Research

Endoplasmic reticulum Ca²⁺-homeostasis is altered in small and non-small cell lung cancer cell lines

Albrecht Bergner , Julia Kellner , Amanda Tufman and Rudolf M Huber

Division of Respiratory Medicine, Medizinische Klinik-Innenstadt, Ludwig-Maximilians-University, Munich, Germany

author email corresponding author email

Journal of Experimental & Clinical Cancer Research 2009, 28:25doi:10.1186/1756-9966-28-25

Published:	24 February 2009

Abstract

Background

Knowledge of differences in the cellular physiology of malignant and non-malignant cells is a prerequisite for the development of cancer treatments that effectively kill cancer without damaging normal cells. Calcium is a ubiquitous signal molecule that is involved in the control of proliferation and apoptosis. We aimed to investigate if the endoplasmic reticulum (ER) Ca²⁺-homeostasis is different in lung cancer and normal human bronchial epithelial (NHBE) cells.

Methods

The intracellular Ca²⁺-signaling was investigated using fluorescence microscopy and the expression of Ca²⁺-regulating proteins was assessed using Western Blot analysis.

Results

In a Small Cell Lung Cancer (H1339) and an Adeno Carcinoma Lung Cancer (HCC) cell line but not in a Squamous Cell Lung Cancer (EPLC) and a Large Cell Lung Cancer (LCLC) cell line the ER Ca²⁺-content was reduced compared to NHBE. The reduced Ca²⁺-content correlated with a reduced expression of SERCA 2 pumping calcium into the ER, an increased expression of IP₃R releasing calcium from the ER, and a reduced expression of calreticulin buffering calcium within the ER. Lowering the ER Ca²⁺-content with CPA led to increased proliferation NHBE and lung cancer cells.

Conclusion

The significant differences in Ca²⁺-homeostasis between lung cancer and NHBE cells could represent a new target for cancer treatments.