NIHの助成金のP30のCA051008とT32 CA009686（ATR）でサポートされています。

スフェロイドの1世代<ol><li> PBSを用いて70％のコンフルエンス〜の接着性癌細胞培養物を分離することによって、ドロップ培養を掛けるために、単一細胞懸濁液を調製し、0.05％トリプシン-EDTA溶液への暴露に続いて洗浄します。 <ol><li>細胞培養培地でトリプシン溶液を中和し、細胞懸濁液のアリコートを用いて細胞を数えます。注記：特定の細胞培養培地は、試験される細胞株に依存します。細胞培養培地は、典型的には、DMEM + 10％FBSであり、ATCCメディアの推奨事項に従ってください。詳細については、資料の表に記載されています。 </li><li>細胞培養培地20μlのドロップあたり500〜1,000細胞の播種を可能にするために希釈を実行します。 </li></ol></li><li> 10cmディッシュを取得し、底に滅菌5mlのPBSを追加。注：このステップでは、吊り蒸発から落下保護します。細胞が続きないので「細菌グレード」皿を、細胞培養等級皿の代わりに使用することができる低コスト培養面として作用します。 </li><li>蓋の内面に希釈した細胞懸濁液の20μlの液滴を転送するためにマルチチャンネルピペットを使用します。 <ol><li>ピペット40は、10cmの皿の蓋の上に（8滴の5行）をドロップします。 </li></ol></li><li>培養皿の上に蓋と場所を反転。スフェロイドを生成するために、72時間、37℃で懸滴培養物をインキュベートします。 <ol><li>自信を持って、まだ制御された方法で蓋を反転します。注意：蓋が速すぎたり遅すぎ反転させると、液滴がシフトする可能性があります。他のものはコンパクト凝集体を生成するために72時間以上を必要とするかもしれないいくつかの細胞株は、48時間以下でスフェロイドを形成することができます。 </li></ol></li></ol> 3Dマトリックスへのスフェロイドの2埋め込み<ol><li>一晩スフェロイドを埋め込む前に、4°Cで成長因子低減基底膜材料のアリコートを解凍します。 <ol><li>オプション：組織cultuの潜在的な回転楕円体との相互作用を防止するために、事前にECMとのレイヤウェル表面再。 <ol><li> 24ウェルプレートにウェル当たりECMのピペットで200μlの。 </li><li> ECMは全体ウェル表面を覆っていることを確認するために、プレートを傾けます。 </li><li>慎重にピペットで余分なECMを削除します。 </li><li> 3時間、室温または4℃で一晩：井戸が乾燥するまで、プレートをインキュベートします。 </li></ol></li></ol></li><li>組織培養皿の蓋を傾け、メディアをプールすることによりスフェロイドを収集します。 1.5mlの微小管にスフェロイドとメディアを転送します。 </li><li>スフェロイドのための10分は、マイクロチューブの底に沈降することを許可します。スフェロイドを目で見えるようにする必要があります。 </li><li>私は独立した予備冷却管に型コラーゲン冷たい100μlの（4℃）と基底膜材料の100μLを混合します。途中で固化からゲルのいずれかを防ぐために4℃で混合物を保管してください 。 <ol><li>小さなボリュームを転送する場合はあらかじめ冷却ピペットチップを使用してください。 </li><li>するときには注意を与えますIは、気泡の形成を防止するために、基底膜の材料や型コラーゲンを混合します。注：彼らはゲル中に埋め込 ​​まれたとなった場合に気泡が 、後のプロトコルでの撮像を妨げることがあります。 </li></ol></li><li>マイクロチューブの40μlの底部分からのスフェロイドを吸引し、そして私は、混合物をコラーゲン基底膜材料/タイプと組み合わせます。混合する際に気泡形成を防止するように注意してください。注：100μlの基底膜の素材を含む溶液、100μlのコラーゲンI型、およびスフェロイド40μlのは、4つの独立した3次元培養のための十分な材料を作成します。これは、拡大または縮小することができます。 </li><li>ピペットで24ウェルプレート上のウェルの中心に粘性混合物の40μlの滴。ウェルの側に実行してから、混合物を防ぐために、プレートのレベルを保持します。注：24ウェルプレート上の単一の列 - 4ウェルが - 各条件がテストされることをお勧めします。 </li><li>プレートINTを置きますOA 37℃のインキュベーターで30分間乱されていないままにしておきます。 3D培養はこの期間中に重合します。 </li><li>ゆっくりと細胞培養培地1ml中に三次元培養を沈めます。 <ol><li>さらにゲル重合を促進するためにウェルにそれを追加するときにメディアが暖かいであることを確認してください。 </li><li>重要なステップ： 静か 3D培養にメディアを追加 。ウェルに早すぎるメディアをピペットは、組織培養表面から3D培養の離脱につながることができます。 </li></ol></li></ol> 3.スフェロイドの侵入を監視し、分析<ol><li>研究者が決定した時点での周囲の3次元マトリックスにスフェロイドからの画像侵攻。 20倍対物レンズを倒立顕微鏡を用いて写真を取得します。注：理想の時点は、試験される細胞株によって異なります。より侵襲的な細胞株はすぐにメッキ後のスフェロイドからの出力を開始し、そのため、最初の写真がかかりますメッキ後の数時間内の。一般的に、写真は（メッキ後）0時間、24時間、および48時間で採取されます。侵攻は通常、播種後24〜48時間を終了します。 </li><li>画像J.のような画像解析ソフトを使用して侵襲的な能力を定量<ol><li>回転楕円体の端からセル距離として侵略を分析します。 <ol><li>半径および/または最大侵襲距離をマークするためにストレートドローツールを使用します。 </li><li>トップメニューの「分析」をクリックして、[長さ測定値を表示するには、「測定」をクリックします。 </li></ol></li><li>回転楕円体の外側全体の侵襲領域として侵略を分析します。 <ol><li>回転楕円体および/または総侵襲的領域の境界をトレースするフリーハンド描画ツールを使用します。 </li><li>トップメニューの「分析」をクリックして、[面積計測を表示するには、「測定」をクリックします。 </li></ol></li><li>画像のスタックのための測定を作成するために、ROIマネージャーツールなどのプラグインを使用してください。 </li></ol>
	</li>
</ol>

