Light Neutralinos in B-Decays

We consider the decays of a $B_s$-meson into a pair of lightest supersymmetric particles (LSP) in the minimal supersymmetric standard model. It is found that the parameter space for light LSP's in the range of 1 GeV can be appreciably constrained by looking for such decays.Comment: 9 pages, LaTex, 2 figures (hard copies of the figures available from the Authors on request

Tau-Universality Violation with Light Neutralinos

In a supersymmetric model with the lightest supersymmetric particle (LSP) $\chi$ in the range of a few hundred MeV's, the decay $\tau {\longrightarrow} \mu \chi \chi$ is going to be allowed. We investigate the departure from tau-universality caused by this decay. It is found that the universality violation in this way can be greater than both non-universal electroweak radiative corrections and supersymmetric one-loop corrections over a considerable region of the parameter space allowed by experiments so far. Thus it suggests a method of constraining the parameter space with light LSP's using data from tau-factories.Comment: 11 pages, LATEX, 3 figures (hard copies of figures available from the Authors on request

Baryogenesis through R-parity violation

We consider generation of baryon asymmetry of the universe through $R-$parity violation in a scenario in which out-of-equilibrium condition is satisfied by making the electroweak phase transition to be first order. We study all the $R-$parity violating interaction which can generate $(B-L)$ asymmetry which then converts to baryon asymmetry of the universe. We demonstrate that CP--violating sfermion deudy all the $R-$parity violating interaction which can generate $(B-L)$ asymmetry which then converts to baryon asymmetry of the universe. We demonstrate that CP--violating sfermion decays contribute more than that of the neutralino decays in the generation of $(B-L)$ asymmetry.Comment: 25 pages latex file (containing six eps files

Abstract 2413: αEGFR-E-P125A antibody-endostatin fusion protein reduces vasculogenic mimicry and metastasis by inhibiting FAK, integrin, and EGFR signaling

Abstract Triple-Negative Breast Cancer (TNBC) is an aggressive subtype of breast cancer with high metastatic potential and increased morbidity and mortality. Although expression of, and signaling by the epidermal growth factor receptor (EGFR) is commonly seen in TNBC, anti-EGFR antibodies such as Cetuximab have had limited therapeutic efficacy, used either alone or in combination with chemotherapy. Primary TNBC tumor growth and metastases require supporting vasculature, which develops through a combination of endothelial angiogenesis and vasculogenic mimicry (VM). Our laboratory previously developed a novel targeted therapy, αEGFR-E-P125A, an antibody-endostatin fusion protein, by linking an anti-EGFR antibody targeting domain to a mutated version of the anti-angiogenic protein endostatin (E-P125A). αEGFR-E-P125A delivers a dimeric E-P125A payload which inhibits TNBC angiogenesis and VM in vitro and in vivo, and decreases metastatic tumor growth (lung metastasis) in both the MDA-MB-231-4175 and MDA-MB 468 TNBC xenograft models. Preliminary studies of the mechanism of αEGFR-E-P125A action indicate that αEGFR-E-P125A downregulates VM through combined inhibition of EGFR and integrin signaling. Phospho-array analysis of αEGFR-E-P125A treated MDA-MB-231-4175 cells demonstrated downregulation of phosphorylation of EGFR at Y1069, a site of aberrant EGFR signaling which promotes TNBC motility. The phospho-array also demonstrated inhibition of focal adhesion kinase (FAK) phosphorylation at Y397. FAK signaling occurs downstream of β1 and β3 integrins, and the Y397 site is implicated in the regulation of endothelial and TNBC motility, VM, and metastatic behavior. We specifically inhibited FAK at the Y397 site using a small molecule inhibitor, PF-573228, and demonstrated that FAK inhibition at Y397 alone inhibited the TNBC VM in vitro. shRNA-mediated knockdown of FAK in MDA-MB-231 TNBC cells confirmed that downregulation of FAK inhibited VM formation in vitro. Immunoprecipitation (IP) of EGFR detected the presence of β1 integrin, and IP of β1 integrin detected EGFR in both MDA-MB-231-4175 and MDA-MB-468 TNBC cells treated with αEGFR-E-P125A. αEGFR-E-P125A treatment increased levels of bound β1 integrin following IP of EGFR relative to untreated or Cetuximab treated TNBC cells. These results indicate that αEGFR-E-P125A is binding to both EGFR and β1 integrin simultaneously, suppressing downstream EGFR and integrin signaling. Simultaneous inhibition of EGFR and β1 integrin signaling by αEGFR-E-P125A fusion is a promising approach to inhibition of TNBC growth and metastases. Citation Format: Ankita P. Sankar, Hyun Mi Cho, Hava Gil-Henn, Sundaram Ramakrishnan, Rathin Das, Christian Elledge, Yu Zhang, Seung-Uon Shin, Joseph D. Rosenblatt. αEGFR-E-P125A antibody-endostatin fusion protein reduces vasculogenic mimicry and metastasis by inhibiting FAK, integrin, and EGFR signaling [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 2413

