Through the metastatic process, cancer cells spread through the body by migrating and invading via the extracellular matrix. Photobiomodulation therapy (PBMT) on oncologic patients is controversial as it could stimulate cell proliferation and aggravate the metastatic process. Thus, this study aimed to investigate PBMT induced by low power red and infrared lasers on cell proliferation, migration and invasion and on mRNA levels from Rat sarcoma virus (RAS) oncogenes in MDA-MB-231 breast cancer cells. MDA-MB-231 cells were irradiated with low power red and infrared lasers at 25 and 50 J cm⁻², cell proliferation was evaluated using water-soluble tetrazolium salt assay, cell migration was evaluated using wound healing assay, cell invasion was performed using Matrigel transwell assay and real-time quantitative polymerase chain reaction was performed to evaluate mRNA of RAS oncogenes. Exposure to low power infrared laser could increase MDA-MB-231 cell proliferation at 25 J cm⁻². Neuroblastoma RAS oncogene (NRAS) mRNA relative levels reduced when irradiating with low power infrared at 25 J cm⁻² and for low power red laser at 50 J cm⁻². Kirsten rat sarcoma viral oncogene (KRAS) mRNA relative levels were not modified. Cell migration and invasion after exposure to low power red and infrared lasers at both fluences evaluated did not change. These results show that PBMT could modify MDA-MB-231 cell proliferation and NRAS mRNA relative levels, but no effects were found on KRAS mRNA relative levels, cell migration and invasion in both red and infrared lasers. Therefore, the screening for therapies should be tested by searching for safe conditions and herein the PBMT using red lasers altered the proliferation ratio and changed the aggressiveness phenotype of breast cancer cells.

在转移过程中，癌细胞通过细胞外基质迁移和侵入而扩散到全身。对肿瘤患者进行光生物调节疗法 (PBMT) 是有争议的，因为它可以刺激细胞增殖并加剧转移过程。因此，本研究旨在研究低功率红色和红外激光诱导的 PBMT 对细胞增殖、迁移和侵袭以及 MDA-MB-231 乳腺癌细胞中大鼠肉瘤病毒 (RAS) 癌基因的 mRNA 水平的影响。MDA-MB-231 细胞用 25 和 50 J cm ^{-2 的}低功率红光和红外激光照射，使用水溶性四唑盐试验评估细胞增殖，使用伤口愈合试验评估细胞迁移，使用 Matrigel transwell 试验进行细胞侵袭，并进行实时定量聚合酶链反应以评估 RAS 癌基因的 mRNA。暴露于低功率红外激光可以增加 25 J cm ^{-2 的}MDA-MB-231 细胞增殖。当用 25 J cm ^{-2 的}低功率红外线和 50 J cm ^{-2 的}低功率红色激光照射时，神经母细胞瘤 RAS 致癌基因 (NRAS) mRNA 的相对水平降低. Kirsten 大鼠肉瘤病毒癌基因 (KRAS) mRNA 的相对水平没有改变。暴露于低功率红色和红外激光后，评估的两种能量密度下的细胞迁移和侵袭没有变化。这些结果表明，PBMT 可以改变 MDA-MB-231 细胞增殖和 NRAS mRNA 相对水平，但在红色和红外激光中对 KRAS mRNA 相对水平、细胞迁移和侵袭没有影响。因此，应通过寻找安全条件来测试疗法的筛选，这里使用红色激光的 PBMT 改变了增殖率并改变了乳腺癌细胞的侵袭性表型。