Bu çalışmada grant tarafından desteklenen yok. CA-81301 Ulusal Kanser Enstitüsü'nden. Biz Bob Carlson Editör Yardım almak için Dr Peter Villalta ve Xun Ming için analitik Biyokimya paylaşılan kaynak Masonik Kanser Merkezi kütle spektrometresi yardım ve Dr Adam T. Zarth ve Dr Anna K. Michel onların değerli tartışmalar için teşekkür ederim ve giriş. Analitik Biyokimya paylaşılan kaynak kısmen Ulusal Kanser Enstitüsü Kanser Merkezi destek hibe CA-77598 tarafından desteklenmektedir

1. malzeme ve genel yordamları <ol><li>Synthesize NNN daha önce açıklandığı gibi 15. Norcotinine, P450 2A6 Baculosomes, NADPH rejenerasyon sistemi, 0.5 x reaksiyon tampon ve diğer kimyasal maddeler elde etmek veya reaktif sınıfta ticari kaynaklardan gelen solventler.</li>
	<li>Kayıt NMR spectra bir 500 MHz Spektrometre üzerinde. Rapor kimyasal vardiya başına parçaları olarak milyon (ppm). İç başvuru (7,26 ppm CDCl 3) için 1 H-NMR ve 13 C-NMR (77.2 ppm CDCl 3) kalan solvent doruklarına kullanın. 
	Not: Tepe bölme kullanılan aşağıdaki kısaltmalar: s singlet, d = eş, dd = eş birini, dt = üçüz, dq gelir = dörtlüsü, ddd gelir = kütleye kütleye birini ve m = multiplet =.</li>
	<li>Bir LTQ Orbitrap Velos ve rapor verilerini m/z olarak seçilen bileşikler için yüksek çözünürlüklü kütle spektrometresi (HRMS) gerçekleştirmek.</li>
	<li>Kullanım polygram silika jel TLC tabak (40 mm x 80 mm, 0.2 mm kalınlığında) ince katmanlı Kromatografi (TLC) 254 nm floresan göstergesi ön kaplamalı. TLC plakaları UV lamba ışınlama tarafından görselleştirmek.</li>
	<li>Flash Kromatografi bir 60 Å, 70-150 mesh silika jel 1,5 cm x 15 cm cam sütun kullanarak gerçekleştirmek.</li>
</ol> 2. Nitrosamide olumlu denetim hazırlanması (N &#8242;-nitrosonorcotinine, NNC) <ol><li>kuru, bir fırın gecede (16 h, ~ 140 ° C), 25 mL yuvarlak alt şişesi manyetik heyecan çubuğunu içeren. Sabah, serin altında N 2 akışı tutmak için bir petrol bubbler kullanırken bir akış N 2 şişeye oranı saniyede bir kabarcık. 
	Not: soğutma sonra şişeye N 2 altında tutmak için hiçbir önlem gereklidir.</li>
	<li>Bir duman başlık, soğutmalı şişeye norcotinine (31,8 mg, 0.196 mmol), asetik anhidrit (5 mL) ve Asetik asit (1 mL) ekleyin. 0 ° C su buz banyosu ile soğutma sırasında sürekli olarak bu karışımı ilave edin. 
	Uyarı: Asetik anhidrit ve Asetik asit aşındırıcı.</li>
	<li>NaNO eklemek 2 (33.3 mg, 0.483 mmol) bir bölümünü ve sürekli olarak 2.5 h. TLC tarafından tepki ilerlemeyi izleme için karışımı ilave edin (%100 EtOAc, R f = 0,19, bkz: adım 1.4). 
	Not: Bu zaman içinde karışım ara sıra köpüren ile giderek sarı olacak.</li>
	<li>Buz gibi H 2 O içine karışımı (18 mL) dökerek tepki gidermek. Hemen 18 mL CH 2 Cl 2 100 mL HCI'yi huni ile sulu çözüm ayıklayın. CH 2 Cl 2 (9 her mL) ile en az 2 ek kez sulu katman ayıklamak.</li>
	<li>Üzerinde ~ 100 mg MgSO 4 2 dk. filtre için havuza alınan Organik Kuru ve çözüm tarafından döner buharlaşma-ham, sarı yağ verimi için konsantre. Su banyosu ile 30 ° C arasında kalan Asetik asit kaldırmak için buharlaşma sırasında ısı. 
	Not: bileşik CH 2 Cl 2 ve 2-8 ° c karanlıkta saklanan çözüm içinde çözünmüş Eğer protokol burada duraklatılmış</li>
	<li>Arındırmak ham bileşik sütun Kromatografi tarafından (bkz. Adım 1.5) durağan faz ve % 100 silika jel kullanarak EtOAc olarak eluent 16. 
	Uyarı: NNC ve ilgili nitrosamides ele alınabilir özenle insan kanserojen olarak kabul edilir gibi.</li>
	<li>CDCl 3 ' te saf bileşik dağıtılması ve NMR kullanın (bkz. Adım 1.2) yapısı onaylamak ve bu çözüm 17 Derişim belirlemek için. 2-8 ° C'de gerekinceye kadar karanlıkta bu çözüm mağaza. 
	Not: Bu çözüm olumlu denetim vitro tahlil (Adım 3.5) olarak kullanılır. NMR spectra ve kimyasal vardiya destek bilgileri mevcuttur.</li>
