Dickkopf-related protein 1, a new biomarker for local immune status and poor prognosis among patients with colorectal liver Oligometastases: a retrospective study

Dickkopf-1 is an immune infiltration-related prognostic biomarker of head and neck squamous cell carcinoma

Immunotherapy is currently one of the most viable therapies for head and neck squamous cell carcinoma (HNSCC), characterized by high immune cell infiltration. The Wnt-signaling inhibitor and immune activation mediator, Dickkopf-1 (DKK1), has a strong correlation with tumor growth, tumor microenvironment, and, consequently, disease prognosis. Nevertheless, it is still unclear how DKK1 expression, HNSCC prognosis, and tumor-infiltrating lymphocytes are related. To better understand these associations, we examined how DKK1 expression varies across different tumor and normal tissues. In our study, we investigated the association between DKK1 mRNA expression and clinical outcomes. Next, we assessed the link between DKK1 expression and tumor immune cell infiltration. Additionally, using immunohistochemistry, we evaluated the expression of DKK1 in 15 healthy head and neck tissue samples, and the expression of CD3, CD4, and DKK1 in 27 HNSCC samples. We also explored aberrant DKK1 expression during tumorigenesis. DKK1 expression was remarkably higher in HNSCC tissues than in healthy tissues, and was shown to be associated with tumor stage, grade, lymph node metastasis, histology, and a dismal clinical prognosis in HNSCC. DKK1 expression in HNSCC tissues was inversely correlated with CD3+ (P < 0.0001) and CD4+ (P < 0.0001) immune cell infiltration, while that in immune cells was inversely associated with HNSCC prognosis. These findings offer a bioinformatics perspective on the function of DKK1 in HNSCC immunotherapy and provide justification for clinical research on DKK1-targeted HNSCC treatments. DKK1 is a central target for improving the efficacy of HNSCC immunotherapy.

Dickkopf 1 is expressed in normal fibroblasts during early stages of colorectal tumorigenesis

BACKGROUND AND PURPOSE

Colorectal cancer progression from adenoma to cancer is a time-intensive process; however, the interaction between normal fibroblasts (NFs) with early colorectal tumors, such as adenomas, remains unclear. Here, we analyzed the response of the microenvironment during early tumorigenesis using co-cultures of organoids and NFs.

MATERIALS AND METHODS

Colon normal epithelium, adenoma, cancer organoid, and NFs were established and co-cultured using Transwell inserts. Microarray analysis of NFs was performed to identify factors expressed early in tumor growth. Immunostaining of clinical specimens was performed to localize the identified factor. Functional analysis was performed using HCT116 cells. Serum DKK1 levels were measured in patients with colorectal cancer and adenoma.

RESULTS

Colorectal organoid-NF co-culture resulted in increased organoid diameter and cell viability in normal epithelial and adenomatous organoids but not in cancer organoids. Microarray analysis of NFs revealed 18 genes with increased expression when co-cultured with adenoma and cancer organoids. Immunohistochemical staining revealed DKK1 expression in the tumor stroma from early tumor growth. DKK1 stimulation reduced HCT116 cell proliferation, while DKK1 silencing by siRNA transfection increased cell proliferation. Serum DKK1 level was significantly higher in patients with advanced cancer and adenoma than in controls. Serum DKK1 level revealed area-under-the-curve values of 0.78 and 0.64 for cancer and adenoma, respectively.

CONCLUSION

These findings contribute valuable insights into the early stages of colorectal tumorigenesis and suggest DKK1 as a tumor suppressor. Additionally, serum DKK1 levels could serve as a biomarker to identify both cancer and adenoma, offering diagnostic possibilities for early-stage colon tumors. The present study has a few limitations. We considered using DKK1 as a candidate gene for gene transfer to organoids and NFs; however, it was difficult due to technical problems and the slow growth rate of NFs. Therefore, we used cancer cell lines instead. In addition, immunostaining and ELISA were based on the short-term collection at a single institution, and further accumulation of such data is desirable. As described above, most previous reports were related to advanced cancers, but in this study, new findings were obtained by conducting experiments on endoscopically curable early-stage tumors, such as adenomas.

Oral administration of M13-loaded nanoliposomes is safe and effective to treat colitis-associated cancer in mice

OBJECTIVE

Colitis-associated cancer (CAC) treatment lacks effective small-molecule drugs and efficient targeted delivery systems. Here, we loaded M13 (an anti-cancer drug candidate) to colon-targeting ginger-derived nanoliposomes (NL) and investigated if orally administered M13-NL could enhance the anticancer effects of M13 in CAC mouse models.