<ol>
	<li>Chambers, A. F., Groom, A. C., MacDonald, I. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metastasis:+Dissemination+and+growth+of+cancer+cells+in+metastatic+sites.">Metastasis: Dissemination and growth of cancer cells in metastatic sites.</a> Nat Rev. Cancer. 2 (8), (2002).</li><li>Schmeichel, K. L., Bissell, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+tissue-specific+signaling+and+organ+function+in+three+dimensions.">Modeling tissue-specific signaling and organ function in three dimensions.</a> J Cell Sci. 116 (12), 2377-2388 (2003).</li><li>Yamada, K. M., Cukierman, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+tissue+morphogenesis+and+cancer+in+3D.">Modeling tissue morphogenesis and cancer in 3D.</a> Cell. 130 (4), (2007).</li><li>Foty, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+hanging+drop+cell+culture+protocol+for+generation+of+3D+spheroids.">A simple hanging drop cell culture protocol for generation of 3D spheroids.</a> J Vis Exp. 51, (2011).</li><li>Del Duca, ., Werbowetski, D., T, ., Del Maestro, R., F, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spheroid+preparation+from+hanging+drops:+characterization+of+a+model+of+brain+tumor+invasion.">Spheroid preparation from hanging drops: characterization of a model of brain tumor invasion.</a> J Neuro-Oncol. 67 (3), (2004).</li><li>Justus, C. R., Leffler, N., Ruiz-Echevarria, M., Yang, L. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+cell+migration+and+invasion+assays.">In vitro cell migration and invasion assays.</a> J Vis Exp. 88, (2014).</li><li>Ramos-DeSimone, N., Hahn-Dantona, E., Sipley, J., Nagase, H., French, D. L., Quigley, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Activation+of+matrix+metalloproteinase-9+(MMP-9)+via+a+converging+plasmin/stromelysin-1+cascade+enhances+tumor+cell+invasion.">Activation of matrix metalloproteinase-9 (MMP-9) via a converging plasmin/stromelysin-1 cascade enhances tumor cell invasion.</a> J Bio Chem. 274 (19), .</li><li>Friedl, P., Wolf, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumour-cell+invasion+and+migration:+diversity+and+escape+mechanisms.">Tumour-cell invasion and migration: diversity and escape mechanisms.</a> Nature Rev. Cancer. 3 (5), 362-374 (2003).</li><li>Kleinman, H. K., Martin, G. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Matrigel:+Basement+membrane+matrix+with+biological+activity.">Matrigel: Basement membrane matrix with biological activity.</a> Semin Cancer Biol. 15 (5), 378-386 (2005).</li><li>Shaw, L. M., Chao, C., Wewer, U. M., Mercurio, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Function+of+the+integrin+&#945;6&#946;1+in+metastatic+breast+carcinoma+cells+assessed+by+expression+of+a+dominant-negative+receptor.">Function of the integrin &#945;6&#946;1 in metastatic breast carcinoma cells assessed by expression of a dominant-negative receptor.</a> Cancer Res. 56 (5), 959-963 (1996).</li><li>Hughes, C. S., Postovit, L. M., Lajoie, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Matrigel:+a+complex+protein+mixture+required+for+optimal+growth+of+cell+culture.">Matrigel: a complex protein mixture required for optimal growth of cell culture.</a> Proteomics. 10 (9), (2010).</li><li>Rajan, N., Habermehl, J., Cot&#233;, M. -. F., Doillon, C. J., Mantovani, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+of+ready-to-use,+storable+and+reconstituted+type+I+collagen+from+rat+tail+tendon+for+tissue+engineering+applications.">Preparation of ready-to-use, storable and reconstituted type I collagen from rat tail tendon for tissue engineering applications.</a> Nat Protoc. 1 (6), (2006).</li><li>Provenzano, P. P., Eliceiri, K. W., Campbell, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Collagen+reorganization+at+the+tumor-stromal+interface+facilitates+local+invasion.">Collagen reorganization at the tumor-stromal interface facilitates local invasion.</a> BMC Med. 4 (1), (2006).</li><li>Timmins, N. E., Nielsen, L. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+multicellular+tumor+spheroids+by+the+hanging-drop+method.">Generation of multicellular tumor spheroids by the hanging-drop method.</a> Methods Mol Med. 140, 141-151 (2007).</li><li>Brenner, W., Gro&#223;, S., Steinbach, F., Horn, S., Hohenfellner, R., Th&#252;roff, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+inhibition+of+renal+cancer+cell+invasion+mediated+by+fibronectin,+collagen+IV+and+laminin.">Differential inhibition of renal cancer cell invasion mediated by fibronectin, collagen IV and laminin.</a> Cancer Lett. 155, 199-205 (2000).</li><li>Nieman, M. T., Prudoff, R. S., Johnson, K. R., Wheelock, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N-cadherin+promotes+motility+in+human+breast+cancer+cells+regardless+of+their+E-cadherin+expression.">N-cadherin promotes motility in human breast cancer cells regardless of their E-cadherin expression.</a> J Cell Biol. 147 (3), .</li><li>Cheung, K. J., Gabrielson, E., Werb, Z., Ewald, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Collective+invasion+in+breast+cancer+requires+a+conserved+basal+epithelial+program.">Collective invasion in breast cancer requires a conserved basal epithelial program.</a> Cell. 155 (7), (2013).</li><li>Sodek, K. L., Brown, T. J., Ringuette, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Collagen+I+but+not+Matrigel+matrices+provide+an+MMP-dependent+barrier+to+ovarian+cancer+cell+penetration.">Collagen I but not Matrigel matrices provide an MMP-dependent barrier to ovarian cancer cell penetration.</a> BMC Cancer. 8 (1), 223-2210 (2008).</li><li>Nguyen-Ngoc, K. V., Ewald, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mammary+ductal+elongation+and+myoepithelial+migration+are+regulated+by+the+composition+of+the+extracellular+matrix.">Mammary ductal elongation and myoepithelial migration are regulated by the composition of the extracellular matrix.</a> J Microsc. 251 (3), 212-223 (2013).</li><li>Glinskii, A. B., Smith, B. A., Jiang, P., Li, X., Yang, M., Hoffman, R. M., Glinsky, G. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Viable+circulating+metastatic+cells+produced+in+orthotopic+but+not+ectopic+prostate+cancer+models.">Viable circulating metastatic cells produced in orthotopic but not ectopic prostate cancer models.</a> Cancer Res. 63 (14), 4239-4243 (2003).</li></ol>

