Inhibition Of Doublecortin-like Kinase 1 Research Articles

Repurposing diacerein to suppress colorectal cancer growth by inhibiting the DCLK1/STAT3 signaling pathway

Double cortin-like kinase 1 (DCLK1) exhibits high expression levels across various cancers, notably in human colorectal cancer (CRC). Diacerein, a clinically approved interleukin (IL)-1β inhibitor for osteoarthritis treatment, was evaluated for its impact on CRC proliferation and migration, alongside its underlying mechanisms, through both in vitro and in vivo analyses. The study employed MTT assay, colony formation, wound healing, transwell assays, flow cytometry, and Hoechst 33342 staining to assess cell proliferation, migration, and apoptosis. Additionally, proteome microarray assay and western blotting analyses were conducted to elucidate diacerein's specific mechanism of action. Our findings indicate that diacerein significantly inhibits DCLK1-dependent CRC growth in vitro and in vivo. Through high-throughput proteomics microarray and molecular docking studies, we identified that diacerein directly interacts with DCLK1. Mechanistically, the suppression of p-STAT3 expression following DCLK1 inhibition by diacerein or specific DCLK1 siRNA was observed. Furthermore, diacerein effectively disrupted the DCLK1/STAT3 signaling pathway and its downstream targets, including MCL-1, VEGF, and survivin, thereby inhibiting CRC progression in a mouse model, thereby inhibiting CRC progression in a mouse model.

Blocking of doublecortin-like kinase 1-regulated SARS-CoV-2 replication cycle restores cell signaling network.

Severe COVID-19 and post-acute sequelae often afflict patients with underlying co-morbidities. There is a pressing need for highly effective treatment, particularly in light of the emergence of SARS-CoV-2 variants. In a previous study, we demonstrated that DCLK1, a protein associated with cancer stem cells, is highly expressed in the lungs of COVID-19 patients and enhances viral production and hyperinflammatory responses. In this study, we report the pivotal role of DCLK1-regulated mechanisms in driving SARS-CoV-2 replication-transcription processes and pathogenic signaling. Notably, pharmacological inhibition of DCLK1 kinase during SARS-CoV-2 effectively impedes these processes and counteracts virus-induced alternations in global cell signaling. These findings hold significant potential for immediate application in treating COVID-19.

Targeting doublecortin-like kinase 1 reveals a novel strategy to circumvent chemoresistance and metastasis in ovarian cancer

Ovarian cancer (OvCa) has a dismal prognosis because of its late-stage diagnosis and the emergence of chemoresistance. Doublecortin-like kinase 1 (DCLK1) is a serine/threonine kinase known to regulate cancer cell “stemness”, epithelial-mesenchymal transition (EMT), and drug resistance. Here we show that DCLK1 is a druggable target that promotes chemoresistance and tumor progression of high-grade serous OvCa (HGSOC). Importantly, high DCLK1 expression significantly correlates with poor overall and progression-free survival in OvCa patients treated with platinum chemotherapy. DCLK1 expression was elevated in a subset of HGSOC cell lines in adherent (2D) and spheroid (3D) cultures, and the expression was further increased in cisplatin-resistant (CPR) spheroids relative to their sensitive controls. Using cisplatin-sensitive and resistant isogenic cell lines, pharmacologic inhibition (DCLK1-IN-1), and genetic manipulation, we demonstrate that DCLK1 inhibition was effective at re-sensitizing cells to cisplatin, reducing cell proliferation, migration, and invasion. Using kinase domain mutants, we demonstrate that DCLK1 kinase activity is critical for mediating CPR. The combination of cisplatin and DCLK1-IN-1 showed a synergistic cytotoxic effect against OvCa cells in 3D conditions. Targeted gene expression profiling revealed that DCLK1 inhibition in CPR OvCa spheroids significantly reduced TGFβ signaling, and EMT. We show in vivo efficacy of combined DCLK1 inhibition and cisplatin in significantly reducing tumor metastases. Our study shows that DCLK1 is a relevant target in OvCa and combined targeting of DCLK1 in combination with existing chemotherapy could be a novel therapeutic approach to overcome resistance and prevent OvCa recurrence.

