Autophagy regulates UBC9 levels during viral-mediated tumorigenesis.

UBC9, the sole E2-conjugating enzyme required for SUMOylation, is a key regulator of essential cellular functions and, as such, is frequently altered in cancers. Along these lines, we recently reported that its expression gradually increases during early stages of human papillomavirus (HPV)-mediated cervical lesions transformation. However, a better understanding of how UBC9 is exploited by transforming viral oncoproteins is still needed. In the present study, we show that in human samples HPV drives UBC9 up-regulation also in very early steps of head and neck tumorigenesis, pointing to the important role for UBC9 in the HPV-mediated carcinogenic program. Moreover, using HPV-infected pre-cancerous tissues and primary human keratinocytes as the natural host of the virus, we investigate the pathological meaning and the cellular mechanisms responsible for UBC9 de-regulation in an oncoviral context. Our results show that UBC9 overexpression is promoted by transforming viral proteins to increase host cells' resistance to apoptosis. In addition, ultrastuctural, pharmacological and genetic approaches crucially unveil that UBC9 is physiologically targeted by autophagy in human cells. However, the presence of HPV E6/E7 oncoproteins negatively impacts the autophagic process through selective inhibition of autophagosome-lysosome fusion, finally leading to p53 dependent UBC9 accumulation during viral-induced cellular transformation. Therefore, our study elucidates how UBC9 is manipulated by HPV oncoproteins, details the physiological mechanism by which UBC9 is degraded in cells, and identifies how HPV E6/E7 impact on autophagy. These findings point to UBC9 and autophagy as novel hallmarks of HPV oncogenesis, and open innovative avenues towards the treatment of HPV-related malignancies.

Immune microenvironment dynamics in breast cancer during pregnancy: impact of gestational age on tumor-infiltrating lymphocytes and prognosis.

Background: Breast cancer during pregnancy (PrBC) is a rare condition known for its aggressive clinical behavior. The presence of tumor-infiltrating lymphocytes (TILs) has been shown to have a significant impact on the prognosis of these patients. Despite some biological characteristics of the tumor that may differ depending on the gestational age, little is known about the dynamics of the immune landscape within the tumor microenvironment (TME) in PrBC. Therefore, in this study, our objective was to gain comprehensive insights into the relationship between gestational age at breast cancer diagnosis and the composition of the TME. Methods: n = 108 PrBC were selected from our institutional registry and categorized based on the gestational age by trimester. For all cases, TILs were profiled according to the International TILs Working Group recommendations, and subtyped by CD4, CD8, and forkhead box P3 (FOXP3) immunohistochemistry. PD-L1 was tested according to the combined positive score (CPS) using the IHC 22C3 pharmDx assay, with a cutoff value of ≥10 for positivity. The statistical approach encompassed Fisher's and Chi-squared tests, with appropriate adjustments for multiple comparisons, logistic regression models, and survival analyses based on the Kaplan-Meier method. Results: The proportion of patients with poorly differentiated (G3) neoplasms increased as the gestational age advanced (first trimester, n = 25, 56.8%; second trimester, n = 27, 69.2%; third trimester, n = 21, 87.5%; p = 0.03). The histologic subtypes as well as the hormone receptor (HR) and HER2 status did not show significant changes across different pregnancy trimesters. In the HR+/HER2- subtype, there was a higher proportion of tumors with high/moderate TILs in the early phases of pregnancy, similar to FOXP3 expression (TILs: first trimester, n = 10, 35.7%; second trimester, n = 2, 10.5%; third trimester, n = 0; p = 0.02; FOXP3: first trimester, n = 10, 40%; second trimester, n = 3, 15.8%; third trimester, n = 0; p = 0.03). The median follow-up for our cohort was 81 months. Patients who relapsed after a breast cancer diagnosis during the first trimester were more frequently PD-L1-negative, unlike those with no disease recurrence (n = 9, 100% vs. n = 9, 56.3%; p = 0.03; hormone therapy and n = 9, 100% vs. n = 7, 53.9%; p = 0.02; chemotherapy). No statistically significant differences were seen among the three trimesters in terms of survival outcome. Conclusion: The TME dynamics of HR+/HER2- PrBC vary based on gestational age, suggesting that immune tolerance expression during later gestational age could explain the increased aggressiveness of tumors diagnosed at that stage.

Breast Cancer during Pregnancy as a Special Type of Early-Onset Breast Cancer: Analysis of the Tumor Immune Microenvironment and Risk Profiles.

