- Analysis of mRNA expression of actin-binding proteins PFN1, CFL1, CAP1 and signaling molecules SNAI1 and RND3 in tumor tissue of patients with squamous cell carcinoma of the larynx and hypopharynx
The study of the expression level of the genes encoding ABPs (PFN1, CFL1, and CAP1) and signaling molecules (SNAI1 and RND3) showed the presence of all parameters in the tissues of SCCLH. The median values of all parameters in the tumor tissue of patients with SCCLH are presented in Table 2. The expression profile of genes encoding proteins involved in the remodeling of the actin cytoskeleton did not show statistically significant differences between groups of SCCLH patients with lymphogenous metastases (T2-4N1-2M0, n=24) and SCCLH patients without clinically detectable lymphogenous metastases (T2-4N0M0, n=29). However, there was a tendency to an increase of the expression activity of the SNAI1, CFL1 and CAP1 genes in the tumor tissue of patients with SCCLH (T2-4N1-2M0).
TABLE 2.
Expression level of mRNA of genes encoding proteins involved in cytoskeleton remodeling depending on the presence of metastases in SCCLH patients
mRNA
|
T1-4N0-2M0
n=54
|
T1-3N0M0
n = 29
|
T2-4N1-2M0
n = 25
|
Р T1-3N0M0/ T2-4N1-2M0
(U-test)
|
snai1
|
0.78(0.15;4.48)
|
0.41 (0.12;1.44)
|
3.01 (0.7;11.4)
|
0.07
|
rnd3
|
0.61(0.0;2.30)
|
0.51 (0.06;3.27)
|
1.38 (0.22;4.23)
|
0.18
|
pfn1
|
2.51(0.15;13.24)
|
2.51 (0.01;9.08)
|
1.71 (0.5;19.7)
|
0.74
|
CFL1
|
1.16(0.10;18.86)
|
0.68 (0.06;3.6)
|
2.76 (0.14;25.5)
|
0.08
|
CAP1
|
1.95(0.03;22.66)
|
2.09 (0.07;12.9)
|
9.33 (1.14;19.3)
|
0.06
|
Note: italics indicate the significance level at the trend (0.05>p<0.1); cells marked in gray contain the results of mRNA expression of genes associated with the epithelial-mesenchymal transition; p - significance of differences between groups «T1-3N0M0» and «T2-4N1-2M0»
A correlation analysis was carried out in the general group of SCCLH patients to determine the relationship between the expression activity of the EMT markers and ABPs genes. Numerous positive correlations have been identified between the studied molecular parameters in tumor tissue. The expression activity of RND3 was associated with the expression of PFN1 (r = 0.5; p≤0.05) and CFL1 (r = 0.4; p=0.047). The SNAI1 mRNA level correlated with the PFN1 mRNA level (r = 0.4; p=0.046). Сo-expression of mRNA in group of ABPs was found: CAP1-CFL1 (r = 0.6; p=0.033), CFL1-PFN1 (r = 0.7; p=0.042) and PFN1-СAP1 (r = 0.5; p =0.037).
Further the total sample of SCCLH patients was divided into groups depending on the presence of metastases in the regional lymph nodes. In the group of patients with SCCLH T1-3N0M0 the correlation analysis revealed a relationship between the mRNA levels of SNAI1-CFL1 and RND3-PFN1. In the group of patients with SCCLH T2-4N1-2M0 the SNAI1 mRNA level correlated with the CAP1 mRNA level, and RND3 correlated with CFL1 and PFN1, while the strength of the relationship between the CAP1-CFL1-PFN1 ABPs mRNA expression was stronger than in the group without metastases (Table 3).
TABLE 3.
