BCA101 Is a Tumor-Targeted Bifunctional Fusion Antibody That Simultaneously Inhibits EGFR and TGFß Signaling to Durably Suppress Tumor Growth.

The EGFR and TGFß signaling pathways are important mediators of tumorigenesis, and cross-talk between them contributes to cancer progression and drug resistance. Therapies capable of simultaneously targeting EGFR and TGFß could help improve patient outcomes across various cancer types. Here, we developed BCA101, an anti-EGFR IgG1 mAb linked to an extracellular domain of human TGFßRII. The TGFß "trap" fused to the light chain in BCA101 did not sterically interfere with its ability to bind EGFR, inhibit cell proliferation, or mediate antibody-dependent cellular cytotoxicity. Functional neutralization of TGFß by BCA101 was demonstrated by several in vitro assays. BCA101 increased production of proinflammatory cytokines and key markers associated with T-cell and natural killer-cell activation, while suppressing VEGF secretion. In addition, BCA101 inhibited differentiation of naïve CD4+ T cells to inducible regulatory T cells (iTreg) more strongly than the anti-EGFR antibody cetuximab. BCA101 localized to tumor tissues in xenograft mouse models with comparable kinetics to cetuximab, both having better tumor tissue retention over TGFß "trap." TGFß in tumors was neutralized by approximately 90% in animals dosed with 10 mg/kg of BCA101 compared with 54% in animals dosed with equimolar TGFßRII-Fc. In patient-derived xenograft mouse models of head and neck squamous cell carcinoma, BCA101 showed durable response after dose cessation. The combination of BCA101 and anti-PD1 antibody improved tumor inhibition in both B16-hEGFR-expressing syngeneic mouse models and in humanized HuNOG-EXL mice bearing human PC-3 xenografts. Together, these results support the clinical development of BCA101 as a monotherapy and in combination with immune checkpoint therapy. SIGNIFICANCE: The bifunctional mAb fusion design of BCA101 targets it to the tumor microenvironment where it inhibits EGFR and neutralizes TGFß to induce immune activation and to suppress tumor growth.

Correction: T cell activation and differentiation is modulated by a CD6 domain 1 antibody Itolizumab.

[This corrects the article DOI: 10.1371/journal.pone.0180088.].

T cell activation and differentiation is modulated by a CD6 domain 1 antibody Itolizumab.

CD6 is associated with T-cell modulation and is implicated in several autoimmune diseases. We previously demonstrated that Itolizumab, a CD6 domain 1 (CD6D1) specific humanized monoclonal antibody, inhibited the proliferation and cytokine production by T lymphocytes stimulated with anti-CD3 antibody or when co-stimulated with ALCAM. Aberrant IL-17 producing CD4+ helper T-cells (Th17) have been identified as pivotal for the pathogenesis of certain inflammatory autoimmune disorders, including psoriasis. Itolizumab has demonstrated efficacy in human diseases known to have an IL-17 driven pathogenesis. Here, in in vitro experiments we show that by day 3 of human PBMC activation using anti-CD3 and anti-CD28 co-stimulation in a Th17 polarizing milieu, 15-35% of CD4+ T-cells overexpress CD6 and there is an establishment of differentiated Th17 cells. Addition of Itolizumab reduces the activation and differentiation of T cells to Th17 cells and decreases production of IL-17. These effects are associated with the reduction of key transcription factors pSTAT3 and RORγT. Further, transcription analysis studies in these conditions indicate that Itolizumab suppressed T cell activation by primarily reducing cell cycle, DNA transcription and translation associated genes. To understand the mechanism of this inhibition, we evaluated the effect of this anti-human CD6D1 mAb on ALCAM-CD6 as well as TCR-mediated T cell activation. We show that Itolizumab but not its F(ab')2 fragment directly inhibits CD6 receptor hyper-phosphorylation and leads to subsequent decrease in associated ZAP70 kinase and docking protein SLP76. Since Itolizumab binds to CD6 expressed only on human and chimpanzee, we developed an antibody binding specifically to mouse CD6D1. This antibody successfully ameliorated the incidence of experimental autoimmune encephalitis in the mice model. These results position CD6 as a key molecule in sustaining the activation and differentiation of T cells and an important target for modulating autoimmune diseases.

Chemoprevention of familial adenomatous polyposis by bromo-noscapine (EM011) in the Apc(Min/+) mouse model.

