Carolyn Klinge Ph.D.

Recipient of the LUNGevity Foundation/Joan’s Legacy Research Grant. Funded equally by Joan's Legacy and the LUNGevity Foundation.

Lay Description

The fact that women, even non-smokers, are at higher risk than men for developing a type of lung cancer called lung adenocarcinoma strongly suggests the involvement of gender-dependent factors in the etiology of lung adenocarcinoma. The overall goal of the proposed research is to determine the mechanism for this gender bias in lung adenocarcinoma. We recently published a paper showing that lung adenocarcinoma cell lines from female lung cancer patients were stimulated to replicate by estrogen and that the growth of these cells was blocked by the anti-estrogen tamoxifen, commonly used to treat women with breast cancer (1). In contrast, lung adenocarcinoma cells from male patients did not respond to estrogen or antiestrogens. These data suggest the possibility that women with lung adenocarcinoma might benefit from the use of antiestrogen therapy. In order for cells to respond to estrogen, the cells must express estrogen receptors. There are 2 types of estrogen receptors (ER) called ER? and ER?. Interestingly, although the lung adenocarcinoma cell lines from males did not respond to estrogen or ER antagonists, they expressed as much ER? and ER? as did the estrogen-responsive lung adenocarcinoma cells from females. This means that something beyond ER is different between the lung adenocarcinoma cells from women and men. Because ER? is the predominant ER in lung adenocarcinoma cell lines, our goal in the present study is to find out if the estrogen-responsive cells from females make proteins that interact with ER? that allows the cells to respond to estrogens and antiestrogens and whether lung adenocarcinoma cells from males do not express these ER?-interacting proteins. In Aim 1 we will test the hypothesis that E2 selectively increases ER? interaction with proteins that upregulate gene transcription and cell proliferation in lung adenocarcinoma cells from females but not males. In Aim 2 we will examine the expression of 2 of these proteins identified in Aim 1 in clinical lung tumor specimen from male and female patients and correlate protein expression with other measures of disease including survival. Results of these studies will tell us what proteins are differentially expressed in lung adenocarcinoma cells from women and men that could be targets of therapy to inhibit the progression of lung adenocarcinoma.

Scientific Abstract

The ~ two-fold higher risk of lung adenocarcinoma in women than in men strongly suggests the involvement of gender-dependent factors in the etiology of lung cancer (2). The overall goal of the proposed research is to determine the mechanism for this gender bias in lung adenocarcinoma. The central focus is to identify differences in the estradiol (E2)-induced proteome of lung adenocarcinoma cells from female and male origin using cutting edge bioanalytical and bioinformatic tools. We recently reported that human lung adenocarcinoma cell lines from females respond proliferatively to E2 and were inhibited by the estrogen receptor (ER) antagonists 4-hydroxytamoxifen (4-OHT) or ICI 182,780 (1). In contrast, lung adenocarcinoma cells from males were neither stimulated by E2 nor blocked by 4-OHT or ICI. Similar responses were detected in transient transfections of these cells with an estrogen response element (ERE) reporter. Despite these differences, ER? and ER? expression was similar among the cell lines from males and females, indicating that lower ER expression in cells from males is not responsible for the observed phenotype. ER? expression was greater than ER? in all lung cell lines. These results suggest that lung adenocarcinoma cells from females express proteins necessary for estrogenic responses and that cells from males express reduced levels of proteins necessary for ER activity. The proposed experiments will test the hypothesis that E2 selectively increases ER? interaction with proteins that stimulate gene transcription resulting in cell replication in lung adenocarcinoma cells from males but not females. Functional proteomics will be used to identify ER?- interacting proteins in representative female versus male lung adenocarcinoma cell lines upon E2 treatment by immunoprecipitation, SDS-PAGE, and MALDI-TOF mass spectrometry. Bioinformatic analysis of the results of this research will help to define the molecular mechanisms of estrogen action in lung adenocarcinoma. The second hypothesis to be tested is that ER?-interacting proteins that are differentially expressed in lung adenocarcinoma cell lines from males and females will show the same expression patterns in lung cancer tissue samples from female and male lung cancer patients. In the long term, our hope is that the results of these studies will identify proteins that may serve as biomarkers for the possible use of antiestrogens or aromatase inhibitors or as therapeutic targets to inhibit progression of lung adenocarcinoma in both women and men.