Figures at a glance

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FIGURE 1

Figure 1: PKIB is increased in BC tissues. (A) PKIB expression in different cancers compared with normal tissues in TCGA and GTEx datasets. (B) PKIB expression in different cancers compared with paired normal tissues in TCGA datasets. (C) PKIB expression in BC compared with normal tissues in BC datasets from TCGA database. (D) PKIB expression in BC compared with paired normal tissues in BC datasets from TCGA database. (E) ROC curves for assessing the specificity and sensitivity of PKIB to differentiate between BC and normal tissues. (F) Protein expression of PKIB in BC and normal tissue in ULCAN datasets. (G) Protein expression of PKIB detected using IHC in HPA database. *p<0.05, **p<0.01, and ***p<0.001.

FIGURE 2

Figure 2: PKIB mRNA expression is associated with clinicopathological characteristics. mRNA expression level of PKIB in breast cancer patients with different characteristics, including (A) Anatomic neoplasm subdivisions, (B) pathological T stage, (C) pathologic M stage, (D) sex, (E) race, (F) age, (G) pathological N stage, (H) ER status pathological stage, (I) PR status histologic grade, (J) HER2 status, (K) Menopause status, (L) disease specific survival (DSS). *p<0.05, **p<0.01, and ***p<0.001.

FIGURE 3

Figure 3: PKIB protein level is associated with clinicopathological characteristics. Protein expression level of PKIB in BC patients with different characteristics, including (A) sample types, (B) cancer stage, (C) race, (D) age, (E) major subclass, (G) tumor histology, and (G-I) PKIB expression in samples with WNT pathway, chromatin modifiers, and SWI-SNF complexes status. *p<0.05, **p<0.01, and ***p<0.001.

FIGURE 4

Figure 4: Low expression of PKIB is positively associated with poor prognosis. Kaplan–Meier analyses of the correlations between PKIB and (A) overall survival, (B) disease specific survival, and (C) progression free interval. Kaplan–Meier analyses of the correlations between PKIB and overall survival in different subgroups, including patients of (D) less than 60 years old, (E) T3 and T4 stages, (F) N1 stage, (G) M1 stage, (H) stage III and IV, (I) race, and (J-L) ER, PR, HER2 status.

FIGURE 5

Figure 5: Functional enrichment analysis of PKIB-related differentially expressed genes (DEGs). (A) Volcano plot of DEGs. Blue and yellow dots indicate the significantly down-regulated and up-regulated DEGs, respectively. (B, C) Network diagram of GO and KEGG analysis of DEGs. (D) Mountain map of GSEA analysis (GSEA) of DEGs. (E) Protein-protein interaction network of PKIB and other related genes in the STRING database. (E) Correlation between PKIB expression and different functional states in BC based on CancerSEA database. *p<0.05, **p<0.01, and ***p<0.001.

FIGURE 6

Figure 6: PKIB expression is correlated with immune infiltration level in breast cancer (BC). (A) Correlation between PKIB expression and different immune cells. The size of dots indicates the absolute Spearman’s correlation coefficient values. (B) Correlation between GREB1 expression and different immune cells. The size of dots indicates the absolute Spearman’s correlation coefficient values. (C) Heatmap of correlation between PKIB expression and immune-checkpoint-related gene expression. (D) Heatmap of correlation between GREB1 expression and immune-checkpoint-related gene expression. (E) Correlations between PKIB expression and GREB1 expression. (F) Immunohistochemical analysis of GREB1 and PDCD1LG2 in paired BC tissues. *p<0.05, **p<0.01, and ***p<0.001.

FIGURE 7

Figure 7: Different expression levels of PKIB protein in breast cancer

FIGURE 8

Figure 8: PKIB suppression inhibits the cell growth of breast cancer (BC) cells. (A) Western blots analysis of PKIB expression in BC tissues and paired normal tissues from BC patients. (B) qRT-PCR detected the mRNA level of PKIB in BC tissues and paired normal tissues from BC patients. (C) The mRNA expression of PKIB was determined in MCF-10A and BC cell lines. (D) The protein expression of PKIB was determined in MCF-10A and BC cell lines. (E) Western blots analysis of PKIB expression in BT549 and MDA-MB-231 cells after transfection of shRNAs. (F) qRT-PCR detected the mRNA level of PKIB in BT549 and MDA-MB-231 cells after transfection of Ctrl and sh-PKIB-2. (G) CCK-8 assays were performed to detect the proliferative capacity of BT549 and MDA-MB-231 cells with PKIB knockdown. (H) Colony formation assays of BT549 and MDA-MB-231 cells after inhibition of PKIB. Representative images (left panel) and counts (right panel) of colony formation cells are shown. *p<0.05, **p<0.01, and ***p<0.001.

FIGURE 9

Figure 9: Inhibiting expression of PKIB suppresses BC cell migration, and invasion in vitro and tumor growth and metastasis in vivo. (A) Transwell migration assays were conducted to compare the migratory abilities of BT549 and MDA-MB-231 cells after PKIB knockdown. (B) Transwell invasion assays were conducted to compare the invasive abilities of BT549 and MDA-MB-231 cells after PKIB knockdown. (C) Left panel, representative image of the xenograft tumors dissected from Ctrl and sh-PKIB groups at the endpoint of the experiments (day 14). Right panel, the tumor volume and weight were measured. *P<0.0001. (D) In vivo bioluminescence imaging system captures metastasis images.