Name: identification of egfr and ras inhibitors using caenorhabditis elegans
Uploaded: 2020-10-05T14:00:00
Description: Watch this Scientific Journal Video about Identification of EGFR and RAS Inhibitors using Caenorhabditis elegans at JoVE.com

We thank Dr. Swathi Arur (MD Anderson Cancer Center) for providing the let-60(n1046). We also thank Dr. David Reiner (Texas A&#38;M Health Science Center Institute of Biosciences &#38; Technology in Houston) for the lin-1 strain. Finally, we thank Dr. Danielle Garsin and her lab (The University of Texas, McGovern Medical School) for providing some of the reagents. Some worm strains were provided by the CGC, which is funded by NIH Office of Research Infrastructure Programs (P40 OD010440). This Research was supported by the Cancer Prevention and Research Institute of Texas (CPRIT) grant RP200047 to JF Hancock.

1. Nematode growth medium (NGM) plate preparation
<ol>
	<li>Add 2.5 g of peptone and 3 g of NaCl to 970 mL of deionized water contained in a 2 L Erlenmeyer flask. Stir contents using a magnetic stir bar. Thereafter, add 20 g of agar to the flask. Autoclave the contents of the flask at 121 &#176;C and a pressure of 15 lb/in2 for 30 min. After sterilization, place the flask on a stir plate and allow the medium to cool until the temperature reaches 50 &#176;C.</li>
	<li>To prepare the NGM plates add the followi...

<ol>
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(64), e4019 (2012).</li><li>Stiernagle, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Maintenance+of+C.+elegans.">Maintenance of C. elegans.</a> WormBook. , 1-11 (2006).</li><li>Revtovich, A. V., Lee, R., Kirienko, N. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interplay+between+mitochondria+and+diet+mediates+pathogen+and+stress+resistance+in+Caenorhabditis+elegans.">Interplay between mitochondria and diet mediates pathogen and stress resistance in Caenorhabditis elegans.</a> PLoS Genetics. 15 (3), 1008011 (2019).</li><li>Zimmermann, M., Zimmermann-Kogadeeva, M., Wegmann, R., Goodman, A. 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The assays we describe using the worm are simple and inexpensive to identify inhibitors of EGFR and RAS function. C. elegans is an attractive model for drug discovery because it is easy to grow in the lab due to the short life cycle (3 days at 20 &#176;C) and the ability to generate large numbers of larvae. More importantly, the EGFR-RAS-ERK MAPK pathway is evolutionarily and functionally conserved with mammals providing a genetically tractable system to analyze the effects of EGFR and RAS inhibitors. Further, t...