Macrophage DCLK1 promotes obesity-induced cardiomyopathy via activating RIP2/TAK1 signaling pathway

Obesity increases the risk for cardiovascular diseases and induces cardiomyopathy. Chronic inflammation plays a significant role in obesity-induced cardiomyopathy and may provide new therapeutic targets for this disease. Doublecortin-like kinase 1 (DCLK1) is an important target for cancer therapy and the role of DCLK1 in obesity and cardiovascular diseases is unclear. Herein, we showed that DCLK1 was overexpressed in the cardiac tissue of obese mice and investigated the role of DCLK1 in obesity-induced cardiomyopathy. We generated DCLK1-deleted mice and showed that macrophage-specific DCLK1 knockout, rather than cardiomyocyte-specific DCLK1 knockout, prevented high-fat diet (HFD)-induced heart dysfunction, cardiac hypertrophy, and fibrosis. RNA sequencing analysis showed that DCLK1 deficiency exerted cardioprotective effects by suppressing RIP2/TAK1 activation and inflammatory responses in macrophages. Upon HFD/palmitate (PA) challenge, macrophage DCLK1 mediates RIP2/TAK1 phosphorylation and subsequent inflammatory cytokine release, which further promotes hypertrophy in cardiomyocytes and fibrogenesis in fibroblasts. Finally, a pharmacological inhibitor of DCLK1 significantly protects hearts in HFD-fed mice. Our study demonstrates a novel role and a pro-inflammatory mechanism of macrophage DCLK1 in obesity-induced cardiomyopathy and identifies DCLK1 as a new therapeutic target for the treatment of this disease.Upon HFD/PA challenge, DCLK1 induces RIP2/TAK1-mediated inflammatory response in macrophages, which subsequently promotes cardiac hypertrophy and fibrosis. Macrophage-specific DCLK1 deletion or pharmacological inhibition of DCLK1 protects hearts in HFD-fed mice.

Abstract 6073: First-in-class Doublecortin-like kinase 1 (DCLK1) inhibitor for targeting cancer stem cell in hepatocellular carcinoma

Abstract Cancer stem cells (CSCs) have been considered promising therapeutic targets for cancer therapy. These cells have self-renewal capacity and differentiation potential and contribute to multiple tumor malignancies, such as recurrence, metastasis, heterogeneity, multidrug resistance, and radiation resistance. Doublecortin-like kinase 1 (DCLK1) was recently identified as CSC marker is upregulated in several solid tumors, which distinguishes between cancer and normal stem cell. However, the role of DCLK1 in hepatocellular carcinoma (HCC) is unclear. According to the open database like TCGA, overexpression of DCLK1 is reported to be associated with poor prognosis in HCC patients. It was also observed that DCLK1 expression was significantly increased in the advanced stage of HCC. In addition, as a result of measuring the serum DCLK1 levels obtained from patients with liver cirrhosis or HCC treated at Seoul National University Hospital, it was confirmed that the expression of DCLK1 was significantly increased in patients with HCC compared to those with liver cirrhosis. It was also confirmed that DCLK1 was expressed in human HCC cell lines and that the expression levels of DCLK1 mRNA and protein were further increased in CSC rich human HCC cell lines. Moreover, cell death was increased at the cellular level when DCLK1 was blocked via inhibiting expression of CSC markers such as CD133 and EpCAM. After evaluating the effect of DCLK1 inhibition in CSC rich human HCC cells lines, it was found that spheroid formation decreased by suppressing CSCs markers including LGR5 and CD133. In addition, it was confirmed that cell migration decreased when DCLK1 was blocked. Even in the murine HCC model, it was found that the antitumor effect was showed when administered with DCLK1 inhibitor, DCLK1-IN-1, in xenograft model with CSC rich HCC cell lines. Our results support that DCLK1 can be used as a biomarker for the detection of HCC and may be a candidate for developing targeted therapeutics to eradicate HCC. Citation Format: Daseul Yoon, Seung Hee Jung, Ju Young Jang, Ji-Young Ahn, Seung Jin Jo, Donghyun Ko, Dong-kyu Kim, Su Jong Yu. First-in-class Doublecortin-like kinase 1 (DCLK1) inhibitor for targeting cancer stem cell in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6073.

Inhibition of DCLK1 with DCLK1-IN-1 Suppresses Renal Cell Carcinoma Invasion and Stemness and Promotes Cytotoxic T-Cell-Mediated Anti-Tumor Immunity.

Simple SummaryIn this study, we found that the novel small molecule kinase inhibitor DCLK1-IN-1 not only inhibited DCLK1 phosphorylation, stemness, and EMT-related properties of RCC cells but also revealed its potential as an immunotherapy agent and potential combination therapy with anti-PD1 against RCC in immune co-culture experiments.The approval of immune checkpoint inhibitors has expanded treatment options for renal cell carcinoma (RCC), but new therapies that target RCC stemness and promote anti-tumor immunity are needed. Previous findings demonstrate that doublecortin-like kinase 1 (DCLK1) regulates stemness and is associated with RCC disease progression. Herein, we demonstrate that small-molecule kinase inhibitor DCLK1-IN-1 strongly inhibits DCLK1 phosphorylation and downregulates pluripotency factors and cancer stem cell (CSC) or epithelial-mesenchymal transition (EMT)-associated markers including c-MET, c-MYC, and N-Cadherin in RCC cell lines. Functionally, DCLK1-IN-1 treatment resulted in significantly reduced colony formation, migration, and invasion. Additionally, assays using floating or Matrigel spheroid protocols demonstrated potent inhibition of stemness. An analysis of clinical populations showed that DCLK1 predicts RCC survival and that its expression is correlated with reduced CD8+ cytotoxic T-cell infiltration and increases in M2 immunosuppressive macrophage populations. The treatment of RCC cells with DCLK1-IN-1 significantly reduced the expression of immune checkpoint ligand PD-L1, and co-culture assays using peripheral blood monocytes (PBMCs) or T-cell expanded PBMCs demonstrated a significant increase in immune-mediated cytotoxicity alone or in combination with anti-PD1 therapy. Together, these findings demonstrate broad susceptibility to DCLK1 kinase inhibition in RCC using DCLK1-IN-1 and provide the first direct evidence for DCLK1-IN-1 as an immuno-oncology agent.

