Current Drug Targets (v.16, #2)

Meet the Editorial Board: by Manuel S. Yepes (93-93).

Editorial (Mini-Thematic Issue: Morphological and Molecular Backgrounds for Personalized Therapies in Genitourinary Cancers) by Rodolfo Montironi, Marina Scarpelli, Matteo Santoni, Antonio Lopez-Beltran, Liang Cheng (94-95).

Morphologic and Molecular Backgrounds for Personalized Management of Genito-Urinary Cancers: An Overview by Rodolfo Montironi, Matteo Santoni, Antonio Lopez-Beltran, Liang Cheng, Holger Moch, Marina Scarpelli (96-102).
This contribution gives an overview of recent insights and emerging strategies for individualized therapeutic approaches based on genomic and cancer molecular profiles in patients with a morphological diagnosis of renal, bladder and prostate tumors. Significant advances have been made in molecular biology technologies, such as next-generation sequencing and whole-exome sequencing. The rise of such novel techniques has increased our knowledge on tumor cell biology and cancer development, thus allowing us to identify complex genomic abnormalities. These findings have paved the way to provide healthcare from an individual perspective. An emerging strategy to individualize therapeutic interventions is focused on stem cells. Because of their unique characteristics, they are among the most promising candidates as potential vectors carrying suicide genes into different types of cancer, including genitourinary tumors. Another emerging strategy could be based on prostate specific membrane antigen (PSMA), a unique membrane-bound glycoprotein, which is overexpressed manifold in prostate cancer. PSMA can serve as target for delivering therapeutic agents such as cytotoxins or radionuclides.

Molecular Foundations for Personalized Therapy in Prostate Cancer by Kurt W. Fisher, Rodolfo Montironi, Antonio Lopez Beltran, Holger Moch, Lisha Wang, Marina Scarpelli, Sean R. Williamson, Michael O. Koch, Liang Cheng (103-114).
Prostate cancer is the most common and second most lethal cancer in men. The majority of prostate cancers are histologically similar to acinar adenocarcinomas and rely on androgen-dependent signaling for their development and progression. Androgen deprivation therapy is a mainstay of treatment regimens and we discuss the recent advancements in androgen-deprivation therapy. Recent advances in defining the genetic landscape of prostate cancer have shown that the depth of genetic heterogeneity surpasses what can be seen histologically and has the ability to redefine treatments. TMPRSS2-ETS family fusion proteins are unique to prostate cancer and we discuss their role in carcinogenesis, prognosis, and the development of TMPRSS2-ETS family gene fusion targeted therapy. Inactivation of the tumor suppressor PTEN leads to activation of the PI3K/Akt/mTOR pathway and we discuss the prognostic and treatment implications. Molecular genetic analysis has recently demonstrated that clinically aggressive high grade neuroendocrine prostate carcinomas contain a high prevalence of overexpression of Aurora A kinase and N-myc. We discuss the role of Aurora A kinase and N-myc in the development of the aggressive neuroendocrine phenotype and the development of targeted inhibitors of this specific genetic subtype. Lastly, we briefly discuss emerging genetic subtypes defined by either SPINK1 overexpression, CHD1 inactivation, or SPOP mutations. By reviewing the associations between the morphologic features and the molecular genetics of prostate cancer we hope to provide insight and guidance to the emerging options for targeted therapy.

Bladder Cancer: Molecular Determinants of Personalized Therapy by Antonio Lopez-Beltran, Matteo Santoni, Francesco Massari, Chiara Ciccarese, Giampaolo Tortora, Liang Cheng, Holger Moch, Marina Scarpelli, Carlos Reymundo, Rodolfo Montironi (115-124).
Several molecular and genetic studies have provided new perspectives on the histologic classification of bladder tumors. Recent developments in the field of molecular mutational pathway analyses based on next generation sequencing technology together with classic data derived from the description of mutations in the FGFR3 (fibroblast growth factor receptor 3) gene, mutations on TP53 gene, and cDNA technology profiling data gives support to a differentiated taxonomy of bladder cancer. All these changes are behind the use of non-traditional approach to therapy of bladder cancer patients and are ready to change our daily practice of uro-oncology. The observed correlation of some molecular alterations with tumor behavior and the identification of their targets at cellular level might support the use of molecular changes together with morphological data to develop new clinical and biological strategies to manage patients with urothelial cancer. The current review provides comprehensive data to support personalized therapy for bladder cancer based on an integrated approach including pathologic and clinical features and molecular biology.

