicating that the chloride channels should be included among the novel targets for cancer therapy. Apoptosis is a multi-step and multi-pathway cell death program, which is controlled by a diverse range of cell signals [8]. A major hallmark of apoptosis is normotonic cell shrinkage called apoptotic volume decrease (AVD) that occurs at an early phase preceding caspase activation, DNA laddering, and cell fragmentation [9] [10]. Although debates were existed, there is no doubt that ionic fluxes play a pivotal role in AVD and the volume-sensitive Cl− channel has been highly regarded [11], [12], [1]. Emodin (1,3,8-trihydroxy-6-methyl-anthraquinone) is an active anthraquinone found in Chinese herb Rhubarb (Rheum palmatum). Emodin was found to alter the expression of a number of proteins involved in oxidative stress, cell-cycle arrest, anti-metastasis and apoptosis [13]. Emodin was recently found to be able to induce DNA damage through excessive production of ROS in human lung carcinoma cells [14]. This compound has been shown extensively pharmacological function including anti-inflammatory, anti-bacterial, antiviral, hepatoprotection, neuroprotection and anti-cancer [15]. Numerous studies have indicated that emodin showed highly active anticancer in variety of human cancer cell lines including human hepatoma [16], leukemia [17], glioma [18], lung carcinoma cells [19] and human colon cancer cells [20]. However, there is no available information to show emodin induced apoptosis in human nasopharyngeal cancerous cells and its anticancer mechanism need to be further elucidated.
Materials and methods
Results
Discussion Nasopharyngeal carcinoma (NPC) is a malignant tumor with obvious regional and racial characteristics, which is rather prevalent in southern China, especially in high-incidence regions such as Guangdong and Hong Kong [27]. At present, treatment of NPC is mainly intensive radiotherapy and adjuvant chemotherapy in clinical. However, despite producing a certain beneficial effect, 10% of the patients experienced relapses and tumor metastasis after their initial treatment [28], [29]. Thus, with the development and clinical application of molecule-targeted drugs such as gefitinib, trastuzumab and rituximab [30], the molecule-targeted treatment of tumors has been widely accepted for its specific cytotoxicity against carcinoma cells.