## 2 Results
### MYC Targeting by CRISPR-Cas9 Gene Editing
\begin{tabular}{c} CTCCCTTCGGGGAGACAAC.CGGCGGGGGGAGCTTCTCCACAGGGC \\ CTCCCTTTGGGAGACAAC....GTGTGGGGGGAGCTTCTCCACAGGGC \\ \end{tabular}  & \(-2\) \\ \hline Clone \#4 &
\begin{tabular}{c} CTCC....GGGGGGGGGGAGCTTCTCCACAGGGC \\ CTCCCTTTG  
Figure 2: MYC downregulation increases rituximab-dependent cellular cytotoxicity and increases CD20 expression. (**A**) Immunoblot analysis of MYC protein and \(\beta\)-actin levels in OCI-LY18 wild type  
(WT) and MYC-targeted clones. Immunoblot is representative of three independent experiments. (**B**) OCI-LY18 WT (black) and MYC-targeted clones (colored) were incubated with indicated concentrations of rituximab (x-axis) in the presence of PBMCs obtained from healthy donors as effector cells (E:T ratio 40:1) for 16 h. Percentage of tumor cell lysis is depicted on the y-axis. Tumor cell lysis was assessed using a flow cytometry-based cytotoxicity assay. Cell lysis was calculated within each cell line compared to untreated cells. Data are presented as mean \(\pm\) SEM of at least 3 technical replicates. (**C**) Representative flow-cytometry histogram depicting CD20 expression (left) and corresponding mean fluorescent values (MFI) (right) in OCI-LY18 WT (black) and MYC-targeted clones (colored). Expression data are representative histograms of at least 2 technical replicates. (**D**) Correlation plot of rituximab-induced EC50 values (x-axis) versus CD20 expression (as MFI values [y-axis]) in OCI-LY18 WT (black) and MYC-targeted clones (colored). (**E**) Immunoblot analysis of MYC protein and \(\beta\)-actin levels in OCI-LY18 WT and MYC-targeted clone #1 and MYC-repaired subclones (R1 and R2). Immunoblot is representative of three independent experiments. (**F**) Cytotoxicity of OCI-LY18 WT (black) and MYC-targeted clone #1 (red) and MYC-repaired subclones (grey) following rituximab treatment. Details as in (**B**). (**G**) Representative flow-cytometry histogram depicting CD20 expression (left) and corresponding mean fluorescent values (MFI) (right) in OCI-LY18 WT (black) and MYC-targeted clone #1 (red) and MYC-repaired subclones (grey). *_p_ < 0.05; **_p_ < 0.01; ns not significant. Increased Sensitivity Towards Conventional and T Cell-Redirected Cytotoxicity Beyond Target Antigen Expression Following MYC Downregulation  
We also tested whether the efficacy of the monoclonal anti-CD38 antibody darantumumab and the CD3 xCD19 bispecific T-cell engager blinatumomab could be improved  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Clones** & **S\({}^{\prime}\) MYC-1 Target Site 3\({}^{\prime}\)** & **Basepair Nr** \\ \hline \hline \multirow{6}{*}{Clone 1} & CCGGCTCTCTCCCCCTACCTTCCGGCTACACCCTTCTCC & \\  & CTTGGGAGACAACGACGGCGGCGGGGA & \\ \cline{2-3}  & CCCGGGCCTCTCTCCCCCTCACCTTCCCGTCACACCCTTCTCC & \(-\)1 \\ \cline{2-3}  & GGGGACAACGCCGGCGGCGGA & \(-\)6 \\ \cline{2-3}  & CCCGGGCCTCTGCCTCCCCTCCTCGCGTCACACCCTTCC & \\  & CTTCCGGGGAGACAACG....GTGCGCGGA & \\ \hline \multirow{6}{*}{All subclones  Following repair} & CCGGCTCTCTCTCCCTTACGTCCGTCTACACCC & \\  & TCTCCCTTCGGTAGATAATGCCGCCGGCGGA & \\ \cline{1-1}  & CCGGCTCTCTCTCCCCCTACGGTTCCby CRISPR-Cas9-mediated MYC downregulation. Similar to the rituximab setting, we first confirmed that Cas9 transduction did not influence daratumumab-mediated cytotoxicity (Figure S3C). Interestingly, daratumumab-mediated ADCC was enhanced in the same MYC downregulated clones as parental OCI-LY18 WT cells (Figure 3A) as well as blinatumomab-mediated T cell-dependent cytotoxicity in a selection of representative MYC downregulated clones tested (Figure 3B). Daratumumab- and blinatumomab-mediated cytotoxicity was completely reversed in MYC-repaired subclones, confirming the direct involvement of MYC (Figure 3C,D). Cas9 transduction did not influence CD38 or CD19 expression in parental OCI-Y18 WT cells (Figure S3C), and MYC downregulated clones displayed equal or reduced expression levels of target antigens for daratumumab (CD38) and blinatumomab (CD19) compared to parental OCI-LY18 WT cells (Figure 3E).