idn-5109 and Breast-Neoplasms

Bayer Corp, under license from Indena SpA, is developing BAY-59-8862, a taxane synthesized from 14beta-hydroxy-10-deacetylbaccatin III, for the potential treatment of cancer.

Topics: Animals; Antineoplastic Agents; Breast Neoplasms; Bridged-Ring Compounds; Clinical Trials, Phase I as Topic; Clinical Trials, Phase II as Topic; Drug Evaluation, Preclinical; Female; Humans; Ovarian Neoplasms; Structure-Activity Relationship; Taxoids

Paclitaxel (PTX) is widely used to treat breast and ovarian cancers, but innate and acquired resistance often compromises its applications. The objective of this study was to screen new-generation taxanes for their efficiency against both PTX-sensitive and PTX-resistant breast cancer cells. From twelve compounds, difluorovinyl-ortataxel (DFV-OTX) displayed potent cytotoxic activities against both PTX-sensitive and PTX-resistant breast cancer cells. Moreover, DFV-OTX effectively induced tubulin/microtubule polymerization and G2/M phase arrest, leading to apoptosis in both PTX-sensitive and PTX-resistant cancer cells. Molecular docking analysis showed that DFV-OTX possesses unique hydrogen-bonding and van der Waals interactions with β-tubulin. LC-MS/MS analysis also demonstrated that the intracellular drug amount of DFV-OTX was lower than that of PTX, which would be critical to overcome PTX-resistance. Furthermore, DFV-OTX exhibited clear efficacy in the MCF-7R and MDA-MB-231R tumor xenografts in mouse models. Taken together, our results demonstrate that the novel taxane, DFV-OTX, can effectively overcome PTX-resistance in MDA-MB-231R cells, wherein the drug resistance was attributed to ABCB1/ABCG2 upregulation and a distinct mode of action in MCF-7R cells. Our results strongly indicate that DFV-OTX is a promising chemotherapeutic agent for the treatment of PTX-resistant cancers.

Topics: Animals; Antineoplastic Agents; Apoptosis; ATP Binding Cassette Transporter, Subfamily B, Member 1; Breast Neoplasms; Bridged-Ring Compounds; Cell Line, Tumor; Drug Resistance, Neoplasm; Endoplasmic Reticulum Stress; Female; G2 Phase Cell Cycle Checkpoints; Humans; Mice; Mice, Inbred BALB C; Paclitaxel; Taxoids; Tubulin

The taxane paclitaxel (Taxol) is often of limited efficacy in chemotherapeutic regimens because some cancer cells express high levels of the efflux pump, P-glycoprotein (Pgp), which removes the drug from the cells. The orally active paclitaxel analog IDN-5109 has been reported to overcome Pgp-mediated drug resistance. We tested whether IDN-5109 acts by modulating Pgp activity.. Human MDA435/LCC6mdr1 and MDA435/LCC6 breast carcinoma cells, which express and do not express Pgp, respectively, were incubated with [3H]IDN-5109 and paclitaxel to determine intracellular drug accumulation. Flow cytometry was used to analyze intracellular retention of two Pgp substrates, rhodamine 123 (Rh-123) and doxorubicin, in both breast carcinoma cell lines and in human colon carcinoma cells (SW-620, DLD1, and HCT-15, whose Pgp levels vary) treated with different taxanes. The effects of IDN-5109 and paclitaxel on tumor growth in vivo were studied with the use of tumors established through xenografts of Pgp-expressing SW-620 and DLD1 cells in severe combined immunodeficiency mice. All statistical tests were two-sided.. Pgp-expressing cells treated with IDN-5109 or with the taxane-based drug resistance reversal agent tRA96023, which blocks Pgp activity, retained 8.1- and 9.4-fold more Rh-123 (P =.0001), respectively, and 1.7- and 1.9-fold more doxorubicin (P =.001), respectively, than cells treated with paclitaxel. Non-Pgp-expressing cells treated similarly demonstrated no increased retention of either substrate. MDA435/LCC6mdr1 cells retained 5.3-fold more [3H]IDN-5109 than [3H]paclitaxel after 2 hours (P =.01). IDN-5109 showed statistically significantly higher tumor growth inhibition than paclitaxel against the SW-620 xenograft (P =.003).. IDN-5109 modulates Pgp activity, resulting in superior tumor growth inhibition against Pgp-expressing tumors as compared with paclitaxel. IDN-5109 may broaden the spectrum of taxane use to include colon tumors.

Topics: Administration, Oral; Animals; Antibiotics, Antineoplastic; Antineoplastic Agents, Phytogenic; ATP Binding Cassette Transporter, Subfamily B, Member 1; Breast Neoplasms; Bridged-Ring Compounds; Colonic Neoplasms; Doxorubicin; Drug Screening Assays, Antitumor; Female; Flow Cytometry; Fluorescence; Humans; Male; Paclitaxel; Taxoids; Tissue Distribution; Transplantation, Heterologous; Tumor Cells, Cultured