METHODS

The biopharmaceutical properties of M13 were assessed by physicochemical characterizations. The in vitro immunotoxicity of M13 was assessed against PBMCs using FACS and the mutagenic potential of M13 was evaluated by the Ames assay. The in vitro efficacy of M13 was tested in 2D- and 3D-cultured cancerous intestinal cells. AOM/DSS-induced CAC mice were used to evaluate the therapeutic effects of free M13 or M13-NL on CAC in vivo.

RESULTS

M13 has beneficial physiochemical properties, including high stability, and no apparent immunotoxicity or mutagenic potential in vitro. M13 is effective against the growth of 2D- and 3D-cultured cancerous intestinal cells in vitro. The in vivo safety and efficacy of M13 were significantly improved by using NL for drug delivery (p < 0.001). Oral administration of M13-NL exhibited excellent therapeutic effects in AOM/DSS-induced CAC mice.

CONCLUSION

M13-NL is a promising oral drug formulation for CAC treatment.

Combination of Wnt/β-Catenin Targets S100A4 and DKK1 Improves Prognosis of Human Colorectal Cancer

Metastasis is directly linked to colorectal cancer (CRC) patient survival. Wnt signaling through β-catenin plays a key role. Metastasis-inducing S100A4 is a Wnt/β-catenin target gene and a prognostic biomarker for CRC and other cancer types. We aimed to identify S100A4-dependent expression alterations to better understand CRC progression and metastasis for improved patient survival. S100A4-induced transcriptome arrays, confirmatory studies in isogenic CRC cell lines with defined β-catenin genotypes, and functional metastasis studies were performed. S100A4-regulated transcriptome examination revealed the transcriptional cross-regulation of metastasis-inducing S100A4 with Wnt pathway antagonist Dickkopf-1 (DKK1). S100A4 overexpression down-regulated DKK1, S100A4 knock-down increased DKK1. Recombinant DKK1 reduced S100A4 expression and S100A4-mediated cell migration. In xenografted mice, systemic S100A4-shRNA application increased intratumoral DKK1. The inverse correlation of S100A4 and DKK1 was confirmed in five independent publicly available CRC expression datasets. Combinatorial analysis of S100A4 and DKK1 in two additional independent CRC patient cohorts improved prognosis of overall and metastasis-free survival. The newly discovered transcriptional cross-regulation of Wnt target S100A4 and Wnt antagonist DKK1 is predominated by an S100A4-induced Wnt signaling feedback loop, increasing cell motility and metastasis risk. S100A4 and DKK1 combination improves the identification of CRC patients at high risk.

Adenomatous polyposis coli in cancer and therapeutic implications

Inactivating mutations of the adenomatous polyposis coli (APC) gene and consequential upregulation of the Wnt signaling pathway are critical initiators in the development of colorectal cancer (CRC), the third most common cancer in the United States for both men and women. Emerging evidence suggests APCmutations are also found in gastric, breast and other cancers. The APC gene, located on chromosome 5q, is responsible for negatively regulating the b-catenin/Wnt pathway by creating a destruction complex with Axin/Axin2, GSK-3b, and CK1. In the event of an APC mutation, b-catenin accumulates, translocates to the cell nucleus and increases the transcription of Wnt target genes that have carcinogenic consequences in gastrointestinal epithelial stem cells. A literature review was conducted to highlight carcinogenesis related to APC mutations, as well as preclinical and clinical studies for potential therapies that target steps in inflammatory pathways, including IL-6 transduction, and Wnt pathway signaling regulation. Although a range of molecular targets have been explored in murine models, relatively few pharmacological agents have led to substantial increases in survival for patients with colorectal cancer clinically. This article reviews a range of molecular targets that may be efficacious targets for tumors with APC mutations.

Dkk1 inhibits malignant transformation induced by Bmi1 via the β-catenin signaling axis in WB-F344 oval cells

Dickkopf-1 (Dkk1) is an inhibitor of Wnt signaling involved in cancer cell proliferation, apoptosis, and migration and angiogenesis. It was previously reported that B cell-specific Moloney mouse leukemia virus integration site 1 (Bmi1) activates the Wnt pathway by inhibiting the expression of DKK1 in breast cancer cell lines and 293T cells. Bmi1 and DKK1 are highly expressed in liver samples taken by biopsy from patients with hepatitis B virus-related hepatocellular carcinoma (HCC), but the effect of both Bmi1 and DKK1 on the carcinogenesis of adult hepatic stem cells (oval cells) has not previously been reported. In this study, we used WB-F344 cells to explore the function and regulation of Dkk1 upon Bmi1 treatment. Overexpression of Dkk1 repressed differentiation, proliferation, and migration induced by Bmi1 but promoted the apoptosis of hepatic WB-F344 oval cells. In addition, Dkk1 reduced the enhancement of β-catenin levels induced by Bmi1. Finally, we used transcriptome sequencing to perform a comprehensive evaluation of the transcriptome-related changes in WB-F344 oval cells induced by Dkk1 and Bmi1. These results may provide evidence for future studies of the pathogenesis of HCC and the design of possible therapies.

