HDAC6 and plasma cell myeloma: Consistent with pharmacological inhibition, silencing HDAC6 using short‐hairpin RNA (shRNA) and CRISPR‐Cas9 significantly decreased GS protein levels compared to the non‐targeting (NT) controls in U251 cells (Figure S3D,E, Supporting Information) and various other cancer cells, including HCT116 (colorectal cancer), PC3 (prostate cancer), MM.1s (multiple myeloma), and SKOV3 (ovarian cancer) (Figure S3F–I, Supporting Information).