Immunohistochemical analysis on potential new molecular targets for esophageal cancer

CCR7 in esophageal squamous cell carcinoma: an identification from single-cell and bulk transcriptome sequencing

BACKGROUND

Considering the involvement of CC-chemokine receptor type 7 (CCR7) in diverse tumors, the purpose of our current study is to reveal the specific mechanisms of CCR7 in esophageal squamous cell carcinoma (ESCC).

METHODS

We processed single-cell RNA sequencing data based on the Gene Expression Omnibus (GEO) database and utilizing Seurat software, and performed filtering and annotation to obtain different cell types. Genes related to gene ontology biological process and Hallmark were collected, and the enrichment of genes of interested in both single cell and TCGA-ESCA was quantified. Besides, genes related to CCR7 and KRAS signaling up were uploaded to construct the protein-protein interaction network. A series of cellular assays were incorporated to test the effects of CCR7 in ESCC cells.

RESULTS

28,281 cells were categorized into 4 non-immune cell classes (epithelial cells, smooth muscle cells, fibroblasts, endothelial cells) and 6 immune cell classes (mast cells, plasma B cells, B cells, neutrophils, macrophages, NK/T cells). CCR7 evidently expressed higher in epithelial cells of ESCA and was positively correlated with KRAS signaling up, inflammatory response and TNFA signaling via NFKB, with the most significant correlation witnessed between CCR7 and KRAS signaling up. Meanwhile, the positive correlation between KRAS signaling up and positive regulation of epithelial cell migration was observed. 12 common genes were related to both KRAS signaling up and positive regulation of epithelial cell migration, 3 of which (SOX9, FLT4 and HDAC9) were higher-expressed in M1 group of TCGA-ESCA. Besides, CCR7 as well as its ligands CCL19 and CCL21 was shown to express higher in ESCC cells, where increased level of immune response-related cytokines was seen. CCR7 knockdown diminished migration and proliferation as well as Macrophage M2 polarization.

CONCLUSION

CCR7 was highly-expressed in ESCC and positively correlated with KRAS signaling up, which may contribute to the migration of ESCC cells.

Two Birds, One Stone: Double Hits on Tumor Growth and Lymphangiogenesis by Targeting Vascular Endothelial Growth Factor Receptor 3

Vascular endothelial growth factor receptor 3 (VEGFR3) has been known for its involvement in tumor-associated lymphangiogenesis and lymphatic metastasis. The VEGFR3 signaling is stimulated by its main cognate ligand, vascular endothelial growth factor C (VEGF-C), which in turn promotes tumor progression. Activation of VEGF-C/VEGFR3 signaling in lymphatic endothelial cells (LECs) was shown to enhance the proliferation of LECs and the formation of lymphatic vessels, leading to increased lymphatic metastasis of tumor cells. In the past decade, the expression and pathological roles of VEGFR3 in tumor cells have been described. Moreover, the VEGF-C/VEGFR3 axis has been implicated in regulating immune tolerance and suppression. Therefore, the inhibition of the VEGF-C/VEGFR3 axis has emerged as an important therapeutic strategy for the treatment of cancer. In this review, we discuss the current findings related to VEGF-C/VEGFR3 signaling in cancer progression and recent advances in the development of therapeutic drugs targeting VEGF-C/VEGFR3.

Concept of histone deacetylases in cancer: Reflections on esophageal carcinogenesis and treatment

Esophageal cancer (EC) presents a high mortality rate, mainly due to its aggressive nature. Squamous cell carcinoma is the most common histological type worldwide, though, a continuous increase in esophageal adenocarcinomas has been noted in the past decades. Common risk factors associated with EC include smoking, alcohol consumption, gastroesophageal reflux disease, Barrett's esophagus and obesity. In an effort to overcome chemotherapy resistance in oncology, it was discovered that histone acetylation/deacetylation equilibrium is altered in carcinogenesis, leading to changes in chromatin structure and altering expression of genes important in the cell cycle, differentiation and apoptosis. Based on this knowledge, histone acetylation was addressed as a potential novel chemotherapy drug target to repress cancer cell proliferation. There are four classes of histone deacetylases (HDACs) inhibitors with a variety of different mechanisms of actions that render them possible anti-cancer drugs. They arrest the cell cycle, inhibit differentiation and angiogenesis and induce apoptosis. They do not necessarily act on histone proteins, since they can also exert indirect anti-cancer effects, by modifying various cellular proteins. In addition, HDACs have also been associated with increased chemotherapy resistance. Based on the literature, HDACs have been associated with EC, with surveys revealing that increased expression of certain HDACs correlates with advanced TNM stages, tumor grade, metastatic potential and decreased 5-year overall and disease-free survival. The aim of this survey is to elucidate the molecular identity and mechanism of action of HDAC inhibitors as well as verify their potential utility as anti-cancer agents in esophageal cancer.

The role of HGF/MET and FGF/FGFR in fibroblast-derived growth stimulation and lapatinib-resistance of esophageal squamous cell carcinoma

BACKGROUND

Although advanced esophageal squamous-cell carcinoma (ESCC) is treated using a multidisciplinary approach, outcomes remain unsatisfactory. The microenvironment of cancer cells has recently been shown to strongly influence the biologic properties of malignancies. We explored the effect of supernatant from esophageal fibroblasts on the cell growth and chemo-resistance of ESCC cell lines.

METHODS

We used 22 ESCC cell lines, isolated primary human esophageal fibroblasts and immortalized fibroblasts. We first examined cell proliferation induced by fibroblast supernatant. The effect of supernatant was evaluated to determine whether paracrine signaling induced by fibroblasts can influence the proliferation of cancer cells. Next, we examined the effects of adding growth factors HGF, FGF1, FGF7, and FGF10, to the culture medium of cancer cells. These growth factors are assumed to be present in the culture supernatants of fibroblasts and may exert a paracrine effect on the proliferation of cancer cells. We also examined the intrinsic role of HGF/MET and FGFs/FGFR in ESCC proliferation. In addition, we examined the inhibitory effect of lapatinib on ESCC cell lines and studied whether the fibroblast supernatants affect the inhibitory effect of lapatinib on ESCC cell proliferation. Finally, we tested whether the FGFR inhibitor PD-173074 could eliminate the rescue effect against lapatinib that was induced by fibroblast supernatants.

RESULTS

The addition of fibroblast supernatant induces cell proliferation in the majority of cell lines tested. The results of experiments to evaluate the effects of adding growth factors and kinase inhibitors suggests that the stimulating effect of fibroblasts was attributable in part to HGF/MET or FGF/FGFR. The results also indicate diversity in the degree of dependence on HGF/MET and FGF/FGFR among the cell lines. Though lapanitib at 1 μM inhibits cell proliferation by more than 50% in the majority of the ESCC cell lines, fibroblast supernatant can rescue the growth inhibition of ESCC cells. However, the rescue effect is abrogated by co-treatment with FGFR inhibitor.

CONCLUSION

These results demonstrate that cell growth of ESCC depends on diverse receptor tyrosine kinase signaling, in both cell-autonomous and cell-non-autonomous manners. The combined inhibition of these signals may hold promise for the treatment of ESCC.