Daley-Brown Danielle, Harbuzariu Adriana, Kurian Ann Anu, Oprea-Ilies Gabriela, Gonzalez-Perez Ruben Rene
Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA 30310, United States.
Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30322, United States.
World J Clin Oncol. 2019 Jun 24;10(6):222-233. doi: 10.5306/wjco.v10.i6.222.
Obesity is a recognized risk factor for endometrial cancer (EmCa) and other cancer types. Leptin levels are significantly increased in obese individuals. Leptin-induced signaling crosstalk [Notch, Interleukin-1 (IL-1) and leptin outcome, NILCO] has been associated with breast cancer progression. This complex signaling crosstalk affects cancer cell proliferation, migration, invasion, angiogenesis, apoptosis and chemoresistance. NILCO expression was previously detected in human EmCa. However, it is unknown whether leptin regulates NILCO and alters EmCa's response to chemotherapeutics. It is hypothesized that leptin induces NILCO and increases aggressiveness and chemoresistance in EmCa cells.
To determine whether leptin induces NILCO molecules in EmCa affecting cell proliferation, aggressiveness and chemoresistance.
Leptin's effects on the expression of NILCO molecules [mRNAs and proteins for Notch receptors (Notch1-4), ligands (JAG1 and DLL4) and downstream effectors (survivin, Hey2), and leptin (OB-R) and IL-1 (IL-1R tI) receptors] was examined in EmCa cells (type I: Ishikawa, and HEC-1A, and type II: An3Ca and KLE) using Real-time PCR and Western blot analysis, respectively. In addition, the effects of leptin on cell cycle, proliferation and cell invasion were determined using cytometric analysis (Cellometer Vision CBA system), MTT cell proliferation and Matrigel-based invasion assays, respectively. Inhibitors of leptin (nanoparticle-bound leptin peptide receptor antagonist-2, IONP-LPrA2), IL-1 (anti-IL-1R tI antibody) and Notch (siRNA interference RNA) were used to investigate NILCO's effects on cell proliferation and invasion. Leptin's effects on Paclitaxel cytotoxicity in EmCa cells was determined by the CCK8 and Cellometer-based Annexin V assays.
For the first time it was shown that leptin is an inducer of Notch in EmCa. Experimental data suggest that leptin induced the expression of NILCO molecules, promoted proliferation and S- phase progression, and reduced Paclitaxel cytotoxicity on EmCa cells. Leptin's effects were higher in type II EmCa cells. The progression of this more aggressive form of the disease is associated with obesity. Remarkably, the use of the leptin signaling antagonist, IONP-LPrA2, re-sensitized EmCa cells to Paclitaxel.
Present data suggest the notion that leptin-induced NILCO could be a link between obesity and EmCa progression and chemoresistance. Most aggressive type II EmCa cells were higher sensitive to leptin, which appears to increase proliferation, cell cycle progression, aggressiveness, and chemoresistance to Paclitaxel. Therefore, leptin and NILCO could be novel therapeutic targets for type II EmCa, which does not have targeted therapy. Overall, IONP-LPrA2 has a potential as a novel adjuvant drug to enhance the effectiveness of type II EmCa chemotherapy.
肥胖是子宫内膜癌（EmCa）及其他癌症类型公认的风险因素。肥胖个体的瘦素水平显著升高。瘦素诱导的信号串扰[Notch、白细胞介素-1（IL-1）和瘦素结果，NILCO]与乳腺癌进展相关。这种复杂的信号串扰影响癌细胞的增殖、迁移、侵袭、血管生成、凋亡和化疗耐药性。先前在人类EmCa中检测到NILCO表达。然而，瘦素是否调节NILCO并改变EmCa对化疗药物的反应尚不清楚。据推测，瘦素诱导NILCO并增加EmCa细胞的侵袭性和化疗耐药性。
确定瘦素是否诱导EmCa中的NILCO分子，影响细胞增殖、侵袭性和化疗耐药性。
分别使用实时PCR和蛋白质印迹分析，检测瘦素对EmCa细胞（I型：Ishikawa和HEC-1A，II型：An3Ca和KLE）中NILCO分子[Notch受体（Notch1-4）、配体（JAG1和DLL4）和下游效应分子（survivin、Hey2）的mRNA和蛋白质，以及瘦素（OB-R）和IL-1（IL-1R tI）受体]表达的影响。此外，分别使用细胞计数分析（Cellometer Vision CBA系统）、MTT细胞增殖和基于基质胶的侵袭试验，确定瘦素对细胞周期、增殖和细胞侵袭的影响。使用瘦素抑制剂（纳米颗粒结合的瘦素肽受体拮抗剂-2，IONP-LPrA2）、IL-1抑制剂（抗IL-1R tI抗体）和Notch抑制剂（小干扰RNA），研究NILCO对细胞增殖和侵袭的影响。通过CCK8和基于Cellometer的膜联蛋白V试验，确定瘦素对EmCa细胞中紫杉醇细胞毒性的影响。
首次表明瘦素是EmCa中Notch的诱导剂。实验数据表明，瘦素诱导NILCO分子表达，促进增殖和S期进展，并降低紫杉醇对EmCa细胞的细胞毒性。瘦素在II型EmCa细胞中的作用更强。这种侵袭性更强的疾病进展与肥胖有关。值得注意的是，使用瘦素信号拮抗剂IONP-LPrA2可使EmCa细胞对紫杉醇重新敏感。
现有数据表明，瘦素诱导的NILCO可能是肥胖与EmCa进展及化疗耐药性之间的联系。侵袭性最强的II型EmCa细胞对瘦素更敏感，瘦素似乎可增加增殖、细胞周期进展、侵袭性以及对紫杉醇的化疗耐药性。因此，瘦素和NILCO可能是II型EmCa的新型治疗靶点，目前II型EmCa尚无靶向治疗方法。总体而言，IONP-LPrA2有潜力作为新型辅助药物，提高II型EmCa化疗的有效性。
