KYSE-520

TK-642 Inhibits Cell Proliferation and Induces Apoptosis of Esophageal Cancer Cells In Vitro

Src homology-2-containing protein tyrosine phosphatase 2 (SHP2) is a promising therapeutic target for cancer therapy. Pyrazolopyrazine-based TK-642 is identified as a highly potent, selective, orally bioavailable allosteric SHP2 inhibitor with favorable pharmacokinetic profiles.

The cellular thermal shift assay (CETSA) was performed to investigate the potential of TK-642 in targeting intracellular SHP2 protein. As illustrated in Fig. 1A, a significantly higher expression level of SHP2 protein was observed within the temperature range of 45-63°C in EGFR amplified KYSE-520 esophageal cancer cell lines treated with TK-642, as compared to the DMSO treatment group. This finding indicated that TK-642 could effectively bind to and enhance the thermal stability of intracellular SHP2 protein in KYSE-520 cells.

Considering the well-known oncogenic roles of SHP2 in the development of esophageal cancer, we proceeded to investigate the impact of TK-642 on cell proliferation and apoptosis of KYSE-520 cell lines, with SHP099 serving as a control. The results revealed that both compounds exhibited moderate effects on the proliferation of KYSE-520 cells. Especially, the inhibitory activity of TK-642 on the KYSE-520 cells was approximately 3-fold greater than that of SHP099 (Fig. 1B). Moreover, we also verified the anti-tumor activity of TK-642 in non-small cell lung cancer H1975 and gastric cancer HGC-27 cells (Fig. 1C). Similar to SHP099, TK-642 also induced the apoptosis of KYSE-520 cells in a concentration-dependent manner (Fig. 1D).

Fig. 1. TK-642 inhibits cell proliferation and induces apoptosis of esophageal cancer cells KYSE-520 (Tang, Kai, et al. 2024).

Cell Proliferation Was Reduced in Hsa_circ_0001615 Knockdown Cells

Recent studies have found that circular RNAs (circRNAs) play important roles in tumorigenesis. This study aimed to determine the function and potential mechanisms of hsa_circ_0001615 in esophageal cancer.

The endogenous expression of hsa_circ_0001615 was quantified in three esophageal cancer cell lines (ECA-109, TE-1, KYSE520) and normal esophageal cells (HEEC). The relative expression of hsa_circ_0001615 was higher in the three esophageal cancer cell lines than in normal esophageal cells. Moreover, it was higher in ECA-109 and KYSE520 cells than in TE-1 cells (Fig. 2A).

ECA-109 and KYSE520 cell lines were used to transfect hsa_circ_0001615 siRNA to gain a better understanding of the functions of hsa_circ_0001615. The relative expression of hsa_circ_0001615 was significantly reduced after transfection with siRNAs for 48 h (Fig. 2B). Cell proliferation was significantly impaired when hsa_circ_0001615 was knocked down in ECA-109 and KYSE520 cells, as demonstrated by MTS assays (Fig. 2C). Cloning assay was also performed to confirm the growth defect in hsa_circ_0001615 knockdown cell lines. The number of clone formation was substantially decreased when hsa_circ_0001615 was knocked down (Fig. 2D). These results indicated that reduced hsa_circ_0001615 expression decreased cell proliferation and colony formation in ECA-109 and KYSE520 cell lines.

Fig. 2. Reduced cell proliferation in hsa_circ_0001615 knockdown cells (Dai, Yukai, et al. 2024).