The genome of cells is like an instruction book, telling cells what to do and how to do it. Behaviors embedded in the genome of cancer cells can be manipulated to engineer cancer cells into “double agents” and effective treatment vectors. For instance, a behavior known as “tumor self-seeding” is the tendency of cancer cells to leave established tumor sites and recruit circulating cancer cells to be brought back to the original tumor site to fortify their presence in the body by relaying signals amongst each other. Known as the bystander effect, these signals are known to influence surrounding cancer cells. Using CRISPR dCas9 death signals can be embedded in a small group of cancer cells by activating an apoptotic gene (genes that induce cell death). These cells can then act as double agents to broadcast these desirable treatment signals to reduce cancer presence in the body.<br/><br/>To this end MCF7 human breast cancer cells were used. TRAIL was identified as an apoptotic gene effective at inducing cell death. MCF7 cells have an acquired resistance to TRAIL. The native resistance to TRAIL was used to prevent premature cell death of the engineered cells. As such a modified dCas9-VPR cell line emitting TRAIL was engineered by transducing the dCas9 protein through lentiviral delivery into a group of MCF7 cells. Then, a stable line of TRAIL susceptible cells was engineered using SiRNA lipofection. Four groups (MCF-7, dCas9 VPR, TRAIL Susceptible and Co Culture) were established. The dCas9 VPR cells interacted with the TRAIL susceptible cells in the Co cultured well plates at a 1:4 ratio respectively. A neutral red solution was used to stain the engineered dCas9 VPR cells to monitor them and establish a kill switch via ionized quercetin nanoparticles to prevent secondary tumor formation. Quercetin is a natural vitamin that was found to sensitize MCF7 cells to TRAIL’S effects and could be especially promising in a clinical application. An MTT assay was utilized over eight consecutive days to determine cell proliferation -768 trials.<br/><br/>The dCas9 VPR cells-maintained interaction with the TRAIL susceptible cells in the Co cultured well plates. Seven days after the initial co-culture, the group had statistically significantly lowered cancer cell proliferation rates compared with the MCF7 control group (p =2.64E-6). Thus, there could be potential in using modified cancer cells as double agents coupled with quercetin supplements in attacking aggressive tumors throughout the body.

Customized cancer cell weapons: Using CRISPR dCas9 genetic engineering to modify MCF7 human breast cancer cells into double agent treatment vectors

ACS Fall 2021

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