Targeting angiogenesis for treatment of human cancer

Outline of gelatinase inhibitors as anti-cancer agents: A patent mini-review for 2010-present

Matrix metalloproteinases (MMPs) are involved in several pathological and physiological functions. Gelatinases (MMP-2 and -9) have significant attention as therapeutic targets against cancer. Gelatinase inhibitors have demonstrated their effectiveness in several diseases including cancer. However, it is quite a challenging task to develop inhibitors as a therapeutic agent. This review summarizes the patent dedicated to the medicinal chemistry of gelatinase inhibitor reported over last decades. We examine the patent being pursued for gelatinase inhibitor development to highlight the key issues. The main aim is to provide the scientific community with an overview of the patented gelatinase inhibitors to allow further development. During early 2000s, some MMP inhibitors failed to pass the clinical trials. Hence, the lessons learned from early evidence and recent knowledge in that field will rejuvenate the development of selective inhibitors. Various studies and patents have continued in the recent years to expand knowledge. Continuously, our research team has been involved in the design of potent and selective gelatinase inhibitors for the past few years. This study is a part of our efforts. This study may be beneficial in the design and development of better gelatinase inhibitors in the future.

Targeting Strategies for the Combination Treatment of Cancer Using Drug Delivery Systems

Cancer cells have characteristics of acquired and intrinsic resistances to chemotherapy treatment-due to the hostile tumor microenvironment-that create a significant challenge for effective therapeutic regimens. Multidrug resistance, collateral toxicity to normal cells, and detrimental systemic side effects present significant obstacles, necessitating alternative and safer treatment strategies. Traditional administration of chemotherapeutics has demonstrated minimal success due to the non-specificity of action, uptake and rapid clearance by the immune system, and subsequent metabolic alteration and poor tumor penetration. Nanomedicine can provide a more effective approach to targeting cancer by focusing on the vascular, tissue, and cellular characteristics that are unique to solid tumors. Targeted methods of treatment using nanoparticles can decrease the likelihood of resistant clonal populations of cancerous cells. Dual encapsulation of chemotherapeutic drug allows simultaneous targeting of more than one characteristic of the tumor. Several first-generation, non-targeted nanomedicines have received clinical approval starting with Doxil® in 1995. However, more than two decades later, second-generation or targeted nanomedicines have yet to be approved for treatment despite promising results in pre-clinical studies. This review highlights recent studies using targeted nanoparticles for cancer treatment focusing on approaches that target either the tumor vasculature (referred to as 'vascular targeting'), the tumor microenvironment ('tissue targeting') or the individual cancer cells ('cellular targeting'). Recent studies combining these different targeting methods are also discussed in this review. Finally, this review summarizes some of the reasons for the lack of clinical success in the field of targeted nanomedicines.

Tanshinone IIA induces intrinsic apoptosis in osteosarcoma cells both in vivo and in vitro associated with mitochondrial dysfunction

Tanshinone IIA (Tan IIA), a phytochemical derived from the roots of Salvia miltiorrhiza, has been shown to inhibit growth and induce apoptosis in various cancer cells. The association of its inhibitory effect on the primary malignant bone tumor, osteosarcoma, with mitochondrial dysfunction remains unclear. This study aimed to investigate the anti-proliferative effects of Tan IIA on human osteosarcoma 143B cells both in vitro and in vivo. Administration of Tan IIA to NOD-SCID mice implanted with 143B cells led to significant inhibition of tumor development. The inhibition of proliferation, migration, and invasion was observed in 143B cells treated with Tan IIA. The tumor proliferation markers, Ki67 and PCNA, were suppressed and apoptosis by TUNEL assay was activated respectively. Apoptosis in the Tan IIA-treated 143B cells and xerograft mice was associated with the activation of caspase cascade via the modulation of Bcl-2 family. The CD31 was inhibited in Tan IIA-treated xenografts to indicate anti-neovasculization. Tan IIA administration resulted in a significant decrease in the mitochondrial fusion proteins, Mfn1/2 and Opa1, as well as an increase in the fission protein Drp1. We concluded that mitochondrial dysfunction associated with dynamic change was involved in apoptosis and anti-angiogenesis elicited by Tan IIA.

Pseudogene CYP4Z2P 3'UTR promotes angiogenesis in breast cancer

Pseudogenes have long been marked as "false" genes, which are similar with real genes but have no apparent function. The 3'UTR is well-known to regulate gene expression post-transcriptionally. Our recent evidence, however, indicates novel functional roles of pseudogene CYP4Z2P 3'UTR (Z2P-UTR). We found that ectopic expression of Z2P-UTR in breast cancer cells significantly increased the expression of VEGF-A without affecting cell proliferation in vitro. Meanwhile, conditioned medium (CM) from Z2P-UTR overexpression cells enhanced proliferation, migration and tube formation of HUVEC, and promoted angiogenesis in ex vivo models. Also, CM increased the expression of VEGFR2 in HUVEC. Our data suggest that Z2P-UTR can promote breast cancer angiogenesis partly via paracrine pathway of VEGF-A/VEGFR2.

Effects of honey and its mechanisms of action on the development and progression of cancer

Honey is a natural product known for its varied biological or pharmacological activities-ranging from anti-inflammatory, antioxidant, antibacterial, antihypertensive to hypoglycemic effects. This review article focuses on the role of honey in modulating the development and progression of tumors or cancers. It reviews available evidence (some of which is very recent) with regards to the antimetastatic, antiproliferative and anticancer effects of honey in various forms of cancer. These effects of honey have been thoroughly investigated in certain cancers such as breast, liver and colorectal cancer cell lines. In contrast, limited but promising data are available for other forms of cancers including prostate, bladder, endometrial, kidney, skin, cervical, oral and bone cancer cells. The article also underscores the various possible mechanisms by which honey may inhibit growth and proliferation of tumors or cancers. These include regulation of cell cycle, activation of mitochondrial pathway, induction of mitochondrial outer membrane permeabilization, induction of apoptosis, modulation of oxidative stress, amelioration of inflammation, modulation of insulin signaling and inhibition of angiogenesis. Honey is highly cytotoxic against tumor or cancer cells while it is non-cytotoxic to normal cells. The data indicate that honey can inhibit carcinogenesis by modulating the molecular processes of initiation, promotion, and progression stages. Thus, it may serve as a potential and promising anticancer agent which warrants further experimental and clinical studies.