Dongmei Yan

The liver-targeting study of the N-galactosylated chitosan in vivo and in vitro

Abstract In order to study the liver targeting of the N-galactosylated chitosan (GC) polymer in liver, we first conjugated the lactobionic acid with chitosan (CS) to obtain the carrier of GC with different degree of substitution of lactosyl group. Western blot was performed to detect the expression levels of the asialoglycoprotein receptors (ASGPR) in the cell lines of HepG2, SMMC-7721, and HL-7702. The protein level of ASGPR was lower in HepG2 compared to HL-7702 and SMMC-7721. Although all treated by CS, viabilities of HL-7702 and HepG2 did not experience any significant drop, while viability of SMMC-7721 decreased 15% on average from control. It was the first data about the inhibitory effect of GC on the liver cells. Fluorescein isothiocyanate (FITC) labeled GC (GC-FITC) was injected intravenously into mice at a dose of 0.02 μmol/mouse. GC-FITC showed maximum liver localization at 5 min and even detectable at 48 h after injection. Further, the accumulation of GC in liver was about 5.4-fold higher than that of CS. In conclusion, GC demonstrated its higher efficacy in drug liver targeting and thus could be a more promising drug or gene carrier in future therapies.

Knockdown of Merm1/Wbscr22 attenuates sensitivity of H460 non-small cell lung cancer cells to SN-38 and 5-FU without alteration to p53 expression levels.

Merm1/Wbscr22 is a novel metastasis promoter that has been shown to be involved in tumor metastasis, viability and apoptosis. To the best of our knowledge, there are currently no studies suggesting the possible correlation between the expression of Merm1/Wbscr22 in tumor cells and chemosensitivity to antitumor agents. In the present study, two human non-small cell lung cancer cell lines, H1299 and H460, were used to investigate whether Merm1/Wbscr22 affects chemosensitivity to antitumor agents, including cisplatin (CDDP), doxorubicin (ADM), paclitaxel (PTX), mitomycin (MMC), 7-Ethyl-10-hydroxycamptothecin (SN-38; the active metabolite of camptothecin) and 5-fluorouracil (5-FU). Merm1/Wbscr22 knockdown cell lines (H1299-shRNA and H460-shRNA) and negative control cell lines (H1299-NC and H460-NC) were established by stable transfection, and the efficiency of Merm1/Wbscr22 knockdown was confirmed by western blotting, immunofluorescence microscopy and quantitative polymerase chain reaction. The results demonstrated that shRNA-mediated knockdown of Merm1/Wbscr22 did not affect cell proliferation in vitro and in vivo. The H460 cells harboring wild type p53 were markedly more sensitive to all six antitumor agents as compared with the p53-null H1299 cells. Downregulation of Merm1/Wbscr22 did not affect H1299 sensitivity to any of the six antitumor agents, whereas attenuated H460 sensitivity to SN-38 and 5-FU, without significant alteration in p53 at both mRNA and protein levels, was identified. The reduced H460 sensitivity to SN-38 was further confirmed in vivo. SN-38 demonstrated significant tumor growth inhibitory activity in both H460 and H460‑NC tumor xenograft models, but only marginally suppressed the H460-shRNA xenograft tumor growth. Furthermore, CDDP (4, 10, 15 µg/ml)-resistant human non-small lung cancer cells A549 (A549-CDDPr-4, 10, 15) expressed significant amounts of Merm1/Wbscr22 protein, as compared with the parental A549 cells. In conclusion, shRNA-mediated knockdown of Merm1/Wbscr22 attenuates H460 sensitivity to SN-38 and 5-FU, suggesting Merm1/Wbscr22 is involved in chemosensitivity to SN-38 and 5-FU in H460 cells. No direct correlation between the p53 expression level and altered chemosensitivity was identified.

Synthesis and biological evaluation of novel cyclopropyl derivatives as subtype-selective ligands for estrogen receptor

Tamoxifen is the most commonly used selective estrogen receptor modulators (SERMs); however, patients often develop the acquired drug resistance on tamoxifen therapy. The aim of this study was to develop new SERMs.

