Identification and characterization of L985P, a CD20 related family member over-expressed in small cell lung carcinoma.
We recently reported on the use of cDNA subtraction combined with microarray based expression analysis for identifying genes that are differentially over-expressed in small cell lung carcinoma. One of the several hundred genes identified using this approach was termed L985P and its molecular characterization is described in this report. The differential over-expression of L985P mRNA in SCLC, as determined by microarray analysis, was confirmed by real-time RT-PCR and Northern blot analysis. Immunohistochemical analyses show that L985P protein is highly expressed in SCLC with very restricted expression observed in normal lung, which was confined to the apical region of the ciliated bronchiolar epithelium. Flow cytometric and immunohistochemical analysis showed that L985P was localized to the cell surface. Sequence homology comparison indicated that L985P is identical to MS4A8B, a member of the recently described membrane-spanning 4-domain family, subfamily A (MS4A) gene family. The MS4A gene family currently consists of greater than 20 distinct human and mouse proteins that include CD20 and FcepsilonRIbeta. Both CD20 and FcepsilonRIbeta are involved in signaling events that regulate diverse cellular functions including cell growth regulation and differentiation. Collectively, the results presented herein demonstrate that L985P is differentially over-expressed in SCLC and may have potential clinical utility as an immunotherapeutic target for the treatment of SCLC.
Bangur
Chaitanya S
CS
Corixa Corporation, 1900 9th Avenue, Suite 1100, Seattle, WA 98101, USA.
Johnson
Jeffrey C
JC
Switzer
Ann
A
Wang
Yi-Hong
YH
Hill
Beth
B
Fanger
Gary R
GR
Wang
Tongtong
T
Retter
Marc W
MW
D015703:Antigens, CD / Q000096:biosynthesis* / Q000235:genetics*; D018288:Carcinoma, Small Cell / Q000235:genetics* / Q000473:pathology; D002454:Cell Differentiation; D049109:Cell Proliferation; D020869:Gene Expression Profiling; D006801:Humans; D007167:Immunotherapy; D008175:Lung Neoplasms / Q000235:genetics* / Q000473:pathology; D008565:Membrane Proteins; D017455:Receptors, IgE / Q000096:biosynthesis* / Q000235:genetics*; D015398:Signal Transduction; D014407:Tumor Cells, Cultured
D015703:Antigens, CD; C498468:L985P protein, human; C438731:MS4A7 protein, human; D008565:Membrane Proteins; D017455:Receptors, IgE