The cellular pathways that regulate developmental events within organisms are highly conserved among all metazoans. One such pathway is the EGFR-RAS-ERK mitogen activated protein kinase (MAPK) signaling cascade which is a critical pathway that governs cell proliferation, differentiation, migration and survival1,2. Defects in this signaling pathway can lead to pathological or disease states such as cancer. The epidermal growth factor receptor (EGFR) has shown to be highly expressed in human tumors, including 50% of oral squamous cell carcinomas, and contributes to the development of malignant tumors3,4,5. Whereas mutations in the three RAS isoforms H-, K- and N-RAS are major drivers for malignant transformation in multiple human cancers. Amongst these three RAS isoforms, oncogenic mutations in K-RAS are most prevalent6,7,8. For EGFR and RAS to function, they must localize to the plasma membrane (PM). Preventing the localization of these molecules to the PM can completely abrogate the biological activity of this signal pathway9,10. Hence the inhibition of the localization of these proteins to the PM is a therapeutic strategy to block the downstream signaling and the resulting adverse outcomes. Using a high-content screening assay, fendiline, an L-type calcium channel blocker, was identified as an inhibitor of K-RAS activity11. Nanoclustering of K-RAS to the inner leaflet of the PM is significantly reduced in the presence of fendiline. Furthermore, K-RAS is redistributed from the plasma membrane to the endoplasmic reticulum (ER), Golgi apparatus, endosomes, and cytosol. More importantly, the proliferation of pancreatic, colon, lung, and endometrial cancer cell lines expressing oncogenic mutant K-RAS is blocked by the inhibition of downstream signaling by fendiline11. These data suggest fendiline functions as a specific K-RAS anticancer therapeutic that causes the mis-localization of the RAS protein to the PM.
The nematode Caenorhabditis elegans has been extensively studied in the context of development. Many of the signal pathways that govern development in the worm are evolutionary and functionally conserved. For example, the EGFR mediated activation of RAS and the subsequent activation of the ERK MAPK signal cascade is conserved in the worm12. The cascade is represented by the following proteins: LET-23 &#62; LET-60 &#62; LIN-45 &#62; MEK-2 &#62; MPK-1. LET-60 is homologous to RAS, while LET-23 is homologous to EGFR. In the worm, this pathway regulates the development of the vulva13. The vulva is an epithelial aperture on the ventral body wall of the worm that allows fertilized eggs to be laid. The formation of the vulva in the worm is dependent on the exposure of the vulval precursor cells (VPC) to a gradient of activation of the EGFR-RAS-MAPK signal cascade. During the normal development, the proximal VPCs receive strong signals from the gonadal anchor cells to differentiate into 1&#176; and 2&#176; cell fates which give rise to a functional vulva12. Whereas distal VPCs differentiate into 3&#176; cell fates that fuse to the hypodermal syncytium and do not form vulva due to depleted signaling. In the absence of signaling, all VPCs differentiate into 3&#176; cell fates resulting in the formation of no vulva. However, constitutive signaling leads to the formation one or more non-functional vulva due to the induction of all VPCs to assume&#160;1&#176; and 2&#176; cell fates.
Mutations that cause defective or excessive vulval induction have been identified for many of the genes that encode for proteins representing this pathway. Defective vulval induction results in a vulvaless (Vul) phenotype, while excessive vulval induction results in a multivulva (Muv) phenotype that is represented by the development of numerous nonfunctional ectopic pseudovulvae throughout the ventral body wall. The Muv phenotype expressed by the let-60(n1046) strain is due to a gain of function mutation in RAS, while in the let-23(sa62) strain it is due an activating mutation in EGFR14,15. The strong Muv phenotype in these mutant strains has been shown to be perturbed by pharmacological interventions as demonstrated by the treatment of let-60(n1046) worms with the MEK-1 inhibitor U012616,17. Interestingly, we have shown that R-fendiline and inhibitors that affect sphingomyelin metabolism suppress the Muv phenotype in the worm18. To demonstrate these inhibitors block let-60 signaling at the level of RAS, the lin-1 null strain has been utilized17. Lin-1 is an Ets-like inhibitory transcription factor that functions as a repressor in the development of the vulva19. Strong reversion of the Muv phenotype in let-60(n1046) worms and no effect on lin-1 null worms suggest that these inhibitions occur at the level of RAS.
