In vivo activity on murine tumors of a novel antitumor compound,N-β-dimethylaminoethyl 9-carboxy-5-hydroxy-10-methoxybenzo[a]phenazine-6-carboxamide sodium salt (NC-190)

Summary A novel antitumor compound, N--dimethylaminoethyl 9-carboxy-5-hydroxy-10-methoxybenzo[a]-phenazine-6-carboxamide sodium salt (NC-190) was evaluated for its antitumor activity in experimental murine tumor systems. In the initial studies with P388 leukemia (i.p.-i.p.), NC-190 led to an increase of >200% in life span (ILS), and 75% of the mice were alive on day 30, when the optimal dose (50 mg/kg, days 1–5) was given. Additionally, the compound had significant activities against i.p. inoculated mouse L1210 leukemia, B16 melanoma, M5076 reticulum cell sarcoma, sarcoma 180, mouse hepatoma MH134, and rat Yoshida sarcoma and Yoshida ascites hepatoma AH130. The optimal dose resulted in a >280% ILS with a 30-day survival of 50% in mice with L1210 leukemia (100 mg/kg, days 1–5), a 156% ILS in mice with B16 melanoma (50 mg/kg, days 1–5), a 98% ILS with a 90-day survival of 25% in mice with M5076 reticulum cell sarcoma (25 mg/kg, days 1, 5, 9, and 13), a >300% ILS with a 60-day survival of 50% in mice with sarcoma 180 (50 mg/kg, days 3–10), a 148% ILS with a 60-day survival of 25% in mice with MH134 (25 mg/kg, days 1–5), a 129% ILS with a 60-day survival of 12.5% in rats with Yoshida sarcoma (12.5 mg/kg, day 3–10), and a >161% ILS with a 60-day survival of 50% in rats with AH130 (6.3 mg/kg, days 3–10). In the experiments with s.c. inoculated tumors, NC-190 not only inhibited tumor growth, but also increased the life span of mice with Lewis lung carcinoma or B16 melanoma. The 60-day survivors accounted for 60% and 30% in mice with Lewis lung carcinoma and B16 melanoma, respectively. The compound significantly inhibited the spontaneous lung metastasis of Lewis lung carcinoma by more than 90% when eight daily i.v. injections were given. NC-190 was active by the i.p., s.c., and i.v. routes. Five consecutive daily i.p. doses (days 1–5) were more effective than a single dose (day 1), two doses (days 1 and 5), or three doses (days 1, 5, and 9). NC-190 warrants further study as a potential antineoplastic agent against human neoplasms, as it has a broad spectrum of antitumor activity and inhibits metastasis.Abbreviations ILS increase in life span - MST median survival time - MMC mitomycin C - ADM adriamycin - CPA cyclophosphamide - 5-FU 5-fluorouracil     

Exploiting the tumor microenvironment for theranostic imaging

The integration of chemistry and molecular biology with imaging is providing some of the most exciting opportunities in the treatment of cancer. The field of theranostic imaging, where diagnosis is combined with therapy, is particularly suitable for a disease as complex as cancer, especially now that genomic and proteomic profiling can provide an extensive 'fingerprint' of each tumor. Using this information, theranostic agents can be shaped for personalized treatment to target specific compartments, such as the tumor microenvironment (TME), whilst minimizing damage to normal tissue. These theranostic agents can also be used to target multiple pathways or networks by incorporating multiple small interfering RNAs (siRNAs) within a single agent. A decade ago genetic alterations were the primary focus in cancer research. Now it is apparent that the tumor physiological microenvironment, interactions between cancer cells and stromal cells, such as endothelial cells, fibroblasts and macrophages, the extracellular matrix (ECM), and a host of secreted factors and cytokines, influence progression to metastatic disease, aggressiveness and the response of the disease to treatment. In this review, we outline some of the characteristics of the TME, describe the theranostic agents currently available to target the TME and discuss the unique opportunities the TME provides for the design of novel theranostic agents for cancer therapy.     

