ABSTRACT
New molecular markers of cancer had emerged with novel applications in cancer prevention and therapeutics, including for breast cancer of unknown causes, which has a high impact on the health of women worldwide. The purpose of this research was to determine protein and mRNA expression of synaptic vesicle 2 (SV2) isoforms A, B and C in breast cancer cell lines. Cultured cell lines MDA-MB-231, SKBR3, T47D were lysed and their protein and mRNA expression analyzed by real-time PCR and western blot technique, respectively. SV2A, B proteins were identified in non-tumor (MCF-10A) and tumor cell lines (MDA-MB-231 and T47D) while SV2C only was found in the T47D cell line. Furthermore, the genomic expression was consistent with protein expression for a such cell line, but in MDA-MB-231 there was no SV2B genomic expression, and the SV2C mRNA and protein were not found in the non tumoral cell line. These findings suggest a possible cellular transdifferentiation to neural character in breast cancer, of possible relevance to cancer development, and point to possible use of SV2 as molecular marker and a vehicle for cancer treatment with botulinum toxin.
Subject(s)
Breast Neoplasms/metabolism , Breast/metabolism , Membrane Glycoproteins/metabolism , Nerve Tissue Proteins/metabolism , Blotting, Western , Breast Neoplasms/genetics , Cells, Cultured , Female , Humans , Membrane Glycoproteins/genetics , Nerve Tissue Proteins/genetics , Protein Isoforms , RNA, Messenger/genetics , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
Actin cytoskeleton disruption in host cells has been demonstrated for PTPases from pathogenic microorganisms. In this work, we analysed whether the secreted acid phosphatase from Entamoeba histolytica has phosphotyrosine phosphatase activity and the possibility that this activity may participate in damaging host cells. The secreted acid phosphatase of E. histolytica, which catalyses p-nitrophenyl phosphate hydrolysis at acid pH values, was found to have phosphotyrosine phosphatase activity. The enzymatic properties of phosphotyrosine phosphatase and acid phosphatase were virtually identical and included: Km values of 10 x 10(-4) M, no requirement for divalent cations, and sensitivity to molybdate, vanadate, and tungstate. The phosphotyrosyl phosphatase activity caused significant levels of cell rounding and detachment correlating with disruption of the actin stress fibres in HeLa cells. Thus, our data suggest that secreted phosphotyrosine phosphatase could play a cytotoxic role during amoebic infection.