This study is to investigate the antitumor activity of CIP-36 on multidrug resistant human oral squamous carcinoma cell line (KBV200 cells) in vitro and the possible anticancer mechanisms. MTT assay, Hoechst fluorescein stain, RT-PCR and immunohistochemistry were carried out on KBV200 and KB cells. The growth of many tumor cells was obviously inhibited by CIP-36, especially the multidrug resistant cells KBV200. Obvious apoptosis could be observed in the Hoechst 33342 staining experiments. The results of RT-PCR showed that the levels of p53, p21, caspase-3 and bax mRNA increased, and meanwhile the expression of mdr-1 and bcl-2 mRNA decreased in a dose-dependent manner. The data were significantly different from that of vehicle. The expression of P-gp significantly decreased with the increasing dosage of CIP-36 examined by immunohistochemistry. It can be concluded that CIP-36 could change resistance-related genes and proteins to overcome multidrug resistance in the KBV200 cell line.

Objective:This work developed a novel and convenient detection method which realized rapid and sensitive detection of the viral nucleic acid.Methods:Here we established a novel nucleic acid detection method based on a graphene field effect transistor (g-FET). By anchoring a chemical molecule on the sensing interface and then modifying with the highly sensitive DNA tetrahedral probes, it realized accomplish highly sensitive detection of the viral nucleic acid. By measuring the transfer curve of the devices, it can make the biological signal of the hybridization for the probe molecule and the target RNA converted into an electrical signal of the g-FET devices. Then through the signal amplification of the field effect transistor (FET) device, it realized a high-sensitive detection of the viral RNA.Results:The DNA tetrahedron probe we designed was targeted at the ORF1 ab gene region of the 2019 novel coronavirus (2019-nCoV) RNA. The target RNA was hybridized and bound by the principle of base-pair complementation. Then we tested the 2019-nCoV simulative RNA samples with different concentrations in saliva, when the concentration of target RNA increased, the Dirac point of the devices presented a regular leftward offset. The limited of detection concentration of this sensor can reach 0.05 copy/μl, and the response time was shorter than 5 minutes in 100 μl volume of tested liquid. Conclusions:In this work, we developed a novel g-FET sensor based on DNA tetrahedral probes, which realized a rapid and sensitive detection of viral nucleic acid.