Paul K Strudler: The Oracle of RAD.

Paul Strudler who facilitated the support of photodynamic therapy by an NIH study section.

Rational drug design and synthesis of new α-Santonin derivatives as potential COX-2 inhibitors.

Sesquiterpene compounds are widely known for their numerous pharmacological activities. Herein the focus of the authors was on α-Santonin, a sesquiterpene lactone from the Artemisia genus: the aim was to determine whether α-Santonin could be considered in the treatment of inflammation and pain. To this purpose, a small series of derivatives was designed and screened in silico against the enzyme COX-2 along with the parent compound.

Induction of prosurvival molecules during treatment: rethinking therapy options for photodynamic therapy.

Photodynamic therapy (PDT) not only causes direct cytotoxicity to malignant cells within a tumor but also appears to have both direct and indirect effects on nonmalignant components of the tumor microenvironment. A host of preclinical studies have been performed to document how PDT modulates the tumor microenvironment. This article explores the role of cellular components such as the hypoxia-inducible factor 1α, vascular endothelial growth factor, cyclooxygenase-2, matrix metalloproteinases, the antiapoptotic protein survivin, and 17-AAG (an inhibitor of heat shock proteins), with the hope that combined modality regimens targeting these processes may improve PDT tumor responsiveness.

Pro-apoptotic and anti-inflammatory properties of the green tea constituent epigallocatechin gallate increase photodynamic therapy responsiveness.

Background: A polyphenol constituent of green tea, epigallocatechin gallate (EGCG), has anti-carcinogenic properties. A growing number of studies document EGCG-mediated induction of apoptotic pathways and inhibition of pro-survival factors when combined with chemotherapy or radiation. We evaluated the efficacy of EGCG in modulating photofrin (PH)-mediated photodynamic therapy (PDT) responses.

Enhancement of photodynamic therapy by 2,5-dimethyl celecoxib, a non-cyclooxygenase-2 inhibitor analog of celecoxib.

Photodynamic therapy (PDT) effectiveness can be improved by employing combined modality approaches involving pharmaceuticals targeting the tumor microenvironment and/or tumor cell death pathways. In one approach, combining PDT with celecoxib improves long-term tumoricidal activity without increasing normal tissue photosensitization. However, side effects arising from the use of coxib based cyclooxygenase-2 (COX-2) inhibitors, including cardiovascular injury, decreases the clinical applications of this class of compounds.

Targeting the tumor microenvironment using photodynamic therapy combined with inhibitors of cyclooxygenase-2 or vascular endothelial growth factor.

Photodynamic therapy (PDT) involves the administration of a photosensitizer (PS) followed by localized exposure of a targeted tissue to PS adsorbing light. PDT induces cytotoxicity to exposed malignant cells and also effects non-malignant components of the tumor microenvironment. This indirect action of PDT leads to inflammatory and proangiogenic responses and modulates treatment effectiveness.

Identification of MAP kinase pathways involved in COX-2 expression following photofrin photodynamic therapy.

Photodynamic therapy (PDT) using the photosensitizer Photofrin is approved for the clinical treatment of solid tumors. PDT causes cytotoxic oxidative stress, but additionally induces prosurvival molecules such as cyclooxygenase-2 (COX-2). Combining PDT with COX-2 inhibitors increases the efficacy of in vivo treatment.

Targeting the 90 kDa heat shock protein improves photodynamic therapy.

The geldanamycin derivative, 17-allylamino-17-demethoxygeldanamycin (17-AAG), binds to the amino-terminal ATP binding pocket of the 90 kDa heat shock protein (Hsp-90) and inhibits this chaperone from stabilizing client proteins involved with the malignant phenotype. We examined the effects of a combined modality protocol involving photodynamic therapy (PDT) and 17-AAG in mouse mammary carcinoma cells and tumors. PDT increased the expression of the anti-apoptotic and pro-angiogenic proteins survivin, Akt, HIF-1alpha, MMP-2 and VEGF in tumor tissue and this expression decreased significantly when 17-AAG was included in the treatment regimen.

Cyclooxygenase-2 expression induced by photofrin photodynamic therapy involves the p38 MAPK pathway.