WBSCR22 confers oxaliplatin resistance in human colorectal cancer

Human WBSCR22 gene is involved in tumor metastasis, cell growth and invasion, however, its role in chemosensitivity to antitumor agents remains unknown. In this study, we analyzed the TCGA cohort and found the expression of WBSCR22 was significantly elevated in human colorectal cancer (CRC) tissue. WBSCR22 could be served as an independent risk predictor for overall survival (OS), and up-regulated WBSCR22 could predict unfavorable OS for CRC patients. Knockdown of WBSCR22 significantly sensitized CRC cells to oxaliplatin in vitro and in vivo, while overexpression of WBSCR22 led to cellular resistance to oxaliplatin treatment. Although WBSCR22 knockdown did not change cell cycle, it increased the oxaliplatin-induced cellular apoptosis. WBSCR22 knockdown augmented the oxaliplatin-induced intracellular reactive oxygen species (ROS) production and ROS-induced 8-oxoguanine (8-oxoG) oxidative lesion accumulation, likely sensitizing oxaliplatin treatment. These results demonstrate that WBSCR22 is involved in CRC resistance to oxaliplatin, suggesting WBSCR22 may represent a novel oxaliplatin resistance biomarker as well as a potentail target for CRC therapeutics.

Synthesis, Characterization and In Vitro Cytotoxicity of Diorganotin Complexes of 3,5-Dinitrosalicylic Acid

The diorganotin derivatives of 3,5-dinitrosalicylic acid, R2SnL (L = 3,5-(NO2)2–2-OC6H2COO, R = C2H5 1; n-C4H9 2; c-C6H11 3) have been synthesized and characterized by elemental analysis, IR, and NMR spectra. The crystal structure of (n-C4H9)2SnL(CH3OH) has been determined. This compound is a novel one-dimensional ladder-shaped supramolecular polymer formed by bridged coordination of carboxyl group to tin and intermolecular hydrogen bond, and tin atom possesses a distorted octahedral geometry. The in vitro cytotoxicities of 2 and 3 against two human tumor cells, A549 and CoLo205, are higher than those of cis-platin, and the activity decreased in the order 3 >2 >1.

Synthesis, Characterization, and in vitro Cytotoxicity of Organotin Derivatives of 4-Biphenylcarboxylic Acid

The di- and tri-organotin derivatives of 4-biphenylcarboxylic acid, {[(CH3CH2CH2CH2)2Sn(OCOC6H4C6H5)]2O}2 (1) and R3SnOCOC6H4C6H5 (R = C6H5, 2; c-C6H11, 3; C6H5C(CH3)2CH2, 4), have been synthesized and characterized by elemental analysis, IR, 1H, and 13C NMR spectroscopies. The crystal structures of 1 and 2 have been determined. Compound 1 is a centrosymmetric dimmer with two distinct types of carboxylate moieties and tin atoms with distorted trigonal bipyramidal geometries and 2 possesses a distorted tetrahedral structure. The in vitro cytotoxicity of 4 against three human tumor cell lines was found to be higher than that for cis-platin used clinically.

Notch1 suppresses prostate cancer cell invasion via the metastasis‑associated 1‑KiSS‑1 metastasis‑suppressor pathway

Notch1 is a type-1 transmembrane receptor which has been demonstrated to be involved in proliferation in various organisms. A number of studies have proposed that Notch signaling may be aberrantly activated, thus contributing to development, invasion and metastasis in a variety of human cancers. In the present study, the function and mechanism of Notch1 in human prostate cancer (PCa) LNCaP cells in vitro was investigated. Notch1 and cleaved-Notch1 expression were evaluated in human PCa cell lines, including LNCaP, PC-3 and DU 145, and the human prostate epithelial RWPE-1 cell line. LNCaP cells were transfected with Notch1-targeting short hairpin RNAs (shRNAs) and the level of proliferation, the ability to invade and the expression of genes associated with cancer cell invasion were subsequently investigated. Notch1 was highly expressed in LNCaP, PC-3 and DU 145 cells compared with RWPE-1 cells, while cleaved-Notch1 was expressed in LNCaP, PC-3 and DU 145 cells, and only to a minimal extent in RWPE-1 cells. Knockdown of Notch1 by shRNA in LNCaP cells markedly decreased cell invasion through Matrigel and inhibited cell proliferation 48 h following transfection. Reverse transcription-quantitative polymerase chain reaction analysis indicated that Notch1-knockdown resulted in a significant reduction of metastasis-associated 1 (MTA1) and increase of KiSS-1 metastasis-suppressor (KISS-1), mitogen-activated protein kinase 4 (MKK4) and cluster of differentiation 82 (KAI1). The present data demonstrated that expression of Notch1 was significantly associated with the invasion of prostate cancer. Knockdown of Notch1 decreased the invasive ability of LNCaP cells, which may be caused by downregulating MTA1 and upregulating KISS-1, MKK4 and KAI1. These findings indicated that targeting Notch1 may provide a novel method of suppressing or treating metastasis in prostate cancer.