SM-164

An adoptive cell targeting delivery of TNFα combined with an IAP antagonist is a novel effective approach to treat breast cancer and could be expanded to treat other solid cancers. Unlike CAR-T cell, this novel adoptive cell is not activated to produce a wide variety of cytokines, except for additional overexpressed TNF, and thus could avoid the severe side effects such as cytokine release syndrome.

Of interest, two Smac mimetics, birinapant and SM164, exhibited this kind of differential enhancement. In tumor xenograft studies, combinations of immunotoxin and birinapant caused complete regressions in MDA-MB-468tumor-bearing mice but not in mice with A431 tumors. We propose that IAPs constitute a barrier to immunotoxin efficacy which can be overcome with combination treatments that include Smac mimetics.

This was consistent with previous reports that BET inhibitors (e.g., OTX015, mivebresib or ABBV-075 and JQ1) are effective against 3q26.2-r AML cell lines, patient-derived (PD) AML cells and PDX models...In follow-up experiments, XIAP/cIAPs inhibitors birinapant (10-1000 nM) or SM-164 (30-1000 nM), chosen based on the MIPE screen outcomes, induced significantly more dose-dependent apoptosis in 3q26.2-r versus the other AML cell lines...Treatment with the dual mTOR/PIK3CA inhibitor NVP-BGT226 (1-30 nM) or navitoclax or Bcl-xL-specific BH3 mimetic A-1155463 also exerted lethality and synergistically induced apoptosis with mivebresib in AML cells with inv3/t(3; 3)...Co-treatment with birinapant and tegavivint also synergistically induced apoptosis in 3q26.2-r AML cells...Additionally, compared to each drug or vehicle control, co-treatment with birinapant and the BETi OTX015 (30 mg/kg/day, by oral gavage) was more effective in reducing AML burden in the xenograft model. These findings demonstrate promising preclinical activity of IAP protein inhibition against the cellular models of AML with inv3/t(3; 3) with EVI1 overexpression, supporting the rationale to further evaluate in vivo efficacy of birinapant and/or BETi-based combinations against this AML sub-type.

IAP antagonists such as SM-164, AT-406, and BV6, do not kill MDA-MB-231 cells alone, but allow LPS to induce cancer cell apoptosis rapidly. In summary, LPS sensitizes the therapeutic response of both triple-negative and ER breast cancer to IAP antagonist therapy by inducing rapid apoptosis of the cancer cells through TLR4- and MyD88-mediated production of TNFα. We conclude that antibiotics that can reduce microbiota-derived LPS should not be used together with an IAP antagonist for cancer therapy.

Immunofluorescence and western-blot results revealed that AZD5582- and SM-164-encapsulated liposomes facilitated mutual curative intensity, effectively triggered apoptosis of U87 MG and HBCSCs, reduced the expression of cellular IAP 1 (cIAP1) and X-linked IAP (XIAP), and enhanced the expression of caspase-3. Hence, RGV-Lf-liposomes carrying AZD5582 and SM-164 can be promising formulations to activate apoptosis of U87 MG and HBCSCs, and this functionalized drug delivery system targeting cIAP and XIAP is a potential strategy to cure glioblastoma in clinical cancer management.

SM-164 did not kill adriamycin-resistant BC cells, while adriamycin inhibited SM-164-resistant BC cell growth, similar to parental cells. We conclude that SM-164 is a promising therapeutic agent for early stage bone and lung metastasis from triple-negative breast cancer that should be given prior to conventional chemotherapy.

Molecular analysis detected a mutation in the NF1 gene [c.4084C > T, p.(Arg1362Ter)], 2 different pathogenic mutations in TP53 [c.742C > T, p.(Arg248Trp), AF:12%, COSM1640831 and c.528C > G, p.(Cys176Trp), AF:12%, COSM11114], and a mutation in GNAS [c.601C > T, p.(Arg201Cys), AF: 9%, COSM123397]. To the best of our knowledge, this is the first case reporting collagen rosettes and pseudoglandular features in primary cutaneous DM.