In this study, we explored the effect of combined use of dabrafenib, a BRAF inhibitor, and cetuximab, an EGFR inhibitor, on BRAF(V600E)-mutant CRC stem cells and its possible mechanisms.
In summary, our study shows that the addition of celecoxib enhances the antitumor efficacy of cetuximab in CRC due to impairment of EGFR-RAS-FOXM1-β-catenin signaling axis.
Panitumumab is a fully human IgG2 monoclonal antibody that is highly selective for the epidermal growth factor receptor (EGFR), which is overexpressed in 25-77% of colorectal cancers and is often associated with a poor prognosis.
EGFR mutations in exon 18-21 and K-ras mutations in exon 1 and 2 were detected in tumor samples from 101 Chinese patients with CRC by polymerase chain reaction and Sanger sequencing.
In this study, we investigated the ability of two MEK inhibitors currently in clinical trials, AS703026 and AZD6244, to address the challenge posed by the resistance of K-ras mutated colorectal cancers to EGFR mAb.
The efficacy of epidermal growth factor receptor- targeted therapy is significantly associated with Kirsten rat sarcoma viral oncogene homolog (KRAS) and B-raf serine/threonine kinase proto-oncogene (BRAF) mutation in patients with colorectal cancer (CRC), for which the standard gene testing is currently performed using tumor tissue DNA.
These results reveal that KRAS G13D is responsive to neurofibromin-stimulated hydrolysis and suggest that a subset of <i>KRAS</i> G13-mutated colorectal cancers that are neurofibromin-competent may respond to EGFR therapies.
The two sets of data, clinical and in vitro, are complementary and support each other, lending strength to our contention that TIMP- 1 plasma levels can identify a subset of patients with KRAS-mutated metastatic CRC that will have benefit from EGFR-inhibition therapy.
We exemplified the applicability of the model using EGFR-gefitinib treatment for Lung Adenocarcinoma (LUAD) and Lung Squamous Cell Cancer (LSCC) and the ERK2-VTX11e treatment for melanoma and colorectal cancer.
Overall, our data suggest that gene polymorphisms active in the EGFR pathway may be associated with the sensitivity of colorectal cancer patients to platinum-based chemotherapy.
It has become clear that patients with colorectal cancer whose tumor has an activating mutation in KRAS do not respond to monoclonal antibody therapies targeting EGFR.
The response of BRAF mutant colorectal cancer to recent targeted strategies such as anti-BRAF or combinations with MEK and EGFR inhibitors remains limited and highly heterogeneous within BRAF V600E cohorts.
This is no more evident than in the recent advances in testing of colorectal cancers for specific molecular alterations in order to guide treatment with the monoclonal antibody therapies cetuximab and panitumumab, which target the epidermal growth factor receptor.
BRAF V600E also predicts poor prognosis in microsatellite stable colorectal cancers and may be a marker of resistance to anti-EGFR therapy in metastatic disease.
MEK inhibitors are being explored as a treatment option for patients with KRAS-mutant colorectal cancer who are not candidates for EGFR-directed therapies.
The US FDA approved a liquid biopsy test for EGFR activating mutations in patients with non-small cell lung cancer (NSCLC) as a companion diagnostic for therapy selection. ctDNA also allows for the identification of mutations selected by treatment such as EGFRT790M in NSCLC. ctDNA can also detect mutations such as KRAS G12V in colorectal cancer and BRAF V600E/V600K in melanoma.