Phospholipase D1 and choline kinase-α are interactive targets in breast cancer

A consistent metabolic hallmark observed in multiple cancers is the increase of cellular phosphocholine (PC) and total choline-containing compounds (tCho), which is closely related to malignant transformation, invasion, and metastasis. Enzymes in choline phospholipid metabolism present attractive targets to exploit for treatment, but require a clear understanding of the mechanisms underlying the altered choline phospholipid metabolism observed in cancer. Choline kinase-α (Chk-α) is an enzyme in the Kennedy pathway that phosphorylates free choline (Cho) to PC, and its upregulation in several cancers is a major contributor to increased PC levels. Similarly, increased expression and activity of phospholipase D1 (PLD1), which converts phosphatidylcholine (PtdCho) to phosphatidic acid (PA) and Cho, has been well documented in gastric, ovarian and breast cancer. Here we report a strong correlation between expression of Chk-α and PLD1 with breast cancer malignancy. Data from patient samples established an association between estrogen receptor (ER) status and Chk-α and PLD1 expression. In addition, these two enzymes were found to be interactive. Downregulation of Chk-α with siRNA increased PLD1 expression, and downregulation of PLD1 increased Chk-α expression. Simultaneous silencing of PLD1 and Chk-α in MDA-MB-231 cells increased apoptosis as detected by the TUNEL assay. These data provide new insights into choline phospholipid metabolism of breast cancer, and support multiple targeting of enzymes in choline phospholipid metabolism as a strategy for treatment.     

Vortioxetine: a novel antidepressant for the treatment of major depressive disorder

Introduction: Vortioxetine is a novel antidepressant drug approved for the treatment of major depressive disorder (MDD) in adults. It is formulated into tablets and has a dose range of 5–20 mg. The recommended starting dose is 10 mg administered orally once daily without the need for food.

Areas covered: This review focuses on the preclinical and clinical discovery of vortioxetine. It analyzes the pharmacological, neurochemical, and behavioral mechanisms of the medication and how these contribute to its potential therapeutic advantages as described in published preclinical and clinical studies and product labels.

Expert opinion: Vortioxetine displays high affinity for serotonin transporter (SERT), and serotonin 5-HT₃, 5HT_1A, 5HT₇ receptors. Functional studies show that vortioxetine acts as a SERT blocker, a 5-HT₃, 5-HT₇ receptor antagonist, and a 5-HT_1A receptor agonist. The drug is active in animal models predictive of antipsychotic and antidepressant activities and demonstrates procognitive effects in several animal models that assessed memory, cognition, and executive functions. Short- and long-term clinical trials demonstrated the clinical efficacy of vortioxetine in treating depressive symptoms and cognitive deficits in MDD patients. It also displays fairly benign safety and tolerability profiles. Vortioxetine’s unique psychopharmacological properties might contribute to an improved clinical outcome in MDD patient populations.     

Chemical removal of the endothelium by saponin in the isolated dog femoral artery

Chemical removal of the endothelium by saponin in the isolated dog femoral artery was investigated by comparing the relaxant responses to endothelium-dependent and -independent vasodilators of saponin-treated rings with the responses of non-treated rings. Saponin treatment was done by incubating rings with Krebs-Henseleit solution containing 0.1, 0.3 or 1 mg/ml of saponin for 45 min at 37 degrees C. In non-treated rings, acetylcholine (10(-8)-3 X 10(-6) M) caused a concentration-dependent relaxation of rings precontracted with prostaglandin F2 alpha (3 X 10(-6) M). The acetylcholine-induced relaxation was reduced in rings pretreated with 0.1 mg/ml of saponin and almost abolished with 0.3 or 1 mg/ml. Prostaglandin F2 alpha-induced contraction was suppressed weakly by treatment with 0.3 mg/ml and markedly with 1 mg/ml saponin. The treatment with 0.3 mg/ml saponin markedly reduced relaxations caused by substance P (10(-9)-3 X 10(-8) M) and by Ca2+-ionophore A23187 (10(-6) M). Relaxant responses of saponin-treated rings to nitroglycerin and to nitroprusside were almost identical with those of non-treated rings. These results showing selective suppression by saponin of the endothelium-dependent relaxation suggest that saponin removes the endothelial cells from the intimal surface of the artery, and this was confirmed by electron microscopy. The endothelium removing method with saponin seems to be useful as a pharmacological tool for vascular investigations.     