	<li>Saf NNC çözümle, doğru onaylamak üst kitle ve ürün iyon kitleler tarafından yüksek çözünürlüklü bir Kütle Spektrometre (HRMS) üzerinde doğrudan infüzyon 1.3 ve 4.3 adımlarda açıklanan parametreleri altında belirlemek. 
	Not: Ürün kitleler vitro metabolizma tahlil (Adım 4.3) bu bileşik algılamak için kullanılan.</li>
</ol> 3. Bir örnek nitrosamine P450 vitro kuluçka <ol><li>-80 ° C dondurucudan P450 2A6 Baculosomes, canlı-NADPH-rejenerasyon sistemi ve 10 mM NADP + hisse senedi çözüm kaldırmak ve onları buza çözülme izin. Bir kez çözdürülen, Baculosomes ve NADPH rejenerasyon sistem 1 seyreltik: 10 ve 1:50, sırasıyla, bir tek 1 mL tüp ile 0.5 X reaksiyon arabellek içine. Benzer şekilde, reaksiyon arabellek X + hisse senedi çözüm 0,5 97 μL NADP 3 μL ekleyin. 
	Not: NADP + ışığa duyarlı olduğunu. Bu çözüm kapsayıcısının alüminyum folyo sarma tarafından korunan tutmak. Enzim çözümleri için donma-çözülme çevrimleri duyarlıdır; Bu fazla 2 geçer sınırlayın. Aliquots gelecekteki deneyler için gerektiği gibi hazırlayın.</li>
	<li>(5 pmol P450 içeren) enzim çözüm 1 ml 50 μL tüp tepki arabellek ile yapılan 4 mikron NNN çözüm içeren 40 μL her kuluçka için ekleyin. Bu yeni karışım bir su banyosu kullanarak 37 ° C'de 2 min için önceden kuluçkaya ve 10 μL seyreltilmiş NADP + çözüm ekleyin. 1-30 dk 37 için tam sistem kuluçkaya ° C. 
	Not: 5 dk aralıklarla kullanarak kuluçka kez için (örneğin 5, 10, 15 dk, vb) bir yeterli nitrosamide oluşumu saat ders verecek.</li>
	<li>İlk ekleyerek 10 μl 3.0 N ZnSO 4 ve 3.0 N Ba(OH) sonra 10 μL tarafından istenen kuluçka süre sonra susuzluğumu 2. Girdap bu çözüm ve beyaz çökelti oluşturacak. 8000 x g çökelti cips için 4 dakika için de örnek santrifüj kapasitesi. 
	Not: kurulan nitrosamides sulu çözümler istikrardır sınırlı olarak prosedür bu adımda duraklatmak gerekir değil. Uzun duraklar içinde yanlış negatif neden olabilir.</li>
	<li>Hemen süpernatant pipette ve 2 μL sıvı Kromatografi olumlu nanoelectrospray-iyonizasyon yüksek çözünürlüklü tandem kütle spektrometresi tarafından analiz (LC-NSI +-HRMS/MS, adımlar 4.1-4.3).</li>
	<li>Altında N akışı 2 1 mL tüp içine sentezlenmiş NNC çözeltinin 100 fmol içeren bir aliquot pozitif kontrol incubations için buharlaşır. Bu şişe için tam enzim sistemi 3.2 adımından ekleyin ve adımları 3.3-3.4 açıklandığı gibi devam edin.</li>
	<li>Negatif kontrol incubations için deneme açıklanan (adımları 3.2-3,4) Değiştir 50 μL enzim reaksiyon arabellek X 0.5 Çözümle dışında gerçekleştirin.</li>
</ol> 4. Örnek parametreleri LC-NSI + tarafından nitrosamide algılama için-HRMS/MS <ol><li>için LC bileşeni, bir ticari, el-Paketli 18 C18 kullanarak UPLC sisteme adım 4.2 aşağıdaki Multi-step degrade uygulayın (5 mikron), 100 mm x 75 mikron, 15 μm kalınlığında orifis kapiller sütun.</li>
	<li>Kullanarak 5 mM NH 4 OAc çözelti A ve çözücü B olarak MeCN olarak %5 B 1 μL/dk çalıştırarak örnek sütuna yükleme 0 - 5 min ve debisi 0,3 μL/dk sonra yavaşlama. Ardından, bir degrade üzerinde 4 dk ardından rampa %55 B 10 dk ve o zaman yeniden denge için % 5, % 20'si B 5 çalıştırın B.</li>
	<li>Gerçekleştirmek LC-NSI +-HRMS/MS LTQ Orbitrap üzerinde. Tam tarama ve MS 2 parçalanma monitör NNC için. 60.000 çözünürlükte tam tarama gerçekleştirmek ve bir kitle toleransı 5 ppm doğru üst kitle (192.07670) ayıklayın. Çarpışma kaynaklı ayrılma 25 ev, 15.000, çözünürlük tarafından (CID) bir çarpışma enerjisi ile üst iyonları (2.0 amu) ve parçası yalıtmak ve 30 Bayan zaman inceden inceye gözden geçirmek için kullanım MS 2 parçalanma NNC (m/z doğru kitlelerin ürün iyonları için ayıklamak 192 m/z 134.04739 ve 162.07874) adlı bir kitle hoşgörü 5 PPM.</li>
</ol>

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Yazarlar ifşa gerek yok.