The authors declare that they have no competing financial interests.

この研究では、スフェロイド浸潤アッセイ（ 表1）の癌細胞株のパネルの性能を評価しました。一般的に、我々はスフェロイド形成が細胞間結合の存在は、回転楕円体のような構造の形成を促進する複数の上皮に見える細胞株に増強されることを見つけます。 MDA-MB-231細胞のような上皮間葉移行を経験した既知の細胞系は、それらの減少E-、N-およびP-カドヘリン発現16に最...

これは、癌細胞の運動性がこのような行為は、基底膜および循環系1への参入を通じて侵入を促進することを考えると、転移の可能性を予測することが確立されています。運動に関するほとんどの研究は、それが広く、三次元（3D）マトリクスの細胞の動きがする実際にどのようにこれらの同じ細胞のより代表的であることが認識されてきているものの、細胞が、二次元（2D）の設定でどのように動作するかに焦点を当てています生体 2 で動作します。 3D培養システムは、ますます増殖動態および薬物感受性3に、細胞形態の範囲での細胞挙動を研究するために使用されます。 3D環境のコンテキスト内での癌細胞の浸潤をモニターするための欲求は、3Dの外に、これらのスフェロイドを埋め込 ​​む続いハンギングドロップ培養法4を介して3D細胞凝集体（スフェロイド）の生成を含む、以前に確立された技術の合成につながっています行列（ECM）コラーゲンと基底膜材料5で構成される。この方法は、簡単な実験、種々の条件下で浸潤を比較するために利用することができる効率的なアプローチを提供することにより、これらの以前に確立された技術を改良することを目的とします。 in vitroで細胞の運動性を評価するためのより多くの伝統的な方法は、スクラッチ巻きアッセイおよびトランスウェルアッセイ6です。前者の分析は、2D設定で細胞の運動性を示し、したがって、in vivoでの侵略、 例えばプロテアーゼ活性 7のための重要な機能の様々な独立しています。トランスウェルアッセイは、より良いウェルインサートは、ECM基質でコーティングされたが、単一のパラメータのみ、反対側の膜表面上の細胞の出現、すなわちされたモデル細胞の浸潤を測定したり、細胞浸潤の多くのニュアンスは、このように容易に観察されません。これらの技術とは対照的に、癌細胞スフェロイド浸潤アッセイ（ 図1 &lt;/ strong&gt;の）だけで、生理学的に関連しない設定に細胞浸潤のリアルタイム監視が可能になり、だけでなく、個々の対集団細胞遊走8として可視化されるべき重要な細胞株固有の機能を、許可します。この方法はまた、標準的な三次元培養増殖アッセイを超える利点を提供します。細胞は、この制約が解除された後に侵入する奨励されるように、ハンギングドロップ法を介した細胞凝集体の生成は、最初に、細胞運動を抑制します。その制約が解除された後さらに、細胞放出はその後便利に定量することができる一定の方向に進むことになります。 癌細胞スフェロイドのアッセイのために使用される最も人気のあるECM材料は、マトリゲルとこれらの各コンポーネントは、転移挙動に影響を与える上で重要と異なる役割を持っているI型コラーゲン、あります。マトリゲルは、エンゲルホルム、スウォームマウス肉腫細胞によって産生されるタンパク質の分泌混合物であり、かつbasemeに富みますラミニン、エンタクチン、およびIV型コラーゲンなどの9ヌクレオチド膜タンパク質。この理由のために、マトリゲルを今後とも呼ばれる「基底膜材料。」これらの基底膜材料を細胞の挙動11への影響の範囲を発揮する多くの他のタンパク質に加えて、癌細胞の浸潤10中インテグリン接着のために必要不可欠なリガンドを提供します。比較では、一般的に腱および他の高密度のコラーゲン構造物12の酸消化物から調製されたI型コラーゲンは、身体の組織および器官を支持する結合組織と間質の主要な構造要素として機能する非常に単純なマトリックス材料です。それは、コラーゲンの物理的特性は、細胞運動性の機能の数を調節することができることが実証されています。例えば、腫瘍間質界面におけるコラーゲン線維の整列は、基質13内に侵入したときに、その後、それらの線維に沿って移動するように癌細胞を許可します。ここで紹介するアッセイでは、両方のI型コラーゲンと基底膜の材料は、3Dがん細胞間質の相互作用を研究するためのツールと​​して利用されています。 細胞は三次元マトリックス中に埋め込まれた後の侵入を制御する経路の阻害または刺激の効果をモニターすることができます。細胞は、長い治療が侵入を調節するために必要とされるかどうかに応じて、ハンギングドロップまたは3D培養に移す際に、成長中に前処理することができます。短い治療のためには、薬物が収集後のスフェロイド懸濁物、ならびに細胞への適切な薬物暴露を容易にするために、3次元培養を取り囲む培地と混合することをお勧めします。次に、正常または腫瘍関連間質細胞は、腫瘍細胞浸潤の調節におけるそれらの役割を評価するために、またはどのように傍分泌および自己分泌シグナル伝達に影響を与える細胞の挙動を決定するために、マトリックス材料と混合することができます。このアイデアは、COLの共培養の研究で示されました懸滴中の癌細胞および内皮細胞上でスフェロイド14内の血管網につながりました。癌細胞の浸潤は、異なる基板15の影響を受けるように、最終的に、ECMの成分はまた、変更することができます。以下に示す方法は、このように様々な条件下での癌細胞の浸潤を評価するための枠組みを提供します。一般に、すべての細胞株は、ハンギングドロップでスフェロイドを作成し、上皮に見える細胞株は、典型的には、定期的な球を形成しないことが見出されました。

