Structural deciphering of the NG2/CSPG4 proteoglycan multifunctionality.

The chondroitin sulfate proteoglycan 4 ( CSPG4) gene encodes a transmembrane proteoglycan (PG) constituting the largest and most structurally complex macromolecule of the human surfaceome. Its transcript shows an extensive evolutionary conservation and, due to the elaborated intracellular processing of the translated protein, it generates an array of glycoforms with the potential to exert variant-specific functions. CSPG4-mediated molecular events are articulated through the interaction with more than 40 putative ligands and the concurrent involvement of the ectodomain and cytoplasmic tail. Alternating inside-out and outside-in signal transductions may thereby be elicited through a tight functional connection of the PG with the cytoskeleton and its regulators. The potential of CSPG4 to influence both types of signaling mechanisms is also asserted by its lateral mobility along the plasma membrane and its intersection with microdomain-restricted internalization and endocytic trafficking. Owing to the multitude of molecular interplays that CSPG4 may engage, and thanks to a differential phosphorylation of its intracellular domain accounted by crosstalking signaling pathways, the PG stands out for its unique capability to affect numerous cellular phenomena, including those purporting pathologic conditions. We discuss here the progresses made in advancing our understanding about the structural-functional bases for the ability of CSPG4 to widely impact on cell behavior, such as to highlight how its multivalency may be exploited to interfere with disease progression.-Tamburini, E., Dallatomasina, A., Quartararo, J., Cortelazzi, B., Mangieri, D., Lazzaretti, M., Perris, R. Structural deciphering of the NG2/CSPG4 proteoglycan multifunctionality.

Virological surveillance of SARS-CoV-2 in an Italian Northern area: differences in gender, age and Real Time RT PCR cycle threshold (Ct) values in three epidemic periods.

BACKGROUND AND AIM OF THE WORK: Coronavirus Disease 2019 (COVID-19), caused by the novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), is a global public health emergency. The aim of this study was to investigate cases characteristics and Real Time RT PCR cycle threshold (Ct) values distribution of COVID-19 in an Italian Northern area during three periods: first period, February-May 2020; second period, June-August 2020; third period, September 2020-February 2021. METHODS: Real Time RT PCR was used to detect SARS-CoV-2 in respiratory samples (oro/nasopharyngeal swabs). RESULTS: A total of 254,744 samples were tested during the study period. Out of 20,188 positive samples (7.92%), 10,303 were females (51.04%) and 9,885 were males (48.96%). The percentage of positivity varied during the three different periods: 14.1% in the first period, 1.4% in the second and 9.2% in the third. The lowest Ct values were observed in the first phase of pandemic, with an overall average of 25.64. Overall average of the Ct values was lower in males than in females, 26.29 ± 6.04 and 26.84 ± 5.99 respectively. The oldest patients recorded lower Ct values. CONCLUSIONS: The findings of our study represent further evidence in support of the fact that male sex and older age showed lower Ct values, which means higher viral loads and higher infectious potential. These knowledges are useful to better understand the epidemiological aspects of COVID-19 and to perform effective Public Health Policies.

Adenomatous polyposis coli alteration in digestive endocrine tumours: correlation with nuclear translocation of beta-catenin and chromosomal instability.

The role of Wnt pathway in digestive endocrine tumours is debated. The aim of this work is to investigate key players in Wnt pathway by a multimodal approach. Sixty cases (49 well-differentiated and 11 poorly differentiated) were investigated for methylation of adenomatous polyposis coli (APC) and E-cadherin promoters, the loss of heterozygosity (LOH) at APC locus and beta-catenin and E-cadherin expression by immunohistochemistry. Tumours showing altered beta-catenin localization were tested for beta-catenin and APC mutations. APC promoter methylation was restricted to gastroduodenal tumours (21 out of 59, 36%), prevalent in poorly differentiated carcinomas (P=0.042) and correlating with aggressive features (high histology grade, P<0.02; tumour death, P=0.026; high fractional allelic loss, P=0.002, in turn correlating with short survival, P=0.017). LOH at APC locus was found in 14 out of 53 cases (26%, 10 gastroduodenal and 4 colorectal), prevalent in poorly differentiated carcinomas (P=0.002) and correlating with histology grade (P=0.012). beta-catenin abnormal expression was found in 41 out of 54 cases (76%), with nuclear staining correlating with APC alteration (P=0.047) and short survival (P=0.006). APC, but not beta-catenin, gene mutations were found (7 out of 35 tumours), 4 of which in the midgut. E-cadherin promoter methylation was rarely detected (2 out of 52 cases), with cytoplasmic expression in 18 out of 43 cases (42%), not correlating with any clinico-pathological feature. In conclusion, Wnt pathway alterations, as represented by abnormal beta-catenin localization, are common events in digestive endocrine tumours, but only nuclear expression correlates with tumour aggressiveness. Though with different alteration mechanisms according to anatomical site, APC plays a major role in Wnt pathway activation and in determining the high chromosomal instability observed in aggressive endocrine carcinomas.