Oncotargets in Different Renal Cancer Subtypes by Holger Moch, Rodolfo Montironi, Antonio Lopez-Beltran, Liang Cheng, Axel Mischo (125-135).
Renal cell cancer is a heterogeneous group of cancers with different histologic subtypes. The majority of renal tumors in adults are clear cell renal cell carcinomas, which are characterized by von Hippel- Lindau (VHL) gene alterations. Recent advances in defining the genetic landscape of renal cancer has shown the genetic heterogeneity of clear cell renal cell carcinomas (ccRCC) and the presence of at least 3 additional ccRCC tumor suppressor genes on chromosome 3p. Due to inactivation of VHL, renal cancer cells produce the HIF-responsive growth factor VEGF. The PI3K--mTORC1 signaling axis also represents a target for therapy. The new systemic therapies, including tyrosine kinase inhibitors, monoclonal antibodies, and mTOR inhibitors, aim to suppress angiogenesis with vascular endothelial growth factor as a target [1]. Various VEGF-inhibitors are approved for the treatment of ccRCC and we discuss recent advancements in the treatment of metastatic ccRCC. Other gene alterations have been identified in hereditary cancer syndromes, e.g. FLCN, TSC1, TSC2, TFE3, TFEB, MITF, FH, SDHB, SDHD, MET, and PTEN and we review their role in renal tumor carcinogenesis, prognosis, and targeted therapy. By reviewing the associations between morphologic features and molecular genetics of renal cancer we provide insight into the basis for targeted renal cancer therapy.

Drug Nanocrystals: Four Basic Prerequisites for Formulation Development and Scale-Up by Kale Mohana Raghava Srivalli, Brahmeshwar Mishra (136-147).
Drug nanocrystals have been studied since the 1990s and there are already six therapeutic nanocrystal products on market and many more in clinical trials. Nanocrystals are encapsulating-carrier free nanoparticles wherein 100% drug loading could be achieved. This signifies that nanocrystals, among other nanoparticulate products, could be more easily manufactured even at the initial formulation development stages to evaluate the effect of size reduction on the bioavailability of drugs. Additionally, a drug nanocrystal is considered not as a generic product but as a “new drug” by FDA. Process characterization, equipment choice, robust formulation and stability are discussed as four basic prerequisites for formulation development and scale-up of drug nanocrystals. The fast growing and relatively superior market profile of nanocrystals amongst other nanoparticle systems is due to their rational formulation design and production simplicity. In this emerging scenario, keeping an eye on the four basic prerequisites can further improve the success of drug nanocrystals.

The APJ is a class A, rhodopsin-like G protein-coupled receptor (GPCR) with high sequence similarity to the angiotensin receptor AT1. APJ has been shown to be widely expressed in humans tissues, including the central nervous system, cardiovascular system, adipocytes and others. APJ plays an important role in the occurrence and development of cardiovascular and metabolic diseases including atherosclerosis (AS), coronary heart disease (CAD), heart failure(HF), pulmonary arterial hypertension (PAH), myocardial hypertrophy and atrial fibrillation, especially hypertension. Previous researchers found that apelin/APJ could induce vasodilation and then reduce blood pressure. Despite APJ is closely associated with many diseases, there are no drugs that can activate or inhibit APJ directly. In the current review, we have summarized recently reported peptides, small molecule agonists and antagonists targeting APJ. Given the role of apelin/APJ in hypertension and other cardiovascular diseases, we believe that the peptides and compounds based on APJ will be developed for treatment of these diseases.