<table>
	<tbody>
		<tr>
			<td>Matrigel Growth Factor Reduced</td>
			<td>Corning</td>
			<td>CB-40234</td>
			<td></td>
		</tr>
		<tr>
			<td>Collagen Type I, Rat Tail, 100 mg</td>
			<td>Millipore</td>
			<td>08-115</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>Life Technologies</td>
			<td>11995-065</td>
			<td></td>
		</tr>
		<tr>
			<td>RPMI 1640 Medium&#160;</td>
			<td>Life Technologies</td>
			<td>11875-093</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS</td>
			<td>Life Technologies</td>
			<td>10010-023</td>
			<td></td>
		</tr>
		<tr>
			<td>0.05% Trypsin-EDTA</td>
			<td>Life Technologies</td>
			<td>25300-054</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum, Heat Inactivated</td>
			<td>Omega Scientific</td>
			<td>FB-12</td>
			<td></td>
		</tr>
		<tr>
			<td>100mm TC-treated Dishes</td>
			<td>Corning Incorporated</td>
			<td>430167</td>
			<td></td>
		</tr>
		<tr>
			<td>24-well TC-treated Plates</td>
			<td>NEST Biotechnlology</td>
			<td>702001</td>
			<td></td>
		</tr>
		<tr>
			<td>Olympus IX-71 Inverted Microscope</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td colspan="4">Cell lines were maintained in DMEM + 10% FBS, with the expection of BT-474 and LNCaP cells, which were mantained in RPMI + 10% FBS.</td>
		</tr>
	</tbody>
</table>

a cancer cell spheroid assay to assess invasion in a 3d setting

The invasive nature of cancer cell lines is thought to correlate with their metastatic potential. Most traditional assays, however, do not examine these invasive features in a three-dimensional environment and the resulting data suffer from reduced biological applicability. Here an approach is presented to visualize the invasive ability of cell lines in a physiologically relevant setting. The cancer cell spheroid invasion assay first utilizes gravity to generate spheroids within drops of media that hang from the lid of a cell culture dish. Next, these spheroids are embedded in a 3D matrix consisting of a mixture of basement membrane materials and type I collagen. Cancer cell egression from the spheroids into the surrounding matrix is then monitored over time. The method described here can be modified to examine invasion after coculture of different cell types, inclusion of drugs/inhibitors, or alterations in extracellular matrix (ECM) constituents.

スフェロイド浸潤アッセイを用いた （図1）、癌細胞株のパネルは、同様に基底膜材料およびI型コラーゲンから成る3次元マトリクス状に移植後展示電池出口の量についてのスフェロイドを形成するそれらの能力について試験しました（ 表1）。これらの結果は、全ての癌細胞株は、 インビトロでの上皮形態を有する細胞株は、通常、滑らかな凝集...

Watch this Scientific Journal Video about A Cancer Cell Spheroid Assay to Assess Invasion in a 3D Setting at JoVE.com

A Cancer Cell Spheroid Assay to Assess Invasion in a 3D Setting

This method evaluates cancer cell invasion from spheroids into a surrounding 3D matrix. Spheroids are generated via the hanging drop culture method and then embedded in a matrix comprised of basement membrane materials and type I collagen. Invasion out of the spheroids is subsequently monitored.

3Dの設定で侵略を評価するために、癌細胞スフェロイドアッセイ

The invasive nature of cancer cell lines is thought to correlate with their metastatic potential.  Most traditional assays, however, do not examine these ...

a-cancer-cell-spheroid-assay-to-assess-invasion-in-a-3d-setting

Research

JoVE Journal

Medicine

32.3K ビュー.  Georgetown University. This method evaluates cancer cell invasion from spheroids into a surrounding 3D matrix. Spheroids are generated via the hanging drop culture method and then embedded in a matrix comprised of basement membrane materials and type I collagen. Invasion out of the spheroids is subsequently monitored. 

