Melanoma differentiation associated gene-7 (mda-7): a novel anti-tumor gene for cancer gene therapy.
BACKGROUND
The mda-7 gene (melanoma differentiation associated gene-7) is a novel tumor suppressor gene. The anti-proliferative activity of MDA-7 has been previously reported. In this report, we analyze the anti-tumor efficacy of Ad-mda7 in a broad spectrum of cancer lines.


METHODS
Ad-mda7-transduced cancer or normal cell lines were assayed for cell proliferation (tritiated thymidine incorporation assay, Alamar blue assay, and trypan-blue exclusion assay), apoptosis (TUNEL, and Annexin V staining visualized by fluorescent microscopy or FACs analysis), and cell cycle regulation (Propidium Iodide staining and FACs analysis).


RESULTS
Ad-mda7 treatment of tumor cells resulted in growth inhibition and apoptosis in a temporal and dose-dependent manner. The anti-tumor effects were independent of the genomic status of p53, RB, p16, ras, bax, and caspase 3 in these cells. In addition, normal cell lines did not show inhibition of proliferation or apoptotic response to Ad-mda7. Moreover, Ad-mda7-transduced cancer cells secreted a soluble form of MDA-7 protein. Thus, Ad-mda7 may represent a novel gene-therapeutic agent for the treatment of a variety of cancers.


CONCLUSIONS
The potent and selective killing activity of Ad-mda7 in cancer cells but not in normal cells makes this vector a potential candidate for cancer gene therapy.
Mhashilkar
A M
AM
Introgen Therapeutics Inc, Houston, TX 77030, USA.
Schrock
R D
RD
Hindi
M
M
Liao
J
J
Sieger
K
K
Kourouma
F
F
Zou-Yang
X H
XH
Onishi
E
E
Takh
O
O
Vedvick
T S
TS
Fanger
G
G
Stewart
L
L
Watson
G J
GJ
Snary
D
D
Fisher
P B
PB
Saeki
T
T
Roth
J A
JA
Ramesh
R
R
Chada
S
S
D000256:Adenoviridae / Q000235:genetics; D017304:Annexin A5 / Q000378:metabolism; D015153:Blotting, Western; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002469:Cell Separation; D002874:Chromosome Mapping; D002878:Chromosomes, Human, Pair 1; D004396:Coloring Agents / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005091:Exons; D005434:Flow Cytometry; D016147:Genes, Tumor Suppressor / Q000235:genetics; D015316:Genetic Therapy / Q000379:methods*; D006133:Growth Substances / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D020287:In Situ Nick-End Labeling; D007378:Interleukins; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D009369:Neoplasms / Q000628:therapy*; D010078:Oxazines; D011419:Propidium / Q000494:pharmacology; D013936:Thymidine / Q000378:metabolism; D013997:Time Factors; D014161:Transduction, Genetic; D014343:Trypan Blue / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014966:Xanthenes; D000099180:Interleukin-24
D017304:Annexin A5; D004396:Coloring Agents; D006133:Growth Substances; D007378:Interleukins; D010078:Oxazines; D011419:Propidium; D013936:Thymidine; D014343:Trypan Blue; D014966:Xanthenes; D000099180:Interleukin-24; C005843:resazurin