Cytotoxicity of compounds in RMS cells and normal human fibroblast cells.

<p>(A) Chemical structures of anti-RMS hits. (B) IC₅₀ values of the compounds in RD and NHFB cells. *, The selectivity index was calculated by dividing the IC₅₀ in NHFB cells by the IC₅₀ in RD cells. (C) The IC₅₀ values of MHPT in SJ-RH30 RMS cells and the normal human fibroblast cell lines MRC-5 and WI-38. #, the selectivity index was calculated by dividing the IC₅₀ in MRC-5 cells by the IC₅₀ in SJ-RH30 cells.</p

Time-dependent morphological changes (A, C) and changes in viability (B, D) of RMS cells treated with DMSO (control) or MHPT (5 μM).

<p>DMSO- treated RMS cells grew exponentially; however the growth of MHPT-treated RMS cells was inhibited significantly. The number of viable RMS cells decreased significantly after treatment with MHPT for 48 h. *, <i>P</i> < 0.05 versus control; #, <i>P</i> < 0.05 versus MHPT at 24 h.</p

MHPT induced RMS cell apoptosis in a dose-dependent manner.

<p>(A) RMS cells were treated with DMSO (control) or MHPT at the indicated concentrations for 48 h. The RMS cells were stained by Guava Nexin regent containing 7-AAD/Annexin-V-PE and analyzed by flow cytometry. In the four windows of each plot, the lower left indicates normal cells, the lower right indicates early apoptotic cells, and the upper right indicates late-phase apoptotic cells or necrotic cells. (B) Western blot analysis of cleaved PARP after MHPT treatment in RMS cells. (C) Caspase 3/7 activity was determined based fluorescence intensity in RD cells. RD cells were treated with DMSO (control) or MHPT (1 μM or 5 μM) for the indicated times. MHPT significantly activated caspase 3/7 in a dose- and time-dependent manner. *, <i>P</i> < 0.05 versus control.</p

MHPT caused G2/M cell cycle arrest of RMS cells in a dose-dependent manner.

<p>RMS cells were treated with DMSO (control) or MHPT at the indicated concentrations for 48 h. (A) RMS cells were stained and analyzed by a flow cytometry. The pink areas indicate arrest at the G1/G0 phase; the green areas indicate arrest at the S phase, the blue areas indicate arrest at the G2/M phase; and the circled areas indicate arrest at the sub-G1 phase. (B) Western blot analysis of p21 expression after MHPT treatment in RMS cells. (C) The ratio of p21 to β-actin was quantified by densitometric analysis using Image J software and normalized to the value of the control group. *, <i>P</i> < 0.05 versus control.</p

The anti-tumor efficacy of MHPT in an RD xenograft tumor model.

<p>(A) RD xenograft tumor growth curve in BALB/C nude mice. The mice were injected with the following: Vehicle (control, 5 doses, every other day), MHPT (40 mg/kg, 5 doses, every other day), or VCR (1 mg/kg, 5 doses, every 4 days). *, <i>P</i> < 0.05 versus the control group, n = 5. (B) Survival percentage of mice after administration. The mice were sacrificed when the tumors grew to nearly 2000 mm³ or other serious toxic signs were observed, including > 20% body weight loss. (C) The body weight of the mice was measured during the experiments. In the control and MHPT groups, the body weights of the mice were stable. In the VCR group, serious body weight loss occurred, and two mice died during experiments. *, <i>P</i> < 0.05 versus the body weights at day 0, n = 5. (D) Blood biochemical and hematological data for the BALB/C nude mice. There was no significant difference between the MHPT group and the control group. In VCR group, WBC, PLT and UREA were decreased significantly. *, <i>P</i> < 0.05 versus the control group, n = 5.</p

The Novel Tubulin Polymerization Inhibitor MHPT Exhibits Selective Anti-Tumor Activity against Rhabdomyosarcoma <i>In Vitro</i> and <i>In Vivo</i>