Spearman's correlation coefficients in groups with and without metastases: expression of EMT associated and ABPs genes in tumor tissue of SCCLH patients
mRNA
|
SNAI1
|
RND3
|
PFN1
|
CFL1
|
CAP1
|
SNAI1
|
|
0.1
|
0.5
|
0.5*
|
0.2
|
RND3
|
0.3
|
|
0.4*
|
0.2
|
0.1
|
PFN1
|
0.4
|
0.7*
|
|
0.6*
|
0.4*
|
CFL1
|
0.3
|
0.6*
|
0.7*
|
|
0.5*
|
CAP1
|
0.5*
|
0.2
|
0.7*
|
0.8*
|
|
Note: * - correlations with p≤0.05; cells marked in white contain correlation coefficients for group of SCCLH patients without metastases (T1-3N0M0); cells marked in gray contain correlation coefficients for group of SCCLH patients with metastases (T2-4N1-2M0)
To assess the relationship between the expression level of SNAI1 and RND3 and the metastatic status of SCCLH patients the total group (N = 54, 100%) was divided depending on the level of expression of these genes by the median. The first group consisted of patients with a high level of expression of the SNAI1 and RND3 genes (fig. 1A), the second - with a low level of expression of these genes (fig. 1B). A low expression level of SNAI1 (0 - 1.09) was observed in 54% SCCLH patients of the total group 20% of which had lymphogenous metastases (N+) and 80% without metastases (N-). A high level of SNAI1 (2 - 76.3) was observed in 46% SCCLH patients of the total group, among whom 47% of patients had lymphogenous metastases and 53% did not.
When analyzing the dependence of the level of ABPs mRNA expression on the level of SNAI1 expression activity significant differences were not found for PFN1 and CAP1 (Fig. 2C). A high level of SNAI1 expression was accompanied by a high level of mRNA expression of PFN1.
Low expression activity of RND3 (0 - 1.1) was detected in tumor tissue in 44% SCCLH patients of the total group among whom the proportion of patients with lymphogenous metastases accounted for 18% with metastases and 82% without them (Fig. 1, A). High expression of RND3 mRNA (1.1-81.29) was observed in 56%, among which 51% of patients were with metastases and 49% without metastases (Fig. 1B). A high level of RND3 expression was accompanied by a high level of mRNA expression of PFN1, CFL1, and CAP1 (Fig. 2D). Moreover the dependence of PFN1 and CFL1 mRNA levels on the level of RND3expression was confirmed by correlation analysis, the results of which were described in Table 3.
- Quantitative analysis of actin-binding proteins PFN1, CFL1 and CAP1 circulating in the blood serum of patients with squamous cell carcinoma of the larynx and hypopharynx
The next stage of the study was to assess level of circulating ABPs in the blood serum of SCCLH patients by ELISA. Table 4 shows the median values of ABPs level in the blood serum of SCCLH patients in the general group (T1-4N0-2M0) and in groups depending on the presence of lymphogenous metastasis (T1-3N0M0, T2-4N1-2M0).
TABLE 4.
Level of ABPs in the blood serum of SCCLH patients depending on the metastatic lesion of regional lymph nodes.
ABPs
|
T1-4N0-2M0
n=54
|
T1-3N0M0
n = 29
|
T2-4N1-2M0
n = 25
|
Р (U-test)
|
PFN1, ng\ml
|
0.30(0.24;0.37)
|
0.33(0.27;0.41)
|
0.26(0.23;0.36)
|
Р =0.05
|
CFL1, ng\ml
|
0.84(0.63;1.20)
|
0.86(0.60;1.01)
|
0.78(0.65;1.28)
|
Р=0.17
|
CAP1, ng\ml
|
0.11(0,08;0.15)
|
0.08(0.06;0.15)
|
0.14(0.08;0.19)
|
Р= 0.02
|
Note: p - significance of differences between groups «T1-3N0M0» and «T2-4N1-2M0»
There was a significant decrease in the level of profilin-1 by 21% (p = 0.05) and an increase in the level of CAP1 by 75% (p = 0.02) in the blood serum of patients with clinically confirmed metastases to the regional lymphatic nodes compared with the group of patients without lymphogenous metastases. It should be noted that in spite of the fact that no significant links were revealed by correlation analysis the direction of changes in the levels of mRNA expression of PFN 1 and CAP1 in tissues was similar to the serum levels of these proteins. At the same time the expression level of CFL1 in the tumor tissue of SCCLH patients with lymphogenous metastases significantly increased (p = 0.08) while the protein level in the blood serum of these patients remained practically unchanged.
ROC analysis was carried out to estimate the possibility to use ABPs level for predicting SCCLH metastasis. ROC analysis is proposed as a simple and practical tool for assessing the ability of candidate predictive factors in a binary classification [28]. Serum PFN1 and CAP1 were the most significant classifiers (area under the curve AUC = 0.75 (95% CI: 0.06 ~ 0.45) and area under the curve AUC = 0.81 (95% CI: 0.65 ~ 0.97 respectively).