Inhibition of USP1 reverses the chemotherapy resistance through destabilization of MAX in the relapsed/refractory B cell lymphoma

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The problem we encountered

Lymphoma is a type of malignant tumor originating from lymphocytes and is divided into Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL). Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of lymphoma, accounting for 30-35% of NHL(1, 2) . In recent years, 6-8 cycles of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) have become the standard treatment for DLBCL (3-7), and a good efficacy of the R-CHOP regimen has been achieved. However, some DLBCL patients with poor prognosis features remain resistant to therapy or relapse after short-term remission. It is therefore important to identify markers associated with the prognosis of DLBCL patients and the efficacy of the R-CHOP regimen, which will ultimately help in the exploration of new targeted therapies for rituximab/chemotherapy resistant DLBCL.

How we start

Previous studies have demonstrated that the ubiquitin-proteasome system plays an important role in the development of rituximab-chemotherapy resistance in B-cell lymphoma. Moreover, targeting the proteasome system with pharmacological inhibitors has resulted in significant anti-tumor activity in relapsed/refractory DLBCL (8, 9). USP1, a deubiquitinating enzyme, is a member of the ubiquitin-specific processing (USP) family of proteases (10) and implicated in cancer progression (11). As a deubiquitylation enzyme, USP1 binds to the target proteins and maintains their stability by removing the ubiquitylation chain. USP1 can deubiquitinate ID1 (inhibitor of DNA binding 1), a transcription regulator, which was identified to control leukemogenesis by us previously, and protected ID1 from proteasome-mediated degradation (12). Furthermore, it has been reported that USP1 can bind to ID proteins (13, 14), RPS16 (15), KDM4A/SIX1 (16, 17) and KPNA2 (18) in osteosarcoma, gastric cancer, hepatocellular carcinoma, prostate cancer and breast cancer respectively and maintain the stability of these proteins, which suggests that the target of USP1 could be cancer type-specific. To investigate whether the deubiquitination enzyme USP1 plays an important role in diffuse large B-cell lymphoma, we conducted our study.

What we find

To elucidate the potential role of USP1 in DLBCL, we detected the expression of USP1 by using immunohistochemical (IHC) analysis in 106 newly diagnosed DLBCL samples and 16 normal lymph node tissue samples. Our clinical analysis showed that Ubiquitin-specific protease 1 (USP1) was highly expressed in diffuse large B-cell lymphoma (DLBCL) patients, and its high expression predicted poor prognosis (Figure 1).

Figure 1. USP1 is highly expressed in DLBCL and associated with poor prognosis.

Until now, the function and underlying mechanism of USP1 in DLBCL has been unknown. Therefore, we hypothesized that USP1 could be a potential therapeutic target of the therapy for the relapsed/refractory DLBCL patients and investigated the role of USP1 in DLBCL. In this study, knocking down USP1 in DLBCL cells inhibited cell proliferation, induced cell cycle arrest, stimulated autophagy, and demonstrated therapeutic effects in a xenograft mouse model of the relapsed/refractory DLBCL. Interestingly, we find that USP1 interacts with MAX and maintains the stability of the MAX/MYC heterodimer, thereby regulating the transcription of MYC target genes. Pimozide, a specific inhibitor of USP1, could significantly suppress cell proliferation, block cell cycle, increase cell autophagy and retard the growth of lymphoma in the RL-4RH cells or patient-derived xenograft (PDX) mouse model. In addition, pimozide is synergetic with chemotherapeutics such as etoposide, both in vitro and in vivo.

Our conclusion

Our study suggests that Inhibition of USP1 reverses the chemotherapy resistance in the relapsed/refractory B Cell Lymphoma by destabilizing MAX and MYC. These findings suggest that USP1 has an important function in the relapsed/refractory DLBCL and may be a potential target for clinical therapy (Figure 2).

Figure 2. Schematic diagram of functions and molecular mechanisms of USP1 in DLBCL.

 