Choline kinase overexpression increases invasiveness and drug resistance of human breast cancer cells

A direct correlation exists between increased choline kinase (Chk) expression, and the resulting increase of phosphocholine levels, and histological tumor grade. To better understand the function of Chk and choline phospholipid metabolism in breast cancer we have stably overexpressed one of the two isoforms of Chk‐α known to be upregulated in malignant cells, in non‐invasive MCF‐7 human breast cancer cells. Dynamic tracking of cell invasion and cell metabolism were studied with a magnetic resonance (MR) compatible cell perfusion assay. The MR based invasion assay demonstrated that MCF‐7 cells overexpressing Chk‐α (MCF‐7‐Chk) exhibited an increase of invasion relative to control MCF‐7 cells (0.84 vs 0.3). Proton MR spectroscopy studies showed significantly higher phosphocholine and elevated triglyceride signals in Chk overexpressing clones compared to control cells. A test of drug resistance in MCF‐7‐Chk cells revealed that these cells had an increased resistance to 5‐fluorouracil and higher expression of thymidylate synthase compared to control MCF‐7 cells. To further characterize increased drug resistance in these cells, we performed rhodamine‐123 efflux studies to evaluate drug efflux pumps. MCF‐7‐Chk cells effluxed twice as much rhodamine‐123 compared to MCF‐7 cells. Chk‐α overexpression resulted in MCF‐7 human breast cancer cells acquiring an increasingly aggressive phenotype, supporting the role of Chk‐α in mediating invasion and drug resistance, and the use of phosphocholine as a biomarker of aggressive breast cancers. Copyright © 2010 John Wiley & Sons, Ltd.     

A novel low molecular weight VEGF receptor-binding antagonist, VGA1102, inhibits the function of VEGF and in vivo tumor growth

Vascular endothelial cell growth factor (VEGF) plays an important role in the processes of angiogenesis. Angiogenesis appears to be essential for the growth of solid tumors and their metastasis. VEGF plays a principal role in tumor angiogenesis. To identify a compound that inhibits the binding of VEGF to its receptor, we used a high-throughput screening method and found that oxydibenzoic acid derivatives inhibited VEGF binding to its receptors. Among the active compounds, 5-{3-[4-(octadecyloxy)phenyl]propionylamino}-2,4-oxydibenzoic acid (VGA1102) was selected based on its potent binding inhibitory activity. VGA1102 inhibited [¹²⁵I]VEGF binding to both of two VEGF receptor-transfected cell lines, NIH-Flt-1 and NIH-KDR/Flk-1, in a concentration-dependent manner, with IC₅₀ values of 0.66±0.07 and 0.61±0.16 M, respectively. VGA1102 (10 M) exhibited inhibitory activity against VEGF-induced receptor autophosphorylation. VGA1102 also inhibited VEGF-induced growth of rat liver sinusoidal endothelial cells (IC₅₀=0.89±0.16 M) as well as VEGF-induced tube formation of HUVEC in vitro. VGA1102 reduced intradermal VEGF-induced vascular permeability in guinea pigs. Treatment with VGA1102 (50 mg/kg, i.p., days 0–20) significantly increased the lifespan of MM2-bearing mice with an increase in lifespan of >195.8%, and all such mice were long-term survivors on day 71. Furthermore, VGA1102 (50 mg/kg, i.p.) administered daily suppressed the growth of nude mice transplanted with LC-6 human non-small-cell lung cancer. These results suggest that VGA1102 inhibits VEGF function resulting in inhibition of tumor angiogenesis, which led to suppression of growth of human tumors transplanted into nude mice.Abbreviations BSA bovine serum albumin - DMEM Dulbeccos modified Eagles medium - FBS fetal bovine serum - Flt-1 fms-like tyrosine kinase - HUVEC human umbilical vein endothelial cells - ILS increase in lifespan - KDR/Flk-1 kinase insert domain containing receptor/fetal liver kinase - MEM minimum essential medium - MST median survival time - MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide - PBS phosphate-buffered saline - VEGF vascular endothelial growth factor