Nerve growth factor (NGF) is a minor and neglected component of snake venom. Present study describes the purification and characterization of a NGF isoform (RVV-NGFa) from Indian Russell’s viper venom (RVV). RVV-NGFa showed a protonated molecular ion [MH+] at m/z 17388.725 Da. The RVV-NGFa induced neuritogenesis in PC-12 cells but did not show cytotoxicity in mammalian cells, hemolytic activity, platelet modulation, and interference in blood coagulation system which are the characteristic pharmacological properties of RVV. By ELISA and immunofluorescence microplate reader assay, the RVV-NGFa showed appreciable binding to TrkA receptor expressed in breast cancer MDA-MB-231 and MCF-7 cells; nevertheless, pre-incubation of cells with anti-TrkA (and not TrkB or TrkC) or anti-p⁷⁵NTR antibody significantly decreased (p < 0.05) this binding. The RVV-NGFa demonstrated insignificant binding with non-cancerous cells (HEK-293, L6) lacking TrkA receptor. The binding of RVV-NGFa to TrkA receptor of breast cancer cells resulted in internalization of ligand (RVV-NGFa)-receptor (TrkA) complex to cell cytoplasm in a time-dependent manner. The spectrofluorometric study demonstrated an interaction between RVV-NGFa and cytosolic domain of the purified TrkA receptor. The fluorescence (FITC)-tagged RVV-NGFa depicted a strong fluorescence signal that was observed under a fluorescence microscope and determined by fluorescence microplate reader assay post binding to breast cancer cells; but no fluorescence signal was detected after incubating FITC-RVV-NGFa with non-cancerous L6 and HEK-293 cells. The clinical application of FITC/fluorescence nanoparticle tagged RVV-NGFa for the ex vivo and in vivo diagnosis of breast cancer is highly promising.

神经生长因子（NGF）是蛇毒的次要且被忽略的成分。本研究描述了从印度罗素的毒蛇毒（RVV）中纯化和表征NGF同工型（RVV-NGFa）。RVV-NGFa在m / z 17388.725 Da处显示质子化的分子离子[MH +] 。RVV-NGFa诱导了PC-12细胞的神经形成，但未显示哺乳动物细胞的细胞毒性，溶血活性，血小板调节和对凝血系统的干扰，这是RVV的特征性药理特性。通过ELISA和免疫荧光酶标仪检测，RVV-NGFa与乳腺癌MDA-MB-231和MCF-7细胞中表达的TrkA受体有明显的结合。但是，将细胞与抗TrkA（而非TrkB或TrkC）或抗p⁷⁵NTR抗体显着降低（p <0.05）这种结合。RVV-NGFa与缺乏TrkA受体的非癌细胞（HEK-293，L6）结合不明显。RVV-NGFa与乳腺癌细胞的TrkA受体的结合导致配体（RVV-NGFa）-受体（TrkA）复合物以时间依赖性方式内化到细胞质中。荧光光谱研究表明，RVV-NGFa与纯化的TrkA受体的胞质域之间存在相互作用。带有荧光（FITC）标签的RVV-NGFa描绘了一个强荧光信号，该信号在荧光显微镜下观察到，并在与乳腺癌细胞结合后通过荧光酶标仪测定。但将FITC-RVV-NGFa与非癌L6和HEK-293细胞孵育后未检测到荧光信号。乳腺癌的离体和体内诊断是非常有前途的。