Sugars, primarily glucose and fructose, are the main energy source of cells. Because of their hydrophilic nature, cells use a number of transporter proteins to introduce sugars through their plasma membrane. Cancer cells are well known to display an enhanced sugar uptake and consumption. In fact, sugar transporters are deregulated in cancer cells so they incorporate higher amounts of sugar than normal cells. In this paper, we compile the most significant data available about biochemical and biological properties of sugar transporters in normal tissues and we review the available information about sugar carrier expression in different types of cancer. Moreover, we describe the possible pharmacological interactions between drugs currently used in anticancer therapy and the expression or function of facilitative sugar transporters. Finally, we also go into the insights about the future design of drugs targeted against sugar utilization in cancer cells.

Eli Lilly and Company.

In recent years, it has been proposed that tumours are not homogeneous but composed of several cellular types like normal tissues. A cellular subtype, which is though to be the origin of tumours as well as their malignant properties (i.e., capacity for regrowth and metastasis), are the cancer stem cells (CSCs). CSCs, like normal stem cells, have a nearly unlimited capacity to self-renew and to proliferate so that are responsible, besides their same auto-perpetuation giving rise to the features previously depicted, also for the generation of the bulk of more differentiated cells in tumour. The altered behaviour of CSCs may be caused by the malfunction of a number of signalling pathways involved in normal embryonic development and in tissue homeostasis in adulthood. Among these signalling pathways are Wnt, Hedgehog, Notch and BMP pathways. In this review, we will focus on the study of molecular aspects of BMP signalling as well as its involvement in cancer.

Sunitinib is an orally available small-molecule multikinase inhibitor. This agent potently inhibits the vascular endothelial growth factor receptor, platelet-derived growth factor receptor, and c-Kit in addition to other kinases in biochemical and cell-based assays. In several relevant preclinical cancer models, sunitinib exerts significant antiangiogenesis and antitumor effects. In phase I studies, using intermittent dosing schedules, oral administration of doses up to 50 mg/day were reasonably well tolerated and resulted in plasma concentrations in the range of targeted levels needed for sustained kinase inhibition. Biomarker and functional imaging studies showed modulation of circulating markers of angiogenesis as well as a reduction in tumor metabolism. Sunitinib showed clinical activity in patients with renal cell cancer and in patients with imatinib-resistant gastrointestinal stromal tumors. Definitive randomized clinical trials showed significant clinical activity in these two indications leading to regulatory approval. In addition, this drug has showed activity in a variety of other tumor types such as breast, colon, and lung cancer and is being explored in combination with standard drugs in these diseases. The observation that biological and functional imaging effects are reduced during drug-free intervals has prompted the evaluation of protracted dosing schedules. A better understanding of mechanisms involved in resistance to sunitinib provides the rationale for combination strategies that hopefully will result in better clinical effect. Ongoing studies will elucidate the overall role of this drug in cancer treatment.