echinomycin

We revealed that the HIF1A inhibitors echinomycin (EC) and YC-1 upregulated CXCL10/11 genes induced by IFN-γ in tumor cells in vitro...Combination therapy enhanced tumor infiltration of CD8 T cells and suppressed tumor angiogenesis. The present study suggests that HIF1A signaling in tumor cells dominates ICI resistance via the downregulation of tumor-derived CXCL10/11.

However, despite the massive increase in the number of marine natural products classified as 'anticancer leads,' most of which correspond to general cytotoxic agents, and only a few have been characterized regarding their molecular targets and mechanisms of action. The current review presents a critical analysis of inhibitors of HIF-1 and HIF-2 and hypoxia-selective compounds that have been sourced from marine organisms and that might act as new chemotherapeutic candidates or serve as templates for the development of structurally similar derivatives with improved anticancer efficacy.

Analogue 3 exhibited superior in vivo efficacy to echinomycin without significant toxicity in mouse xenograft model. The low dose of 3 needed to be efficacious in vivo is also noteworthy and our data suggest that 3 is an attractive and potentially novel agent for the treatment of colon cancer.

For that purpose, we assessed cellular viability/morphology after exposure to different concentrations of atorvastatin, with or without chemically induced hypoxia with chloride cobalt (CoCl) and with or without echinomycin (HIF-1α inhibitor). Our results supported the cytotoxic effects of atorvastatin. Additionally, we also revealed that besides these effects, under hypoxia, this drug induced proliferation of the neuroblastoma cells, supporting the importance of different stimuli and environment on the effect of drugs on cancer cells.

We further accessed the clinical potential of the two-drug combination approach with a xenograft mouse model of a colorectal MMR-deficient cancer, which has resulted in a significant synergistic anti-tumour effect. The current study provides a novel approach for the development of combination chemotherapy for the treatment of cancers related to DNA-mismatches.

Our comparative transcriptomic analysis has identified a bunch of new Echinomycin-regulated, Myc- and HIF1α-related genes contributed to KSHV pathogenesis, including KDM4B and Tau, which are required for the survival of KSHV + tumor cells with functional validation. These data together reveal that dual targeting Myc and HIF1α such as using Echinomycin may represent a new and promising option for treatments of these virus-associated malignancies.

In the immunocompetent HCC mouse model, depletion of pDCs using the antibody or HIF-1α inhibitor echinomycin significantly suppressed tumor growth...Reduced basic helix-loop-helix transcription factor E2-2 expression by treatments abrogated protumor functions of pDCs in HCC resulting in reactivating tumor-reactive CD8 T cells. This study demonstrates that targeting both pDCs and HIF-1α may serve as more effective immunotherapy for HCC.

The intracellular concentrations of doxorubicin in the two- and three-dimensional-SNP cells were 0.330 ± 0.013 and 0.290 ± 0.048 nM/mg protein, respectively. The three-dimensional-SNP cells treated with echinomycin showed weak LOX-1 fluorescence. The present study showed a clear difference in microRNA expression levels in cells cultured in a two-dimensional adherent versus a three-dimensional spheroid model.

The selective HIF-1 inhibitors echinomycin and PX-478 show antitumor effects against uterine fibroids both in vitro and in vivo. These findings support the potential use of HIF-1 inhibitors for the treatment of uterine fibroids.

The inhibition of HIF1-α could down-regulates the expression of WTAP, while the up-regulation of HIF1α could up-regulates the expression of WTAP, which shows that there is a positive correlation of HIF1α and WTAP expression. This result suggesting that HIF1α may be involves in the expression regulation of WTAP gene.

Furthermore, we showed that echinomycin treatment could effectively suppress oncogenic RAS-driven leukemia cell proliferation using both human leukemia cell lines and a mouse xenograft model. These data suggest that inhibiting the hypoxia pathway could be an effective treatment approach for oncogenic RAS-induced cancer phenotype, and that echinomycin is a promising targeted drug to attenuate oncogenic RAS-induced cancer phenotypes.

