Σάββατο 18 Ιουνίου 2011

Μετφορμίνη και καρκίνος μαστού.


Η μετφορμίνη ( Glucophage, Glucofree, Glucoplus) είναι ένα ευρέως χρησιμοποιούμενο φάρμακο, της κατηγορίας των διγουανίδιων, για την αντιμετώπιση του σακχαρώδους διαβήτη τύπου ΙΙ. Χορηγείτε είτε ως μονοθεραπεία, είτε σε συνδυασμό με άλλα αντιδιαβητικά φάρμακα. Υπάρχουν αναφορές για ευνοϊκή επίδραση της σε υπογονιμότητα, αλλά και ενδείξεις χορήγησης της σε γυναίκες με πολυκυστικές ωοθήκες.
Μία νέα μελέτη από το Η.Β. έρχεται να προστεθεί σε προηγούμενες που έχουν δείξει μία θετική επίδραση της συγκεκριμένης ουσίας στον καρκίνο του μαστού. Σ' αυτή φάνηκε η μετφορμίνη  να ασκεί μία κατασταλτική της αύξησης των καρκινικών κυττάρων δράση, με βάση τις μετρήσεις σχετικών βιολογικών δεικτών που χρησιμοποίησαν οι ερευνητές ( Ki67 και έκφραση πολλαπλών γονιδίων).

        Breast Journal  2011 Jun 6. doi: 10.1111/j.1524-4741.2011.01089.x.
Evidence for biological effects of metformin in operable breast cancer: a pre-operative, window-of-opportunity, randomized trial.
Source
Dundee Cancer Center, University of Dundee, Ninewells Hospital and Medical School, Dundee, DD1 9SY, UK, s.hadad@nhs.net.
Abstract
Metformin may reduce the incidence of breast cancer and enhance response to neoadjuvant chemotherapy in diabetic women. This trial examined the effects of metformin on Ki67 and gene expression in primary breast cancer. Non-diabetic women with operable invasive breast cancer received pre-operative metformin. A pilot cohort of eight patients had core biopsy of the cancer at presentation, a week later (without treatment; internal control), then following metformin 500-mg o.d. for 1 week increased to 1-g b.d. for a further week continued to surgery. A further 47 patients had core biopsy at diagnosis were randomized to metformin (the same dose regimen) or no drug, and 2 weeks later had core biopsy at surgery. Ki67 immunohistochemistry, transcriptome analysis on formalin-fixed paraffin-embedded cores and serum insulin determination were performed blinded to treatment. Seven patients (7/32, 21.9%) receiving metformin withdrew because of gastrointestinal upset. The mean percentage of cells staining for Ki67 fell significantly following metformin treatment in both the pilot cohort (P = 0.041, paired t-test) and in the metformin arm (P = 0.027, Wilcoxon rank test) but was unchanged in the internal control or metformin control arms. Messenger RNA expression was significantly downregulated by metformin for PDE3B (phosphodiesterase 3B, cGMP-inhibited; a critical regulator of cAMP levels that affect activation of AMP-activated protein kinase, AMPK), confirmed by immunohistochemistry, SSR3, TP53 and CCDC14. By ingenuity pathway analysis, the tumour necrosis factor receptor 1 (TNFR1) signaling pathway was most affected by metformin: TGFB and MEKK were upregulated and cdc42 downregulated; mTOR and AMPK pathways were also affected. Gene set analysis additionally revealed that p53, BRCA1 and cell cycle pathways also had reduced expression following metformin. Mean serum insulin remained stable in patients receiving metformin but rose in control patients. This trial presents biomarker evidence for anti-proliferative effects of metformin in women with breast cancer and provides support for therapeutic trials of metformin

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