The pathological presence of tissue factor (TF) in cancer cells promotes tumor-initiated thrombosis and cancer metastasis. We found that TF is aberrantly present in large percentage of aggressive triple negative breast cancer (TNBC) and pancreatic adenocarcinoma (PaC), two most lethal forms of malignancy that urgently need effective treatment. TF expression in TNBC clustered with higher levels of vimentin, basal-type keratins KRT5/14 and caveolin-1 but lower levels of luminal-type biomarkers. We developed a novel and specific anti-TF therapeutic antibody SC1, which displayed an exceedingly high potency against TF extracellular domain (EC50: 0.019 nM), TF-positive TNBC- or PaC cells (EC50: 2.5 nM), intracellular protease activated receptor 2 (PAR2) signaling (IC50: 2-3 nM) and tumor-initiated coagulation (IC50: <10 nM). Depletion of TF or SC1-treatment in TNBC or PaC cells inhibited TF-induced cell migration, lung metastasis and tumor growth in vivo, accompanied by diminished levels of tumor angiogenesis and stromal fibrosis. We further propose TF as a promising target for antibody-drug conjugate (ADC) development based on its rapid and efficient internalization of SC1-drug conjugate. Both SC1-DM1 and SC1-MMAE elicited exquisite cytotoxicity in TF-positive TNBC and PaC cells (IC50: 0.02-0.1 nM) but not in TF-negative cells (>100 nM) achieving >5000 fold target selectivity. Following a weekly intravenous administration, SC1-MMAE and its humanized hSC1-MMAE inhibited TNBC- and PaC tumor growth achieving MED of 0.3-1 mg/kg and were both well tolerated. Thus, the prevalent TF expression in TNBC and PaC renders these challenging tumors highly susceptible to TF-targeted treatment and may offer new opportunity in cancer patients.
The G protein-coupled receptor (GPCR) smoothened (SMO) is a key signaling component of the sonic hedgehog (Hh) pathway and a clinically validated target for cancer treatment. The FDA-approved SMO inhibitors GDC-0449/Vismodegib and LDE225/Sonidegib demonstrated clinical antitumor efficacy. Nevertheless, relatively high percentage of treated patients would eventually develop acquired cross resistance to both drugs. Here, based on published structure and activity of GDC-0449 inhibitor class, we replaced its amide core with benzimidazole which retained bulk of the SMO-targeting activity as measured in our Hh/SMO/Gli1-reporter system. Synthesis and screening of multiple series of benzimidazole derivatives identified HH-1, HH-13, and HH-20 with potent target suppression (IC: <0.1 μmol/L) in the reporter assays. In NIH3T3 cells stimulated with a secreted Hh (SHH), these inhibitors dose dependently reduced mRNA and protein expression of the endogenous pathway components PTCH-1, Gli1, and cyclin D1 resulting in growth inhibition via G/G arrest. Mechanistically, the SMO-targeted growth inhibition involved downregulation of mTOR signaling inputs and readouts consistent with diminished mTORC1/mTORC2 functions and apoptosis. In mice, as with GDC-0449, orally administered HH inhibitors blocked paracrine activation of stromal Hh pathway in Calu-6 tumor microenvironment and attenuated growth of PTCH/P53 medulloblastoma allograft tumors. Furthermore, HH-13 and HH-20 potently targeted the drug-resistant smoothened SMO-D473H (IC: <0.2 μmol/L) compared to the poor inhibition by GDC-0449 (IC: >60 μmol/L). These results identify HH-13 and HH-20 as potent inhibitors capable of targeting naïve and drug-resistant Hh/SMO-driven cancers. The current leads may be optimized to improve pharmaceutical property for potential development of new therapy for treatment of Hh pathway-driven cancers.
Mechanistic target of rapamycin (mTOR) signaling pathway mediates the function of oncogenic receptor tyrosine kinases (RTKs). We aimed to elucidate new role of mTOR in EGFR-mutant (EGFR-mut) non-small cell lung cancer (NSCLC) and glioblastoma (GBM) with a focus on tumor microenvironments. Here, we report a novel regulatory link between mTOR complexes (mTORCs) and tissue factor (TF), an initiator of tumorderived thrombosis. TF is elevated in EGFR-mut NSCLC/GBM cell lines and tumors from patients with poor prognosis. Application of mTORC1/2 inhibitors (AZD8055, WYE-125132, MTI-31, and rapamycin) or genetic mTORC-depletion all reduced TF expression, which appeared to be differentially mediated depending on cellular context. In U87MG and HCC827 cells, mTORC1 exerted a dominant role via promoting TF mRNA transcription. In EGFR-TKI-resistant H1975 and PC9 cells, it was mTORC2 that played a major role in specific repression of lysosomal-targeted TF protein degradation. Successful inhibition of TF expression was demonstrated in AZD8055-or MTI-31treated H1975 and U87MG tumors in mice, while a TF-targeted antibody antagonized TF activity without reducing TF protein. Both the mTOR-and TF-targeted therapy induced a multifaceted remodeling of tumor microenvironment reflecting not only a diminished hypercoagulopathy state (fibrin level) but also a reduced stromal fibrosis (collagen distribution), compromised vessel density and/or maturity (CD31 and/or α-SMA) as well as a substantially decreased infiltration of immune-suppressive M2-type tumor-associated macrophages (CD206/F4/80 ratio). Thus, our results have identified TF as a functional biomarker of mTOR. Downregulation of mTOR-TF axis activity likely contributes to the therapeutic mechanism of mTORC1/2-and TF-targeted agents in EGFR-mut advanced NSCLC and GBM.
IL-33, the ligand for ST2, is a member of IL-1 family. IL-33 was described to activate many immune cell types involved in type-2 immunity and allergic inflammation. Here we describe a novel anti-IL33 humanized monoclonal antibody, SSGJ-621, which bound IL-33 with high affinity and blocked the interaction between IL-33 and ST2. Our study has shown that SSGJ-621 was capable of effectively neutralizing IL-33-induced IL-6 secretion from HUVECs and IL-33-dependent IFNγ production in PBMCs and NK cells, suggesting a role that IL-33 might be involved in Th1-type of immunity. In addition, SSGJ-621 also exhibited potent inhibitory effects on IL-33 induced IL-5 and IL-13 production in KU812 cells. In vivo study demonstrated that SSGJ-621 can inhibit the activation of splenocytes in spleen and the production of eosinophils and IL-5 in peripheral blood. Thereby, our results highlight the dual functions of IL-33 in promoting Th1 and Th2 immune responses and SSGJ-621 has potentials to treat not only chronic inflammatory diseases induced by IL-33, but also cancers by favoring Th1 antitumor immunity in the tumor microenvironment. Citation Format: Xuesai Zhang, Qingrou Li, Cui Liu, Le Zhao, Lujie Wang, Lan Deng, Wei Xu, Hongli song, Zhenping Zhu, Haomin Huang. A novel anti-IL33 antibody that neutralized Th1-type and Th2-type pro-inflammation responses induced by IL-33/ST2 axis pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6191.
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