ビデオ: A Cancer Cell Spheroid Assay to Assess Invasion in a 3D Setting

A Real-time Electrical Impedance Based Technique to Measure Invasion of Endothelial Cell Monolayer by Cancer Cells

Metastatic dissemination of malignant cells requires degradation of basement membrane, attachment of tumor cells to vascular endothelium, retraction of endothelial junctions and finally invasion and migration of tumor cells through the endothelial layer to enter the bloodstream as a means of transport to distant sites in the host1-3. Once in the circulatory system, cancer cells adhere to capillary walls and extravasate to the surrounding tissue to form metastatic tumors4,5. The various components of tumor cell-endothelial cell interaction can be replicated in vitro by challenging a monolayer of human umbilical vein endothelial cells (HUVEC) with cancer cells. Studies performed with electron and phase-contrast microscopy suggest that the in vitro sequence of events fairly represent the in vivo metastatic process6. Here, we describe an electrical-impedance based technique that monitors and quantifies in real-time the invasion of endothelial cells by malignant tumor cells.
Giaever and Keese first described a technique for measuring fluctuations in impedance when a population of cells grow on the surface of electrodes7,8. The xCELLigence instrument, manufactured by Roche, utilizes a similar technique to measure changes in electrical impedance as cells attach and spread in a culture dish covered with a gold microelectrode array that covers approximately 80% of the area on the bottom of a well. As cells attach and spread on the electrode surface, it leads to an increase in electrical impedance9-12. The impedance is displayed as a dimensionless parameter termed cell-index, which is directly proportional to the total area of tissue-culture well that is covered by cells. Hence, the cell-index can be used to monitor cell adhesion, spreading, morphology and cell density.
The invasion assay described in this article is based on changes in electrical impedance at the electrode/cell interphase, as a population of malignant cells invade through a HUVEC monolayer (Figure 1). The disruption of endothelial junctions, retraction of endothelial monolayer and replacement by tumor cells lead to large changes in impedance. These changes directly correlate with the invasive capacity of tumor cells, i.e., invasion by highly aggressive cells lead to large changes in cell impedance and vice versa. This technique provides a two-fold advantage over existing methods of measuring invasion, such as boyden chamber and matrigel assays: 1) the endothelial cell-tumor cell interaction more closely mimics the in vivo process, and 2) the data is obtained in real-time and is more easily quantifiable, as opposed to end-point analysis for other methods.

This article describes an in vitro technique for monitoring cancer cells invading through a monolayer of endothelial cells. The data is acquired in real-time as a function of changes in impedance on the surface of electrodes at the well bottom.

癌細胞による内皮細胞単層の侵入を測定するリアルタイム電気インピーダンス基づく手法

Metastatic dissemination of malignant cells requires degradation of basement membrane, attachment of tumor cells to vascular endothelium, retraction of ...

医学

Multi-photon Imaging of Tumor Cell Invasion in an Orthotopic Mouse Model of Oral Squamous Cell Carcinoma

Loco-regional invasion of head and neck cancer is linked to metastatic risk and presents a difficult challenge in designing and implementing patient management strategies. Orthotopic mouse models of oral cancer have been developed to facilitate the study of factors that impact invasion and serve as model system for evaluating anti-tumor therapeutics. In these systems, visualization of disseminated tumor cells within oral cavity tissues has typically been conducted by either conventional histology or with in vivo bioluminescent methods. A primary drawback of these techniques is the inherent inability to accurately visualize and quantify early tumor cell invasion arising from the primary site in three dimensions. Here we describe a protocol that combines an established model for squamous cell carcinoma of the tongue (SCOT) with two-photon imaging to allow multi-vectorial visualization of lingual tumor spread. The OSC-19 head and neck tumor cell line was stably engineered to express the F-actin binding peptide LifeAct fused to the mCherry fluorescent protein (LifeAct-mCherry). Fox1nu/nu mice injected with these cells reliably form tumors that allow the tongue to be visualized by ex-vivo application of two-photon microscopy. This technique allows for the orthotopic visualization of the tumor mass and locally invading cells in excised tongues without disruption of the regional tumor microenvironment. In addition, this system allows for the quantification of tumor cell invasion by calculating distances that invaded cells move from the primary tumor site. Overall this procedure provides an enhanced model system for analyzing factors that contribute to SCOT invasion and therapeutic treatments tailored to prevent local invasion and distant metastatic spread. This method also has the potential to be ultimately combined with other imaging modalities in an in vivo setting.

A comprehensive overview of the techniques involved in generating a mouse model of oral cancer and quantitative monitoring of tumor invasion within the tongue through multi-photon microscopy of labeled cells is presented. This system can serve as a useful platform for the molecular assessment and drug efficacy of anti-invasive compounds.

口腔扁平上皮癌の同所性マウスモデルにおける腫瘍細胞の浸潤の多光子イメージング

Loco-regional invasion of head and neck cancer is linked to metastatic risk and presents a difficult challenge in designing and implementing patient ...

