FZD6 (Frizzled Class Receptor 6)

A kinome-wide CRISPR-Cas9 knockout screen reveals that FZD6 inhibition sensitizes prostate cancer cells to the inhibition of PKMYT1, a WEE kinase family member. Collectively, we demonstrate that targeting a single FZD receptor highly expressed in prostate cancers can yield significant therapeutic efficacy, and uncover therapeutic vulnerabilities associated with FZD6 inhibition.

To further dissect its mechanism, Wnt signalling was perturbed using siRNA against GSK3β, β-catenin and ICG-001 (a CBP/β-catenin interaction inhibitor), and their combination...This study identifies miR-195-5p as a potent regulator of CSCs and proliferation, and modulator of the Wnt signalling cascade. Co-inhibition of GSK3β and CBP/β-catenin through miR-195-5p highlights its therapeutic potential in combating stemness and proliferation in breast cancer.

Screening of SAG1.3 derivatives identified compound 11 that competed with BODIPY-cyclopamine binding at different FZDs and inhibited WNT-induced FZD dynamics and β-catenin signaling in HEK293 cells. Furthermore, compound 11 blocked WNT-3A-induced Lgr5 gene expression in human primary hepatocyte spheroids and reduced the viability of RNF43-mutated but not RNF43-wildtype pancreatic cancer cells. Based on our data, we suggest that compound 11 acts on FZDs to limit WNT- and WNT-surrogate-induced receptor dynamics providing a valid proof-of-concept for targeting FZDs with small molecule compounds.

In pancreatic cancer samples, overexpression of Wnt ligands, FZD receptors, and β-catenin is associated with the presence of distant metastasis and poor clinical outcomes. In conclusion, this pathway represents a promising avenue for identifying novel diagnostic, prognostic, and therapeutic biomarkers in GI cancers, warranting further clinical investigation.

Finally, β-catenin knockdown enhanced pyroptosis and decreased 5-FU resistance. Thus, FZD6 promotes 5-FU resistance in CRC cells by inhibiting pyroptosis through increased nuclear translocation of β-catenin.

Rescue experiments established the hierarchical regulatory axis: miR-194-5p inhibition and FZD6 ablation partially reversed the TMZ-sensitizing effects of circ0059511 knockdown. Our work unveils the circ0059511/miR-194-5p/FZD6 axis as a central mediator of TMZ resistance in glioblastoma, providing a rationale for combinatorial therapeutic strategies to overcome chemoresistance.

SMAD7 is a downstream component of FZD6 signaling that is thought to mediate FZD6-associated phenotypes, at least in part. Therefore, FZD6/WNT7B-SMAD7 can be considered a tumor-promoting signaling pathway in HGSOC that may be responsible for tumor growth, peritoneal metastasis, and chemoresistance.

This study uncovers relevant functions of EpCAM where Wnt receptors are upregulated via the transcriptional co-factor activity of EpICD. The resultant enhancement of Wnt signaling induces γ-secretase activity further stimulating EpICD cleavage and its nuclear translocation. Our humanized anti-EpCAM antibody hEpAb2-6 blocks these mechanisms and may thereby provide therapeutic benefit in CRC.

In accordance, tissue-specific expression patterns of FZD homologues correlate with the incidence of RNF43 or ZNRF3 cancer mutations in those tissues. Consequently, our data point to druggable vulnerabilities of specific FZD receptors in RNF43- or ZNRF3-mutant human cancers.

WMP significantly inhibits CAC tumorigenesis by up-regulating PPARα-mediated fatty acid oxidation, inhibiting the Wnt signaling pathway-mediated EMT, and suppressing CCL3/CCR1-mediated inflammatory responses.

Mutagenesis along with imaging and functional analysis on the human lens epithelial tissues suggested potential crosstalk between the G-protein coupling of FZD6 and the PCP signaling pathways. Together, this study provides an integrated understanding of FZD structure and function, and lays the foundation for developing therapeutic modulators to activate or inhibit FZD signaling for a range of disorders including cancers and cataracts.

Furthermore, the knockdown of SOX8 decreased the phospho-GSK3β level and suppressed Frizzled-6 (FZD6) transcription; restoration of FZD6 expression partially abolished the effect of SOX8 on Wnt/β-catenin signaling and promote CRC cell proliferation. In conclusion, our findings suggested that SOX8 served as an oncogene in CRC through the activation of FZD6-dependent Wnt/β-catenin signaling.