Nitrozaminler metabolizma elucidating onların carcinogenicity anlamak için önemli bir bileşenidir. Daha fazla yer sitokrom P450s ve diğer Metabolik enzimler Polimorfik olduğundan, bu bilginin uygulaması potansiyel olarak yüksek riskli bireyler1,4teşhis edebilir. Yeni veri α-hydroxynitrosamines, nitrozaminler DNA bağlamasında dahil tahmin ediliyor büyük metabolitleri daha fazla o oksidasyonunu gösterir, nitrosamides için mümkündür; Ancak, bu sa?...

N-nitrozamin çoğu diyet, tütün ürünleri ve genel çevre; bulunan kanserojen büyük bir sınıf Onlar da endogenously insan vücudu1' oluşturulması mümkündür. 300'den fazla N -nitrozo bileşikler test ettik ve &#62; % 90 gibi kanserojen olarak değerlendirilmiştir hayvan modelleri2,3. Onların carcinogenicity sergilemek, bu bileşiklerin tarafından sitokrom P450s1,2,3etkinleştirilmesi gerekir. Araştırma gösterir o sitokrom P450s kolayca okside nitrozaminler için α-hydroxynitrosamines (Resim 1), yarı-ömrü ~ 5 olan büyük ölçüde reaktif bileşikleri olan s kendiliğinden alkyldiazohydroxides için çürümeye başladı önce. İkinci DNA H2O ve N2kaybettikten sonra alkylate. Elde edilen DNA adducts, eğer unrepaired, kritik onko - veya Tümör baskılayıcı genler, Eğer kanser geliştirme1' e kurşun mutasyonlar neden olabilir. Bu nedenle, çok çaba metabolik yollar tam bir anlayış kazanmak için harcanan, DNA adducts ve sitokrom P450 oksidasyon kanserojen nitrozaminler ve aşağı akım metabolitleri. Bu bilgi bireysel kanser risk değerlendirme4' te potansiyel uygulama var.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56312/56312fig1.jpg"> 
Resim 1: Genel ve önerilen metabolizması nitrozaminler. Nitrozaminler (1) P450s tarafından α-hydroxynitrosamines (2) bu kendiliğinden alkyldiazohydroxides (3) ayrıştırmak için okside. Bu bileşikler DNA için DNA adducts forma bağlayabilirsiniz. Bu onaylanmadığına karar o 2 daha fazla nitrosamides 4' e P450s tarafından okside. Bunlar doğrudan DNA için roman DNA adducts veya 3 bilinen DNA adducts forma hidrolize formu bağlayabilirsiniz. R1 ve R2 herhangi bir alkil grubu temsil eder. <a href="//ecsource.jove.com/files/ftp_upload/56312/56312fig1large.jpg" target="_blank">Bu rakam daha büyük bir versiyonunu görüntülemek için buraya tıklayınız.</a>
α-hydroxynitrosamine hipotez sağlam geniş kapsamlı veriler tarafından desteklenir, ancak bazı tutarsızlıklar vardır; α-hydroxynitrosamines5,6kısa yarılanma büyük olanıdır. Bu bileşikler endoplazmik retikulum membran üretilir ve daha sonra nükleer DNA alkylate bilinir. Ömürleri birkaç saniyelik göz önüne alındığında, bu nasıl bu ara ürün gerekli seyahat gerçi sitozol hayatta şaşırtıcı. α-hydroxynitrosamines bir kısmını processively okside olduğunu nitrosamides7,8' e, hangi karşılaştırma9' oldukça istikrarlı bir hipotezdir. Bu muhtemelen α-hydroxynitrosamines sitokrom P450 etkin sitedeki tutma ile oluşacak. Bu tür bir oksidasyon için emsal nikotin10, alkoller11ve basit alkylnitrosamines12,13ile görülmüştür. Ayrıca, doğrudan etkili kanserojen2,3nitrosamides bulunmaktadır. Onların reaktivite9tarihinde dayanarak, bu bileşiklerin inanılıyor DNA üretmek için kullanılanlarla aynı α-hydroxynitrosamines ile birlikte yeni kaynaklanan adducts, keşfedilmemiş DNA (şekil 1) adducts. Böylece, bu hipotez sadece sitozol yoluyla ulaşım açıklar, ama Ayrıca DNA oluşumu zarar ürünleri.
Bu yazıda, vitro sitokrom P450-aracılı dönüşüm nitrozaminler nitrosamides değerlendirmek için genel bir protokol açıklanmıştır. N′- nitrosonorcotinine (NNC) sitokrom P450 2A6 tarafından N′- nitrosonornicotine (NNN) daha önce raporlanmış dönüşüm bir örnek14olarak sergiledi. Bu protokolün uygulamaya substrat enzim sistemleri geniş bir nitrosamides genel nitrosamine metabolizması önemini belirlemenize yardımcı olur.

