Targeting the Hedgehog Pathway in Rhabdomyosarcoma

Embryonic pathways; Paediatric cancer; Soft tissue sarcomasVies embrionàries; Càncer pediàtric; Sarcomes de teixits tousVías embrionarias; Cáncer pediátrico; Sarcomas de tejidos blandosAberrant activation of the Hedgehog (Hh) signalling pathway is known to play an oncogenic role in a wide range of cancers; in the particular case of rhabdomyosarcoma, this pathway has been demonstrated to be an important player for both oncogenesis and cancer progression. In this review, after a brief description of the pathway and the characteristics of its molecular components, we describe, in detail, the main activation mechanisms that have been found in cancer, including ligand-dependent, ligand-independent and non-canonical activation. In this context, the most studied inhibitors, i.e., SMO inhibitors, have shown encouraging results for the treatment of basal cell carcinoma and medulloblastoma, both tumour types often associated with mutations that lead to the activation of the pathway. Conversely, SMO inhibitors have not fulfilled expectations in tumours—among them sarcomas—mostly associated with ligand-dependent Hh pathway activation. Despite the controversy existing regarding the results obtained with SMO inhibitors in these types of tumours, several compounds have been (or are currently being) evaluated in sarcoma patients. Finally, we discuss some of the reasons that could explain why, in some cases, encouraging preclinical data turned into disappointing results in the clinical setting.This article was funded by grants from: Institut Català d’Oncologia (ICO); Instituto de Salud Carlos III (PI18/00398 and FI18/00178); ACCIÓ (COMRDI15-1-0014); Fundació la Marató de TV3; Fundació Albert Bosch; Rotary Clubs Barcelona Eixample, Barcelona Diagonal, Santa Coloma de Gramanet, München-Blutenburg, Deutschland Gemeindienst e.V. and others from Barcelona and province; Fundation Amics Joan Petit; Del Hospital a la cathedral Initiative by Xavi Vallès; and Mi compañero de viaje Association

Integrin alpha9 emerges as a key therapeutic target to reduce metastasis in rhabdomyosarcoma and neuroblastoma

Dissemination; Paediatric cancer; Solid tumoursDiseminación; Cáncer pediátrico; Tumores sólidosDisseminació; Càncer pediàtric; Tumors sòlidsThe majority of current cancer therapies are aimed at reducing tumour growth, but there is lack of viable pharmacological options to reduce the formation of metastasis. This is a paradox, since more than 90% of cancer deaths are attributable to metastatic progression. Integrin alpha9 (ITGA9) has been previously described as playing an essential role in metastasis; however, little is known about the mechanism that links this protein to this process, being one of the less studied integrins. We have now deciphered the importance of ITGA9 in metastasis and provide evidence demonstrating its essentiality for metastatic dissemination in rhabdomyosarcoma and neuroblastoma. However, the most translational advance of this study is to reveal, for the first time, the possibility of reducing metastasis by pharmacological inhibition of ITGA9 with a synthetic peptide simulating a key interaction domain of ADAM proteins, in experimental metastasis models, not only in childhood cancers but also in a breast cancer model.This research was supported by grants from: Institut Català d’Oncologia (ICO); Instituto de Salud Carlos III (PI18/00398 and FI18/00178); ACCIÓ (COMRDI15-1-0014); Fundació la Marató de TV3; Fundació A. BOSCH; Rotary Clubs Barcelona Eixample, Barcelona Diagonal, Santa Coloma de Gramanet, München-Blutenburg, Deutschland Gemeindienst e.V. and others from Barcelona and province; Eric Abidal Foundation; Del Hospital a la catedral Initiative by Xavi Vallès; and Mi compañero de viaje Association