Noma Bunjiro, Sasaki Tamito, Fujimoto Yoshifumi, Serikawa Masahiro, Kobayashi Kenso, Inoue Motoki, Itsuki Hiroshi, Kamigaki Michihiro, Minami Tomoyuki, Chayama Kazuaki
Department of Medicine and Molecular Science, Hiroshima University Graduate School of Biomedical Sciences, Minami-ku, Hiroshima 734-8551, Japan.
Int J Oncol. 2008 Dec;33(6):1187-94.
Despite the recent introduction of the new anticancer agents gemcitabine (GEM) and TS-1, as well as combination regimens such as GEM plus cisplatin (CDDP), pancreatic cancer treatment remains relatively ineffective. Both intrinsic and acquired resistance to chemotherapy are major roadblocks to the successful treatment of pancreatic cancer patients. The aims of this study were to examine the expression of multidrug resistance-associated proteins (MRPs) MRP1, MRP2 and MRP3 and to evaluate the correlation between MRP2 expression and CDDP resistance in human pancreatic cancer. Five human pancreatic cancer cell lines and several surgically resected pancreatic cancer tissues were subjected to reverse-transcriptase (RT)-PCR, real-time PCR and immunohistochemical analysis. While MRP1 and MRP2 mRNA was expressed in all cell lines, MRP3 mRNA was only detected in two cell lines. In resected pancreatic cancer tissues, only MRP2 mRNA was expressed and it was overexpressed compared with normal pancreatic tissues. MRP2 protein expression was observed in 77.5% (31/40) of cancer tissues, primarily in the cytoplasm of cancer cells, but was not observed in normal pancreatic tissue. Two CDDP-resistant pancreatic cancer cell line SUIT-2 variants, SUIT-2-CD3 and SUIT-2-CD4, were established by continuously administering 10 nM CDDP to SUIT-2 cell lines for 3 and 4 months, respectively. Incubation of these cells with CDDP in the presence of anti-MRP2 antibody or the MRP2 inhibitor MK-571 in a growth inhibition assay demonstrated that the CDDP-resistant variants were more resistant to CDDP than the parent cell line and this resistance was diminished by either anti-MRP2 antibody or MK-571. Moreover, RT-PCR and real-time PCR revealed that while induction of MRP2 mRNA expression was increased in CDDP-resistant compared with parent cells, MRP1 and MRP3 expression remained unchanged. These observations suggest that MRP2 may correlate to intrinsic and acquired resistance for CDDP in human pancreatic cancer.
尽管最近引入了新的抗癌药物吉西他滨（GEM）和替吉奥（TS-1），以及诸如GEM加顺铂（CDDP）的联合治疗方案，但胰腺癌的治疗仍然相对无效。化疗的内在和获得性耐药是成功治疗胰腺癌患者的主要障碍。本研究的目的是检测多药耐药相关蛋白（MRPs）MRP1、MRP2和MRP3的表达，并评估MRP2表达与人类胰腺癌中CDDP耐药性之间的相关性。对五种人类胰腺癌细胞系和一些手术切除的胰腺癌组织进行逆转录酶（RT）-PCR、实时PCR和免疫组织化学分析。虽然MRP1和MRP2 mRNA在所有细胞系中均有表达，但MRP3 mRNA仅在两个细胞系中检测到。在切除的胰腺癌组织中，仅表达MRP2 mRNA，与正常胰腺组织相比其表达上调。在77.5%（31/40）的癌组织中观察到MRP2蛋白表达，主要位于癌细胞的细胞质中，而在正常胰腺组织中未观察到。通过分别对SUIT-2细胞系连续给予10 nM CDDP 3个月和4个月，建立了两种对CDDP耐药的胰腺癌细胞系SUIT-2变体，即SUIT-2-CD3和SUIT-2-CD4。在生长抑制试验中，在抗MRP2抗体或MRP2抑制剂MK-571存在的情况下，用CDDP孵育这些细胞，结果表明对CDDP耐药的变体比亲本细胞系对CDDP更具耐药性，并且这种耐药性可被抗MRP2抗体或MK-571减弱。此外，RT-PCR和实时PCR显示，与亲本细胞相比，CDDP耐药细胞中MRP2 mRNA表达的诱导增加，而MRP1和MRP3表达保持不变。这些观察结果表明，MRP2可能与人类胰腺癌中CDDP的内在和获得性耐药相关。