<table>
	<tbody>
		<tr>
			<td>Norcotinine</td>
			<td>AKoS GmbH (Steinen, Germany)</td>
			<td>CAS 17708-87-1, AKoS AK0S006278969</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetic acid</td>
			<td>Sigma-Aldrich</td>
			<td>695092</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetic Anhydride</td>
			<td>Sigma-Aldrich</td>
			<td>242845</td>
			<td></td>
		</tr>
		<tr>
			<td>Ammonium Acetate</td>
			<td>Sigma-Aldrich</td>
			<td>431311</td>
			<td></td>
		</tr>
		<tr>
			<td>Barium Hydroxide</td>
			<td>Sigma-Aldrich</td>
			<td>433373</td>
			<td></td>
		</tr>
		<tr>
			<td>D-Chloroform</td>
			<td>Sigma-Aldrich</td>
			<td>151823</td>
			<td></td>
		</tr>
		<tr>
			<td>HPLC Acetonitrile</td>
			<td>Sigma-Aldrich</td>
			<td>34998</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnesium Sulfate</td>
			<td>Sigma-Aldrich</td>
			<td>M7506</td>
			<td></td>
		</tr>
		<tr>
			<td>Methylene Chloride</td>
			<td>Sigma-Aldrich</td>
			<td>34856</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Nitrite</td>
			<td>Sigma-Aldrich</td>
			<td>237213</td>
			<td></td>
		</tr>
		<tr>
			<td>ViVid CYP2A6 Blue Screening Kit</td>
			<td>Life Technologies</td>
			<td>PV6140</td>
			<td></td>
		</tr>
		<tr>
			<td>Zinc Sulfate</td>
			<td>Sigma-Aldrich</td>
			<td>221376</td>
			<td></td>
		</tr>
		<tr>
			<td>0.5 mL tubes</td>
			<td>Fisher</td>
			<td>AB0533</td>
			<td></td>
		</tr>
		<tr>
			<td>100 mL round bottom flask</td>
			<td>Sigma-Aldrich</td>
			<td>Z510424</td>
			<td></td>
		</tr>
		<tr>
			<td>125 mL Erlenmeyer flask</td>
			<td>Sigma-Aldrich</td>
			<td>CLS4980125</td>
			<td></td>
		</tr>
		<tr>
			<td>125 mL Separatory Funnel</td>
			<td>Sigma-Aldrich</td>
			<td>Z261017</td>
			<td></td>
		</tr>
		<tr>
			<td>25 mL round bottom flask</td>
			<td>Sigma-Aldrich</td>
			<td>Z278262</td>
			<td></td>
		</tr>
		<tr>
			<td>500 MHz NMR Spectrometer</td>
			<td>Bruker</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Allegra X-22R Centrifuge</td>
			<td>Beckman-Coulter</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>LC vials</td>
			<td>ChromTech</td>
			<td>CTC&#8211;0957&#8211;BOND</td>
			<td></td>
		</tr>
		<tr>
			<td>LTQ Orbitrap Velos</td>
			<td>Thermo Scientific</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Magnetic Stir bar</td>
			<td>Sigma-Aldrich</td>
			<td>Z127035</td>
			<td></td>
		</tr>
		<tr>
			<td>NMR tube</td>
			<td>Sigma-Aldrich</td>
			<td>Z274682</td>
			<td></td>
		</tr>
		<tr>
			<td>P1000, P200, and P10 pipettes</td>
			<td>Eppendorf</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Rotary evaporator</td>
			<td>Sigma-Aldrich</td>
			<td>Z691410</td>
			<td></td>
		</tr>
		<tr>
			<td>RSLCnano UPLC system</td>
			<td>Thermo Scientific</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Shaking Water Bath</td>
			<td>Fisher</td>
			<td>FSSWB15</td>
			<td></td>
		</tr>
		<tr>
			<td>Stir plate</td>
			<td>Sigma-Aldrich</td>
			<td>CLS6795420</td>
			<td></td>
		</tr>
		<tr>
			<td>PicoFrit Column</td>
			<td>New Objective</td>
			<td>PF3607515N5</td>
			<td></td>
		</tr>
		<tr>
			<td>Luna C18, 5 um</td>
			<td>Phenomenex</td>
			<td>535913-1</td>
			<td></td>
		</tr>
	</tbody>
</table>

a general method for detecting nitrosamide formation in the in vitro metabolism of nitrosamines by cytochrome p450s

