Identification of lysyl oxidase as an adipocyte-secreted mediator that promotes a partial mesenchymal-to-epithelial transition in MDA-MB-231 cells

Aim: Breast cancer (BC) is the most common cancer in women worldwide, where adiposity has been linked to BC morbidity. In general, obese premenopausal women diagnosed with triple-negative BC (TNBC) tend to have larger tumours with more metastases, particularly to the bone marrow, and worse prognosis. Previous work using a 3-dimensional (3D) co-culture system consisting of TNBC cells, adipocytes and the laminin-rich extracellular matrix (ECM) trademarked as Matrigel, demonstrated that adipocytes and adipocyte-derived conditioned media (CM) caused a partial mesenchymal-to-epithelial transition (MET). Given that MET has been associated with secondary tumour formation, this study sought to identify molecular mediators responsible for this phenotypic change. Methods: Adipocytes were cultured with and without Matrigel, where semi-quantitative proteomics was used to identify proteins whose presence in the CM was induced or enhanced by Matrigel, which were referred to as adipocyte-secreted ECM-induced proteins (AEPs). The AEPs identified were assessed for association with prognosis in published proteomic datasets and prior literature. Of these, 4 were evaluated by the reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA), followed by a functional and MET marker analysis of 1 AEP on MDA-MB-231 cells grown on Matrigel or as monolayers. Results: The 4 AEPs showed a positive correlation between protein expression and poor prognosis. RT-qPCR analysis reported no significant change in AEPs mRNA expression. However, lysyl oxidase (LOX) was increased in CM of ECM-exposed adipocytes. Recombinant LOX (rLOX) caused the mesenchymal MDA-MB-231 TNBC cells to form less branched 3D structures and reduced the expression of vimentin. Conclusions: The data suggest that adipocyte-secreted LOX changes the mesenchymal phenotype of BC cells in a manner that could promote secondary tumour formation, particularly at sites high in adipocytes such as the bone marrow. Future efforts should focus on determining whether targeting LOX could reduce BC metastasis in obese individuals

Assessment of fracture risk in a cohort of Egyptian female Systemic Lupus erythematosus patients

Aim of the work: To assess the fracture risk in a cohort of Egyptian systemic lupus erythematosus (SLE) females in correlation to some disease variables. Patients and methods: Seventy female SLE patients ≥40 years old were enrolled with detailed history taking, assessment of disease activity and damage index. Measurement of Serum calcium, phosphorus and alkaline phosphatase, bone mineral density (BMD) by dual emission X-ray absorptiometry (DEXA) at lumbar spine (LS) and femoral neck (FN), serum osteocalcin level and World Health Organization (WHO) fracture risk assessment tool (FRAX®). Results: 20% of the patients had LS osteoporosis, 35.7% LS osteopenia, 8.6% FN osteoporosis, and 42.9% FN osteopenia. Ten-year risk of major and hip fractures was high in SLE patients evidenced by FRAX-Major ≥20% in 10% of patients, and FRAX-Hip ≥3% in 27.1% of patients. Serum osteocalcin level was significantly decreased in SLE patients with lower BMD than those with normal BMD, and significantly decreased in patients with osteoporosis than those with osteopenia. A significant negative correlation was found between osteocalcin level and age of patients, disease duration, disease activity and damage index scores, current intravenous pulse and cumulative steroids, immunosuppressants, anticoagulants, but there was a positive correlation with antimalarials and calcium supplements. Conclusion: Ten-year risk of major and hip fractures was high in SLE patients. Increasing age, disease duration, high anti-DNA titres, higher disease activity and damage index were associated with a higher fracture risk. FRAX predicted fractures among SLE patients with normal and low bone mass not just those with frank osteoporosis. Physicians should be alerted to the higher risk of future fractures in SLE patients for periodic monitoring. Keywords: Systemic lupus erythematosus, Bone mineral density, Osteoporosis, Fracture risk, Fracture risk assessment too