Breast cancer and microRNAs: therapeutic impact

Summary Despite advances in detection and therapies, breast cancer is still the leading cause of cancer death in women worldwide. The etiology of this neoplasm is complex, and both genetic and environmental factors contribute to the complicate scenario. Gene profiling studies have been extensively used over the last decades as a powerful tool to define the signature of different cancers and to predict outcome and response to therapies. More recently, a new class of small (19-25 nucleotides) non-coding RNAs, microRNAs (miRs or miRNAs) has been linked to several human diseases, included cancer. MicroRNAs are involved in temporal and tissue-specific eukaryotic gene regulation, 1 either by translational inhibition or exonucleolytic mRNA decay, targeted through imperfect complementarity between the microRNA and the 3′ untranslated region (3′UTR) of the mRNA. 2 Since their ability to potentially target any human mRNA, it is likely that microRNAs are involved in almost every biological process, including cell cycle regulation, cell growth, apoptosis, cell differentiation and stress response. 3 The involvement of microRNAs in the biology of human cancer is supported by an increasing body of experimental evidence, that has gradually switched from profiling studies, as the first breast cancer specific signature reported in 2005 by our group 4 describing an aberrant microRNA expression in different tumor types, to biological demonstrations of the causal role of these small molecules in the tumorigenic process, and the possible implications as biomarkers or therapeutic tools. 5 These more recent studies have widely demonstrated that microRNAs can modulate oncogenic or tumor suppressor pathways, and that, at the same time, their expression can be regulated by oncogenes or tumor suppressor genes. The possibility to modulate microRNA expression both in vitro and in vivo by developing synthetic pre-microRNA molecules or antisense oligonucletides has at the same time provided a powerful tool to a deeper comprehension of the molecular mechanisms regulated by these molecules, and suggested the intriguing and promising perspective of a possible use in therapy. Here we review our current knowledge about the involvement of microRNAs in cancer, focusing particularly on breast cancer, and their potential as diagnostic, prognostic and therapeutic tools

Regulation of a progenitor gene program by SOX4 is essential for mammary tumor proliferation

In breast cancer the transcription factor SOX4 has been shown to be associated with poor survival, increased tumor size and metastasis formation. This has mostly been attributed to the ability of SOX4 to regulate Epithelial-to-Mesenchymal-Transition (EMT). However, SOX4 regulates target gene transcription in a context-dependent manner that is determined by the cellular and epigenetic state. In this study we have investigated the loss of SOX4 in mammary tumor development utilizing organoids derived from a PyMT genetic mouse model of breast cancer. Using CRISPR/Cas9 to abrogate SOX4 expression, we found that SOX4 is required for inhibiting differentiation by regulating a subset of genes that are highly activated in fetal mammary stem cells (fMaSC). In this way, SOX4 re-activates an oncogenic transcriptional program that is regulated in many progenitor cell-types during embryonic development. SOX4-knockout organoids are characterized by the presence of more differentiated cells that exhibit luminal or basal gene expression patterns, but lower expression of cell cycle genes. In agreement, primary tumor growth and metastatic outgrowth in the lungs are impaired in SOX4KO tumors. Finally, SOX4KO tumors show a severe loss in competitive capacity to grow out compared to SOX4-proficient cells in primary tumors. Our study identifies a novel role for SOX4 in maintaining mammary tumors in an undifferentiated and proliferative state. Therapeutic manipulation of SOX4 function could provide a novel strategy for cancer differentiation therapy, which would promote differentiation and inhibit cycling of tumor cells

Monte-Carlo Simulation of Decananometric nMOSFETs: Multi-Subband vs. 3D-Electron Gas with Quantum Corrections

7In this paper two Monte-Carlo simulators implementing different models for the influence of carrier quantization on the electrostatics and transport are used to analyze sub-100 nm double-gate SOI devices. To this purpose a new stable and efficient scheme to implement the contacts in the simulation of double-gate SOI devices is introduced first. Then, results in terms of drain current and microscopic quantities are compared, providing new insight on the limitation of a well assessed semiclassical transport simulation approach and a more rigorous multi-subband model.reservedmixedI.RIOLINO; M.BRACCIOLI; L.LUCCI; P.PALESTRI; ESSENI D; C.FIEGNA; L.SELMII., Riolino; M., Braccioli; Lucci, Luca; Palestri, Pierpaolo; Esseni, David; C., Fiegna; Selmi, Luc

Delayed administration of neural stem cells after hypoxia-ischemia reduces sensorimotor deficits, cerebral lesion size, and neuroinflammation in neonatal mice

