Proteomics uncover EPHA2 as a potential novel therapeutic target in colorectal cancer cell lines with acquired cetuximab resistance.

BACKGROUND: In metastatic colorectal cancer (mCRC), acquired resistance against anti-EGFR targeted monoclonal antibodies, such as cetuximab (CET), was shown to be frequently caused by activating alterations in the RAS genes KRAS or NRAS. To this day, no efficient follow-up treatment option has emerged to treat mCRC in such a setting of resistance. METHODS: To uncover potential targets for second-line targeted therapies, we used mass-spectrometric proteomics to shed light on kinome reprogramming in an established cellular model of acquired, KRAS-associated CET resistance. RESULTS: This CET resistance was reflected by significant changes in the kinome, most of them individual to each cell line. Interestingly, all investigated resistant cell lines displayed upregulation of the Ephrin type-A receptor 2 (EPHA2), a well-known driver of traits of progression. Expectedly resistant cell lines displayed increased migration (p < 0.01) that was significantly reduced by targeting the EPHA2 signalling axis using RNA interference (RNAi) (p < 0.001), ephrin-A1 stimulation (p < 0.001), dasatinib (p < 0.01), or anti-EPHA2 antibody treatment (p < 0.001), identifying it as an actionable target in mCRC with acquired CET resistance. CONCLUSION: These results highlight EPHA2 and its role in mCRC with KRAS-gene mutated acquired CET resistance and support its use as a potential actionable target for the development of future precision medicine therapies

TTF-1 Action on the Transcriptional Regulation of Cyclooxygenase-2 Gene in the Rat Brain

We have recently found that thyroid transcription factor-1 (TTF-1), a homeodomain-containing transcription factor, is postnatally expressed in discrete areas of the hypothalamus and closely involved in neuroendocrine functions. We now report that transcription of cyclooxygenase-2 (COX-2), the rate limiting enzyme in prostaglandin biosynthesis, was inhibited by TTF-1. Double immunohistochemistry demonstrated that TTF-1 was expressed in the astrocytes and endothelial cells of blood vessel in the hypothalamus. Promoter assays and electrophoretic mobility shift assays showed that TTF-1 inhibited COX-2 transcription by binding to specific binding domains in the COX-2 promoter. Furthermore, blocking TTF-1 synthesis by intracerebroventricular injection of an antisense oligomer induced an increase of COX-2 synthesis in non-neuronal cells of the rat hypothalamus, and resulted in animals' hyperthermia. These results suggest that TTF-1 is physiologically involved in the control of thermogenesis by regulating COX-2 transcription in the brain

Biomarker alterations associated with distinct patterns of metastatic spread in colorectal cancer

AbstractMetastatic spread is the most important life-threatening feature of colorectal cancer and is supposed to be mainly driven by alterations in different carcinogenic pathways. The present study compared mutation and expression profiles of distinctive biomarkers in colorectal cancer patients with different clinical metastatic patterns. As for a case-control study, patients were matched according to T category, grading and primary tumour site. Overall, 246 patients with either exclusive lung metastasis (N = 82), exclusive liver metastasis (N = 82) or non-metastatic colorectal cancer (N = 82) were identified. Paraffin-embedded specimens were examined for mutations in the RAS and RAF genes and for the expression of β-catenin and CD133. Clinical endpoints were presence or absence of distant metastasis, formation of metastasis in lungs versus the liver and survival. MAPK pathway mutations in either the KRAS, NRAS or BRAF gene were associated with the development of lung metastasis (63.4%) compared to the control group (47.6%; p = 0.04). MAPK pathway alterations plus high β-catenin expression were associated with metastasis to the lungs but not to the liver (28.0% vs. 13.4%; p = 0.02). High CD133 expression correlated with the development of liver metastasis compared to the control group (30.5% vs. 14.6%; p = 0.02). This data indicates that different patterns of distant spread are associated with specific biomarker alterations and may represent different molecular subtypes of colorectal cancer. However, underlying mechanisms of metastasis formation in different anatomic sites remains unclear. Since knowledge of the anticipated site of distant spread would substantially impact clinical management, further research is needed to identify solid biomarkers for different metastatic patterns.</jats:p

Analysis of genetic variants of frequently mutated genes in human papillomavirus-negative primary head and neck squamous cell carcinoma, resection margins, local recurrences and corresponding circulating cell-free DNA.

Background: Head and neck squamous cell carcinoma remains a substantial burden to global health. Despite evolving therapies, 5-year survival is &lt;50% and unlike in other cancers, reliable molecular biomarkers to guide treatment do not exist. Methods: We performed targeted panel next-generation sequencing to analyse somatic variants from primary and recurrent tumour tissue, corresponding resection margins and cell-free DNA from intra-operatively collected plasma samples from eight patients with human papillomavirus-negative head and neck squamous cell carcinoma. Patients were primarily treated with curative-intent surgery and received subsequent adjuvant treatment. Results: The most frequently mutated gene was TP53. Other mutated genes included NOTCH1, NF1 and CDKN2A among others. A total of 20.8% of variants were shared between primary tumour and resection margin. Out of all the variants detected, 37.5% were shared between cell-free DNA and primary tumour, whereas 12.5% were commonly found in cell-free DNA, primary tumour and resection margin. Mutational profiling was able to distinguish between a locoregional recurrence and a second primary tumour by identifying a different TP53 mutation in the primary tumour compared to the recurrent tumour in addition to private FBXW7 and CTNNB1 mutations. We also identified identical TP53 and PIK3CA mutations in another primary tumour and corresponding recurrence. Conclusion: Molecular profiling of cell-free DNA and resection margins has potential applications in clinical practice to guide future treatment decisions