Spheroid Assay to Measure TGF-&#946;-induced Invasion

TGF-&beta; has opposing roles in breast cancer progression by acting as a tumor suppressor in the initial phase, but stimulating invasion and metastasis at later stage1,2. Moreover, TGF-&beta; is frequently overexpressed in breast cancer and its expression correlates with poor prognosis and metastasis 3,4. The mechanisms by which TGF-&beta; induces invasion are not well understood.
TGF-&beta; elicits its cellular responses via TGF-&beta; type II (T&beta;RII) and type I (T&beta;RI) receptors. Upon TGF-&beta;-induced heteromeric complex formation, T&beta;RII phosphorylates the T&beta;RI. The activated T&beta;RI initiates its intracellular canonical signaling pathway by phosphorylating receptor Smads (R-Smads), i.e. Smad2 and Smad3. These activated R-Smads form heteromeric complexes with Smad4, which accumulate in the nucleus and regulate the transcription of target genes5. In addition to the previously described Smad pathway, receptor activation results in activation of several other non-Smad signaling pathways, for example Mitogen Activated Protein Kinase (MAPK) pathways6.
To study the role of TGF-&beta; in different stages of breast cancer, we made use of the MCF10A cell system. This system consists of spontaneously immortalized MCF10A1 (M1) breast epithelial cells7, the H-RAS transformed M1-derivative MCF10AneoT (M2), which produces premalignant lesions in mice8, and the M2-derivative MCF10CA1a (M4), which was established from M2 xenografts and forms high grade carcinomas with the ability to metastasize to the lung9. This MCF10A series offers the possibility to study the responses of cells with different grades of malignancy that are not biased by a different genetic background.
For the analysis of TGF-&beta;-induced invasion, we generated homotypic MCF10A spheroid cell cultures embedded in a 3D collagen matrix in vitro (Fig 1). Such models closely resemble human tumors in vivo by establishing a gradient of oxygen and nutrients, resulting in active and invasive cells on the outside and quiescent or even necrotic cells in the inside of the spheroid10. Spheroid based assays have also been shown to better recapitulate drug resistance than monolayer cultures11. This MCF10 3D model system allowed us to investigate the impact of TGF-&beta; signaling on the invasive properties of breast cells in different stages of malignancy.

Spheroid Assay to Measure TGF-&amp;#946;-induced Invasion

An assay to quantitatively measure Transforming Growth Factor (TGF)-&#x03B2;-induced invasion in 3-dimensional collagen gels is described. This assay takes advantage of the MCF10A series of cell lines, which represent different stages of breast cancer development. This method can be adopted to be used with other cell lines and might be used to investigate other potential activators or inhibitors of invasion.

TGF -β誘発性浸潤を測定する回転楕円体アッセイ

TGF-&beta; has opposing roles in breast cancer progression by acting as a tumor suppressor in the initial phase, but stimulating invasion and metastasis ...

Modeling and Imaging 3-Dimensional Collective Cell Invasion

A defining characteristic of cancer malignancy is invasion and metastasis 1. In some cancers (e.g. glioma 2), local invasion into surrounding healthy tissue is the root cause of disease and death. For other cancers (e.g. breast, lung, etc.), it is the process of metastasis, in which tumor cells move from a primary tumor mass, colonize distal sites and ultimately contribute to organ failure, that eventually leads to morbidity and mortality 3. It has been estimated that invasion and metastasis are responsible for 90&#37; of cancer deaths 4. As a result, there has been intense interest in identifying the molecular processes and critical protein mediators of invasion and metastasis for the purposes of improving diagnosis and treatment 5.
A challenge for cancer scientists is to develop invasion assays that sufficiently resemble the in vivo situation to enable accurate disease modeling 6. Two-dimensional cell motility assays are only informative about one aspect of invasion and do not take into account extracellular matrix (ECM) protein remodeling which is also a critical element. Recently, research has refined our understanding of tumor cell invasion and revealed that individual cells may move by elongated or rounded modes 7. In addition, there has been greater appreciation of the contribution of collective invasion, in which cells invade in strands, sheets and clusters, particularly in highly differentiated tumors that maintain epithelial characteristics, to the spread of cancer 8.
We present a refined method 9 for examining the contributions of candidate proteins to collective invasion 10. In particular, by engineering separate pools of cells to express different fluorescent proteins, it is possible to molecularly dissect the activities and proteins required in leading cells versus those required in following cells. The use of RNAi provides the molecular tool to experimentally disassemble the processes involved in individual cell invasion as well as in different positions of collective invasion. In this procedure, mixtures of fluorescently-labeled cells are plated on the bottom of a Transwell insert previously filled with Matrigel ECM protein, then allowed to invade "upwards" through the filter and into the Matrigel. Reconstruction of z-series image stacks, obtained by confocal imaging, into three-dimensional representations allows for visualization of collectively invading strands and analysis of the representation of fluorescently-labeled cells in leading versus following positions.

Models of tumor cell invasion into three-dimensional extracellular matrix better reflect the in vivo situation than two-dimensional motility assays. Using matrix invasion assays combined with confocal imaging of fluorescently-labeled cells, detailed information on invasion modes and the distinct contributions of leading versus following cells can be obtained.

モデリングとイメージング、3次元の集団細胞浸潤

A defining characteristic of cancer malignancy is invasion and metastasis 1. In some cancers (e.g. glioma 2), local invasion into surrounding healthy ...

In vitro Mesothelial Clearance Assay that Models the Early Steps of Ovarian Cancer Metastasis

