Angela Chiaviello

Low doses of cisplatin or gemcitabine plus Photofrin/photodynamic therapy : Disjointed cell cycle phase-related activity accounts for synergistic outcome in metastatic non-small cell lung cancer cells (H1299)

We compared the effects of monotherapy (photodynamic therapy or chemotherapy) versus combination therapy (photodynamic therapy plus a specific drug) on the non–small cell lung cancer cell line H1299. Our aim was to evaluate whether the additive/synergistic effects of combination treatment were such that the cytostatic dose could be reduced without affecting treatment efficacy. Photodynamic therapy was done by irradiating Photofrin-preloaded H1299 p53/p16-null cells with a halogen lamp equipped with a bandpass filter. The cytotoxic drugs used were cis-diammine-dichloroplatinum [II] (CDDP or cisplatin) and 2′,2′-difluoro-2′-deoxycytidine (gemcitabine). Various treatment combinations yielded therapeutic effects (trypan blue dye exclusion test) ranging from additive to clearly synergistic, the most effective being a combination of photodynamic therapy and CDDP. To gain insight into the cellular response mechanisms underlying favorable outcomes, we analyzed the H1299 cell cycle profiles and the expression patterns of several key proteins after monotherapy. In our conditions, we found that photodynamic therapy with Photofrin targeted G0-G1 cells, thereby causing cells to accumulate in S phase. In contrast, low-dose CDDP killed cells in S phase, thereby causing an accumulation of G0-G1 cells (and increased p21 expression). Like photodynamic therapy, low-dose gemcitabine targeted G0-G1 cells, which caused a massive accumulation of cells in S phase (and increased cyclin A expression). Although we observed therapeutic reinforcement with both drugs and photodynamic therapy, reinforcement was more pronounced when the drug (CDDP) and photodynamic therapy exert disjointed phase-related cytotoxic activity. Thus, if photodynamic therapy is appropriately tuned, the dose of the cytostatic drug can be reduced without compromising the therapeutic response. [Mol Cancer Ther 2006;5(3):776–85]

Enhancing photodynamyc therapy efficacy by combination therapy: dated, current and oncoming strategies.

Combination therapy is a common practice in many medical disciplines. It is defined as the use of more than one drug to treat the same disease. Sometimes this expression describes the simultaneous use of therapeutic approaches that target different cellular/molecular pathways, increasing the chances of killing the diseased cell. This short review is concerned with therapeutic combinations in which PDT (Photodynamyc Therapy) is the core therapeutic partner. Besides the description of the principal methods used to assess the efficacy attained by combinations in respect to monotherapy, this review describes experimental results in which PDT was combined with conventional drugs in different experimental conditions. This inventory is far from exhaustive, as the number of photosensitizers used in combination with different drugs is very large. Reports cited in this work have been selected because considered representative. The combinations we have reviewed include the association of PDT with anti-oxidants, chemotherapeutics, drugs targeting topoisomerases I and II, antimetabolites and others. Some paragraphs are dedicated to PDT and immuno-modulation, others to associations of PDT with angiogenesis inhibitors, receptor inhibitors, radiotherapy and more. Finally, a look is dedicated to combinations involving the use of natural compounds and, as new entries, drugs that act as proteasome inhibitors.

Targets and Mechanisms of Photodynamic Therapy in Lung Cancer Cells: A Brief Overview

Lung cancer remains one of the most common cancer-related causes of death. This type of cancer typically develops over a period of many years, and if detected at an early enough stage can be eliminated by a variety of treatments including photodynamic therapy (PDT). A critical discussion on the clinical applications of PDT in lung cancer is well outside the scope of the present report, which, in turn focuses on mechanistic and other aspects of the photodynamic action at a molecular and cellular level. The knowledge of these issues at pre-clinical levels is necessary to develop, check and adopt appropriate clinical protocols in the future. This report, besides providing general information, includes a brief overview of present experimental PDT and provides some non-exhaustive information on current strategies aimed at further improving the efficacy, especially in regard to lung cancer cells.

Synthesis and evaluation of folate-based chlorambucil delivery systems for tumor-targeted chemotherapy.

The development of tumor-targeting drug delivery systems, able to selectively transport cytotoxic agents into the tumor site by exploiting subtle morphological and physiological differences between healthy and malignant cells, currently stands as one of the most attractive anticancer strategies used to overcome the selectivity problems of conventional chemotherapy. Owing to frequent overexpression of folate receptors (FRs) on the surface of malignant cells, conjugation of cytotoxic agents to folic acid (FA) via suitable linkers have demonstrated to enhance selective drug delivery to the tumor site. Herein, the chemical synthesis and biological evaluation of two novel folate-conjugates bearing the anticancer agent chlorambucil (CLB) tethered to either an aminoether (4,7,10-trioxa-1,13-tridecanediamine) or a pseudo-β-dipeptide (β-Ala-ED-β-Ala) linker is reported. The two drug delivery systems have been prepared in high overall yields (54% and 34%) through straightforward and versatile synthetic routes. Evaluation of cell specificity was examined using three leukemic cell lines, undifferentiated U937 (not overexpressing FRs, FR(-)), TPA-differentiated U937 (overexpressing FRs, FR(+)), and TK6 (FR(+)) cells. Both conjugates exhibited high specificity only to FR(+) cells (particularly TK6), demonstrating comparable antitumor activity to CLB in its free form. These data confirm the reliability of folate-based drug delivery systems for targeted antitumor therapy; likewise, they lay the foundations for the development of other folate-conjugates with antitumor potential.