Structural Basis of Inhibition of DCLK1 by Ruxolitinib.

Given the functional attributes of Doublecortin-like kinase 1 (DCLK1) in tumor growth, invasion, metastasis, cell motility, and tumor stemness, it is emerging as a therapeutic target in gastrointestinal cancers. Although a series of specific or nonspecific ATP-competitive inhibitors were identified against DCLK1, different types of scaffolds that can be utilized for the development of highly selective inhibitors or structural understanding of binding specificities of the compounds remain limited. Here, we present our work to repurpose a Janus kinase 1 inhibitor, ruxolitinib as a DCLK1 inhibitor, showing micromolar binding affinity and inhibitory activity. Furthermore, to gain an insight into its interaction mode with DCLK1, a crystal structure of the ruxolitinib-complexed DCLK1 has been determined and analyzed. Ruxolitinib as a nonspecific DCLK1 inhibitor characterized in this work is anticipated to provide a starting point for the structure-guided discovery of selective DCLK1 inhibitors.

Doublecortin-Like Kinase 1 (DCLK1) Is a Novel NOTCH Pathway Signaling Regulator in Head and Neck Squamous Cell Carcinoma.

Despite recent advancements, the 5 year survival of head and neck squamous cell carcinoma (HNSCC) hovers at 60%. DCLK1 has been shown to regulate epithelial-to-mesenchymal transition as well as serving as a cancer stem cell marker in colon, pancreatic and renal cancer. Although it was reported that DCLK1 is associated with poor prognosis in oropharyngeal cancers, very little is known about the molecular characterization of DCLK1 in HNSCC. In this study, we performed a comprehensive transcriptome-based computational analysis on hundreds of HNSCC patients from TCGA and GEO databases, and found that DCLK1 expression positively correlates with NOTCH signaling pathway activation. Since NOTCH signaling has a recognized role in HNSCC tumorigenesis, we next performed a series of in vitro experiments in a collection of HNSCC cell lines to investigate the role of DCLK1 in NOTCH pathway regulation. Our analyses revealed that DCLK1 inhibition, using either a pharmacological inhibitor or siRNA, resulted in substantially decreased proliferation, invasion, migration, and colony formation. Furthermore, these effects paralleled downregulation of active NOTCH1, and its downstream effectors, HEY1, HES1 and HES5, whereas overexpression of DCLK1 in normal keratinocytes, lead to an upregulation of NOTCH signaling associated with increased proliferation. Analysis of 233 primary and 40 recurrent HNSCC cancer biopsies revealed that high DCLK1 expression was associated with poor prognosis and showed a trend towards higher active NOTCH1 expression in tumors with elevated DCLK1. Our results demonstrate the novel role of DCLK1 as a regulator of NOTCH signaling network and suggest its potential as a therapeutic target in HNSCC.

DCLK1 Inhibition Sensitizes Colorectal Cancer Cells to Radiation Treatment.

Colorectal cancer (CRC) is one of the most prevalent diagnosed cancers and a common cause of cancer-related mortality. Despite effective clinical responses, a large proportion of patients undergo resistance to radiation therapy. Therefore, the identification of efficient targeted therapy strategies would be beneficial to overcome cancer radioresistance. Doublecortin-like kinase 1 (DCLK1) is an intestinal and pancreatic stem cell marker that showed overexpression in a variety of cancers. The transfection of DCLK1 siRNA to ‎normal HCT-116 cells was performed, and then cells were irradiated with X-rays. The effects of DCLK1 inhibition on cell survival, apoptosis, cell cycle, DNA damage response (ATM and γH2AX proteins), epithelial-mesenchymal transition (EMT) related genes (vimentin, N‐cadherin, and E-cadherin), cancer stem cells markers (CD44, CD133, ALDH1, and BMI1), and β‐catenin signaling pathway (β‐catenin) were evaluated. DCLK1 siRNA downregulated DCLK1 expression in HCT-116 cells at both mRNA and protein levels (P <0.01). Colony formation assay showed a significantly reduced cell survival in the DCLK1 siRNA transfected group in comparison with the control group following exposure to 4 and 6 Gy doses of irradiation (P <0.01). Moreover, the expression of cancer stem cells markers (P <0.01), EMT related genes (P <0.01), and DNA repair proteins including pATM (P <0.01) and γH2AX (P <0.001) were significantly decreased in the transfected cells in comparison with the nontransfected group after radiation. Finally, the cell apoptosis rate (P <0.01) and the number of cells in the G0/G1 phase in the silencing DCLK1 group was increased (P <0.01). These findings suggest that DCLK1 can be considered a promising therapeutic target for the treatment of radioresistant human CRC.

