In Vivo and Clinical Studies of Natural Products Targeting the Hallmarks of Cancer

Despite more than 200 approved anticancer agents, cancer remains a leading cause of death worldwide due to disease complexity, tumour heterogeneity, drug toxicity, and the emergence of drug resistance. Accordingly, the development of chemotherapeutic agents with higher efficacy, a better safety profile, and the capability of bypassing drug resistance would be a cornerstone in cancer therapy. Natural products have played a pivotal role in the field of drug discovery, especially for the pharmacotherapy of cancer, infectious, and chronic diseases. Owing to their distinctive structures and multiple mechanistic activities, natural products and their derivatives have been utilized for decades in cancer treatment protocols. In this review, we delve into the potential of natural products as anticancer agents by targeting cancer's hallmarks, including sustained proliferative signalling, evading growth suppression, resisting apoptosis and cell death, enabling replicative immortality, inducing angiogenesis, and activating invasion and metastasis. We highlight the molecular mechanisms of some natural products, in vivo studies, and promising clinical trials. This review emphasizes the significance of natural products in fighting cancer and the need for further studies to uncover their fully therapeutic potential.

Anticancer Agents from Diverse Natural Sources

This review attempts to portray the discovery and development of anticancer agents/drugs from diverse natural sources. Natural molecules from these natural sources including plants, microbes and marine organisms have been the basis of treatment of human diseases since the ancient times. Compounds derived from nature have been important sources of new drugs and also serve as templates for synthetic modification. Many successful anti-cancer drugs currently in use are naturally derived or their analogues and many more are under clinical trials. This review aims to highlight the invaluable role that natural products have played, and continue to play, in the discovery of anticancer agents.

Targeting VEGF in lung cancer

INTRODUCTION

VEGF promotes tumor angiogenesis and is an important target in various malignancies, including NSCLC.

AREAS COVERED

Here, the authors review the data that led to the approval of bevacizumab, a monoclonal antibody against VEGF, in the treatment of lung cancer. The authors also review the key results from a number of Phase II and Phase III trials involving other anti-angiogenic agents being studied in NSCLC, including small-molecule tyrosine kinase inhibitors against the VEGF-receptor and vascular-disrupting agents (VDAs).

EXPERT OPINION

Results from ongoing studies and the identification of reliable biomarkers remain critical goals in understanding the exact role of these anti-angiogenic agents in the treatment paradigm of NSCLC.

Vascular effects of plinabulin (NPI-2358) and the influence on tumour response when given alone or combined with radiation

PURPOSE

This study investigated the anti-tumour effects of the novel vascular disrupting agent plinabulin (NPI-2358) when given alone or combined with radiation.

MATERIALS AND METHODS

Foot implanted C3H mammary carcinomas or leg implanted KHT sarcomas were used, with plinabulin injected intraperitoneally. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) measurements were made with gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) on a 7-tesla magnet. Treatment response was assessed using regrowth delay (C3H tumours), clonogenic survival (KHT sarcomas) or histological estimates of necrosis for both models.

RESULTS

Plinabulin (7.5 mg/kg) significantly reduced the initial area under curve (IAUC) and the transfer constant (K(trans)) within 1 hour after injection, reaching a nadir at 3 h, but returning to normal within 24 h. A dose-dependent decrease in IAUC and K(trans), was seen at 3 h. No significant anti-tumour effects were observed in the C3H tumours until doses of 12.5 mg/kg were achieved, but started at 1.5 mg/kg in the KHT sarcoma. Irradiating tumours 1 h after injecting plinabulin enhanced response in both models.

CONCLUSIONS

Plinabulin induced a time- and dose-dependent decrease in tumour perfusion. The KHT sarcoma was more sensitive than the C3H tumour to the anti-tumour effects of plinabulin, while radiation response was enhanced in both models.