VA Lessons From Partnering in COVID-19 Clinical Trials.

Background: The US Department of Veterans Affairs (VA) Office of Research and Development (ORD) supports an extensive clinical trials enterprise. Until recently, external partnerships were limited. The VA's potential value as a partner became more apparent during the COVID-19 pandemic because of its large health care system, diverse patient population, and expertise in conducting clinical trials.

Ceramide-dependent regulation of human epidermal keratinocyte CD1d expression during terminal differentiation.

Human keratinocytes (KC), when cultured under conditions to remain undifferentiated or to terminally differentiate, changed their cellular distribution of CD1d. As studied by confocal microscopy, undifferentiated KC had a pool of cytoplasmic CD1d, whereas after terminal differentiation, this molecule localized in the cell membrane, which recapitulates CD1d expression in vivo. A comparison of undifferentiated and differentiated cultured KC did not reveal any differences in the association with beta(2)-microglobulin, invariant chain of class II MHC, or patterns of glycosylation, suggesting that these biochemical properties are not regulating the cellular distribution of CD1d.

The ceramide analog, B13, induces apoptosis in prostate cancer cell lines and inhibits tumor growth in prostate cancer xenografts.

Background: Apoptosis is a therapeutic target for the elimination of cancer cells. As elevations in ceramide levels induce apoptosis, there is much excitement about the use of agents that elevate ceramide levels as novel chemotherapeutic agents. Ceramidases are enzymes involved in degradation of ceramide and inhibition of ceramidase has been proposed as a mechanism to increase ceramide levels.

Cyclooxygenase inhibitors block cell growth, increase ceramide and inhibit cell cycle.

We have shown previously in a model of metastatic breast cancer that murine mammary tumor cells express both cyclooxygenase-1 (Cox-1) and Cox-2 isoforms. Growth and metastasis of these tumors in syngeneic hosts are inhibited by either selective Cox-1 (SC560) or selective Cox-2 (celecoxib) inhibitors. To gain insight into the relevant mechanisms involved in the therapeutic response, we determined the effect of Cox inhibitors on tumor cell behavior in vitro.