Metastasis is one of the most urgent issues in breast cancer patients. One of the factors necessary in the migration process is the remodeling of the extracellular matrix (ECM). Metalloproteinases (MMPs) can break down the elements of the ECM, which facilitates cell movement. Many highly aggressive tumors are characterized by high levels of MMPs. In the case of breast cancer, the association between MMP-9 and the migration potential and invasiveness of cells has been demonstrated. In addition, reports indicating increased migration of breast cancer cells after the administration of the commonly used cytostatic cyclophosphamide (CP) are particularly disturbing. Hence, our research aimed to assess the effect of CP treatment on MDA-MB-231 and MCF-7 cells and how this response is influenced by the downregulation of the MMP-9 level. The obtained results suggest that CP causes a decrease in the survival of breast cancer cells of various invasiveness, and the downregulation of MMP-9 enhances this effect, mainly by inducing apoptosis. Moreover, in the group of MMP-9 siRNA-transfected CP-treated cells, a more severe reduction in invasion and migration of cells of both lines was observed, as indicated by the migration and invasion transwell assays and Wound healing assay. Hence, we suggest that CP alone may not result in satisfactory therapeutic effects. On the other hand, the use of combination therapy targeting MMP-9, together with the CP, could improve the effectiveness of the treatment. Additionally, we confirmed a relationship between the levels of MMP-9 and cytokeratin 19 (CK19).

Extracellular vesicles (EVs) serve as central mediators in communication between tumor and non-tumor cells. These interactions are largely dependent on the function of the endothelial barrier and the set of receptors present on its surface, as endothelial cells (ECs) are a plenteous source of EVs. The molecular basis for EV secretion and action in the tumor microenvironment (TME) has not been fully elucidated to date. Emerging evidence suggests a prominent role of inflammatory pathways in promoting tumor progression and metastasis. Although transforming growth factor β (TGF-β) is a cytokine with strong immunomodulatory and protective activity in benign and early-stage cancer cells, it plays a pro-tumorigenic role in advanced cancer cells, which is known as the “TGF-β paradox”. Thus, the aim of this review is to describe the correlation between EV release, TGF-β-dependent inflammation, and dysregulation of downstream TGF-β signaling in the context of cancer development.

Homeostasis is a fundamental property of biological systems consisting of the ability to maintain a dynamic balance of the environment of biochemical processes. The action of endogenous and exogenous factors can lead to internal balance disorder, which results in the activation of the immune system and the development of inflammatory response. Inflammation determines the disturbances in the structure of the vessel wall, connected with the change in their diameter. These disorders consist of accumulation in the space between the endothelium and the muscle cells of low-density lipoproteins (LDL), resulting in the formation of fatty streaks narrowing the lumen and restricting the blood flow in the area behind the structure. The effect of inflammation may also be pathological dilatation of the vessel wall associated with the development of aneurysms. Described disease entities strongly correlate with the increased migration of immune cells. Recent scientific research indicates the secretion of specific vesicular structures during migration activated by the inflammation. The review focuses on the link between endothelial dysfunction and the inflammatory response and the impact of these processes on the development of disease entities potentially related to the secretion of extracellular vesicles (EVs).

The immune system, unlike other systems, must be flexible and able to “adapt” to fully cope with lurking dangers. The transition from intracorporeal balance to homeostasis disruption is associated with activation of inflammatory signaling pathways, which causes modulation of the immunology response. Chemotactic cytokines, signaling molecules, and extracellular vesicles act as critical mediators of inflammation and participate in intercellular communication, conditioning the immune system’s proper response. Among the well-known cytokines allowing for the development and proper functioning of the immune system by mediating cell survival and cell-death-inducing signaling, the tumor necrosis factor α (TNF-α) and transforming growth factor β (TGF-β) are noteworthy. The high bloodstream concentration of those pleiotropic cytokines can be characterized by anti- and pro-inflammatory activity, considering the powerful anti-inflammatory and anti-oxidative stress capabilities of TGF-β known from the literature. Together with the chemokines, the immune system response is also influenced by biologically active chemicals, such as melatonin. The enhanced cellular communication shows the relationship between the TGF-β signaling pathway and the extracellular vesicles (EVs) secreted under the influence of melatonin. This review outlines the findings on melatonin activity on TGF-β-dependent inflammatory response regulation in cell-to-cell communication leading to secretion of the different EV populations.

Background: It has yet to be determined whether the immunocytological profile of the bronchoalveolar lavage (BAL) in respiratory post-COVID syndrome (PCS) reflects the risk of persistent interstitial lung disease (ILD), including pulmonary fibrosis. In this study, we aimed to assess the prognostic value of the BAL cytoimmunologic profile in PCS-related ILD. Materials and Methods: We enrolled 58 non-smoking patients with a history of COVID-19 and new-onset ILD, divided into PCS remission and PCS persistence groups based on clinical data, including repeated computed tomography and pulmonary function tests. We phenotyped BAL major T cell subsets, immune checkpoints (including programmed cell death-1, PD1), and markers of Th1/Th2/Th17 polarization. Results: The PCS groups compared to the control showed increased total cell, lymphocyte, and neutrophil counts and a high BAL neutrophil:lymphocyte ratio (NLR). PCS persistence compared to the controls presented an increased neutrophil count (26 [17–36] vs. 2.6 [1.9–5.4] 103/mL, median [Q1–Q3], p < 0.001) and percentage, BAL NLR (0.77 [0.26–1.63] vs. 0.21 [0.17–0.31], p < 0.0001), CD8+PD1+ cell percentage (43.5 [34–60.5] vs. 24.5 [22–44]%, p = 0.045), and a decreased CD4:CD8 ratio. A high percentage of CD4+CD196+CD183 cells (relevant to Th17 activity, 6.2 [2.0–9.4] vs. 1.2 [0.7–2.7]%, p = 0.02) and increased BAL supernatant elevated IL-8 levels (62.5 [16–243] vs. 10.9 [3.44–32] pg/mL, p = 0.002) were found in the PCS persistence vs. control groups. In the total PCS group, predicted values of Vital Capacity (VC) [16–243] and Diffusing Lung Capacity for CO (DLCO) correlated negatively with BAL NLR; VC correlated negatively with BAL CD8+PD1+; and DLCO correlated positively with the CD4:CD8 ratio. Conclusions: Worse prognosis in PCS is associated with higher BAL NLR, BAL neutrophilia, an elevated percentage of CD8+PD1+ lymphocytes, and a decline in the CD4:CD8 ratio. Th17 cells and IL-8 participate in lung PCS persistence.

Cell-penetrating peptides (CPPs), due to their effectiveness and low cytotoxicity, are of increasing interest in the context of the transport of macromolecules to the cells. The simplest and safest method seems to be the non-covalent binding of CPP and cargo molecules. However, it requires the optimization of the reaction conditions. The study aimed to determine the effectiveness and cytotoxicity of the Pep-1, KALA, and TAT proteins as well as the NLS [47–55] and NLS [47–56] sequences derived from the Simian Vacuolating 40 (SV40) T-antigen in the context of the transport of the pmaxGFP plasmid to primary human coronary artery endothelial cells. The results are presented in the form of extensive photographic documentation, which shows significant differences in the efficiency of the transfection process between electroporation and the use of CPPs. The study presents negative results in which, despite the manipulation of various parameters (incubation time, incubation temperature, culture time, charge ratio, plasmid concentration), results similar to electroporation were not obtained.