DCLK1 inhibition attenuates tumorigenesis and improves chemosensitivity in esophageal squamous cell carcinoma by inhibiting β-catenin/c-Myc signaling.

Doublecortin-like kinase 1 (DCLK1) is involved in tumorigenesis, tumor growth and metastasis, and epithelial-to-mesenchymal transition in many digestive tract tumors. It is reportedly highly expressed in Barrett's esophagus and esophageal adenocarcinoma, but its effects on the occurrence and progression of esophageal squamous cell carcinoma (ESCC) remain unclear. In this study, real-time PCR and western blot analysis confirmed significant upregulation of DCLK1 expression in human ESCC tissues and cell lines. CCK-8 assay showed that transfection with siRNA against DCLK1 (si-DCLK1) markedly inhibited cell proliferation and colony formation in the ESCC cell lines Eca109 and TE1. Transwell assay revealed that si-DCLK1 transfection inhibited the migratory and invasive capacities of Eca109 and TE1 cells. Moreover, si-DCLK1 increased the chemosensitivity of these cells to cisplatin, as indicated by inhibited cell viability and colony formation, and increased ROS and apoptosis in cisplatin-treated cells. Western blot assay revealed that expression of nuclear β-catenin and c-Myc was significantly increased in ESCC tissues and that si-DCLK1 markedly downregulated nuclear β-catenin and c-Myc in Eca109 cells. Treatment with lithium chloride, an activator of β-catenin signaling, partially abolished the si-DCLK1-induced inhibition of proliferation, migration, invasion, and chemoresistance of ESCC cells. These findings suggest that knockdown of DCLK1 may inhibit the progression of ESCC by regulating proliferation, migration, invasion, and chemosensitivity via suppressing the β-catenin/c-Myc pathway, supporting a promising therapeutic target against ESCC.

DCLK1 Regulates Tumor Stemness and Cisplatin Resistance in Non-small Cell Lung Cancer via ABCD-Member-4

Chemoresistance cells have features similar to cancer stem cells. Elimination of these cells is an effective therapeutic strategy to clinically combat chemoresistance non-small cell lung cancer (NSCLC). Here, we demonstrate that Doublecortin-like kinase1 (DCLK1) is the key to developing chemoresistance and associated stemness in NSCLC. DCLK1 is highly expressed in human lung adenocarcinoma and strongly correlated with stemness. Silencing DCLK1 inhibits NSCLC cell primary and secondary spheroid formation, which is the prerequisite feature of tumor stem cells. DCLK1 inhibition reduced NSCLC cell migration/invasion in vitro and induced tumor growth inhibition in vivo. NSCLC cells responded differently to cisplatin treatment; indeed, the clonogenic ability of all NSCLC cells was reduced. We found that the cisplatin-resistant NSCLC cells gain the expression of DCLK1 compared with their parental control. However, DCLK1 inhibition in cisplatin-resistance NSCLC cells reverses the tumor cell resistance to cisplatin and reduced tumor self-renewal ability. Specifically, we found that DCLK1-mediated cisplatin resistance in NSCLC is via an ABC subfamily member 4 (ABCD4)-dependent mechanism. Our data demonstrate that increased expression of DCLK1 is associated with chemoresistance and enhanced cancer stem cell-like features in NSCLC. Targeting DCLK1 using gene knockdown/knockout strategies alone or in combination with cisplatin may represent a novel therapeutic strategy to treat NSCLC.

Discovery of a selective inhibitor of doublecortin like kinase 1.

Doublecortin like kinase 1 (DCLK1) is an understudied kinase that is upregulated in a wide range of cancers, including pancreatic ductal adenocarcinoma (PDAC). However, little is known about its potential as a therapeutic target. We leveraged chemoproteomic profiling and structure-based design to develop the first selective, in vivo-compatible chemical probe of the DCLK1 kinase domain, DCLK1-IN-1. We demonstrate activity of DCLK1-IN-1 against clinically relevant patient-derived PDAC organoid models and use a combination of RNA sequencing, proteomics and phosphoproteomics analysis to reveal that DCLK1 inhibition modulates proteins and pathways associated with cell motility in this context. DCLK1-IN-1 will serve as a versatile tool to investigate DCLK1 biology and establish its role in cancer.

