Analiza ekspresije kljuĉnih molekula PTEN/PI3K/mTOR signalnog puta i ABC transportera kod trostruko negativnih karcinoma dojke i njihova povezanost sa histopatološkim i kliniĉkim parametrima
Expression analysis of key molecules of PTEN/PI3K/mTOR signalling pathway and ABC transporters in triple negative breast cancer and their associaton with histopathological and clinical parameters
Докторанд
Prvanović, MirjanaМентор
Tanić, NikolaЧланови комисије
Savić-Pavićević, DušankaBrajušković, Goran
Milovanović, Zorka
Tatić, Svetislav
Метаподаци
Приказ свих података о дисертацијиСажетак
Trostruko negativni karcinomi dojke su klinički i genetički visoko heterogena grupa humanih
maligniteta a zbog varijabilnog odgovora na terapiju predstavljaju jedan od glavnih izazova za
savremeno društvo, istraţivače i kliničare. TNBC ne eksprimiraju molekularne markere, estrogenski
receptor-ER, progesteronski receptor-PR i receptor za humani epidermalni faktor rasta 2-HER2.
Navedeni molekularni markeri su ključni za izbor prave terapije i u direktnoj su vezi sa kliničkim
ponašanjem, rezistencijom na hemioterapeutike i ishodom bolesti.
PTEN/PI3K/AkT/mTOR (PAM) signalni put i prekomerna ekspresija ABC transportera mogu biti
odgovorni za rezistenciju na hemoterapeutike. U vezi sa tim, cilj ove studije bio je utvrđivanje
bioloških mehanizama koji su u osnovi rezistencije na hemioterapiju.
PAM signalni put je značajan za progresiju humanih tumora a abnormalna aktivacija PAM
signalnog puta jedan je od najčešće poremećenih signalnih puteva u karcinomima dojke. Zato je
jedan od osnovnih cilj...eva ove studije bio ispitivanje imunoekspresionog profila PTEN, PI3K i
mTOR protein i ABCB1 (MDR1) membranskog transportera i njihova povezanost i sa kliničkim i
histopatološkim parametrima, tokom i ishodom bolesti.
U cilju utvrđivanja molekularnih mehanizama odgovornih za redukciju ili potpuni gubitak
ekspresije PTEN proteina, urađena je analiza gubitka heterozigotnosti (LOH), RT-qPCR metodom,
kao pretpostavljenog najčešćeg mehanizma inaktivacije PTEN tumor supresor gena. Ekspresioni
profili PTEN, PI3K, mTORproteina i MDR1 transportera dobijeni su imunohistohemijskom (IHC)
analizom.
Pokazali smo da je suprimirana ili odsutna PTEN ekspresija sa visokom ekspresijom PI3K i mTOR
proteina u asocijaciji sa lošim ishodom bolesti. Potvrdili smo da su PTEN delecije glavni
mehanizam i uzrok smanjene ili odsutne ekspesije PTEN proteina. Takođe, pokazali smo da se
agresivno ponašanje i češće javljanje metastaza TNBC tumora mogu pripisati značajno češćem
gubitku heterozigotnosti (LOH) PTEN tumor supresor gena. Homozigotne delecije (ne i
hemizigotne) bi mogle biti potencijalni marker metastatske bolesti i dobar indikator (pokazatelj)
prognoze TNBC tumora...
Triple negative breast cancers are a clinically and genetically highly heterogenous group of human
tumours and, due to their variable response to therapy, represent one of the main challenges for
modern society, researchers and clinicians. TNBCs do not express molecular markers, estrogen-ER,
progesterone-PR, and human growth epidermal factor 2-HER2. These molecular markers are
crucial for choosing the right therapy and are directly related to clinical behiavior, resistence to
chemotherapeutics and disease outcome. The PTEN/PI3K/Akt/mTOR (PAM) signaling pathway
and overexpression of the ABCB1 transporter may be responsible for resistance to
chemiotherapeutics. In this regard, the aim of this study was to determine the biological
mechanisams underlying chemotherapy resistance. The PAM signaling pathway is one of the most
commonly disrupted signaling pathways in breast cancers. Therefore, one of the main objectives of
this study was to examine the immunoexpression profile of PTEN, PI3K an...d mTOR proteins and
expression profile of ABCB1 (MDR1) membrane transporter and their association with clinical and
histopathological parameters, course of disease and disease outcome. In order to determine the
molecular mechanisams responsible for the reduction or complete loss of the PTEN gene allele, we
performed LOH analysis as the presumed most common mechanism of PTEN tumour suppressor
gene inactivation. Loss of heterozigosity (LOH) of the PTEN tumour suppressor gene was
preformed by RT-qPCR method and the expression profile of PTEN, PI3K, mTOR proteins and
MDR1 transporter by IHC analysis. . Suppresed or absent PTEN expression with high expression
of PI3K and mTOR proteins was found to be associated with poor disease outcome. PTEN deletions
are a mayor cause of reduced or absent PTEN protein expression. It has been esthablished that
MDR1 could be responsible for multidrug resistance to TNBC tumour chemotherapy due to a more
frequent and high expression score. It was found that aggressive behavior and more frequent
occurrence of the TNBC tumor metastases can be attributed to significally more frequent loss of
heterozigosity (LOH) of the PTEN tumour suppressor gene. Homozygous (but not hemyzigotic)
could be a potential marker of metastasis formation and a good predictor (indicator) of TNBC
outcome. These data could contribute to the development of personalized medicine and the
establishment of new therapeutic approaches. In other words, a logical strategy in the therapeutic
approach, could be simultaneously targeting molecular markers of PTEN/PI3K/mTOR signaling
pathway with MDR1 membrane pump in treatment of TNBC patients.