lgk974 and Colorectal-Neoplasms

WNT974 is a small molecule inhibitor of Wnt signaling that specifically inhibits porcupine O-acyltransferase. This phase Ib dose--escalation study evaluated the maximum tolerated dose of WNT974 in combination with encorafenib and cetuximab in patients with BRAF V600E-mutant metastatic colorectal cancer with RNF43 mutations or RSPO fusions.. Patients received once-daily encorafenib and weekly cetuximab, in addition to once-daily WNT974, in sequential dosing cohorts. In the first cohort, patients received 10-mg WNT974 (COMBO10), which was reduced in subsequent cohorts to 7.5-mg (COMBO7.5) or 5-mg (COMBO5) after dose-limiting toxicities (DLTs) were observed. Primary endpoints were incidence of DLTs and exposure to WNT974 and encorafenib. Secondary endpoints were anti-tumor activity and safety.. Twenty patients were enrolled (COMBO10, n = 4; COMBO7.5, n = 6; COMBO5, n = 10). DLTs were observed in 4 patients, including grade 3 hypercalcemia (COMBO10, n = 1; COMBO7.5, n = 1), grade 2 dysgeusia (COMBO10, n = 1), and lipase increased (COMBO10, n = 1). A high incidence of bone toxicities (n = 9) was reported, including rib fracture, spinal compression fracture, pathological fracture, foot fracture, hip fracture, and lumbar vertebral fracture. Serious adverse events were reported in 15 patients, most frequently bone fracture, hypercalcemia, and pleural effusion. The overall response rate was 10% and disease control rate 85%; most patients achieved stable disease as their best response.. Concerns surrounding the safety and lack of preliminary evidence of improved anti-tumor activity of WNT974 + encorafenib + cetuximab, compared with previous encorafenib + cetuximab data, ultimately led to study discontinuation. Phase II was not initiated.. ClinicalTrials.gov, NCT02278133.

Topics: Antineoplastic Combined Chemotherapy Protocols; Cetuximab; Colorectal Neoplasms; Humans; Hypercalcemia; Mutation; Proto-Oncogene Proteins B-raf; Proto-Oncogene Proteins p21(ras)

Colorectal cancer (CRC) is one of the most common gastrointestinal malignancies. Despite recent advances in the treatment for CRC, resistance to chemotherapy drugs and recurrence of the tumor are among the main problems for treatment in this cancer. The MTT assay was performed to assess the cytotoxic effects of drugs on CRC cell lines (SW742 and SW480) and normal colon cells. Three-dimensional culture (spheroid) was also used to evaluate the effect of drugs on tumor cell masses. The rate of expression of genes was also evaluated using Real-Time PCR. The analysis of the results demonstrated that aspirin and LGK974 have cytotoxic effects on CRC cell lines, and in the IC50 dose, they disintegrate the cancerous cell masses. These drugs reduce the invasion and increase apoptosis in SW742 and SW480 cell lines. A decrease in the expression of WNT, AXIN, TCF and APC genes and an increase in the expression of β-catenin gene in the WNT signaling pathway were revealed. The genes involved in the MAPK signaling pathway such as ERK, JNK, KRAS and MEK showed a decrease in expression and a increase in expression of RAF gene. In the apoptotic pathway, increased expression of BAX and decreased expression of BCL-2 were reported. Also, decreased expression of P53, cyclin D1 and COX-2 was observed. This study demonstrates that aspirin and LGK974 could be effective in inhibiting the signaling pathways of WNT and MAPK, arresting cell cycle and inducing apoptosis in CRC cell lines.

Topics: Antineoplastic Agents; Apoptosis; Aspirin; Cell Cycle; Cell Line, Tumor; Colorectal Neoplasms; Gene Expression Regulation, Neoplastic; Humans; Inhibitory Concentration 50; MAP Kinase Signaling System; Oxaliplatin; Pyrazines; Pyridines; Wnt Signaling Pathway

Cancer stem cells (CSCs) are inherently resistant to chemotherapy, and CSCs in chemotherapy-failed recurrent tumors are enriched; however, the cellular origin of chemotherapy-induced CSC enrichment remains unclear. Communication with stromal fibroblasts may induce cancer cell dedifferentiation into CSCs through secreted factors. We recently demonstrated that fibroblast-derived exosomes promote chemoresistance in colorectal cancer (CRC). Here, we report that fibroblasts confer CRC chemoresistance via exosome-induced reprogramming (dedifferentiation) of bulk CRC cells to phenotypic and functional CSCs. At the molecular level, we provided evidence that the major reprogramming regulators in fibroblast-exosomes are Wnts. Exosomal Wnts were found to increase Wnt activity and drug resistance in differentiated CRC cells, and inhibiting Wnt release diminished this effect in vitro and in vivo. Together, our results indicate that exosomal Wnts derived from fibroblasts could induce the dedifferentiation of cancer cells to promote chemoresistance in CRC, and suggest that interfering with exosomal Wnt signaling may help to improve chemosensitivity and the therapeutic window.

