CRISPR-mediated knockout of VEGFR2/KDR inhibits cell growth in a squamous thyroid cancer cell line

Squamous and anaplastic thyroid cancers are the most aggressive and life‐threatening cancer types in humans, with the involvement of lymph nodes in 59% of cases and distant metastases in 26% of cases of all thyroid cancers. The median survival of squamous thyroid cancer patients is < 8 months and therefore is of high clinical concern. Here, we show that both VEGFC and VEGFR2/KDR are overexpressed in thyroid cancers, indicating that VEGF/VEGFR signaling plays a carcinogenic role in thyroid cancer development. Using CRISPR/Cas9, we established a KDR knockout (KO) SW579 squamous thyroid cancer cell line that exhibited dramatically decreased colony formation and invasion abilities (30% and 60% reduction, respectively) when compared to scrambled control cells. To validate the potential of KDR as a therapeutic target for thyroid cancers, we used the KDR RTK inhibitor sunitinib. Protein analysis and live/dead assay were performed to demonstrate that sunitinib significantly inhibited cell growth signal transduction and induced cell apoptosis of SW579 cells. These results suggest that selective targeting of KDR may have potential for development into novel anti‐cancer therapies to suppress VEGF/VEGFR‐mediated cancer development in patients with clinical advanced thyroid cancer.

Evaluation of epigenetic inactivation of vascular endothelial growth factor receptors in head and neck squamous cell carcinoma

The aim of this study was to determine the methylation status of the genes encoding the vascular endothelial growth factor receptors and to evaluate the usefulness of VEGFR methylation as a prognostic indicator in head and neck squamous cell carcinoma. VEGFR messenger RNA expression and promoter methylation were examined in a panel of cell lines via quantitative reverse transcription and methylation-specific polymerase chain reaction, respectively. Promoter methylation was compared with clinical characteristics in 128 head and neck squamous cell carcinoma samples. The normalized methylation values for the VEGFR1, VEGFR2 and VEGFR3 promoters tended to be higher in the tumour cell lines than in normal tonsil samples, whereas amounts of VEGFR1, VEGFR2 and VEGFR3 messenger RNA were significantly higher. Methylation of the VEGFR1 promoter (p = 0.003; 66/128 head and neck squamous cell carcinoma samples, 52%) and VEGFR3 promoter (p = 0.043; 53/128 head and neck squamous cell carcinoma samples, 41%) significantly correlated with recurrence, whereas methylation of the VEGFR2 promoter significantly correlated with lymph node metastasis (p = 0.046; 47/128 head and neck squamous cell carcinoma samples, 37%). Concurrent methylation of the VEGFR1 and VEGFR3 promoters significantly correlated with reduced disease-free survival (log-rank test, p = 0.009). In a multivariate logistic regression analysis, methylation of the VEGFR1, VEGFR3 and both the VEGFR1 and VEGFR3 promoters independently predicted recurrence (odds ratios and 95% confidence intervals: 3.19, 1.51-6.75 (p = 0.002); 2.24, 1.06-4.76 (p = 0.035); and 2.56, 1.09-6.05 (p = 0.032), respectively). Methylation of the VEGFR promoters predicts poor prognosis in head and neck squamous cell carcinoma patients.

Synthesis, Biological Evaluation and Docking Studies of Sorafenib Derivatives N-(3-fluoro-4-(pyridin-4-yloxy)phenyl)-4(5)-phenylpicolinamides

BACKGROUND

Sorafenib is an important VEGFR2/KDR inhibitor which is widely used for the treatment of cancer.

OBJECTIVE

In this paper, two series of sorafenib analogues N-(3-fluoro-4-(pyridin-4-yloxy)phenyl)-4- phenylpicolinamides(13a-k) and N-(3-fluoro-4-(pyridin-4-yloxy)phenyl)-5-phenylpicolinamides (14a-k) were designed and synthesized.

METHODS

Their structures were confirmed by various analytical methods, such as 1 H and 13 C NMR, m.p., MS, HRMS. All of them were evaluated for IC50 values against three cancer cell lines (A549, PC-3 and MCF-7).

RESULTS

Eleven of the synthesized compounds showed moderate to excellent cytotoxicity activity against different cancer cells, whose potency from single-digit µM to nanomolar range. And five of them were equal to more potent than sorafenib against one or more cell lines. The most promising compound 14c showed excellent antitumor activities against PC-3 and MCF-7 cell lines with IC50 values of 2.62±1.07 µM and 1.14±0.92 µM, which were 1.15 to 2.75-fold more active than sorafenib (3.03±1.01 µM, 3.14±1.65 µM), respectively.

CONCLUSION

Structure-activity relationships (SARs) and docking studies indicated that the replacement of diarylurea of sorafenib with phenylpicolinamide moiety benefited to the activity. The position of aryl group and the substituents of aryl group had a great influence on antitumor activity and selectivity. The aryl groups with the substitute of alkyl groups (-CH3), halogen atoms (-F,Cl) were favorable to the cytotoxicity. However, this series of compounds showed moderate activity against VEGFR2/KDR kinase. Mechanism of target compounds was not quite clear and further study will be carried out to identify the possible target.

Synthesis, activity and docking studies of phenylpyrimidine-carboxamide Sorafenib derivatives

Two series of Sorafenib derivatives bearing phenylpyrimidine-carboxamide moiety (16a-g and 17a-p) were designed, synthesized and evaluated for the IC₅₀ values against three cancer cell lines (A549, MCF-7 and PC-3). Two selected compounds (17f and 17n) were further evaluated for the activity against VEGFR2/KDR kinase. More than half of the synthesized compounds showed moderate to excellent activity against three cancer cell lines. Compound 17f showed equal activity to Sorafenib against MCF-7 cell line, with the IC₅₀ values of 6.35±0.43μM. Meanwhile, compound 17n revealed more active than Sorafenib against A549 cell line, with the IC₅₀ values of 3.39±0.37μM. Structure-activity relationships (SARs) and docking studies indicated that the second series (17a-p) showed more active than the first series (16a-g). What's more, the introduction of fluoro atom to the phenoxy part played no significant impact on activity. In addition, the presence of electron-donating on aryl group was benefit for the activity.