Tumor-associated macrophages and individual chemo-susceptibility are influenced by iron chelation in human slice cultures of gastric cancer

Abstract

Purpose: Presence of tumor-associated macrophages (TAM) and high levels of ferritin and lipocalin 2 (Lcn2) in the tumor microenvironment are associated with poor prognosis in many types of cancer. Here we investigate whether iron deprivation influences TAM phenotype and chemotherapy resistance in tumor slice cultures (TSC) of gastric cancer. Results: TAM remained morphologically and functionally stable for four DIV. DFO treatment for 72 h decreased ferritin expression in TAM and in the tumor stroma but did not alter Lcn2 expression. TAM phenotype was altered after 72 h of cisplatin or DFO treatment compared with control conditions. Single DFO treatment and combined treatment with cytotoxic drugs significantly increased tumor cell apoptosis in TSC of gastric cancer. Methods: TSC were manufactured by cutting tissue of gastric cancer resection specimens in 350 μm thick slices and cultivating them under standard conditions on a filter membrane, at an air-liquid interface. After 24 h ex vivo , TSC were treated with irinotecan (100 nM) or cisplatin (10 μM) alone and in combination with deferoxamine (DFO; 10 μM, 100 μM), respectively, for 72 h. After four days in vitro (DIV) the TSC were fixated with paraformaldehyde, paraffin embedded and analyzed by immunohistochemistry for apoptosis (cPARP), proliferation (Ki67), TAM (CD68, CD163), ferritin, and Lcn2 expression. Conclusions: TAM are well preserved and can be studied in TSC of gastric cancer. Iron deprivation significantly increased tumor cell apoptosis.

The Iron Curtain: Macrophages at the Interface of Systemic and Microenvironmental Iron Metabolism and Immune Response in Cancer

“…In this case, high levels of FPN and low hepcidin expression demonstrates a favorable cohort of breast cancer patients with an increased survival rate ( 49 ). Macrophages associated with breast cancer express high levels of ferritin light chain that promotes the M2 macrophage phenotype and fosters a pro-tumor environment in breast cancer by secreting ferritin iron into the stroma ( 43 , 45 ). TAMs in more aggressive forms of breast cancer secrete lipocalin 2 (Lcn2), a small molecule that increases iron concentration and the iron labile pool of cancer cells within the TME to promote growth and resistance to chemotherapy ( 50 , 51 ).…”

FOXM1 Inhibition in Ovarian Cancer Tissue Cultures Affects Individual Treatment Susceptibility Ex Vivo

“…Here, we present a highly standardized tissue culture model derived from ovarian carcinoma. Tissue slice cultures were proven to maintain morphologic characteristics featuring the tumor microenvironment and depict metabolic challenges which induce hypoxic areas and limited nutrition supply, mimicking in vivo tumor conditions [ 37 , 40 , 42 , 43 ]. Preservation of morphology as well as the composition of the original tumor tissue in our cultures confirm once more the current approaches.…”

“…Although the connection of FOXM1 to the TME is not yet well understood, it is suggested to play a role in T-cell differentiation and to affect the proliferation of macrophages [ 59 , 60 ]. Considering an important influence of immune cells in cancer development and treatment, tissue cultures display a vital immunological compartment [ 40 , 61 ], and thus might help to understand the complex FOXM1 network in context of the TME and the effects of thiostrepton by modulating immune activation. While our findings have set the base for investigations on ovarian carcinoma tissue culture, further work should also take clinical patient data into consideration for correlative comparison and evaluation with ex vivo results.…”

“…The aim of the current study was to investigate the effects of thiostrepton in a more complex setting using tumor tissue cultures from patient-derived specimens. This model, established in other solid tumor entities such as gastric, lung and colorectal cancer, is capable of use to study tissue markers including FOXM1 and allows the investigation of tumor cells in their microenvironment (TME) which could play an important role in assessing drug response and interactions [ 37 , 38 , 39 , 40 ]. Comprehension of tumor cell interaction within its surrounding is key to understand the underlying mechanisms of tumor evolution and resistance development.…”

Tumor‑associated macrophages: Role in the pathological process of tumorigenesis and prospective therapeutic use (Review)

“…Three primary strategies are described: i) Drugs that are able to modulate the activity of TAMs; ii) designed carriers for targeted drug delivery to macrophages, TAMs or specific pro-tumor M2-TAMs; and iii) the use of macrophages to target the tumor. At present, research regarding TAMs is largely focused on an increased interest in the search for markers characterizing functionally different subpopulations of macrophages associated with tumor progression and the effectiveness of chemotherapy, which may result in identification of potential targets for treatment (13)(14)(15)(16)(17)(18). The simplified dichotomous classification of M1/M2 provides a conceptual basis for describing the polarization of macrophages and the identification of polarizing stimuli (19)(20)(21)(22)(23)(24).…”