Autophagy and Oxidative Stress Defense

Autophagy and Oxidative Stress Defense

Autophagy is a principal catabolic route needed for the lysosomal degradation of damaged or excessive intracellular components.

Autophagy has at least two fundamental functions in our cells; to provide nutrients during starvation and to modulate cellular responses to extracellular insults like oxidative stress and inflammation.

Geir Bjørkøy was central for the identification of the molecular mechanisms for selective autophagy and the first autophagy cargo receptors (p62/SQSTM1 and NBR1). Since then, the group at NTNU has focused on how local signaling and metabolite levels regulate autophagy to control inflammation and tumor development.

Tumors and Autophagy

Progression of solid tumors are influenced by the local immune microenvironment. So-called immunologically “cold” tumors display clear signs of local immune suppression, develop more aggressively, and respond poorly to treatment. On the other side, immunologically “hot” tumors show favorable prognosis and better responses to therapy. We, and many others, aim to find new ways to convert the local immune environment in solid tumors from “cold” to “hot”. Autophagy can be highly selective in the degradation of intracellular proteins and organelles. Thus, autophagy has the potential to change the composition of intracellular signaling proteins in cancer and immune cells as well as other cells within and outside tumors. Activation of the Type I interferon response is a sign of a “hot” tumor. We have published that autophagy coincide with a dampening of the Type I interferon response in innate immune cells. We now study if immune reactions within solid tumors is controlled by autophagy. For these studies, we combine data from tumors from an immunocompetent mouse model with data mining in large databases of tumor biopsy and clinical information. The aim is to explore the idea that autophagy is a selective cellular mechanism that controls tumor immunity.

Innate immune cells like macrophages and neutrophils are important in solid tumors to orchestrate if the microenvironment is “hot” or “cold”. Tumors dominated by anti-inflammatory macrophages indicate poor prognosis and limited effect of therapy. Formation of such macrophages depends on the macrophage specific receptor CSF1R. In a multidisciplinary collaboration, we are screening novel CSF1R inhibitors designed and synthesized by our collaborators at NTNU. The novel compounds are monitored for effects on macrophages in culture, tumors, and tissues. The aim of these studies is to find different ways to target innate immune cells and reprogram the local immune microenvironment.

Autophagy, tumor immunity and oxidative stress defense

We also study the interplay between autophagy, tumor immunity and the oxidative stress defense controlled by the transcriptional regulator NRF2. Particularly, we have investigated the role of NRF2-driven transcription in metastatic breast cancer development in mice and humans. This have resulted in the identification of an NRF2-driven gene expression signature in RNA isolated from breast cancer biopsies. The signature is a strong and independent predictor for poor prognosis and has the potential to improve personalized breast cancer treatment.

Autophagy is a core process to mobilize nutrients during starvation. The proliferation of the cancer cells in solid tumors is restricted by the availability of nutrients and oxygen. Many cancer patients develop severe loss of body mass in the terminal phase of the disease. This detrimental complication has been named cancer cachexia and involve severe loss of muscle proteins. It has for long been assumed that the induced catabolism is due to signaling compounds released from the tumor that induce a systemic protein degradation, particularly in muscle cells. However, the identity of such compounds is not completely clear and it is still unknown how the cells induce protein degradation.

We have found that serum from cancer patients contain autophagy-inducing bioactivity and that this activity associates with loss in body weight. Our data demonstrate that IL-6 secreted from cancer cells induce responses in muscle cells when complexed to soluble IL-6 receptor. We have recently uncovered how TGF-related signaling inside tumors controls IL-6 secretion from the cancer cells and weight loss in tumor-bearing mice. We are now studying the interplay between cancer cells, innate immune cells and muscle cells that leads to severe protein degradation and muscle atrophy in cachexia patients. The aim is to find novel therapeutic ways to block this detrimental route for feeding the cancer cell growth.


The group collaborate closely with other groups at CEMIR, NTNU, St. Olavs Hospital and SINTEF. We also collaborate with Professor Terje Johansen at the University of Tromsø and Dr. Carsten Jacobi at Novartis, Basel, on aspects of autophagy and cachexia. For novel compounds targeting macrophage activities, we collaborate with Dr. Clare Pridans at the University of Edinburgh and the Max Planck Lead Drug Discovery Center in Dortmund with manager Dr. Bert Klebel.