Antibody-drug conjugate αEGFR-E-P125A reduces triple-negative breast cancer vasculogenic mimicry, motility, and metastasis through inhibition of EGFR, integrin, and FAK/STAT3 signaling

Primary tumor growth and metastasis in triple-negative breast cancer (TNBC) require supporting vasculature, which develop through a combination of endothelial angiogenesis and vasculogenic mimicry (VM), a process associated with aggressive metastatic behavior in which vascular-like structures are lined by tumor cells. We developed αEGFR-E-P125A, an antibody-endostatin fusion protein that delivers a dimeric, mutant endostatin (E-P125A) payload that inhibits TNBC angiogenesis and VM in vitro and in vivo. To characterize the mechanisms associated with induction and inhibition of VM, RNA-seq of MDA-MB-231-4175 TNBC cells grown in a monolayer (2D) was compared to cells plated on Matrigel undergoing VM (3D). We then compared RNA-seq between TNBC cells in 3D and cells in 3D with VM inhibited by αEGFR-E-P125A (EGFR-E-P125A). Gene set enrichment analysis (GSEA) demonstrated that VM induction activated the IL6-JAK-STAT3 and angiogenesis pathways, which were downregulated by αEGFR-E-P125A treatment. Correlative analysis of the phospho-proteome demonstrated decreased EGFR phosphorylation at Y1069, along with decreased phosphorylation of focal adhesion kinase (FAK) Y397 and STAT3 Y705 sites downstream of α5β1 integrin. Suppression of phosphorylation events downstream of EGFR and α5β1 integrin demonstrated that αEGFR-E-P125A interferes with ligand-receptor activation, inhibits VM, and overcomes oncogenic signaling associated with EGFR and α5β1 integrin crosstalk. In vivo, αEGFR-E-P125A treatment decreased primary tumor growth and VM, reduced lung metastasis, and confirmed the inhibition of signaling events observed in vitro. Simultaneous inhibition of EGFR and α5β1 integrin signaling by αEGFR-E-P125A is a promising strategy for the inhibition of VM, tumor growth, motility, and metastasis in TNBC and other EGFR-overexpressing tumors

Inhibition of Vasculogenic Mimicry and Angiogenesis by an Anti-EGFR IgG1-Human Endostatin-P125A Fusion Protein Reduces Triple Negative Breast Cancer Metastases

Triple negative breast cancer (TNBC) is an aggressive breast cancer subtype with limited therapeutic options. Metastasis is the major cause of TNBC mortality. Angiogenesis facilitates TNBC metastases. Many TNBCs also form vascular channels lined by tumor cells rather than endothelial cells, known as ‘vasculogenic mimicry’ (VM). VM has been linked to metastatic TNBC behavior and resistance to anti-angiogenic agents. Epidermal growth factor receptor (EGFR) is frequently expressed on TNBC, but anti-EGFR antibodies have limited efficacy. We synthesized an anti-EGFR antibody–endostatin fusion protein, αEGFR IgG1-huEndo-P125A (αEGFR-E-P125A), designed to deliver a mutant endostatin, huEndo-P125A (E-P125A), to EGFR expressing tumors, and tested its effects on angiogenesis, TNBC VM, and motility in vitro, and on the growth and metastasis of two independent human TNBC xenograft models in vivo. αEGFR-E-P125A completely inhibited the ability of human umbilical vein endothelial cells to form capillary-like structures (CLS) and of TNBC cells to engage in VM and form tubes in vitro. αEGFR-E-P125A treatment reduced endothelial and TNBC motility in vitro more effectively than E-P125A or cetuximab, delivered alone or in combination. Treatment of TNBC with αEGFR-E-P125A was associated with a reduction in cytoplasmic and nuclear β-catenin and reduced phosphorylation of vimentin. αEGFR-E-P125A treatment of TNBC xenografts in vivo inhibited angiogenesis and VM, reduced primary tumor growth and lung metastasis of orthotopically implanted MDA-MB-468 TNBC cells, and markedly decreased lung metastases following intravenous injection of MDA-MB-231-4175 lung-tropic TNBC cells. Combined inhibition of angiogenesis, VM, and TNBC motility mediated by αEGFR-E-P125A is a promising strategy for the prevention of TNBC metastases