Ovarian cancer is the fifth leading cause of cancer related deaths in the United States1. Despite a positive initial response to therapies, 70 to 90 percent of women with ovarian cancer develop new metastases, and the recurrence is often fatal2. It is, therefore, necessary to understand how secondary metastases arise in order to develop better treatments for intermediate and late stage ovarian cancer. Ovarian cancer metastasis occurs when malignant cells detach from the primary tumor site and disseminate throughout the peritoneal cavity. The disseminated cells can form multicellular clusters, or spheroids, that will either remain unattached, or implant onto organs within the peritoneal cavity3 (Figure 1, Movie 1). 
All of the organs within the peritoneal cavity are lined with a single, continuous, layer of mesothelial cells4-6 (Figure 2). However, mesothelial cells are absent from underneath peritoneal tumor masses, as revealed by electron micrograph studies of excised human tumor tissue sections3,5-7 (Figure 2). This suggests that mesothelial cells are excluded from underneath the tumor mass by an unknown process. 
Previous in vitro experiments demonstrated that primary ovarian cancer cells attach more efficiently to extracellular matrix than to mesothelial cells8, and more recent studies showed that primary peritoneal mesothelial cells actually provide a barrier to ovarian cancer cell adhesion and invasion (as compared to adhesion and invasion on substrates that were not covered with mesothelial cells)9,10. This would suggest that mesothelial cells act as a barrier against ovarian cancer metastasis. The cellular and molecular mechanisms by which ovarian cancer cells breach this barrier, and exclude the mesothelium have, until recently, remained unknown. 
Here we describe the methodology for an in vitro assay that models the interaction between ovarian cancer cell spheroids and mesothelial cells in vivo (Figure 3, Movie 2). Our protocol was adapted from previously described methods for analyzing ovarian tumor cell interactions with mesothelial monolayers8-16, and was first described in a report showing that ovarian tumor cells utilize an integrin &#x2013;dependent activation of myosin and traction force to promote the exclusion of the mesothelial cells from under a tumor spheroid17. This model takes advantage of time-lapse fluorescence microscopy to monitor the two cell populations in real time, providing spatial and temporal information on the interaction. The ovarian cancer cells express red fluorescent protein (RFP) while the mesothelial cells express green fluorescent protein (GFP). RFP-expressing ovarian cancer cell spheroids attach to the GFP-expressing mesothelial monolayer. The spheroids spread, invade, and force the mesothelial cells aside creating a hole in the monolayer. This hole is visualized as the negative space (black) in the GFP image. The area of the hole can then be measured to quantitatively analyze differences in clearance activity between control and experimental populations of ovarian cancer and/ or mesothelial cells. This assay requires only a small number of ovarian cancer cells (100 cells per spheroid X 20-30 spheroids per condition), so it is feasible to perform this assay using precious primary tumor cell samples. Furthermore, this assay can be easily adapted for high throughput screening.

In vitro Mesothelial Clearance Assay that Models the Early Steps of Ovarian Cancer Metastasis

The mesothelial clearance assay described here takes advantage of fluorescently labeled cells and time-lapse video microscopy to visualize and quantitatively measure the interactions of ovarian cancer multicellular spheroids and mesothelial cell monolayers. This assay models the early steps of ovarian cancer metastasis.

in vitroで中皮クリアランスアッセイでそのモデルの卵巣がんの転移の初期段階を

Ovarian cancer is the fifth leading cause of cancer related deaths in the United States1. Despite a positive initial response to therapies, 70 to 90 ...

Quantification of Breast Cancer Cell Invasiveness Using a Three-dimensional (3D) Model

It is now well known that the cellular and tissue microenvironment are critical regulators influencing tumor initiation and progression. Moreover, the extracellular matrix (ECM) has been demonstrated to be a critical regulator of cell behavior in culture and homeostasis in vivo. The current approach of culturing cells on two-dimensional (2D), plastic surfaces results in the disturbance and loss of complex interactions between cells and their microenvironment. Through the use of three-dimensional (3D) culture assays, the conditions for cell-microenvironment interaction are established resembling the in vivo microenvironment. This article provides a detailed methodology to grow breast cancer cells in a 3D basement membrane protein matrix, exemplifying the potential of 3D culture in the assessment of cell invasion into the surrounding environment. In addition, we discuss how these 3D assays have the potential to examine the loss of signaling molecules that regulate epithelial morphology by immunostaining procedures. These studies aid to identify important mechanistic details into the processes regulating invasion, required for the spread of breast cancer.

Quantification of Breast Cancer Cell Invasiveness Using a Three-dimensional 3D Model

This article provides detailed methodologies for the use of three-dimensional (3D) assays to quantify breast cancer cell invasion. Specifically, we discuss the procedures required to set up such assays, quantification, and data analysis, as well as methods to examine the loss of membrane integrity that occurs when cells invade.

3次元（3D）モデルを用いた乳癌細胞浸潤の定量化

It is now well known that the cellular and tissue microenvironment are critical regulators influencing tumor initiation and progression. Moreover, the ...

A Modified In vitro Invasion Assay to Determine the Potential Role of Hormones, Cytokines and/or Growth Factors in Mediating Cancer Cell Invasion

Blood serum serves as a chemoattractant towards which cancer cells migrate and invade, facilitating their intravasation into microvessels. However, the actual molecules towards which the cells migrate remain elusive. This modified invasion assay has been developed to identify targets which drive cell migration and invasion. This technique compares the invasion index under three conditions to determine whether a specific hormone, growth factor, or cytokine plays a role in mediating the invasive potential of a cancer cell. These conditions include i) normal fetal bovine serum (FBS), ii) charcoal-stripped FBS (CS-FBS), which removes hormones, growth factors, and cytokines and iii) CS-FBS + molecule (denoted &#8220;X&#8221;). A significant change in cell invasion with CS-FBS as compared to FBS, indicates the involvement of hormones, cytokines or growth factors in mediating the change. Individual molecules can then be added back to CS-FBS to assay their ability to reverse or rescue the invasion phenotype. Furthermore, two or more factors can be combined to evaluate the additive or synergistic effects of multiple molecules in driving or inhibiting invasion. Overall, this method enables the investigator to determine whether hormones, cytokines, and/or growth factors play a role in cell invasion by serving as chemoattractants or inhibitors of invasion for a particular type of cancer cell or a specific mutant. By identifying specific chemoattractants and inhibitors, this modified invasion assay may help to elucidate signaling pathways that direct cancer cell invasion.