Exposure to modeled microgravity induces metabolic idleness in malignant human MCF-7 and normal murine VSMC cells

We investigated the effect of modeled microgravity (MMG) on normal vascular smooth muscle cells (VSMC) and neoplastic human breast cancer cells (MCF‐7). In both cell types, MMG induced partial arrest in G2M and increased p14‐3‐3, HSP70, HSP60 and p21 expression. Cells synchronized by 24 h starvation reentered the normal cycle within 24 h if released in complete medium and exposed to normal gravity, but not if exposed to MMG. Similarly, MMG prevented VSMC and MCF‐7 cells from overcoming growth arrest and re‐synthesizing DNA. This study shows that cells adjust their metabolic rate in response to MMG.

Screening and Scoring of Antimicrobial and Biological Activities of Italian Vulnerary Plants against Major Oral Pathogenic Bacteria

This study aims to evaluate the activity of Italian vulnerary plants against the most important oral pathogenic bacteria. This estimate was accomplished through a fivefold process: (a) a review of ethnobotanical and microbiological data concerning the Italian vulnerary plants; (b) the development of a scoring system to rank the plants; (c) the comparative assessment of microbiological properties; (d) the assessment of potential cytotoxic effects on keratinocyte-like cells and gingival fibroblasts in culture by XTT cell viability assay; (e) clinical evaluation of the most suitable plant extract as antibacterial agent in a home-made mouthwash. The study assays hexane (H), ethanol (E), and water (W) extracts from 72 plants. The agar diffusion method was used to evaluate the activity against Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei, and Actinomyces viscosus. Twenty-two plants showed appreciable activity. The extracts showing the strongest antibacterial power were those from Cotinus coggygria Scop., Equisetum hyemale L., Helichrysum litoreum Guss, Juniperus communis L., and Phyllitis scolopendrium (L.) Newman subsp. scolopendrium. The potential cytotoxic effect of these extracts was assessed. On the basis of these observations, a mouth-rinse containing the ethanolic extract of H. litoreum has been tested in vivo, resulting in reduction of the salivary concentration of S. mutans.

5-aminolaevulinic acid/photo-dynamic therapy and gefitinib in non-small cell lung cancer cell lines: a potential strategy to improve gefitinib therapeutic efficacy

Often, non‐small cell lung cancers (NSCLC) respond only poorly to the tyrosine kinase inhibitor (TKI) gefitinib, which targets the epidermal growth factor receptor (EGFR), these poor responders EGFRs lacking activating mutations. In this study, we have attempted to improve TKI response of NSCLC cell lines (A549 and H1299) devoid of EGFR mutations, by combination of gefitinib and 5‐ALA/photodynamic therapy (PDT).

Combination of photodynamic therapy with aspirin in human‐derived lung adenocarcinoma cells affects proteasome activity and induces apoptosis

Objectives:  Photodynamic treatment (PDT) of human lung carcinoma cells A549 (p53+/+) and H1299 (p53−/−) induces fast but transient stalling of proteasome activity. We have explored the possibility of prolonging this effect by combining PDT with drugs capable of sustaining the stall, and promote apoptosis of surviving cells. We show that aspirin can be used to accomplish this.

Twilight effects of low doses of ionizing radiation on cellular systems: a bird's eye view on current concepts and research

The debate about the health risks from low doses of radiation is vigorous and often acrimonious since many years and does not appear to weaken. Being far from completeness, this review presents only a bird’s eye view on current concepts and research in the field. It is organized and divided in two parts. The first is dedicated to molecular responses determined by radiation-induced DNA ruptures. It focuses its attention on molecular pathways that are activated by ATM and tries to describe the variegated functions and specific roles of Chk2 and p53 and other proteins in sensing, promoting and executing DNA repair. The second part is more concerned with the risk associated with exposure to low dose radiation and possible effects that the radiation-affected cell may undergo. These effects include induction of apoptosis and mitotic catastrophe, bystander effect and genomic instability, senescence and hormetic response. Current hypotheses and research on these issues are briefly discussed.

Cells derived from normal or cancer breast tissue exhibit different growth properties when deprived of arginine

Arginine deprivation impairs cell proliferation more strong in cancer than in normal cells; thus, it has been proposed that such an effect could be exploited for cancer therapy. We have compared the effect of arginine deprivation on normal and cancer cells, studying growth rate, morphology, and protein expression patterns in immortalized human MCF10a cells and in MCF7 cells. Arginine deprivation forces MCF10a cells into irreversible senescence while the vast majority of MCF7 cells become quiescent and resume normal growth following arginine re-addition. Arginine deprivation induced a significant burst of p21cip1 in both cell lines that were reversible in MCF7 and irreversible in MCF10 cells. In the latter cells, p21cip1 increase was accompanied by a time-dependent increase of p16INK4A. Similar effects could be obtained by treating both cell types with α-difluoro-methyl-ornithine, but not with Nω-hydroxy-l-arginine, drugs that interfere specifically but differently with the major pathways of arginine metabolism. Our data suggest that derangement in polyamine synthesis is the main consequence of arginine starvation.