PubMed Health⌕ Search

Biomedical subjects

A Shanafelt

Publications and source records attributed to A Shanafelt.

4 recordsLinked to original sources

The role of CXC chemokines in the regulation of angiogenesis in non-small cell lung cancer.

Angiogenesis is a critical component of tumor biology. In recent years newer techniques of cell and molecular biology have led to important advances in our understanding of this process. The regulation of angiogenesis depends on a balance between the activity of local factors that promote (angiogenic factors) or inhibit (angiostatic factors) neovascularization. Nowhere is this paradigm of a balance more apparent than in the study of tumor-associated angiogenesis. Tumors promote angiogenesis through a combination of overexpression of angiogenic factors and local inhibition of angiostatic factors. This strategy leads to an angiogenic environment that promotes tumor growth and metastases. Our laboratory has focused studies on the role of the CXC chemokine family in the regulation of angiogenesis by non-small cell lung cancer (NSCLC). In this article, we review our findings that the CXC chemokine family is composed of members that are either angiogenic or angiostatic. We have found that in NSCLC an imbalance exists in the expression of these factors that favors tumor-derived angiogenesis, and therefore tumor growth and metastases. Furthermore, when this imbalance is corrected to reduce the presence of angiogenic factors or increase the presence of angiostatic factors, tumor growth and metastases are reduced.

Animals↗

CD38-mediated ribosylation of proteins.

The lymphocyte cell-surface Ag CD38 catabolizes NAD to adenosine 5' diphosphoribose (ADPR) and cyclic ADPR (cADPR). We show here that the soluble extracellular domain of CD38 (sCD38) mediates ADP ribosylation of several proteins. This was demonstrated by mass spectrometric analyses which revealed the addition of mass in units of 541.1 Da to these proteins, presumably corresponding to the covalent attachment of one or more ADPR moieties. Separate experiments showed that the same proteins became specifically radiolabeled following incubation with [32P]NAD plus sCD38. Additionally, it is shown that sCD38 can autoribosylate. Moreover, sCD38-mediated protein ribosylation was found to occur specifically at cysteine residues, since it was effectively blocked by addition of L-cysteine but not by other amino acids, and CD38-mediated protein ribosylation could be reversed by the addition of HgCl2, which specifically cleaves thiol-glycosidic bonds. ADPR purified from the reaction of sCD38 with NAD could itself be covalently transferred to target proteins at rates similar to the sCD38-mediated reaction, indicating that the ribosylation proceeds via the generation of this reactive intermediate. In vitro mutagenesis of a catalytic Glu residue that is conserved in numerous ADP-ribosyl transferases revealed that this amino acid is also important for catalysis in CD38. These data suggest that CD38 has the potential to cause ribosylation of experimental proteins, and raises the possibility that its specific ribosylation of a currently unidentified lymphocyte protein may contribute to its array of immunoregulatory activities.

ADP-ribosyl Cyclase↗