Extracellular vesicles cargo from head and neck cancer cell lines disrupt dendritic cells function and match plasma microRNAs.

Extracellular vesicles (EVs) are mediators of the immune system response. Encapsulated in EVs, microRNAs can be transferred between cancer and immune cells. To define the potential effects of EVs originated from squamous cell carcinoma cells on immune system response, we performed microRNA profiling of EVs released from two distinct cell lines and treated dendritic cells derived from circulating monocytes (mono-DCs) with these EVs. We confirmed the internalization of EVs by mono-DCs and the down-regulation of microRNA mRNA targets in treated mono-DCs. Differences in surface markers of dendritic cells cultivated in the presence of EVs indicated that their content disrupts the maturation process. Additionally, microRNAs known to interfere with dendritic cell function, and detected in EVs, matched microRNAs from squamous cell carcinoma patients' plasma: miR-17-5p in oropharyngeal squamous cell carcinoma, miR-21 in oral squamous cell carcinoma, miR-16, miR-24, and miR-181a circulating in both oral and oropharyngeal squamous cell carcinoma, and miR-23b, which has not been previously described in plasma of head and neck squamous cell carcinoma, was found in plasma from patients with these cancer subtypes. This study contributes with insights on EVs in signaling between cancer and immune cells in squamous cell carcinoma of the head and neck.

Cathelicidin-deficient mice exhibit increased survival and upregulation of key inflammatory response genes following cecal ligation and puncture.

Antimicrobial peptides possess a myriad of molecular properties including bacterial killing and the regulation of many aspects of innate immunity. Cathelicidins are a group of antimicrobial peptides widely investigated by the scientific community. Many studies have focused on the bactericidal and pro-inflammatory roles of cathelicidins. Because the role of endogenous cathelicidin expression remains obscure in deep-seated systemic infections, we induced sepsis in cathelicidin knockout and wild-type (WT) mice by cecal ligation and puncture, performing transcriptome screening by DNA microarray in conjunction with other immunologic assays. Cathelicidin-deficient mice showed increased survival compared to WT mice in this established experimental model of polymicrobial sepsis, in association with upregulation of certain key inflammatory response genes. Therefore, cathelicidins can exert both pro- and anti-inflammatory activities depending on the disease and cellular context. KEY MESSAGES: The role of cathelicidin in a CLP model is investigated using cathelicidin-KO mice. Cathelicidin-KO mice show an enhanced immune response and improved survival rates. An anti-inflammatory effect of cathelicidin is likely to be detrimental for CLP. Cathelicidin-KO mice show upregulation of genes associated with increased plasma levels of pro-inflammatory Ils. Cathelicidins appear to have both pro- and anti-inflammatory properties.