Overexpression of DCLK1-AL Increases Tumor Cell Invasion, Drug Resistance, and KRAS Activation and Can Be Targeted to Inhibit Tumorigenesis in Pancreatic Cancer

Dongfeng Qu; Nathaniel Weygant; Jiannan Yao; Parthasarathy Chandrakesan; William L Berry; Randal May; Kamille Pitts; Sanam Husain; Stan Lightfoot; Min Li; Timothy C Wang; Guangyu An; Cynthia Clendenin; Ben Z Stanger; Courtney W Houchen

doi:10.1155/2019/6402925

Overexpression of DCLK1-AL Increases Tumor Cell Invasion, Drug Resistance, and KRAS Activation and Can Be Targeted to Inhibit Tumorigenesis in Pancreatic Cancer

J Oncol. 2019 Aug 5:2019:6402925. doi: 10.1155/2019/6402925. eCollection 2019.

Authors

Dongfeng Qu^{1

2

3}, Nathaniel Weygant¹, Jiannan Yao⁴, Parthasarathy Chandrakesan^{1

2

3}, William L Berry⁵, Randal May^{1

2}, Kamille Pitts¹, Sanam Husain⁶, Stan Lightfoot⁶, Min Li¹, Timothy C Wang⁷, Guangyu An⁴, Cynthia Clendenin⁸, Ben Z Stanger⁸, Courtney W Houchen^{1

2

3}

Affiliations

¹ Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
² Department of Veterans Affairs Medical Center, Oklahoma City, OK, USA.
³ Peggy and Charles Stephenson Cancer Center, Oklahoma City, OK, USA.
⁴ Department of Oncology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China.
⁵ Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
⁶ Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
⁷ Department of Digestive and Liver Diseases, Columbia University Medical Center, New York, NY, USA.
⁸ Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.

Abstract

Oncogenic KRAS mutation plays a key role in pancreatic ductal adenocarcinoma (PDAC) tumorigenesis with nearly 95% of PDAC harboring mutation-activated KRAS, which has been considered an undruggable target. Doublecortin-like kinase 1 (DCLK1) is often overexpressed in pancreatic cancer, and recent studies indicate that DCLK1+ PDAC cells can initiate pancreatic tumorigenesis. In this study, we investigate whether overexpressing DCLK1 activates RAS and promotes tumorigenesis, metastasis, and drug resistance. Human pancreatic cancer cells (AsPC-1 and MiaPaCa-2) were infected with lentivirus and selected to create stable DCLK1 isoform 2 (alpha-long, AL) overexpressing lines. The invasive potential of these cells relative to vector control was compared using Matrigel coated transwell assay. KRAS activation and interaction were determined by a pull-down assay and coimmunoprecipitation. Gemcitabine, mTOR (Everolimus), PI3K (LY-294002), and BCL-2 (ABT-199) inhibitors were used to evaluate drug resistance downstream of KRAS activation. Immunostaining of a PDAC tissue microarray was performed to detect DCLK1 alpha- and beta-long expression. Analysis of gene expression in human PDAC was performed using the TCGA PAAD dataset. The effects of targeting DCLK1 were studied using xenograft and Pdx1^CreKras^G12DTrp53^R172H/+ (KPC) mouse models. Overexpression of DCLK1-AL drives a more than 2-fold increase in invasion and drug resistance and increased the activation of KRAS. Evidence from TCGA PAAD demonstrated that human PDACs expressing high levels of DCLK1 correlate with activated PI3K/AKT/MTOR-pathway signaling suggesting greater KRAS activity. High DCLK1 expression in normal adjacent tissue of PDAC correlated with poor survival and anti-DCLK1 mAb inhibited pancreatic tumor growth in vivo in mouse models.

Abstract

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