In this protocol, we demonstrate the use of C. elegans as a model to identify inhibitors of RAS and EGFR proteins. Using a liquid-based assay, we demonstrate the inhibitory effects of R-fendiline by suppressing the Muv phenotypes in the let-60(n1046) and let-23(sa62) mutant strains of C. elegans. This assay validates the use of C. elegans as a tool in the initial phase of drug discovery for anticancer therapeutics.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Media and chemicals</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Agarose&#160;</td>
			<td>Millipore Sigma&#160;</td>
			<td>A9539-50G</td>
			<td></td>
		</tr>
		<tr>
			<td>Bacto Peptone&#160;</td>
			<td>Fisher Scientific</td>
			<td>DF0118-17-0</td>
			<td></td>
		</tr>
		<tr>
			<td>BD Difco Agar&#160;</td>
			<td>Fisher Scientific</td>
			<td>DF0145-17-0</td>
			<td></td>
		</tr>
		<tr>
			<td>BD Difco LB Broth</td>
			<td>Fisher Scientific</td>
			<td>DF0446-17-3</td>
			<td></td>
		</tr>
		<tr>
			<td>Calcium Chloride</td>
			<td>Fisher Scientific</td>
			<td>BP510-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Cholesterol</td>
			<td>Fisher Scientific</td>
			<td>ICN10138201</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnesium Sulfate</td>
			<td>Fisher Scientific</td>
			<td>BP213-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Nystatin</td>
			<td>Acros organics</td>
			<td>AC455500050</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium Phosphate Dibasic</td>
			<td>Fisher Scientific</td>
			<td>BP363-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium pPhosphate Monobasic</td>
			<td>Fisher Scientific</td>
			<td>BP362-500</td>
			<td></td>
		</tr>
		<tr>
			<td>R-Fendiline</td>
			<td></td>
			<td></td>
			<td>Commercially Synthesized (Pharmaceutical grade)</td>
		</tr>
		<tr>
			<td>Sodium Azide</td>
			<td>Millipore Sigma&#160;</td>
			<td>S2002-25G</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium chloride&#160;</td>
			<td>Fisher Scientific</td>
			<td>BP358-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Hydroxide</td>
			<td>Fisher Scientific</td>
			<td>SS266-1</td>
			<td></td>
		</tr>
		<tr>
			<td>8.25% Sodium Hypochlorite&#160;</td>
			<td></td>
			<td></td>
			<td>Bleach</td>
		</tr>
		<tr>
			<td>Sodium Phosphate Dibasic&#160;</td>
			<td>Fisher Scientific</td>
			<td>BP332-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Streptomycin Sulfate&#160;</td>
			<td>Fisher Scientific</td>
			<td>BP910-50</td>
			<td></td>
		</tr>
		<tr>
			<td>(&#8722;)-Tetramisole Hydrochloride</td>
			<td>Millipore Sigma&#160;</td>
			<td>L9756</td>
			<td></td>
		</tr>
		<tr>
			<td>UO126 (MEK inhibitor)</td>
			<td>Millipore Sigma&#160;</td>
			<td>19-147</td>
			<td></td>
		</tr>
		<tr>
			<td>Consumables&#160;</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>15mL Conical Sterile Polypropylene Centrifuge Tubes&#160;</td>
			<td>Fisher Scientific</td>
			<td>12-565-269</td>
			<td></td>
		</tr>
		<tr>
			<td>50mL Conical Sterile Polypropylene Centrifuge Tubes</td>
			<td>Fisher Scientific</td>
			<td>12-565-271</td>
			<td></td>
		</tr>
		<tr>
			<td>Disposable Polystyrene Serological Pipettes 10mL</td>
			<td>Fisher Scientific</td>
			<td>07-200-574</td>
			<td></td>
		</tr>
		<tr>
			<td>Disposable Polystyrene Serological Pipettes 25mL</td>
			<td>Fisher Scientific</td>
			<td>07-200-575</td>
			<td></td>
		</tr>
		<tr>
			<td>No. 1.5&#160; 18 mm X 18 mm Cover Slips</td>
			<td>Fisher Scientific</td>
			<td>12-541A</td>
			<td></td>
		</tr>
		<tr>
			<td>Petri Dish with Clear Lid (60 x 15 mm)</td>
			<td>Fisher Scientific</td>
			<td>FB0875713A</td>
			<td></td>
		</tr>
		<tr>
			<td>Petri Dishes with Clear Lid (100X15mm)</td>
			<td>Fisher Scientific</td>
			<td>FB0875712</td>
			<td></td>
		</tr>
		<tr>
			<td>Plain Glass Microscope Slides (75 x 25 mm)</td>
			<td>Fisher Scientific</td>
			<td>12-544-4</td>
			<td></td>
		</tr>
		<tr>
			<td>12- Well Tissue Culture Plates</td>
			<td>Fisher Scientific</td>
			<td>50-197-4804</td>
			<td></td>
		</tr>
		<tr>
			<td>Software&#160;</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Prism</td>
			<td>Graphpad</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Bacterial Strains</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>E. coli OP50</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Worm Strains</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Strain</td>
			<td>Genotype</td>
			<td>Transgene</td>
			<td>Source</td>
		</tr>
		<tr>
			<td>MT2124 &#160;</td>
			<td>let-60(n1046) IV.</td>
			<td></td>
			<td>CGC</td>
		</tr>
		<tr>
			<td>MT7567</td>
			<td>lin-1(sy254) IV.</td>
			<td></td>
			<td>CGC</td>
		</tr>
		<tr>
			<td>PS1839</td>
			<td>let-23(sa62) II.</td>
			<td></td>
			<td>CGC</td>
		</tr>
	</tbody>
</table>