A Modified In vitro Invasion Assay to Determine the Potential Role of Hormones, Cytokines and/or Growth Factors in Mediating Cancer Cell Invasion

This video article describes a modified in vitro method to examine the role of hormones, cytokines and/or growth factors in driving cancer cell invasion.

変更された<em&gt;インビトロ</em媒介する癌細胞浸潤におけるホルモン、サイトカインおよび/または成長因子の潜在的な役割を決定するために&gt;浸潤アッセイ

Blood serum serves as a chemoattractant towards which cancer cells migrate and invade, facilitating their intravasation into microvessels. However, the ...

Assessment of Ovarian Cancer Spheroid Attachment and Invasion of Mesothelial Cells in Real Time

Ovarian cancers metastasize by shedding into the peritoneal fluid and dispersing to distal sites within the peritoneum. Monolayer cultures do not accurately model the behaviors of cancer cells within a nonadherent environment, as cancer cells inherently aggregate into multicellular structures which contribute to the metastatic process by attaching to and invading the peritoneal lining to form secondary tumors. To model this important stage of ovarian cancer metastasis, multicellular aggregates, or spheroids, can be generated from established ovarian cancer cell lines maintained under nonadherent conditions. To mimic the peritoneal microenvironment encountered by tumor cells in vivo, a spheroid-mesothelial co-culture model was established in which preformed spheroids are plated on top of a human mesothelial cell monolayer, formed over an extracellular matrix barrier. Methods were then developed using a real-time cell analyzer to conduct quantitative real time measurements of the invasive capacity of different ovarian cancer cell lines grown as spheroids. This approach allows for the continuous measurement of invasion over long periods of time, which has several advantages over traditional endpoint assays and more laborious real time microscopy image analyses. In short, this method enables a rapid, determination of factors which regulate the interactions between ovarian cancer spheroid cells invading through mesothelial and matrix barriers over time.

Ovarian cancer cell invasion into the mesothelial lining of the peritoneum is a dynamic process over time. Utilizing a real time analyzer, the invasive capacity of ovarian cancer cells in a spheroid-mesothelial cell co-culture model can be quantified over prolonged time periods, providing insights into factors regulating the metastatic process.

リアルタイムで中皮細胞の卵巣癌スフェロイドアタッチメントおよび浸潤の評価

Ovarian cancers metastasize by shedding into the peritoneal fluid and dispersing to distal sites within the peritoneum. Monolayer cultures do not ...

Focus Formation: A Cell-based Assay to Determine the Oncogenic Potential of a Gene

Malignant transformation of cells is typically associated with increased proliferation, loss of contact inhibition, acquisition of anchorage-independent growth potential, and the ability to form tumors in experimental animals1. In NIH 3T3 cells, the Ras signal transduction pathway is known to trigger many of these events, what is known as Ras transformation. The introduction of an overexpressed gene in NIH 3T3 cells may promote morphological transformation and loss of contact inhibition, which can help determine the oncogenic potential of that gene of interest. An assay that provides a straightforward method to assess one aspect of the transforming potential of an oncogene is the Focus Formation Assay (FFA)2. When NIH 3T3 cells divide normally in culture, they do so until they reach a confluent monolayer. However, in the presence of an overexpressed oncogene, these cells can begin to grow in dense, multilayered foci1 that can be visualized and quantified by crystal violet or Hema 3 staining. In this article we describe the FFA protocol with retroviral transduction of the gene of interest into NIH 3T3 cells, and how to quantify the number of foci through staining. Retroviral transduction offers a more efficient method of gene delivery than transfection, and the use of an ecotropic murine retrovirus provides a biosafety control when working with potential human oncogenes.

The Focus Formation Assay provides a straightforward method to assess the transforming potential of a candidate oncogene.

フォーカス形成：細胞ベースのアッセイ遺伝子の発癌性を決定するために、

Malignant transformation of cells is typically associated with increased proliferation, loss of contact inhibition, acquisition of anchorage-independent ...

Carotid Artery Infusions for Pharmacokinetic and Pharmacodynamic Analysis of Taxanes in Mice

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study model. As the use of mouse models are often a vital step in preclinical drug discovery and drug development1-8, it is necessary to design a system to introduce drugs into mice in a uniform, reproducible manner. Ideally, the system should permit the collection of blood samples at regular intervals over a set time course. The ability to measure drug concentrations by mass-spectrometry, has allowed investigators to follow the changes in plasma drug levels over time in individual mice1, 9, 10. In this study, paclitaxel was introduced into transgenic mice as a continuous arterial infusion over three hours, while blood samples were simultaneously taken by retro-orbital bleeds at set time points. Carotid artery infusions are a potential alternative to jugular vein infusions, when factors such as mammary tumors or other obstructions make jugular infusions impractical. Using this technique, paclitaxel concentrations in plasma and tissue achieved similar levels as compared to jugular infusion. In this tutorial, we will demonstrate how to successfully catheterize the carotid artery by preparing an optimized catheter for the individual mouse model, then show how to insert and secure the catheter into the mouse carotid artery, thread the end of the catheter out through the back of the mouse&#8217;s neck, and hook the mouse to a pump to deliver a controlled rate of drug influx. Multiple low volume retro-orbital bleeds allow for analysis of plasma drug concentrations over time.

This method was developed with the goal of delivering a steady drug solution via the carotid artery, to assess the pharmacokinetics of novel drugs in mouse models.

マウスにおけるタキサンの薬物動態学的および薬力学的分析のための頸動脈煎茶

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study ...