20th-century advances in drug therapy in oncology--Part I

Tumor-Associated Neutrophils in Cancer: Going Pro

The progression of cancer is not only about the tumor cell itself, but also about other involved players including cancer cell recruited immune cells, their released pro-inflammatory factors, and the extracellular matrix. These players constitute the tumor microenvironment and play vital roles in the cancer progression. Neutrophils—the most abundant white blood cells in the circulation system—constitute a significant part of the tumor microenvironment. Neutrophils play major roles linking inflammation and cancer and are actively involved in progression and metastasis. Additionally, recent data suggest that neutrophils could be considered one of the emerging targets for multiple cancer types. This review summarizes the most recent updates regarding neutrophil recruitments and functions in the tumor microenvironment as well as potential development of neutrophils-targeted putative therapeutic strategies.

Magnetic property, DFT calculation, and biological activity of bis[(μ(2)-chloro)chloro(1,10-phenanthroline)copper(II)] complex

The dinuclear complex bis[(μ(2)-chloro)chloro(1,10-phenanthroline)copper(II)] (1) was synthesized, and characterized by X-ray, FTIR and thermal analysis. The fitting of magnetic susceptibility and magnetization curve of (1) indicates the occurrence of weak antiferromagnetic exchange interaction between copper(II) ions. The electronic structure has been also determined by density functional theory (DFT) method. Complex (1) displayed potent anticancer activity against B16 (Melanoma), MDA-MB-32 (Breast Adenocarcinoma), A549 (Lung Adenocarcinoma), HT-29 (Colon Adenocarcinoma) and SF (Astrocytoma) cell lines with an average IC50 value of 0.726 μg/ml compared to 4.88 μg/ml for cisplatin. Complex (1) has a better therapeutic index and toxicological profile than cisplatin, and has demonstrated a potential chemotherapeutic property.

Lysosomotropic properties of weakly basic anticancer agents promote cancer cell selectivity in vitro

Drug distribution in cells is a fundamentally important, yet often overlooked, variable in drug efficacy. Many weakly basic anticancer agents accumulate extensively in the acidic lysosomes of normal cells through ion trapping. Lysosomal trapping reduces the activity of anticancer drugs, since anticancer drug targets are often localized in the cell cytosol or nucleus. Some cancer cells have defective acidification of lysosomes, which causes a redistribution of trapped drugs from the lysosomes to the cytosol. We have previously established that such differences in drug localization between normal and cancer cells can contribute to the apparent selectivity of weakly basic drugs to cancer cells in vitro. In this work, we tested whether this intracellular distribution-based drug selectivity could be optimized based on the acid dissociation constant (pKa) of the drug, which is one of the determinants of lysosomal sequestration capacity. We synthesized seven weakly basic structural analogs of the Hsp90 inhibitor geldanamycin (GDA) with pKa values ranging from 5 to 12. The selectivity of each analog was expressed by taking ratios of anti-proliferative IC₅₀ values of the inhibitors in normal fibroblasts to the IC₅₀ values in human leukemic HL-60 cells. Similar selectivity assessments were performed in a pair of cancer cell lines that differed in lysosomal pH as a result of siRNA-mediated alteration of vacuolar proton ATPase subunit expression. Optimal selectivity was observed for analogs with pKa values near 8. Similar trends were observed with commercial anticancer agents with varying weakly basic pKa values. These evaluations advance our understanding of how weakly basic properties can be optimized to achieve maximum anticancer drug selectivity towards cancer cells with defective lysosomal acidification in vitro. Additional in vivo studies are needed to examine the utility of this approach for enhancing selectivity.

Evaluation of human LOX-12 as a serum marker for breast cancer

The high concentration of prostaglandins has been associated with chronic inflammatory diseases and several types of human cancers. This is due to the over expression of inflammatory enzymes like Cyclooxygenase (COX), Lipoxygenase (LOX) etc. The aim of this study was to quantify the LOX-12 with clinicopathological parameter of breast cancer patients and its response after chemotherapy to establish serum LOX-12 as a prognostic marker. This case-controlled study was performed on 86 biopsy proven breast cancer patients. Blood and tissue samples were collected from the patients. Serum LOX-12 of the study group was quantified by Surface Plasmon Resonance (SPR) and ELISA techniques by antibody-antigen interaction strategy. A significant increase in LOX-12 levels was observed in breast cancer patients (Mean ± SD=40.54±13.61 ng/ml) as compared to healthy controls (Mean ± SD=13.42±2.4 ng/ml) (p<0.0001). Serum LOX-12 levels were significantly higher (p<0.002) in patients with lymph node involvement. More than 75% patients had shown significant (p<0.0001) reduction of LOX-12 levels after chemotherapy. This was also confirmed by ELISA. This study for the first time had co-related the quantity of serum LOX-12 with breast cancer and also with the effect of chemotherapy.

