Characteristics of cultured desmoid cells with different CTNNB1 mutation status

Novel insights into biomarkers of progression in Desmoid tumor

Desmoid tumor (DT) is a rare neoplasm characterized by the proliferation of myofibroblastic cells that infiltrates and invades adjacent tissues. Due to its locally aggressive and recurrent nature, DT often causes local symptoms and can be challenging to manage clinically. Therefore, identifying biomarkers that can predict the progression of DT and guide treatment decisions is critical. This review summarizes several biomarkers that have been implicated in active surveillance (AS) and the prediction of postoperative recurrence and attempts to elucidate their underlying mechanisms. Some of these novel markers could provide prognostic value for clinicians, and ultimately help facilitate optimal and accurate therapeutic decisions for DT.

Efficacy of auranofin as an inhibitor of desmoid progression

Anticancer drugs and molecular targeted therapies are used for refractory desmoid-type fibromatosis (DF), but occasionally cause severe side effects. The purpose of this study was to identify an effective drug with fewer side effects against DF by drug repositioning, and evaluate its efficacy. FDA-approved drugs that inhibit the proliferation of DF cells harboring S45F mutations of CTNNB1 were screened. An identified drug was subjected to the investigation of apoptotic effects on DF cells with analysis of Caspase 3/7 activity. Expression of β-catenin was evaluated with western blot analysis, and immunofluorescence staining. Effects of the identified drug on in vivo DF were analyzed using Apc1638N mice. Auranofin was identified as a drug that effectively inhibits the proliferation of DF cells. Auranofin did not affect Caspase 3/7 activity compared to control. The expression level of β-catenin protein was not changed regardless of auranofin concentration. Auranofin effectively inhibited the development of tumorous tissues by both oral and intraperitoneal administration, particularly in male mice. Auranofin, an anti-rheumatic drug, was identified to have repositioning effects on DF. Since auranofin has been used for many years as an FDA-approved drug, it could be a promising drug with fewer side effects for DF.

Differentially Methylated Regions in Desmoid-Type Fibromatosis: A Comparison Between CTNNB1 S45F and T41A Tumors

Introduction

The majority of desmoid-type fibromatosis (DTF) tumors harbor a β-catenin mutation, affecting specific codons in CTNNB1 exon 3. S45F tumors are reported to have a higher chance of recurrence after surgery and more resistance to systemic treatments compared to wild-type (WT) and T41A tumors. The aim of this pilot study was to examine the genome-wide DNA methylation profiles of S45F and T41A mutated DTF, to explain the observed differences in clinical behavior between these DTF subtypes.

Material and Methods

Genome-wide analysis of DNA methylation was performed using MeD-seq on formalin-fixed, paraffin-embedded primary DTF samples harboring a S45F (n = 14) or a T41A (n = 15) mutation. Differentially methylated regions (DMRs) between S45F and T41A DTF were identified and used for a supervised hierarchical cluster analysis. DMRs with a fold-change ≥1.5 were considered to be differentially methylated and differences between S45F and T41A tumors were quantitatively assessed. The effect of DMRs on the expression of associated genes was assessed using an independent mRNA expression dataset. Protein-protein interactions between WT β-catenin and mutant variants and DNA methyltransferase 1 (DNMT1) were examined by immunoprecipitation experiments.

Results

MeD-seq analyses indicated 354 regions that displayed differential methylation. Cluster analysis yielded no distinct clusters based on mutation, sex, tumor site or tumor size. A supervised clustering based on DMRs between small (≤34 mm) and large (>87 mm) DTF distinguished the two groups. Only ten DMRs displayed a fold change of ≥1.5 and six of them were found associated with the following genes: NLRP4, FOXK2, PERM1, CCDC6, NOC4L, and DUX4L6. The effects of DMRs on gene expression yielded a significant difference (p < 0.05) in the expression between S45F and T41A for CCDC6 and FOXK2 but not for all Affymetrix probe-sets used to detect these genes. Immunoprecipitations did not reveal an association of WT β-catenin or mutant variants with DNMT1.

Conclusion

This study demonstrated that S45F and T41A DTF tumors did not exhibit gross differences in DNA methylation patterns. This implies that distinct DNA methylation profiles are not the sole determinant for the divergent clinical behavior of these different DTF mutant subtypes.

β-Catenin in desmoid-type fibromatosis: deep insights into the role of T41A and S45F mutations on protein structure and gene expression

Desmoid‐type fibromatosis (DF) is a rare mesenchymal lesion with high risk of local recurrence. Specific β‐catenin mutations (S45F) appeared to be related to this higher risk compared to T41A‐mutated or wild‐type (WT). We explored the influence of both mutations and WT on structure stability and affinity of β‐catenin for α‐catenin and the pattern of gene expression that may influence DF behavior. Using 33 surgically resected primary DFs harboring T41A (n = 14), S45F (n = 10), or WT (n = 9), we performed a comparative molecular analysis by protein/protein interaction modeling, gene expression by DASL microarrays, human inflammation gene panel, and assessment of immune system‐based biomarkers by immunohistochemistry. Mutated proteins were more stable than WT and formed a weaker complex with α‐catenin. Consensus unsupervised gene clustering revealed the presence of two DF group‐mutated (T41A + S45F) and WT (P = 0.0047). The gene sets ‘Inflammatory‐Defense‐Humoral Immune Response’ and ‘Antigen Binding’ were significantly enriched in T41A. The deregulation of 16 inflammation‐related genes was confirmed. Low numbers of T cells and tumor‐associated macrophages (TAM) infiltrating the tumors and low/absent PD‐1/PD‐L1 expression were also identified. We demonstrated that mutated DFs (T41A or S45F) and WT are two distinct molecular subgroups with regard to β‐catenin stability, α‐catenin affinity, and gene expression profiling. A different inflammation signature characterized the two mutated groups, suggesting mediation either by T41A or by S45F. Finally, all mutated cases showed a low number of TIL and TAM cells and a low or absent expression of PD‐1 and PD‐L1 consistent with β‐catenin activation insensitive to checkpoint blockade.

