我们感谢实验室成员的有益讨论和支持。我们对乳腺癌干细胞和肿瘤微环境的研究由加拿大癌症研究学会研究所和美国陆军国防部乳腺癌计划（赠款#BC160912）资助。V.B.由西部博士后奖学金（西部大学）支持，A.L.A.和V.B.都得到加拿腺癌协会的支持。C.L.得到了加拿大政府颁发的Vanier加拿大研究生奖学金的支持。

作者没有什么可透露的。

乳腺癌转移和对治疗的抵抗已成为全世界妇女死亡的主要原因。乳腺癌干细胞（BCSC）亚群的存在有助于增强转移26，43，44，45，46和治疗耐药性21，47，48。因此，未来治疗的重点应旨在根除BCSC以达到更好的治疗效果，这需要使用体外和体内方法分离和表征BCSC功能特征的准确方法。
源自不同亚型乳腺癌的永生化细胞系已被证明是研究乳腺癌生物学的可行模型，包括BCSCs的分离和表征26，49，50。细胞系的高增殖能力和无限扩增能力为进行高度可重复且技术简单的研究提供了理想的模型系统。然而，由于细胞系的克隆起源，它们可能无法概括不同患者和/或肿瘤组织内癌细胞所表现出的异质性。此外，遗传改变可以在细胞系的连续传代过程中获得，并可能诱导基因型或表型变化，从而混淆实验结果51。相比之下，原代患者来源的细胞尽管增殖和扩增能力有限，但可以提供比体内观察到的更准确的模型。然而，这些样品可能更难获得，并且在技术上更具挑战性。在选择用于分离和表征BCSC的起始模型系统时，应考虑所有这些因素。
FACS是一种常用的技术，用于基于细胞表面标志物表达52，53分离感兴趣的细胞。基于细胞表面抗原（CD44 和 CD24）和 ALDH 酶活性，可以从乳腺癌细胞系和肿瘤组织中分离出高纯度的人 BCSC1，2。分选效率决定了分选样品的纯度，建议用户分析一小部分用活性染料孵育的分选样品，以检查分选效率53，54。分选效率可能受到许多因素的影响，包括细胞团块的存在、大量死亡或垂死的细胞、荧光染料补偿不当和/或在预分选解离步骤中由于对胰蛋白酶或胶原酶的敏感性而导致细胞表面抗原受损53，54，55，56.因此，产生适当的单细胞悬液并使用适当的细胞解离技术将提高分选效率。在进行多参数细胞分选时，选择能够最大限度地减少光谱重叠的荧光染料非常重要。在某些情况下，在无法避免光谱重叠的情况下，应使用包含除一种（荧光减一，FMO）以外的所有荧光染料的对照，以尽量减少荧光信号溢出到其他通道54。或者，可以通过在最终FACS分离感兴趣的细胞56之前免疫磁分离细胞群来减少光谱重叠。
体外测定，例如本协议中描述的集落形成和乳腺球测定已被广泛用于研究BCSCs的自我更新和增殖能力57，58，59，60，61，62。此外，这些测定可用于评估不同治疗药物对BCSC功能的活性。在BCSC维持63中已经实施了几种进化保守的信号通路，并且集落形成64，65，66和乳腺球测定64，67都用于评估这些途径的治疗破坏作为阻断BCSC内在信号传导和减少BCSC活性和疾病进展的干预措施的价值。由于细胞密度低、样品之间的差异以及缺乏对分离体外条件的适应性，使用原代细胞进行集落形成测定可能具有挑战性。这些挑战可以通过在软琼脂层上培养BCSC或在胶原包被的细胞培养皿上与成纤维细胞共培养来克服68，69，70。此外，在培养基中补充生长因子（如FGF771）也可以提高从组织样品中分离的细胞的集落形成能力。此外，在单细胞悬液生成步骤中使用胶原酶或胰蛋白酶过度消化组织会导致集落形成能力低至零，并降低乳腺球形成效率31。在这两种测定中，应注意孵育检测板不受干扰，以避免在形成时破坏菌落或球体结构。还建议用户延长原代细胞的孵育期（相对于细胞系），因为这些细胞形成集落或球体可能需要更长的时间。
多条证据线已经证明了细胞外基质（ECM）15，17，72和基质成分（如成纤维细胞，免疫细胞，内皮细胞和脂肪细胞）在影响BCSC功能方面的关键作用15。因此，我们在本协议中描述的3D培养模型可以提供有用的实验系统，以帮助在体外环境中概括体内肿瘤微环境。尽管3D培养系统与癌症患者的肿瘤微环境非常相似，但长期维持细胞作为类器官可能很困难。此外，优化3D培养条件以及准确研究BCSC的自我更新和分化能力的能力具有挑战性73。在3D培养系统中形成的类器官的效率取决于培养基中补充的生长因子74。缺乏关键成分（例如ROCK抑制剂）可能导致类器官形成减少或没有74。培养基应每 3-4 天补充一次，以维持最佳细胞功能和培养的可持续性。为了概括体内条件和反应，在任何类型的外源性处理之前让细胞形成类器官始终很重要75。来自患者样本的细胞应给予足够的时间来形成类器官，特别是如果目标是评估药物反应75。
虽然这些体外方法是表征BCSC功能的有吸引力且易于访问的实验工具，但肿瘤异质性和肿瘤微环境对BCSC行为的影响无法完全有效地研究。因此，在可行的情况下，这些体外测定应与体内异种移植模型相辅相成，以进一步验证与BSCS生物学和/或对新疗法的反应相关的实验结果。不同的体内模型已经用于研究BCSC的致瘤性和转移性。异位（皮下植入）和原位（MFP植入）小鼠模型已被用于产生乳腺肿瘤并评估肿瘤生长随时间的纵向变化50。尽管两种体内注射方法都可用于研究BCSC生物学，但MFP的天然基质和脉管系统相关成分允许更准确地概括在患者中观察到的原发性乳腺肿瘤进展，因此MFP注射是优选的76，77，78。最后，需要使用免疫功能低下的小鼠来植入人类BCSC和肿瘤生长，这阻止了免疫细胞在肿瘤发生和转移研究中的作用79。最近，这一限制已通过使用人源化小鼠得到解决，其中在异种移植研究开始之前通过骨髓移植重建人类免疫系统80，81，82。然而，这些模型价格昂贵且技术上具有挑战性，因此仍然不常用83。
总之，这里我们提供了一种从乳腺癌细胞系和患者来源的肿瘤组织样本中分离人类BCSC的方案。我们还描述了可用于研究BCSC功能的下游测定的 体外 和 体内 方案，能够针对不同的乳腺癌细胞来源进行优化，并且可以灵活地在不同的实验条件下进行。这些方案将对癌症干细胞，乳腺癌生物学和治疗开发感兴趣的研究人员有用，最终目标是改善未来的患者预后。

