Design, Synthesis, and Bioactivity of Cyclic Lipopeptide Antibiotics with Varied Polarity, Hydrophobicity, and Positive Charge Distribution.

Twenty-three polymyxin analogs with variations at nine amino acid positions were synthesized and assessed for antimicrobial activity and renal cytotoxicity. Compounds , , , and (MIC = 0.125-4 μg/mL) had similar or stronger activities against susceptible and drug-resistant strains of , , , and compared to polymyxin B (MIC = 1-2 μg/mL).

Nrf2 mediates the resistance of human A549 and HepG2 cancer cells to boningmycin, a new antitumor antibiotic, in vitro through regulation of glutathione levels.

NF-E2-related factor 2 (Nrf2) is a transcription factor and a pivotal factor in the induction of the cell defense system. Recent reports show that Nrf2 plays critical roles in tumor heterogeneity and drug resistance. In the present study we investigated whether and how Nrf2 mediated the resistance of human cancer cells to boningmycin (BON), a new antitumor antibiotic of the bleomycin family.

Synthesis and Bioactivity Investigation of the Individual Components of Cyclic Lipopeptide Antibiotics.

In this paper, 26 natural polymyxin components and a new derivative S were synthesized, and their differences in efficacy and toxicity have been investigated. Almost all of the synthesized components showed strong activity against both susceptible and resistant strains of E. coli, K.

[Tumor heterogeneity and drug resistance of targeted antitumor agents].

The popular application of targeted antitumor agents has greatly improved the efficacies of tumor therapy. However, some patients develop drug resistance after the administration with them for six to twelve months, leading to the failure of treatment. The cause of it is mainly due to tumor heterogeneity.

[Mechanisms of yanshu injection for overcoming multidrug resistance in breast carcinoma MCF-7 cells: an experimental research].

Objective: To investigate the mechanism of Yanshu Injection (YI) for overcoming multidrug resistance in breast carcinoma MCF-7 cells.

Methods: Human breast carcinoma MCF-7 cells and doxorubicin-resistant MCF-7/DOX cells were treated with YI. Its inhibition on the cell proliferation was detected by MTT assay.

Puerarin inhibits angiotensin II-induced cardiac hypertrophy via the redox-sensitive ERK1/2, p38 and NF-κB pathways.

Aim: To investigate the effects of puerarin (Pue), an isoflavone derived from Kudzu roots, on angiotensin II (Ang II)-induced hypertrophy of cardiomyocytes in vivo and in vitro.

Methods: C57BL/6J mice were infused with Ang II and treated with Pue (100 mg·kg(-1)·d(-1), po) for 15 d. After the treatment, systolic blood pressure (SBP) and left ventricular wall thickness were assessed.

[Study of a novel compound 2460A with activities produced by fungus].

With IL-6R as target, a new compound 2460A was identified from fungus using HTS screening model. The taxonomics of the produced strain was confirmed to be Trichoderma hazianum rifai after sequencing analysis of rDNA-ITS (internal transcribed spacer). Results showed that this compound has a binding activity on IL-6R competed with IL-6, thus it is a new ligand of IL-6R originating from microbe.

[Mechanism of Chinese herbal compound Zilongjin for antagonizing multi-drug resistance of tumor cells].

Objective: To explore the mechanism of action of Zilongjin (ZLJ) in antagonizing multi-drug resistance (MDR) of tumor cells.

Methods: MDR tumor cells, including human breast cancer cell line MCF-7 and MCF-7/DOX, and human oral epithelial cancer cells KB and KBV200, were treated with ZLJ. The inhibition of ZLJ on cell proliferation was determined with MTT assay; cell cycle and fluorescence dye Rhodamine 123 intensity were detected by flow cytometry; and the expression of related proteins was examined by Western blot.

Role of prosurvival molecules in the action of lidamycin toward human tumor cells.

Objective: Lidamycin, an enediyne antibiotic, leads to apoptosis and mitotic cell death of human tumor cells at high and low concentrations. The reason why tumor cells have distinct responses to lidamycin remains elusive. This study was to elucidate if cellular prosurvival molecules are involved in these responses.

[Mechanism of apoptosis induced by SIRT1 deacetylase inhibitors in human breast cancer MCF-7 drug-resistant cells].

The mechanism of apoptosis induced by SIRT1 deacetylase inhibitors in both human breast cancer MCF-7 and MCF-7 doxorubicin-resistant cells was studied. MTT assay was used to detect growth-inhibitory effect on the cells. Protein expression was detected by Western blotting.

Reversal of apoptotic resistance by Lycium barbarum glycopeptide 3 in aged T cells.

Objective: To study whether Lycium barbarum glycopeptide 3 (LBGP3) affects T cell apoptosis in aged mice.

Methods: LBGP3 was purified with DEAE cellulose and Sephadex columns. Apoptotic "sub-G1 peak" was detected by flow cytometry and DNA ladder was resolved by agarose gel electrophoresis.

[Effects of lidamycin on apoptotic gene expressions and cytoskeleton in human hepatoma bel-7402 cells].

Background & Objective: Lidamycin, one of enediyne antitumor antibiotics, was isolated by our institute. It is the focus of intense due to its unique chemical structure and potent cytotoxicities to tumor cells in vivo and in vitro. In addition to cleavage of DNA, effect of lidamycin on apoptotic gene expressions and cytoskeleton may involve in its high activities.

Effects of lidamycin on genomic DNA in human hepatoma BEL-7402 cells.

Aim: To further study the effect of enediyne antibiotic lidamycin (C1027) on genomic DNA in human hepatoma BEL-7402 cells.

Methods: The DNA patterns were detected by agarose gel electrophoresis. The gene damage was revealed by Southern hybridization.

Characteristics of mitotic cell death induced by enediyne antibiotic lidamycin in human epithelial tumor cells.

Mitotic cell death, a different cell death mode from apoptosis, has been focused on in tumor therapy. It may involve the mechanism of highly potent cytotoxicities of enediyne antibiotics toward tumor cells. We describe the characteristics of mitotic cell death induced by enediyne antibiotic lidamycin at low concentrations (0.