The ubiquitin-proteasome system (UPS) is responsible for up to 90% of intracellular protein degradation. Alterations in UPS are extensively involved in the development and advancement of malignant pathologies. Thus, the components of the UPS can become potential targets for cancer therapeutics. KPC1 is an E3 ubiquitin ligase component of the UPS that regulates key pathways and processes in cancer. KPC1 sustains the ubiquitination of cytoplasmic p27, determining its elimination and transition between cell-cycle phases. KPC1 also regulates NF-κB signaling by inducing ubiquitination of p105 to allow subsequent proteasomal processing to the functional form p50. It has been shown that the KPC1-p50 duo is reduced or absent in multiple malignancies and that therapeutic reinforcement of the functional axis can exhibit significant tumor suppressor activity. Here, we highlight the potential role of KPC1 as a tumor suppressor by fully describing its crucial role in p27 signaling and the canonical NF-κB pathway.

The causes and consequences of abnormal biogenesis of extracellular vesicles (EVs) are not yet well understood in malignancies, including in breast cancers (BCs). Given the hormonal signaling dependence of estrogen receptor–positive (ER+) BC, we hypothesized that 17β-estradiol (estrogen) might influence EV production and microRNA (miRNA) loading. We report that physiological doses of 17β-estradiol promote EV secretion specifically from ER+ BC cells via inhibition of miR-149-5p, hindering its regulatory activity on SP1, a transcription factor that regulates the EV biogenesis factor nSMase2. Additionally, miR-149-5p downregulation promotes hnRNPA1 expression, responsible for the loading of let-7’s miRNAs into EVs. In multiple patient cohorts, we observed increased levels of let-7a-5p and let-7d-5p in EVs derived from the blood of premenopausal ER+ BC patients, and elevated EV levels in patients with high BMI, both conditions associated with higher levels of 17β-estradiol. In brief, we identified a unique estrogen-driven mechanism by which ER+ BC cells eliminate tumor suppressor miRNAs in EVs, with effects on modulating tumor-associated macrophages in the microenvironment.

Acquired haemophilia (AH) is a rare disorder characterized by bleeding in patients with no personal or family history of coagulation/clotting‐related diseases. This disease occurs when the immune system, by mistake, generates autoantibodies that target FVIII, causing bleeding. Small RNAs from plasma collected from AH patients (n = 2), mild classical haemophilia (n = 3), severe classical haemophilia (n = 3) and healthy donors (n = 2), for sequencing by Illumina, NextSeq500. Based on bioinformatic analysis, AH patients were compared to all experimental groups and a significant number of altered transcripts were identified with one transcript being modified compared to all groups at fold change level. The Venn diagram shows that haemoglobin subunit alpha 1 was highlighted to be the common upregulated transcript in AH compared to classical haemophilia and healthy patients. Non‐coding RNAs might play a role in AH pathogenesis; however, due to the rarity of HA, the current study needs to be translated on a larger number of AH samples and classical haemophilia samples to generate more solid data that can confirm our findings.