Abstract 3443: Doublecortin-like kinase 1 (DCLK1) is novel Notch pathway signaling regulator in HNSCC

Abstract Introduction: Despite advancements in the field, the 5 year survival rate of Head and Neck Squamous Cell Carcinoma (HNSCC) still hovers at 60%. DCLK1 has been shown to regulate epithelial-to-mesenchymal transition (EMT) as well as serving as a cancer stem cell marker in colon, pancreatic and renal cancer. Although it was reported that DCLK1 is associated with poor prognosis in oropharyngeal cancers, very little is known about the molecular characterization of DCLK1 in HNSCC. Methods and Materials: In a quest for novel therapy targets for this disease, we performed an extensive and comprehensive quantitative phosphoproteomics scan on 10 HNSCC patient derived xenografts (PDXs) in order to find dysregulated phosphoproteins. We also performed a comprehensive transcriptome-based computational analysis on hundreds of HNSCC patients from TCGA and GEO databases. We used immunohistochemistry (IHC) to stain a tumor microarray (TMA) of 45 HNSCC samples. We have selected 6 cell HNSCC cell lines (JHU-011, JHU-022, JHU-029, FaDu, SCC22B and Cal27) that express DCLK1, and inhibited DCLK1 with LRRK2-in1 inhibitor and siRNA. We selected 1 HNSCC cell line with low DCLK1 expression, SCC25 and 2 normal keratinocyte cell lines, OKF6 and NOKSI, in which we overexpressed DCLK1. We assessed DCLK1 and active Notch1 expression in these cell lines by Western Blot and Immunohistochemistry (IHC). We evaluated metastatic characteristics with scratch assay, invasion assay, alamar blue proliferation assay, and colony formation assay. Results: We found that DCLK1 is hyperphosphorylated in most of the HNSCC derived PDXs. In our comprehensive transcriptome-based computational analysis on, we found that along with EMT and metastasis pathways, high DCLK1 expression also correlates with NOTCH pathway signaling signatures in HNSCC. Since Notch signaling pathway has a recognized role in tumorigenesis in HNSCC tumors, we have focused on investigating the role of DCLK1 in Notch pathway regulation. Towards this end, we performed a series of in vitro experiments in a collection of HNSCC cell lines. Our analyses revealed DCLK1 inhibition both with LRRK2in1 and siRNA resulted in substantially decreased proliferation, invasion, migration, and colony formation. Furthermore, these effects paralleled downregulation of active NOTCH1, and its downstream effectors, Hey1, Hes1 and Hes5 in all cell lines tested. Additionally, overexpression of DCLK1 in HNSCC cell lines and normal keratinocytes leads to upregulation of Notch signaling as well as increased proliferation. IHC staining on 45 HNSCC tumors indicates that 45% of the samples are positive for DCLK1 compared to 90% DCLK1 negative staining in normal oral tissue. Conclusion: Overall, our results demonstrate the novel role of DCLK1 in HNSCC as a regulator of the NOTCH signaling network and suggests its potential as a therapeutic target in HNSCC. Citation Format: Esther Channah Broner, Tejaswini Subbannayya, Alex Zhavoronkov, Mike Korzinkin, Artem Artemov, Ivan Ozerov, Ido Sloma, David Sidransky, Aditi Chatterjee, Evgeny Izumchenko. Doublecortin-like kinase 1 (DCLK1) is novel Notch pathway signaling regulator in HNSCC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3443.

Abstract 4512: Doublecortin-like kinase 1 (DCLK1) correlates with Notch pathway signaling, controls metastatic characteristics in head and neck cancer

Abstract Despite advancements in the field, the 5 year survival rate of Head and Neck Squamous Cell Carcinoma (HNSCC) still hovers at 60%. In a quest for novel therapy targets for this disease, we performed an extensive and comprehensive quantitative phosphoproteomics scan on 10 HNSCC patient derived xenografts (PDXs) in order to find dysregulated phosphoproteins. DCLK1 is hyperphosphorylated but not over expressed in most of the HNSCC derived PDXs. DCLK1 has been shown to regulate epithelial-to-mesenchymal transition (EMT) as well as serving as a cancer stem cell marker in colon and pancreas cancer. DCLK1 is also associated with bad prognosis in colon, renal and oropharyngeal cancers. We performed a comprehensive transcriptome-based computational analysis on hundreds of HNSCC patients from TCGA and GEO databases. While our results confirm the role of DCLK1 in regulating EMT and focal adhesion kinase (FAK) mediated integrin signaling, we found that high DCLK1 expression also correlates with NOTCH pathway signaling signatures in HNSCC. We have selected 5 cell HNSCC cell lines (JHU-011, JHU-022, JHU-029, FaDu and Cal29) that express DCLK1, and inhibited DCLK1 with LRRK2-in1 inhibitor and siRNA. DCLK1 inhibition resulted in substantially decreased proliferation, migration, and colony formation. Furthermore, these effects paralleled downregulation NOTCH1 signaling in all cell lines tested. Overall, our results demonstrate the novel role of DCLK1 in regulating the NOTCH signaling network and suggest its potential as a therapeutic target in HNSCC. Citation Format: Esther Channah Broner, Tejaswini Subbannayya, Jayshree Advani, Alex Zhavoronkov, Artem Artemov, Ivan Ozerov, Ido Sloma, Harsha Gowda, David Sidransky, Eugene Izumchenko, Aditi Chatterjee. Doublecortin-like kinase 1 (DCLK1) correlates with Notch pathway signaling, controls metastatic characteristics in head and neck cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4512.

