Verteporfin- and sodium porfimer-mediated photodynamic therapy enhances pancreatic cancer cell death without activating stromal cells in the microenvironment.

Jingjing Lu,Michael J Levy,Tayyaba Hasan,Cadman L Leggett,Kenneth K Wang,Bhaskar Roy,Brian Pogue,Marlys Anderson

doi:10.1117/1.jbo.24.11.118001

Abstract

.The goal of our study was to determine the susceptibility of different pancreatic cell lines to clinically applicable photodynamic therapy (PDT). The efficacy of PDT of two different commercially available photosensitizers, verteporfin and sodium porfimer, was compared using a panel of four different pancreatic cancer cell lines, PANC-1, BxPC-3, CAPAN-2, and MIA PaCa-2, and an immortalized non-neoplastic pancreatic ductal epithelium cell line, HPNE. The minimum effective concentrations and dose-dependent curves of verteporfin and sodium porfimer on PANC-1 were determined. Since pancreatic cancer is known to have significant stromal components, the effect of PDT on stromal cells was also assessed. To mimic tumor–stroma interaction, a co-culture of primary human fibroblasts or human pancreatic stellate cell (HPSCs) line with PANC-1 was used to test verteporfin-PDT-mediated cell death of PANC-1. Two cytokines (TNF- and IL-) were used for stimulation of primary fibroblasts (derived from human esophageal biopsies) or HPSCs. The increased expression of smooth muscle actin (-SMA) confirmed the activation of fibroblasts or HPSC upon treatment with TNF- and IL-. Cell death assays showed that both sodium porfimer- and verteporfin-mediated PDT-induced cell death in a dose-dependent manner. However, verteporfin-PDT treatment had a greater efficiency with lower concentration than sodium porfimer-PDT in the PANC-1 incubated with stimulated fibroblasts or HPSC. Moreover, activation of stromal cells did not affect the treatment of the pancreatic cancer cell lines, suggesting that the effects of PDT are independent of the inflammatory microenvironment found in this two-dimensional culture model of cancers.

Highlights

Pancreatic cancer is the fourth leading cause of cancer-related deaths in the United States, with an estimated 43,090 deaths in 2017.1 Pancreatic ductal adenocarcinoma (PDAC) is the most common form of pancreatic cancer and is notoriously difficult to treat
We developed an in-vitro co-culture model comprised of pancreatic cancer cells with activated fibroblasts or human pancreatic stellate cells (HPSCs) in cell inserts to illustrate their influence on Photodynamic therapy (PDT) to address whether there was a tissue-specific difference between fibroblasts derived from low-grade esophageal dysplasia and HPSCs from pancreatic origin
Chemical, biological properties, and quantum efficiency, every photosensitizer has certain benefit to be used in PDT; selecting the most appropriate photosensitizers for the best clinical outcome requires a careful analysis of all the factors

Summary

Introduction

Pancreatic cancer is the fourth leading cause of cancer-related deaths in the United States, with an estimated 43,090 deaths in 2017.1 Pancreatic ductal adenocarcinoma (PDAC) is the most common form of pancreatic cancer and is notoriously difficult to treat. Surgical resection is the only potentially curative treatment available for early stage PDAC patients, and chemotherapy and radiation therapy have limited success in lengthening patients’ survival with later stage disease.[2] more than half (52%) of patients are diagnosed at advanced stages and are not eligible for surgical resection, resulting in a 5-year survival rate of only 3%.1. New diagnostic and therapeutic modalities are urgently needed to improve the survival of PDAC patients beyond the minimal benefit that they receive today. Photodynamic therapy (PDT)[3] is a light-based therapeutic modality, which has been approved in the US, Japan, China, Korea, UK, and several other European countries for the treatment of head and neck, bladder, esophageal, and endobronchial cancers.[4,5] Upon activation with a specific wavelength of light and depending on the interval between drug administration and photoradiation, PDT-induced cell death can be mediated by cellular and vascular modes. An activated photosensitizer generates highly reactive molecular species and singlet oxygen, which induce tumor cell death by direct cytotoxicity and indirect effects, such as microvascular damage, apoptosis, autophagy, and immune responses.[5,6] Apoptotic [intrinsic (mitochondriamediated) and extrinsic (the death receptor-mediated)]6,7 and necrotic pathways[8] play a role in PDT-mediated cell death

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