Publikasjoner
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Yadav, Ajay; Richartz, Nina; Bhagwat, Sampada; Burman, Marta Maria; Munthe-Kaas, Monica Cheng & Skålhegg, Bjørn Steen
[Vis alle 9 forfattere av denne artikkelen]
(2026).
Starvation of leukemic cells enhances DNA damage-induced apoptosis in vitro via ROS/p38 MAPK and prevents leukemia progression in fasting xenograft mice.
Journal of Biological Chemistry.
ISSN 0021-9258.
302(3).
doi:
10.1016/j.jbc.2026.111143.
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Most children with acute lymphoblastic leukemia (ALL) achieve long-term survival due to intensive multimodal chemotherapy. However, the use of cytotoxic DNA-damaging agents is frequently associated with severe long-term side effects, prompting continued efforts to improve treatment strategies. This study explores the potential of starving the leukemic cells to enhance the efficacy of DNA-damaging therapy in ALL. Previous work demonstrated that cAMP signaling attenuates DNA damage-induced apoptosis in ALL cells, both in vitro and in a xenograft model. The current findings show that glucose and serum deprivation reverse the effect of cAMP, converting it from a survival factor to a promoter of DNA damage-induced apoptosis in ALL-derived cell lines and patient-derived leukemic cells in vitro. The starvation-induced sensitization was independent of p53 but was shown to require increased levels of reactive oxygen species (ROS). In turn, the elevated ROS levels enhanced the activation of the mitogen-activated protein kinase p38 (p38 MAPK). The resulting augmented cell death was inhibited both by the ROS scavenger N-acetyl cysteine and the p38 MAPK inhibitor SB 202190. The translational potential of increasing the efficacy of DNA damaging agents in starving ALL cells was supported by in vivo data showing that intermittent fasting, combined with subtherapeutic doses of irradiation, significantly inhibits the leukemia progression in a xenograft model of severe combined immunodeficiency mice.
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Matar, Sittana Babiker Hassan; Skah, Seham; Diomande, Liza Eleen; Buss, Tim; Hagland, Hanne Røland & Yadav, Ajay
[Vis alle 11 forfattere av denne artikkelen]
(2025).
Development of a Novel Bifunctional Anti-CD47 Fusion Protein with Improved Efficacy and a Favorable Safety Profile.
Molecular Cancer Therapeutics.
ISSN 1535-7163.
24(6),
s. 816–827.
doi:
10.1158/1535-7163.MCT-24-0917.
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Therapeutic anti-CD47 monoclonal antibodies (mAbs) are designed to block the CD47–SIRPα checkpoint and promote immune-mediated recognition and elimination of cancer cells. However, current anti-CD47 mAbs have limitations, including off-tumor toxicity and reduced effectiveness in advanced cancers. Additionally, CD47 serves as a death receptor that mediates programmed cancer cell death (PCCD), a mechanism that has not been fully explored in current therapies. In this study, we introduce CO-001, a chimeric bifunctional IgG4 mAb, and its optimized variant CO-005, a bivalent humanized single-chain fragment variable–fragment crystallizable fusion protein. Both CO-001 and CO-005 promoted phagocytosis and PCCD. CO-005, specifically engineered to overcome the safety limitations associated with anti-CD47 antibodies, demonstrates a superior hematologic safety profile in vitro and ex vivo compared with benchmark anti-CD47 antibodies. Notably, CO-005 exhibited no binding to red blood cells, limited binding to white blood cells, and showed no hemagglutination activity. In preclinical models, CO-005 demonstrated potent antitumor activity in B-cell precursor acute lymphoblastic leukemia and Raji lymphoma xenograft models through the dual action of PCCD induction and enhancement of phagocytosis. The ability of CO-005 to trigger strong PCCD while preserving conventional immune responses provides a novel and promising approach for CD47-targeted cancer therapy. Its favorable safety profile, observed in both in vitro and ex vivo studies, positions CO-005 as a promising candidate with potential therapeutic advantages over existing anti-CD47 treatments.
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Richartz, Nina; Pietka, Wojciech; Yadav, Ajay; Bostad, Monica; Bhagwat, Sampada & Naderi, Soheil
[Vis alle 10 forfattere av denne artikkelen]
(2023).
N-acetyl cysteine turns EPAC activators into potent killers of acute lymphoblastic leukemia cells.
Journal of Biological Chemistry.
ISSN 0021-9258.
300(1).
doi:
10.1016/j.jbc.2023.105509.
