Doublecortin-like kinase 1 promotes hepatocyte clonogenicity and oncogenic programming via non-canonical β-catenin-dependent mechanism

Abstract

Chronic liver injury is a risk factor for cirrhosis and hepatocellular carcinoma (HCC). The molecular mechanisms that regulate the decision between normal injury repair and neoplastic initiation are unclear. Doublecortin-like kinase 1 (DCLK1), a tumor stem cell marker, is induced during cirrhosis and HCC. Here, we demonstrate that DCLK1-overexpressing primary human hepatocytes formed spheroids in suspension cultures. Spheroids derived from DCLK1-overexpressing hepatoma cells showed high level expression of active β-catenin, α-fetoprotein, and SOX9, suggesting that DCLK1 overexpression induces clonogenicity and dedifferentiated phenotypes in hepatoma cells. DCLK1 overexpression in hepatoma cells also increased phosphorylation of GSK-3β at Ser 9. This was associated with an induction of a 48-kDa active β-catenin with a preserved hypophosphorylated N-terminus that interacted with nuclear TCF-4 resulting in luciferase reporter activity and cyclin D1 expression. DCLK1 downregulation inhibited 48-kDa β-catenin expression. The proteasome inhibitor bortezomib did not block the 48-kDa β-catenin, instead, caused a threefold accumulation, suggesting a proteasome-independent mechanism. Liver tissues from patients with cirrhosis and HCC revealed epithelial co-staining of DCLK1 and active β-catenin, and cleaved E-cadherin. Repopulated DCLK1overexpressing primary human hepatocytes in humanized FRG mouse livers demonstrated active β-catenin. In conclusion, DCLK1 regulates oncogenic signaling and clonogenicity of hepatocytes by a novel non-canonical/atypical β-catenin-dependent mechanism. Hepatocellular carcinoma (HCC) is the second most common cause of cancer-related mortality and accounts for approximately 745,000 deaths per year worldwide 1. Chronic liver injury due to hepatitis B/C viral infections (HBV and HCV), metabolic disorders, and alcohol are the major risk factors for HCC 2. Recent reports using genetic lineage tracing models have demonstrated that mature hepatocytes are the cells of origin in injuryinduced HCC 3. Tumorigenesis in the liver is attributable to hepatocyte plasticity, defined as the ability of the mature hepatocytes to undergo phenotype change usually by dedifferentiation or transdifferentiation into a preneoplastic precursor cell-type 4-6. The existing paradigm that hepatic facultative stem/progenitor cells are activated to produce different cell types during liver injury has been challenged in favor of hepatocyte plasticity 5,7,8. This intuitive concept rests upon observations that mature hepatocytes retain the capacity to undergo rapid division

Targeting Doublecortin-Like Kinase 1 (DCLK1)-Regulated SARS-CoV-2 Pathogenesis in COVID-19

“…Both DCLK1 and S100A9 are highly expressed in CLD, including fatty liver, cirrhosis, and hepatocellular carcinoma. To determine whether SARS-CoV-2-infected cells with high DCLK1 expression have increased viral replication, we used primary human hepatocytes (PHHs) cultured cells on thin Matrigel layers to retain plasticity and lineages ( 15 , 23 ). The ACE2 viral receptor was highly expressed under these conditions ( Fig.…”

“…We previously showed that doublecortin-like kinase 1 (DCLK1) is induced by tissue injury and inflammation in the liver, lung, and gastrointestinal tract ( 13 , 14 ). DCLK1 is a multifunctional protein known for its involvement in clonogenicity, stemness, and tumorigenesis ( 15 – 18 ). It catalyzes tubulin polymerization that facilitates intracellular molecular transport and the replication of several viruses (e.g., adenoviruses, herpesviruses, and influenza viruses) ( 19 ).…”

“…DCLK1 also contains a kinase domain that phosphorylates multiple substrates, including the Spen family transcriptional repressor and cyclin-dependent kinase 11B ( 20 ). Our previous work showed that DCLK1 overexpression enhances the replication of the hepatitis C virus, a positive-strand RNA virus, by regulating microtubule dynamics ( 15 , 21 , 22 ). In contrast, downregulating DCLK1 inhibited hepatitis C virus replication and slowed the growth of hepatocellular carcinoma ( 23 ).…”

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

“…It was suggested that DCLK1 regulates migration, invasion and cell motility via activation of EMT (43), an important process for cancer initiation, cancer metastasis, and secondary tumor formation. However, expression of DCLK1 was also associated with impaired DNA repair (57,58), upregulation of WNT/b-catenin (59,60), RAS (13,61), PI3K/AKT (62) and VEGF (63,64) signaling, suggesting a multifaceted role of DCLK1 in cancer initiation and progression. Concordantly, our analysis of TCGA-HNSC dataset indicates that in HNSCC, tumors expressing higher DCLK1 mRNA levels were enriched for pathways that have been implicated in the EMT and CSC maintenance (such as NOTCH, WNT, TGFb, and hedgehog signaling), as well as for RAS and angiogenesis cascades.…”

DCLK1 and its interaction partners: An effective therapeutic target for colorectal cancer (Review)

“…Overexpression of DCLK1 in primary human hepatocytes has been demonstrated to form spheroids in suspension cultures. Furthermore, these cells express high levels of β-catenin, α-fetoprotein and SOX9, suggesting that DCLK1 can induce clonogenicity in hepatoma cells ( 48 ). Table I illustrates the role of DCLK1 in three of the most prevalent types of cancer.…”