摘要:研究背景:雖然典型(canonical) NF-κB訊息傳遞路徑機轉已在侵襲性B細胞淋巴癌 (aggressive B-celllymphoma) 之致癌機制研究方面略為詳細,但對於非典型 (non-canonical) NF-κB訊息傳遞路徑在侵襲性B細胞淋巴癌之致癌機制所扮演角色仍未釐清和確定。通常non-canonical NF-κB訊息傳遞路徑活化過程,大多依賴CD40和B細胞活化因子接受體(BAFFR)之訊息所激發之p100磷酸化機制,和隨後所造成p52/RelB之異雙劇體釋放出來之過程。事實上,這訊息傳遞路徑過程也須TRAF3/TRAF2/c-IAP1/2之泛素連接酶多聚體型式複合物,NF-κB活化激酶 (NIK)和IKKα幫忙。最近研究也顯示BCL10 Ser138之磷酸化可上調節NIK之活化,而進一步導致non-canonical NF-κB訊息傳遞路徑活化。除此之外,我們也證實BAFF/BAFFR訊息傳遞路徑與胃瀰漫大型B細胞淋巴癌 (DLBCL) (Blood 2008;112:2927-34; Ann Hematol 2010;89:431-6) 和胃粘膜相關淋巴組織(MALT) 淋巴癌 (Genes Chromosomes Cancer 2011;50:908-21) 之幽門桿菌非依賴性生長有關,這現象顯示non-canonical NF-κB訊息傳遞路徑與B細胞淋巴癌致病機轉可能有相關性。初步研究成果:最近我們證實在淋巴結節外DLBCL 之淋巴癌檢體中, BAFF 之表現與核內NF-κB (p52)表現一致。且在DLBCL 細胞株上,持續活化BAFF/BAFFR 之訊息,可促進NIK 所引發之non-canonicalNF-κB 訊息傳遞路徑活化,且這機制與TRAF3 降低和BCL10 Ser138 之磷酸化有高相關性。同時,這些non-canonical NF-κB 訊息傳遞路徑活化現象也導致BCL3 核內轉移與STAT3 磷酸化作用。我們的初步研究成果與其他學者研究發現相呼應,更證明BCL3 與他所調控之STAT3,可能也參與NF-κB (p52)之訊息傳遞活化。我們也發現經由BAFF 所活化之non-canonical NF-κB 訊息傳遞路徑會減低everolimus (mTOR inhibitor) 在侵襲性B 細胞淋巴癌細胞株之療效。 我們更發現藉由小髮夾RNA(short hairpin RNA,shRNA)來抑制BAFF,可阻斷TRAF3/NIK/BCL3/NF-κB(p52) 訊息傳遞路徑,並進一步有效抑制DLBCL 和Burkitt lymphoma 等淋巴癌細胞株生長。研究假說:我們認為持續性活化non-canonical NF-κB 訊息傳遞路徑可能促進侵襲性B 細胞淋巴癌之生長和存活。為了證實假說,我們將分析一系列侵襲性B 細胞淋巴癌細胞株及侵襲性B 細胞淋巴癌腫瘤標本,其non-canonical NF-κB 訊息傳遞路徑相關基因之表現和這些基因所代表之生物意義,並特別針對下列侵襲性B 細胞淋巴癌: DLBCL (activated B cell [ABC]-like 及 germinal center Bcell [GCB]-like) ,CD5(+) DLBCL, 好發於老年之EBV(+) DLBCL, 和 Burkitt lymphoma,去作一完整性分析和研究。研究特殊目標:1. 藉由釐清non-canonical NF-κB 訊息傳遞路徑之基因 (BAFF、 BAFFR、CD40、 TRAF3、NIK、 NF-B2、 BCL10、BCL3、 和STAT3),和這些基因所代表之生物意義及生物機轉,在侵襲性B 細胞淋巴癌的致癌機制中所扮演角色之研究。2. 探討不同類型之侵襲性B 細胞淋巴癌間,例如: (1) ABC-DLBCL versus GCB-DLBCL (2)CD5(+) DLBCL-預後較好 versus CD5+ DLBCL-預後較不好 (2) 好發於老年之EBV(+)DLBCL versus Burkitt lymphoma 之間,其non-canonical NF-κB 訊息傳遞路徑之相關基因表現差別。3. 進一步探討和評估BAFF 抑制劑, CD40 抑制劑,STAT3 抑制劑和NF-κB 抑制劑及修飾non-canonical NF-κB 訊息傳遞路徑之相關基因 (TRAF3, NIK, BCL10, and BCL3)來治療侵襲性B 細胞淋巴癌。預期研究結果:1. 可充分釐清及了解non-canonical NF-κB 訊息傳遞路徑在侵襲性B 細胞淋巴癌之致癌機制的潛在分子機轉。2. 發展具有相當潛力且極重要之標靶藥物來做為未來治療侵襲性B 細胞淋巴癌病人之治療策略。
Abstract: Background: Although the canonical NF-κB signaling pathway has been studied in some detail, thenon-canonical NF-κB signaling pathway in lymphomagenesis of aggressive B-cell lymphoma is notwell characterized. Non-canonical NF-κB pathway relies on phosphorylation-induced p100 processingand subsequent liberation of the p52/RelB active heterodimer, which is triggered by signaling fromCD40 and B cell-activating factor receptor (BAFFR). This pathway is dependent onTRAF3/TRAF2/c-IAP1/2 ubiquitin ligase multimeric complex, NF-κB–inducing kinase (NIK), andIKKα. Recent studies suggest that BCL10 Ser138 phosphorylation act upstream of phosphorylations ofNIK and further activate non-canonical NF-κB signaling. Our recent works have demonstrated thatautocrine BAFF/BAFFR signal transduction pathways may contribute to H. pylori-independentgrowth of