Germline mutation of the tumor suppressor gene, adenomatous polyposis coli (APC), is responsible for familial adenomatous polyposis (FAP) with nearly 100% risk for colon cancer at an early age. Although FAP is involved in only 1% of all colon cancer cases, over 80% of sporadic cancers harbor somatic mutations of APC. We show here that bromo-noscapine (EM011), a rationally designed synthetic derivative of a natural nontoxic tubulin-binding alkaloid-noscapine, that reduces the dynamics of microtubules, causes a reversible G(2) /M arrest in wild type murine embryonic fibroblasts (MEFs), but an aberrant exit from a brief mitotic block, followed by apoptosis in MEFs after APC deletion with small interfering RNA. Furthermore, both ß-catenin levels and activity fell to half the original levels with a concomitant reduction of cell proliferation-inducing cyclin D1, c-Myc, and induction of cytostatic protein p21 before caspase-3 activation. Additionally, we show a statistically significant reduction in the number of newly emerging intestinal polyps (to 35% compared with untreated mice) as well as the mean size of polyps (to 42% compared with untreated mice) in EM011-treated Apc(Min/+) mice as compared to their sham-treated control littermates. The remaining polyps in the EM011 treated group of Apc(Min/+) mice showed evidence of elevated apoptosis as revealed by immunohistochemistry. We failed to detect any evidence of histopathological and hematological toxicities following EM011 treatment. Taken together, our data are persuasive that a clinical trial of EM011 is possible for the prevention/amelioration of polyposis in FAP patients.

Recent patents reveal microtubules as persistent promising target for novel drug development for cancers.

Conventionally, the successful targets for the drug development in cancer range from the DNA damage, replication, signal transduction pathways, hormones, cytokines, anti-angiogenic agents, and radio/photo-sensitizers. They dominate the therapeutic arena after the initial debulking surgery. More recently, tubulin, the primary constituent of microtubules (MTs), has made a fairly successful debut in the therapeutic armamentarium. Tubulin binding drugs come in two classes: that depolymerize microtubules and that over-polymerize and bundle them. Microtubule (MT) binding drugs are in some ways superior in nature primarily because of their less debilitating side effects when compared to the generalized DNA metabolism targeting agents, and many new promising patents are being funneled into the drug development pipeline. Nevertheless, many of these relatively new agents still face challenges relating to their delivery methods, bioavailability, toxicities, and the inevitable resistance shared by all chemotherapeutics. Finally, we disclose a new genre of anti-MT drugs, noscapinoids that have just begun climbing the clinical trials ladder. The lead compound, noscapine, is a plant derived, orally available, minimally-toxic (if at all) agent that has shown phenomenal promise in the preclinical experimentation and Phase-I clinical trial. A rational approach based upon the precise molecular model of the tubulin-noscapine complex is bound to inspire novel and better therapeutic analogs in future.

MK2: a novel molecular target for anti-inflammatory therapy.

BACKGROUND: Mitogen-activated protein kinase (MAPK)-activated protein kinase 2 (MK2) is activated upon stress by p38 MAPK. MK2 is stimulated in a wide range of inflammatory conditions and its catalytic activity is required for cytokine production, cell migration and is a potential drug target for inflammatory diseases. Disruption of MK2 leads to a reduction in TNF-alpha production. MK2-mediated pro-inflammatory cytokine production has been demonstrated in several inflammatory conditions where TNF-alpha plays a role. OBJECTIVE/METHODS: We discuss the development of specific MK2 inhibitors for the treatment of inflammatory diseases. RESULTS/CONCLUSION: Inhibition of the p38 MAPK pathway may have therapeutic uses for inflammatory diseases. However, blocking p38 MAPK activation in vivo is not advisable due to toxicity, significant off-target effects, and lack of oral bioavailability. This concern may be countered by the use of MK2 inhibitors that can dissect the pathways downstream of p38 without affecting additional cellular functions.

Molecular targeting of E3 ligases--a therapeutic approach for cancer.

BACKGROUND: The ubiquitin-proteasomal degradation pathway plays a critical role in protein degradation and regulates a wide variety of cellular functions. This highly conserved post-translational modification of proteolytic processes is mainly carried out by substrate-specific E3 ligases. The deregulation of E3 ligases contributes to cancer development and their overexpression is often associated with poor prognosis. OBJECTIVES: We review the current understanding of E3 ligases, their functional role in cancer pathogenesis, current progress and development of certain ubiquitin E3 ligases as targets for therapeutic intervention. METHODS: Preclinical and clinical data for E3 ligase inhibitors available in the public domain are discussed. CONCLUSIONS: With the growing understanding of their role in cancer development and progression, E3 ligases have emerged as potential anticancer targets for therapeutic intervention.

Enhanced soluble production of biologically active recombinant human p38 mitogen-activated-protein kinase (MAPK) in Escherichia coli.

The conditions were optimized for maximum soluble yield of biologically active recombinant p38alpha mitogen activated protein kinase (MAPK) vis-à-vis insoluble fraction (inclusion body formation). This study reports a rapid, economical and single step purification process for the overproduction of GST tagged p38alpha MAPK. A yield of 18 mg of highly purified and soluble protein per liter of bacterial culture within 6 h timeframe was achieved. The purified protein was found to be biologically suitable for phosphorylation by upstream kinases and was catalytically active. We further demonstrated that our in-house p38alpha MAPK is more potent (>30%) than a commercially available enzyme.