Physics Department, SUNY University at Albany, 1400, Washington Avenue, Albany, NY, USA.
Department of Molecular and Cellular Physiology, Albany Medical College, 47 New Scotland Avenue, Albany, NY, 12208, USA.
Redox Biol. 2020 Sep;36:101617. doi: 10.1016/j.redox.2020.101617. Epub 2020 Jun 24.
Transferrin (Tf) is an essential serum protein which delivers iron throughout the body via transferrin-receptor (TfR)-mediated uptake and iron release in early endosomes. Currently, there is no robust method to assay the population of iron-bound Tf in intact cells and tissues. Raman hyperspectral imaging detected spectral peaks that correlated with iron-bound Tf in intact cells and tumor xenografts sections (~1270-1300 cm). Iron-bound (holo) and iron-free (apo) human Tf forms were endocytosed by MDAMB231 and T47D human breast cancer cells. The Raman iron-bound Tf peak was identified in cells treated with holo-Tf, but not in cells incubated with apo-Tf. A reduction in the Raman peak intensity between 5 and 30 min of Tf internalization was observed in T47D, but not in MDAMB231, suggesting that T47D can release iron from Tf more efficiently than MDAMB231. MDAMB231 may display a disrupted iron homeostasis due to iron release delays caused by alterations in the pH or ionic milieu of the early endosomes. In summary, we have demonstrated that Raman hyperspectral imaging can be used to identify iron-bound Tf in cell cultures and tumor xenografts and detect iron release behavior of Tf in breast cancer cells.
转铁蛋白（Tf）是一种重要的血清蛋白，通过转铁蛋白受体（TfR）介导的摄取和早期内涵体中的铁释放，将铁输送到全身。目前，尚无稳健的方法来检测完整细胞和组织中铁结合 Tf 的群体。拉曼高光谱成像检测到与完整细胞和肿瘤异种移植切片中的铁结合 Tf 相关的光谱峰（约 1270-1300 cm）。铁结合（全）和无铁（脱）人 Tf 形式被 MDAMB231 和 T47D 人乳腺癌细胞内吞。在用全 Tf 处理的细胞中鉴定出拉曼铁结合 Tf 峰，但在用脱 Tf 孵育的细胞中未鉴定出该峰。在 T47D 中观察到 Tf 内化 5-30 分钟内拉曼峰强度降低，但在 MDAMB231 中未观察到，这表明 T47D 比 MDAMB231 更有效地从 Tf 中释放铁。MDAMB231 可能由于早期内涵体的 pH 或离子环境改变导致铁释放延迟而表现出铁稳态失调。总之，我们已经证明，拉曼高光谱成像可用于识别细胞培养物和肿瘤异种移植中的铁结合 Tf，并检测乳腺癌细胞中 Tf 的铁释放行为。