Specific human cholangiocarcinoma (CCA) subpopulations of cancer stem cells (CSCs) express DoubleCortin-Like Kinase 1 (DCLK1) and DCLK1 inhibition induces anti-cancer effects

Specific human cholangiocarcinoma (CCA) subpopulations of cancer stem cells (CSCs) express DoubleCortin-Like Kinase 1 (DCLK1) and DCLK1 inhibition induces anti-cancer effects

Abstract 3888: DCLK1 is part of an EMT feedback loop and promotes colorectal cancer cell invasion and drug resistance

Abstract Colorectal cancer (CRC) is the third leading cause of cancer death in the U.S., with only a 6% 5-yr survival rate for stage IV disease. Its spread and acquisition of resistance to chemotherapy, which are fueled by the epithelial-mesenchymal transition (EMT) process and supported by tumor stem cells (TSCs), are major challenges to improving patient outcomes. New therapies that target stemness and EMT are desperately needed to prevent or delay metastasis and improve patient survival. Recently doublecortin-like kinase 1 (DCLK1) has been definitively proven to mark TSCs in CRC by two independent groups. Previous studies have demonstrated that DCLK1 is a prognostic factor in CRC and that targeted downregulation or inhibition of DCLK1 results in decreased CRC proliferation, migration, invasion, and other anti-oncogenic effects. However, the effect of overexpression of DCLK1 and its kinase active mutant on CRC has not been assessed. In this study, we investigate the correlative role of EMT and DCLK1 expression in CRC progress. Human colon cancer cells (HCT116) were infected with Lentivirus containing wild type DCLK1 or mutant DCLK1R326C cDNA sequences to overexpress DCLK1, DCLK1R326C or green fluorescent protein (GFP) cDNA sequence as control. The expressing levels of DCLK1 and EMT factors were analyzed by western blotting. The proliferative and invasive potential of these cells were compared using a MTT assay for proliferation, wound healing assay for migration, and Matrigel coated transwell assay for invasion. Knockdown of either ZEB1 or DCLK1 by specific siRNA in HCT116 cells was performed. The effects of siDCLK1 on 5-FU were performed in both HCT116 and SW480 cells using a Caspase 3/7 activity assay. Analysis of human CRC was performed using TCGA COADREAD dataset. Here we report that compared to GFP control cells, HCT116-DCLK1 and HCT116-DCLK1R326C cells exhibited a more than 20% increase in proliferation, approximately 30% increase in migration, and a 2-fold increase (p &amp;lt; 0.05) in invasion. DCLK1 expression level is decreased more than 30% by knocking down ZEB1 in HCT116 cells. In addition, knockdown DCLK1 increased 5-FU induced cell apoptosis more than 50% (P&amp;lt;0.05). Evidence from TCGA COADREAD demonstrated that EMT predicts survival in CRC patients, and increased expression level of DCLK1 in CRC patients correlate to EMT and mesenchymal phenotype. These data suggest that DCLK1 is a part of an EMT feedback-loop and may be exploited with DCLK1-targeted therapeutics for CRC. Citation Format: Dongfeng Qu, Nathaniel Weygant, William L. Berry, Randal May, Parthasarathy Chandrakesan, James J. Tomasek, Sripathi M. Sureban, Courtney Houchen, Yang Ge, Jiannan Yao, Guangyu An, Edwin Bannerman-Menson. DCLK1 is part of an EMT feedback loop and promotes colorectal cancer cell invasion and drug resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3888. doi:10.1158/1538-7445.AM2017-3888