gastric diffuse large B-cell lymphoma (DLBCL) with mucosa-associated lymphoid tissue(MALT) (Blood 2008;112:2927-34; Ann Hematol 2010;89:431-6) and MALT lymphoma (GenesChromosomes Cancer 2011;50:908-21), indicating that non-canonical NF-κB pathway may involve inthe pathogenesis of B-cell lymphomas.Preliminary results: Recently, we demonstrated that overexpression of BAFF is closely associatedwith nuclear expression of NF-B (p52) in extranodal DLBCL. Further, we found that in DLBCLlymphoma cell lines, constitutive BAFF/BAFFR signaling activates NIK-induced non-canonicalNF-B pathway activation through induction of TRAF3 degradation, and BCL10 Ser138phosphorylation. This effect also resulted in BCL3 nuclear translocation and STAT3 phosphorylation,supporting the other investigator’s observation that BCL3 and its regulated STAT3 gene may affecttheir regulation of non-canonical p52 activity. Our preliminary results showed that up-regulation ofnon-canonical NF-B signaling pathway by BAFF lessened the inhibition of cell viability ofeverolimus (mTOR inhibitor) in aggressive B-cell lymphoma. Furthermore, we found that inhibitionof BAFF by short hairpin RNA (shRNA) suppressed the growth of DLBCL and Burkitt lymphomacells through the down-regulation of TRAF3/NIK/BCL3/NF-B (p52) signaling pathway.Hypotheses: Constitutive activation of non-canonical NF-B signaling pathway may promote thesurvival and proliferation of aggressive B-cell lymphoma. To prove this, we will analyzenon-canonical NF-B signatures-related genes and their biologic significances in a series ofaggressive B-cell lymphoma cell lines and tumor specimens, focusing on DLBCL (activated B cell[ABC]-like, and germinal center B cell [GCB]-like), CD5(+) DLBCL, EBV(+) DLBCL of elderly,and Burkitt lymphoma.Specific aims:[1]. Clarification of non-canonical NF-B signatures-related genes (BAFF, BAFFR, CD40, TRAF3,NIK, NF-B2, BCL10, BCL3, and STAT3), and their biologic significances and molecularmechanisms in the lymphomagenesis of aggressive B-cell lymphoma.[2]. Exploration of the difference in the gene expression pattern of non-canonical NF-B signaturesand clinicopathologic features between (1) ABC-DLBCL versus GCB-DLBCL (2) CD5(+)DLBCL-better prognosis versus CD5(+) DLBCL-poor prognosis (2) EBV(+) DLBCL of elderlyversus Burkitt lymphoma.[3]. Further evaluation of the efficacy of BAFF inhibitor, CD40 inhibitor, STAT3 inhibitor, andNF-B inhibitors, and the modulation of non-canonical NF-B-signaling related genes (TRAF3,NIK, BCL10, and BCL3) in the treatment of aggressive B-cell lymphoma.Major anticipated achievements: (1) A better understanding of underlying molecular mechanisms ofnon-canonical NF-B-signaling in the lymphomagenesis of aggressive B-cell lymphoma (2)Development of potentially important targets for future therapeutic strategies in patients withaggressive B-cell lymphoma.