Comparative proteomic expression profile in all-trans retinoic acid differentiated neuroblastoma cell line

Neuroblastoma (NB) is an infant tumor which frequently differentiates into neurons. We used twodimensional differential in-gel electrophoresis (2D-DIGE) to analyze the cytosolic and nuclear protein expression patterns of LAN-5 cells following neuronal differentiating agent all-trans-retinoic acid treatment. We identified several candidate proteins, from which Gβ2 and Prefoldin 3 may have a role on NB development. These results strength the use of proteomics to discover new putative protein targets in cancer. Keywords

Prune cAMP phosphodiesterase binds nm23-H1 and promotes cancer metastasis

We identify a new enzymatic activity underlying metastasis in breast cancer and describe its susceptibility to therapeutic inhibition. We show that human prune (h-prune), a phosphoesterase DHH family appertaining protein, has a hitherto unrecognized cyclic nucleotide phosphodiesterase activity effectively suppressed by dipyridamole, a phosphodiesterase inhibitor. h-prune physically interacts with nm23-H1, a metastasis suppressor gene. The h-prune PDE activity, suppressed by dipyridamole and enhanced by the interaction with nm23-H1, stimulates cellular motility and metastasis processes. Out of 59 metastatic breast cancer cases analyzed, 22 (37%) were found to overexpress h-prune, evidence that this novel enzymatic activity is involved in promoting cancer metastasis

MicroRNA 199b-5p delivery through stable nucleic acid lipid particles (SNALPs) in tumorigenic cell lines

MicroRNA (miR)-199b-5p has been shown to regulate Hes-1, a downstream effector of the canonical Notch and noncanonical SHH pathways, whereby it impairs medulloblastoma (MB) cancer stem cells (CSCs) through a decrease in the CD133+/CD15+ cell population. Here, we have developed stable nucleic acid lipid particles (SNALPs) that encapsulate miR-199b-5p. The efficacy of the miR- 199b-5p delivery by these SNALPs is demonstrated by significant impairment of Hes-1 levels and CSC markers in a range of different tumorigenic cell lines: colon (HT- 29, CaCo-2, and SW480), breast (MDA-MB231T and MCF-7), prostate (PC-3), glioblastoma (U-87), and MB(Daoy, ONS-76, and UW-228). After treatment with SNALP miR-199b-5p, there is also impairment of cell pro- liferation and no signs of apoptosis, as measured by cas- pases 3/7 activity and annexin V fluorescence cell sorter analyses. These data strengthen the importance of such carriers for miRNA delivery, which show no cytotoxic effects and provide optimal uptake into cells. Thus, efficient target downregulation in different tumorigenic cell lines will be the basis for future preclinical studies

MicroRNAs and Cancer Stem Cells in Medulloblastoma

In this chapter, we are describing the biology of medulloblastoma influenced by several genes/pathways which concur to its pathogenesis. Of note, several levels of regulation are mediated by miRNAs functions, which we dissect their “state of art” to underline their crucial roles on controlling cancer development. In brain tumours, literatures data, are supporting the values of Cancer Stem Cells (tumor propagating cells) and their functions for tumour recurrence for future therapeutic treatments. Thus, we link the potential use of miRNAs as “shuttle” to impair Cancer Stem Cells in medulloblastoma

Xenopus NM23-X4 regulates retinal gliogenesis through interaction with p27Xic1

Background. In Xenopus retinogenesis, p27Xic1, a Xenopus cyclin dependent kinase inhibitor, functions as a cell fate determinant in both gliogenesis and neurogenesis in a context dependent manner. This activity is essential for co-ordination of determination and cell cycle regulation. However, very little is known about the mechanism regulating the context dependent choice between gliogenesis versus neurogenesis. Results. We have identified NM23-X4, a NM23 family member, as a binding partner of p27Xic1. NM23-X4 is expressed at the periphery of the ciliary marginal zone of the Xenopus retina and the expression overlaps with p27Xic1 at the central side. Our in vivo functional analysis in Xenopus retina has shown that knockdown of NM23-X4 activates gliogenesis. Furthermore, co-overexpression of NM23-X4 with p27Xic1 results in the inhibition of p27Xic1-mediated gliogenesis, through direct interaction of NM23-X4 with the amino-terminal side of p27Xic1. This inhibitory effect on gliogenesis requires serine-150 and histidine-148, which correspond to the important residues for the kinase activities of NM23 family members. Conclusion. This study demonstrates that NM23-X4 functions as an inhibitor of p27Xic1-mediated gliogenesis in Xenopus retina and suggests that this activity contributes to the proper spatio-temporal regulation of gliogenesis