了解人类乳腺癌干细胞（BCSC）的细胞和分子机制对于解决乳腺癌治疗中遇到的挑战至关重要。BCSC概念的出现可以追溯到21世纪初，当时发现少量CD44 + CD24-/低乳腺癌细胞能够在小鼠中产生异质肿瘤1，2。随后，观察到具有高酶活性的醛脱氢酶（ALDH高）的人乳腺癌细胞也表现出类似的干细胞样性质3。这些BCSC代表能够自我更新和分化的细胞群，有助于本体肿瘤的异质性1，2，3。越来越多的证据表明，进化保守信号通路的改变推动了BCSC的存活和维持4，5，6，7，8，9，10，11，12，13，14.此外，细胞外在微环境已被证明在决定不同的BCSC功能中起着关键作用15，16，17。这些分子途径和调节BCSC功能的外部因素有助于乳腺癌复发，转移18和对治疗耐药性的发展19，20，21，治疗后BCSC的残留存在对乳腺癌患者的总体生存构成重大挑战22，23.因此，这些因素的临床前评估对于确定BCSC靶向疗法非常重要，这些疗法可能有利于实现更好的治疗结果和提高乳腺癌患者的总生存期。
几种体外人乳腺癌细胞系模型和体内人异种移植模型已被用于表征BCSCs24，25，26，27，28，29。细胞系在每次连续传代后不断重新填充的能力使其成为进行基于组学和药物基因组学研究的理想模型系统。然而，细胞系通常无法概括在患者样本中观察到的异质性。因此，用患者来源的样本补充细胞系数据非常重要。以最纯净的形式分离BCSC对于实现BCSC的详细表征非常重要。 实现这种纯度取决于BCSC特有的表型标记的选择。 目前，ALDH高CD44+CD24- 细胞表型最常用于使用荧光活化细胞分选 （FACS） 从大量乳腺癌细胞群中区分和分离人 BCSC，以获得最大纯度1，3，26.此外，可以使用体外和体内技术评估分离的BCSCs的特性，例如自我更新，增殖和分化。
例如，体外集落形成测定可用于评估单个细胞在不同治疗条件下自我更新以形成50个或更多细胞集落的能力30。乳腺球测定也可用于评估乳腺癌细胞在锚定非依赖条件下的自我更新潜力。该测定法测量单细胞在无血清非贴壁培养条件下每次连续传代时以球体（BCSC 和非 BCSC 的混合物）生成和生长的能力31。此外，三维（3D）培养模型可用于评估BCSC功能，包括细胞-细胞和细胞-基质相互作用，这些相互作用密切概括了体内微环境，并允许研究潜在的BCSC靶向疗法的活性32。尽管体外模型的应用多种多样，但仅使用体外测定很难模拟体内条件的复杂性。这一挑战可以通过使用小鼠异种移植模型来评估体内BCSC行为来克服。特别是，这些模型可作为评估乳腺癌转移33，研究疾病进展期间与微环境的相互作用34，体内成像35以及预测患者特异性毒性和抗肿瘤药物功效的理想系统34。
该协议详细描述了从大量异质乳腺癌细胞群中以最大纯度分离人ALDH高CD44 + CD24-BCSC。我们还详细介绍了三种体外技术（集落形成测定、乳腺球测定和 3D 培养模型）和可用于评估 BCSC 不同功能的体内肿瘤异种移植测定。这些方法适合于有兴趣从人类乳腺癌细胞系或原发性患者来源的乳腺癌细胞和肿瘤组织中分离和表征BCSC的研究人员使用，以了解BCSC生物学和/或研究新的BCSC靶向疗法。

