BRD4 Inhibitor AZD5153 Suppresses the Proliferation of Colorectal Cancer Cells and Sensitizes the Anticancer Effect of PARP Inhibitor

Abstract

Background: Bromodomain-containing protein 4(BRD4) is reported to play a vital role in the development of numerous malignant diseases, which is considered as a promising target for cancer therapy. AZD5153, a novel specific BRD4 inhibitor, showed potent anticancer effects in several cancer types, but its therapeutic potential has not been fully evaluated in colorectal cancer cells.Objective: We sought to evaluate the therapeutic potential of BRD4 inhibition of by AZD5153 and its combined anticancer cancer effect with PARP inhibitor BMN673 in vitro and in vivo in colorectal cancer.Methods: We analyzed The Cancer Genome Atlas (TCGA) database to investigate BRD4 expression in colorectal cancer patient. Clonogenic assays 、MTT assays and PI/Annexin V staining were used to determine the effect of AZD5153 and BMN673 and combination therapy on cell viability and apoptosis induction. Western blotting was applied to detect relevant molecules changes. Propidium iodide staining was performed to examine cell cycle distributions after monotherapy or combination therapy. Nude mice xenograft model was generated to confirm the therapeutic effect of AZD5153 and BMN673 combination in vivo, and IHC staining was used to detect the expression level of BRD4 and related markers in colorectal patient and xenograft.Results: Analysis of TCGA database indicated that BRD4 was overexpressed in colorectal cancer patient. The clonogenic and MTT assays and PI/Annexin V staining demonstrated that AZD5153 significantly suppressed cell proliferation and induced apoptosis in colorectal cancer cells HCT116 and LoVo. Western blotting showed that AZD5153 inhibited the expression of c-Myc and increased expression of the apoptosis markers, cleaved caspase-3 and poly(ADP-ribose) polymerase (PARP), besides, we found that BRD4 knockdown could also inhibited cell proliferation and induced cell apoptosis. Moreover, AZD5153 inhibited the expression of Wee1 and impaired G2M cell cycle checkpoint, thus sensitized the anticancer effect of BMN673 in vitro and in vivo.Conclusion: Our data revealed that AZD5153suppressed the proliferation of colorectal cancer cells and sensitized them to the anticancer effect of the PARP inhibitor BMN673 via Wee1 inhibition in vitro and in vivo. This suggested that targeting BRD4 might be a valuable strategy for colorectal cancer treatment.

Exosomal circLPAR1 functions in colorectal cancer diagnosis and tumorigenesis through suppressing BRD4 via METTL3–eIF3h interaction

“…BRD4 , a member of the bromodomain and extra-terminal domain (BET) family, plays a crucial role in the development of multiple cancers and is regarded as a novel cancer therapeutic target [ 40 , 41 ]. In addition, BRD4 has been shown to promote the proliferation of colorectal cancer cells, while the BRD4 inhibitor AZD5153 reversed this effect [ 42 ]. Our results extended the findings showing that exosomal circLPAR1 binds eIF3h to inhibit the METTL3–eIF3h interaction, which decreases the translation of BRD4 , thereby suppressing colorectal cancer cell proliferation, invasion and migration, and experiments with in vivo models showed consistent results.…”

Systematic Analysis of Molecular Characterization and Clinical Relevance of Liquid–Liquid Phase Separation Regulators in Digestive System Neoplasms

“…For example, BRD4 stabilizes the progression of stomach cancer through Snail ( Qin et al, 2019 ) and promotes the stemness of gastric cancer cells by inhibiting Wnt/β-catenin signal transduction ( Song et al, 2019 ). Using inhibitor AZD5153 to inhibit BRD4 can inhibit the proliferation of colorectal cancer cells ( Zhang et al, 2019 ). To the best of our knowledge, this is the first study that shows that “LLPS regulators” may play a key role in regulating the development of digestive system tumors.…”

Constructing the ceRNA Regulatory Network and Combining Immune Cells to Evaluate Prognosis of Colon Cancer Patients

“…The 5-year survival rate of patients with stage I can reach more than 90% (Heagerty et al, 2000;Yoshihara et al, 2013;Newman et al, 2015), but for patients with metastasis, the 5-year survival rate is only 10%-20%. Therefore, the mortality rate of colon cancer is the second highest in the world (Engelhardt et al, 2017;Peng et al, 2019). Surgical resection and chemotherapy are the routine treatment for patients with colon cancer, but in one study, patients with colon cancer after conventional treatment still showed a high recurrence rate and mortality (Weinberg et al, 2017).…”