N-nitrozamin aktivite sergilemek sitokrom P450 oksidasyon gerektiren çevre kanserojen iyi kurulmuş bir grup vardır. Metabolik aktivasyon kabul edilen mekanizması oluşumu kendiliğinden DNA etmen acentelere ayrıştırmak α-hydroxynitrosamines içerir. DNA hasarı ve elde edilen mutasyonlar birikimi sonuçta kansere yol açabilir. Yeni kanıtlar α-hydroxynitrosamines daha fazla nitrosamides için processively sitokrom P450s tarafından okside olduğunu gösterir. Nitrosamides genellikle daha α-hydroxynitrosamines daha kararlı ve ayrıca DNA alkylate çünkü nitrosamides karsinojenezis içinde bir rol oynayabilir. Bu raporda, vitro sitokrom P450 katalize metabolizma üzerinden nitrosamide üretimini nitrozaminler değerlendirmek için genel bir iletişim kuralı açıklar. Bu iletişim kuralı ilgili nitrosamides ve algılama için sıvı Kromatografi-nanospray iyonlaşma-yüksek çözünürlüklü tandem kütle spektrometresi kullanılarak bir vitro sitokrom P450 metabolizma tahlil sentezi için genel bir yaklaşım kullanır. Bu yöntem N′- nitrosonorcotinine N′- nitrosonornicotine örnek çalışma küçük bir metaboliti olarak algılandı. Yüksek hassasiyet ve seçmeli olarak nedeniyle doğru kitle algılama yöntemi vardır. Bu yöntemin uygulama çok çeşitli nitrosamine sitokrom P450 sistemleri için bu dönüşüm genelliği belirlemenize yardımcı olur. Sitokrom P450s Polimorfik ve etkinliğini değişir çünkü nitrosamide oluşumu daha iyi bir anlayış içinde bireysel kanser risk değerlendirmesi yardımı olabilir.

Beyaz ve arkçalışmasına dayanmaktadır. 19, norcotinine nitrosated NNC için temiz bir şekilde ve yüksek verim (% 80-92) vitro deney için bir standart üretmek oldu. Başarılı bir tepki için yapısal kanıt spektroskopik 1H-NMR, 13C-NMR, rahat ve HSQC (destek bilgileri) ile birlikte üst kitle [M + H] teyit HRMS gibi analizler üzerinden elde edilen+ 5 ppm içinde Teorik değeri (Şek...

Watch this Scientific Journal Video about A General Method for Detecting Nitrosamide Formation in the In Vitro Metabolism of Nitrosamines by Cytochrome P450s at JoVE.com

A General Method for Detecting Nitrosamide Formation in the In Vitro Metabolism of Nitrosamines by Cytochrome P450s

Α-prokollajen sitokrom P450s tarafından kanserojen nitrozaminler ve mutasyonlar neden DNA-zarar intermediates üretir kabul edilen metabolik yoludur. Ancak, yeni verileri daha fazla nitrosamides oksidasyon oluşabilir gösterir. Biz genel bir tarif yöntemi nitrosamides tespit için üretilen vitro sitokrom P450 katalize metabolizması nitrozaminler.

Nitrosamide oluşumu nitrozaminler sitokrom P450s tarafından in Vitro metabolizma saptamak için bir genel yöntem

N-nitrosamines are a well-established group of environmental carcinogens, which require cytochrome P450 oxidation to exhibit activity. The accepted ...

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Cancer Research

A General Method for Detecting Nitrosamide Formation in the In Vitro Metabolism of Nitrosamines by Cytochrome P450s

9.9K Görüntüleme.  University of Minnesota. Α-prokollajen sitokrom P450s tarafından kanserojen nitrozaminler ve mutasyonlar neden DNA-zarar intermediates üretir kabul edilen metabolik yoludur. Ancak, yeni verileri daha fazla nitrosamides oksidasyon oluşabilir gösterir. Biz genel bir tarif yöntemi nitrosamides tespit için üretilen vitro sitokrom P450 katalize metabolizması nitrozaminler.

Video: A General Method for Detecting Nitrosamide Formation in the In Vitro Metabolism of Nitrosamines by Cytochrome P450s

The Drosophila Imaginal Disc Tumor Model: Visualization and Quantification of Gene Expression and Tumor Invasiveness Using Genetic Mosaics

Drosophila melanogaster has emerged as a powerful experimental system for functional and mechanistic studies of tumor development and progression in the context of a whole organism. Sophisticated techniques to generate genetic mosaics facilitate induction of visually marked, genetically defined clones surrounded by normal tissue. The clones can be analyzed through diverse molecular, cellular and omics approaches. This study describes how to generate fluorescently labeled clonal tumors of varying malignancy in the eye/antennal imaginal discs (EAD) of Drosophila larvae using the Mosaic Analysis with a Repressible Cell Marker (MARCM) technique. It describes procedures how to recover the mosaic EAD and brain from the larvae and how to process them for simultaneous imaging of fluorescent transgenic reporters and antibody staining. To facilitate molecular characterization of the mosaic tissue, we describe a protocol for isolation of total RNA from the EAD. The dissection procedure is suitable to recover EAD and brains from any larval stage. The fixation and staining protocol for imaginal discs works with a number of transgenic reporters and antibodies that recognize Drosophila proteins. The protocol for RNA isolation can be applied to various larval organs, whole larvae, and adult flies. Total RNA can be used for profiling of gene expression changes using candidate or genome-wide approaches. Finally, we detail a method for quantifying invasiveness of the clonal tumors. Although this method has limited use, its underlying concept is broadly applicable to other quantitative studies where cognitive bias must be avoided.

The Drosophila Imaginal Disc Tumor Model: Visualization and Quantification of Gene Expression and Tumor Invasiveness Using Genetic Mosaics

This protocol demonstrates how to generate fluorescently marked, genetically defined clonal tumors in the Drosophila eye/antennal imaginal discs (EAD). It describes how to dissect the EAD and brain from the third instar larvae and how to process them to visualize and quantify gene expression changes and tumor invasiveness.

