WNT5A as a therapeutic target in breast cancer.

Despite the clinical development of novel adjuvant and neoadjuvant chemotherapeutic drugs, metastatic breast cancer is one of the leading causes of cancer-related death among women. The present review focuses on the relevance, mechanisms, and therapeutic potential of targeting WNT5A as a future anti-metastatic treatment strategy for breast cancer patients by restoring WNT5A signaling as an innovative therapeutic option. WNT5A is an auto- and paracrine ß-catenin-independent ligand that has been shown to induce tumor suppression as well as oncogenic signaling, depending upon cancer type. In breast cancer patients, WNT5A protein expression has been observed to be significantly reduced in between 45 and 75% of the cases and associated with early relapse and reduced disease-free survival. WNT5A triggers various downstream signaling pathways in breast cancer that primarily affect tumor cell migration and invasion. The accumulated in vitro results reveal that treatment of WNT5A-negative breast cancer cells with recombinant WNT5A caused different tumor-suppressive responses and in particular it impaired migration and invasion. The anti-migratory/invasive and anti-metastatic effects of reconstituting WNT5A signaling by the small WNT5A mimicking peptide Foxy5 form the basis for two successful clinical phase 1-studies aiming at determining safety and pharmacokinetics as well as defining dose-level for a subsequent phase 2-study. We conclude that re-installation of WNT5A signaling is an attractive and promising anti-metastatic therapeutic approach for future treatment of WNT5A-negative breast cancer patients.

Patent landscape highlighting double-edged scaffold of a WNT5A-agonizing peptide, Foxy5.

Aberrant expression of the WNT signaling pathway has been associated with cancer progression and recurrence. Research over the decades has led to development of WNT-targetable small molecules, but has faced challenges in translating to clinics. Unlike WNT/ß-catenin inhibitors, WNT5A-mimicking peptide, Foxy5 has shown encouraging efficacy in impairing metastasis of cancers with low or absent WNT5A expression. Recent patent application US20210008149 advocates the implication of Foxy5 for treatment and prevention of cancer relapse. The inventors have demonstrated the anti-stemness activity of Foxy5 in mice xenograft model via suppressing the expression of colonic cancer stem cell markers. Foxy5 also exhibits non-toxic nature when administered alone or in synergy with standard chemotherapy thus strengthening its candidature in the field of cancer therapeutics.

LGR5 Expression Predicting Poor Prognosis Is Negatively Correlated with WNT5A in Colon Cancer.

WNT/ß-catenin signaling is essential for colon cancer development and progression. WNT5A (ligand of non-canonical WNT signaling) and its mimicking peptide Foxy5 impair ß-catenin signaling in colon cancer cells via unknown mechanisms. Therefore, we investigated whether and how WNT5A signaling affects two promoters of ß-catenin signaling: the LGR5 receptor and its ligand RSPO3, as well as ß-catenin activity and its target gene VEGFA. Protein and gene expression in colon cancer cohorts were analyzed by immunohistochemistry and qRT-PCR, respectively. Three colon cancer cell lines were used for in vitro and one cell line for in vivo experiments and results were analyzed by Western blotting, RT-PCR, clonogenic and sphere formation assays, immunofluorescence, and immunohistochemistry. Expression of WNT5A (a tumor suppressor) negatively correlated with that of LGR5/RSPO3 (tumor promoters) in colon cancer cohorts. Experimentally, WNT5A signaling suppressed ß-catenin activity, LGR5, RSPO3, and VEGFA expression, and colony and spheroid formations. Since ß-catenin signaling promotes colon cancer stemness, we explored how WNT5A expression is related to that of the cancer stem cell marker DCLK1. DCLK1 expression was negatively correlated with WNT5A expression in colon cancer cohorts and was experimentally reduced by WNT5A signaling. Thus, WNT5A and Foxy5 decrease LGR5/RSPO3 expression and ß-catenin activity. This inhibits stemness and VEGFA expression, suggesting novel treatment strategies for the drug candidate Foxy5 in the handling of colon cancer patients.

The antitumor effects of WNT5A against hematological malignancies.

The bone marrow (BM) microenvironment (niche) is abnormally altered in acute myeloid leukemia (AML), leading to deficient secretion of proteins, soluble factors, and cytokines by mesenchymal stromal cells (MSC) that modifies the crosstalk between MSC and hematopoietic cells. We focused on a WNT gene/protein family member, WNT5A, which is downregulated in leukemia and correlated with disease progression and poor prognosis. We demonstrated that WNT5A protein upregulated the WNT non-canonical pathway only in leukemic cells, without modulating normal cell behavior. We also introduced a novel WNT5A-mimicking compound, Foxy-5. Our results showed reduction of crucial biological functions that are upregulated in leukemia cells, including ROS generation, cell proliferation, and autophagy, as well as G0/G1 cell cycle arrest. Additionally, Foxy-5 induced early-stage macrophage cell differentiation, a crucial process during leukemia development. At a molecular level, Foxy-5 led to the downregulation of two overexpressed leukemia pathways, PI3K and MAPK, which resulted in a disarrangement of actin polymerization with consequent impairment of CXCL12-induced chemotaxis. Notably, in a novel tri-dimensional bone marrow-mimicking model, Foxy-5 led to reduced leukemia cell growth and similar results were observed in a xenograft in vivo model. Overall, our findings highlight the pivotal role of WNT5A in leukemia and demonstrate that Foxy-5 acts as a specific antineoplastic agent in leukemia, counterbalancing several leukemic oncogenic processes related to the crosstalk in the bone marrow niche, and represents a promising therapeutic option for AML. WNT5A, a WNT gene/protein family member, is naturally secreted by mesenchymal stromal cells and contributes to the maintenance of the bone marrow microenvironment. WNT5A downregulation is correlated with disease progression and poor prognosis. The treatment with Foxy-5, a WNT5A mimetizing compound, counterbalanced several leukemogenic processes that are upregulated in leukemia cells, including ROS generation, cell proliferation, and autophagy and disruption of PI3K and MAPK signaling pathways.

The WNT5A Agonist Foxy5 Reduces the Number of Colonic Cancer Stem Cells in a Xenograft Mouse Model of Human Colonic Cancer.

BACKGROUND: The wingless-type mammary tumour virus integration site 5A (WNT5A) agonist Foxy5 was shown in vitro to affect intracellular signalling implicated in the regulation of colonic cancer stem cells (CSCs). MATERIALS AND METHODS: In order to study whether Foxy5 can modulate CSCs, either HT-29 or Caco-2 human colonic cancer cells, both lacking endogenous WNT5A expression, were inoculated subcutaneously into nude mice. RESULTS: Foxy5 reduced the expression of the stem-cell marker aldehyde dehydrogenase and, interestingly, the specific colon CSC marker double cortin-like kinase 1. Foxy5 also reduced active ß-catenin and the expression of its downstream target Achaete Scute complex homolog 2, a CSC-preserving transcription factor. Foxy5 also reduced cyclo-oxygenase 2 expression, responsible for the formation of the CSC-promoting prostaglandin E2 (PGE2), but increased that of 15-hydroxyprostaglandin dehydrogenase expression, a PGE2-degrading enzyme. Accordingly, Foxy5 impairs both ß-catenin and PGE2 signalling, both of which have been implicated in promoting the niche of colonic CSCs. CONCLUSION: Our data suggest that Foxy5 can complement the traditional adjuvant chemotherapeutic treatment to which CSCs are resistant.