ABSTRACT
No disponible
Subject(s)
Female , Humans , Male , bcl-2-Associated X Protein/administration & dosage , bcl-2-Associated X Protein , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/radiotherapy , Apoptosis/genetics , Chromosomes/genetics , bcl-2-Associated X Protein/deficiency , bcl-2-Associated X Protein/metabolism , Colorectal Neoplasms/pathology , Colorectal Neoplasms/therapy , Phenotype , Apoptosis/physiology , Chromosomes/classificationABSTRACT
Metastasis accounts for most deaths from breast cancer, driving the need for new therapeutics that can impede disease progression. Rationally designed peptides that take advantage of cancer-specific differences in cellular physiology are an emerging technology that offer promise as a treatment for metastatic breast cancer. We developed CT20p, a hydrophobic peptide based on the C terminus of Bax that exhibits similarities with antimicrobial peptides, and previously reported that CT20p has unique cytotoxic actions independent of full-length Bax. In this study, we identified the intracellular actions of CT20p which precede cancer cell-specific detachment and death. Previously, we found that CT20p migrated in the heavy membrane fractions of cancer cell lysates. Here, using MDA-MB-231 breast cancer cells, we demonstrated that CT20p localizes to the mitochondria, leading to fusion-like aggregation and mitochondrial membrane hyperpolarization. As a result, the distribution and movement of mitochondria in CT20p-treated MDA-MB-231 cells was markedly impaired, particularly in cell protrusions. In contrast, CT20p did not associate with the mitochondria of normal breast epithelial MCF-10A cells, causing little change in the mitochondrial membrane potential, morphology or localization. In MDA-MB-231 cells, CT20p triggered cell detachment that was preceded by decreased levels of α5ß1 integrins and reduced F-actin polymerization. Using folate-targeted nanoparticles to encapsulate and deliver CT20p to murine tumors, we achieved significant tumor regression within days of peptide treatment. These results suggest that CT20p has application in the treatment of metastatic disease as a cancer-specific therapeutic peptide that perturbs mitochondrial morphology and movement ultimately culminating in disruption of the actin cytoskeleton, cell detachment, and loss of cell viability.
Subject(s)
Actin Cytoskeleton/drug effects , Antineoplastic Agents/pharmacology , Breast Neoplasms/drug therapy , Cell Adhesion/drug effects , Mitochondria/drug effects , Peptide Fragments/pharmacology , bcl-2-Associated X Protein/pharmacology , Actin Cytoskeleton/metabolism , Actin Cytoskeleton/pathology , Animals , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/metabolism , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Cell Death/drug effects , Cell Line, Tumor , Cell Survival/drug effects , Drug Carriers , Female , Folic Acid/metabolism , Humans , Membrane Potential, Mitochondrial/drug effects , Mice , Mice, Nude , Mitochondria/metabolism , Mitochondria/pathology , Mitochondrial Dynamics/drug effects , Nanoparticles , Peptide Fragments/administration & dosage , Peptide Fragments/metabolism , Time Factors , Tumor Burden/drug effects , Xenograft Model Antitumor Assays , bcl-2-Associated X Protein/administration & dosage , bcl-2-Associated X Protein/metabolismABSTRACT
Many approaches have so far been tried to enhance the immunogenicity of DNA vaccine. These include the use of various factors that induce apoptosis or anti-apoptosis effects when co-delivered with DNA vaccine. In the present study, the effects of pro-apoptotic Bax encoding plasmid (pBax) and anti-apoptotic Bcl-X(L) encoding plasmid (pBcl-xl), intradermally co-injected with glycoprotein B (gB) of Herpes Simplex Virus (HSV)-1 encoding plasmid (pgB) into the C57BL/6 mice were evaluated. Immune responses of the mice to the antigen were assessed by antibody assay, lymphoproliferative responses as well as cytokine and cytotoxic T-lymphocyte (CTL) assay. Analysis of the humoral and cellular responses showed that the mice immunized with pBax and pgB induced higher levels of antibody and Interleukin-4 as well as stronger lymphocyte proliferative responses and cytotoxic activity compared to those mice received pgB alone. pBcl-xl when intradermally co-injected with pgB showed no significant enhancement in immune responses comparing to pgB.
