Pancreatic adenocarcinoma (PDAC) is highly resistant to conventional chemotherapeutic interventions, resulting in exceptionally low survival rates. The limited efficacy can in part be attributed to... Show morePancreatic adenocarcinoma (PDAC) is highly resistant to conventional chemotherapeutic interventions, resulting in exceptionally low survival rates. The limited efficacy can in part be attributed to dose limitations and treatment cessation urged by toxicity of currently used chemotherapy. The advent of targeted delivery strategies has kindled hope for circumventing off-target toxicity. We have previously reported a PDAC-specific mesoporous silica nanoparticle (MSN) containing a protease linker responsive to ADAM9, a PDAC-enriched extracellularly deposited protease. Upon loading with paclitaxel these ADAM9-MSNs reduced side effects both in vitro and in vivo, however, disappointing antitumor efficacy was observed in vivo. Here, we propose that an efficient uptake of MSNs by tumor cells might underlie the lack of antitumor efficacy of MSNs functionalized with linker responsive to extracellular proteases. Harnessing this premise to improve antitumor efficacy, we performed an in silico analysis to identify PDAC-enriched intracellular proteases. We report the identification of BACE2, CAPN2 and DPP3 as PDAC enriched intracellular proteases, and report the synthesis of BACE2-, CAPN2- and DPP3- responsive MSNs. Extensive preclinical assessments revealed that paclitaxel-loaded CAPN2- and DPP3-MSNs exhibit high PDAC specificity in vitro as opposed to free paclitaxel. The administration of paclitaxel-loaded CAPN2- and DPP3-MSNs in vivo confirmed the reduction of leukopenia and induced no organ damage. Promisingly, in two mouse models CAPN2-MSNs reduced tumor growth at least as efficiently as free paclitaxel. Taken together, our results pose CAPN2-MSNs as a promising nanocarrier for the targeted delivery of chemotherapeutics in PDAC. Show less
TGF beta-SMAD3 signaling is a major driving force for cancer metastasis, while BMP-SMAD1/5 signaling can counteract this response. Analysis of gene expression profiles revealed that an increased... Show moreTGF beta-SMAD3 signaling is a major driving force for cancer metastasis, while BMP-SMAD1/5 signaling can counteract this response. Analysis of gene expression profiles revealed that an increased TGF beta-SMAD3 and a reduced BMP-SMAD1/5 targeted gene expression signature correlated with shortened distant metastasis free survival and overall survival of patients. At molecular levels, we discovered that TGF beta abolished BMP-induced SMAD1/5 activation in the highly-invasive breast cancer MDA-MB-231 cells, but to a less extent in the non-invasive cancer and normal breast cells. This suggests an inverse correlation between BMP signaling and invasiveness of tumor cells and TGF beta signaling acts in a double whammy fashion in driving cancer invasion and metastasis. Sustained ERK activation by TGF beta was specifically observed in MDA-MB-231 cells, and MEK inhibitor (MEKi) treatment restored BMP-SMAD1/5 signaling while not affecting SMAD2/3 activation. FK506 potently activated BMP, but not TGF beta signaling in breast cancer cells. MEKi or FK506 alone inhibited MDA-MB-231 extravasation in a zebrafish xenograft cancer model. Importantly, when administrated at suboptimal concentrations MEKi and FK506 strongly synergized in promoting BMP-SMAD1/5 signaling and inhibiting cancer cell extravasation. Furthermore, this combination of suboptimal concentrations treatment in a mouse tumor model resulted in real-time reduction of BMP-SMAD1/5 signaling in live tumors, and consequently potently inhibited tumor self-seeding, liver and bone metastasis, but not lung and brain metastasis. Mechanistically, it is the first time to identify BMP-SMAD1/5 signaling as an underlying molecular driver for organ-specific metastasis. Combining of MEKi and FK506, or their analogues, may be explored for clinical development of breast cancer. Show less
A few founder BRCA1 mutations (5382insC 4154delA 185delAG) account for up to 15% of high-risk (young-onset or familial or bilateral) breast cancer (BC) cases in Russia The impact of non founder... Show moreA few founder BRCA1 mutations (5382insC 4154delA 185delAG) account for up to 15% of high-risk (young-onset or familial or bilateral) breast cancer (BC) cases in Russia The impact of non founder BRCA1 mutations in this country is less studied in particular there are no reports analyzing gross rearrangements of this gene in the Russian patient series We selected for the study 95 founder mutation negative high-risk BC cases Combination of high-resolution melting (HRM) and sequencing revealed six presumably BC-associated alleles (2080delA, 4808C > G 5214C > T 5236G > A 5460G > T 5622C > T) and one variant of an unknown significance (4885G > A) The pathogenic role of the 5236G > A mutation leading to G1 706E substitution was further confirmed by the loss of heterozygosity analysis of the corresponding tumor tissue Multiplex ligation-dependent probe amplification (MLPA) revealed two additional BRCA1 heterozygotes which carried BRCA1 deletions involving exons 1-2 and 3-7 respectively Based on the results of this investigation and the review of prior Russian studies three BRCA1 mutations (2080delA 3819de15 3875del4) were considered with respect to their possible founder effect and tested in the additional series of 210 high-risk BC patients two BACA heterozygotes (2080delA and 3819de15) were revealed We conclude that the non-founder mutations constitute the minority of BRCA1 defects in Russia (C) 2010 Elsevier Ireland Ltd All rights reserved Show less
A newly developed assay based on chemically induced premature chromosome condensation (PCC) and multi-color combined binary ratio labeling (COBRA) fluorescence in situ hybridization (FISH)... Show moreA newly developed assay based on chemically induced premature chromosome condensation (PCC) and multi-color combined binary ratio labeling (COBRA) fluorescence in situ hybridization (FISH) techniques have been implemented in order to investigate for the first time for recurrent cytogenetic aberrations in primary cervical carcinoma (derived directly from biopsies) at different stages of progression. The cytogenetic profiles of 17 biopsies derived from 14 and 3 cervical cancer patients with squamous-cell carcinomas (Sq) and with adenocarcinomas (Ad), respectively, were assessed. Frequencies of both structural as well as numerical aberrations were found to be higher in Sq than in Ad. The analysis revealed that even in early tumors stages (IB1) have a higher frequency of chromosome-losses and -gains as well as chromosomal alterations as compared to normal cells. A positive trend was found between stage advancement of cervical tumors and the frequency of numerical and structural aberrations. No specific and common chromosomal abnormality (e.g. distinct clones of translocation) was found among cervical carcinoma at the different stages (IB1, IIA and IIB). However, a distinct difference was found between stage IIIB and lower tumor stages, as all analyzed IIIB samples revealed a near tetraploid karyotype. Furthermore, all studied metaphases were aberrant and had a high frequency of translocations. PCC-COBRA-FISH characterization of a common type of an established culture from cervical carcinoma CSCC-1 revealed a triploidy/tetraploidy karyotype with several structural aberrations. In general, no similarity was found between this model and early stages of primary tumors. The newly established assay has a novel potential and can reveal the original status of primary tumors at different stages. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved. Show less
