Doublecortin-like kinase 1 activates Hippo pathway to promote migration, invasion and proliferation of pancreatic cancer cells / 中华肿瘤杂志

Objective: To explore the mechanism of Doublecortin-like kinase 1 (DCLK1) in promoting cell migration, invasion and proliferation in pancreatic cancer. Methods: The correlation between DCLK1 and Hippo pathway was analyzed using TCGA and GTEx databases and confirmed by fluorescence staining of pancreatic cancer tissue microarrays. At the cellular level, immunofluorescence staining of cell crawls and western blot assays were performed to clarify whether DCLK1 regulates yes associated protein1 (YAP1), a downstream effector of the Hippo pathway. Reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) was used to analyze the expressions of YAP1 binding transcription factor TEA-DNA binding proteins (TEAD) and downstream malignant behavior-promoting molecules CYR61, EDN1, AREG, and CTGF. Transwell test of the DCLK1-overexpressing cells treated with the Hippo pathway inhibitor Verteporfin was used to examine whether the malignant behavior-promoting ability was blocked. Analysis of changes in the proliferation index of experimental cells used real-time label-free cells. Results: TCGA combined with GTEx data analysis showed that the expressions of DCLK1 and YAP1 molecules in pancreatic cancer tissues were significantly higher than those in adjacent tissues (P<0.05). Moreover, DCLK1was positively correlated with the expressions of many effectors in the Hippo pathway, including LATS1 (r=0.53, P<0.001), LATS2 (r=0.34, P<0.001), MOB1B (r=0.40, P<0.001). In addition, the tissue microarray of pancreatic cancer patients was stained with multicolor fluorescence, indicated that the high expression of DCLK1 in pancreatic cancer patients was accompanied by the up-regulated expression of YAP1. The expression of DCLK1 in pancreatic cancer cell lines was analyzed by the CCLE database. The results showed that the expression of DCLK1 in AsPC-1 and PANC-1 cells was low. Thus, we overexpressed DCLK1 in AsPC-1 and PANC-1 cell lines and found that DCLK1 overexpression in pancreatic cancer cell lines promoted YAP1 expression and accessible to the nucleus. In addition, DCLK1 up-regulated the expression of YAP1 binding transcription factor TEAD and increased the mRNA expression levels of downstream malignant behavior-promoting molecules. Finally, Verteporfin, an inhibitor of the Hippo pathway, could antagonize the cell's malignant behavior-promoting ability mediated by high expression of DCLK1. We found that the number of migrated cells with DCLK1 overexpressing AsPC-1 group was 68.33±7.09, which was significantly higher than 22.00±4.58 of DCLK1 overexpressing cells treated with Verteporfin (P<0.05). Similarly, the migration number of PANC-1 cells overexpressing DCLK1 was 65.66±8.73, which was significantly higher than 37.00±6.00 of the control group and 32.33±9.61 of Hippo pathway inhibitor-treated group (P<0.05). Meanwhile, the number of invasive cells in the DCLK1-overexpressed group was significantly higher than that in the DCLK1 wild-type group cells, while the Verteporfin-treated DCLK1-overexpressed cells showed a significant decrease. In addition, we monitored the cell proliferation index using the real-time cellular analysis (RTCA) assay, and the proliferation index of DCLK1-overexpressed AsPC-1 cells was 0.66±0.04, which was significantly higher than 0.38±0.01 of DCLK1 wild-type AsPC-1 cells (P<0.05) as well as 0.05±0.03 of DCLK1-overexpressed AsPC1 cells treated with Verteporfin (P<0.05). PANC-1 cells showed the same pattern, with a proliferation index of 0.77±0.04 for DCLK1-overexpressed PANC-1 cells, significantly higher than DCLK1-overexpressed PANC1 cells after Verteporfin treatment (0.14±0.05, P<0.05). Conclusion: The expression of DCLK1 is remarkably associated with the Hippo pathway, it promotes the migration, invasion, and proliferation of pancreatic cancer cells by activating the Hippo pathway.

Mechanism of DCLK1 transcriptional regulation in HCC / 中国临床药理学与治疗学

AIM: To investigate the molecular mechanism through which DKK1 is transcriptionally regulated in HCC (hepatocellular carcinoma) cells. METHODS: Real time PCR was used to explore whether EGFR was involved in regulating DCLK1 mRNA expression in HCC cells; Western blot assay was used to examine whether EGFR-mediated the up-regulation of DCLK1 protein in HCC cells; Immunohistochemical (IHC) analyses were used to examine the protein expression of EGFR and DCLK1 in 39 human HCC tumor specimens. RESULTS: EGF promoted the expression of DCLK1 mRNA and protein in HepG2 and Huh-7 cells (P<0.05, P<0.01), while knockdown of EGFR with two specific siRNA could reverse EGF-induced the up-regulation of DCLK1 mRNA and protein (P<0.01). IHC analyses revealed that the amount of EGFR correlated significantly with that of DCLK1 (r=0.669 6). CONCLUSION: EGFR promoted DCLK1 transcription in HCC.

Functional characteristic research progress of DCLK1 as a potential biomarker in cancer stem cells for gastrointestinal onalignancies / 实用肿瘤学杂志

The discovery and application of cancer stem cell markers have very important significance on tumor treatment and prevention.DCLK1 is discovered only in the cancer stem cell marker but not nomal stem cells for the first time.Some studies have shown that DCLK1 expression was detectded in gastrointestinal cancer,esoph-ageal cancer,bile duct carcinoma and glioma.The expression of DCLK1 in tumor is closely related to tumor devel-opment,progression,and recurrenceand migration.Although DCLK1 remain to be known as cancer stem cell mark-er,it provides a new developing prospectives for tumor targeting specific treatment.