ProMetTre scientists have made a breakthrough discovery in cancer research by identifying a novel protein in breast cancer that is affected by cell stress and is not present in normal breast cells.
Our research shows a link between molecular stress, how a cancer can spread (metastasise) and the development of drug resistance. We are working to translate our findings to improve the prognosis for cancer patients.
Discovery of a new protein in breast cancer that is influenced by growth signalling and cell stress
BACKGROUND
The EGR4 protein plays an important role in the proliferation of small cell lung cancer.

Our research identified a new, shortened version of this protein found in breast cancer cells, we named it EGR4-S

RESULTS
1. Treating breast cancer cells with drugs that block growth signalling reduced EGR4-S expression
2. However, sustained, high-dose treatment led to less repression of EGR4-S

3. We also identified an inverse relationship between cell stress and EGR4-S

Cell stress suppresses
growth rate BUT enhanced properties associated with metastatic potential
WHAT’S NEXT?
RESEARCH ON STRESS IN CANCER
Chronic stress has been demonstrated in mouse models to promote cancer metastasis [1, 2]. More acutely, stress hormones that circulate in the body, such as adrenaline and noradrenaline, directly promote malignant features of cancer in vitro [3-10]. Additionally, we know cortisol and other glucocorticoids promote tumour growth [11, 12] and that breast cancer patients with higher tumour expression of glucocorticoid receptors have a worse prognosis than those with lower glucocorticoid receptor expression [13, 14].
At the cellular level, stress also has an association with advanced disease, drug resistance and metastasis in many types of cancer [15-17]. One response to cellular stress, called the heat shock response, is triggered by many forms of stress including heat, chemicals and infections, where the response acts to maintain intracellular protein homeostasis and protect the cell against stress-induced death [18].
As part of the heat shock response to cell stress, there is an accumulation of heat shock proteins (HSPs) within the cell [19, 20]. Increased expression of HSPs is frequently observed in several types of solid tumours [21] with stressful features in the tumour microenvironment (such as low oxygen, low glucose and acidosis) leading to this HSP induction [22, 23]. As a cancer progresses, the expression of HSPs appears to increase concurrently and, consistent with this, many high grade tumours have highly elevated HSP expression. Specifically, high levels of HSPs have all been shown to support various tumourigenic properties including enhanced cancer cell invasion, metastasis and capacity for survival, and their increased expression frequently correlates with poor patient response to therapy and worse patient prognosis in terms of overall survival [24, 25]. Recent evidence from 500 patients with metastatic solid tumours revealed a global increase in stress response compared to normal tissues [26].
The ‘master regulator’ of the heat shock response is the transcription factor Heat Shock Factor 1 (HSF1) which is activated when a cell is under stress [20, 27]. HSF1 has long been reported to play crucial roles in cancer progression, metastasis and drug resistance [27, 28]. This cell stress response is part of the focus of our research.
SUGGESTED further reading:
Eckerling et al. (2021) – https://doi.org/10.1038/s41568-021-00395-5
Falcinelli et al. (2021) – https://doi.org/10.1158/0008-5472.CAN-21-0684
REFERENCES
- Sloan, E.K., et al., The sympathetic nervous system induces a metastatic switch in primary breast cancer. Cancer Res, 2010. 70(18): p. 7042-52 DOI: 10.1158/0008-5472.CAN-10-0522.
- Du, P., et al., Chronic stress promotes EMT-mediated metastasis through activation of STAT3 signaling pathway by miR-337-3p in breast cancer. Cell Death Dis, 2020. 11(9): p. 761 DOI: 10.1038/s41419-020-02981-1.
- Liu, J., et al., A novel beta2-AR/YB-1/beta-catenin axis mediates chronic stress-associated metastasis in hepatocellular carcinoma. Oncogenesis, 2020. 9(9): p. 84 DOI: 10.1038/s41389-020-00268-w.
- Nagaraja, A.S., et al., Sustained adrenergic signaling leads to increased metastasis in ovarian cancer via increased PGE2 synthesis. Oncogene, 2016. 35(18): p. 2390-7 DOI: 10.1038/onc.2015.302.