<table>
	<tbody>
		<tr>
			<td>7-Aminoactinomycin D (7AAD)</td>
			<td>BD</td>
			<td>51-68981E</td>
			<td>suggested: 0.25 &#181;g/1x106 cells</td>
		</tr>
		<tr>
			<td>Acetone</td>
			<td>Fisher</td>
			<td>A18-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Aldehyde dehydrogenase (ALDH) substrate</td>
			<td>Stemcell Technologies</td>
			<td>1700</td>
			<td>Sold commerically as part of the ALDEFLOUR Assay kit; follow manufacturer&#39;s instructions for ALDH substrate preparation</td>
		</tr>
		<tr>
			<td>Basement membrane extract (BME)</td>
			<td>Corning</td>
			<td>354234</td>
			<td>Sold under the commercial name Matrigel</td>
		</tr>
		<tr>
			<td>Cell culture plates: 6 well</td>
			<td>Corning</td>
			<td>877218</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell culture plates: 60mm</td>
			<td>Corning</td>
			<td>353002</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell culture plates: 96-well ultra low attachment</td>
			<td>Corning</td>
			<td>3474</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell strainer: 40 micron</td>
			<td>BD</td>
			<td>352340</td>
			<td></td>
		</tr>
		<tr>
			<td>Collagen</td>
			<td>Stemcell Technologies</td>
			<td>7001</td>
			<td>Prepare 1:30 dilution of 3 mg/mL collagen in PBS</td>
		</tr>
		<tr>
			<td>Collagenase</td>
			<td>Sigma</td>
			<td>11088807001</td>
			<td>1x</td>
		</tr>
		<tr>
			<td>Conical tubes: 50 mL</td>
			<td>Fisher scientific</td>
			<td>05-539-7</td>
			<td></td>
		</tr>
		<tr>
			<td>Crystal violet</td>
			<td>Sigma</td>
			<td>C6158</td>
			<td>Use 0.05% crystal violet solution in water for staining</td>
		</tr>
		<tr>
			<td>Dispase</td>
			<td>Stemcell Technologies</td>
			<td>7913</td>
			<td>5U/mL</td>
		</tr>
		<tr>
			<td>DMEM:F12</td>
			<td>Gibco</td>
			<td>11330-032</td>
			<td>1x, With L-glutamine and 15 mM HEPES</td>
		</tr>
		<tr>
			<td>DNAse</td>
			<td>Sigma</td>
			<td>D5052</td>
			<td>0.1 mg/mL final concentration</td>
		</tr>
		<tr>
			<td>FBS</td>
			<td>Avantor Seradigm Lifescience</td>
			<td>97068-085</td>
			<td>&#160;</td>
		</tr>
		<tr>
			<td>Flow tubes: 5ml</td>
			<td>BD</td>
			<td>352063</td>
			<td>Polypropylene round-bottom tubes</td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>Fisher</td>
			<td>84124</td>
			<td></td>
		</tr>
		<tr>
			<td>mouse anti-Human CD24 antibody</td>
			<td>BD</td>
			<td>561646</td>
			<td>R-phycoerythrin and Cyanine dye conjugated Clone: ML5</td>
		</tr>
		<tr>
			<td>mouse anti-Human CD44 antibody</td>
			<td>BD</td>
			<td>555479</td>
			<td>R-phycoerythrin conjugated, Clone: G44-26</td>
		</tr>
		<tr>
			<td>N,N-diethylaminobenzaldehyde (DEAB)</td>
			<td>Stemcell Technologies</td>
			<td>1700</td>
			<td>Sold commerically as part of the ALDEFLOUR Assay kit; follow manufacturer&#39;s instructions DEAB preparation</td>
		</tr>
		<tr>
			<td>PBS</td>
			<td>Wisent Inc</td>
			<td>311-425-CL</td>
			<td>1x, Without calcium and magnesium</td>
		</tr>
		<tr>
			<td>Trypsin-EDTA</td>
			<td>Gibco</td>
			<td>25200-056</td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Mammosphere Media Composition</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>B27</td>
			<td>Gibco</td>
			<td>17504-44</td>
			<td>1x</td>
		</tr>
		<tr>
			<td>bFGF</td>
			<td>Sigma</td>
			<td>F2006</td>
			<td>10 ng/mL</td>
		</tr>
		<tr>
			<td>BSA</td>
			<td>Bioshop</td>
			<td>ALB003</td>
			<td>04%</td>
		</tr>
		<tr>
			<td>DMEM:F12</td>
			<td>Gibco</td>
			<td>11330-032</td>
			<td>1x, With L-glutamine and 15 mM HEPES</td>
		</tr>
		<tr>
			<td>EGF</td>
			<td>Sigma</td>
			<td>E9644</td>
			<td>20 ng/mL</td>
		</tr>
		<tr>
			<td>Insulin</td>
			<td>Sigma</td>
			<td>16634</td>
			<td>5 &#181;g/mL</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>3D Organoid Media Composition</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>A8301</td>
			<td>Tocris</td>
			<td>2939</td>
			<td>500 nM</td>
		</tr>
		<tr>
			<td>B27</td>
			<td>Gibco</td>
			<td>17504-44</td>
			<td>1x</td>
		</tr>
		<tr>
			<td>DMEM:F12</td>
			<td>Gibco</td>
			<td>11330-032</td>
			<td>1x, With L-glutamine and 15 mM HEPES</td>
		</tr>
		<tr>
			<td>EGF</td>
			<td>Sigma</td>
			<td>E9644</td>
			<td>5 ng/mL</td>
		</tr>
		<tr>
			<td>FGF10</td>
			<td>Peprotech</td>
			<td>100-26</td>
			<td>20 ng/mL</td>
		</tr>
		<tr>
			<td>FGF7</td>
			<td>Peprotech</td>
			<td>100-19</td>
			<td>5 ng/mL</td>
		</tr>
		<tr>
			<td>GlutaMax</td>
			<td>Invitrogen</td>
			<td>35050-061</td>
			<td>1x</td>
		</tr>
		<tr>
			<td>HEPES</td>
			<td>Gibco</td>
			<td>15630-080</td>
			<td>10 mM</td>
		</tr>
		<tr>
			<td>N-acetylcysteine</td>
			<td>Sigma</td>
			<td>A9165</td>
			<td>1.25 mM</td>
		</tr>
		<tr>
			<td>Neuregulin &#946;1</td>
			<td>Peprotech</td>
			<td>100-03</td>
			<td>5 nM</td>
		</tr>
		<tr>
			<td>Nicotinamide</td>
			<td>Sigma</td>
			<td>N0636</td>
			<td>5 mM</td>
		</tr>
		<tr>
			<td>Noggin</td>
			<td>Peprotech</td>
			<td>120-10C</td>
			<td>100 ng/mL</td>
		</tr>
		<tr>
			<td>R-spondin3</td>
			<td>R&#38;D</td>
			<td>3500</td>
			<td>250 ng/mL</td>
		</tr>
		<tr>
			<td>SB202190</td>
			<td>Sigma</td>
			<td>S7067</td>
			<td>500 nM</td>
		</tr>
		<tr>
			<td>Y-27632</td>
			<td>Tocris</td>
			<td>1254</td>
			<td>5 &#181;M</td>
		</tr>
	</tbody>
</table>

