Changes of microenvironment in an in vitro co-culture system

Oncotarget, 2014

Background: The progression of malignant tumors does not depend exclusively on the autonomous properties of cancer cells; it is also influenced by tumor stroma reactivity and is under strict microenvironmental control. By themselves, stromal cells are not malignant, and they maintain normal tissue structure and function. However, through intercellular interactions or by paracrine secretions from cancer cells, normal stromal cells acquire abnormal phenotypes that sustain cancer cell growth and tumor progression. In their dysfunctional state, fibroblast and immune cells produce chemokines and growth factors that stimulate cancer cell growth and invasion. In our previous work, we established an in vitro model based on a monolayer co-culture system of healthy human fibroblasts (HFs) and human osteosarcoma cells (the MG-63 cell line) that simulates the microenvironment of tumor cells and healthy cells. The coexistence between MG-63 cells and HFs allowed us to identify the YKL-40 protein as the main marker for verifying the influence of tumor cells grown in contact with healthy cells. Methods: In this study, we evaluated the interactions of HFs and MG-63 cells in a transwell co-culture system over 24 h, 48 h, 72 h, and 96 h. We analyzed the contributions of these populations to the tumor microenvironment during cancer progression, as measured by multiple markers. We examined the effect of siRNA knockdown of YKL-40 by tracking the subsequent changes in gene expression within the co-culture. We validated the expression of several genes, focusing on those involved in cancer cell invasion, inflammatory responses, and angiogenesis: TNF alpha, IL-6, MMP-1, MMP-9, and VEGF. We compared the results to those from a transwell co-culture without the YKL-40 knockdown. Results: In a pro-inflammatory environment promoted by TNF alpha and IL-6, siRNA knockdown of YKL-40 caused a down-regulation of VEGF and MMP-1 expression in HFs. Conclusions: These findings demonstrated that the tumor microenvironment has an influence on the gene expression of healthy surrounding tissues and on the process of tumorigenicity and it is emerging as attractive targets for therapeutic strategies.

Cancer Cell International, 2014

Background: The role of the microenvironment during the initiation and progression of carcinogenesis is thought to be of critical importance, both for the enhanced understanding of fundamental cancer biology as well as for improving molecular diagnostics and therapeutics. The aim of this study was to establish an in vitro model based on a co-culture of healthy human fibroblasts (HFs) and human osteosarcoma cells (MG-63s) to simulate the microenvironment including tumor and healthy cells.

Journal of Cellular and Molecular Medicine, 2009

Oncotarget, 2016

The tumor microenvironment contributes to cancer progression, in part through interactions between tumor and normal stromal cells. This study analyzed morphological and molecular changes induced in co-cultured human fibroblasts (HFs) and the MG-63 osteosarcoma cell line. Co-cultured cell monolayers were morphologically analyzed using high resolution scanning electron microscopy (HR-SEM), and trans-well assays were performed to assess cell migration and invasion. Proteins involved in inflammatory responses, cancer cell invasion, and angiogenesis were assessed using western blotting. HR-SEM showed progressive spatial orientation loss by fibroblasts in contact with MG-63s, while MG-63s proliferated rapidly and invaded HF space. Trans-well assays showed enhanced MG-63 migration in the presence of HFs. IL-6 expression was increased in co-cultured HFs, possibly stimulated by TNF-α. HFs do not normally express YKL-40 but did so in co-culture. Band densitometric analyses showed that increasing YKL-40 expression was followed by VEGF overexpression, especially in MG-63s. Finally, our results confirmed fibroblasts as the main matrix metalloproteinase source in this tumor microenvironment. Our study sheds new light on how tumor-stroma interactions promote tumor development and progression, and may support identification of novel anti-cancer therapeutics.

Biomarkers of the Tumor Microenvironment, 2017

Cancer Research, 2004

We have investigated the interaction between tumor cells and specific cells in their microenvironment using myeloma as a model. The role of myeloma-induced osteoclastogenesis in the disease was studied ex vivo. Myeloma plasma cells freshly purified from patients’ bone marrow attracted committed osteoclast (OC) precursors (n = 9; P < 0.01) and in 22 experiments directly induced their differentiation to multinucleated, bone-resorbing OCs (P < 0.00002) in a receptor activator of nuclear factor-κB ligand-mediated mechanism that was inhibited by the receptor activator of nuclear factor-κB (RANK-Fc) in 13 experiments by 71 ± 12% (P < 0.008). In contrast, myeloma cells did not induce differentiation of peripheral blood mononuclear cells. Myeloma plasma cells cocultured with OCs retained their viability and proliferative activity for >13 weeks. After 14 days in coculture, the plasma cells from 29 patients had higher viability (P < 2 × 10−6), fewer apoptotic cells (P < 4 × ...

British Journal of Cancer, 2008

The preferential proliferation of cancer cells in the bone microenvironment is poorly characterized. Expression pattern of bone marrow and other organs microenvironment in contact with osteolytic (Walker W256) and osteoblastic (MatLyLu MLL) metastases were investigated.

Journal of Cancer Research Updates, 2020

All tumors are surrounded by complex environmental components including blood and lymph vessels; cellular components like fibroblasts, endothelial cells, immune cells; and non-cellular stromal cytokines, extracellular vesicles, and extracellular matrix. All of these along with the tumor cells constitute the tumor microenvironment (TME). Also the physical and chemical factors within this tumor microenvironment including extracellular pH, hypoxia, elevated interstitial fluid pressure, and fibrosis closely associate with the tumor progression at local site, its metastasis to remote areas of the body, immunosuppression, and drug resistance exhibited by the tumor. These cellular and extracellular components of TME primarily contribute to the process of carcinogenesis. This review focuses on multiple factors that alter the microenvironment to make it favorable for tumor growth at primary site and its metastasis to secondary sites. Also some of the natural products that may help to treat the tumor conditions via alteration of this microenvironment are mentioned which may provide new venues for development of newer drugs halting the progression of the tumors.

Academia Green Energy, 2024

Electrical power supply is inadequate in Nigeria and most remote settlements in the country are not connected to the national grid. This study, therefore, investigates a set of possible off-grid hybrid power systems that can satisfy the electrical load of a model rural community of 100 households in Kaduna and Katsina States, Northwestern region of Nigeria at the lowest energy cost. Two off-grid hybrid power systems and a stand-alone diesel generator are modelled, simulated and analysed for the two locations with different solar and wind energy resources using HOMER software. The optimisation results show that a Wind-PV-Diesel hybrid power system will be able to satisfy their load demand with the least cost in the two locations. The Net Present Cost (NPC) and cost of energy (COE) for the optimal system are: $ 435,818 and 0.203 $/kWh for Kaduna and $ 322,091 and 0.150 $/kWh for Katsina. Thus, the optimal system in Katsina has lower NPC than the optimal system in Kaduna. The reduction in NPC for the optimal system in Katsina is due to the high wind penetration in the hybrid system, as cost of wind energy per kilowatt is lower than that of PV and Diesel generators. In comparison to grid tariff in Nigeria, the reported cost of energy in this study is cost effective for rural settlements that are far from the existing grid. Thus a hybrid PV-Wind system is recommended for Katsina, while a Hybrid PV-Wind-Diesel system is more suitable for Kaduna.

Cultivating equanimity through mindfulness meditation: A mixed methods enquiry into the development of decentering capabilities in men.