HIF-1α inhibition by echinomycin or small interfering RNA silencing prevented the hypoxia-mediated inhibition of mTORC1 and induction of IGFBP-1 secretion/phosphorylation...We propose that maternal undernutrition limits fetal oxygen delivery, as demonstrated by increased fetal liver expression of hypoxia-responsive proteins in baboon MNR. These findings have important implications for our understanding of the pathophysiology of restricted fetal growth.

HIF1α orchestrates expression of PDGF-D and PDGFRα for constitutive activation of AKT pathway and is crucial for GBM malignancy. Therefore, therapies targeting HIF1α should provide an effective treatment for GBM.

These results help to reveal the potential regulatory mechanisms of hypoxia-induced miR-210-3p expression that affect malignant behaviors and chemoresistance via TGF-β upregulation in glioma cells.

Pharmacologic targeting of HIF-1α by echinomycin delivered via nanoliposomes can efficiently restrain growth and metastasis of patient-derived relapsed anaplastic WiT xenografts. Liposomal echinomycin is more potent and effective in inhibiting WiT growth than vincristine in an anaplastic WiT mouse model, and eliminates metastasis by suppressing HIF-1α targets and the HIF-1α-IGFBP2 axis, which governs IGF1-AKT signaling.

Our data demonstrated a new mechanism by which echinomycin simultaneously targets MYC and HIF1α for degradation to inhibit growth of lung cancer and lymphoma. Given the broad impact of β-TrCP or VHL in stability of oncogenic proteins, echinomycin may emerge as a non-PROTAC (proteolysis targeting chimera) degrader of oncogenic proteins.

Furthermore, we observed the downregulation of BNIP3 and the decrease in autophagy after treatment with a specific HIF-1α activity inhibitor (echinomycin), indicating that HIF-1α/BNIP3 was involved in autophagy regulation in GCs in vivo...Expectedly, this effect could be reversed by 3-methyladenine (3-MA) treatment. Taken together, these findings demonstrated that hypoxia drives the activation of HIF-1α/BNIP3 signaling, which induces an increase in autophagy, protecting GC from apoptosis during follicular development.

Echinomycin was broadly effective against xenografts from multiple AML samples in vivo, and more effective than cytarabine + daunorubicin chemotherapy. Using TP53-mutated AML cell line THP1 and patient-derived AML cells, we tested a new echinomycin formulation with longer half-life and significantly improved therapeutic effect. Our data suggest a novel approach to treat AML with TP53 mutations.

Our findings indicate that TS-PDT may induce HO-1 expression via reactive oxygen species production and then HIF-1 pathway activation in KMY-J cells, and the HO-1 induction may cause attenuation of the therapeutic effect of TS-PDT.

Actively targeted nanodelivered echinomycin resulted in significant survival increases compared to Gemzar (S2VP10 p = 0.0003, S2CP9 p = 0.0017) or echinomycin only (S2VP10 p = 0.0096, S2CP9 p = 0.0073). We demonstrate that actively targeted nanodelivery of echinomycin results in autophagic cell death in pancreatic and potentially other high-autophagy, apoptosis-resistant tumors. Collectively, these findings support syndecan-1-targeted delivery of echinomycin and dysregulation of autophagy to induce cell death in pancreatic cancer.

Pharmacodynamic analyses reveal liposomal-echinomycin more potently inhibits HIF-1α transcriptional activity in primary and metastasized TNBC cells in vivo, the latter of which are HIF-1α enriched. The data suggests that nanoliposomal-echinomycin can provide safe and effective therapeutic HIF-1α inhibition and could represent the most potent HIF-1α inhibitor in prospective trials for metastatic cancer.

CHOP chemotherapy promotes glycolysis and IL-17 pathways in a HIF-1α-dependent fashion. Furthermore, HIF-1α blockade is promising as an accompanying agent in systemic chemotherapy for patients with advanced CTCL.