Alternative TitleSignificance of NE-κB activation and therapeutic strategies for targeting its pathway in androgen-independent prostate cancer
Periodical title平成19(2007)年度 科学研究費補助金 基盤研究(C) 研究成果報告書概要 = 2007 Fiscal Year Final Research Report Summary
Note (General)金沢大学附属病院
ホルモン不応性前立腺癌の新たな治療法を開発していく上で,前立腺癌の再燃メカニズムを解明することは必要不可欠である.以前より,我々はホルモン不応性前立腺癌における分子標的として,転写制御因子NF-κBに着目し研究を進めてきた.近年NF-κBの活性化が癌細胞の増殖促進,アポトーシス抑制,血管新生誘導,転移能増強を誘導することが明らかになってきた.前立腺癌においては,恒常的なNF-κB活性の上昇がアンドロゲン非感受性前立腺癌細胞株で認められている一方,アンドロゲン感受性前立腺癌細胞株では認められていない.今回我々は,NF-κBの恒常的活性化という新たな視点から前立腺癌の再燃メカニズムを解明すると共に,NF-κB活性を効果的に抑制するための各種遺伝子阻害技術を検討し,ホルモン不応性前立腺癌に対する新たな治療戦略の確立を試みた.まず,恒常的なNF-κB活性の上昇が認められないアンドロゲン感受性前立腺癌細胞株LNCaPにおいて,アンドロゲンフリーの環境で培養すると,NF-κB活性の有意な上昇が認められた.この結果から,NF-κB活性の上昇はアンドロゲン依存性から非依存性への移行に何らかの形で関与しており,"アンドロゲン除去はヒト前立腺癌細胞株LNCaPにおけるNF-κB活性を亢進させる"ことを明らかにした.次に,NF-κBをターゲットとしたアンドロゲン非依存性前立腺癌に対する新規治療法を確立するために,NF-κBデコイ,ドミナントネガティブ,分子標的薬等の遺伝子阻害技術を用いてNF-κB転写活性を抑制し,抗腫瘍効果をin vitroで検討した.本研究期間内に,これら遺伝子阻害技術によるSCIDマウスを用いたin vivoの検討を行う予定であったが,LNCaPを用いた骨転移モデルの作製が困難であったため暗礁に乗り上げた状態にある.今後は,科研費の有無に関わらず,再燃前立腺癌の治療実験に有用な同モデルの作製に取り組む予定である.
Introduction: Although androgen ablation is the most effective therapy for androgen-dependent (AD) prostate cancer, it eventually fails with time and then a portion of the cancer relapses to androgen-independent (AI) prostate cancer. Recently it has become clear that constitutive activation of NF-κB is detrimental to a number of human malignancies including prostate cancer. Several reports have showed that NE-κB is constitutively activated in AI PC-3 and DU145 but not in AD LNCaP cell lines. LNCaP cell model is an excellent choice for the study of AI progression for the reason that derivative LNCaP AI sublines have been established. To elucidate the mechanisms responsible for an early step of AI progression, we determined the status of NE-κB activity in LNCaP cells after a brief androgen deprivation. Materials and Method: Transient transfections and luciferase assay were performed to compare NE-κB promoter activity in LNCaP cells with and without R1881, a synthetic analogue of androgen . Western blot analysis of NE-κB subunits and their inhibitor IκBα proteins, ELISA assay of NE-κB-dependent cytokines, and immunocytochemical localization of NF-κB subunit p65 in LNCaP cells were also performed. To verify that NE-κB activation can promote the growth of LNCaP cells, an adenoviral vector bearing superrepressor of IκBα (Ad-SR- IκBα), a dominant negative inhibitor of NF-κB, was assessed. Results: After R1881 deprivation, NE-κB promoter activity was markedly elevated (5 to 6-fold), and phosphorylated IκBα expression increased approximately 10-fold with time There was no significant change in the expression of p65, p50, or IκBα protein, and no evidence of altered IL-6, TNF-a, or IL-1β secretion up to 4 days after R1881 withdrawal. Immunostaining revealed that R1881 removal promoted the translocation of p65 from cytoplasm to cell nucleus, even though almost all p65 localized only to cytoplasm in the presence of R1881. Without R1881, blockade of NE-κB activity by Ad-SR- IκBα accelerated apoptosis and decreased cell growth as demonstrated by TUNEL and MTT assay, respectively. Conclusions: Our data suggest that NE-κB activation occurs rapidly after androgen deprivation in cultured human prostate cancer cells. NE-κB activation could arise as an early event for AI progression. We propose that increased IκBα phosphorylation and concomitant NE-KB activation account for the critical step of AI progression. Blocking NF-κB activation with Ad-SR- IκBα offers a novel therapeutic approach to induce the death of prostate cancer cells undergoing AI progression.
研究課題/領域番号:18591742, 研究期間(年度):2006 – 2007
出典：「ホルモン不応性前立腺癌におけるNFkB活性化の意義とその経路を標的とした治療戦略」研究成果報告書 課題番号18591742（KAKEN：科学研究費助成事業データベース（国立情報学研究所））（https://kaken.nii.ac.jp/ja/report/KAKENHI-PROJECT-18591742/185917422007kenkyu_seika_hokoku_gaiyo/)を加工して作成
Sourcehttps://kanazawa-u.repo.nii.ac.jp/?action=repository_action_common_download&item_id=55506&item_no=1&attribute_id=26&file_no=1
Related Materialhttps://kaken.nii.ac.jp/ja/search/?kw=40334768
https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-18591742/
https://kaken.nii.ac.jp/ja/report/KAKENHI-PROJECT-18591742/185917422007kenkyu_seika_hokoku_gaiyo/
Data Provider (Database)国立情報学研究所 : 学術機関リポジトリデータベース（IRDB）（機関リポジトリ）