Spike S1 domain interactome in non-pulmonary systems: A role beyond the receptor recognition

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes Coronavirus Disease 2019 (COVID-19), which, since 2019 in China, has rapidly become a worldwide pandemic. The aggressiveness and global spread were enhanced by the many SARS-CoV-2 variants that have been isolated up to now. These mutations affect mostly the viral glycoprotein Spike (S), the capsid protein mainly involved in the early stages of viral entry processes, through the recognition of specific receptors on the host cell surface. In particular, the subunit S1 of the Spike glycoprotein contains the Receptor Binding Domain (RBD) and it is responsible for the interaction with the angiotensin-converting enzyme 2 (ACE2). Although ACE2 is the primary Spike host receptor currently studied, it has been demonstrated that SARS-CoV-2 is also able to infect cells expressing low levels of ACE2, indicating that the virus may have alternative receptors on the host cells. The identification of the alternative receptors can better elucidate the pathogenicity and the tropism of SARS-CoV-2. Therefore, we investigated the Spike S1 interactomes, starting from host membrane proteins of non-pulmonary cell lines, such as human kidney (HK-2), normal colon (NCM460D), and colorectal adenocarcinoma (Caco-2). We employed an affinity purification-mass spectrometry (AP-MS) to pull down, from the membrane protein extracts of all cell lines, the protein partners of the recombinant form of the Spike S1 domain. The purified interactors were identified by a shotgun proteomics approach. The lists of S1 potential interacting proteins were then clusterized according to cellular localization, biological processes, and pathways, highlighting new possible S1 intracellular functions, crucial not only for the entrance mechanisms but also for viral replication and propagation processes

Therapeutic impact of cytoreductive surgery and irradiation of posterior fossa ependymoma in the molecular era: a retrospective multicohort analysis

PURPOSE: Posterior fossa ependymoma comprises two distinct molecular variants termed EPN_PFA and EPN_PFB that have a distinct biology and natural history. The therapeutic value of cytoreductive surgery and radiation therapy for posterior fossa ependymoma after accounting for molecular subgroup is not known. METHODS: Four independent nonoverlapping retrospective cohorts of posterior fossa ependymomas (n = 820) were profiled using genome-wide methylation arrays. Risk stratification models were designed based on known clinical and newly described molecular biomarkers identified by multivariable Cox proportional hazards analyses. RESULTS: Molecular subgroup is a powerful independent predictor of outcome even when accounting for age or treatment regimen. Incompletely resected EPN_PFA ependymomas have a dismal prognosis, with a 5-year progression-free survival ranging from 26.1% to 56.8% across all four cohorts. Although first-line (adjuvant) radiation is clearly beneficial for completely resected EPN_PFA, a substantial proportion of patients with EPN_PFB can be cured with surgery alone, and patients with relapsed EPN_PFB can often be treated successfully with delayed external-beam irradiation. CONCLUSION: The most impactful biomarker for posterior fossa ependymoma is molecular subgroup affiliation, independent of other demographic or treatment variables. However, both EPN_PFA and EPN_PFB still benefit from increased extent of resection, with the survival rates being particularly poor for subtotally resected EPN_PFA, even with adjuvant radiation therapy. Patients with EPN_PFB who undergo gross total resection are at lower risk for relapse and should be considered for inclusion in a randomized clinical trial of observation alone with radiation reserved for those who experience recurrence

SARS-CoV-2 uses Spike glycoprotein to control the host's anaerobic metabolism by inhibiting LDHB

The SARS-CoV-2 pandemic, responsible for approximately 7 million deaths worldwide, highlights the urgent need to understand the molecular mechanisms of the virus in order to prevent future outbreaks. The Spike glycoprotein of SARS-CoV-2, which is critical for viral entry through its interaction with ACE2 and other host cell receptors, has been a focus of this study. The present research goes beyond receptor recognition to explore Spike's influence on cellular metabolism. AP-MS interactome analysis revealed an interaction between the Spike S1 domain and lactate dehydrogenase B (LDHB), which was further confirmed by co-immunoprecipitation and immunofluorescence, indicating colocalisation in cells expressing the S1 domain. The study showed that Spike inhibits the catalytic activity of LDHB, leading to increased lactate levels in HEK-293T cells overexpressing the S1 subunit. In the hypothesised mechanism, Spike deprives LDHB of NAD+, facilitating a metabolic switch from aerobic to anaerobic energy production during infection. The Spike-NAD+ interacting region was characterised and mainly involves the W436 within the RDB domain. This novel hypothesis suggests that the Spike protein may play a broader role in altering host cell metabolism, thereby contributing to the pathophysiology of viral infection