<em&gt; Drosophila</em&gt; Hayali Disk Tümör Modeli: Genetik Mozaikler kullanma Gen İfade ve Tümör invazivliğinin Görselleştirme ve

Drosophila melanogaster has emerged as a powerful experimental system for functional and mechanistic studies of tumor development and progression in the ...

Kanser Araştırmaları

Evaporation-reducing Culture Condition Increases the Reproducibility of Multicellular Spheroid Formation in Microtiter Plates

Tumor models that closely imitate in vivo conditions are becoming increasingly popular in drug discovery and development for the screening of potential anti-cancer drugs. Multicellular tumor spheroids (MCTSes) effectively mimic the physiological conditions of solid tumors, making them excellent in vitro models for lead optimization and target validation. Out of the various techniques available for MCTS culture, the liquid-overlay method on agarose is one of the most inexpensive methods for MCTS generation. However, the reliable transfer of MCTS cultures using liquid-overlay for high-throughput screening may be compromised by a number of limitations, including the coating of microtiter plates (MPs) with agarose and the irreproducibility of uniform MCTS formation across wells. MPs are significantly prone to edge effects that result from excessive evaporation of medium from the exterior of the plate, preventing the use of the entire plate for drug tests. This manuscript provides detailed technical improvements to the liquid-overlay technique to increase the scalability and reproducibility of uniform MCTS formation. Additionally, details on a simple, semi-automatic, and universally applicable software tool for the evaluation of MCTS features after drug treatment is presented.

The uneven loss of medium from microtiter plates affects the reproducibility of uniform multicellular tumor spheroid formation. Improving culture conditions to reduce significant medium loss will improve the reproducibility of spheroid formation and the results of spheroid-based assays using the liquid-overlay technique.

Buharlaşma azaltıcı Kültür Durumu Mikrotiter Tabaklar Multisellüler Sfero Oluşumunun Tekrarlanabilirlik artırır

Tumor models that closely imitate in vivo conditions are becoming increasingly popular in drug discovery and development for the screening of potential ...

A Unified Methodological Framework for Vestibular Schwannoma Research

Vestibular schwannomas are the most common neoplasms of the cerebellopontine angle, making up 6-8% percent of all intracranial growths. Though these tumors cause sensorineural hearing loss in up to 95% of affected individuals, the molecular mechanisms underlying this hearing loss remain elusive. This article outlines the steps established in our laboratory to facilitate the collection and processing of various primary human tissue samples for downstream research applications integral to the study of vestibular schwannomas. Specifically, this work describes a unified methodological framework for the collection, processing, and culture of Schwann and schwannoma cells from surgical samples. This is integrated with parallel processing steps now considered essential for current research: the collection of tumor and nerve secretions, the preservation of RNA and the extraction of protein from collected tissues, the fixation of tissue for the preparation of sections, and the exposure of primary human cells to adeno-associated viruses for application to gene therapy. Additionally, this work highlights the translabyrinthine surgical approach to collect this tumor as a unique opportunity to obtain human sensory epithelium from the inner ear and perilymph. Tips to improve experimental quality are provided and common pitfalls highlighted.

The goal of this protocol is to outline the collection and processing of human surgical samples for multiple downstream applications in vestibular schwannoma and Schwann cell research.

Vestibüler Schwannoma Araştırması İçin Birleştirilmiş Metodolojik Çerçeve

Vestibular schwannomas are the most common neoplasms of the cerebellopontine angle, making up 6-8% percent of all intracranial growths. Though these ...

Moving Upwards: A Simple and Flexible In Vitro Three-dimensional Invasion Assay Protocol

Although 3D invasion assays have been developed, the challenge remains to study cells without affecting the integrity of their microenvironment. Traditional 3D assays such as the Boyden Chamber require that cells are displaced from the original culture location and moved to a new environment. Not only does this disrupt the cellular processes that are intrinsic to the microenvironment, but it often results in a loss of cells. These problems are especially challenging when dealing with cells that are either rare, or extremely sensitive to their microenvironment. Here, we describe the development of a 3D invasion assay that avoids both concerns. In this assay, cells are plated within a small well and an ECM matrix containing a chemoattractant is laid atop the cells. This requires no cell displacement, and allows the cells to invade upwards into the matrix. In this assay, cell invasion as well as cell morphology can be assessed within the collagen gel. Using this assay, we characterize the invasive capacity of rare and sensitive cells; the hybrid cells resulting from fusion between breast cancer cells MCF7 and mesenchymal/multipotent stem/stroma cells (MSCs).

Moving Upwards: A Simple and Flexible In Vitro Three-dimensional Invasion Assay Protocol

This protocol describes an inverted vertical invasion assay that could be used to quantify the migration and invasion capabilities of cells in a three-dimensional setting while preserving the cell microenvironment. This assay is suitable for rare and/or sensitive cells.

Yukarı doğru hareket: Bir basit ve esnek Vitro üç boyutlu işgali tahlil iletişim kuralı

Although 3D invasion assays have been developed, the challenge remains to study cells without affecting the integrity of their microenvironment. ...