Abstract 4147: DCLK1 a novel therapeutic target in non-small cell lung cancer

Abstract Introduction: Lung cancers possess a rare population of cells that have the capacity to self-renew, differentiation and ultimately promote tumorigenesis. These cells are often resistance to conventional therapies and are responsible for tumor relapse and metastatic spread, which contribute to the overall mortality observed in non-small cell lung cancer (NSCLC). These cells are termed tumor stem cells (TSCs) and as such are highly desirable targets for novel therapeutic strategies. Doublecortin-like Kinase 1 (DCLK1) has recently been identified as a tumor stem cell marker in the intestine and pancreas and is dysregulated in many solid tumor cancers including lung cancer. Increased expression has been demonstrated to correlate with poor survival in several solid tumor cancers. Thus these data taken together provide the rational for targeting DCLK1 expressing cells in NSCLC. Methods: Small interfering RNA (siRNA) against DCLK1 was transfected into NSCLC cell lines (A549 - wt-p53; H1299 –homozygous deletion of p53) of highly drug resistant (A549) and metastatic (H1299). Cell proliferation, colony formation, self-renewal, cell migration and invasion and drug resistance assays were performed to assess the tumor stem cell characteristics. A549 cells were treated with siDCLK1 and cisplatin in order to assess the role of DCLK1 to reverse the drug-resistance. A549 cells were utilized to generate tumor xenograft in order to assess the role of DCLK1 knockdown on NSCLC tumorigenesis in vivo. The data were generated utilizing experimental protocols for clonogenic culture, immunohistochemistry, RT-qPCR and Western blotting. Results: Silencing DCLK1 via RNA interference decreased the colony formation (p&amp;lt;0.001), and self-renewal ability (p&amp;lt;0.0001) of the NSCLC cell lines in vitro. Knocking down DCLK1 reduced (p&amp;lt;0.001) NSCLC cells migration and invasion in vitro. Furthermore, DCLK1 knockdown decreased the expression of EMT associated factors (Slug, Snail, Twist, Zeb1/2, Vimentin) and pluripotency factors. Initial cisplatin treatment results in the isolation of cisplatin resistant A549 cells. Retreatment of cisplatin resistant A549 cells results in greater resistance and survival ability. However, combination therapy of these resistance cells with siDCLK1 and cisplatin overcame cisplatin-induced resistance, resulting in greater cell death compared to cisplatin or siDCLK1 alone treatments. Nanoparticle encapsulated siDCLK1 treatment in xenograft tumors resulted in tumor growth arrest in vivo. Conclusions: NSCLC cells highly express DCLK1 display enhanced self-renewal, increased migration and invasion. Combination therapy of siDCLKL1 with cisplatin overcame cisplatin induced drug resistance. Targeting DCLK1 reduced tumor xenograft in vivo. Taken together these data suggest that DCLK1 inhibition reduces TSC related properties, overcome drug resistance and inhibits tumor growth, thus making DCLK1 targeted therapy an attractive tool for combating NSCLC. Citation Format: Parthasarathy Chandrakesan, Dongfeng Qu, Randal May, Nathaniel Weygant, William Berry, Naushad Ali, Sripathi Sureban, Eddie Bannerman-Menson, Michael Bronze, Courtney Houchen. DCLK1 a novel therapeutic target in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4147. doi:10.1158/1538-7445.AM2017-4147

Pancreatic Neuroendocrine Tumors and EMT Behavior Are Driven by the CSC Marker DCLK1.

Doublecortin-like kinase 1 (DCLK1), a marker for intestinal and pancreatic cancer stem cells, is highly expressed in neuroblastomas. This study was conducted to assess DCLK1 expression levels in pancreatic neuroendocrine tumor (PNET) tissues and to explore the roles of this molecule in clinical tissue from multiple PNET patients, cells (BON1, QGP1, and CM) and tumor xenografts. Immunohistochemically, all PNET tissues highly and diffusely expressed DCLK1 as a full-length isoform, identical to that detected in primary liver NETs. A DCLK1-overexpressing PNET cell line (QGP1-DCLK1) exhibited epithelial-mesenchymal transition (EMT)-related gene signatures, and robust upregulation of Slug (SNAI2), N-Cadherin (CDH2), and Vimentin (VIM) was validated by real-time PCR and immunoblotting. QGP1-DCLK1 cells had increased cell migration in a wound-healing assay and formed significantly larger xenograft tumors in nude mice. The factors involved in the formation of the fast-growing tumors included p-FAK (on Tyr925), p-ERK1/2, p-AKT, Paxillin, and Cyclin D1, which upon knockdown or pharmacologic inhibition of DCLK1 abolished the expression of these molecules. In conclusion, robust and ubiquitous expression of DCLK1 was first demonstrated here in human PNET tissue specimens and cells. DCLK1 characterized the PNET cell behavior, inducing p-FAK/SLUG-mediated EMT. These findings suggest the possibility of developing novel therapeutic strategies against PNETs by targeting DCLK1.Implications: Evidence here reveals that human PNETs diffusely and robustly express the cancer stem cell marker DCLK1, which drives SLUG-mediated EMT, and suggests that NETs share biological features for druggable targets with other tumors, including neuroblastoma that also highly expresses DCLK1. Mol Cancer Res; 15(6); 744-52. ©2017 AACR.