Topics: Animals; Antineoplastic Agents; Cell Dedifferentiation; Cell Proliferation; Cells, Cultured; Colorectal Neoplasms; Drug Resistance, Neoplasm; Exosomes; Female; Fibroblasts; Fluorouracil; HT29 Cells; Humans; Mice; Mice, Inbred NOD; Mice, SCID; Neoplastic Stem Cells; Oxaliplatin; Paracrine Communication; Pyrazines; Pyridines; Wnt Signaling Pathway; Xenograft Model Antitumor Assays

Many epithelial stem cell populations follow a pattern of stochastic stem cell divisions called 'neutral drift'. It is hypothesised that neutral competition between stem cells protects against the acquisition of deleterious mutations. Here we use a Porcupine inhibitor to reduce Wnt secretion at a dose where intestinal homoeostasis is maintained despite a reduction of Lgr5+ stem cells. Functionally, there is a marked acceleration in monoclonal conversion, so that crypts become rapidly derived from a single stem cell. Stem cells located further from the base are lost and the pool of competing stem cells is reduced. We tested whether this loss of stem cell competition would modify tumorigenesis. Reduction of Wnt ligand secretion accelerates fixation of Apc-deficient cells within the crypt leading to accelerated tumorigenesis. Therefore, ligand-based Wnt signalling influences the number of stem cells, fixation speed of Apc mutations and the speed and likelihood of adenoma formation.

Topics: Acyltransferases; Adenoma; Adenomatous Polyposis Coli Protein; Animals; Carcinogenesis; Cell Transformation, Neoplastic; Colorectal Neoplasms; Enzyme Inhibitors; Intestinal Mucosa; Ligands; Membrane Proteins; Mice; Mice, Inbred C57BL; Mice, Transgenic; Pyrazines; Pyridines; Stem Cells; Wnt Signaling Pathway

In colorectal cancer (CRC), WNT pathway activation by genetic rearrangements of RSPO3 is emerging as a promising target. However, its low prevalence severely limits availability of preclinical models for in-depth characterization. Using a pipeline designed to suppress stroma-derived signal, we find that RSPO3 "outlier" expression in CRC samples highlights translocation and fusion transcript expression. Outlier search in 151 CRC cell lines identified VACO6 and SNU1411 cells as carriers of, respectively, a canonical PTPRK(e1)-RSPO3(e2) fusion and a novel PTPRK(e13)-RSPO3(e2) fusion. Both lines displayed marked

Topics: Axin Protein; Cell Line, Tumor; Cell Proliferation; Colorectal Neoplasms; Drug Resistance; Enzyme Inhibitors; Gene Fusion; Humans; Pyrazines; Pyridines; Thrombospondins; Wnt Proteins; Wnt Signaling Pathway

The DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT) is commonly overexpressed in cancers and is implicated in the development of chemoresistance. The use of drugs inhibiting MGMT has been hindered by their haematologic toxicity and inefficiency. As a different strategy to inhibit MGMT we investigated cellular regulators of MGMT expression in multiple cancers. Here we show a significant correlation between Wnt signalling and MGMT expression in cancers with different origin and confirm the findings by bioinformatic analysis and immunofluorescence. We demonstrate Wnt-dependent MGMT gene expression and cellular co-localization between active β-catenin and MGMT. Pharmacological or genetic inhibition of Wnt activity downregulates MGMT expression and restores chemosensitivity of DNA-alkylating drugs in mouse models. These findings have potential therapeutic implications for chemoresistant cancers, especially of brain tumours where the use of temozolomide is frequently used in treatment.

Topics: Animals; Antineoplastic Agents; Benzeneacetamides; beta Catenin; Brain Neoplasms; Camptothecin; Celecoxib; Cisplatin; Colorectal Neoplasms; Dacarbazine; DNA Modification Methylases; DNA Repair Enzymes; Doxorubicin; Drug Resistance, Neoplasm; Flow Cytometry; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Glioma; Glucose-6-Phosphate Isomerase; Heterocyclic Compounds, 3-Ring; Humans; Immunoblotting; Immunohistochemistry; Irinotecan; Medulloblastoma; Mice; Neoplasm Transplantation; Neoplasms; Neuroblastoma; Pyrans; Pyrazines; Pyridines; Real-Time Polymerase Chain Reaction; Sulfones; Temozolomide; Triazoles; Tumor Suppressor Proteins; Vincristine; Wnt Proteins; Wnt Signaling Pathway