Phosphopeptide Enrichment Coupled with Label-free Quantitative Mass Spectrometry to Investigate the Phosphoproteome in Prostate Cancer

Phosphoproteomics involves the large-scale study of phosphorylated proteins. Protein phosphorylation is a critical step in many signal transduction pathways and is tightly regulated by kinases and phosphatases. Therefore, characterizing the phosphoproteome may provide insights into identifying novel targets and biomarkers for oncologic therapy. Mass spectrometry provides a way to globally detect and quantify thousands of unique phosphorylation events. However, phosphopeptides are much less abundant than non-phosphopeptides, making biochemical analysis more challenging. To overcome this limitation, methods to enrich phosphopeptides prior to the mass spectrometry analysis are required. We describe a procedure to extract and digest proteins from tissue to yield peptides, followed by an enrichment for phosphotyrosine (pY) and phosphoserine/threonine (pST) peptides using an antibody-based and/or titanium dioxide (TiO2)-based enrichment method. After the sample preparation and mass spectrometry, we subsequently identify and quantify phosphopeptides using liquid chromatography-mass spectrometry and analysis software.

This protocol describes a procedure to extract and enrich phosphopeptides from prostate cancer cell lines or tissues for an analysis of the phosphoproteome via mass spectrometry-based proteomics.

Prostat kanserinde Phosphoproteome araştırmak için etiket içermeyen nicel kütle spektrometresi ile birleştiğinde Phosphopeptide zenginleştirme

Phosphoproteomics involves the large-scale study of phosphorylated proteins. Protein phosphorylation is a critical step in many signal transduction ...

Detection of Lung Tumor Progression in Mice by Ultrasound Imaging

With ~1.6 million victims per year, lung cancer contributes tremendously to the worldwide burden of cancer. Lung cancer is partly driven by genetic alterations in oncogenes such as the KRAS oncogene, which constitutes ~25% of lung cancer cases. The difficulty in therapeutically targeting KRAS-driven lung cancer partly stems from having poor models that can mimic the progression of the disease in the lab. We describe a method that permits the relative quantification of primary KRAS lung tumors in a Cre-inducible LSL-KRAS G12D mouse model via ultrasound imaging. This method relies on brightness (B)-mode acquisition of the lung parenchyma. Tumors that are initially formed in this model are visualized as B-lines and can be quantified by counting the number of B-lines present in the acquired images. These would represent the relative tumor number formed on the surface of the mouse lung. As the formed tumors develop with time, they are perceived as deep clefts within the lung parenchyma. Since the circumference of the formed tumor is well-defined, calculating the relative tumor volume is achieved by measuring the length and width of the tumor and applying them in the formula used for tumor caliper measurements. Ultrasound imaging is a non-invasive, fast and user-friendly technique that is often used for tumor quantifications in mice. Although artifacts may appear when obtaining ultrasound images, it has been shown that this imaging technique is more advantageous for tumor quantifications in mice compared to other imaging techniques such as computed tomography (CT) imaging and bioluminescence imaging (BLI). Researchers can investigate novel therapeutic targets using this technique by comparing lung tumor initiation and progression between different groups of mice.

This protocol describes the steps taken to induce KRAS lung tumors in mice as well as the quantification of formed tumors by ultrasound imaging. Small tumors are visualized in early timepoints as B-lines. At later timepoints, relative tumor volume measurements are achieved by the measurement tool in the ultrasound software.

Ultrason Görüntüleme ile Farelerde Akciğer Tümörü İlerlemesinin Saptanması

With ~1.6 million victims per year, lung cancer contributes tremendously to the worldwide burden of cancer. Lung cancer is partly driven by genetic ...

In Vitro Evaluation of Oncogenic Transformation in Human Mammary Epithelial Cells

Tumorigenesis is a multi-step process in which cells acquire capabilities&#160;that allow their growth, survival, and dissemination under hostile conditions. Different tests seek to identify and quantify these hallmarks of cancerous cells; however, they often focus on a single aspect of cellular transformation and, in fact, multiple tests are required for their proper characterization. The purpose of this work is to provide researchers with a set of tools to assess cellular transformation in vitro from a broad perspective, thereby making it possible to draw sound conclusions.
A sustained proliferative signaling activation is the major feature of tumoral tissues and can be easily monitored under in vitro conditions by calculating the number of population doublings achieved over time. Besides, the growth of cells in 3D cultures allows their interaction with surrounding cells, resembling what occurs in vivo. This enables the evaluation of cellular aggregation and, together with immunofluorescent labeling of distinctive cellular markers, to obtain information on another relevant feature of tumoral transformation: the loss of proper organization. Another remarkable characteristic of transformed cells is their capacity to grow without attachment to other cells and to the extracellular matrix, which can be evaluated with the anchorage assay.
Detailed experimental procedures to evaluate cell growth rate, to perform immunofluorescent labeling of cell lineage markers in 3D cultures, and to test anchorage-independent cell growth in soft agar are provided. These methodologies are optimized for Breast Primary Epithelial Cells (BPEC) due to its relevance in breast cancer; however, procedures can be applied to other cell types after some adjustments.

This protocol provides experimental in vitro tools to evaluate the transformation of human mammary cells. Detailed steps to follow-up cell proliferation rate, anchorage-independent growth capacity, and distribution of cell lineages in 3D cultures with basement membrane matrix are described.

