Stanniocalcin-2 (STC2): A potential lung cancer biomarker promotes lung cancer metastasis and progression.

The homodimeric glycoprotein, stanniocalcin 2 (STC2) is previously known to be involved in the regulation of calcium and phosphate transport in the kidney and also reported to play multiple roles in several cancers. However, its function and clinical significance in lung cancer have never been reported and still remain uncertain. Here, we investigated the possibility of STC2 as a lung cancer biomarker and identified its potential role in lung cancer cell growth, metastasis and progression. Proteomic analysis of secretome of primary cultured lung cancer cells revealed higher expression of STC2 in cancers compared to that of adjacent normal cells. RT-PCR and Western blot analyses showed higher mRNA and protein expressions of STC2 in lung cancer tissues compared to the adjacent normal tissues. Knockdown of STC2 in H460 lung cancer cells slowed down cell growth progression and colony formation. Further analysis revealed suppression of migration, invasion and delayed G0/G1 cell cycle progression in the STC2 knockdown cells. STC2 knockdown also attenuated the H202-induced oxidative stress on H460 cell viability with a subsequent increase in intracellular ROS levels, which suggest a protective role of STC2 in redox regulatory system of lung cancer. These findings suggest that STC2 can be a potential lung cancer biomarker and plays a positive role in lung cancer metastasis and progression. This article is part of a Special Issue entitled: Medical Proteomics.