Cytomodulin-1, a synthetic peptide abrogates oncogenic signaling pathways to impede invasion and angiogenesis in the hamster cheek pouch carcinogenesis model

Gramine inhibits angiogenesis and induces apoptosis via modulation of TGF-β signalling in 7,12 dimethylbenz[a]anthracene (DMBA) induced hamster buccal pouch carcinoma

BACKGROUND

Transforming growth factor-β (TGF-β) and its receptors are considered as a novel target in cancer chemotherapy. Gramine, an indole alkaloid, possesses various pharmacological properties including antiproliferative and anticancer. However, the anti-angiogenic property remains unexplored.

PURPOSE

The present study was designed to evaluate the anti-angiogenic and apoptosis induction properties of gramine through inhibiting TGF-β on DMBA induced oral squamous cell carcinoma (OSCC) in the hamster buccal pouch (HBP).

METHODS

The effects of gramine on TGF-β signalling in DMBA induced carcinogenic events such as angiogenesis and apoptosis were analysed by studying the mRNA expression using RT-PCR, protein expression by western blot and histopathological analysis using haematoxylin and eosin (H & E) staining.

RESULTS

Gramine significantly inhibited phosphorylation and nuclear translocation of Smad2 and Smad4 by blocking activity of the TGFβ-RII, RI and activation of inhibitory Smad7. Gramine inhibited angiogenic markers such as MMP-2, MMP-9, HIF-1α, VEGF, and VEGF-R2 as well as increased TIMP-2 expression. Furthermore, gramine induced apoptosis in DMBA induced tumour bearing animals by up regulating the pro apoptotic proteins Bax, cytochrome C, apaf-1, caspase-9 caspase-3 and PARP.

CONCLUSION

In this study, we clearly demonstrated that gramine treatment diminishes angiogenesis and induces apoptosis in hamster buccal pouch (HBP) carcinogenesis by modulating TGF-β signals.

The Hamster Buccal Pouch Model of Oral Carcinogenesis

The hamster buccal pouch (HBP) carcinogenesis model is one of the most well-characterized animal tumor models used as a prelude to investigate multistage oral carcinogenesis and to assess the efficacy of chemointervention. Hamster buccal pouch carcinomas induced by 7,12-dimethylbenz[a]anthracene (DMBA) show extensive similarities to human oral squamous cell carcinomas. The HBP model offers a number of advantages including a simple and predictable tumor induction procedure, easy accessibility for examination and follow-up of lesions, and reproducibility. This model can be used to test both chemopreventive and chemotherapeutic agents.

Gedunin abrogates aldose reductase, PI3K/Akt/mToR, and NF-κB signaling pathways to inhibit angiogenesis in a hamster model of oral carcinogenesis

Aberrant activation of oncogenic signaling pathways plays a central role in tumor development and progression. The aim of this present study was to investigate the chemopreventive effects of the neem limonoid gedunin in the hamster model of oral cancer based on its ability to modulate aldose reductase (AR), phosphatidyl inositol-3-kinase (PI3K)/Akt, and nuclear factor kappa B (NF-κB) pathways to block angiogenesis. Administration of gedunin suppressed the development of HBP carcinomas by inhibiting PI3K/Akt and NF-κB pathways through the inactivation of Akt and inhibitory kappa B kinase (IKK), respectively. Immunoblot and molecular docking interactions revealed that inhibition of these signaling pathways may be mediated via inactivation of AR by gedunin. Gedunin blocked angiogenesis by downregulating the expression of miR-21 and the pro-angiogenic factors vascular endothelial growth factor and hypoxia inducible factor-1 alpha (HIF-1α). In conclusion, the results of the present study provide compelling evidence that gedunin prevents progression of hamster buccal pouch (HBP) carcinomas via inhibition of the kinases Akt, IKK, and AR, and the oncogenic transcription factors NF-κB and HIF-1α to block angiogenesis.

Discovery of biphenyl-based VEGFR-2 inhibitors. Part 3: design, synthesis and 3D-QSAR studies

VEGFR-2 plays an essential role in angiogenesis and is a central target for anticancer drug discovery. In order to develop novel VEGFR-2 inhibitors, we designed and synthesized 33 biphenyl amides based on our previously reported lead compound. The biological results indicated that four compounds (18b, 20e, 20h and 20j) are potent VEGFR-2 inhibitors which are comparable to positive control. Compound 18b displayed the most potent VEGFR-2 inhibition with IC50 value of 2.02nM. Moreover, it exhibited promising antiproliferative activity against MCF-7 and SMMC-7721 cells with IC50 values of 1.47μM and 5.98μM, respectively. Molecular docking and 3D-QSAR studies were also carried out. The results indicated that these biphenyl amides could serve as promising leads for further optimization as novel VEGFR-2 inhibitors.