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Breast cancer (BC) is the second cause of cancer-related deceases in the worldwide female population. Despite the successful treatment advances, 25% of BC develops resistance to current therapeutic regimens, thereby remaining a major hurdle for patient management. Current therapies, targeting the molecular events underpinning the adaptive resistance, still require effort to improve BC treatment. Using BC sphere cells (BCSphCs) as a model, here we showed that BC stem-like cells express high levels of Myc, which requires the presence of the multifunctional DNA/RNA binding protein Sam68 for the DNA-damage repair. Analysis of a cohort of BC patients displayed that Sam68 is an independent negative factor correlated with the progression of the disease. Genetic inhibition of Sam68 caused a defect in PARP-induced PAR chain synthesis upon DNA-damaging insults, resulting in cell death of TNBC cells. In contrast, BC stem-like cells were able to survive due to an upregulation of Rad51. Importantly, the inhibition of Rad51 showed synthetic lethal effect with the silencing of Sam68, hampering the cell viability of patient-derived BCSphCs and stabilizing the growth of tumor xenografts, including those TNBC carrying BRCA mutation. Moreover, the analysis of Myc, Sam68 and Rad51 expression demarcated a signature of a poor outcome in a large cohort of BC patients. Thus, our findings suggest the importance of targeting Sam68-PARP1 axis and Rad51 as potential therapeutic candidates to counteract the expansion of BC cells with an aggressive phenotype.

Despite advances in the curative approach, the survival rate of advanced colorectal cancer (CRC) patients is still poor, which is likely due to the emergence of cancer cell clones resistant to the available therapeutic options. We have already shown that CD44v6-positive CRC stem cells (CR-CSCs) are refractory toward standard anti-tumor therapeutic agents due to the activation of the PI3K pathway together with high HER2 expression levels. Tumor microenvironmental cytokines confer resistance to CR-CSCs against HER2/PI3K targeting by enhancing activation of the MAPK pathway. Here, we show that the CSC compartment, spared by BRAF inhibitor-based targeted therapy, is associated with increased expression levels of CD44v6 and Myc and retains boosted clonogenic activity along with residual tumorigenic potential. Inhibition of Myc transcription, downstream of the MAPK cascade components, and PI3K pathway activity was able to overcome the protective effects of microenvironmental cytokines, affecting the survival and the clonogenic activity of CR-CSCs, regardless of their mutational background. Likewise, the double targeting induced stabilization of mouse tumor avatars. Altogether, these data outline the rationale for dual kinase targeting of CR-CSCs to prevent their adaptive response, which would lead to disease progression.

Despite intense research and clinical efforts, patients affected by advanced colorectal cancer (CRC) have still a poor prognosis. The discovery of colorectal (CR) cancer stem cell (CSC) as the cell compartment responsible for tumor initiation and propagation may provide new opportunities for the development of new therapeutic strategies. Given the reduced sensitivity of CR-CSCs to chemotherapy and the ability of bone morphogenetic proteins (BMP) to promote colonic stem cell differentiation, we aimed to investigate whether an enhanced variant of BMP7 (BMP7v) could sensitize to chemotherapy-resistant CRC cells and tumors. Thirty-five primary human cultures enriched in CR-CSCs, including four from chemoresistant metastatic lesions, were used for in vitro studies and to generate CR-CSC-based mouse avatars to evaluate tumor growth and progression upon treatment with BMP7v alone or in combination with standard therapy or PI3K inhibitors. BMP7v treatment promotes CR-CSC differentiation and recapitulates the cell differentiation-related gene expression profile by suppressing Wnt pathway activity and reducing mesenchymal traits and survival of CR-CSCs. Moreover, in CR-CSC-based mouse avatars, BMP7v exerts an antiangiogenic effect and sensitizes tumor cells to standard chemotherapy regardless of the mutational, MSI, and CMS profiles. Of note, tumor harboring PIK3CA mutations were affected to a lower extent by the combination of BMP7v and chemotherapy. However, the addition of a PI3K inhibitor to the BMP7v-based combination potentiates PIK3CA-mutant tumor drug response and reduces the metastatic lesion size. These data suggest that BMP7v treatment may represent a useful antiangiogenic and prodifferentiation agent, which renders CSCs sensitive to both standard and targeted therapies.

Background: Hidradenitis suppurativa (HS) is a chronic, relapsing, inflammatory skin disease characterized by painful inflamed nodules, recurrent abscesses and fistulas located in apocrine gland–bearing body sites. The negative impact of HS on patient's quality of life (QoL) has been reported to be greater than other dermatologic conditions as psoriasis and atopic eczema, and its improvement is an important goal in disease management. Nowadays, there are no specific validated QoL instruments available for HS and generic dermatologic questionnaires are used. Objective: The objective of this study was to demonstrate the validity, reliability and responsiveness of HIDRAdisk, a new innovative tool designed for rapid assessment of HS burden and, at the same time, an intuitive graphic visualization of the measurement outcome. Methods: A multicentre, longitudinal, observational study was conducted to validate the HIDRAdisk compared with other validated questionnaires [Skindex-16, Dermatology Life Quality Index (DLQI), Work Productivity and Activity Impairment–General Health (WPAI:GH)] and to evaluate its correlation with disease severity in Italian patients with any degree of HS severity, as measured by Hurley stage and HS Physician Global Assessment (HS-PGA). Results: A total of 140 patients (59% women; mean age 34.9 ± 11.0 years) were enrolled in 27 dermatologic centres. HIDRAdisk showed a strong correlation with Skindex-16 and DLQI, and a good one with WPAI:GH (correlation coefficient: 0.7568, 0.6651 and 0.5947, respectively) and a statistically significant correlation with both Hurley stage and HS-PGA. Very good internal consistency (Cronbach coefficient >0.80; intraclass correlation coefficient >0.6), with correlation between the 10 items, good test–retest reliability (Spearman correlation coefficient, 0.8331; P < 0.0001) and responsiveness to changes were demonstrated. Conclusion: Our study shows that HIDRAdisk, a short and innovativ