Photodynamic therapy (PDT), using the porphyrin photosensitizer Photofrin (PH), is approved for the clinical treatment of solid tumors. In addition to the direct cytotoxic responses of PH-PDT-mediated oxidative stress, this procedure also induces expression of angiogenic and prosurvival molecules including cyclooxygenase-2 (COX-2). In vivo treatment efficacy is improved when PH-PDT is combined with inhibitors of COX-2.

Multiple components of photodynamic therapy can phosphorylate Akt.

A growing number of clinically relevant molecular and cellular responses are observed following photodynamic therapy (PDT). PDT-mediated oxidative stress and PDT-induced tissue hypoxia can elicit the transcriptional and/or translational expression of genes associated with cellular stress, inflammation, angiogenesis, immuno-modulation, apoptosis and signal transduction. One of the signaling molecules activated by oxidative stress is Akt/protein kinase B.

Survivin, a member of the inhibitor of apoptosis family, is induced by photodynamic therapy and is a target for improving treatment response.

We observed that photodynamic therapy (PDT) induces the expression and phosphorylation of the inhibitor of apoptosis (IAP) protein survivin in murine and human cancer cells and tumors. Survivin inhibits caspase-9, blocks apoptosis, and is associated with resistance to chemotherapy and radiation. Survivin is a client protein for the 90-kDa heat shock protein (Hsp-90), and the binding of survivin to Hsp-90 assists in the maturation, proper folding, assembly, and transport of this IAP protein.

Photodynamic therapy: combined modality approaches targeting the tumor microenvironment.

Background And Objectives: Photodynamic therapy causes direct cytotoxicity to malignant cells within a tumor. Photodynamic therapy (PDT) can also have both direct and indirect effects upon various non-malignant components of the tumor microenvironment. This action can lead to PDT-mediated angiogenesis and inflammation, which are emerging as important determinants of PDT responsiveness.

Avastin enhances photodynamic therapy treatment of Kaposi's sarcoma in a mouse tumor model.

The goal of the current study was to determine if the antiangiogenic drug Avastin would improve the effectiveness of Photodynamic Therapy (PDT) in a xenograft model of Kaposi's sarcoma (KS). Human KS-Imm tumors transplanted in nude mice were treated with Photofrin-mediated PDT. Expression parameters of proangiogenic molecules were documented and the tumoricidal effectiveness of PDT combined with the VEGF inhibitor Avastin was determined.

Celecoxib and NS-398 enhance photodynamic therapy by increasing in vitro apoptosis and decreasing in vivo inflammatory and angiogenic factors.

Photodynamic therapy (PDT) elicits both apoptotic and necrotic responses within treated tumors and produces microvascular injury leading to inflammation and hypoxia. PDT also induces expression of angiogenic and survival molecules including vascular endothelial growth factor, cyclooxygenase-2 (COX-2), and matrix metalloproteinases. Adjunctive administration of inhibitors to these molecules improves PDT responsiveness.

CHOP activation by photodynamic therapy increases treatment induced photosensitization.

Background And Objectives: C/EBP homologous protein (CHOP) is an endoplasmic reticulum (ER) stress inducible transcription factor involved in the development of apoptosis, growth arrest, and differentiation. CHOP deficient (chop - / - ) mouse embryonic fibroblasts (MEFs) exposed to ER stresses such as tunicamycin exhibit decreased apoptosis and reduced toxicity when compared to chop + / + control cells. Overexpression of the 70 kDa heat shock stress protein (HSP-70) can inhibit apoptotic pathways.

The matrix metalloproteinase inhibitor prinomastat enhances photodynamic therapy responsiveness in a mouse tumor model.

Photodynamic therapy (PDT) clinical results are promising; however, tumor recurrences can occur and, therefore, methods for improving treatment efficacy are needed. PDT elicits direct tumor cell death and microvascular injury as well as expression of angiogenic, inflammatory, and prosurvival molecules. Preclinical studies combining antiangiogenic drugs or cyclooxygenase-2 inhibitors with PDT show improved treatment responsiveness (A.

Cyclooxygenase-2 inhibitor treatment enhances photodynamic therapy-mediated tumor response.

Photodynamic therapy (PDT) continues to be used in the treatment of solid tumors. Clinical results are promising, but the therapy has not been optimized, and tumor recurrences can occur. Recently, it has been shown that inhibitors of cyclooxygenase (COX)-2 can be effective in combination with conventional chemotherapy and radiation therapy.