isolation and functional assessment of human breast cancer stem cells from cell and tissue samples

乳腺癌干细胞（BCSC）是具有遗传或获得性干细胞样特征的癌细胞。尽管它们的频率很低，但它们是乳腺癌发生、复发、转移和治疗耐药性的主要贡献者。了解乳腺癌干细胞的生物学必须确定治疗乳腺癌的新治疗靶点。乳腺癌干细胞是根据独特的细胞表面标志物（如CD44、CD24）和醛脱氢酶（ALDH）的酶活性）的表达进行分离和表征的。这些 ALDH高CD44+CD24- 细胞构成了 BCSC 群体，可通过荧光激活细胞分选 （FACS） 进行下游功能研究。根据科学问题，可以使用不同的 体外 和 体内 方法来评估BCSC的功能特征。在这里，我们提供了一个详细的实验方案，用于从乳腺癌细胞的异质群体以及从乳腺癌患者获得的原发性肿瘤组织中分离人类BCSC。此外，我们还重点介绍了下游体 外 和 体内 功能测定，包括集落形成测定、乳腺球测定、3D 培养模型和可用于评估 BCSC 功能的肿瘤异种移植测定。

所描述的方案允许从异质的乳腺癌细胞群中分离人BCSC，无论是来自细胞系还是从解离的肿瘤组织中。对于任何给定的细胞系或组织样品，产生均匀的单细胞悬液以最大纯度分离BCSC至关重要，因为污染的非BCSC群体可能导致不同的细胞反应，特别是如果研究目的是评估靶向BCSC的治疗剂的功效。 应用严格的分选策略将最大限度地减少污染非BCSC的存在，并导致收集乳腺癌细胞比例的能力具有干细胞样特征，显示出将它们与大量癌细胞区分开来的细胞表型。表现出增强的 ALDH 酶活性、表达高水平的细胞表面标志物 CD44 和低/阴性表达的 CD24 的人乳腺癌细胞具有 ALDH高CD44+CD24- 表型，可归类为 BCSC。散装群体中BCSC的比例可能因细胞系或患者而异（图2），并且通常取决于疾病阶段，更具侵袭性的乳腺癌通常显示更高比例的BCSCs26，36，37。
分离的BCSC可用于进行不同的 体外 和 体内 测定，其中其行为和功能可以与大量和/或非BCSC群体的行为和功能进行比较。例如，单个乳腺癌细胞自我更新和产生50个细胞集落的能力可以通过集落形成测定来评估（图3A）。BCSC在锚地无关的实验条件下自我更新的能力可以通过乳球测定进行评估，其中可以分析可变球体数量，大小和球起始能力，并与BCSC的存在和功能相关联（图3B）。确定不同乳腺癌细胞系或乳腺肿瘤样本的接种细胞密度以获得最佳结果非常重要。这在进行SLDA时尤其重要，因为较高的细胞密度可能导致细胞聚集，从而导致对细胞活动的误解。
在BME中培养乳腺癌细胞允许BCSC形成3D结构，概括 体内 条件（图3C）。在其他微环境细胞类型（如成纤维细胞、内皮细胞和/或免疫细胞）存在下对乳腺癌细胞进行 3D 培养，具有研究微环境在 BCSC 3D 生长中的作用的额外能力38，39。生成3D类器官所需的特定细胞数量可能因细胞系或患者肿瘤来源而异，因此在任何大规模实验之前优化培养条件和细胞数量非常重要。
最后，体内小鼠异种移植模型可用于了解与非BCSC或大细胞群相比，BCSC在体内的生长（图4）自我更新，分化和/或肿瘤起始能力的差异。通常，在存在外源性因子或治疗剂的情况下观察到的体外细胞反应不代表体内环境，这表明体外观察应尽可能与体内研究相辅相成。使用体内异种移植模型，保留了细胞异质性和肿瘤结构，因此这些模型可以作为密切模拟人类患者微环境的系统。体内可以进行LDA以确定给定混合癌细胞群（BCSC或非BCSC）中肿瘤起始细胞的比例40，41。应优化使用的细胞稀释范围，并将取决于目标细胞群中启动细胞的频率。理想情况下，这些稀释液应包括导致100%肿瘤形成的剂量，低至没有肿瘤形成的细胞剂量，并且在两者之间有一个合理的范围。原发样本中肿瘤起始细胞的频率可能是可变的，并且在乳腺肿瘤具有非常少的数量或肿瘤起始细胞群异质的情况下，进行LDA可能特别具有挑战性42。在这些情况下，注射大量细胞更适合理解乳腺癌生物学。
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/61775/61775fig04.jpg"> 图 4:用于评估 BCSC 功能的体内异种移植测定。如图1所示，通过FACS分离MDA-MB-231乳腺癌细胞，并按照方案第9.1至9.8节（5 x 105细胞/小鼠;4只小鼠/细胞群）所述注射到雌性NSG小鼠的右胸乳脂垫中。显示原发性乳腺肿瘤生长动力学适用于 ALDHhi CD44+CD24- （■） 人群与 ALDH 低 CD44低/-CD24+ （□） 人群。数据表示为±平均值 S.E.M. * = 肿瘤大小与同一时间点各自的 ALDH 低 CD44低/-亚群显著不同（P < 0.05）。这个数字改编自克罗克等人26。<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/61775/61775fig04large.jpg" target="_blank">请点击此处查看此图的大图。</a>

Watch this Scientific Journal Video about Isolation and Functional Assessment of Human Breast Cancer Stem Cells from Cell and Tissue Samples at JoVE.com

Isolation and Functional Assessment of Human Breast Cancer Stem Cells from Cell and Tissue Samples