identification of egfr and ras inhibitors using caenorhabditis elegans

The changes in the plasma membrane localization of the epidermal growth factor receptor (EGFR) and its downstream effector RAS have been implicated in several diseases including cancer. The free-living nematode C. elegans possesses an evolutionary and functionally conserved EGFR-RAS-ERK MAP signal cascade which is central for the development of the vulva. Gain of function mutations in RAS homolog LET-60 and EGFR homolog LET-23 induce the generation of visible nonfunctional ectopic pseudovulva along the ventral body wall of these worms. Previously, the multivulval (Muv) phenotype in these worms has been shown to be inhibited by small chemical molecules. Here we describe a protocol for using the worm in a liquid-based assay to identify inhibitors that abolish the activities of EGFR and RAS proteins. Using this assay, we show R-fendiline, an indirect inhibitor of K-RAS, suppresses the Muv phenotype expressed in the let-60(n1046) and let-23(sa62) mutant worms. The assay is simple, inexpensive, is not time consuming to setup, and can be used as an initial platform for the discovery of anticancer therapeutics.

We first demonstrate that R-fendiline is able to suppress the Muv phenotype in the let-60(n1046) mutant strain compared to the DMSO treated worms. Our data shows that R-fendiline is able to block the Muv phenotype in the let-60(n1046) in a dose-dependent manner (Figure 2A,B). However, non-reversal of the Muv phenotype was observed in the lin-1 null mutant strain in response to increasing concentrations of R-fendiline (Figure 2B...

Watch this Scientific Journal Video about Identification of EGFR and RAS Inhibitors using Caenorhabditis elegans at JoVE.com

Identification of EGFR and RAS Inhibitors using Caenorhabditis elegans

The genetically tractable nematode Caenorhabditis elegans can be used as a simple and inexpensive model for drug discovery. Described here is a protocol to identify anticancer therapeutics that inhibit the downstream signaling of RAS and EGFR proteins.

Identification of EGFR and RAS Inhibitors using Caenorhabditis elegans

The changes in the plasma membrane localization of the epidermal growth factor receptor (EGFR) and its downstream effector RAS have been implicated in ...

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Sectioning Mammary Gland Whole Mounts for Lesion Identification

Normal mammary gland development may be altered by exposure to environmental toxicants and pharmaceutical products, excessive exposure to hormones, and ...

Identification and Characterization of Metastatic Factors by Gene Transfer into the Novel RIP-Tag; RIP-tva Murine Model

Identification and Characterization of Metastatic Factors by Gene Transfer into the Novel RIP-Tag; RIP-tva Murine Model

Metastatic cancer accounts for 90% of deaths in patients with solid tumors. There is an urgent need to better understand the drivers of cancer metastasis ...

Establishing Dual Resistance to EGFR-TKI and MET-TKI in Lung Adenocarcinoma Cells In Vitro with a 2-step Dose-escalation Procedure

Establishing Dual Resistance to EGFR-TKI and MET-TKI in Lung Adenocarcinoma Cells In Vitro with a 2-step Dose-escalation Procedure

Drug resistance is a major challenge in cancer therapy. The generation of resistant sublines in vitro is necessary for discovering novel mechanisms to ...

Identification of OTX1 and OTX2 As Two Possible Molecular Markers for Sinonasal Carcinomas and Olfactory Neuroblastomas

OTX homeobox (HB) genes are expressed during embryonic morphogenesis and during the development of olfactory epithelium in adult organisms. Mutations ...

Assessment of Resistance to Tyrosine Kinase Inhibitors by an Interrogation of Signal Transduction Pathways by Antibody Arrays

Cancer patients with an aberrant regulation of the protein phosphorylation networks are often treated with the tyrosine kinase inhibitors. Response rates ...

Identification, Histological Characterization, and Dissection of Mouse Prostate Lobes for In Vitro 3D Spheroid Culture Models

Genetically engineered mouse models (GEMMs) serve as effective pre-clinical models for investigating most types of human cancers, including prostate ...

Characterization of the Effects of Migrastatic Inhibitors on 3D Tumor Spheroid Invasion by High-resolution Confocal Microscopy

Drug discovery and development in cancer research is increasingly being based on drug screens in a 3D format. Novel inhibitors targeting the migratory and ...

Identification of Transcription Factor Regulators using Medium-Throughput Screening of Arrayed Libraries and a Dual-Luciferase-Based Reporter

Transcription factors can alter the expression of numerous target genes that influence a variety of downstream processes making them good targets for ...

Assays for Validating Histone Acetyltransferase Inhibitors

Lysine acetyltransferases (KATs) catalyze acetylation of lysine residues on histones and other proteins to regulate chromatin dynamics and gene ...

Assessing Cellular Target Engagement by SHP2 (PTPN11) Phosphatase Inhibitors

Assessing Cellular Target Engagement by SHP2 PTPN11 Phosphatase Inhibitors

The Src-homology 2 (SH2) domain-containing phosphatase 2 (SHP2), encoded by the PTPN11 proto-oncogene, is a key mediator of receptor tyrosine kinase ...