Wnt/β-catenin signaling as an emerging potential key pharmacological target in cholangiocarcinoma

Cholangiocarcinoma (CCA) is a fatal malignant tumor of biliary epithelial cells involving intra- or extra-hepatic bile ducts. The prognosis of CCA is generally poor due to its diagnosis at the late stages. The currently employed chemotherapeutic agents do not increase the survival rate in patients with unresectable CCA. Accordingly, there is a need to identify new therapeutic agents for the effective management of intra- and extra-hepatic CCA. Clinical as well as preclinical studies have suggested the key role of the activation of Wnt/β-catenin signaling pathway in the induction and progression of CCA. There is an up-regulation of different Wnt ligands including Wnt2, Wnt3, Wnt5, Wnt7 and Wnt10 along with redistribution of β-catenin (more expression in the nucleus and lesser on the cell surface due to nuclear translocation of β-catenin) in different types of malignant biliary tumors. Apart from the role of this pathway in the induction and progression of CCA, this pathway is also involved in inducing multidrug resistance by inducing the expression of P-glycoprotein efflux pump on the cancer cells. These deleterious effects of Wnt/β-catenin signaling are mediated in association with other signaling pathways involving microRNAs (miRNAs), PI3K/AKT/PTEN/GSK-3β, retinoic acid receptors (RARs), dickkopf-1 (DKK1), protein kinase A regulatory subunit 1 α (PRKAR1A/PKAI), (SLAP), liver kinase B1 (LKB1) and CXCR4. The selective inhibitors of Wnt/β-catenin signaling may be potentially employed to overcome multidrug-resistant, fatal CCA. The present review discusses the role of Wnt/β-catenin along with its relation with other signaling pathways in the induction and progression of CCA.

Dickkopf 1 impairs the tumor response to PD-1 blockade by inactivating CD8+ T cells in deficient mismatch repair colorectal cancer

BACKGROUND

Dickkopf 1 (DKK1) is associated with tumor progression. However, whether DKK1 influences the tumor response to programmed cell death protein 1 (PD-1) blockade in colorectal cancers (CRCs) with deficient mismatch repair (dMMR) or microsatellite instability (MSI) has never been clarified.

METHODS

Tumor tissues from 80 patients with dMMR CRC were evaluated for DKK1 expression and immune status via immunohistochemistry. Serum DKK1 was measured in another set of 43 patients who received PD-1 blockade therapy. CT26 cells and dMMR CRC organoids were cocultured with T cells, and CT26-grafted BALB/c mice were also constructed. T-cell cytotoxicity was assessed by apoptosis assays and flow cytometry. The pathway through which DKK1 regulates CD8+ T cells was investigated using RNA sequencing, and chromatin immunoprecipitation and luciferase reporter assays were conducted to determine the downstream transcription factors of DKK1.

RESULTS

Elevated DKK1 expression was associated with recurrence and decreased CD8+ T-cell infiltration in dMMR CRCs, and patients with high-serum DKK1 had a poor response to PD-1 blockade. RNA interference or neutralization of DKK1 in CRC cells enhanced CD8+ T-cell cytotoxicity, while DKK1 decreased T-bet expression and activated GSK3β in CD8+ T cells. In addition, E2F1, a downstream transcription factor of GSK3β, directly upregulated T-bet expression. In organoid models, the proportion of apoptotic cells was elevated after individual neutralization of PD-1 or DKK1 and was further increased on combined neutralization of PD-1 and DKK1.

CONCLUSIONS

DKK1 suppressed the antitumor immune reaction through the GSK3β/E2F1/T-bet axis in CD8+ T cells. Elevated serum DKK1 predicted poor tumor response to PD-1 blockade in dMMR/MSI CRCs, and DKK1 neutralization may restore sensitivity to PD-1 blockade.

Nonalcoholic fatty liver disease and colorectal cancer: Correlation and missing links

Nonalcoholic fatty liver disease (NAFLD) is one of the major metabolic diseases that occur in almost one in every four global population, while colorectal cancer (CRC) is one of the leading causes of cancer related deaths in the world. Individuals with pre-existing NAFLD show a higher rate of developing CRC and liver metastasis, suggesting a causal relationship. Interestingly, both of these diseases are strongly associated with obesity, which is also a growing global health concern. In this current review, we will explore scientific findings that demonstrate the relationship between NAFLD, CRC and obesity, as well as the underlying mechanisms. We will also indicate the missing links and knowledge gaps that require more in-depth investigation.