Role of TGFβ family members on physiological angiogenesis and ovarian cancer

[eng] Role of TGF? in physiological angiogenesis and ovarian cancer Transforming Growth Factor Beta (TGF?) is a signalling pathway involved in a wide range of cellular processes such as proliferation, differentiation, angiogenesis, migration and homeostasis. In addition, it has been broadly related with pathological situations like cancer or other diseases. In this thesis we have been focused on two of its receptors; the T?RI called ALK5, ubiquitously expressed, and ALK1, an endothelial cell-restricted receptor. In the first part of this work we have studied the role of ALK1 in angiogenesis. Loss of function mutations in ALK1 cause a subtype of hereditary haemorrhagic telangiectasias (HHTs) characterized by vasculature malformations. Currently, there is no suitable treatment to cure these patients. To study the ALK1 role in vascular development, we have used the retina mouse model and seeking to find a treatment for these patients, we have used a mouse model for HHTs. This mouse model has a heterozygous alteration in ALK1, as in homozygosis die at +/- mice resulted in abnormal endothelial cell proliferation mid-gestion. The alteration on ALK1 and increased retinal vessel width without affecting pericyte coverage, migration or elongation of the ECs. We have shown that genetic and pharmacological inhibition of PI3K signalling +/- abolished the increase in vessel width in ALK1 retinas and normalized vasculature. Overall, our results suggest the potential for using PI3K inhibitors as new therapeutic agents for treating HHTs. In the second part of this work we have searched for new therapeutic targets for treating epithelial ovarian cancer. Firstly, we analysed the TGF? signalling pathway in these tumours. Using a Tissue Micro Array (TMA) with patient samples we found high Smad2 phosphorylation, a read-out of ALK5 activation, in epithelial ovarian cancer tumoral cells, independently of tumour subtype (high-grade serous or endometrioid). To evaluate the impact of TGF? receptor inhibition on tumoral growth, we used different models of human epithelial ovarian cancer orthotopically grown in nude mice (OVAs); two high-grade serous carcinoma and one endometrioid carcinoma. We have confirmed that the histological properties and the levels of phosphoSmad2 expression pattern were maintained on the ovarian tumour mouse models compared to its human primary tumours samples. Treatment with a TGF?RII increasing IGF1R internalization and degradation through the lysosome. When IGF1R levels were decreased by shRNA treatment, ovarian cancer cell lines grew less and LY2109761 lost its capacity to block tumoral ovarian cell proliferation. Overall, our results suggest an important role for the TGF? signalling pathway in ovarian tumour cell growth through the control of IGF1R signalling pathway. Moreover, it identifies anti-TGF? inhibitors as being of potential use in new therapies for ovarian cancer patients as an alternative to IGF1R inhibition, being used in clinical trials. [cat] Aquest treball estudia el paper de la familia del Factor de Creixement Transformant (TGF?) en el cancer d’ovari i en una altra patologia, la telangectasia hemorragica hereditaria (HHT). Mutacions de perdua de funcio del receptor ALK1 causen un subtipus de HHT caracteritzat per malformacions vasculars. Per analitzar el rol d'ALK1 en el desenvolupament vascular, hem utilitzat un model animal d'HHT. Les alteracions obtingudes han estat una proliferacio anormal de les cel.lules endotelials i un augment de l'amplitud dels vasos de la retina dels ratolins ALK1+/-. Hem demostrat que una inhibicio genetica o farmacologica de la via de senyalitzacio de PI3K aboleix l'augment de l'amplitud de vasos i la vasculatura queda normalitzada, suggerint el potencial us dels inhibidors de PI3K com a nous agents terapeutics pel tractament d'aquests pacients. En la segona part d'aquest treball, hem buscat nous agents terapeutics pel tractament del cancer d'ovari. Utilitzant mostres de pacients, hem observat alts nivells de Smad2 fosforilat en les cel.lules tumorals de cancer d'ovari, independentment del tipus de tumor. El tractament amb l'inhibidor de TGF?RI&II, LY2109761, en els models ortotopics de cancer d'ovari causa una reduccio significativa de la mida tumoral, afectant la proliferacio cellular. Hem identificat el receptor del Factor de Creixement de la Insulina (IGF)1 com la via implicada en la proliferacio de les cel.lules tumorals d'ovari, la qual es regulada positivament per TGF?. La inhibicio de l'activitat d'IGF1R inhibeix el creixement del tumor d'ovari in vivo. A nivell molecular, TGF? controla els nivells de mRNA d'IGF1R i tambe la seva internalitzacio i degradacio proteica a traves del lisosoma. Quan els nivells d'IGF1R son disminuits per la utilitzacio d'un shRNA, LY2109761 perd la capacitat de bloquejar la proliferacio de la cel.lula tumoral d'ovari. Aquests resultats postulen que TGF?. te un paper important en el creixement cellular del tumor d'ovari a traves del control de la senyalitzacio d'IGF1R. A mes, identifica els inhibidors contra TGF? com a noves terapies pels pacients de cancer d'ovari com una alternativa als inhibidors d'IGF1R.