Structure-activity relationships of carboline and carbazole derivatives as a novel class of ATP-competitive kinesin spindle protein inhibitors

The kinesin spindle protein (KSP) is a mitotic kinesin involved in the establishment of a functional bipolar mitotic spindle during cell division. It is considered to be an attractive target for cancer chemotherapy with reduced side effects. Based on natural product scaffold-derived fused indole-based inhibitors and known biphenyl-type KSP inhibitors, various carboline and carbazole derivatives were synthesized and biologically evaluated. β-Carboline and lactam-fused carbazole derivatives exhibited remarkably potent KSP inhibitory activity and mitotic arrest in prometaphase with formation of an irregular monopolar spindle. The planar tri- and tetracyclic analogs inhibited KSP ATPase in an ATP-competitive manner just like biphenyl-type inhibitors.

The role of lysosomes in limiting drug toxicity in mice

The distribution behavior of a drug within a cell is an important, yet often overlooked, variable in both activity and differential selectivity. In normal cells, drugs with weakly basic properties are known to be extensively compartmentalized in acidic organelles such as lysosomes via ion trapping. Several cancer cell lines have been shown to have defective acidification of endocytic organelles and therefore have a diminished capacity to sequester such lysosomotropic agents. In this study, we tested the hypothesis that the low lysosomal pH of normal cells plays an important role in protecting normal tissues from the toxic effects of lysosomotropic anticancer drugs. The influence of lysosomal pH status on the toxicity of inhibitors of the molecular chaperone Hsp90 that did or did not possess lysosomotropic properties was evaluated in mice. Toxicity of Hsp90 inhibitors was evaluated in normal mice and in mice treated with chloroquine to elevate lysosomal pH by assessing morbidity and utilizing biochemical assays to diagnose hepatic and renal toxicity. Toxicity of the lysosomotropic inhibitor 17-dimethylaminoethylamino-17-demethoxy-geldanamycin (17-DMAG) was significantly enhanced in mice with elevated lysosomal pH relative to mice with normal lysosomal pH. In contrast, elevation of lysosomal pH had no significant impact on toxicity of the nonlysosomotropic inhibitor geldanamycin. These results support the notion that the low lysosomal pH of normal cells plays an important role in protecting these cells from the toxic effects of anticancer agents with lysosomotropic properties and has implications for the design/selection of anticancer drugs with improved safety and differential selectivity.

Kinesin spindle protein (KSP) inhibitors. 9. Discovery of (2S)-4-(2,5-difluorophenyl)-n-[(3R,4S)-3-fluoro-1-methylpiperidin-4-yl]-2-(hydroxymethyl)-N-methyl-2-phenyl-2,5-dihydro-1H-pyrrole-1-carboxamide (MK-0731) for the treatment of taxane-refractory cancer

Inhibition of kinesin spindle protein (KSP) is a novel mechanism for treatment of cancer with the potential to overcome limitations associated with currently employed cytotoxic agents. Herein, we describe a C2-hydroxymethyl dihydropyrrole KSP inhibitor ( 11) that circumvents hERG channel binding and poor in vivo potency, issues that limited earlier compounds from our program. However, introduction of the C2-hydroxymethyl group caused 11 to be a substrate for cellular efflux by P-glycoprotein (Pgp). Utilizing knowledge garnered from previous KSP inhibitors, we found that beta-fluorination modulated the p K a of the piperidine nitrogen and reduced Pgp efflux, but the resulting compound ( 14) generated a toxic metabolite in vivo. Incorporation of fluorine in a strategic, metabolically benign position by synthesis of an N-methyl-3-fluoro-4-(aminomethyl)piperidine urea led to compound 30 that has an optimal in vitro and metabolic profile. Compound 30 (MK-0731) was recently studied in a phase I clinical trial in patients with taxane-refractory solid tumors.

