Targeting the long isoform of the prolactin receptor to treat autoimmune diseases and B-cell malignancies

项目总结 早期干预高危B细胞恶性肿瘤，包括弥漫性大B细胞淋巴瘤(DLBCL)，Burkitt‘s 淋巴瘤(BL)和B细胞急性淋巴细胞白血病(B-ALL)仍然是临床上迫切需要的疾病。发展 这种干预措施需要对进化背后的分子机制有深刻的理解，即， 这些恶性肿瘤的起源、形成和维持。B细胞恶性肿瘤的发病率是前者的5倍以上 常见于患有难治性自身免疫性B淋巴增生性疾病的患者，如系统性 红斑狼疮(SLE)，使SLE成为研究B细胞肿瘤发生的相关疾病模型。这个 已知激素催乳素(PRL)可加重系统性红斑狼疮的症状，提高淋巴细胞的存活率，以及 促进原癌基因MYC和BCL2在这些细胞中的表达。PRL是否有助于 B细胞恶性肿瘤的演变尚不清楚。催乳素受体(PRLRs)是I型细胞因子受体 具有通过选择性剪接产生的长(LF)、中间(如果，仅在人类)和短(SF)异构体。 细胞上LF/IF相对SF PRLRs的表达增加导致细胞增殖和存活， 而相对于LF/IF，SFS的表达增加则抑制增殖，促进分化，并诱导 细胞凋亡。我们假设PRL，通过特异性地通过促增殖和抗凋亡信号传递 Lf/IFPRLR，促进B细胞的恶性转化，建立和维持外显性T细胞的生长 B细胞恶性肿瘤。为了验证我们的假设，我们测量了SLE-和DLBCL/BL-体内B细胞的变化。 易感小鼠模型及体外人B细胞恶性肿瘤后特异性敲除后的表达 LF/IFPRLR使用无毒的剪接调节低聚物(SMO)。LFPRLR SMO阻止合成 在不影响SFPRLR的情况下，对小鼠的LFPRLR和人类的LF/IFPRLR产生影响。击倒 LFPRLR降低SLE和DLBCL/BL易感小鼠致病B细胞亚群的数量 下调活化诱导型胞苷的表达对SLE易感小鼠B细胞转化的风险 我们之前展示的脱氨酶(AID)酶的过度表达推动了B细胞的进化 肿瘤。我们发现，显性人类B细胞肿瘤异常地表达自分泌PRL，有时仅 LF/IFPRLR。在显性B细胞恶性肿瘤中敲除LF/IFPRLR降低了细胞存活率，下调了STAT3 MYC和bcl2的激活和表达。我们的初步发现保证了对分子的详细研究 系统性红斑狼疮易感小鼠LF/IFPRLR下游B细胞紊乱的潜在途径 易转化(目标1)，具有易患明显B细胞恶性肿瘤的癌前B细胞克隆的小鼠 (目标2)，以及在临床人类B细胞肿瘤中(目标3)。我们的研究将巩固异构体特异性抑制 产生LF/IFPRLR作为SLE的一种治疗策略，同时降低B- 这些患者中的细胞恶性肿瘤(目标1)，在有癌前和惰性B细胞的人中，这些人是脆弱的 发展为侵袭性B细胞恶性肿瘤(目标2)，以及临床B细胞肿瘤(目标3)。

PROJECT SUMMARY Early interventions for high-risk B-cell malignancies, including diffuse large B cell lymphoma (DLBCL), Burkitt's Lymphoma (BL), and B-cell acute lymphoblastic leukemia (B-ALL), remain an urgent clinical need. Development of such interventions requires a deep understanding of the molecular mechanisms underlying the evolution, i.e., initiation, establishment, and sustenance, of these malignancies. B-cell malignancies are initiated >5-fold more frequently in patients suffering from refractory autoimmune B-lymphoproliferative disorders such as systemic lupus erythematosus (SLE), making SLE a relevant disease model to study initiation of B-cell neoplasms. The hormone prolactin (PRL) is known to exacerbate the symptoms of SLE, enhance survival of lymphoid cells, and promote the expression of the protooncogenes MYC and BCL2 in these cells. Whether PRL contributes to evolution of B-cell malignancies was unknown. PRL receptors (PRLRs) are type I cytokine receptors that have long (LF), intermediate (IF, only in humans) and short (SF) isoforms generated by alternative splicing. Increased expression of the LF/IF relative to the SF PRLRs on cells leads to cell proliferation and survival, whereas increased expression of SFs relative to LF/IF inhibits proliferation, promotes differentiation, and induces apoptosis. We hypothesized that PRL, by signaling specifically through the pro-proliferative and anti-apoptotic LF/IFPRLR, promotes the malignant transformation of B cells, and establishes and sustains the growth of overt B-cell malignancies. To test our hypothesis, we measured changes in B cells in vivo in SLE- and DLBCL/BL- prone mouse models and in vitro in human B-cell malignancies after specifically knocking down expression of the LF/IFPRLR using a non-toxic splice modulating oligomer (SMO). The LFPRLR SMO prevents the synthesis of the LFPRLR in mice and the LF/IFPRLR in humans without affecting the SFPRLRs. Knockdown of LFPRLR reduced the numbers of pathogenic B-cell subsets in SLE- and DLBCL/BL-prone mice and lowered the risk of B-cell transformation in SLE-prone mice by downregulating expression of the activation-induced cytidine deaminase (AID) enzyme, whose overexpression we previously showed, drives the evolution of B-cell neoplasms. We found that overt human B-cell neoplasms aberrantly express autocrine PRL and sometimes only the LF/IFPRLR. Knockdown of LF/IFPRLR in overt B-cell malignancies reduced cell viability, downstream STAT3 activation, and expression of MYC and BCL2. Our preliminary findings warrant detailed studies of molecular pathways underlying the disturbances in B cells downstream of LF/IFPRLR in SLE-prone mice that are vulnerable to transformation (Aim 1), in mice with pre-malignant B-cell clones prone to overt B-cell malignancies (Aim 2), and in overt human B-cell neoplasms (Aim 3). Our research will solidify isoform-specific suppression of the production of LF/IFPRLR as a therapeutic strategy in SLE that concurrently lowers the incidence of B- cell malignancies in these patients (Aim 1), in people with pre-malignant and indolent B cells who are vulnerable to developing aggressive B-cell malignancies (Aim 2), and in overt B-cell neoplasms (Aim 3).