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Today, the majority of patients with pediatric B cell precursor acute lymphoblastic leukemia (BCP-ALL, hereafter ALL) survive their disease, but many of the survivors suffer from life-limiting late effects of the treatment. ALL develops in the bone marrow, where the cells are exposed to cAMP-generating prostaglandin E2. We have previously identified the cAMP signaling pathway as a putative target for improved efficacy of ALL treatment, based on the ability of cAMP signaling to reduce apoptosis induced by DNA damaging agents. In the present study, we have identified the antioxidant N-acetyl cysteine (NAC) as a powerful modifier of critical events downstream of the cell-permeable cAMP analog 8-(4-chlorophenylthio) adenosine-3′, 5′- cyclic monophosphate (8-CPT). Accordingly, we found NAC to turn 8-CPT into a potent killer of ALL cells in vitro both in the presence and absence of DNA damaging treatment. Furthermore, we revealed that NAC in combination with 8-CPT is able to delay the progression of ALL in a xenograft model in NOD-scid IL2Rγnull mice. NAC was shown to rely on the ability of 8-CPT to activate the guanine-nucleotide exchange factor EPAC, and we demonstrated that the ALL cells are killed by apoptosis involving sustained elevated levels of calcium imposed by the combination of the two drugs. Taken together, we propose that 8-CPT in the presence of NAC might be utilized as a novel strategy for treating pediatric ALL patients, and that this powerful combination might be exploited to enhance the therapeutic index of current ALL targeting therapies.
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Skah, Seham; Richartz, Nina; Duthil, Eva; Gilljam, Karin Margaretha; Bindesbøll, Christian & Naderi, Elin Hallan
[Vis alle 11 forfattere av denne artikkelen]
(2018).
cAMP-mediated autophagy inhibits DNA damage-induced death of leukemia cells independent of p53.
OncoTarget.
9(54),
s. 30434–30449.
doi:
10.18632/oncotarget.25758.
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Autophagy is important in regulating the balance between cell death and survival, with the tumor suppressor p53 as one of the key components in this interplay. We have previously utilized an in vitro model of the most common form of childhood cancer, B cell precursor acute lymphoblastic leukemia (BCP-ALL), to show that activation of the cAMP signaling pathway inhibits p53-mediated apoptosis in response to DNA damage in both cell lines and primary leukemic cells. The present study reveals that cAMP-mediated survival of BCP-ALL cells exposed to DNA damaging agents, involves a critical and p53-independent enhancement of autophagy. Although autophagy generally is regarded as a survival mechanism, DNA damage-induced apoptosis has been linked both to enhanced and reduced levels of autophagy. Here we show that exposure of BCP-ALL cells to irradiation or cytotoxic drugs triggers autophagy and cell death in a p53-dependent manner. Stimulation of the cAMP signaling pathway further augments autophagy and inhibits the DNA damage-induced cell death concomitant with reduced nuclear levels of p53. Knocking-down the levels of p53 reduced the irradiation-induced autophagy and cell death, but had no effect on the cAMP-mediated autophagy. Moreover, prevention of autophagy by bafilomycin A1 or by the ULK-inhibitor MRT68921, diminished the protecting effect of cAMP signaling on DNA damage-induced cell death. Having previously proposed a role of the cAMP signaling pathway in development and treatment of BCP-ALLs, we here suggest that inhibitors of autophagy may improve current DNA damage-based therapy of BCP-ALL - independent of p53.
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Soop, Graciela Lopez; Rønningen, Torunn; Rogala, Agnieszka; Richartz, Nina; Blomhoff, Heidi Kiil & Thiede, Bernd
[Vis alle 8 forfattere av denne artikkelen]
(2017).
AKAP95 interacts with nucleoporin TPR in mitosis and is important for the spindle assembly checkpoint.
Cell Cycle.
ISSN 1538-4101.
16(10),
s. 947–956.
doi:
10.1080/15384101.2017.1310350.
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Faithful chromosome segregation during mitosis relies on a proofreading mechanism that monitors proper kinetochore-microtubule attachments. The spindle assembly checkpoint (SAC) is based on the concerted action of numerous components that maintain a repressive signal inhibiting transition into anaphase until all chromosomes are attached. Here we show that A-Kinase Anchoring Protein 95 (AKAP95) is necessary for proper SAC function. AKAP95-depleted HeLa cells show micronuclei formed from lagging chromosomes at mitosis. Using a BioID proximity-based proteomic screen, we identify the nuclear pore complex protein TPR as a novel AKAP95 binding partner. We show interaction between AKAP95 and TPR in mitosis, and an AKAP95-dependent enrichment of TPR in the spindle microtubule area in metaphase, then later in the spindle midzone area. AKAP95-depleted cells display faster prometaphase to anaphase transition, escape from nocodazole-induced mitotic arrest and show a partial delocalization from kinetochores of the SAC component MAD1. Our results demonstrate an involvement of AKAP95 in proper SAC function likely through its interaction with TPR.
Se alle arbeider i NVA
Publisert
20. aug. 2015 10:05
- Sist endret
31. mars 2017 16:01
