Tuberculous Pericarditis in Childhood: A Case Report and a Systematic Literature Review

Tuberculous pericarditis (TBP) is an important cause of pericarditis worldwide while being infrequent in childhood, especially in low-TB-incidence countries. We report a case of TBP and provide a systematic review of the literature, conducted by searching PubMed, Scopus, and Cochrane to find cases of TBP in pediatric age published in the English language between the year 1990 and the time of the search. Of the 587 search results obtained, after screening and a backward citation search, 45 studies were selected to be included in this review, accounting for a total of 125 patients. The main signs and symptoms were fever, cough, weight loss, hepatomegaly, dyspnea, and increased jugular venous pressure or jugular vein turgor. A definitive diagnosis of TBP was made in 36 patients, either thanks to microbiological investigations, histological analysis, or both. First-line antitubercular treatment (ATT) was administered in nearly all cases, and 69 children underwent surgical procedures. Only six patients died, and only two died of TBP. TBP in childhood is relatively uncommon, even in high-TB-prevalence countries. Clinical manifestations, often suggestive of right-sided cardiac failure, are subtle, and diagnosis is challenging. TBP has an excellent prognosis in childhood; however, in a significant proportion of cases, invasive surgical procedures are necessary.

Mucosal Relapse of Visceral Leishmaniasis in a Child with SARS-CoV-2 Infection

Leishmaniasis is a vector-borne disease caused by protozoan parasites of the genus Leishmania and is transmitted through the bite of infected female sandflies. In the Mediterranean region, visceral leishmaniasis is caused by Leishmania. infantum, and it is usually responsible for symptoms such as fever, pancytopenia and enlargement of the liver and spleen. Relapse is rare in immunocompetent patients as much as the mucous involvement. We present a rare case of mucosal relapse of visceral leishmaniasis in a child with SARS-CoV-2 infection and perform an extensive review of the literature about leishmaniasis relapses in children. Atypical mucosal involvement during Leishmaniasis relapse is an eventuality in pediatric patients. Clinical follow-up and periodic PCR tests must be considered essential for the early recognition and treatment of an eventual relapse.

Streptococcus mitis as a New Emerging Pathogen in Pediatric Age: Case Report and Systematic Review

Streptococcus mitis, a normal inhabitant of the oral cavity, is a member of Viridans Group Streptococci (VGS). Generally recognized as a causative agent of invasive diseases in immunocompromised patients, S. mitis is considered to have low pathogenic potential in immunocompetent individuals. We present a rare case of sinusitis complicated by meningitis and cerebral sino-venous thrombosis (CSVT) caused by S. mitis in a previously healthy 12-year-old boy with poor oral health status. With the aim of understanding the real pathogenic role of this microorganism, an extensive review of the literature about invasive diseases due to S. mitis in pediatric patients was performed. Our data define the critical role of this microorganism in invasive infections, especially in immunocompetent children and in the presence of apparently harmful conditions such as sinusitis and caries. Attention should be paid to the choice of therapy because of VGS's emerging antimicrobial resistance patterns.

Trop-2 induces ADAM10-mediated cleavage of E-cadherin and drives EMT-less metastasis in colon cancer

We recently reported that activation of Trop-2 through its cleavage at R87-T88 by ADAM10 underlies Trop-2–driven progression of colon cancer. However, the mechanism of action and pathological impact of Trop-2 in metastatic diffusion remain unexplored. Through searches for molecular determinants of cancer metastasis, we identified TROP2 as unique in its up-regulation across independent colon cancer metastasis models. Overexpression of wild-type Trop-2 in KM12SM human colon cancer cells increased liver metastasis rates in vivo in immunosuppressed mice. Metastatic growth was further enhanced by a tail-less, activated ΔcytoTrop-2 mutant, indicating the Trop-2 tail as a pivotal inhibitory signaling element. In primary tumors and metastases, transcriptome analysis showed no down-regulation of CDH1 by transcription factors for epithelial-to-mesenchymal transition, thus suggesting that the pro-metastatic activity of Trop-2 is through alternative mechanisms. Trop-2 can tightly interact with ADAM10. Here, Trop-2 bound E-cadherin and stimulated ADAM10-mediated proteolytic cleavage of E-cadherin intracellular domain. This induced detachment of E-cadherin from β-actin, and loss of cell-cell adhesion, acquisition of invasive capability, and membrane-driven activation of β-catenin signaling, which were further enhanced by the ΔcytoTrop-2 mutant. This Trop-2/E-cadherin/β-catenin program led to anti-apoptotic signaling, increased cell migration, and enhanced cancer-cell survival. In patients with colon cancer, activation of this Trop-2–centered program led to significantly reduced relapse-free and overall survival, indicating a major impact on progression to metastatic disease. Recently, the anti-Trop-2 mAb Sacituzumab govitecan-hziy was shown to be active against metastatic breast cancer. Our findings define the key relevance of Trop-2 as a target in metastatic colon cancer.