该实验方案描述了从乳腺癌细胞和组织样品中分离BCSC以及可用于评估BCSC表型和功能的 体外 和 体内 测定。

从细胞和组织样本中分离和功能评估人类乳腺癌干细胞

Breast cancer stem cells (BCSCs) are cancer cells with inherited or acquired stem cell-like characteristics. Despite their low frequency, they are major ...

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Research

JoVE Journal

Cancer Research

4.3K 次观看.  London Regional Cancer Program. 该实验方案描述了从乳腺癌细胞和组织样品中分离BCSC以及可用于评估BCSC表型和功能的 体外 和 体内 测定。

视频: Isolation and Functional Assessment of Human Breast Cancer Stem Cells from Cell and Tissue Samples

Establishment of Cancer Stem Cell Cultures from Human Conventional Osteosarcoma

The current improvements in therapy against osteosarcoma (OS) have prolonged the lives of cancer patients, but the survival rate of five years remains poor when metastasis has occurred. The Cancer Stem Cell (CSC) theory holds that there is a subset of tumor cells within the tumor that have stem-like characteristics, including the capacity to maintain the tumor and to resist multidrug chemotherapy. Therefore, a better understanding of OS biology and pathogenesis is needed in order to advance the development of targeted therapies to eradicate this particular subset and to reduce morbidity and mortality among patients. Isolating CSCs, establishing cell cultures of CSCs, and studying their biology are important steps to improving our understanding of OS biology and pathogenesis. The establishment of human-derived OS-CSCs from biopsies of OS has been made possible using several methods, including the capacity to create 3-dimensional stem cell cultures under nonadherent conditions. Under these conditions, CSCs are able to create spherical floating colonies formed by daughter stem cells; these colonies are termed &#34;cellular spheres&#34;. Here, we describe a method to establish CSC cultures from primary cell cultures of conventional OS obtained from OS biopsies. We clearly describe the several passages required to isolate and characterize CSCs.

The presence of cancer stem cells (CSCs) in bone sarcomas has recently been linked to their pathogenesis. In this article, we present the isolation of CSCs from primary cell cultures obtained from human biopsies of conventional osteosarcoma (OS) using the ability of CSCs to grow under nonadherent conditions.

巨蟹座的建立源于人类传统的骨肉瘤细胞培养

The current improvements in therapy against osteosarcoma (OS) have prolonged the lives of cancer patients, but the survival rate of five years remains ...