25 Jun 2021 Irene Aspli

Research Documentation

Research Documentation

Research documentation, Geir Bjørkøy

  1. Kristine Pettersen, Sonja Andersen, Simone Degen, Valentina Tadini, Joël Grosjean, Shinji Hatakeyama, Almaz N. Tesfahun, Siver Moestue, Jana Kim, Unni Nonstad, Pål R. Romundstad, Frank Skorpen, Sveinung Sørhaug, Tore Amundsen, Bjørn H. Grønberg, Florian Strasser, Nathan Stephens, Dag Hoem, Anders Molven, Stein Kaasa, Kenneth Fearon,  Carsten Jacobi, Geir Bjørkøy. Tumor-derived IL-6 induces autophagy via trans-signaling and may promote cachexia in cancer patients. Scientific Reports  (impact factor 5,23). Accepted | Cancer cachexia associates with a systemic autophagy-inducing activity mimicked by cancer cell-derived IL-6 trans-signaling​​​​​​​
  2. Jennifer Mildenberger, Ida Johansson, Eli Kjøbli, Jan Kristian Damås, Trude Helen Flo and Geir Bjørkøy. N-3 PUFAs induce inflammatory tolerance by formation of KEAP1 containing p62-bodies. Autophagy (impact factor 11,75). In revision for resubmission.
  3. Katarzyna Baranowska, Kristine Misund, Kristian K. Starheim, Toril Holien1, Ida Johansson, Sagar Darvekar, Glenn Buene, Anders Waage, Geir Bjørkøy and Anders Sundan (2016). Hydroxychloroquine potentiates carfilzomib toxicity towards myeloma cells. Oncotarget. 7(43):70845-70856 (impact factor 6,36)
  4. Kristian K. Starheim, Toril Holien, Kristine Misund, Ida Johansson, Katarzyna A. Baranowska, Anne-Marit Sponaas, Hanne Hella, Glenn Buene, Anders Waage, Anders Sundan, Geir Bjørkøy (2016). Intracellular glutathione determines bortezomib cytotoxicity in multiple myeloma cells. Blood Cancer Journal. 6(7):e446 (impact factor 4,44)
  5. Pettersen K, Monsen VT, Hakvåg Pettersen CH, Overland HB, Pettersen G, Samdal H, Tesfahun AN, Lundemo AG, Bjørkøy G*, Schønberg SA*. (2016) DHA-induced stress response in human colon cancer cells - Focus on oxidative stress and autophagy. Free Radic Biol Med. 90:158-72 (impact factor 5,7) *) shared senior authors
  6. Ida Johansson, Vivi Talstad Monsen, Kristine Pettersen, Jennifer Mildenberger, Kristine Misund, Kai Kaarniranta, Svanhild Schønberg and Geir Bjørkøy (2015). The marine n-3 PUFA DHA evokes cytoprotection against oxidative stress and protein misfolding by inducing autophagy and NFE2L2  in human retinal pigment epithelial cells. Autophagy. 11(9):1636-51 (impact factor 11,4).
  7. Siver A. Moestue, Cornelia G. Dam, Saurabh Gorad, Alexandr Kristian, Anna Bofin, Gunhild M. Mælandsmo, Olav Engebråten, Ingrid S. Gribbestad, Geir Bjørkøy (2013). Metabolic biomarkers for response to PI3K inhibition in basal-like breast cancer. Breast Cancer Res. 15(1):R16. (impact factor 5,9)
  8. Serhyi Pankiv, Endalkachew A. Alemu, Andreas Brech, Jack-Ansgar Bruun, Trond Lamark, Aud Øvervatn, Geir Bjørkøy and Terje Johansen (2010) FYCO1 is a novel Rab7 effector binding to MAP1-LC3 and PI3P to mediate microtubule plus-end-directed vesicle transport. Journal of Cell Biology. 188(2):253-69. (impact factor 9,8)
  9. Pankiv S, Clausen TH, Lamark T, Brech A, Bruun JA, Outzen H, Øvervatn A, Bjørkøy G, Johansen T. (2007) p62/SQSTM1 binds directly to Atg8/LC3 to facilitate degradation of ubiquitinated protein aggregates by autophagy. J Biol Chem. 282(33):24131-45 (impact factor 4,6)
  10. Bjørkøy G, Lamark T, Brech A, Outzen H, Perander M, Overvatn A, Stenmark H, Johansen T. (2005). p62/SQSTM1 forms protein aggregates degraded by autophagy and has a protective effect on huntingtin-induced cell death. J Cell Biol. 171(4):603-14 (impact factor 9,8)

Publications by Geir Bjørkøy - PubMed 

"bjorkoy G[Author] OR Bjorkoy, Geir[Full Author Name]"


Group Leader

Kristine Pettersen



Carsten Jacobi, Researcher. Novartis, Basel, Switzerland

Terje Johansen, Professor, UiT The Arctic university of Norway

Bert Klebel, Manager, Max Planck Lead Drug Discovery Center, Dortmund, Germany

Clare Pridans, Researcher, University of Edinburgh, UK