ATP Citrate Lyase (ACLY): A Promising Target for Cancer Prevention and Treatment by Amrita Devi Khwairakpam, Mayengbam Singh Shyamananda, Bethsebie Lalduhsaki Sailo, Sivakumar Raju Rathnakaram, Ganesan Padmavathi, Jibon Kotoky, Ajaikumar B. Kunnumakkara (156-163).
ATP citrate lyase (ACLY), an important enzyme involved in lipid biogenesis linked with glucose metabolism, catalyzes the conversion of citrate to oxaloacetic acid (OAA) and acetyl-CoA. The obtained acetyl-CoA is required for lipid synthesis during membrane biogenesis, as well as for histone acetylation reactions to regulate the expression of certain proteins in aberrantly proliferating cancer cells. Studies have shown a role for ACLY in tumorigenesis whereby increased levels of the enzyme leads to increased metabolic activity via activation of Akt signaling. Increasing lines of evidence suggest that enzymes involved in lipid biogenesis play a significant role in cancer cell proliferation and progression. In many cancer types such as glioblastoma, colorectal cancer, breast cancer, non-small cell lung cancer, hepatocellular carcinoma etc., the level of ACLY has been found to be quite high as compared to normal cells. Cancer cell growth related to overexpression of ACLY can be inhibited by using chemical inhibitors or by the knockdown of ACLY gene. Inhibition of ACLY leads to changes in cancer cell metabolism that promotes tumor growth and proliferation. This review summarizes the role of ACLY in cancer development and its inhibitors in cancer treatment.

Inhibition of the VEGF/VEGFR Pathway Improves Survival in Advanced Kidney Cancer: A Systematic Review and Meta-Analysis by Roberto Iacovelli, Cora N. Sternberg, Camillo Porta, Elena Verzoni, Filippo de Braud, Bernard Escudier, Giuseppe Procopio (164-170).
Despite the improvement in progression-free survival and response rates, none of the five anti- VEGF/VEGFR agents used for treatment of metastatic renal cell carcinoma (mRCC) reported a significant increase in patients' survival. This analysis aims to investigate their effect on overall survival (OS), performing a meta-analysis of the available studies. MEDLINE/PubMed and the Cochrane Library were searched for randomised phase III trials that compared anti-VEGF/VEGFR agents with controls as upfront treatment for mRCC. The search was restricted to phase III trials, and data extraction was conducted according to the PRISMA statement. Five randomised phase III trials were included for a total of 3,469 patients; among these, 1,801 received anti-VEGF/VEGFR agents and 1,668 were treated with a placebo or interferon-?. In the overall population, the reduction in the risk of death was 13% (HR: 0.87; 95%CI, 0.80 - 0.95; p=0.002). When patients were divided based on use of VEGFR agents or an anti-VEGF monoclonal antibody, the reduction in the risk of death was 13% and 12%, respectively. If only treatmentnaïve patients are considered, we can confirm a significant reduction of 12% (HR=0.88; 95%CI, 0.79 - 0.97; p=0.010) in the risk of death. Our analysis reports a positive improvement of OS with the inhibition of the VEGF/VEGFR pathway in mRCC.

Anti-IgE Therapy with Omalizumab for Severe Asthma: Current Concepts and Potential Developments by Girolamo Pelaia, Alessandro Vatrella, Maria Teresa Busceti, Luca Gallelli, Rosa Terracciano, Rosario Maselli (171-178).
The humanized monoclonal anti-IgE antibody omalizumab is currently the only biologic drug approved for asthma treatment. Omalizumab inhibits allergic responses by binding to serum immunoglobulins E (IgE), thus preventing their interactions with cellular IgE receptors. Omalizumab is also capable of down-regulating the expression of high affinity IgE receptors on inflammatory cells, as well as the numbers of eosinophils in both peripheral blood and induced sputum. The clinical effects of omalizumab include relevant improvements in respiratory symptoms and quality of life, paralleled by a marked reduction of asthma exacerbations, emergency room visits, and use of systemic corticosteroids and rescue bronchodilators. Moreover, some recent studies suggest potential benefits of omalizumab also in non allergic phenotypes of severe asthma. Very interesting are also further recent reports referring to the potential inhibitory effect of omalizumab with regard to bronchial structural changes, especially occurring in severe asthma and globally defined as airway remodeling. Omalizumab is relatively well tolerated, and only very rarely induces anaphylactic reactions. Therefore, this drug represents a valid option as add-on therapy for patients with severe persistent asthma, inadequately controlled by high doses of standard inhaled treatments.