Reference

  1. Armitage JO, Weisenburger DD. New approach to classifying non-Hodgkin's lymphomas: clinical features of the major histologic subtypes. Non-Hodgkin's Lymphoma Classification Project. J Clin Oncol. 1998;16(8):2780-95.
  2. Jiang M, Bennani NN, Feldman AL. Lymphoma classification update: B-cell non-Hodgkin lymphomas. Expert Rev Hematol. 2017;10(5):405-15.
  3. Coiffier B, Lepage E, Briere J, Herbrecht R, Tilly H, Bouabdallah R, et al. CHOP chemotherapy plus rituximab compared with CHOP alone in elderly patients with diffuse large-B-cell lymphoma. N Engl J Med. 2002;346(4):235-42.
  4. Coiffier B, Thieblemont C, Van Den Neste E, Lepeu G, Plantier I, Castaigne S, et al. Long-term outcome of patients in the LNH-98.5 trial, the first randomized study comparing rituximab-CHOP to standard CHOP chemotherapy in DLBCL patients: a study by the Groupe d'Etudes des Lymphomes de l'Adulte. Blood. 2010;116(12):2040-5.
  5. Pfreundschuh M, Kuhnt E, Trumper L, Osterborg A, Trneny M, Shepherd L, et al. CHOP-like chemotherapy with or without rituximab in young patients with good-prognosis diffuse large-B-cell lymphoma: 6-year results of an open-label randomised study of the MabThera International Trial (MInT) Group. Lancet Oncol. 2011;12(11):1013-22.
  6. Pfreundschuh M, Schubert J, Ziepert M, Schmits R, Mohren M, Lengfelder E, et al. Six versus eight cycles of bi-weekly CHOP-14 with or without rituximab in elderly patients with aggressive CD20+ B-cell lymphomas: a randomised controlled trial (RICOVER-60). Lancet Oncol. 2008;9(2):105-16.
  7. Pfreundschuh M, Trumper L, Osterborg A, Pettengell R, Trneny M, Imrie K, et al. CHOP-like chemotherapy plus rituximab versus CHOP-like chemotherapy alone in young patients with good-prognosis diffuse large-B-cell lymphoma: a randomised controlled trial by the MabThera International Trial (MInT) Group. Lancet Oncol. 2006;7(5):379-91.
  8. Gu JJ, Hernandez-Ilizaliturri FJ, Kaufman GP, Czuczman NM, Mavis C, Skitzki JJ, et al. The novel proteasome inhibitor carfilzomib induces cell cycle arrest, apoptosis and potentiates the anti-tumour activity of chemotherapy in rituximab-resistant lymphoma. Br J Haematol. 2013;162(5):657-69.
  9. Gu JJ, Hernandez-Ilizaliturri FJ, Mavis C, Czuczman NM, Deeb G, Gibbs J, et al. MLN2238, a proteasome inhibitor, induces caspase-dependent cell death, cell cycle arrest, and potentiates the cytotoxic activity of chemotherapy agents in rituximab-chemotherapy-sensitive or rituximab-chemotherapy-resistant B-cell lymphoma preclinical models. Anticancer Drugs. 2013;24(10):1030-8.
  10. Fujiwara T, Saito A, Suzuki M, Shinomiya H, Suzuki T, Takahashi E, et al. Identification and chromosomal assignment of USP1, a novel gene encoding a human ubiquitin-specific protease. Genomics. 1998;54(1):155-8.
  11. Huang TT, Nijman SM, Mirchandani KD, Galardy PJ, Cohn MA, Haas W, et al. Regulation of monoubiquitinated PCNA by DUB autocleavage. Nat Cell Biol. 2006;8(4):339-47.
  12. Mistry H, Hsieh G, Buhrlage SJ, Huang M, Park E, Cuny GD, et al. Small-molecule inhibitors of USP1 target ID1 degradation in leukemic cells. Mol Cancer Ther. 2013;12(12):2651-62.
  13. Williams SA, Maecker HL, French DM, Liu J, Gregg A, Silverstein LB, et al. USP1 deubiquitinates ID proteins to preserve a mesenchymal stem cell program in osteosarcoma. Cell. 2011;146(6):918-30.
  14. Li N, Wu L, Zuo X, Luo H, Sheng Y, Yan J. USP1 Promotes GC Metastasis via Stabilizing ID2. Dis Markers. 2021;2021:3771990.
  15. Liao Y, Shao Z, Liu Y, Xia X, Deng Y, Yu C, et al. USP1-dependent RPS16 protein stability drives growth and metastasis of human hepatocellular carcinoma cells. J Exp Clin Cancer Res. 2021;40(1):201.
  16. Cui SZ, Lei ZY, Guan TP, Fan LL, Li YQ, Geng XY, et al. Targeting USP1-dependent KDM4A protein stability as a potential prostate cancer therapy. Cancer Sci. 2020;111(5):1567-81.
  17. Liao Y, Liu Y, Shao Z, Xia X, Deng Y, Cai J, et al. A new role of GRP75-USP1-SIX1 protein complex in driving prostate cancer progression and castration resistance. Oncogene. 2021;40(25):4291-306.
  18. Ma A, Tang M, Zhang L, Wang B, Yang Z, Liu Y, et al. USP1 inhibition destabilizes KPNA2 and suppresses breast cancer metastasis. Oncogene. 2019;38(13):2405-19.

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