Influence of tumor cell culture supernatants on macrophage functional polarization: in vitro models of macrophage-tumor environment interaction.

AIMS AND BACKGROUND: Macrophages are heterogeneous cells with extensive functional plasticity; they can change their functional profiles repeatedly in response to environmental changes anywhere between their extreme phenotypical programs (labeled as M1 and M2 polarization, respectively). In terms of antitumoral immune response, M1 macrophages are considered to be beneficial, while M2 macrophages supposedly promote tumor progression. Tumor-associated macrophages (TAMs) represent a major leukocyte population present in many tumors. Although many studies indicate that TAMs elicit several M2-associated protumoral functions, including promotion of angiogenesis, matrix remodeling and suppression of adaptive immunity, their role regarding tumor progression is still controversial. The aim of the present study was to develop an appropriate in vitro model to study the effect of tumor-secreted soluble factors on the functional phenotype of macrophages. METHODS AND STUDY DESIGN: THP-1 human monocytic line cells and peripheral blood mononuclear cells from healthy volunteers were used for macrophage differentiation; primary tumor cell culture supernatants or tumor cell line supernatants were employed along with various cytokines, growth factors and other stimuli to design different model variants and to better mimic the in vivo tumor microenvironment. RESULTS: The cytokine secretion patterns of these macrophages suggest that primary tumor cell culture supernatants are able to switch the macrophage phenotype or to induce functional polarization of macrophages toward a mixed M1/M2 phenotype. Conclusions. These data support the hypothesis that TAM behavior is modulated by the tumor microenvironment itself.

Serum perioperative profile of cytokines in patients with squamous cell carcinoma of the larynx.

OBJECTIVE: Altered immune, inflammatory, and angiogenesis responses have been noticed in head and neck cancer, and many of these responses have been associated with a poor clinical outcome. The objective of this study was to evaluate several immune mediators in the sera of patients with squamous cell carcinoma (SCC) of the larynx undergoing curative surgery in connection with clinicopathologic factors. METHODS: Multiplex analysis of cytokines (interleukin [IL]-6, IL-8, IL-10, tumour necrosis factor α [TNF-α], interferon-γ [IFN-γ]), chemokines (monocyte chemoattractant protein 1 [MCP-1], macrophage inflammatory protein 1α [MIP-1α], and epithelial neutrophil-activating protein 78 [ENA-78]), and growth factors (vascular endothelial growth factor and basic fibroblast growth factor) in the serum of patients with laryngeal cancer and healthy controls was performed using xMap technology. RESULTS: Patients with SCC presented an altered cytokine profile compared to healthy controls, both preoperatively (higher levels of IL-8 and IL-10) and postoperatively (higher values for IL-6, IL-8, IL-10, and TNF-α). Heavy smoking was associated with significantly lower levels of ENA-78 and higher levels of IL-8. CONCLUSION: Differences noticed in patients' immune mediator profiles seem to be attributable to both disease and treatment. Further longitudinal studies are necessary to elucidate the involvement of immune mediators in disease progression and clinical evolution.

Primary cell culture of human adenocarcinomas--practical considerations.

Cell culture is one of the major tools for oncology research, being an excellent system in which to study the biochemistry and molecular biology associated with individual cancer types and to understand cancer cell physiology. Progress in understanding the biology of any type of carcinoma has been impeded by the inability to culture adequately malignant cells from most epithelial tissues. The ultimate in vitro tumor model would completely reflect the in vivo tumor microenvironment in function and mechanism. Unfortunately, such a model does not currently exist. Homogeneous cell lines that can be continuously propagated on plastic surfaces have been extensively used as a surrogate for tumor environment; however they are very different from the in vivo tumor cells. Model systems involving primary culture represent the situation most closely related to the original tissue although they have a number of disadvantages over cell lines, such as the limited ability to repeat studies with a well characterized culture system that can be used in multiple laboratories. The primary culture may contain many types of stromal and infiltrating cell types potentially complicating the interpretation of data. Yet, their properties better reflect the cellular interactions present in intact tissue. The present article reviews the critical steps in obtaining, routine maintenance and cryopreservation of primary tumor cell cultures, based on information from literature and personal experience on the subject. The article also includes an updated protocol for primary tumor cell isolation and culture.