科研

癌症研究

Utilizing Functional Genomics Screening to Identify Potentially Novel Drug Targets in Cancer Cell Spheroid Cultures

The identification of functional driver events in cancer is central to furthering our understanding of cancer biology and indispensable for the discovery of the next generation of novel drug targets. It is becoming apparent that more complex models of cancer are required to fully appreciate the contributing factors that drive tumorigenesis in vivo and increase the efficacy of novel therapies that make the transition from pre-clinical models to clinical trials.
Here we present a methodology for generating uniform and reproducible tumor spheroids that can be subjected to siRNA functional screening. These spheroids display many characteristics that are found in solid tumors that are not present in traditional two-dimension culture. We show that several commonly used breast cancer cell lines are amenable to this protocol. Furthermore, we provide proof-of-principle data utilizing the breast cancer cell line BT474, confirming their dependency on amplification of the epidermal growth factor receptor HER2 and mutation of phosphatidylinositol-4,5-biphosphate 3-kinase (PIK3CA) when grown as tumor spheroids. Finally, we are able to further investigate and confirm the spatial impact of these dependencies using immunohistochemistry.

Identifying novel drug targets that transition from pre-clinical testing to human trials is a scientific priority. To that end, here we describe a functional genomics approach for examining the impact of gene depletion on cancer cell line spheroids, which more appropriately model human cancers in vivo.

利用功能基因组筛选识别在肿瘤细胞球体培养潜在的新药物靶标

The identification of functional driver events in cancer is central to furthering our understanding of cancer biology and indispensable for the discovery ...

Synthesis and Characterization of an Aspirin-fumarate Prodrug that Inhibits NF&#954;B Activity and Breast Cancer Stem Cells

Inflammation is a cancer hallmark that underlies cancer incidence and promotion, and eventually progression to metastasis. Therefore, adding an anti-inflammatory drug to standard cancer regiments may improve patient outcome. One such drug, aspirin (acetylsalicylic acid, ASA), has been explored for cancer chemoprevention and anti-tumor activity. Besides inhibiting the cyclooxygenase 2-prostaglandin axis, ASA&#39;s anti-cancer activities have also been attributed to nuclear factor &#312;B (NF&#312;B) inhibition. Because prolonged ASA use may cause gastrointestinal toxicity, a prodrug strategy has been implemented successfully. In this prodrug design the carboxylic acid of ASA is masked and additional pharmacophores are incorporated.
This protocol describes how we synthesized an aspirin-fumarate prodrug, GTCpFE, and characterized its inhibition of the NF&#312;B pathway in breast cancer cells and attenuation of the cancer stem-like properties, an important NF&#312;B-dependent phenotype. GTCpFE effectively inhibits the NF&#312;B pathway in breast cancer cell lines whereas ASA lacks any inhibitory activity, indicating that adding fumarate to ASA structure significantly contributes to its activity. In addition, GTCpFE shows significant anti-cancer stem cell activity by blocking mammosphere formation and attenuating the cancer stem cell associated CD44+CD24- immunophenotype. These results establish a viable strategy to develop improved anti-inflammatory drugs for chemoprevention and cancer therapy.

This procedure will demonstrate how we synthesized and characterized the anti-NF&#954;B and anti-cancer stem cell activity of an aspirin-fumarate prodrug.

合成与阿司匹林富马酸酯前药的表征抑制NFκB活动和乳腺癌干细胞

Inflammation is a cancer hallmark that underlies cancer incidence and promotion, and eventually progression to metastasis. Therefore, adding an ...

Invasive Behavior of Human Breast Cancer Cells in Embryonic Zebrafish

In many cases, cancer patients do not die of a primary tumor, but rather because of metastasis. Although numerous rodent models are available for studying cancer metastasis in vivo, other efficient, reliable, low-cost models are needed to quickly access the potential effects of (epi)genetic changes or pharmacological compounds. As such, we illustrate and explain the feasibility of xenograft models using human breast cancer cells injected into zebrafish embryos to support this goal. Under the microscope, fluorescent proteins or chemically labeled human breast cancer cells are transplanted into transgenic zebrafish embryos, Tg (fli:EGFP), at the perivitelline space or duct of Cuvier (Doc) 48 h after fertilization. Shortly afterwards, the temporal-spatial process of cancer cell invasion, dissemination, and metastasis in the living fish body is visualized under a fluorescent microscope. The models using different injection sites, i.e., perivitelline space or Doc are complementary to one another, reflecting the early stage (intravasation step) and late stage (extravasation step) of the multistep metastatic cascade of events. Moreover, peritumoral and intratumoral angiogenesis can be observed with the injection into the perivitelline space. The entire experimental period is no more than 8 days. These two models combine cell labeling, micro-transplantation, and fluorescence imaging techniques, enabling the rapid evaluation of cancer metastasis in response to genetic and pharmacological manipulations.

Here, we describe xenograft zebrafish models using two different injection sites, i.e., perivitelline space and duct of Cuvier, to investigate the invasive behavior and to assess the intravasation and extravasation potential of human breast cancer cells, respectively.

在斑马鱼胚胎人乳腺癌细胞的侵袭行为

In many cases, cancer patients do not die of a primary tumor, but rather because of metastasis. Although numerous rodent models are available for studying ...

