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Novel agents that downregulate EGFR, HER2, and HER3 in parallel.

Ferreira RB, Law ME, Jahn SC, Davis BJ, Heldermon CD, Reinhard M, Castellano RK, Law BK - Oncotarget (2015)

Bottom Line: These compounds disrupt disulfide bonds and are termed Disulfide Bond Disrupting Agents (DDAs).DDA RBF3 exhibits anticancer efficacy in vivo at 40 mg/kg without evidence of toxicity.DDAs may complement existing EGFR-, HER2-, and HER3-targeted agents that function through alternate mechanisms of action, and combination regimens with these existing drugs may overcome therapeutic resistance.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of Florida, Gainesville, FL 32611, USA.

ABSTRACT
EGFR, HER2, and HER3 contribute to the initiation and progression of human cancers, and are therapeutic targets for monoclonal antibodies and tyrosine kinase inhibitors. An important source of resistance to these agents arises from functional redundancy among EGFR, HER2, and HER3. EGFR family members contain conserved extracellular structures that are stabilized by disulfide bonds. Compounds that disrupt extracellular disulfide bonds could inactivate EGFR, HER2, and HER3 in unison. Here we describe the identification of compounds that kill breast cancer cells that overexpress EGFR or HER2. Cell death parallels downregulation of EGFR, HER2, and HER3. These compounds disrupt disulfide bonds and are termed Disulfide Bond Disrupting Agents (DDAs). DDA RBF3 exhibits anticancer efficacy in vivo at 40 mg/kg without evidence of toxicity. DDAs may complement existing EGFR-, HER2-, and HER3-targeted agents that function through alternate mechanisms of action, and combination regimens with these existing drugs may overcome therapeutic resistance.

No MeSH data available.


Related in: MedlinePlus

Identification of the Pharmacophore in EGFR/HER2/HER3-targeted CompoundsA. Photomicrographs of MDA-MB-468 cells treated for 24 hours with 20 μM of the indicated compounds. B. Immunoblot analysis of MDA-MB-468 cells treated as in (A) C. Chemical structures of Disulfide bond Disrupting Agents (DDAs) showing active compounds on the left side with the pharmacophore highlighted in red, along with the generic pharmacophore. Inactive compounds either lack the pharmacophore sulfinate or disulfide groups, or do not have the appropriate four-carbon spacer between these groups. The exception to this rule is NSC627175/DTDO, which represents a cyclic version of the pharmacophore. D. Viability of BT474 or MDA-MB-468 cells treated for 24 hours with the indicated drug at the specified concentrations was measured in MTT assays. E. Proliferation of tert-immortalized human mammary epithelial cells (HMEC-tert) and MDA-MB-468, BT474, and SKBR3 breast cancer cells after incubation with the indicated concentrations of RBF3 for 24 hours was measured in thymidine incorporation assays as described in Figure 1E. F–H. The indicated cell lines were treated with the specified compounds at 20 μM unless otherwise indicated for 24 hours and analyzed by immunoblot. Assays in (D) and (E) were carried out in triplicate and results were presented as the average ± S.D. Scale bars are 20 μm.
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Figure 4: Identification of the Pharmacophore in EGFR/HER2/HER3-targeted CompoundsA. Photomicrographs of MDA-MB-468 cells treated for 24 hours with 20 μM of the indicated compounds. B. Immunoblot analysis of MDA-MB-468 cells treated as in (A) C. Chemical structures of Disulfide bond Disrupting Agents (DDAs) showing active compounds on the left side with the pharmacophore highlighted in red, along with the generic pharmacophore. Inactive compounds either lack the pharmacophore sulfinate or disulfide groups, or do not have the appropriate four-carbon spacer between these groups. The exception to this rule is NSC627175/DTDO, which represents a cyclic version of the pharmacophore. D. Viability of BT474 or MDA-MB-468 cells treated for 24 hours with the indicated drug at the specified concentrations was measured in MTT assays. E. Proliferation of tert-immortalized human mammary epithelial cells (HMEC-tert) and MDA-MB-468, BT474, and SKBR3 breast cancer cells after incubation with the indicated concentrations of RBF3 for 24 hours was measured in thymidine incorporation assays as described in Figure 1E. F–H. The indicated cell lines were treated with the specified compounds at 20 μM unless otherwise indicated for 24 hours and analyzed by immunoblot. Assays in (D) and (E) were carried out in triplicate and results were presented as the average ± S.D. Scale bars are 20 μm.

Mentions: The anticancer effects of the Disulfide bond Disrupting Agents (DDAs) were discovered serendipitously. Our initial goal was to employ molecular docking and a homology model of the CUB Domain-Containing Protein 1 (CDCP1) to identify compounds that would modulate CDCP1 tyrosine phosphorylation. During this screening, we noticed that compound NSC624205 killed the MDA-MB-468 cells used in the screen when administered at 20 μM for 24 h, while none of the other structurally unrelated compounds tested had this effect. Another cell line used in the initial screens, the BxPC3 pancreatic cell line, was unaffected by the same treatment. Therefore we were intrigued by the selective actions of NSC624205 against MDA-MB-468 cells, but not BxPC3 cells, and endeavored to identify the underlying molecular basis. NSC624205 (structure shown in Figure 4C) contains a sulfinic acid moiety, and the sulfur atom in sulfinic acids can act as a nucleophile with the potential to break disulfide bonds.