<div><p>The dose-limiting toxicity caused by standard chemotherapy has become a major roadblock to successful rhabdomyosarcoma chemotherapy. By screening a thiazolidinone library including 372 compounds, a novel synthetic compound, 2-((4-hydroxyphenyl)imino)-5-(3-methoxybenzylidene)thiazolidin-4-one (MHPT), was identified as a potent and selective anti-rhabdomyosarcoma agent. MHPT inhibited 50% of the growth of the rhabdomyosarcoma cell lines RD and SJ-RH30 at 0.44 μM and 1.35 μM, respectively, while displaying no obvious toxicity against normal human fibroblast cells at 100 μM. Further investigation revealed that MHPT suppressed the polymerization of tubulin, leading to rhabdomyosarcoma cell growth arrest at the G2/M phase followed by apoptosis. <i>In vivo</i>, MHPT inhibited tumor growth by 48.6% relative to the vehicle control after 5 intraperitoneal injections of 40 mg/kg without appreciable toxicity to normal tissues and systems in an RD xenograft mouse model, while vincristine caused lethal toxicity when similar growth inhibition was achieved. As a moderate tubulin polymerization inhibitor compared with vincristine, MHPT requires a more dynamic tubulin to exert its cytotoxicity, which is a situation that only exists in cancer cells. This attribute may account for the low toxicity of MHPT in normal cells. Our data suggest that MHPT has the potential to be further developed into a selective anti-rhabdomyosarcoma drug with low toxicity.</p></div

Discovery of Novel Tricyclic Thiazepine Derivatives as Anti-Drug-Resistant Cancer Agents by Combining Diversity-Oriented Synthesis and Converging Screening Approach

An efficient discovery strategy by combining diversity-oriented synthesis and converging cellular screening is described. By a three-round screening process, we identified novel tricyclic pyrido­[2,3-<i>b</i>]­[1,4]­benzothiazepines showing potent inhibitory activity against paclitaxel-resistant cell line H460_TaxR (EC₅₀ < 1.0 μM), which exhibits much less toxicity toward normal cells (EC₅₀ > 100 μM against normal human fibroblasts). The most active hits also exhibited drug-like properties suitable for further preclinical research. This redeployment of antidepressing compounds for anticancer applications provides promising future prospects for treating drug-resistant tumors with fewer side effects

Four new phenolic constituents from the rhizomes of <i>Gastrodia elata</i> Blume

<p>Four new gastrodin derivatives containing a <i>trans</i>-cinnamoyl unit (<b>1–4</b>) and nine known compounds (<b>5–13</b>) were isolated from the rhizomes of <i>Gastrodia elata</i> Blume. All these compounds were evaluated for their neuroprotective effects against 6-hydroxydopamine-induced cell death, and compounds <b>7</b> and <b>12</b> showed potent activities with EC₅₀ values of 10.5 and 10.2 μM, respectively.</p

<i>N</i>‑Deoxycholic acid‑<i>N</i>,<i>O</i>‑hydroxyethyl Chitosan with a Sulfhydryl Modification To Enhance the Oral Absorptive Efficiency of Paclitaxel

Currently, the most prominent barrier to the success of orally delivered paclitaxel (PTX) is the extremely limited bioavailability of delivered therapeutic. In light of this issue, an amphiphilic sulfhydrylated <i>N</i>-deoxycholic acid-<i>N</i>,<i>O</i>-hydroxyethyl chitosan (TGA-DHC) was synthesized to improve the oral bioavailability of PTX. First, TGA-DHC demonstrated substantial loading of PTX into the inner hydrophobic core. A desirable enhancement in the bioavailability of PTX by TGA-DHC was verified by pharmacokinetic studies on rats against Taxol and non-sulfhydrylated DHC micelles. Moreover, cellular uptake studies revealed significant accumulation of TGA-DHC micelles encapsulating PTX or rhodamine-123 into Caco-2 cells via clathrin/caveolae-mediated endocytosis and inhibition of P-gp efflux of substrates. The results of the Caco-2 transport study further confirmed the mechanistic basis of TGA-DHC efficacy; which was attributed to permeabilized tight junctions, clathrin-mediated transcytosis across the endothelium, and inhibition of P-gp. Finally, <i>in vitro</i> mucoadhesion investigations on freshly excised rat intestine intuitively confirmed increased intestinal retention of drug-loaded TGA-DHC through thiol-mediated mucoadhesion. TGA-DHC has demonstrated the capability to overcome what is perhaps the most prominent barrier to oral PTX efficacy, low bioavailability, and serves as a prominent platform for oral delivery of P-gp substrates