Abstract 2851: Trop-2 inactivates E-cadherin for metastatic diffusion in the absence of EMT

Trop-2 is a type I transmembrane glycoprotein, which is overexpressed in the majority of carcinomas, where it drives tumor cell proliferation. In its mature, glycosylated/functionally-competent form, Trop-2 associates with worse prognosis. A global quest was conducted for identifying decisive drivers of cancer metastasis. Cancer cell spheroids, wound healing and cell aggregation assays were utilized to assess cell-cell adhesion capacity. Immunofluorescence confocal microscopy and flow cytometry analysis were utilized to quantify expression of target signaling proteins, IHC analysis quantified the expression of target molecules in primary tumors and metastases. Pre-clinical models of orthotopic growth of colon cancer and metastatic diffusion to the liver were utilized. Xenotransplant transcriptome profiling analyzed transcription of EMT-related determinants. This led us to identify Trop-2 as a unique upregulated gene in colon cancer metastasis. Trop-2 was here shown to bind highly-expressed E-cadherin at the cell membrane. Trop-2 binding released E-cadherin from the cytoskeleton, inhibited cell-cell adhesion functions and activated signaling through β-catenin. This occurred in the absence of transcriptional downregulation of the CDH1 gene by EMT-associated transcription factors. The Trop-2/E-cadherin/β-catenin program was shown to lead to anti-apoptotic signaling, increased cell migration and enhanced cancer cell survival. In an orthotopic model of colon cancer, Trop-2 caused metastatic diffusion to the liver. The Trop-2-led E-cadherin-inactivation metastasis program was then found to induce metastatic relapse and shorter overall survival of colon cancer patients. Corresponding impact was indicated on breast, colon, ovary, uterus, stomach cancer metastatic diffusion, for broad impact on metastatic diffusion in human cancer.

Acknowledgments:Support was provided by grants of Italian Ministry of Development (MI01_00424) and of University and Research (SCN_00558). M.T. was supported by the Programma Per Giovani Ricercatori “Rita Levi Montalcini” (Grant PGR12I7N1Z).

Citation Format: Saverio Alberti, Emanuela Guerra, Valeria Relli, Rossano Lattanzio, Martina Ceci, Khouloud Boujnah, Valeria Garbo, Antonino Moschella, donato F. Altomare, Raffaella Depalo, Marco Trerotola. Trop-2 inactivates E-cadherin for metastatic diffusion in the absence of EMT [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2851.

Abstract PD15-04: Trop-2 inactivation of E-cadherin drives triple negative breast cancer relapse

Hundreds of proteins/genes have been linked to the metastatic phenotype. However, consistent markers of tumour aggressiveness and metastatic potential in breast cancer patients were not identified, not even including proteomic analysis and large-scale genome sequencing.Metastasis-associated genes were predicted to include not only drivers of the metastatic phenotype, but also secondary events, together with adaptive, counterbalancing changes. Thus, to identify candidates with a required role in metastatic diffusion, we looked for genes that were concordantly dysregulated across orthogonal cancer metastasis settings. This led us to identify Trop-2 as uniquely upregulated and associated to metastasis in experimental models of breast cancer, as well as in other solid tumors. We identified functional inactivation of E-cadherin by Trop-2 as the main motor of metastatic diffusion of such metastatic systems. Trop-2 binding to E-cadherin inactivated its cell-cell adhesion function, through release from the cytoskeleton, for activation of β-catenin transcriptional activity. This led to anti-apoptotic signaling, increased cell migration capacity and enhanced cancer cell survival. We showed that this mechanism led to metastatic diffusion of xenotransplants growing in immunosuppressed mice. An E-cadherin-inactivation metastasis program was then shown to be recapitulated in breast cancer patients, as well as in other solid tumors, over 24 independent case series, encompassing 13,042 primary tumours. Aggressive triple-negative breast cancers were shown to be driven toward global relapse by Trop-2 overexpression, through E-cadherin inactivation and activation of β-catenin transcriptional activity. No disease recurrence was observed in control cases over +12 years of follow-up. These finding lead to a novel paradigm of a Trop-2-driven, E-cadherin-inactivation program as a main metastasis driver in solid tumors. This may open far-reaching perspectives in diagnostic procedures and anti-cancer therapies.

Citation Format: Saverio Alberti, Marco Trerotola, Valeria Relli, Rossano Lattanzio, Martina Ceci, Khouloud Boujnah, Valeria Garbo, Antonino Moschella, Patrizia Querzoli, Massimo Pedriali, Laura Antolini, Emanuela Guerra. Trop-2 inactivation of E-cadherin drives triple negative breast cancer relapse [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD15-04.