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University of Colorado Denver General Hematology Program Research


Gamini Siriwardana

Senior Research Associate

Gamini received his BS from the University of Sri Lanka, MS from Colorado State University and PhD from the University of Hawaii.  He was a Post-Doctoral Fellow at both Colorado State University and the University of Wyoming at Laramie.  He began working as a Professional Research Assistant at the University of Colorado and between 1991 and late 2004 he worked in the Department of General Internal Medicine, the Division of Hematology, Renal and Pediatrics.  He returned to the Seligman Lab in 2004. 




The iron (Fe) chelator desferrioxamine (DFO) has been found to be effective as a treatment for neuroblastoma which is a childhood cancer. Iron is a co-factor needed for the enzyme ribonucleotide reductase to convert ribose to deoxyribose during DNA syntheses. Hence a block at late G1 phase of the cell cycle is expected in cells undergoing mitosis. However another block at early G1 has been observed with a variety of the treatment with DFO in cancer cell lines. This effect has been observed with many other iron chelators implying that this block is related to Fe deprivation and not due to DFO through some other mechanism. No explanation for this effect has been provided thus far in spite of many research publications on this subject.


Gamini’s project in General Hematology primarily involves pinpointing the cause of early G1 cell cycle arrest using neuroblastoma cell lines as a model. The work is primarily based on using molecular biology tools such as specific inhibitors of proteins, mutant plasmids, small interfering RNA (siRNA), techniques involving signal transduction, western analyses, cell cycle analyses, PCR procedures.


Publications have been made based on this research, the most recent being on better differentiation of the two arrest points by iron chelation and the molecular events involved with the two distinct blocks.