The IGF-1R Inhibitor NVP-AEW541 Causes Insulin-Independent and Reversible Cardiac Contractile Dysfunction.

The antitumor treatment NVP-AEW541 blocks IGF-1R. IGF-1R signaling is crucial for cardiac function, but the cardiac effects of NVP-AEW541 are ill defined. We assessed NVP-AEW541's effects on cardiac function and insulin response in vivo and in isolated working hearts. We performed a dose-response analysis of NVP-AEW541 in male, 3-week-old rats and assessed the chronic effects of the clinically relevant dose in adult rats. We performed glucose tolerance tests and echocardiography; assessed the expression and phosphorylation of InsR/IGF-1R and Akt in vivo; and measured substrate oxidation, contractile function, and insulin response in the isolated working hearts. NVP-AEW541 caused dose-dependent growth retardation and impaired glucose tolerance in the juvenile rats. In the adults, NVP-AEW541 caused a continuously worsening depression of cardiac contractility, which recovered within 2 weeks after cessation. Cardiac Akt protein and phosphorylation were unchanged and associated with InsR upregulation. An acute application of NVP-AEW541 in the working hearts did not affect cardiac power but eliminated insulin's effects on glucose and fatty acid oxidation. The systemic administration of NVP-AEW541 caused dose- and time-dependent impairment of glucose tolerance, growth, and cardiac function. Because cardiac insulin signaling was maintained in vivo but absent in vitro and because contractile function was not affected in vitro, a direct link between insulin resistance and contractile dysfunction appears unlikely.

Two old drugs, NVP-AEW541 and GSK-J4, repurposed against the Toxoplasma gondii RH strain.

BACKGROUND: Toxoplasma gondii is a zoonotic pathogen that causes toxoplasmosis and leads to serious public health problems in developing countries. However, current clinical therapeutic drugs have some disadvantages, such as serious side effects, a long course of treatment and the emergence of drug-resistant strains. The urgent need to identify novel anti-Toxoplasma drugs has initiated the effective strategy of repurposing well-characterized drugs. As a principled screening for the identification of effective compounds against Toxoplasma gondii, in the current study, a collection of 666 compounds were screened for their ability to significantly inhibit Toxoplasma growth. METHODS: The inhibition of parasite growth was determined using a luminescence-based ß-galactosidase activity assay. Meanwhile, the effect of compounds on the viability of host cells was measured using CCK8. To assess the inhibition of the selected compounds on discrete steps of the T. gondii lytic cycle, the invasion, intracellular proliferation and egress abilities were evaluated. Finally, a murine infection model of toxoplasmosis was used to monitor the protective efficacy of drugs against acute infection of a highly virulent RH strain. RESULTS: A total of 68 compounds demonstrated more than 70% parasite growth inhibition. After excluding compounds that impaired host cell viability, we further characterized two compounds, NVP-AEW541 and GSK-J4 HCl, which had IC50 values for parasite growth of 1.17 µM and 2.37 µM, respectively. In addition, both compounds showed low toxicity to the host cell. Furthermore, we demonstrated that NVP-AEW541 inhibits tachyzoite invasion, while GSK-J4 HCl inhibits intracellular tachyzoite proliferation by halting cell cycle progression from G1 to S phase. These findings prompted us to analyse the efficacy of the two compounds in vivo by using established mouse models of acute toxoplasmosis. In addition to prolonging the survival time of mice acutely infected with T. gondii, both compounds had a remarkable ability to reduce the parasite burden of tissues. CONCLUSIONS: Our findings suggest that both NVP-AEW541 and GSK-J4 could be potentially repurposed as candidate drugs against T. gondii infection.

Inhibition of PI3K/Akt/mTOR overcomes cisplatin resistance in the triple negative breast cancer cell line HCC38.

BACKGROUND: Widely established targeted therapies directed at triple negative breast cancer (TNBC) are missing. Classical chemotherapy remains the systemic treatment option. Cisplatin has been tested in TNBC but bears the disadvantage of resistance development. The purpose of this study was to identify resistance mechanisms in cisplatin-resistant TNBC cell lines and select targeted therapies based on these findings. METHODS: The TNBC cell lines HCC38 and MDA-MB231 were subjected to intermittent cisplatin treatment resulting in the 3.5-fold cisplatin-resistant subclone HCC38CisR and the 2.1-fold more resistant MDA-MB231CisR. Activation of pro-survival pathways was explored by immunostaining of phospho-receptor tyrosine kinases. Targeted therapies (NVP-AEW541, lapatinib and NVP-BEZ235) against activated pathways were investigated regarding cancer cell growth and cisplatin sensitivity. RESULTS: In HCC38CisR and MDA-MB231CisR, phosphorylation of epidermal growth factor receptor (EGFR) and insulin-like growth factor 1 receptor (IGF1R) was observed. In HCC38CisR, treatment with NVP-AEW541 increased potency of lapatinib almost seven-fold, but both compounds could not restore cisplatin sensitivity. However, the dual phosphoinositide 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) inhibitor NVP-BEZ235 acted synergistically with cisplatin in HCC38CisR and fully restored cisplatin sensitivity. Similarly, NVP-BEZ235 increased cisplatin potency in MDA-MB231CisR. Furthermore, NVP-AEW541 in combination with lapatinib restored cisplatin sensitivity in MDA-MB231CisR. CONCLUSION: Simultaneous inhibition of EGFR and IGF1R in cisplatin-resistant TNBC cell lines was synergistic regarding inhibition of proliferation and induction of apoptosis. Co-treatment with NVP-BEZ235 or with a combination of NVP-AEW541 and lapatinib restored cisplatin sensitivity and may constitute a targeted treatment option for cisplatin-resistant TNBC.