Novel agents that downregulate EGFR, HER2, and HER3 in parallel.

Ferreira RB, Law ME, Jahn SC, Davis BJ, Heldermon CD, Reinhard M, Castellano RK, Law BK - Oncotarget (2015)

Identification of the Pharmacophore in EGFR/HER2/HER3-targeted CompoundsA. Photomicrographs of MDA-MB-468 cells treated for 24 hours with 20 μM of the indicated compounds. B. Immunoblot analysis of MDA-MB-468 cells treated as in (A) C. Chemical structures of Disulfide bond Disrupting Agents (DDAs) showing active compounds on the left side with the pharmacophore highlighted in red, along with the generic pharmacophore. Inactive compounds either lack the pharmacophore sulfinate or disulfide groups, or do not have the appropriate four-carbon spacer between these groups. The exception to this rule is NSC627175/DTDO, which represents a cyclic version of the pharmacophore. D. Viability of BT474 or MDA-MB-468 cells treated for 24 hours with the indicated drug at the specified concentrations was measured in MTT assays. E. Proliferation of tert-immortalized human mammary epithelial cells (HMEC-tert) and MDA-MB-468, BT474, and SKBR3 breast cancer cells after incubation with the indicated concentrations of RBF3 for 24 hours was measured in thymidine incorporation assays as described in Figure 1E. F–H. The indicated cell lines were treated with the specified compounds at 20 μM unless otherwise indicated for 24 hours and analyzed by immunoblot. Assays in (D) and (E) were carried out in triplicate and results were presented as the average ± S.D. Scale bars are 20 μm.
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Related In: Results  -  Collection

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Figure 4: Identification of the Pharmacophore in EGFR/HER2/HER3-targeted CompoundsA. Photomicrographs of MDA-MB-468 cells treated for 24 hours with 20 μM of the indicated compounds. B. Immunoblot analysis of MDA-MB-468 cells treated as in (A) C. Chemical structures of Disulfide bond Disrupting Agents (DDAs) showing active compounds on the left side with the pharmacophore highlighted in red, along with the generic pharmacophore. Inactive compounds either lack the pharmacophore sulfinate or disulfide groups, or do not have the appropriate four-carbon spacer between these groups. The exception to this rule is NSC627175/DTDO, which represents a cyclic version of the pharmacophore. D. Viability of BT474 or MDA-MB-468 cells treated for 24 hours with the indicated drug at the specified concentrations was measured in MTT assays. E. Proliferation of tert-immortalized human mammary epithelial cells (HMEC-tert) and MDA-MB-468, BT474, and SKBR3 breast cancer cells after incubation with the indicated concentrations of RBF3 for 24 hours was measured in thymidine incorporation assays as described in Figure 1E. F–H. The indicated cell lines were treated with the specified compounds at 20 μM unless otherwise indicated for 24 hours and analyzed by immunoblot. Assays in (D) and (E) were carried out in triplicate and results were presented as the average ± S.D. Scale bars are 20 μm.
Mentions: The anticancer effects of the Disulfide bond Disrupting Agents (DDAs) were discovered serendipitously. Our initial goal was to employ molecular docking and a homology model of the CUB Domain-Containing Protein 1 (CDCP1) to identify compounds that would modulate CDCP1 tyrosine phosphorylation. During this screening, we noticed that compound NSC624205 killed the MDA-MB-468 cells used in the screen when administered at 20 μM for 24 h, while none of the other structurally unrelated compounds tested had this effect. Another cell line used in the initial screens, the BxPC3 pancreatic cell line, was unaffected by the same treatment. Therefore we were intrigued by the selective actions of NSC624205 against MDA-MB-468 cells, but not BxPC3 cells, and endeavored to identify the underlying molecular basis. NSC624205 (structure shown in Figure 4C) contains a sulfinic acid moiety, and the sulfur atom in sulfinic acids can act as a nucleophile with the potential to break disulfide bonds.

Bottom Line: These compounds disrupt disulfide bonds and are termed Disulfide Bond Disrupting Agents (DDAs).DDA RBF3 exhibits anticancer efficacy in vivo at 40 mg/kg without evidence of toxicity.DDAs may complement existing EGFR-, HER2-, and HER3-targeted agents that function through alternate mechanisms of action, and combination regimens with these existing drugs may overcome therapeutic resistance.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of Florida, Gainesville, FL 32611, USA.

ABSTRACT
EGFR, HER2, and HER3 contribute to the initiation and progression of human cancers, and are therapeutic targets for monoclonal antibodies and tyrosine kinase inhibitors. An important source of resistance to these agents arises from functional redundancy among EGFR, HER2, and HER3. EGFR family members contain conserved extracellular structures that are stabilized by disulfide bonds. Compounds that disrupt extracellular disulfide bonds could inactivate EGFR, HER2, and HER3 in unison. Here we describe the identification of compounds that kill breast cancer cells that overexpress EGFR or HER2. Cell death parallels downregulation of EGFR, HER2, and HER3. These compounds disrupt disulfide bonds and are termed Disulfide Bond Disrupting Agents (DDAs). DDA RBF3 exhibits anticancer efficacy in vivo at 40 mg/kg without evidence of toxicity. DDAs may complement existing EGFR-, HER2-, and HER3-targeted agents that function through alternate mechanisms of action, and combination regimens with these existing drugs may overcome therapeutic resistance.

No MeSH data available.


Related in: MedlinePlus