- Wong, H.P., et al., Effects of adrenaline in human colon adenocarcinoma HT-29 cells. Life Sci, 2011. 88(25-26): p. 1108-12 DOI: 10.1016/j.lfs.2011.04.007.
- Kim-Fuchs, C., et al., Chronic stress accelerates pancreatic cancer growth and invasion: a critical role for beta-adrenergic signaling in the pancreatic microenvironment. Brain Behav Immun, 2014. 40: p. 40-7 DOI: 10.1016/j.bbi.2014.02.019.
- Pu, J., et al., Adrenaline promotes epithelial-to-mesenchymal transition via HuR-TGFbeta regulatory axis in pancreatic cancer cells and the implication in cancer prognosis. Biochem Biophys Res Commun, 2017. 493(3): p. 1273-1279 DOI: 10.1016/j.bbrc.2017.09.146.
- Sood, A.K., et al., Adrenergic modulation of focal adhesion kinase protects human ovarian cancer cells from anoikis. J Clin Invest, 2010. 120(5): p. 1515-23 DOI: 10.1172/JCI40802.
- Zhang, X., et al., Chronic stress promotes gastric cancer progression and metastasis: an essential role for ADRB2. Cell Death Dis, 2019. 10(11): p. 788 DOI: 10.1038/s41419-019-2030-2.
- Zhi, X., et al., Adrenergic modulation of AMPKdependent autophagy by chronic stress enhances cell proliferation and survival in gastric cancer. Int J Oncol, 2019. 54(5): p. 1625-1638 DOI: 10.3892/ijo.2019.4753.
- Feng, Z., et al., Chronic restraint stress attenuates p53 function and promotes tumorigenesis. Proc Natl Acad Sci U S A, 2012. 109(18): p. 7013-8 DOI: 10.1073/pnas.1203930109.
- Yang, H., et al., Stress-glucocorticoid-TSC22D3 axis compromises therapy-induced antitumor immunity. Nat Med, 2019. 25(9): p. 1428-1441 DOI: 10.1038/s41591-019-0566-4.
- Obradovic, M.M.S., et al., Glucocorticoids promote breast cancer metastasis. Nature, 2019. 567(7749): p. 540-544 DOI: 10.1038/s41586-019-1019-4.
- Pan, D., M. Kocherginsky, and S.D. Conzen, Activation of the glucocorticoid receptor is associated with poor prognosis in estrogen receptor-negative breast cancer. Cancer Res, 2011. 71(20): p. 6360-70 DOI: 10.1158/0008-5472.CAN-11-0362.
- Mazurov, V.V., et al., Small heat shock protein hsp27 as a possible mediator of intercellular adhesion-induced drug resistance in human larynx carcinoma HEp-2 cells. Biosci Rep, 2003. 23(4): p. 187-97 DOI: 10.1023/b:bire.0000007692.59551.d8.
- Morii, T., et al., Inhibition of heat-shock protein 27 expression eliminates drug resistance of osteosarcoma to zoledronic acid. Anticancer Res, 2010. 30(9): p. 3565-71.
- Oesterreich, S., et al., The small heat shock protein hsp27 is correlated with growth and drug resistance in human breast cancer cell lines. Cancer Res, 1993. 53(19): p. 4443-8.
- Lindquist, S. and E.A. Craig, The heat-shock proteins. Annu Rev Genet, 1988. 22: p. 631-77 DOI: 10.1146/annurev.ge.22.120188.003215.
- Lang, B.J., et al., The functions and regulation of heat shock proteins; key orchestrators of proteostasis and the heat shock response. Arch Toxicol, 2021. 95(6): p. 1943-1970 DOI: 10.1007/s00204-021-03070-8.
- Lindquist, S., The heat-shock response. Annu Rev Biochem, 1986. 55: p. 1151-91 DOI: 10.1146/annurev.bi.55.070186.005443.
- Ciocca, D.R. and S.K. Calderwood, Heat shock proteins in cancer: diagnostic, prognostic, predictive, and treatment implications. Cell Stress Chaperones, 2005. 10(2): p. 86-103 DOI: 10.1379/csc-99r.1.
- Calderwood, S.K., Heat shock proteins in breast cancer progression–a suitable case for treatment? Int J Hyperthermia, 2010. 26(7): p. 681-5 DOI: 10.3109/02656736.2010.490254.
- Witkin, S.S., Heat shock protein expression and immunity: relevance to gynecologic oncology. Eur J Gynaecol Oncol, 2001. 22(4): p. 249-56.
- Calderwood, S.K., et al., Heat shock proteins in cancer: chaperones of tumorigenesis. Trends Biochem Sci, 2006. 31(3): p. 164-72 DOI: 10.1016/j.tibs.2006.01.006.
- Lang, B.J., et al., Heat Shock Proteins Are Essential Components in Transformation and Tumor Progression: Cancer Cell Intrinsic Pathways and Beyond. Int J Mol Sci, 2019. 20(18) DOI: 10.3390/ijms20184507.
- Robinson, D.R., et al., Integrative clinical genomics of metastatic cancer. Nature, 2017. 548(7667): p. 297-303 DOI: 10.1038/nature23306.
- Prince, T.L., et al., HSF1: Primary Factor in Molecular Chaperone Expression and a Major Contributor to Cancer Morbidity. Cells, 2020. 9(4) DOI: 10.3390/cells9041046.
- Alasady, M.J. and M.L. Mendillo, The Multifaceted Role of HSF1 in Tumorigenesis. Adv Exp Med Biol, 2020. 1243: p. 69-85 DOI: 10.1007/978-3-030-40204-4_5.