Phosphatidylinositol 3-kinase (PI3K) inhibitors as cancer therapeutics

Phosphatidylinositol 3-kinases (PI3Ks) are lipid kinases that regulate diverse cellular processes including proliferation, adhesion, survival, and motility. Dysregulated PI3K pathway signaling occurs in one-third of human tumors. Aberrantly activated PI3K signaling also confers sensitivity and resistance to conventional therapies. PI3K has been recognized as an attractive molecular target for novel anti-cancer molecules. In the last few years, several classes of potent and selective small molecule PI3K inhibitors have been developed, and at least fifteen compounds have progressed into clinical trials as new anticancer drugs. Among these, idelalisib has advanced to phase III trials in patients with advanced indolent non-Hodgkin's lymphoma and mantle cell lymphoma. In this review, we summarized the major molecules of PI3K signaling pathway, and discussed the preclinical models and clinical trials of potent small-molecule PI3K inhibitors.

Oral multikinase inhibitor regorafenib for the treatment of patients with metastatic colorectal cancer

SUMMARY Regorafenib is an oral small molecule inhibitor of multiple kinases involved in pathogenic processes, such as oncogenesis, tumor angiogenesis and maintenance of the tumor microenvironment, whose efficacy has been recently demonstrated in the treatment of pretreated metastatic colorectal cancer patients. The introduction of regorafenib into clinical practice allows medical oncologists to offer a new line of therapy to patients who have already received all of the other available drugs. Nevertheless, some issues deserve to be further examined in order to improve our knowledge of this drug’s potentialities and to better integrate its use in the daily routine, including the evaluation of response beyond convential size-based response evaluation criteria in solid tumors, the identification of molecular predictors of benefit, and the investigation of the potential role of regorafenib in different settings and in combination with other agents.

Signaling pathways in lymphoma: pathogenesis and therapeutic targets

Lymphoma is the fifth most common cancer in the USA. Most lymphomas are classified as non-Hodgkin’s lymphoma, and nearly 95% of these cancers are of B-cell origin. B-cell receptor (BCR) surface expression and BCR functional signaling are critical for survival and proliferation of both healthy B cells, as well as most B-lymphoma cells. Agents that inhibit various components of the BCR signaling pathway, as well as parallel signaling pathways, are currently in clinical trials for the treatment of various lymphoma subtypes, including those targeting isoforms of PI3K, mTOR and BTK. In this review, we describe the signaling pathways in healthy mature B cells, the aberrant signaling in lymphomatous B cells and the rationale for clinical trials of agents targeting these pathways as well as the results of clinical trials to date. We propose that the entry into a kinase inhibitor era of lymphoma therapy will be as transformative for our patients as the advent of the antibody or chemotherapy era before it.