FH535 Inhibits Proliferation and Motility of Colon Cancer Cells by Targeting Wnt/β-catenin Signaling Pathway

Aberrant Wnt/β-catenin pathway activation is frequently observed in human colorectal cancer (CRC) and has become a promising target for CRC treatment. Our study aimed to evaluate the effect of FH535, a small molecule inhibitor of Wnt/β-catenin pathway, on two colon cancer cell lines, HT29 and SW480. We found FH535 significantly inhibited colon cancer cell proliferation in vitro and induced cell cycle arrest. Moreover, FH535 inhibited colon cancer xenograft growth in vivo. Wound-healing assay and Transwell assay revealed that FH535 notably suppressed migration and invasion of SW480 cells. FH535 also repressed expression of cancer stem cell markers, CD24, CD44 and CD133 in HT29 cells. Real time-quantitative PCR and Western blotting revealed that targeting Wnt/β-catenin pathway using FH535 effectively downregulated target genes including cyclin D1 and survivin at mRNA and protein level, which contributed to the FH535-induced inhibitory effect on colon cancer cell proliferation. As mechanisms for suppressing cancer cell motility, FH535 downregulated expression of matrix metalloproteinase-7 and -9, Snail and vimentin. RNA sequencing revealed that FH535 prominently altered multiple biological pathways associated with DNA replication, cell cycle and metabolism. Our study highlights the anti-cancer effect of FH535 on colon cancer and presents its potential in colon cancer treatment.

Immunohistochemical staining with non-phospho β-catenin as a diagnostic and prognostic tool of COX-2 inhibitor therapy for patients with extra-peritoneal desmoid-type fibromatosis

Background

Immunohistochemical staining with conventional anti-β-catenin antibody has been applied as a diagnostic tool for desmoid-type fibromatosis (DF). This study aimed to evaluate the diagnostic and prognostic value of immunohistochemical staining with anti-non-phospho β-catenin antibody, which might more accurately reflect the aggressiveness of DF, in comparison to the conventional anti-β-catenin antibody.

Methods

Between 2003 and 2015, 40 patients with extra-peritoneal sporadic DF were prospectively treated with meloxicam or celecoxib, a COX-2 inhibitor, therapy. The efficacy of this treatment was evaluated according to Response Evaluation Criteria in Solid Tumors (RECIST). Immunohistochemical staining was performed on formalin-fixed material to evaluate the expression of β-catenin and non-phospho β-catenin, and the positivity was grouped as negative, weak, moderate, and strong. DNA was isolated from frozen tissue or formalin-fixed materials, and the CTNNB1 mutation status was determined by direct sequencing.

Results

Of the 40 patients receiving COX-2 inhibitor treatment, there was one with complete remission, 12 with partial remission, 7 with stable disease, and 20 with progressive disease. The mutation sites in CTNNB1 were detected in 22 (55%) of the 40 cases: T41A (17 cases), S45F (3 cases), and T41I and S45P (1 each). The positive nuclear expression of non-phospho β-catenin showed a significant correlation with positive CTNNB1 mutation status detected by Sanger method (p = 0.025), and poor outcome in COX-2 inhibitor therapy (p = 0.022). In contrast, nuclear expression of β-catenin did not show a significant correlation with either CTNNB1 mutation status (p = 0.43) or outcome of COX-2 inhibitor therapy (p = 0.38).

Conclusions

Nuclear expression of non-phospho β-catenin might more appropriately reflect the biological behavior of DF, and immunohistochemical staining with non-phospho β-catenin could serve as a more useful diagnostic and prognostic tool of COX-2 inhibitor therapy for patients with DF.

Characteristics of cultured desmoid cells with different CTNNB1 mutation status

Desmoid tumors are benign mesenchymal neoplasms with a locally aggressive nature. The mutational status of β‐catenin gene (CTNNB1) is presumed to affect the tumorous activity of the cells. In this study, we isolated three kinds of desmoid cell with different CTNNB1 status, and compared their characteristics. Cells were isolated from three patients with abdominal wall desmoid during surgery, all of which were resistant to meloxicam treatment. The mutational status of the CTNNB1 exon 3 was determined for both parental tumor tissues and isolated cultured cells. β‐catenin expression was determined with immunohistochemistry. Responsiveness to meloxicam was investigated with MTS assay together with COX‐2 immunostaining. mRNA expressions of downstream molecules of Wnt/β‐catenin pathway were determined with real‐time RT‐PCR. Three kinds of cell isolated from desmoid tumors harboring different CTNNB1 mutation status (wild type, T41A, and S45F), all exhibited a spindle shape. These isolated cells could be cultured until the 20th passage with unchanged proliferative activity. Nuclear accumulation of β‐catenin was observed in all cultured cells, particularly in those with S45F. Proliferating activity was significantly suppressed by meloxicam (25 μmol/L, P < 0.007) in all three cell cultures, of which parental desmoid was resistant to meloxicam clinically. The mRNA expressions of Axin2, c‐Myc, and Cyclin D1 differently increased in the three cultured cell types as compared with those in human skin fibroblast cells (HDF). Inhibitors of Wnt/β‐catenin pathway downregulated Axin2, c‐Myc, and Cyclin D1 significantly. Isolated and cultured desmoid tumor cells harboring any one of the CTNNB1 mutation status had unique characteristics, and could be useful to investigate desmoid tumors with different mutation status of CTNNB1.