Mesenchymal Stem Cell Isolation from Pulp Tissue and Co-Culture with Cancer Cells to Study Their Interactions

Cancer as a multistep process and complicated disease is not only regulated by individual cell proliferation and growth but also controlled by tumor environment and cell-cell interactions. Identification of cancer and stem cell interactions, including changes in extracellular environment, physical interactions, and secreted factors, might enable the discovery of new therapy options. We combine known co-culture techniques to create a model system for mesenchymal stem cells (MSCs) and cancer cell interactions. In the current study, dental pulp stem cells (DPSCs) and PC-3 prostate cancer cell interactions were examined by direct and indirect co-culture techniques. Condition medium (CM) obtained from DPSCs and 0.4 &#181;m pore sized trans-well membranes were used to study paracrine activity. Co-culture of different cell types together was performed to study direct cell-cell interaction. The results revealed that CM increased cell proliferation and decreased apoptosis in prostate cancer cell cultures. Both CM and trans-well system increased cell migration capacity of PC-3 cells. Cells stained with different membrane dyes were seeded into the same culture vessels, and DPSCs participated in a self-organized structure with PC-3 cells under this direct co-culture condition. Overall, the results indicated that co-culture techniques could be useful for cancer and MSC interactions as a model system.

We provide protocols for evaluation of mesenchymal stem cells isolated from dental pulp and prostate cancer cell interactions based on direct and indirect co-culture methods. Condition medium and trans-well membranes are suitable to analyze indirect paracrine activity. Seeding differentially stained cells together is an appropriate model for direct cell-cell interaction.

骨髓间充质干细胞在浆组织中的分离及与癌细胞联合培养研究其相互作用

Cancer as a multistep process and complicated disease is not only regulated by individual cell proliferation and growth but also controlled by tumor ...

Obtaining Cancer Stem Cell Spheres from Gynecological and Breast Cancer Tumors

Cancer stem cells (CSC) are a small population with self-renewal and plasticity which are responsible for tumorigenesis, resistance to treatment and recurrent disease. This population can be identified by surface markers, enzymatic activity and a functional profile. These approaches per se are limited, due to phenotypic heterogeneity and CSC plasticity. Here, we update the sphere-forming protocol to obtain CSC spheres from breast and gynecological cancers, assessing functional properties, CSC markers and protein expression. The spheres are obtained with single-cell seeding at low density in suspension culture, using a semi-solid methylcellulose medium to avoid migration and aggregates. This profitable protocol can be used in cancer cell lines but also in primary tumors. The tridimensional non-adherent suspension culture thought to mimic the tumor microenvironment, particularly the CSC-niche, is supplemented with epidermal growth factor and basic fibroblast growth factor to ensure CSC signaling. Aiming for robust identification of CSC, we propose a complementary approach, combining functional and phenotypic evaluation. Sphere-forming capacity, self-renewal and sphere projection area establish CSC functional properties. Additionally, characterization comprises flow cytometry evaluation of the markers, represented by CD44+/CD24- and CD133, and Western blot, considering ALDH. The presented protocol was also optimized for primary tumor samples, following a sample digestion procedure, useful for translational research.

The aim of this methodology is to identify cancer stem cells (CSC) in cancer cell lines and primary human tumor samples with the sphere-forming protocol, in a robust manner, using functional assays and phenotypic characterization with flow cytometry and Western blot.

从妇科和乳腺癌肿瘤获得癌症干细胞球

Cancer stem cells (CSC) are a small population with self-renewal and plasticity which are responsible for tumorigenesis, resistance to treatment and ...

Isolation of Stem-like Cells from 3-Dimensional Spheroid Cultures

Despite advances in adult stem cell research, identification and isolation of stem cells from tissue specimens remains a major challenge. While resident stem cells are relatively quiescent with niche restraints in adult tissues, they enter the cell cycle in anchor-free three-dimensional (3D) culture and undergo both symmetric and asymmetric cell division, giving rise to both stem and progenitor cells. The latter proliferate rapidly and are the major cell population at various stages of lineage commitment, forming heterogeneous spheroids. Using primary normal human prostate epithelial cells (HPrEC), a spheroid-based, label-retention assay was developed that permits the identification and functional isolation of the spheroid-initiating stem cells at a single cell resolution.
HPrEC or cell lines are two-dimensionally (2D) cultured with BrdU for 10 days to permit its incorporation into the DNA of all dividing cells, including self-renewing stem cells. Wash out commences upon transfer to the 3D culture for 5 days, during which stem cells self-renew through asymmetric division and initiate spheroid formation. While relatively quiescent daughter stem cells retain BrdU-labeled parental DNA, the daughter progenitors rapidly proliferate, losing the BrdU label. BrdU can be substituted with CFSE or Far Red pro-dyes, which permit live stem cell isolation by FACS. Stem cell characteristics are confirmed by in vitro spheroid formation, in vivo tissue regeneration assays, and by documenting their symmetric/asymmetric cell divisions. The isolated label-retaining stem cells can be rigorously interrogated by downstream molecular and biologic studies, including RNA-seq, ChIP-seq, single cell capture, metabolic activity, proteome profiling, immunocytochemistry, organoid formation, and in vivo tissue regeneration. Importantly, this marker-free functional stem cell isolation approach identifies stem-like cells from fresh cancer specimens and cancer cell lines from multiple organs, suggesting wide applicability. It can be used to identify cancer stem-like cell biomarkers, screen pharmaceuticals targeting cancer stem-like cells, and discover novel therapeutic targets in cancers.

