Hepatocellular carcinoma (HCC) is a serious public health problem, without an effective cure. It has been demonstrated that the deregulation of microRNAs expression contribute to tumorigenesis. In HCC, miR-221 was shown to be up-regulated in more than 70% of the cases and was associated with higher tumor stage, metastasis and a shorter time to recurrence after surgery. A tumor promoting function of miR-221 was proved in a transgenic mouse model, which was predisposed to the development of liver cancers. These findings suggested that miR-221 could represent a potential target for anti-tumor approaches. Conversely, miR-199a is of interest because its level was shown to be reduced in almost 100% of HCC, it was significantly correlated with poor prognosis and was shown to target c-Met, an oncogene involved in invasion and metastasis. In the present thesis, novel Adenoviruses and Adeno-Associated viral vector (AAVVs) were developed. They were genetically modified to drive the expression of multiple binding sites for miR-221, the “miR-221 sponge”, as well as miRNA precursor for miR-199a. Analysis of miR-221 sponge in HCC cells revealed the capability to reduce miR-221 endogenous levels, which was accompanied by an increase in CDKN1B/p27 protein, a known target of miR-221. An increase in apoptosis was detected in Hep3B cells after infection with any of adeno or AAVs in comparison with control viruses. Moreover, restoring the level of miR-199a could also reduce viability and increase apoptosis of HepG2 cells. Therapeutic efficacy of miR-221 antisense oligonucleotides and a tumor suppressive role of miR-199a alone or in combination with sorafenib were also evaluated. We showed that combining an antimiR-221/mimic miR-199a with sorafenib improves the response of HCC cells to molecular targeted treatment through enhancing the inhibition of cell proliferation and induction of apoptosis and arresting the cell cycle in G1. To validate the therapeutic potential of miR-199a, we demonstrated that in vivo delivery of miR-199a oligonucleotide leads to a reduction of the number and size of tumor nodules as sorafenib, without any apparent toxicity. This study showed that methods for modulating microRNA activities could elicit measurable anti-tumor effects, that deserve further study to improve existing therapies.

MicroRNA-Based Therapeutics in Hepatocellular Carcinoma: In Vitro and in Vivo Studies

MOSHIRI, Farzaneh
2015

Abstract

Hepatocellular carcinoma (HCC) is a serious public health problem, without an effective cure. It has been demonstrated that the deregulation of microRNAs expression contribute to tumorigenesis. In HCC, miR-221 was shown to be up-regulated in more than 70% of the cases and was associated with higher tumor stage, metastasis and a shorter time to recurrence after surgery. A tumor promoting function of miR-221 was proved in a transgenic mouse model, which was predisposed to the development of liver cancers. These findings suggested that miR-221 could represent a potential target for anti-tumor approaches. Conversely, miR-199a is of interest because its level was shown to be reduced in almost 100% of HCC, it was significantly correlated with poor prognosis and was shown to target c-Met, an oncogene involved in invasion and metastasis. In the present thesis, novel Adenoviruses and Adeno-Associated viral vector (AAVVs) were developed. They were genetically modified to drive the expression of multiple binding sites for miR-221, the “miR-221 sponge”, as well as miRNA precursor for miR-199a. Analysis of miR-221 sponge in HCC cells revealed the capability to reduce miR-221 endogenous levels, which was accompanied by an increase in CDKN1B/p27 protein, a known target of miR-221. An increase in apoptosis was detected in Hep3B cells after infection with any of adeno or AAVs in comparison with control viruses. Moreover, restoring the level of miR-199a could also reduce viability and increase apoptosis of HepG2 cells. Therapeutic efficacy of miR-221 antisense oligonucleotides and a tumor suppressive role of miR-199a alone or in combination with sorafenib were also evaluated. We showed that combining an antimiR-221/mimic miR-199a with sorafenib improves the response of HCC cells to molecular targeted treatment through enhancing the inhibition of cell proliferation and induction of apoptosis and arresting the cell cycle in G1. To validate the therapeutic potential of miR-199a, we demonstrated that in vivo delivery of miR-199a oligonucleotide leads to a reduction of the number and size of tumor nodules as sorafenib, without any apparent toxicity. This study showed that methods for modulating microRNA activities could elicit measurable anti-tumor effects, that deserve further study to improve existing therapies.
NEGRINI, Massimo
CUNEO, Antonio
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/2389095
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