Su Qu

• Sikkeland, Jørgen; Ng, Matthew; Nenseth, Hatice Zeynep; Ünal, Bilal; Qu, Su & Jin, Yang [Show all 8 contributors for this article] (2022). STAMP2 suppresses autophagy in prostate cancer cells by modulating the integrated stress response pathway. American Journal of Cancer Research. 12(1), p. 327–336. Full text in Research Archive Show summary

  Six Transmembrane Protein of Prostate 2 (STAMP2) is critical for prostate cancer (PCa) growth. We previously showed that STAMP2 regulates the expression of stress induced transcription factor ATF4, which is implicated in starvation-induced autophagy. We therefore investigated whether STAMP2 is involved in the regulation of autophagy in PCa cells. Here we show that STAMP2 suppresses autophagy in PCa cells through modulation of the integrated stress response axis. We also find that STAMP2 regulates mitochondrial respiration. These findings suggest that STAMP2 has significant metabolic effects through mitochondrial function and autophagy, both of which support PCa growth.

• Sikkeland, Jørgen; Lindstad, Torstein; Nenseth, Hatice Zeynep; Dezitter, Xavier Gabriel M; Qu, Su & Muhumed, Ridhwan Mohamed [Show all 9 contributors for this article] (2019). Inflammation and ER stress differentially regulate STAMP2 expression and localization in adipocytes. Metabolism: Clinical and Experimental. ISSN 0026-0495. 93, p. 75–85. doi: 10.1016/j.metabol.2019.01.014. Full text in Research Archive Show summary

  Background Chronic ER stress and dysfunction is a hallmark of obesity and a critical contributor to metaflammation, abnormal hormone action and altered substrate metabolism in metabolic tissues, such as liver and adipocytes. Lack of STAMP2 in lean mice induces inflammation and insulin resistance on a regular diet, and it is dysregulated in the adipose tissue of obese mice and humans. We hypothesized that the regulation of STAMP2 is disrupted by ER stress. Methods 3T3-L1 and MEF adipocytes were treated with ER stress inducers thapsigargin and tunicamycin, and inflammation inducer TNFα. The treatments effect on STAMP2 expression and enzymatic function was assessed. In addition, 3T3-L1 adipocytes and HEK cells were utilized for Stamp2 promoter activity investigation performed with luciferase and ChIP assays. Results ER stress significantly reduced both STAMP2 mRNA and protein expression in cultured adipocytes whereas TNFα had the opposite effect. Concomitant with loss of STAMP2 expression during ER stress, intracellular localization of STAMP2 was altered and total iron reductase activity was reduced. Stamp2 promoter analysis by reporter assays and chromatin immunoprecipitation, showed that induction of ER stress disrupts C/EBPα-mediated STAMP2 expression. Conclusion These data suggest a clear link between ER stress and quantitative and functional STAMP2-deficiency.

• Sheng, Xia; Nenseth, Hatice Zeynep; Qu, Su; Kuzu, Ömer Faruk; Frahnow, Turid & Simon, Lukas [Show all 16 contributors for this article] (2019). IRE1α-XBP1s pathway promotes prostate cancer by activating c-MYC signaling. Nature Communications. 10:323, p. 1–12. doi: 10.1038/s41467-018-08152-3. Full text in Research Archive Show summary

  Activation of endoplasmic reticulum (ER) stress/the unfolded protein response (UPR) has been linked to cancer, but the molecular mechanisms are poorly understood and there is a paucity of reagents to translate this for cancer therapy. Here, we report that an IRE1α RNase-specific inhibitor, MKC8866, strongly inhibits prostate cancer (PCa) tumor growth as monotherapy in multiple preclinical models in mice and shows synergistic antitumor effects with current PCa drugs. Interestingly, global transcriptomic analysis reveal that IRE1α-XBP1s pathway activity is required for c-MYC signaling, one of the most highly activated oncogenic pathways in PCa. XBP1s is necessary for optimal c-MYC mRNA and protein expression, establishing, for the first time, a direct link between UPR and oncogene activation. In addition, an XBP1-specific gene expression signature is strongly associated with PCa prognosis. Our data establish IRE1α-XBP1s signaling as a central pathway in PCa and indicate that its targeting may offer novel treatment strategies.

• Lindstad, Torstein; Qu, Su; Sikkeland, Jørgen; Jin, Yang; Kristian, Alexandr & Mælandsmo, Gunhild [Show all 8 contributors for this article] (2016). STAMP2 is required for human adipose-derived stem cell differentiation and adiposite-facilitated prostrate cancer grown in vivo. OncoTarget. 8(54), p. 91817–91827. doi: 10.18632/oncotarget.11131. Full text in Research Archive
• Jin, Yang; Ling, Wang; Qu, Su; Sheng, Xia; Kristian, Alexandr & Mælandsmo, Gunhild [Show all 20 contributors for this article] (2015). STAMP2 increases oxidative stress and is critical for prostate cancer. EMBO Molecular Medicine. ISSN 1757-4676. 7(3), p. 315–331. doi: 10.15252/emmm.201404181. Full text in Research Archive Show summary

  The six transmembrane protein of prostate 2 (STAMP2) is an androgen‐regulated gene whose mRNA expression is increased in prostate cancer (PCa). Here, we show that STAMP2 protein expression is increased in human PCa compared with benign prostate that is also correlated with tumor grade and treatment response. We also show that STAMP2 significantly increased reactive oxygen species (ROS) in PCa cells through its iron reductase activity which also depleted NADPH levels. Knockdown of STAMP2 expression in PCa cells inhibited proliferation, colony formation, and anchorage‐independent growth, and significantly increased apoptosis. Furthermore, STAMP2 effects were, at least in part, mediated by activating transcription factor 4 (ATF4), whose expression is regulated by ROS. Consistent with in vitro findings, silencing STAMP2 significantly inhibited PCa xenograft growth in mice. Finally, therapeutic silencing of STAMP2 by systemically administered nanoliposomal siRNA profoundly inhibited tumor growth in two established preclinical PCa models in mice. These data suggest that STAMP2 is required for PCa progression and thus may serve as a novel therapeutic target.