Using human primary prostate epithelial cells, we report a novel biomarker-free method of functional characterization of stem-like cells by a spheroid-based label-retention assay. A step-by-step protocol is described for BrdU, CFSE, or Far Red 2D cell labeling; three-dimensional spheroid formation; label-retaining stem-like cell identification by immunocytochemistry; and isolation by FACS.

从3维球体培养中分离出类似干细胞的细胞

Despite advances in adult stem cell research, identification and isolation of stem cells from tissue specimens remains a major challenge. While resident ...

Functional Assessment of BRCA1 variants using CRISPR-Mediated Base Editors

Recent studies have investigated the risks associated with BRCA1 gene mutations using various functional assessment methods such as fluorescent reporter assays, embryonic stem cell viability assays, and therapeutic drug-based sensitivity assays. Although they have clarified a lot of BRCA1 variants, these assays involving the use of exogenously expressed BRCA1 variants are associated with overexpression issues and cannot be applied to post-transcriptional regulation. To resolve these limitations, we previously reported a method for functional analysis of BRCA1 variants via CRISPR-mediated cytosine base editor that induce targeted nucleotide substitution in living cells. Using this method, we identified variants whose functions remain ambiguous, including c.-97C&#62;T, c.154C&#62;T, c.3847C&#62;T, c.5056C&#62;T, and c.4986+5G&#62;A, and confirmed that CRISPR-mediated base editors are useful tools for reclassifying the variants of uncertain significance in BRCA1. Here, we describe a protocol for functional analysis of BRCA1 variants using CRISPR-based cytosine base editor. This protocol provides guidelines for the selection of target sites, functional analysis and evaluation of BRCA1 variants.

Functional Assessment of BRCA1 variants using CRISPR-Mediated Base Editors

People with BRCA1 mutations have a higher risk of developing cancer, which warrants accurate evaluation of the function of BRCA1 variants. Herein, we described a protocol for functional assessment of BRCA1 variants using CRISPR-mediated cytosine base editors that enable targeted C:G to T:A conversion in living cells.

使用 CRISPR 介质基础编辑器对 BRCA1 变体进行功能评估

Recent studies have investigated the risks associated with BRCA1 gene mutations using various functional assessment methods such as fluorescent reporter ...

Modeling Breast Cancer in Human Breast Tissue using a Microphysiological System

Breast cancer (BC) remains a leading cause of death for women. Despite more than $700 million invested in BC research annually, 97% of candidate BC drugs fail clinical trials. Therefore, new models are needed to improve our understanding of the disease. The NIH Microphysiological Systems (MPS) program was developed to improve the clinical translation of basic science discoveries and promising new therapeutic strategies. Here we present a method for generating MPS for breast cancers (BC-MPS). This model adapts a previously described approach of culturing primary human white adipose tissue (WAT) by sandwiching WAT between adipose-derived stem cell sheets (ASC)s. Novel aspects of our BC-MPS include seeding BC cells into non-diseased human breast tissue (HBT) containing native extracellular matrix, mature adipocytes, resident fibroblasts, and immune cells; and sandwiching the BC-HBT admixture between HBT-derived ASC sheets. The resulting BC-MPS is stable in culture ex vivo for at least 14 days. This model system contains multiple elements of the microenvironment that influence BC including adipocytes, stromal cells, immune cells, and the extracellular matrix. Thus BC-MPS can be used to study the interactions between BC and its microenvironment. 
We demonstrate the advantages of our BC-MPS by studying two BC behaviors known to influence cancer progression and metastasis: 1) BC motility and 2) BC-HBT metabolic crosstalk. While BC motility has previously been demonstrated using intravital imaging, BC-MPS allows for high-resolution time-lapse imaging using fluorescence microscopy over several days. Furthermore, while metabolic crosstalk was previously demonstrated using BC cells and murine pre-adipocytes differentiated into immature adipocytes, our BC-MPS model is the first system to demonstrate this crosstalk between primary human mammary adipocytes and BC cells in vitro.

This protocol describes the construction of an in vitro microphysiological system for studying breast cancer using primary human breast tissue with off the shelf materials.

使用微生理系统模拟人体乳房组织中的乳腺癌

Breast cancer (BC) remains a leading cause of death for women. Despite more than $700 million invested in BC research annually, 97% of candidate BC drugs ...

A Rapid Screening Workflow to Identify Potential Combination Therapy for GBM using Patient-Derived Glioma Stem Cells

The glioma stem cells (GSCs) are a small fraction of cancer cells which play essential roles in tumor initiation, angiogenesis, and drug resistance in glioblastoma (GBM), the most prevalent and devastating primary brain tumor. The presence of GSCs makes the GBM very refractory to most of individual targeted agents, so high-throughput screening methods are required to identify potential effective combination therapeutics. The protocol describes a simple workflow to enable rapid screening for potential combination therapy with synergistic interaction. The general steps of this workflow consist of establishing luciferase-tagged GSCs, preparing matrigel coated plates, combination drug screening, analyzing, and validating the results.

快速筛选工作流程，利用患者衍生胶质瘤干细胞确定GBM的潜在组合疗法

The glioma stem cells (GSCs) are a small fraction of cancer cells which play essential roles in tumor initiation, angiogenesis, and drug resistance in ...