低用量EPAおよびDHA投与によるDMBA誘発ラット乳癌におよぼす影響

金沢大学医学部附属病院これまでにEPAとDHAの乳癌発生に及ぼす影響について検討してきた。一方、EPAとDHAは脂肪酸代謝産物アラキドン酸の分解調律酵素シクロオキシゲナーゼ(以下COX)の阻害剤として知られている。さらに最近、乳癌、胃癌、大腸癌組織におけるCOXの発現が報告されている。そこで、我々は今回、乳癌細胞におけるCOX発現の意義、特に浸潤能との関連について細胞レベルで検討した。癌細胞が毛細血管やリンパ管内外へ浸潤するときには、基底膜や結合組織の構成蛋白質を局部的に分解する蛋白分解酵素(メタロプロテアーゼ(MMPs))の作用が必要である。癌細胞が分泌するこのようなMMPsは現在までに10数種類同定されており、このうちMMP-2、MMP-9はゼラチン、IV型コラーゲンを分解する酵素活性を持つものとして知られており、乳癌との関連が報告されている。しかしながら、MMPとCOXの関係を直接検討した報告はみられていない。ヒト乳癌細胞株Hs578Tを用いて、MMP-9の発現と、COXとの関連について検討した。本来Hs578TはCOX活性を示さないが、1μMのTPAを加えて24時間培養したところ、薄層クロマトグラフィーにてCOX活性の誘導が観察された。COXにはCOX-1とCOX-2の2つのアイソザイムが知られているが、Western blot analysisでは、COX-2が強発現していた。同時に行った、gelatin zymographyでは、TPAの添加前はMMP-2活性を認めるのみであったが、添加後にはMMP-2に加えMMP-9のバンドの出現が認められた。次に、TPA存在下にCOXの阻害剤であるインドメタシン(以下IM)を加え、同様の測定を行ったところ、MMP-9発現はIM濃度依存性に低下した。以上より、MMP-9発現にはCOX-2活性の有無が重要な役割を果たしているものと考えられた。We investigated influence of EPA and DHA to breast carcinogenesis. On the other hand, EPA and DHA are known as inhibitors of cyclooxygenase (COX) : enzyme, which regulated resolution of arachidonic acids. Recently, expressions of COX were reported in the tissue of breast cancer, gastric cancer, and colon cencer. Then, we studied significance of COX expression in breast cancer cell and relation to invasiveness of cancer cells in vitro. When cancer cells invade to capillary vessles or lymphatics, matrix metalloproteinases (MMPs) which resolve constructive protein of basement membrane and connective tissue are necessary. At present ten and few spices were isolated as MMPs product by ancer cells. MMP-2 and MMP-9 were known as showing enzyme activity resolve gelatin and type IV collagen, and the relation to breast cancer wes reported. However, there was no report that the relation between MMP and COX was evaluated, Therefore, we evaluated the relation between MMP-9 expression and COX using Hs578T,human breast cancer cell line. Hs578T cells showed induction of COX activity by addition of TPA to the culture medium. By Western blot analysis, COX-2 was overexpressed in the Hs578T cells. Gelatin zymography revealed expression of MMP-9 after addition of TPA.MMP-9 expression was reduced by indomethacin (IM) : inhibitor of COX.In conclusion, COX-2 activity plays an important role in expression of MMP-9.研究課題/領域番号:08671345, 研究期間(年度):1996 – 1997出典：研究課題「低用量EPAおよびDHA投与によるDMBA誘発ラット乳癌におよぼす影響」課題番号08671345（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-08671345/086713451997kenkyu_seika_hokoku_gaiyo/）を加工して作

