Enhanced anti-colorectal cancer effects of carfilzomib combined with CPT-11 via downregulation of nuclear factor-κB in vitro and in vivo

Abstract

Upregulation of nuclear factor-κB (NF-κB) in colorectal carcinoma (CRC) accelerates tumor growth, whereas, irinotecan (CPT-11)-induced NF-κB activation reduces chemosensitivity and weakens the anti-colorectal cancer function itself, while proteasome inhibitors can inhibit NF-κB and improve the effect of chemotherapy. Carfilzomib (CFZ) is a novel proteasome inhibitor that has been recently approved by the FDA and is in clinical use for the treatment of multiple myeloma, but little is known about its activity against CRC. The aim of the present study was to explore whether CFZ alone or in combination with CPT-11 is effective in CRC treatment. We evaluated the novel therapeutic ability and mechanism of action of CFZ in CRC in vitro and in vivo. SW620 cells were incubated with CFZ alone or in combination with CPT-11. Cell proliferation was assessed by WST-1 and clonogenic assays, the cytotoxic interaction was assessed with a combination index (CI). Cell cycle progression was analysed with flow cytometry. Cell apoptosis was evaluated by detecting the Annexin V/propidium iodide (PI) ratio, caspase 3 and CD95 expression, and with TUNEL staining. Cell migration and invasion was determined with a wound-healing assay and a Transwell matrix penetration assay. A CRC xenograft model was established to monitor tumor growth. EMSA was used to analyse NF-κB activation and western blot analysis was used to detect the protein levels of related signaling factors. CFZ significantly inhibited the growth of SW620 cells, and had synergistic inhibitory effects with CPT-11 on survival and colony formation; possibly by inhibition of NF-κB activation, MEK/ERK and PI3K/AKT pathway factor dephosphorylation and survivin downregulation. Co-administration of CFZ and CPT-11 induced G2/M arrest, increased p21WAF1/CIP, and decreased mutant p53 and cdc25c expression. Induction of apoptosis was accompanied by marked increases in PARP cleavage, caspase 3 activation, an increase of CD95 and p-p38, and ATF3 activation. Combination treatment lowered the invasive and migration ability of SW620 cells, reduced MMP and increased TIMP protein expression. Finally, co-administration of CFZ and CPT-11 suppressed tumor growth and increased apoptosis compared with single-agent treatment in SW620 xenograft models correlated with NF-κB downregulation. Carfilzomib alone or in combination with CPT-11 is effective against colorectal cancer through inhibition of multiple mechanisms related to NF-κB, and could be a potential novel therapy for CRC.

The p38 MAPK Signaling Activation in Colorectal Cancer upon Therapeutic Treatments

“…Conclusively, while it is clear that p38 MAPK is activated upon 5-FU exposure, it appears that a deeper characterization of the molecular players involved in this complex signaling cascade will be needed to exactly define the role of p38 MAPK in the response to this specific agent, and that this will unlock new therapeutic targets for CRC [5] ( Figure 1A). In agreement, CPT-11, when in co-treatments with proteasome inhibitor Carfilzomib (CFZ), revealed increased caspase 3 activity and CD95 expression along with marked increase in p38 MAPK activation in SW620 cells [40].…”

“…In agreement, CPT-11, when in co-treatments with proteasome inhibitor Carfilzomib (CFZ), revealed increased caspase 3 activity and CD95 expression along with marked increase in p38 MAPK activation in SW620 cells [40].…”

Tunable self-assembly of Irinotecan-fatty acid prodrugs with increased cytotoxicity to cancer cells

“…Strikingly, at the highest concentration tested (6 μg mL –1 ), almost no toxicity was observed for Irinotecan, in agreement with the reported work, while Iri-12C NPs completely killed the cancer cells. 35 The difference in the cytotoxicity of Iri-5C NPs, Iri-8C NPs and Iri-12C NPs might be due to the size of the nanoparticles and the length of the fatty acid. The size of the crystal directly affected their intracellular uptake and the length of the fatty acids affected the hydrolysis of the ester bonds of the prodrugs in lysosomes while the dramatic enhancement of the cytotoxicity of the nanoparticles compared to free Irinotecan was considered to be the consequence of increased intracellular accumulation of the nano-formulations.…”

Identification of the anticancer effects of a novel proteasome inhibitor, ixazomib, on colorectal cancer using a combined method of microarray and bioinformatics analysis

“… 54 Moreover, ATF3 plays a driving role in various drugs induced apoptosis in CRC. 55 – 57 According to the microarray analysis, ATF3 was significantly upregulated as a result of ixazomib treatment (log 2 FC =2.0248, adjusted P -value =2.32E−05), indicating that ixazomib exerts an antitumor function by elevating the expression of ATF3 , inducing cell cycle arrest, and apoptosis in CRC.…”