Role of the mechanical microenvironment on CD-44 expression of breast adenocarcinoma in response to radiotherapy

Abstract

The biological effects of ionizing radiation are exploited in the clinical practice of radiotherapy to destroy tumour cells while sparing the surrounding normal tissue. While most of the radiotherapy research focused on DNA damage and repair, recently a great attention is going to cells' interactions with the mechanical microenvironment of both malignant and healthy tissues after exposure. In fact, the stiffness of the extracellular matrix can modify cells' motility and spreading through the modulation of transmembrane proteins and surface receptors' expression, such as CD-44. CD-44 receptor has held much interest also in targeted-therapy due to its affinity with hyaluronic acid, which can be used to functionalize biodegradable nanoparticles loaded with chemotherapy drugs for targeted therapy. We evaluated changes in CD-44 expression in two mammary carcinoma cell lines (MCF10A and MDA-MB-231) after exposure to X-ray (2 or 10 Gy). To explore the role of the mechanical microenvironment, we mimicked tissues' stiffness with polyacrylamide's substrates producing two different elastic modulus values (0.5 and 15 kPa). We measured a dose dependent increase in CD-44 relative expression in tumour cells cultured in a stiffer microenvironment. These findings highlight a crucial connection between the mechanical properties of the cell's surroundings and the post-radiotherapy expression of surface receptors.

Impact of ionizing radiation on cell-ECM mechanical crosstalk in breast cancer

“…Polyacrylamide substrates were prepared following a previously published method ( Panzetta et al, 2017b ; Frascogna et al, 2024 ), with some minor adjustments. Below a step-by-step description of the pursued methodology:…”

“…Cell lines were exposed to X-rays delivered by external beam radiotherapy through the LINAC Synergy Agility system (ELEKTA), employing a 6 MV energy beam. Radiation doses of 2 and 10 Gy were delivered by 3D conformal radiation therapy (3D-CRT) treatment plans generated with the Monaco v5.11.03 treatment planning station by Elekta, as previously applied ( Panzetta et al, 2017b ; Frascogna et al, 2024 ). The selection of 2 Gy signifies the standard fractional dose commonly administered in oncological routine treatments, while 10 Gy aligns with the dosage typically employed as a post-operative boost treatment.…”

“…More recently, research on radiation-induced effects on cells has shifted to mechanobiology: nowadays the evolving interest extends beyond the survival of cancer cells to investigate the role of IR in modifying the physical interactions between cells and their surrounding microenvironment ( La Verde et al, 2021 ). Studies have highlighted how cells’ mechanical alterations are closely related to exposition doses, post-irradiation time and ECM stiffness depending on the specific cellular phenotype ( La Verde et al, 2021 ; Frascogna et al, 2024 ). Tumor cells actively perceive and react to the mechanical cues in the TME, including strength, direction, and duration.…”

“…Tumor cells actively perceive and react to the mechanical cues in the TME, including strength, direction, and duration. In the case of breast adenocarcinoma, the aggressive triple-negative MDA-MB-231 cancer cell line and their normal epithelial counterpart MCF10A, have exhibited a dose-dependent increase in adhesion when cultured on a substrate mimicking the mechanical rigidity of tumor microenvironment ( Panzetta et al, 2020 ; Frascogna et al, 2024 ). On the other hand, on physiological microenvironment both cell lines have exhibited a notable decrease in migration velocity, attributable to the existence of a potential radioprotective role related to the softer ECM ( Panzetta et al, 2015 ; Panzetta et al, 2017c ; Panzetta et al, 2019 ; Frascogna et al, 2024 ).…”

“…In the case of breast adenocarcinoma, the aggressive triple-negative MDA-MB-231 cancer cell line and their normal epithelial counterpart MCF10A, have exhibited a dose-dependent increase in adhesion when cultured on a substrate mimicking the mechanical rigidity of tumor microenvironment ( Panzetta et al, 2020 ; Frascogna et al, 2024 ). On the other hand, on physiological microenvironment both cell lines have exhibited a notable decrease in migration velocity, attributable to the existence of a potential radioprotective role related to the softer ECM ( Panzetta et al, 2015 ; Panzetta et al, 2017c ; Panzetta et al, 2019 ; Frascogna et al, 2024 ). In this last described case, only normal cells have exhibited a reduction of adhesion area proportional to the radiation absorbed dose, with MDA-MB-231 cells instead characterized by a dose dependent increase in adhesion area on the same physiological microenvironment ( Panzetta et al, 2019 ; Frascogna et al, 2024 ).…”