Graphene
Oxide-Facilitated Comprehensive Analysis of Cellular Nucleic Acid
Binding Proteins for Lung Cancer
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Abstract
Nucleic
acid binding proteins (NABPs) mediate a broad range of essential cellular
functions. However, it is very challenging to comprehensively extract
whole cellular NABPs due to the lack of approaches with high efficiency.
To this end, carbon nanomaterials, including graphene oxide (GO),
carboxylated graphene (cG), and carboxylated carbon nanotube (cCNT),
were utilized to extract cellular NABPs in this study through a new
strategy. Our data demonstrated that GO, cG, and cCNT could extract
nearly 100% cellular DNA in vitro. Conversely, their RNA extraction
efficiencies were 60, 50, and 29%, respectively, partially explaining
why GO has the highest NABPs yield compared to cG and cCNT. We further
found that ionic bond mediated by cations between RNA and functional
groups of nanomaterials facilitated RNA absorption on nanomaterials.
About 2400 proteins were successfully identified from GO-enriched
NABPs sample, and 88% of annotated NABPs were enriched at least 2
times compared to cell lysate, indicating the high selectivity of
our strategy. The developed method was further applied to compare
the NABPs in two lung cancer cell lines with different tumor progression
abilities. According to label-free quantification results, 118 differentially
expressed NABPs were discovered and 6 candidate NABPs, including ACAA2,
GTF2I, VIM, SAMHD1, LYAR, and IGF2BP1, were successfully validated
by immunoassay. The level of SAMHD1 in the serum of lung cancer patients
was measured, which significantly increased upon cancer progression.
Our results collectively demonstrated that GO is an ideal nanomaterial
for NABPs selective extraction, which could be broadly used in varied
physiological and pathophysiological settings