Targeting Protease-Activated Receptor-1 with Cell-Penetrating Pepducins in Lung Cancer

Abstract

Protease-activated receptors (PARs) are G-proteincoupled receptors that are activated by proteolytic cleavage and generation of a tethered ligand. High PAR1 expression has been documented in a variety of invasive cancers of epithelial origin. In the present study, we investigated the contribution of the four PAR family members to motility of lung carcinomas and primary tumor samples from patients. We found that of the four PARs, only PAR1 expression was highly increased in the lung cancer cell lines. Primary lung cancer cells isolated from patient lung tumors migrated at a 10-to 40-fold higher rate than epithelial cells isolated from nonmalignant lung tissue. Cellpenetrating pepducin inhibitors were generated against the first (i1) and third (i3) intracellular loops of PAR1 and tested for their ability to inhibit PAR1-driven migration and extracellular regulated kinase (ERK)1/2 activity. The PAR1 pepducins showed significant inhibition of cell migration in both primary and established cell lines similar to silencing of PAR1 expression with short hairpin RNA (shRNA). Unlike i1 pepducins, the i3 loop pepducins were effective inhibitors of PAR1-mediated ERK activation and tumor growth. Comparable in efficacy with Bevacizumab, monotherapy with the PAR1 i3 loop pepducin P1pal-7 provided significant 75% inhibition of lung tumor growth in nude mice. We identify the PAR1-ERK1/2 pathway as a feasible target for therapy in lung cancer. Lung cancer is the leading cause of cancer deaths in the United States and worldwide, and is the second most common cancer overall. 1 The majority of patients eventually develop distant metastases, which leads to substantial morbidity and mortality. Currently available chemotherapeutic regimens for the treatment of non-small-cell lung cancer (NSCLC) include combinations of cisplatin or carboplatin, and etoposide, paclitaxel, docetaxel, gemcitabine, vinorelbin, and irinotecan. These regimens are generally not curative and may confer modest prolongation of life and symptomatic relief. 2,3 More recently, targeted therapies have become available for the treatment of lung cancer. These include small molecules and antibodies that target epidermal growth factor receptor and vascular endothelial growth factor receptor. However, the currently available molecular therapies still result in relatively modest prolongation of median and overall survival, pointing to the necessity for developing more effective treatment modalities for patients with advanced NSCLC.Emerging evidence has identified protease activated receptor-1 (PAR1) as a promising target to impact tumor progression, metastasis, and angiogenesis in a variety of cancers including breast, ovarian, melanoma, prostate, and colon cancer. 4 -7 However, the role of PAR1 and the other PAR family members in lung cancer is largely unexplored. To date, four different PARs have been identified: PAR1, PAR2, PAR3, and PAR4. 8,9 -13 PAR1 originally was discovered on platelets and serves as the prototype for this specialized class of proteolytically activ...

Dabigatran Potentiates Gemcitabine-Induced Growth Inhibition of Pancreatic Cancer in Mice

“…levels of PAR-1 are increased in several cancer types, such as breast and lung cancer (6)(7)(8). Moreover, these increased PAR-1 levels are associated with disease progression and reduced overall survival in breast and lung cancer patients (9,10).…”

The activation of protease-activated receptor 1 mediates proliferation and invasion of nasopharyngeal carcinoma cells

“…It has been reported that PAR-1 was expressed highly in many types of cancer, such as breast cancer (9), malignant melanoma (10), prostate cancer (11), colon cancer (12), lung cancer (13), oral squamous cell carcinoma (14), esophageal cancer (15), and renal cell carcinoma (16). Early study by Even-Ram et al (9) demonstrated that PAR-1 expression levels were correlated with degree of invasiveness in both primary breast tissue specimens and established cancer cell lines.…”

Prospects for use of peptides and their derivatives, structurally corresponding to the G protein-coupled receptors, in medicine

“…Следует отметить, что экспрессия PAR1-рецепторов, но не других типов PAR, сильно повышается в клеточных культурах рака лёгкого, полученных от пациентов, страдающих этим заболеванием. Обнаружено, что пепдуцины с активностью PAR1-антагонистов, производные ЦП-1 и ЦП-3 PAR1-рецептора, существенно снижают миграцию клеток, которая регулируется через посредство PAR1-рецептора, причём этот эффект выявляется как в первичных культурах клеток рака лёгкого, полученных от пациентов, страдающих этим заболеванием, так и в перевиваемых культурах [16]. Наиболее эффективный пепдуцин P1pal-7 на 75-95% снижал инвазивное прорастание в трёхмерные матрицы клеток карциномы лёгких Льюис, метастазирующей опухоли мышей [27].…”

“…Терапевтический эффект пепдуцина P1pal-7 при лечении мышей с раком лёгкого составил 75% от такового бевацизумаба -противоопухолевого препарата, представляющего собой рекомбинантные гиперхимерные моноклональные IgG1 антитела, которые селективно связываются и ингибируют биологическую активность фактора роста эндотелия сосудов [16].…”

“…Таким образом, действие GPCR-пептида может реализовываться только в присутствии гомологичного или комплиментарного ему рецептора и характеризуется рецепторной и тканевой специфичностью, что и было доказано в целом ряде работ [4,[10][11][12][13][14][15][16][17][18]. Специфичность и направленность действия GPCR-пептидов, производных ЦП, а также обнаружение у них активности in vitro и in vivo открыло новые пути для создания на их основе регуляторов гормональных сигнальных систем.…”