Human neutrophil peptides 1-3 as gastric cancer tissue markers measured by MALDI-imaging mass spectrometry: implications for infiltrated neutrophils as a tumor target.
OBJECTIVE
Human neutrophil peptides (HNPs) -1, -2 and -3 are significantly upregulated and were reported as biomarkers in gastric cancer (GC). However, the tissue location and function of HNPs 1-3 are still unclear in GC, and the spatial distribution of the triad needs to be disclosed. The aims of this study were to investigate the distribution and relationships among HNPs-1, -2 and -3, and assess whether infiltrated neutrophils accumulate in gastric tumor.


METHODS
In this study, paired samples (n=33) of the GC tissues and adjacent normal tissues from the same patients were obtained from surgery. Expression of HNPs 1-3 were detected by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). The distributions of the HNPs 1-3 in GC tissues were investigated. After verification of HNPs-1 by immunohistochemistry, infiltrated neutrophils were also detected. Then, an in vitro assay was used to observe the binding capacity and measure the cytotoxic effect of HNPs-1 against AGS cells.


RESULTS
Comparing to neighboring normal tissue, expressional level of HNPs 1-3 were significantly higher and their distributions overlapped in cancerous tissues of GC patients with high abundance in the lamina propria, whereas HNPs-1 was identified as the highest major peak. Moreover, HNPs-1, -2 and -3 correlated with each other. Besides, we also observed that increased infiltrated neutrophils accumulating in GC tissues, indicating that a strong positive correlation between HNPs 1-3 and infiltrated neutrophils. In addition, the further investigated demonstrated that the major peptide, HNPs-1, was statistically increased with the advance of tumor development from the early to advanced stage of GC (p< 0.05). Moreover, we also noticed that HNPs-1 with a great binding capacity to GC AGS cells in vitro can inhibit tumor cell growth.


CONCLUSIONS
Our results suggest that neutrophil secreted peptides, HNPs 1-3, increased in the GC tissues and could be used as potential biomarkers detected using MALDI-TOF MS, implying that elevated neutrophils may be used as a tumor target for tumor treatment. The binding capacity of HNPs-1 with GC cells implies that tracking molecules conjugated with HNPs-1 could be applied as a specific probe for GC diagnoses.
Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan.
Chun-Chia
CC
Cheng
Jungshan
J
Chang
Ling-Yun
LY
Chen
Ai-Sheng
AS
Ho
Ker-Jer
KJ
Huang
Shui-Cheng
SC
Lee
Fu-Der
FD
Mai
Chun-Chao
CC
Chang
D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D012016:Reference Values; D015203:Reproducibility of Results; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D023084:alpha-Defensins / Q000032:analysis* / Q000378:metabolism
D014408:Biomarkers, Tumor; D023084:alpha-Defensins; C406413:human neutrophil peptide 1; C406416:human neutrophil peptide 2; C406427:human neutrophil peptide 3