N-3 Long Chain Fatty Acids Supplementation, Fatty Acids Desaturase Activity, and Colorectal Cancer Risk: A Randomized Controlled Trial

AUTHORS

Harvey J. Murff, Martha J. Shrubsole, Qiuyin Cai, Timothy Su, Jennings H. Dooley, Sunny S. Cai, Wei Zheng & Qi Daic

ABSTRACT

Introduction

n-3 long-chain polyunsaturated fatty acids (LCPUFA) have anti-inflammatory effects and may reduce colorectal cancer risk. The purpose of this study was to evaluate the effects of n-3 LCPUFA supplementation on markers of rectal cell proliferation and apoptosis and examine how genetic variation in desaturase enzymes might modify this effect.

Methods

We conducted a randomized, double-blind, control six-month trial of 2.5 grams of n-3 LCPUFA per day compared to olive oil. Study participants had a history of colorectal adenomas. Randomization was stratified based on the gene variant rs174535 in the fatty acid desaturase 1 enzyme (FADS1). Our primary outcome was change in markers of rectal epithelial proliferation and apoptosis.

Results

A total of 141 subjects were randomized. We found no difference in apoptosis markers between participants randomized to n-3 LCPUFA compared to olive oil (P = 0.41). N-3 LCPUFA supplementation increased cell proliferation in the lower colonic crypt compared to olive oil (P = 0.03) however baseline indexes of proliferation were different between the groups at randomization. We found no evidence that genotype modified the effect.

Conclusions

Our study did not show evidence of a proliferative or pro-apoptotic effect on n-3 LCPUFA supplementation on rectal mucosa regardless of the FADS genotype.

Inhibition of endothelin-B receptor signaling synergizes with MAPK pathway inhibitors in BRAF mutated melanoma

AUTHORS

Alexander Schäfer, Benedicte Haenig, Julie Erupathil, Panja Strickner, Daniela Sabato, Richard W. D. Welford, Lhéanna Klaeylé, Elise Simon, Clemens Krepler, Patricia Brafford, Min Xiao, Meenhard Herlyn, Matthias Gstaiger, Francois Lehembre & Imke Renz

ABSTRACT

The clinical benefit of MAPK pathway inhibition in melanoma patients carrying BRAF mutations is temporal. After the initial response to treatment, the majority of tumors will develop resistance and patients will relapse. Here we demonstrate that the endothelin-endothelin receptor B (ETBR) signaling pathway confers resistance to MAPK pathway inhibitors in BRAF mutated melanoma. MAPK blockade, in addition to being anti-proliferative, induces a phenotypic change which is characterized by increased expression of melanocyte-specific genes including ETBR. In the presence of MAPK inhibitors, activation of ETBR by endothelin enables the sustained proliferation of melanoma cells. In mouse models of melanoma, including patient-derived xenograft models, concurrent inhibition of the MAPK pathway and ETBR signaling resulted in a more effective anti-tumor response compared to MAPK pathway inhibition alone. The combination treatment significantly reduced tumor growth and prolonged survival compared to therapies with MAPK pathway inhibitors alone. The phosphoproteomic analysis revealed that ETBR signaling did not induce resistance towards MAPK pathway inhibitors by restoring MAPK activity, but instead via multiple alternative signaling pathways downstream of the small G proteins GNAq/11. Together these data indicate that a combination of MAPK pathway inhibitors with ETBR antagonists could have a synergistically beneficial effect in melanoma patients with hyperactivated MAPK signaling pathways.

High-Grade Uterine Sarcoma with BCOR Internal Tandem Duplication Presenting With Total Uterine Inversion

AUTHORS

T J Greenwell, S Kumar, C Hysell

ABSTRACT

High-grade uterine sarcomas are rare mesenchymal tumors in which the underlying genetics of many have been recently elucidated. BCOR internal tandem duplications are present in a subset of high-grade uterine sarcomas. We report a diagnostically challenging case of a high-grade uterine sarcoma with a BCOR internal tandem duplication presenting with total uterine inversion. The case is that of a 24 year old G0P0 female with a four month history of intermittent diffuse abdominal pain and abnormal uterine bleeding. Pelvic examination revealed a mass protruding to the hymenal ring. The patient was suspected of having a prolapsed fibroid through the cervix, and a myomectomy was planned. During the procedure, total uterine inversion was noted as a result of a submucosal mass emanating from the uterine apex. The mass was removed off a broad base using sharp dissection, and the uterus was reverted in a subsequent procedure. Grossly, the mass was polypoid, rubbery, and measured 7 cm in greatest dimension. It was grey-white to red-brown, variegated, and fibrotic with focal hemorrhagic areas.

Histologically, the neoplasm had variable cellularity with spindle cells and a myxoid background. There was diffuse mild to moderate cytologic atypia and areas of increased mitotic activity. Tongue-like growth was present at the interface of the tumor with the normal myometrium. The neoplastic cells showed strong immunoreactivity for cyclin D1, BCOR, and TRK. There was focal immunoreactivity for CD10, and ALK was negative. Next-generation sequencing was performed and demonstrated an insertion into the BCOR gene, consistent with a diagnosis of high- grade uterine sarcoma with BCOR internal tandem duplication. In conclusion, we report an interesting presentation of a high-grade uterine sarcoma with BCOR internal tandem duplication causing total uterine inversion. The morphologic features and immunohistochemical profile suggested the possibility of the entity, and next generation sequencing confirmed the diagnosis.