KRAS pathway expression changes in pancreatic cancer models by conventional and experimental taxanes

Third-generation taxanes SB-T-121605 and SB-T-121606 are effective in pancreatic ductal adenocarcinoma

Pancreatic cancer is a severe malignancy with increasing incidence and high mortality due to late diagnosis and low sensitivity to treatments. Search for the most appropriate drugs and therapeutic regimens is the most promising way to improve the treatment outcomes of the patients. This study aimed to compare (1) in vitro efficacy and (2) in vivo antitumor effects of conventional paclitaxel and the newly synthesized second (SB-T-1216) and third (SB-T-121605 and SB-T-121606) generation taxanes in KRAS wild type BxPC-3 and more aggressive KRAS G12V mutated Paca-44 pancreatic cancer cell line models. In vitro, paclitaxel efficacy was 27.6 ± 1.7 nM, while SB-Ts showed 1.7-7.4 times higher efficacy. Incorporation of SB-T-121605 and SB-T-121606 into in vivo therapeutic regimens containing paclitaxel was effective in suppressing tumor growth in Paca-44 tumor-bearing mice at small doses (≤3 mg/kg). SB-T-121605 and SB-T-121606 in combination with paclitaxel are promising candidates for the next phase of preclinical testing.

Anticancer regimens containing third generation taxanes SB-T-121605 and SB-T-121606 are highly effective in resistant ovarian carcinoma model

Taxanes are widely used in the treatment of ovarian carcinomas. One of the main problems with conventional taxanes is the risk of development of multidrug resistance. New-generation synthetic experimental taxoids (Stony Brook Taxanes; SB-T) have shown promising effects against various resistant tumor models. The aim of our study was to compare the in vitro efficacy, intracellular content, and in vivo antitumor effect of clinically used paclitaxel (PTX) and SB-Ts from the previously tested second (SB-T-1214, SB-T-1216) and the newly synthesized third (SB-T-121402, SB-T-121605, and SB-T-121606) generation in PTX resistant ovarian carcinoma cells NCI/ADR-RES. The efficacy of the new SB-Ts was up to 50-times higher compared to PTX in NCI/ADR-RES cells in vitro. SB-T-121605 and SB-T-121606 induced cell cycle arrest in the G2/M phase much more effectively and their intracellular content was 10-15-times higher, when compared to PTX. Incorporation of SB-T-121605 and SB-T-121606 into therapeutic regimens containing PTX were effective in suppressing tumor growth in vivo in NCI/ADR-RES based mice xenografts at small doses (≤3 mg/kg), where their adverse effects were eliminated. In conclusion, new SB-T-121605 and SB-T-121606 analogs are promising candidates for the next phase of preclinical testing of their combination therapy with conventional taxanes in resistant ovarian carcinomas.

The Role of TRIP6, ABCC3 and CPS1 Expression in Resistance of Ovarian Cancer to Taxanes

The main problem precluding successful therapy with conventional taxanes is de novo or acquired resistance to taxanes. Therefore, novel experimental taxane derivatives (Stony Brook taxanes; SB-Ts) are synthesized and tested as potential drugs against resistant solid tumors. Recently, we reported alterations in ABCC3, CPS1, and TRIP6 gene expression in a breast cancer cell line resistant to paclitaxel. The present study aimed to investigate gene expression changes of these three candidate molecules in the highly resistant ovarian carcinoma cells in vitro and corresponding in vivo models treated with paclitaxel and new experimental Stony Brook taxanes of the third generation (SB-T-121605 and SB-T-121606). We also addressed their prognostic meaning in ovarian carcinoma patients treated with taxanes. We estimated and observed changes in mRNA and protein profiles of ABCC3, CPS1, and TRIP6 in resistant and sensitive ovarian cancer cells and after the treatment of resistant ovarian cancer models with paclitaxel and Stony Brook taxanes in vitro and in vivo. Combining Stony Brook taxanes with paclitaxel caused downregulation of CPS1 in the paclitaxel-resistant mouse xenograft tumor model in vivo. Moreover, CPS1 overexpression seems to play a role of a prognostic biomarker of epithelial ovarian carcinoma patients’ poor survival. ABCC3 was overexpressed in EOC tumors, but after the treatment with taxanes, its up-regulation disappeared. Based on our results, we can suggest ABCC3 and CPS1 for further investigations as potential therapeutic targets in human cancers.