Charalampopoulou Alexandra, Barcellini Amelia, Ciocca Mario, Di Liberto Riccardo, Pasi Francesca, Pullia Marco Giuseppe, Orlandi Ester, Facoetti Angelica
Research and Development Department, National Center for Oncological Hadrontherapy (CNAO), Pavia, Italy.
Clinical Department, National Center for Oncological Hadrontherapy (CNAO), Pavia, Italy.
Front Oncol. 2022 Oct 12;12:1003494. doi: 10.3389/fonc.2022.1003494. eCollection 2022.
Radiotherapy represents a major treatment option for patients with pancreatic cancer, however, its benefits remain limited also due to the ability of cancer cells to migrate to the surrounding tissues. Low-LET ionizing radiation is well known to promote tumor cell migration and invasion, nevertheless, little data provided by studies using high-LET radiation has led to ambiguous findings. What is hypothesized to be fundamental in the modulation of migration of tumor cells exposed to ionizing radiation is the influence of the microenvironment. Therefore, the properties of cells that populate the tumor stroma cannot be ignored when studying the influence of radiation on the migratory and invasive capacity of cancer cells. This is especially important in the case of pancreatic malignancies that are characterized by an abundance of stromal cells, including cancer-associated fibroblasts, which are known to orchestrate the cross-talk with tumor cells.
The current study aims to investigate whether the presence of factors released by irradiated fibroblasts affects the migratory and invasive capacity of pancreatic cancer cells exposed to different doses of photons or C-ions.
AsPC-1 and AG01522 cells were irradiated with the same dose of photons or C-ions at room temperature. Through Boyden chamber assay, we tested whether factors secreted by irradiated fibroblasts may influence tumor cell migration, while the invasiveness of AsPC-1 cells was assessed using matrigel precoated inserts in which medium collected from non-irradiated (0 Gy), photon and C-ion irradiated fibroblasts, was added. Data were analyzed by Student t-test using GraphPad software. The mean ± s.d. was determined with a significance level of p<0.05.
In the presence of conditioned medium collected from 1 Gy and 2 Gy photon irradiated fibroblasts, the number of migrated tumor cells increased (P<0.0360, P<0.0001) but decreased at 4 Gy dose (P<0.002). There was a trend of reduction in migration (P<0.0460, P<0.038, P<0.0024, P<0.0002), as well as a decrease in invasiveness (P<0.0525, P<0.0035, P<0.0868, P<0.0310) after exposure to 0.5 Gy, 1 Gy, 2 Gy and 4 Gy of C-ions.
The presence of irradiated fibroblasts affected the invasiveness capability of pancreatic cancer cells, probably by the reciprocal release of soluble factors whose production is differently modulated after high or low-LET radiation. Understanding the effects of irradiation on the metastatic potential of pancreatic cancer cells is of utmost importance for improving the outcome and tailoring the therapeutic approach. This challenging scenario requires a continuous and multidisciplinary approach that involves clinicians together with researcher experts in oncological and radiation treatment. In the last years, including preclinical experiences in a multidisciplinary approach has proved to be a winning strategy in clinical oncological research.
放射治疗是胰腺癌患者的主要治疗选择之一，然而，由于癌细胞向周围组织迁移的能力，其益处仍然有限。众所周知，低线性能量传递（LET）电离辐射会促进肿瘤细胞的迁移和侵袭，不过，使用高线性能量传递辐射的研究提供的数据很少，结果也不明确。据推测，在调节暴露于电离辐射的肿瘤细胞迁移中起关键作用的是微环境的影响。因此，在研究辐射对癌细胞迁移和侵袭能力的影响时，不能忽视构成肿瘤基质的细胞特性。这在以大量基质细胞为特征的胰腺恶性肿瘤中尤为重要，这些基质细胞包括癌症相关成纤维细胞，已知它们会协调与肿瘤细胞的相互作用。
本研究旨在探讨受照射成纤维细胞释放的因子是否会影响暴露于不同剂量光子或碳离子的胰腺癌细胞的迁移和侵袭能力。
在室温下，用相同剂量的光子或碳离子照射AsPC-1和AG01522细胞。通过博伊登室试验，我们测试了受照射成纤维细胞分泌的因子是否会影响肿瘤细胞迁移，同时使用预涂基质胶的小室评估AsPC-1细胞的侵袭能力，在小室中添加从未照射（0 Gy）、光子和碳离子照射的成纤维细胞收集的培养基。使用GraphPad软件通过学生t检验分析数据。确定平均值±标准差，显著性水平为p<0.05。
在存在从1 Gy和2 Gy光子照射的成纤维细胞收集的条件培养基的情况下，迁移的肿瘤细胞数量增加（P<0.0360，P<0.0001），但在4 Gy剂量时减少（P<0.002）。暴露于0.5 Gy、1 Gy、2 Gy和4 Gy碳离子后，迁移有减少趋势（P<0.0460，P<0.038，P<0.0024，P<0.0002），侵袭性也降低（P<0.0525，P<0.0035，P<0.0868，P<0.0310）。
受照射成纤维细胞的存在影响了胰腺癌细胞的侵袭能力，可能是通过可溶性因子的相互释放，其产生在高或低LET辐射后受到不同调节。了解辐射对胰腺癌细胞转移潜能的影响对于改善治疗结果和调整治疗方法至关重要。这种具有挑战性的情况需要一种持续的多学科方法，涉及临床医生以及肿瘤学和放射治疗方面的研究专家。在过去几年中，将临床前经验纳入多学科方法已被证明是临床肿瘤学研究中的一个成功策略。