Receptors for Insulin-Like Growth Factor-2 and Androgens as Therapeutic Targets in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) occurs in 10-15% of all breast cancer patients, yet it accounts for about half of all breast cancer deaths. There is an urgent need to identify new antitumor targets to provide additional treatment options for patients afflicted with this aggressive disease. Preclinical evidence suggests a critical role for insulin-like growth factor-2 (IGF2) and androgen receptor (AR) in regulating TNBC progression. To advance this work, a panel of TNBC cell lines was investigated with all cell lines showing significant expression of IGF2. Treatment with IGF2 stimulated cell proliferation in vitro (p < 0.05). Importantly, combination treatments with IGF1R inhibitors BMS-754807 and NVP-AEW541 elicited significant inhibition of TNBC cell proliferation (p < 0.001). Based on Annexin-V binding assays, BMS-754807, NVP-AEW541 and enzalutamide induced TNBC cell death (p < 0.005). Additionally, combination of enzalutamide with BMS-754807 or NVP-AEW541 exerted significant reductions in TNBC proliferation even in cells with low AR expression (p < 0.001). Notably, NVP-AEW541 and BMS-754807 reduced AR levels in BT549 TNBC cells. These results provide evidence that IGF2 promotes TNBC cell viability and proliferation, while inhibition of IGF1R/IR and AR pathways contribute to blockade of TNBC proliferation and promotion of apoptosis in vitro.

Insulin-like growth factors inhibit dendritic cell-mediated anti-tumor immunity through regulating ERK1/2 phosphorylation and p38 dephosphorylation.

Insulin-like growth factors (IGFs) can promote tumorigenesis via inhibiting the apoptosis of cancer cells. The relationship between IGFs and dendritic cell (DC)-mediated immunity were investigated. Advanced-stage ovarian carcinoma patients were first evaluated to show higher IGF-1 and IGF-2 concentrations in their ascites than early-stage patients. IGFs could suppress DCs' maturation, antigen presenting abilities, and the ability to activate antigen-specific CD8(+) T cell. IGF-treated DCs also secreted higher concentrations of IL-10 and TNF-α. IGF-treated DCs showed decreased ERK1/2 phosphorylation and reduced p38 dephosphorylation. The percentages of matured DCs in the ascites were significantly lower in the IGF-1 or IGF-2 highly-expressing WF-3 tumor-bearing mice. The IGF1R inhibitor - NVP-AEW541, could block the effects of IGFs to rescue DCs' maturation and to restore DC-mediated antigen-specific immunity through enhancing ERK1/2 phosphorylation and p38 dephosphorylation. IGFs can inhibit DC-mediated anti-tumor immunity through suppressing maturation and function and the IGF1R inhibitor could restore the DC-mediated anti-tumor immunity. Blockade of IGFs could be a potential strategy for cancer immunotherapy.

EGFR and IGF-1R in regulation of prostate cancer cell phenotype and polarity: opposing functions and modulation by T-cadherin.

T-cadherin is an atypical glycosylphosphatidylinsoitol-anchored member of the cadherin superfamily of adhesion molecules. We found that T-cadherin overexpression in malignant (DU145) and benign (BPH-1) prostatic epithelial cell lines or silencing in the BPH-1 cell line, respectively, promoted or inhibited migration and spheroid invasion in collagen I gel and Matrigel. T-cadherin-dependent effects were associated with changes in cell phenotype: overexpression caused cell dissemination and loss of polarity evaluated by relative positioning of the Golgi/nuclei in cell groups, whereas silencing caused formation of compact polarized epithelial-like clusters. Epidermal growth factor receptor (EGFR) and IGF factor-1 receptor (IGF-1R) were identified as mediators of T-cadherin effects. These receptors per se had opposing influences on cell phenotype. EGFR activation with EGF or IGF-1R inhibition with NVP-AEW541 promoted dissemination, invasion, and polarity loss. Conversely, inhibition of EGFR with gefitinib or activation of IGF-1R with IGF-1 rescued epithelial morphology and decreased invasion. T-cadherin silencing enhanced both EGFR and IGF-1R phosphorylation, yet converted cells to the morphology typical for activated IGF-1R. T-cadherin effects were sensitive to modulation of EGFR or IGF-1R activity, suggesting direct involvement of both receptors. We conclude that T-cadherin regulates prostate cancer cell behavior by tuning the balance in EGFR/IGF-1R activity and enhancing the impact of IGF-1R.

IGF1R tyrosine kinase inhibitor enhances the cytotoxic effect of methyl jasmonate in endometrial cancer.

The present study evaluated the cytotoxic activity of methyl jasmonate (MJ) in endometrial cancer cells and examined the hypothesis that the apoptotic and anti-proliferative actions of MJ in these cell lines can be enhanced by co-targeting the insulin-like growth factor-1 receptor (IGF1R) signaling pathway. MJ had a potent pro-apoptotic effect and exhibited significant toxicity in all cell lines tested. MJ in combination with NVP-AEW541, a selective IGF1R tyrosine kinase inhibitor, had significantly increased cytotoxicity. MJ decreased IGF1R phosphorylation, however, it enhanced AKT phosphorylation and abolished the anti-apoptotic effect of IGF1. These findings suggest that combined IGF1R inhibitor and MJ administration may constitute an attractive modality for treating endometrial cancer.