İnsan Meme Epitel Hücrelerinde Onkojenik Dönüşümün İn Vitro Değerlendirilmesi

Tumorigenesis is a multi-step process in which cells acquire capabilities&#160;that allow their growth, survival, and dissemination under hostile ...

Monitoring Breast Cancer Growth and Metastatic Colony Formation in Mice using Bioluminescence

Breast cancer is a frequent heterogeneous malignancy and the second leading cause of mortality in women, mainly due to distant organ metastasis. Several animal models have been generated, including the widely used orthotopic mouse models, where cancer cells are injected into the mammary fat pad. However, these models cannot help monitor tumor growth kinetics and metastatic colonization. Cutting-edge tools to monitor cancer cells in real time in mice will significantly advance the understanding of tumor biology. 
Here, breast cancer cell lines stably expressing luciferase and green fluorescent protein (GFP) were established. Specifically, this technique contains two sequential steps initiated by measuring the luciferase activity in vitro and followed by the implantation of the cancer cells into mammary fat pads of nonobese diabetic-severe combined immunodeficiency (NOD-SCID) mice. After the injection, both the tumor growth and metastatic colonization are monitored in real time by the noninvasive bioluminescence imaging system. Then, the quantification of GFP-expressing metastases in the lungs will be examined by fluorescence microscopy to validate the observed bioluminescence results. This sophisticated system combining luciferase and fluorescence-based detection tools evaluates cancer metastasis in vivo, which has great potential for use in breast cancer therapeutics and disease management.

Here, we describe a noninvasive monitoring method involving luciferase and green fluorescent protein expression in various breast cancer cell lines. This protocol provides a technique to monitor tumor formation and metastatic colonization in real time in mice.

Biyolüminesans Kullanarak Farelerde Meme Kanseri Büyümesi ve Metastatik Koloni Oluşumunun İzlenmesi

Breast cancer is a frequent heterogeneous malignancy and the second leading cause of mortality in women, mainly due to distant organ metastasis. Several ...

Exploring the Arginine Methylome by Nuclear Magnetic Resonance Spectroscopy

Protein-bound arginine is commonly methylated in many proteins and regulates their function by altering the physicochemical properties, their interaction with other molecules, including other proteins or nucleic acids. This work presents an easily implementable protocol for quantifying arginine and its derivatives, including asymmetric and symmetric dimethylarginine (ADMA and SDMA, respectively) and monomethyl arginine (MMA). Following protein isolation from biological body fluids, tissues, or cell lysates, a simple method for homogenization, precipitation of proteins, and protein hydrolysis is described. Since the hydrolysates contain many other components, such as other amino acids, lipids, and nucleic acids, a purification step using solid-phase extraction (SPE) is essential. SPE can either be performed manually using centrifuges or a pipetting robot. The sensitivity for ADMA using the current protocol is about 100 nmol/L. The upper limit of detection for arginine is 3 mmol/L due to SPE saturation. In summary, this protocol describes a robust method, which spans from biological sample preparation to NMR-based detection, providing valuable hints and pitfalls for successful work when studying the arginine methylome.

The present protocol describes the preparation and quantitative measurement of free and protein-bound arginine and methyl-arginines by 1H-NMR spectroscopy.

Arginin Metilomunun Nükleer Manyetik Rezonans Spektroskopisi ile Araştırılması

Protein-bound arginine is commonly methylated in many proteins and regulates their function by altering the physicochemical properties, their interaction ...

Simultaneous Imaging and Flow-Cytometry-based Detection of Multiple Fluorescent Senescence Markers in Therapy-Induced Senescent Cancer Cells

Chemotherapeutic drugs can induce irreparable DNA damage in cancer cells, leading to apoptosis or premature senescence. Unlike apoptotic cell death, senescence is a fundamentally different machinery restraining&#160;propagation of cancer cells. Decades of scientific studies have revealed the complex pathological effects of senescent cancer cells in tumors and microenvironments that modulate cancer cells and stromal cells. New evidence suggests that senescence is a potent prognostic factor during cancer treatment, and therefore rapid and accurate detection of senescent cells in cancer samples is essential. This paper presents a method to visualize and detect therapy-induced senescence (TIS) in cancer cells. Diffuse large B-cell lymphoma (DLBCL) cell lines were treated with mafosfamide (MAF) or daunorubicin (DN) and examined for the senescence marker, senescence-associated &#946;-galactosidase (SA-&#946;-gal), the DNA synthesis marker 5-ethynyl-2&#8242;-deoxyuridine (EdU), and the DNA damage marker gamma-H2AX (&#947;H2AX). Flow cytometer imaging can help generate high-resolution single-cell images in a short period of time to simultaneously visualize and quantify the three markers in cancer cells.

Here we present a flow cytometry-based method for visualization and quantification of multiple senescence-associated markers in single cells.

Tedaviye Bağlı Yaşlanan Kanser Hücrelerinde Çoklu Floresan Yaşlanma Belirteçlerinin Eşzamanlı Görüntüleme ve Akış Sitometrisine Dayalı Tespiti

Chemotherapeutic drugs can induce irreparable DNA damage in cancer cells, leading to apoptosis or premature senescence. Unlike apoptotic cell death, ...