Dclk1, a tumor stem cell marker, regulates pro-survival signaling and self-renewal of intestinal tumor cells

Abstract

BackgroundMore than 80% of intestinal neoplasia is associated with the adenomatous polyposis coli (APC) mutation. Doublecortin-like kinase 1 (Dclk1), a kinase protein, is overexpressed in colorectal cancer and specifically marks tumor stem cells (TSCs) that self-renew and increased the tumor progeny in Apc Min/+ mice. However, the role of Dclk1 expression and its contribution to regulating pro-survival signaling for tumor progression in Apc mutant cancer is poorly understood.MethodsWe analyzed DCLK1 and pro-survival signaling gene expression datasets of 329 specimens from TCGA Colon Adenocarcinoma Cancer Data. The network of DCLK1 and pro-survival signaling was analyzed utilizing the GeneMANIA database. We examined the expression levels of Dclk1 and other stem cell-associated markers, pro-survival signaling pathways, cell self-renewal in the isolated intestinal epithelial cells of Apc Min/+mice with high-grade dysplasia and adenocarcinoma. To determine the functional role of Dclk1 for tumor progression, we knocked down Dclk1 and determined the pro-survival signaling pathways and stemness. We used siRNA technology to gene silence pro-survival signaling in colon cancer cells in vitro. We utilized FACS, IHC, western blot, RT-PCR, and clonogenic (self-renewal) assays.ResultsWe found a correlation between DCLK1 and pro-survival signaling expression. The expression of Dclk1 and stem cell-associated markers Lgr5, Bmi1, and Musashi1 were significantly higher in the intestinal epithelial cells of Apc Min/+mice than in wild-type controls. Intestinal epithelial cells of Apc Min/+mice showed increased expression of pro-survival signaling, pluripotency and self-renewal ability. Furthermore, the enteroids formed from the intestinal Dclk1+ cells of Apc Min/+mice display higher pluripotency and pro-survival signaling. Dclk1 knockdown in Apc Min/+ mice attenuates intestinal adenomas and adenocarcinoma, and decreases pro-survival signaling and self-renewal. Knocking down RELA and NOTCH1 pro-survival signaling and DCLK1 in HT29 and DLD1 colon cancer cells in vitro reduced the tumor cells’ ability to self-renew and survive.ConclusionOur results indicate that Dclk1 is essential in advancing intestinal tumorigenesis. Knocking down Dclk1 decreases tumor stemness and progression and is thus predicted to regulate pro-survival signaling and tumor cell pluripotency. This study provides a strong rationale to target Dclk1 as a treatment strategy for colorectal cancer.Electronic supplementary materialThe online version of this article (doi:10.1186/s12943-017-0594-y) contains supplementary material, which is available to authorized users.

Retracted: DCLK1 promotes epithelial‐mesenchymal transition via the PI3K/Akt/NF‐κB pathway in colorectal cancer

“…Double cortin‐like kinase 1 (DCLK1, formerly known as DCAMKL1), a member of the protein kinase superfamily and the double cortin family, was initially identified as a critical regulator of neurogenesis and neuronal migration . Recently, DCLK1 has been identified as a tumor stem cell marker in CRC, pancreatic cancer and other cancers . DCLK1 protein is highly expressed in several types of cancers, including CRC, pancreatic cancer, hepatocellular carcinoma (HCC), and renal clear cell carcinoma (RCC) .…”

Inhibition of LEF1-Mediated DCLK1 by Niclosamide Attenuates Colorectal Cancer Stemness

“…Currently, accumulating evidence suggests that long-lived DCLK1þ tuft cells may be responsible for colorectal cancer development by participating as tumor-initiating populations with persistent Wnt activation (8). DCLK1 was determined to be responsible for cancer progression via the enhancement of survival (44), self-renewal (44), and epithelial-mesenchymal transition (45,46). Moreover, clinical studies in patients with colorectal cancer demonstrated that DCLK1 was expressed in low-grade adenomas, and its levels increased with worsening severity of dysplasia (47).…”

DCLK1 Expression in Colorectal Polyps Increases with the Severity of Dysplasia

“…In a study on CRC metastasis, Gao et al reported that DCLK1 expression was significantly increased in primary CRC and in lymphatic metastases compared with normal colorectal specimens, and moreover, DCLK1 mRNA levels in CRC were significantly correlated with lymph node metastasis and TNM stage (10). DCLK1 expression has also been strongly associated with EMT (18,20). Although a number of genetic studies on DCLK1 have been reported, only few reports have investigated the behavior and distribution of DCLK1 expression in human CRC tissues.…”