Synergistic activity of agents targeting growth factor receptors, CDKs and downstream signaling molecules in a panel of pancreatic cancer cell lines and the identification of antagonistic combinations: Implications for future clinical trials in pancreatic cancer

Abstract

Pancreatic cancer is one of the most aggressive, heterogeneous and fatal type of human cancers for which more effective therapeutic agents are urgently needed. Here, we investigated the sensitivity of a panel of seven human pancreatic cancer cell lines (HPCCLs) to treatment with various tyrosine kinase inhibitors (TKIs), cyclin-dependent kinase (CDK) inhibitors, an inhibitor of STAT3 stattic, and a cytotoxic agent gemcitabine both as single agents and in combination. The membranous expression of various receptors and the effect of selected agents on cell cycle distribution, cell signaling pathways and migration was determined using flow cytometry, western blot analysis and scratch wound healing assays, respectively. While the expression of both HER-3 and HER-4 was low or negative, the expression of EGFR and HER2 was high or intermediate in all HPCCLs. Of all the agents examined, the CDK1/2/5/9 inhibitor, dinacicilib, was the most potent agent which inhibited the proliferation of all seven HPCCLs with IC 50 values of ≤10 nM, followed by SRC targeting TKI dasatinib (IC 50 of ≤258 nM), gemcitabine (IC 50 of ≤330 nM), stattic (IC 50 of ≤2 µM) and the irreversible pan-HER TKI afatinib (IC 50 of ≤2.95 µM). Treatment with afatinib and dasatinib inhibited the ligand-induced phosphorylation of EGFR and SRC respectively. Statistically significant associations were found between HER2 expression and response to treatment with the ALK/IGF-IR/InsR inhibitor ceritinib and fibroblast growth factor receptor (FGFR)1/2/3 inhibitor AZD4547, HER3 and IGF-IR expression and their response to treatment with TKIs targeting HER family members (erlotinib and afatinib), and c-MET and ALK7 expression and their response to treatment with stattic. Interestingly, treatment with a combination of afatinib with dasatinib and gemcitabine with dasatinib resulted in synergistic tumor growth inhibition in all HPCCLs examined. In contrast, the combination of afatinib with dinaciclib was found to be antagonistic. Finally, the treatment with afatinib, dasatinib and dinaciclib strongly inhibited the migration of all HPCCLs examined. In conclusion, the CDK1/2/5/9 inhibitor dinaciclib, irreversible pan-HER TKI afatinib and SRC targeting TKI dasatinib were most effective at inhibiting the proliferation and migration of HPCCLs and the combination of afatinib with dasatinib and gemcitabine with dasatinib led to synergistic tumor growth inhibition in all HPCCLs examined. Our results support further investigation on the therapeutic potential of these combinations in future clinical trials in pancreatic cancer.

Bioinformatics analysis identified CDC20 as a potential drug target for cholangiocarcinoma

“…The 4 CCA cell lines tested showed different response to gemcitabine as indicated by a wide IC 50 range of 87-241 nM, whereas all cell lines showed a similar sensitivity to dinaciclib with a narrow IC 50 range of 5.4-6.9 nM. Cancers seem to be more sensitive to dinaciclib than gemcitabine as the similar observations were also reported in several pancreatic cancer cell lines (Khan et al, 2020) and hepatocellular carcinoma (Shao et al, 2019;Hassan et al, 2019). The different response of cancer cells to gemcitabine and dinaciclib may be due to the different drug targets and actions.…”

Cyclin Dependent Kinase-1 (CDK-1) Inhibition as a Novel Therapeutic Strategy against Pancreatic Ductal Adenocarcinoma (PDAC)

“…This evidence was confirmed by the study of Parry et al [16] which investigated the effect of dinaciclib on tumour lines of diverse origins, including pancreatic cancer, reported that dinaciclib treatment induced cell cycle arrest, with a relatively high percentage of cells in G2/M phase, at the expense of S phase. In contrast, Khan et al [19] found that treatment of human PDAC cell lines with dinaciclib generally resulted in an increased proportion of cells in the S phase, which is associated with the blockage of CDK2 activity. Since dinaciclib inhibits multiple CDKs, these results may suggest that the effect of the drug is dependent on the mutations present in the PDAC cell type used.…”

“…The proportion of cells in the sub G1 phase was elevated in all cell lines tested, indicating that many cells were in an apoptotic state. Despite the different effect of dinaciclib in the PDAC cell lines, it is possible to say this drug significantly inhibited proliferation of PDAC cells and the drug was identified as a potent cytotoxic agent against PDAC [16,18,19].…”

“…Together, these studies indicate the potential of CDK1 inhibition as a novel drug target to treat PDAC. In addition, several other studies indicate the potential of CDK1 inhibition for both cancer treatment in general [16,17], and specifically for PDAC [18,19].…”

Therapeutic Application of Monoclonal Antibodies in Pancreatic Cancer: Advances, Challenges and Future Opportunities

“…As the results of preclinical and clinical studies discussed above and presented in summary tables suggest, the application of monoclonal antibody-based agents in the treatment of pancreatic cancer is more likely to be successful when used in combination with other therapies such as cytotoxic drugs, other mAbs, cancer vaccines and/or oncolytic viruses. In addition, simultaneous targeting of signalling pathways, the tumour stroma and the incorporation of immune checkpoint inhibitors could yield better results by modifying the immunosuppressive environment of pancreatic tumours [ 70 , 177 , 178 , 179 , 180 , 181 ].…”