CD44s Assembles Hyaluronan Coat on Filopodia and Extracellular Vesicles and Induces Tumorigenicity of MKN74 Gastric Carcinoma Cells.

CD44 is a multifunctional adhesion molecule typically upregulated in malignant, inflamed and injured tissues. Due to its ability to bind multiple ligands present in the tumor microenvironment, it promotes multiple cellular functions related to tumorigenesis. Recent data has shown that CD44 and its principal ligand hyaluronan (HA) are carried by extracellular vesicles (EV) derived from stem and tumor cells, but the role of CD44 in EV shedding has not been studied so far. To answer this question, we utilized CD44-negative human gastric carcinoma cell line MKN74 manipulated to stably express CD44 standard form (CD44s). The effect of CD44s expression on HA metabolism, EV secretion, morphology and growth of these cells was studied. Interestingly, HAS2 and HYAL2 expression levels were significantly upregulated in CD44s-expressing cells. Cell-associated HA levels were significantly increased, while HA levels in the culture medium of CD44s-positive cells was lower compared to CD44s-negative MOCK cells. CD44s expression had no significant effect on the proliferation capacity of cells, but cells showed diminished contact inhibition. Superresolution imaging revealed that CD44s and HA were accumulated on filopodia and EVs secreted from CD44s-positive cells, but no differences in total numbers of secreted EV between CD44s-negative and -positive cells was detected. In 3D cultures, CD44s-expressing cells had an enhanced invasion capacity in BME gel and increased spheroidal growth when cultured in collagen I gel. No significant differences in mitotic activity, tumor size or morphology were detected in CAM assays. However, a significant increase in HA staining coverage was detected in CD44s-positive tumors. Interestingly, CD44s-positive EVs embedded in HA-rich matrix were detected in the stromal areas of tumors. The results indicate that CD44s expression significantly increases the HA binding capacity of gastric cancer cells, while the secreted HA is downregulated. CD44s is also carried by EVs secreted by CD44s-expressing cells. These findings highlight the potential usefulness of CD44s and its ligands as multipurpose EV biomarkers, because they are upregulated in inflammatory, injured, and cancer cells and accumulate on the surface of EVs secreted in these situations.

Exploring aftercare programs following outpatient musculoskeletal physical therapy: a case series report.

Aftercare programs allow patients to continue to exercise with supervision following discharge from physical therapy. Although not yet widespread in clinical practice, aftercare programs represent a growing trend following outpatient physical therapy settings in the United States. The purpose of this study was to explore and describe the characteristics, implementation, and impact of contemporary aftercare programs in a selected sample of outpatient physical therapy settings. A purposeful sample of three aftercare program and four clients were interviewed to provide the descriptive data for this study. Each client was also later interviewed at 3-4 months and again at 6 months. A general health outcomes measurement tool (SF-36) and musculoskeletal regional outcomes tools also were used to measure health status and function. Directors of the three programs cited similar rationales for starting their aftercare programs. However, specific features and goals of the three aftercare programs varied, as did utilization and participation. Clients were generally pleased with their aftercare involvement, and they demonstrated clinically important improvements on outcome measures of function and health-related quality of life in addition to subjective reports of satisfaction. Aftercare programs are an emerging clinical trend following physical therapy, and this study provides an initial description of the development, implementation, and effectiveness of such programs. Future study should investigate a greater variety of aftercare settings and larger samples of participants and should also further examine how well aftercare programs promote health and wellness.