CARP-1 functional mimetics are novel inhibitors of drug-resistant triple negative breast cancers

Abstract

Doxorubicin and Cisplatin are the frontline therapeutics for treatment of the triple negative breast cancers (TNBCs). Emergence of drug-resistance often contributes to failure of drugs and poor prognosis, and thus necessitates development of new and improved modalities to treat TNBCs. We generated and characterized chemotherapy-resistant TNBC cells following their culture in chronic presence of Doxorubicin or Cisplatin, and tested whether their viabilities were inhibited by a novel class of CARP- 1 functional mimetic (CFM) compounds. Analogs of parent compound CFM-4 were obtained through structure-activity based medicinal chemistry studies. CFM-4.16, a novel analog of CFM-4, caused superior inhibition of viability of TNBC cells when used in combination with doxorubicin. Doxorubicin and cisplatin inhibited viabilities of parental cells with GI50 dose of 0.02–0.1 μM and 1.65 μM, respectively. The GI50 dose of doxorubicin for doxorubicin-resistant TNBC cells was ≥ 10.0 μM. For Cisplatin-resistant cells, the GI50 dose of Cisplatin was ≥ 6–15.0 μM for MDA-MB-468 sublines and ≥ 150.0 μM for MDA-MB-231 sublines. CFM-4.16 inhibited viability of chemotherapy-resistant TNBC cells, in part by inhibiting oncogenic cMet activation and expression, stimulating CARP-1 expression, caspase-8 cleavage and apoptosis. CFM-4.16 pretreatment enhanced anti-TNBC efficacies of inhibitors of cMET (Tevatinib) or cSrc (Dasatinib). CFM-4.16 suppressed growth of resistant TNBC cells in soft agar as well as in three-dimensional suspension cultures derived from enriched, stem-like cells. Finally, a nanolipid formulation of CFM-4.16 in combination with doxorubicin had superior efficacy in inhibiting TNBC xenograft growth. Our findings collectively demonstrate therapeutic potential of CFM-4.16 for parental and drug-resistant TNBCs.

A CARP-1 functional mimetic loaded vitamin E-TPGS micellar nano-formulation for inhibition of renal cell carcinoma

“…A 4.0μM dose of CFM-4.16 on the other hand provoked ∼80% reduction in the viabilities of all the Everolimus-resistant RCC cells. These data corroborate our current findings in Figure 1 and our recent studies demonstrating increased effectiveness of CFM-4.16 in attenuating viabilities of the parental RCC cells as well as drug-resistant RCC (Figure 2 ) and TNBC cells [ 26 ].…”

“…Our prior findings had indicated anti-cancer properties of a novel class of CFM compounds [ 10 ], and our recent medicinal chemistry-based structure-activity relationship (SAR) studies reported identification of CFM analogs, in particular CFM-4.16, that was a superior inhibitor of parental and drug-resistant human and murine triple-negative breast cancer cells in vitro and in vivo [ 26 ]. Since emergence of resistance to current therapeutics remains a formidable problem in effective treatment and management of RCCs in clinic [ 5 – 7 ], we speculated whether CFM class of compounds would be effective inhibitors of RCC cells and to the extent, these compounds would be suitable to inhibit the resistant RCCs.…”

Tumor hypoxia directed multimodal nanotherapy for overcoming drug resistance in renal cell carcinoma and reprogramming macrophages

“…Structure and synthesis of the C4.16 compound have been previously described [16,40]. A stock solution of 50 mM of C4.16 was solubilized in dimethyl sulfoxide (DMSO) and stored at –20°C for further use.…”

“…Cells were cultured with ~70–80% confluence. We cultured Evr-res A498 cells to form 3D spheroid structure based on previously published methods [16,40]. Briefly, the cells were washed twice in 1 × PBS, trypsinized and pelleted the cells with 200 ×g centrifugation at room temperature.…”

“…The generation of RCC cell-derived subcutaneous tumor was done according to our previously published protocols approved by the Institutional Laboratory Animal Care & Use Committee (IACUC) at the Wayne State University [16,40]. Female, 5–6 weeks old nu/nu mice were obtained from Jackson Laboratory, Bar Harbor, ME.…”