• Qu, Su; Olafsrud, Solveig Mjelstad; Meza-Zepeda, Leonardo Andrés & Saatcioglu, Fahri (2013). Rapid Gene Expression Changes in Peripheral Blood Lymphocytes upon Practice of a Comprehensive Yoga Program. PLOS ONE. 8(4). doi: 10.1371/journal.pone.0061910. Full text in Research Archive
• Jin, Yang; Qu, Su; Tesikova, Martina; Ling, Wang; Kristian, Alexandr & Mælandsmo, Gunhild [Show all 19 contributors for this article] (2013). Molecular circuit involving KLK4 integrates androgen and mTOR signaling in prostate cancer. Proceedings of the National Academy of Sciences of the United States of America (PNAS). ISSN 0027-8424. 110(28), p. E2572–E2581. doi: 10.1073/pnas.1304318110. Full text in Research Archive
• Kaarbø, Mari; Storm, Margrethe; Qu, Su; Wæhre, Haakon; Risberg, Bjørn Åke & Danielsen, Håvard Emil [Show all 7 contributors for this article] (2013). TCTP is an androgen-regulated gene implicated in prostate cancer. PLOS ONE. 8(7:e69398). doi: 10.1371/journal.pone.0069398. Full text in Research Archive Show summary

  TCTP has been implicated in a plethora of important cellular processes related to cell growth, cell cycle progression, malignant transformation and inhibition of apoptosis. In addition to these intracellular functions, TCTP has extracellular functions and plays an important role in immune cells. TCTP expression was previously shown to be deregulated in prostate cancer, but its function in prostate cancer cells is largely unknown. Here we show that TCTP expression is regulated by androgens in LNCaP prostate cancer cells in vitro as well as human prostate cancer xenografts in vivo. Knockdown of TCTP reduced colony formation and increased apoptosis in LNCaP cells, implicating it as an important factor for prostate cancer cell growth. Global gene expression profiling in TCTP knockdown LNCaP cells showed that several interferon regulated genes are regulated by TCTP, suggesting that it may have a role in regulating immune function in prostate cancer. In addition, recombinant TCTP treatment increased colony formation in LNCaP cells suggesting that secreted TCTP may function as a proliferative factor in prostate cancer. These results suggest that TCTP may have a role in prostate cancer development. Copyright: © 2013 Kaarbø et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License.

• Kaarbø, Mari; Mikkelsen, Øyvind Løveseter; Malerød, Lene; Qu, Su; Lobert, Viola & Akgul, Gulcan [Show all 9 contributors for this article] (2010). PI3K-AKT-mTOR pathway is dominant over androgen receptor signaling in prostate cancer cells. Cellular Oncology. ISSN 1570-5870. 32(1-2), p. 11–27. doi: 10.3233/CLO-2009-0487. Full text in Research Archive
• Kaarbø, Mari; Mikkelsen, Øyvind Løveseter; Malerød, Lene; Qu, Su; Lobert, Viola & Akgul, Gulcan [Show all 9 contributors for this article] (2010). PI3K-AKT-mTOR pathway is dominant over androgen receptor signaling in prostate cancer cells. Analytical Cellular Pathology. ISSN 2210-7177. doi: 10.3233/CLO-2009-0487. Full text in Research Archive
• Lindstad, Torstein; Jin, Yang; Ling, Wang; Qu, Su & Saatcioglu, Fahri (2010). STAMPs at the Crossroads of Cancer and Nutrition. Nutrition and Cancer. ISSN 0163-5581. 62(7), p. 891–895. doi: 10.1080/01635581.2010.509836. Full text in Research Archive
• Ling, Wang; Jin, Yang; Arnoldussen, Yke Jildouw; Jonson, Ida; Qu, Su & Mælandsmo, Gunhild [Show all 11 contributors for this article] (2010). STAMP1 Is Both a Proliferative and an Antiapoptotic Factor in Prostate Cancer. Cancer Research. ISSN 0008-5472. 70(14), p. 5818–5828. doi: 10.1158/0008-5472.CAN-09-4697. Full text in Research Archive

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• Sheng, Xia; Nenseth, Hatice Zeynep; Qu, Su; Kuzu, Omer; Frahnow, Turid & Simon, Lukas [Show all 16 contributors for this article] (2024). Correction to: IRE1α-XBP1s pathway promotes prostate cancer by activating c-MYC signaling (Nature Communications, (2019), 10, 1, (323), 10.1038/s41467-018-08152-3). Nature Communications. 15(1). doi: 10.1038/s41467-024-50645-x. Full text in Research Archive
• Storm, Margrethe; Kaarbo, Mari; Qu, Su; Wæhre, Haakon; Risberg, Bjørn Åke & Danielsen, Håkon [Show all 7 contributors for this article] (2013). TCTP is Androgen-Regulated and Over-Expressed in Prostate Cancer. The FASEB Journal. ISSN 0892-6638. 27. Full text in Research Archive

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