There is growing epidemiological evidence indicating an association between diabetes mellitus and the increased incidence of colorectal cancer (CRC). The preferred initial and most widely used pharmacological agent for the treatment of type 2 diabetes is metformin, which in parallel reduces the risk of CRC and improves patient prognosis. AMP-activated protein kinase (AMPK) appears to be tightly associated with the beneficial metabolic effects of metformin, serving as a cellular energy sensor activated in response to a variety of conditions that deplete cellular energy levels. Such conditions include nutrient starvation (particularly glucose), hypoxia and exposure to toxins that inhibit the mitochondrial respiratory chain complex. The aim of the present study was to determine the effect of metformin on CRC cell lines, with different levels of anterior gradient 2 (AGR2) expression, exposed to 5-fluorouracil (5-FU) and oxaliplatin, alone or in combination with metformin. AGR2 has recently emerged as a factor involved in colon carcinogenesis. In AGR2-knockout cells, markedly higher levels of phosphorylated-AMPK were observed in comparison with control cells transfected with GFP-scrambled guide RNA, which indicated that the presence of AGR2 may interfere with the metformin-dependent activation of AMPK. In addition, metformin in combination with 5-FU and oxaliplatin induced ROS production and attenuated autophagy. This effect was enhanced in AGR2-knockout cells.

• Klíčová slova
• AGR2, AMPK, ROS, autophagy, colorectal cancer, diabetes mellitus,
• Publikační typ
• časopisecké články MeSH

BACKGROUND: During cancer progression, epithelial cancer cells can be reprogrammed into mesenchymal-like cells with increased migratory potential through the process of epithelial-mesenchymal transition (EMT), representing an essential step of tumor progression towards metastatic state. AGR2 protein was shown to regulate several cancer-associated processes including cellular proliferation, survival and drug resistance. METHODS: The expression of AGR2 was analyzed in cancer cell lines exposed to TGF-β alone or to combined treatment with TGF-β and the Erk1/2 inhibitor PD98059 or the TGF-β receptor specific inhibitor SB431542. The impact of AGR2 silencing by specific siRNAs or CRISPR/Cas9 technology on EMT was investigated by western blot analysis, quantitative PCR, immunofluorescence analysis, real-time invasion assay and adhesion assay. RESULTS: Induction of EMT was associated with decreased AGR2 along with changes in cellular morphology, actin reorganization, inhibition of E-cadherin and induction of the mesenchymal markers vimentin and N-cadherin in various cancer cell lines. Conversely, induction of AGR2 caused reversion of the mesenchymal phenotype back to the epithelial phenotype and re-acquisition of epithelial markers. Activated Smad and Erk signaling cascades were identified as mutually complementary pathways responsible for TGF-β-mediated inhibition of AGR2. CONCLUSION: Taken together our results highlight a crucial role for AGR2 in maintaining the epithelial phenotype by preventing the activation of key factors involved in the process of EMT.

• Klíčová slova
• AGR2, E-cadherin, EMT, Metastasis, TGF-β, Vimentin,
• MeSH
• buněčná adheze genetika   MeSH
• epitelo-mezenchymální tranzice účinky léků   genetika   MeSH
• genový knockdown MeSH
• kadheriny metabolismus   MeSH
• lidé MeSH
• mukoproteiny MeSH
• nádorové buněčné linie MeSH
• onkogenní proteiny MeSH
• pohyb buněk genetika   MeSH
• proteiny Smad metabolismus   MeSH
• proteiny genetika   MeSH
• regulace genové exprese u nádorů účinky léků   MeSH
• signální transdukce účinky léků   MeSH
• transformující růstový faktor beta farmakologie   MeSH
• vimentin metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• AGR2 protein, human MeSH Prohlížeč
• kadheriny MeSH
• mukoproteiny MeSH
• onkogenní proteiny MeSH
• proteiny Smad MeSH
• proteiny MeSH
• transformující růstový faktor beta MeSH
• vimentin MeSH

Anterior gradient protein (AGR) 3 is a highly related homologue of pro-oncogenic AGR2 and belongs to the family of protein disulfide isomerases. Although AGR3 was found in breast, ovary, prostate, and liver cancer, it remains of yet poorly defined function in tumorigenesis. This study aimed to determine AGR3 expression in a cohort of 129 primary breast carcinomas and evaluate the clinical and prognostic significance of AGR3 in these tumors. The immunohistochemical analysis revealed the presence of AGR3 staining to varying degrees in 80% of analyzed specimens. The percentage of AGR3-positive cells significantly correlated with estrogen receptor, progesterone receptor (both P<0.0001) as well as low histological grade (P=0.003), and inversely correlated with the level of Ki-67 expression (P<0.0001). In the whole cohort, AGR3 expression was associated with longer progression-free survival (PFS), whereas AGR3-positive subgroup of low-histological grade tumors showed both significantly longer PFS and overall survival. In conclusion, AGR3 is associated with the level of differentiation, slowly proliferating tumors, and more favorable prognosis of breast cancer patients.

• Klíčová slova
• AGR3, ER-positive breast cancer, immuno histochemistry, patient survival, protein disulfide isomerase,
• Publikační typ
• časopisecké články MeSH

Endocrine resistance is a significant problem in breast cancer treatment. Thus identification and validation of novel resistance determinants is important to improve treatment efficacy and patient outcome. In our work, AGR2 expression was determined by qRT-PCR in Tru-Cut needle biopsies from tamoxifen-treated postmenopausal breast cancer patients. Our results showed inversed association of AGR2 mRNA levels with primary treatment response (P = 0.0011) and progression-free survival (P = 0.0366) in 61 ER-positive breast carcinomas. As shown by our experimental and clinical evaluations, elevated AGR2 expression predicts decreased efficacy of tamoxifen treatment. From this perspective, AGR2 is a potential predictive biomarker enabling selection of an optimal algorithm for adjuvant hormonal therapy in postmenopausal ER-positive breast cancer patients.

• MeSH
• chemorezistence genetika   MeSH
• hormonální protinádorové látky terapeutické užití   MeSH
• karcinom diagnóza   farmakoterapie   genetika   metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• messenger RNA genetika   metabolismus   MeSH
• mukoproteiny MeSH
• nádorové biomarkery genetika   metabolismus   MeSH
• nádory prsu diagnóza   farmakoterapie   genetika   metabolismus   MeSH
• onkogenní proteiny MeSH
• postmenopauza metabolismus   MeSH
• proteiny genetika   metabolismus   MeSH
• regulace genové exprese u nádorů MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• studie případů a kontrol MeSH
• tamoxifen terapeutické užití   MeSH
• výsledek terapie MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• AGR2 protein, human MeSH Prohlížeč
• hormonální protinádorové látky MeSH
• messenger RNA MeSH
• mukoproteiny MeSH
• nádorové biomarkery MeSH
• onkogenní proteiny MeSH
• proteiny MeSH
• tamoxifen MeSH