Objective: To analyze the
protein expression differences of lacrimal gland
adenoid cystic carcinoma (LACC) with high-grade transformation (HGT). Methods: Experimental study. A total of 8
paraffin tissue samples were collected in Tianjin Medical University Eye Hospital from December 2012 to January 2019. According to pathological examination, the samples were divided into the LACC group and the LACC-HGT group, with 4 cases in each group. The LACC group included 2 male samples and 2 female samples, with an average age of 53 years. The LACC-HGT group included 2 male samples and 2 female samples, with an average age of 44 years. Primary cells were cultured from fresh
tumor tissue. Isobaric tags for relative and absolute quantification techniques were used to screen the differentially expressed
proteins between the two groups, and bioinformatics analysis was conducted for the differentially expressed
proteins. Microarray was used to screen differentially expressed mRNAs between LACC and LACC-HGT primary cells. The mass spectrum data were intersected with
mRNA microarray data, and quantitative real-time (qRT) PCR was performed to verify the results. Proteomics and microarray data were compared using the independent sample t test. The qRT-PCR data were compared pairwise by one-way analysis of variance. Results: A total of 105 HGT-related differential
proteins were detected in this study, including 50 up-regulated
proteins and 55 down-regulated
proteins. The significantly up-regulated
proteins included
hemoglobin subunit beta,
hemoglobin subunit alpha 1, and
collagen type Ⅵ alpha 2 chain; the significantly down-regulated
proteins included Cereblon,
adenosylhomocysteinase like 2, and
ribosomal protein L39 pseudogene 5. Gene ontology analysis results showed that the LACC-HGT differential
proteins were mainly located in the cytoplasm, vesicle cavity, and extracellular matrix, had organic
acid binding and molecular carrier activity, and participated in the regulation of extracellular matrix composition, immunity,
inflammation, apoptosis, and other biological processes. Pathway analysis showed that the LACC-HGT differential
proteins were mainly involved in signal pathways such as
mitogen-activated protein kinase signal pathway and extracellular matrix
proteoglycans and
glycan metabolism signal pathway.
Protein complex prediction analysis screened out 4 up-regulated
protein complexes and 1 down-regulated
protein complex. There were 15 LACC-HGT differential
proteins that overlapped with
mRNA chip differential genes, of which 6 were
tumor-related
proteins including
collagen type XIV alpha 1 chain (COL14A1), EMAP like 4 (EML4),
inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4), NDRG family member 2 (NDRG2), osteoglycin (OGN) an
Ras homolog family member C (RhoC). The main function was the movement and migration of
tumor cells. The qRT-PCR results showed that the relative expression levels of COL14A1, EML4, ITIH4, NDRG2, OGN, and RhoC in primary LACC-1, LACC-2, LACC-HGT-1, and LACC-HGT-2 cells were significantly different (F=1 675.98, 38.53, 27.37, 16.47, 13.38, 25.22, all P<0.01). For example, the relative expression of COL14A1 in primary LACC-HGT-1 (16.09±0.51) and LACC-HGT-2 (9.96±0.34) cells was significantly higher than that in primary LACC-1 (1.00±0.13) and LACC-2 (0.67±0.08) cells (all P<0.05). Conclusion: There are differentially expressed
proteins between LACC-HGT and LACC, among which COL14A1, EML4, ITIH4, NDRG2, OGN, and RhoC may play an important role in LACC-HGT and can be used as potential targets of LACC-HGT in further study. (Chin J Ophthalmol, 2021, 57: 531-539).