Detection, enumeration, and characterization of immune cells infiltrating melanoma tumors

Mouse Model of Irritant Contact Dermatitis

Background

Irritant contact dermatitis is a common inflammatory skin disease characterized by skin barrier dysfunction, eczematous dermatitis, and chronic itching. This disease severely affects the quality of life. Considering that the current treatment approaches are not ideal, more extensive research is needed to develop new treatments. Mainly, a mouse model is needed to investigate the effectiveness of new drugs to treat this disease.

Objectives

This study was conducted to create a mouse model of irritant contact dermatitis.

Methods

In the current study, we used BALB/c female mice to prepare a mouse model of irritant contact dermatitis. To induce irritant contact dermatitis, we used a dinitrochlorobenzene mixture with acetone/olive oil as an irritant. After 10 days of application, the mouse skin tissue was isolated and examined in terms of histopathology.

Results

The introduced protocol created an irritant contact dermatitis model clinically and histopathologically.

Conclusions

In the present study, we introduced a new protocol using a mixture of dinitrochlorobenzene and acetone/olive oil to create an irritant contact dermatitis model. Mouse models have been extensively used to discover the complex mechanisms of irritant contact dermatitis and provide a preclinical platform before conducting clinical interventional research on humans to evaluate a new therapeutic approach. However, one should always look for models that cause the least pain and suffering in the animal and simultaneously are simple and reliable for the desired studies. Thus, our protocol is a new approach that can be effective and painless in creating a model of irritant contact dermatitis.

Flow Cytometric Identification of Tumor-Infiltrating Lymphocytes from Glioblastoma

We describe an isolation method of tumor-infiltrating lymphocytes (TILs) from glioblastoma tumors for the purpose of analysis by flow cytometry. This protocol is unique from many others in that the use of a selective lymphocyte isolation procedure, such as a Ficoll or Percoll gradient, is not used. We find that staining of TILs and analysis by flow cytometry is not affected by the presence of heterogeneous populations, while other selective isolation procedures can significantly decrease lymphocyte yield from already rare populations.

M1 and M2 macrophages' clinicopathological significance in cutaneous melanoma

Skin malignant melanoma (MM) is an aggressive cancer with an increasing incidence with limited therapies in advanced stages. Tumor-associated macrophages (TAMs) are the major immune constituent of the MM microenvironment and contribute toward its prognosis. TAMs' characterization and localization in human cancer is important to understand cancer progression and to identify molecular personalized therapies. M2 TAMs in stage I-II MMs are associated with worse prognostic parameters. A comprehensive M1-macrophage and M2-macrophage intratumoral localization and quantification in all stages of skin MMs is documented here with its clinical significance. To highlight immune pathways and possible early indicators of MM progression, we evaluated the number of M1 and M2 TAMs and intratumoral distribution in a large series of skin MMs. CD68 double immunostaining with MRP8-14 or inducible nitric oxide synthase (M1 macrophages) and with CD163 or CD204 (M2 macrophages) was performed in 94 stage I-IV skin MMs with a long duration of follow-up. The accumulation and distribution of M1 and M2 TAMs in intratumoral nests, stroma, and at the invasive front was correlated with clinicopathological variables. Since the early stage of MMs, M1 intratumoral macrophages were fewer than the M2 population; their recruitment was rapidly and progressively overwhelmed by an increase in M2 TAMs during MM progression. Independent of their intratumoral distribution, the accumulation of both M1 and M2 TAMs is associated with poor prognostic indicators and patients' survival. M1-recruited macrophages shift to the M2 phenotype early in MM development, possibly induced by high inducible nitric oxide synthase intratumoral increase peculiarly occurring since the initial MM stages. M2-recruited TAMs overwhelm M1 accumulation in all stages of MM progression, thus favoring neoplastic growth and dissemination. Independent of their intratumoral distribution, the prevalent accumulation of M2 TAMs in MM is statistically confirmed to be a poor indicator of patients' outcome and a potential target of immune therapies.

Molecular mechanisms of flavonoids in melanin synthesis and the potential for the prevention and treatment of melanoma

Flavonoids are becoming popular nutraceuticals. Different flavonoids show similar or distinct biological effects on different tissues or cell types, which may limit or define their usefulness in cancer prevention and/or treatment application. This review focuses on a few selected flavonoids and discusses their functions in normal and transformed pigment cells, including cyanidin, apigenin, genistein, fisetin, EGCG, luteolin, baicalein, quercetin and kaempferol. Flavonoids exhibit melanogenic or anti-melanogenic effects mainly via transcriptional factor MiTF and/or the melanogenesis enzymes tyrosinase, DCT or TYRP-1. To identify a direct target has been a challenge as most studies were not able to discriminate whether the effect(s) of the flavonoid were from direct targeting or represented indirect effects. Flavonoids exhibit an anti-melanoma effect via inhibiting cell proliferation and invasion and inducing apoptosis. The mechanisms are also multi-fold, via ROS-scavenging, immune-modulation, cell cycle regulation and epigenetic modification including DNA methylation and histone deacetylation. In summary, although many flavonoid compounds are extremely promising nutraceuticals, their detailed molecular mechanism and their multi-target (simultaneously targeting multiple molecules) nature warrant further investigation before advancement to translational studies or clinical trials.