RNAi mediated Tiam1 gene knockdown inhibits invasion of retinoblastoma.
T lymphoma invasion and metastasis protein (Tiam1) is up-regulated in variety of cancers and its expression level is related to metastatic potential of the type of cancer. Earlier, Tiam1 was shown to be overexpressed in retinoblastoma (RB) and we hypothesized that it was involved in invasiveness of RB. This was tested by silencing Tiam1 in RB cell lines (Y79 and Weri-Rb1) using siRNA pool, targeting different regions of Tiam1 mRNA. The cDNA microarray of Tiam1 silenced cells showed gene regulations altered by Tiam1 were predominantly on the actin cytoskeleton interacting proteins, apoptotic initiators and tumorogenic potential targets. The silenced phenotype resulted in decreased growth and increased apoptosis with non-invasive characteristics. Transfection of full length and N-terminal truncated construct (C1199) clearly revealed membrane localization of Tiam1 and not in the case of C580 construct. F-actin staining showed the interaction of Tiam1 with actin in the membrane edges that leads to ruffling, and also imparts varying invasive potential to the cell. The results obtained from our study show for the first time that Tiam1 modulates the cell invasion, mediated by actin cytoskeleton remodeling in RB.
Larsen and Toubro Department of Ocular Pathology, Vision Research Foundation, Sankara Nethralaya, Chennai, India
Nithya
N
Subramanian
Saranya
S
Navaneethakrishnan
Jyotirmay
J
Biswas
Rupinder K
RK
Kanwar
Jagat R
JR
Kanwar
Subramanian
S
Krishnakumar
D008841:Actin Cytoskeleton / Q000378:metabolism; D000199:Actins / Q000235:genetics / Q000378:metabolism; D017209:Apoptosis / Q000235:genetics; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement / Q000235:genetics*; D049109:Cell Proliferation; D015972:Gene Expression Regulation, Neoplastic; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008856:Microscopy, Fluorescence; D009154:Mutation; D009361:Neoplasm Invasiveness; D020411:Oligonucleotide Array Sequence Analysis; D011485:Protein Binding; D034622:RNA Interference; D012175:Retinoblastoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000075684:T-Lymphoma Invasion and Metastasis-inducing Protein 1; D059467:Transcriptome
D000199:Actins; D020662:Guanine Nucleotide Exchange Factors; D000075684:T-Lymphoma Invasion and Metastasis-inducing Protein 1; C087334:TIAM1 protein, human