Anti-microtubule activity of tubeimoside I and its colchicine binding site of tubulin

Background

Tubeimoside I (TBMS1) was isolated from the tubers of Bolbostemma paniculatum (Maxim.) Franquet. TBMS1 shows potent anti-tumor activity. The present study was conducted to investigate the anti-microtubule role of TBMS1 and its binding site of tubulin.

Methods

Cell growth inhibition was measured by MTT after treatment with TBMS1. Uptake kinetics of TBMS1 by human nasopharyngeal carcinoma CNE-2Z cell line (CNE-2Z) was assayed by HPLC. Microtubule protein (MTP) was prepared from porcine brain through two cycles of polymerization–depolymerization in a high molarity buffer. Inhibition of MTP polymerization induced by TBMS1 was determined by a turbidity measurement and a sedimentation assay; the interactions of TBMS1 with tubulin within CNE-2Z cells were investigated by immunofluorescence microscopy and immunoblotting. TBMS1 was tested for its ability to inhibit binding of known tubulin ligands through competitive binding assay.

Results

TBMS1 displayed growth inhibitory activity against CNE-2Z cells with IC₅₀ value of 16.7 μM for 72 h. HPLC analysis of TBMS1 uptake by CNE-2Z cells displayed the initial slow TBMS1 uptake and then gradually reaching an maximum uptake near 18 h. CNE-2Z cells treated with TBMS1 (25 μM, 3 h) were sufficient to cause the microtubular network disruption. Immunoblot analysis showed that the proportion of cytosolic tubulin of cells treated with TBMS1 increased in a time- and concentration-dependent manner. TBMS1 did not inhibit the binding of vinblastine to tubulin. Colchicine binding to tubulin was inhibited in the presence of TBMS1.

Conclusions

TBMS1 is an anti-microtubule agent, and its binding site of tubulin is the colchicine binding site of tubulin.

Synthesis and biological evaluation of L-cysteine derivatives as mitotic kinesin Eg5 inhibitors

Inhibition of Eg5 represents a novel approach for the treatment of cancer. Here, we report the synthesis and structure-activity relationship of S-trityl-L-cysteine (STLC) derivatives as Eg5 inhibitors. Some of these derivatives such as 4f demonstrated enhanced inhibitory activity against Eg5 and induced mitotic arrest with characteristic monoastral spindles in HeLa cells.

Kinesin spindle protein (KSP) inhibitors. Part V: Discovery of 2-propylamino-2,4-diaryl-2,5-dihydropyrroles as potent, water-soluble KSP inhibitors, and modulation of their basicity by β-fluorination to overcome cellular efflux by P-glycoprotein

Installation of a C2-aminopropyl side chain to the 2,4-diaryl-2,5-dihydropyrrole series of kinesin spindle protein (KSP) inhibitors results in potent, water soluble compounds, but the aminopropyl group induces susceptibility to cellular efflux by P-glycoprotein (Pgp). We show that by carefully modulating the basicity of the amino group by beta-fluorination, this series of inhibitors maintains potency against KSP and has greatly improved efficacy in a Pgp-overexpressing cell line. The discovery that cellular efflux by Pgp can be overcome by carefully modulating the basicity of an amine may be of general use to medicinal chemists attempting to transform leading compounds into cancer cell- or CNS-penetrant drugs.

Synthesis and SAR of thiophene containing kinesin spindle protein (KSP) inhibitors

We have identified and synthesized a series of thiophene containing inhibitors of kinesin spindle protein. SAR studies led to the synthesis of 33, which was co-crystallized with KSP and determined to bind to an allosteric pocket previously described for other known KSP inhibitors.

Synthesis and SAR of pyrrolotriazine-4-one based Eg5 inhibitors

Synthesis and SAR of substituted pyrrolotriazine-4-one analogues as Eg5 inhibitors are described. Many of these analogues displayed potent inhibitory activities in the Eg5 ATPase and A2780 cell proliferation assays. In addition, pyrrolotriazine-4-one analogue 26 demonstrated in vivo efficacy in an iv P388 murine leukemia model. Both NMR and X-ray crystallographic studies revealed that these analogues bind to an allosteric site on the Eg5 protein.