Breast cancer during pregnancy (PrBC) is a rare tumor with only a little information on its immune landscape. Here, we sought to characterize the cellular composition of the tumor microenvironment (TME) of PrBC and identify its differences from early-onset breast cancer (EOBC) in non-pregnant women. A total of 83 PrBC and 89 EOBC were selected from our Institutional registry and subjected to tumor-infiltrating lymphocytes (TILs) profiling and immunohistochemistry for CD4, CD8, forkhead box P3 (FOXP3), and programmed death-ligand 1 (PD-L1) (clone 22C3). A significantly lower frequency of hormone receptor (HR)-positive tumors was observed in PrBC. The prevalence of low/null PD-L1 and CD8+TILs was higher in PrBC than in the controls, specifically in HR+/HER2- breast cancers. PrBC had a significantly higher risk of relapse and disease-related death, compared to EOBC. The presence of TILs and each TIL subpopulation were significantly associated with disease relapse. Moreover, the death rate was higher in PrBC with CD8+ TILs. The TME of PrBC is characterized by specific patterns of TIL subpopulations with significant biological and prognostic roles. Routine assessment of TILs and TILs subtyping in these patients would be a valid addition to the pathology report that might help identify clinically relevant subsets of women with PrBC.

Early Breast Cancers During Pregnancy Treated With Breast-Conserving Surgery in the First Trimester of Gestation: A Feasibility Study.

Breast cancer is the most common malignancy occurring during gestation. In early-stage breast cancer during pregnancy (PrBC), breast-conserving surgery (BCS) with delayed RT is a rational alternative to mastectomy, for long considered the standard-of-care. Regrettably, no specific guidelines on the surgical management of these patients are available. In this study, we investigated the feasibility and safety of BCS during the first trimester of pregnancy in women with early-stage PrBC. All patients with a diagnosis of PrBC during the first trimester of pregnancy jointly managed in two PrBC-specialized Centers were included in this study. All patients underwent BCS followed by adjuvant radiotherapy to the ipsilateral breast after delivery. Histopathological features and biomarkers were first profiled on pre-surgical biopsies. The primary outcome was the isolated local recurrence (ILR). Among 168 PrBC patients, 67 (39.9%) were diagnosed during the first trimester of gestation. Of these, 30 patients (age range, 23-43 years; median=36 years; gestational age, 2-12 weeks; median=7 weeks; median follow-up time=6.5 years) met the inclusion criteria. The patients that were subjected to radical surgery (n=14) served as controls. None of the patients experienced perioperative surgical complications. No ILR were observed within three months (n=30), 1 year (n=27), and 5 years (n=18) after surgery. Among the study group, 4 (12.3%) patients experienced ILR or new carcinomas after 6-13 years, the same number (n=4) had metastatic dissemination after 3-7 years. These patients are still alive and disease-free after 14-17 years of follow-up. The rate of recurrences and metastasis in the controls were not significantly different. The findings provide evidence that BCS in the first trimester PrBC is feasible and reasonably safe for both the mother and the baby.

Redox-Mediated Suberoylanilide Hydroxamic Acid Sensitivity in Breast Cancer.

AIMS: Vorinostat (suberoylanilide hydroxamic acid; SAHA) is a histone deacetylase inhibitor (HDACi) approved in the clinics for the treatment of T-cell lymphoma and with the potential to be effective also in breast cancer. We investigated the responsiveness to SAHA in human breast primary tumors and cancer cell lines. RESULTS: We observed a differential response to drug treatment in both human breast primary tumors and cancer cell lines. Gene expression analysis of the breast cancer cell lines revealed that genes involved in cell adhesion and redox pathways, especially glutathione metabolism, were differentially expressed in the cell lines resistant to SAHA compared with the sensitive ones, indicating their possible association with drug resistance mechanisms. Notably, such an association was also observed in breast primary tumors. Indeed, addition of buthionine sulfoximine (BSO), a compound capable of depleting cellular glutathione, significantly enhanced the cytotoxicity of SAHA in both breast cancer cell lines and primary breast tumors. INNOVATION: We identify and validate transcriptional differences in genes involved in redox pathways, which include potential predictive markers of sensitivity to SAHA. CONCLUSION: In breast cancer, it could be relevant to evaluate the expression of antioxidant genes that may favor tumor resistance as a factor to consider for potential clinical application and treatment with epigenetic drugs (HDACis).