Role of cancer stem-cell marker doublecortin-like kinase 1 in head and neck squamous cell carcinoma

BackgroundSo far, no data is available on the role of the tumor stem cell marker doublecortin-like kinase 1 (DCLK1) in head and neck squamous cell carcinoma (HNSCC). The purpose of this study was to evaluate DCLK1 expression in HNSCC patients that underwent surgery and postoperative radiotherapy, and to assess its potential as a therapeutic target in vitro. MethodsWe immunohistochemically stained for DCLK1 in 127 sections of HNSCC samples obtained during surgery of HNSCC patients and correlated the expression to patients’ overall- and disease-free survival, as well as human papilloma virus (HPV) status. Additionally, we compared our survival data with data obtained from The Cancer Genome Atlas (TCGA). The effects of the DCLK1 inhibitor LRRK-2-in-1 on HNSCC cell lines alone and in combination with irradiation. ResultsExpression of DCLK1 in 127 patients was associated with poor survival. In particular, DCLK1 expression had a significant impact on survival of oropharyngeal carcinoma patients. Specifically, DCLK1+/HPV− patients had the worst prognosis after simultaneous assessment of DCLK1 and HPV status in comparison to the other three possible DCLK1/HPV constellations. Higher levels of DCLK1 mRNA were also associated with poor clinical outcome. Inhibition of DCLK1 in our HNSCC cell lines led to growth arrest and induction of apoptosis. The combination of DCLK1 inhibition with irradiation had a synergistic effect. ConclusionFirstly, DCLK1 is a prognostic biomarker for shortened survival. Secondly, through inhibition of DCLK1, it may serve as a therapeutic target as well.

Abstract 2493: Knocking down the expression of DCLK1 reduces mammary tumor formation, tumor cell self-renewal and metastasis: DCLK1 a novel therapeutic target in breast cancer

Abstract Introduction: Breast cancer is a heterogeneous disease, and is comprised of a rare population of cells that display stem cell-like properties with high metastatic potential and relative resistance to conventional therapies. Doublecortin-like Kinase 1 (DCLK1) has recently been identified as a tumor stem cell marker in the intestine and pancreas and is overexpressed in many cancers including breast cancer. In this study, we targeted DCLK1 as a novel therapeutic strategy in breast cancer cells to reduce cancer cell self-renewal, tumorigenesis and metastasis. Methods: Anti-DCLK1-siRNA was transfected into breast cancer cell lines (MCF7 [luminal] and MDAMB231 [basal-triple negative breast cancer cell line]). For analysis of circulating tumor cells, MDAMB231/MCF7 cells were stably transfected with RFP (red fluorescence protein). Tumor cell colony formation, mammosphere formation (self-renewal), cell migration and invasion were assessed to evaluate the effect of DCLK1 knockdown and or DCLK1 overexpression on breast cancer cells self-renewal and metastatic potential. Xenograft model was used to identify the role of DCLK1 on breast cancer cell growth and circulating tumor cells in vivo. The data were generated utilizing experimental protocols for clonogenic culture, circulating tumor cells, immunohistochemistry, RT-qPCR and Western blotting. Results: Expression of DCLK1 was ∼36% higher in human breast cancer tissues than in normal breast tissue. Silencing DCLK1 via RNA interference decreased the colony formation (∼70%), and self-renewal ability (∼85%), of the breast cancer cell lines in vitro. In vitro migration and invasion assays demonstrated that knocking down DCLK1 led to less (40-80%) breast cancer cells migration and invasion. Furthermore, expression of EMT associated factors (Slug, Snail, Twist, Zeb-1, Zeb-2 and Vimentin) and pluripotency factors (c-Myc, Sox2, Nanog and Oct-4) were markedly reduced between 30 and 50%, after silencing DCLK1. Inhibition of DCLK1 in xenograft tumors resulted in reduced tumor growth (∼81%) and CTCs (∼95%) in vivo. However, overexpression of DCLK1 in the non-metastatic MCF7 breast cancer cell line increased its in vitro migration and invasion potency and pluripotency along with in vivo tumor formation and progression. Conclusions: DCLK1 expression is associated with breast cancer cell self-renewal, metastasis and tumorigenesis. Targeting DCLK1 reduced breast cancer cell self-renewal, CTCs, metastasis and tumor growth. DCLK1 inhibition may represent a novel targeted therapeutic approach to reduce the morbidity and mortality associated with breast cancer. Citation Format: PARTHASARATHY CHANDRAKESAN, Nathaniel Weygant, Dongfeng Qu, William Berry, Randal May, Naushad Ali, Sripathi Sureban, Eddie Bannerman-Menson, Michael Schlosser, Courtney Houchen. Knocking down the expression of DCLK1 reduces mammary tumor formation, tumor cell self-renewal and metastasis: DCLK1 a novel therapeutic target in breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2493.