Sex chromosome alterations associate with tumor progression in sporadic colorectal carcinomas.

PURPOSE: The X and Y chromosomes have been associated with malignancy in different types of human tumors. This study attempts to determine the involvement of X chromosome and pseudoautosomal regions (PAR) in sporadic colorectal carcinogenesis. EXPERIMENTAL DESIGN: An allelotyping of X chromosome in 20 premalignant and 22 malignant sporadic colorectal tumors (CRC) from female patients and an analysis of losses [loss of heterozygosity (LOH)] on PARs from 44 CRCs and 12 adenomas of male patients were carried out. In male tumors, a fluorescence in situ hybridization analysis was done to identify which sex chromosome was possibly lost. RESULTS: The LOH frequency in female CRCs was 46% with higher incidence in patients with tumor recurrence than in those who were disease-free (P < 0.01) and with a significant difference from adenomas (11%; P < 0.0001). The LOH rate of PARs in male CRCs was 37% with a frequency significantly higher in patients with recurrence (P < 0.03). These results were maintained also when data from PARs of all 66 male and female patients were cumulated (P < 0.05). LOH in PARs was significantly correlated with LOH at 5q (P < 0.01) and 18q (P < 0.01), early and late events, respectively, in colorectal carcinogenesis. Fluorescence in situ hybridization analysis in male patients with extensive PAR LOH revealed a preferential loss of the Y chromosome. CONCLUSIONS: Our data suggest a role for sex chromosome deletions in the malignant progression of sporadic CRCs and support the presence in the PARs of putative tumor suppressor genes involved in the progression of human sporadic CRCs.

Involvement of HER-2/neu and metastasis-related proteins in the development of ileal neuroendocrine tumors.

HER-2/neu overexpression and/or gene amplification occurs in several human malignancies, frequently correlates with tumor aggressiveness, and provides the basis for treatment with trastuzumab. Among neuroendocrine neoplasms (NEN) of the gastroenteropancreatic (GEP) tract, ileal neuroendocrine tumors show peculiar features of malignancy with frequent metastases at the diagnosis. We investigated the overexpression and/or amplification of HER-2/neu and the involvement of the metastasis-related proteins c-Met, MTA-1, and VEGF in 24 primary ileal NEN by immunohistochemistry and fluorescence in situ hybridization (FISH). Data were compared with those of 43 GEP endocrine tumors of other sites. All primary ileal NEN showed an intense membranous and cytoplasmic immunostaining for HER-2/neu. According to the breast cancer scoring system, 17% of ileal carcinoids showed a score of 3+ and 71% with a score of 2+ with a significant difference respect the non-ileal GEP endocrine tumors (p < 0.0000). FISH analysis revealed chromosome 17 polysomy in 33% of 2+/3+ ileal tumors but not HER-2/neu gene amplification. The c-Met and MTA-1 but not VEGF were overexpressed in almost all ileal NEN, whereas VEGF presented more frequently a normal staining. The comparisons with the other GEP NEN demonstrated significant differences for all the three proteins (p < 0.0000, p < 0.0002, and p < 0.001, respectively). These findings suggest that in ileal NEN, HER-2/neu overexpression plays a role in the carcinogenetic process and by triggering the altered expression of c-Met and MTA-1, may activate the molecular pathway(s) promoting tumor progression and metastasis development. Ileal HER-2/neu overexpressing neuroendrocrine tumors may constitute potential candidates for target therapy with specific humanized monoclonal antibodies.

Gastrointestinal stromal tumor and other primary metachronous or synchronous neoplasms as a suspicion criterion for syndromic setting.

Gastrointestinal stromal tumors (GISTs) may be sporadic or inherited. Although KIT and PDGFRA activating mutations are the oncogenic mechanisms in most sporadic and inherited GISTs, a small subset of GISTs are negative for both. Besides the classical Familial GIST Syndrome, GIST can occur as part of multi-neoplastic disease. The present study was designed to analyze the synchronous and metachronous tumors developed among GIST patients assessed by our institution for GIST Syndrome setting recognition. Patients (n=141) with primary GIST (77 men and 64 women) were recruited between 1988 and 2007 and their clinical and pathological records were reviewed. Mutation analysis of KIT, PDGFRA, NF1 and MMR genes was performed on somatic and peripheral blood DNA. GISTs occurred associated with other primary malignancies in 46 of 141 (32.6%) patients. The most common neoplasms were gastrointestinal and genitourinary. A novel exon 6 germline large deletion of NF1 was identified in the NF1/GIST kindred. The development of GIST associated with other neoplasms is common and diagnosis of peculiar benign associated-neoplasms warrants the search for familial cancer susceptibility. In particular, syndromic or familial settings have to be suspected in the presence of neurofibroma or lung chordoma in C-KIT and PDGFRA negative GIST patients.