Background Hypoxic-ischemic (HI) encephalopathy causes mortality and severe morbidity in neonates. Treatments with a therapeutic window >6 hours are currently not available. Here we explored whether delayed transplantation of allogenic neural stem cells (NSCs) at 10 days after HI could be a tool to repair HI brain injury and improve behavioral impairments. Methods HI was induced in 9 day-old mice. Animals received NSCs or vehicle intracranially in the hippocampus at 10 days post-HI. Sensorimotor performance was assessed by cylinder rearing test. Lesion size, synaptic integrity and fate of injected NSCs were determined by immuno-stainings. Neuroinflammation was studied by immuno-stainings of brain sections, primary glial cultures and TNFα ELISA. Results NSC transplantation at 10 days post-insult induced long-term improvement of motor performance and synaptic integrity, and reduced lesion size compared to vehicle-treatment. HI-induced neuroinflammation was reduced after NSC treatment, at least partially by factors secreted by NSCs. Injected NSCs migrated towards and localized at the damaged hippocampus. Transplanted NSCs differentiated towards the neuronal lineage and formed a niche with endogenous precursors. Conclusion Our study provides evidence of the efficacy of NSC transplantation late after HI as a tool to reduce neonatal HI brain injury through regeneration of the lesion

Delayed administration of neural stem cells after hypoxia-ischemia reduces sensorimotor deficits, cerebral lesion size, and neuroinflammation in neonatal mice

Background Hypoxic-ischemic (HI) encephalopathy causes mortality and severe morbidity in neonates. Treatments with a therapeutic window >6 hours are currently not available. Here we explored whether delayed transplantation of allogenic neural stem cells (NSCs) at 10 days after HI could be a tool to repair HI brain injury and improve behavioral impairments. Methods HI was induced in 9 day-old mice. Animals received NSCs or vehicle intracranially in the hippocampus at 10 days post-HI. Sensorimotor performance was assessed by cylinder rearing test. Lesion size, synaptic integrity and fate of injected NSCs were determined by immuno-stainings. Neuroinflammation was studied by immuno-stainings of brain sections, primary glial cultures and TNFα ELISA. Results NSC transplantation at 10 days post-insult induced long-term improvement of motor performance and synaptic integrity, and reduced lesion size compared to vehicle-treatment. HI-induced neuroinflammation was reduced after NSC treatment, at least partially by factors secreted by NSCs. Injected NSCs migrated towards and localized at the damaged hippocampus. Transplanted NSCs differentiated towards the neuronal lineage and formed a niche with endogenous precursors. Conclusion Our study provides evidence of the efficacy of NSC transplantation late after HI as a tool to reduce neonatal HI brain injury through regeneration of the lesion

SOX4 inhibits oligodendrocyte differentiation of embryonic neural stem cells in vitro by inducing Hes5 expression

SOX4 has been shown to promote neuronal differentiation both in the adult and embryonic neural progenitors. Ectopic SOX4 expression has also been shown to inhibit oligodendrocyte differentiation in mice, however the underlying molecular mechanisms remain poorly understood. Here we demonstrate that SOX4 regulates transcriptional targets associated with neural development in neural stem cells (NSCs), reducing the expression of genes promoting oligodendrocyte differentiation. Interestingly, we observe that SOX4 levels decreased during oligodendrocyte differentiation in vitro. Moreover, we show that SOX4 knockdown induces increased oligodendrocyte differentiation, as the percentage of Olig2-positive/2′,3’-Cyclic-nucleotide 3′-phosphodiesterase (CNPase)-positive maturing oligodendrocytes increases, while the number of Olig2-positive oligodendrocyte precursors is unaffected. Conversely, conditional SOX4 overexpression utilizing a doxycycline inducible system decreases the percentage of maturing oligodendrocytes, suggesting that SOX4 inhibits maturation from precursor to mature oligodendrocyte. We identify the transcription factor Hes5 as a direct SOX4 target gene and we show that conditional overexpression of Hes5 rescues the increased oligodendrocyte differentiation mediated by SOX4 depletion in NSCs. Taken together, these observations support a novel role for SOX4 in NSC by controlling oligodendrocyte differentiation through induction of Hes5 expression

SOX4 inhibits oligodendrocyte differentiation of embryonic neural stem cells in vitro by inducing Hes5 expression

SOX4 has been shown to promote neuronal differentiation both in the adult and embryonic neural progenitors. Ectopic SOX4 expression has also been shown to inhibit oligodendrocyte differentiation in mice, however the underlying molecular mechanisms remain poorly understood. Here we demonstrate that SOX4 regulates transcriptional targets associated with neural development in neural stem cells (NSCs), reducing the expression of genes promoting oligodendrocyte differentiation. Interestingly, we observe that SOX4 levels decreased during oligodendrocyte differentiation in vitro. Moreover, we show that SOX4 knockdown induces increased oligodendrocyte differentiation, as the percentage of Olig2-positive/2′,3’-Cyclic-nucleotide 3′-phosphodiesterase (CNPase)-positive maturing oligodendrocytes increases, while the number of Olig2-positive oligodendrocyte precursors is unaffected. Conversely, conditional SOX4 overexpression utilizing a doxycycline inducible system decreases the percentage of maturing oligodendrocytes, suggesting that SOX4 inhibits maturation from precursor to mature oligodendrocyte. We identify the transcription factor Hes5 as a direct SOX4 target gene and we show that conditional overexpression of Hes5 rescues the increased oligodendrocyte differentiation mediated by SOX4 depletion in NSCs. Taken together, these observations support a novel role for SOX4 in NSC by controlling oligodendrocyte differentiation through induction of Hes5 expression