Inhibitors of human mitotic kinesin Eg5: Characterization of the 4-phenyl-tetrahydroisoquinoline lead series

In a high-throughput screening effort, a series of tetrahydroisoquinolines was identified as modest inhibitors of human Eg5. A medicinal chemistry optimization effort led to the identification of R-4-(3-hydroxyphenyl)-N,N-7,8-tetramethyl-3,4-dihydroisoquinoline-2(1H)-carboxamide (32a) as a potent inhibitor of human Eg5 (ATPase IC50 104 nM) with good anti-proliferative activity in A2780 cells (IC50 234 nM).

Evaluating Chicago's success in reaching the Healthy People 2000 goal of reducing health disparities

OBJECTIVE

This study was designed to assess Chicago's progress from 1980 to 1998 in addressing the Healthy People 2000 goal of reducing health disparities.

METHODS

Chicago vital statistics and surveillance data were used to calculate black:white rate ratios of mortality and morbidity for 1980-1998. Mortality and morbidity rate ratios were also used to compare people living in areas with the lowest median household income with those living in the highest for 1979-1981, 1991-1993, and 1996-1998. The health measures included mortality associated with leading causes of death; all-cause mortality, incidence rates for two communicable diseases; and two birth outcomes.

RESULTS

Both black:white and low-income:high-income rate ratios monotonically increased for virtually all measures of mortality and morbidity. Almost all of the rate ratios and linear trends were statistically significant. From 1980 to 1998, the black:white rate ratio for all-cause mortality increased by 57% to 2.03. From 1979-1981 to 1996-1998, the low-income:high-income rate ratio for all-cause mortality increased by 56% to 2.68.

CONCLUSIONS

These findings provide clear evidence that disparities in health did not decrease in Chicago. Instead, racial and economic disparities increased for almost all measures of mortality and morbidity used in this study. The fact that the Healthy People 2000 campaign to reduce and then eliminate health disparities was not effective must serve as a stimulus for improved strategies.

Pharmacognosy in the 21st century

The term pharmacognosy as a constituent scientific discipline of pharmacy has been in use for nearly 200 years, and it refers to studies on natural product drugs. During the last half of the 20th century, pharmacognosy evolved from being a descriptive botanical subject to one having a more chemical and biological focus. At the beginning of the 21st century, pharmacognosy teaching in academic pharmacy institutions has been given new relevance, as a result of the explosive growth in the use of herbal remedies (phytomedicines) in modern pharmacy practice, particularly in western Europe and North America. In turn, pharmacognosy research areas are continuing to expand, and now include aspects of cell and molecular biology in relation to natural products, ethnobotany and phytotherapy, in addition to the more traditional analytical method development and phytochemistry. Examples are provided in this review of promising bioactive compounds obtained in two multidisciplinary natural product drug discovery projects, aimed at the elucidation of new plant-derived cancer chemotherapeutic agents and novel cancer chemopreventives, respectively. The systematic study of herbal remedies offers pharmacognosy groups an attractive new area of research, ranging from investigating the biologically active principles of phytomedicines and their mode of action and potential drug interactions, to quality control, and involvement in clinical trials.

Evaluating Chicago's success in reaching the Healthy People 2000 goal of reducing health disparities

OBJECTIVE

This study was designed to assess Chicago's progress from 1980 to 1998 in addressing the Healthy People 2000 goal of reducing health disparities.

METHODS

Chicago vital statistics and surveillance data were used to calculate black:white rate ratios of mortality and morbidity for 1980-1998. Mortality and morbidity rate ratios were also used to compare people living in areas with the lowest median household income with those living in the highest for 1979-1981, 1991-1993, and 1996-1998. The health measures included mortality associated with leading causes of death; all-cause mortality, incidence rates for two communicable diseases; and two birth outcomes.

RESULTS

Both black:white and low-income:high-income rate ratios monotonically increased for virtually all measures of mortality and morbidity. Almost all of the rate ratios and linear trends were statistically significant. From 1980 to 1998, the black:white rate ratio for all-cause mortality increased by 57% to 2.03. From 1979-1981 to 1996-1998, the low-income:high-income rate ratio for all-cause mortality increased by 56% to 2.68.

CONCLUSIONS

These findings provide clear evidence that disparities in health did not decrease in Chicago. Instead, racial and economic disparities increased for almost all measures of mortality and morbidity used in this study. The fact that the Healthy People 2000 campaign to reduce and then eliminate health disparities was not effective must serve as a stimulus for improved strategies.