EPAおよびDHAの乳癌発生、増殖、転移に及ぼす影響およびその機序について

金沢大学医学部・附属病院乳癌の発生率や死亡率は、欧米と日本では大きく異なっており、その原因の一つとして脂肪摂取の違いが上げられる。すなわち、前者ではn-6系の多価不飽和脂肪酸(主にリノール酸)、後者ではn-3系の多価不飽和脂肪酸(主にEPAあるいはDHA)を多く摂取することが知られている。実験的にもリノール酸は乳癌の発生、増殖、転移に促進的に働き、EPAあるいはDHAはそれらに抑制的に働くことが知られている。そのため、乳癌の多い欧米のみならず、増加しつつある日本でも、EPAあるいはDHAは乳癌の予防および治療の点から注目を浴びている。そこで、In vivoおよびIn vitroの研究でリノール酸、EPAおよびDHAの作用機序について研究し、次の結果を得た。(1)リノール酸は、マウスに移植したホルモン非依存性乳癌(MM48)の増殖および転移を促進し、EPAおよびDHAはそれらを抑制した。(2)リノール酸は、In vitroでヒト乳癌細胞(MDA-MB-231)のProstagland in EやLeukotriene Bの分泌、および細胞増殖を促進した。しかし、EPAおよびDHAはそれらを抑制し、EPAの抑制はn-3/n-6比が1:0.69、DHAのそれはn-3/n-6比が1:2.08以上で認められ、更にそれらの抑制は培地中のLeukotriene BよりもProstaglandin Eの濃度と相関することが明かとなった。(3)リノール酸は、In vitroでヒト乳癌細胞(MDA-MB-231およびMCF-7)の増殖を促進し、更にMCF-7乳癌細胞ではc-mycの発現を促進することが明かとなった。以上、リノール酸、EPAおよびDHAの乳癌に対する作用機序はアラキドン酸代謝産物やc-mycなど癌遺伝子が関与していることが示唆されたが、依然、不明な点が多い。しかし、EPAあるいはDHAは乳癌の予防および治療において重要な役割を果たすと思われる。Differences in the incidence and prognosis of breast cancer between Western women and Japanese or Eskimos (Greenland and Alaska) women may arise from contrasting patterns of dietary fat intake. Whereas the former group consumes high-fat diets containing n-6 polyunsaturated fatty acids (PUFAs), primary linoleic acid (LA), the latter group consumes large amounts of fat derived from fish oils containing n-3 PUFAs, mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). An inverse relationship has been found between the incidence of breast cancer and the level of fish consumption, suggesting a protective role of n-3 PUFAs from human breast cancer. Thus, n-3 PUFAs have a potential role as chemopreventive and treatment agents in breast cancer. Therefore, we have studied the promotive or inhibitory effects of linoleic acid, EPA and DHA on breast cancer in vivo and in vitro.(1) While linoleic acid promoted the growth and metastases of MM48 mammary tumor transplanted into mice, EPA and DHA inhibited them.(2) In an in vitro study, linoleic acid stimulated the secretion of prostaglandin E and leukotriene B and cell growth of MDA-MB-231 human breast cancer. In contrary, EPA and DHA inhibited them, particularly at the EPA/n-6 ratio of 1 : 0.69 and the DHA/n-6 ratio of 1 : 2.08. Moreover, the cell growth was correlated with the prostaglandin level rather than the leukotriene level.(3) In another in vitro study, linoleic acid stimulated the cell growth of MAD-MB-231 and MCF-7. Moreover, linoleic acid stimulated the c-myc expression in MCF-7.Therefore, it was suggested that the promotive or inhibitory effects of linoleic acid, EPA and DHA are mediated via the arachidonic products or oncogen such as c-myc. However, their exact mechanisms still remained unclear and further studies are needed.研究課題/領域番号:06671191, 研究期間(年度):1994 – 1995出典：研究課題「EPAおよびDHAの乳癌発生、増殖、転移に及ぼす影響およびその機序について」課題番号06671191（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-06671191/066711911995kenkyu_seika_hokoku_gaiyo/）を加工して作

Conservative Axillary Surgery May Prevent Arm Lymphedema without Increasing Axillary Recurrence in the Surgical Management of Breast Cancer

Axillary lymph node dissection (ALND) has been associated with postoperative morbidities, including arm lymphedema, shoulder dysfunction, and paresthesia. Sentinel lymph node (SLN) biopsy emerged as a method to assess axillary nodal status and possibly obviate the need for ALND in patients with clinically node-negative (cN0) breast cancer. The majority of breast cancer patients are eligible for SLN biopsy only, so ALND can be avoided. However, there are subsets of patients in whom ALND cannot be eliminated. ALND is still needed in patients with three or more positive SLNs or those with gross extranodal or matted nodal disease. Moreover, ALND has conventionally been performed to establish local control in clinically node-positive (cN+) patients with a heavy axillary tumor burden. The sole method to avoid ALND is through neoadjuvant chemotherapy (NAC). Recently, various forms of conservative axillary surgery have been developed in order to minimize arm lymphedema without increasing axillary recurrence. In the era of effective multimodality therapy, conventional ALND may not be necessary in either cN0 or cN+ patients. Further studies with a longer follow-up period are needed to determine the safety of conservative axillary surgery

DEVELOPMENT OF AUTOIMMUNE THROMBOCYTOPENIA AFTER HIGH-DOSE CHEMOTHERAPY AND AUTOLOGOUS PERIPHERAL BLOOD STEM CELL SUPPORT FOR METASTATIC BREAST CANCER

Autoimmune thrombocytopenia (AT) occurs after not only allogeneic but also autologous SCT following high-dose myeloablative chemotherapy against malignant tumors. A 50-year-old woman was diagnosed with metastatic breast cancer (MBC) and received myeloablative chemotherapy followed by autologous peripheral blood stem cell transplantation. Purpura developed on day +40 after transplantation, and a diagnosis of AT was made based on her bone marrow picture and elevation of serum PA-IgG level. Her thrombocytopenia was refractory to treatment with high-dose intravenous immune globulin (IVIG) and steroids. Although her platelet count recovered to within the normal range after splenectomy, 14 months after receiving SCT she died of disseminated intravascular coagulation syndrome caused by progression of cancer metastasis. There have been 10 reported cases of AT developing after high-dose myeloablative chemotherapy against malignant tumors followed by autologous SCT. We suggest that the thrombocytopenia after engraftment was caused by activation of dormant auto-immunity, which our patient potentially had, in conjunction with an insufficient quantity and quality of suppressor T-cells before complete reconstruction of the immune system after myeloablative conditioning. The clinical course of our patient was specific and different from previously reported cases since a splenectomy was necessary due to her thrombocytopenia being refractory to both steroid and IVIG therapy