GP-2250, a novel anticancer agent, inhibits the energy metabolism, activates AMP-Kinase and impairs the NF-kB pathway in pancreatic cancer cells

Maintenance Therapy for Pancreatic Cancer, a New Approach Based on the Synergy between the Novel Agent GP-2250 (Misetionamide) and Gemcitabine

The novel Oxathiazinane derivative GP-2250 (Misetionamide) displays antineoplastic activity in vitro and in vivo, as previously shown in pancreatic cancer cells and in patient-derived mouse xenografts (PDX). Currently, GP 2250 is under phase I clinical trial in pancreatic ductal adenocarcinoma (PDAC). GP-2250 in combination with Gemcitabine displays a high synergistic capacity in various primary and established pancreatic cancer cell lines. Additionally, in the eight PDX models tested, the drug combination was superior in reducing tumor volume with an aggregate tumor regression (ATR) of 74% compared to Gemcitabine alone (ATR: 10%). Similarly, in a PDX maintenance setting following two weeks of treatment with nab-Paclitaxel plus Gemcitabine, the combination of GP-2250 plus Gemcitabine resulted in outstanding tumor control (ATR: 79%) compared to treatment with Gemcitabine alone (ATR: 19%). Furthermore, GP-2250 reduced the ratio of tumor-initiating CD133+ markers on the surface of PDAC cells in spheroid cultures, indicating a possible mechanism for the synergistic effect of both substances. Considering the high tolerability of GP 2250, these results may open up a new approach to maintenance therapy with GP-2250/Gemcitabine combination following nab-Paclitaxel plus Gemcitabine as first-line treatment.

The trend toward more target therapy in pancreatic ductal adenocarcinoma

INTRODUCTION

Despite the considerable progress made in cancer treatment through the development of target therapies, pancreatic ductal adenocarcinoma (PDAC) continues to exhibit resistance to this category of drugs. As a result, chemotherapy combination regimens remain the primary treatment approach for this aggressive cancer.

AREAS COVERED

In this review, we provide an in-depth analysis of past and ongoing trials on both well-known and novel targets that are being explored in PDAC, including PARP, EGFR, HER2, KRAS, and its downstream and upstream pathways (such as RAF/MEK/ERK and PI3K/AKT/mTOR), JAK/STAT pathway, angiogenesis, metabolisms, epigenetic targets, claudin, and novel targets (such as P53 and plectin). We also provide a comprehensive overview of the significant trials for each target, allowing a thorough glimpse into the past and future of target therapy.

EXPERT OPINION

The path toward implementing a target therapy capable of improving the overall survival of PDAC is still long, and it is unlikely that a monotherapy target drug will fulfill a meaningful role in addressing the complexity of this cancer. Thus, we discuss the future direction of target therapies in PDAC, trying to identify the more promising target and combination treatments, with a special focus on the more eagerly awaited ongoing trials.

Second-Line Treatment of Pancreatic Adenocarcinoma: Shedding Light on New Opportunities and Key Talking Points from Clinical Trials

Despite improvements in overall cancer mortality, deaths related to pancreatic cancer continue to rise. Following first-line treatment, second-line options are significantly limited. Classically, first-line treatment consisted of either gemcitabine or 5-fluorouracil based systemic chemotherapy. Upon progression of disease or recurrence, subsequent second-line treatment is still gemcitabine or 5-fluorouracil based chemotherapy, depending on what was used in the first line and the timing of progression or recurrence. A better understanding of the molecular underpinnings of pancreatic adenocarcinoma (PDAC) has led to new treatment strategies including specifically targeting the desmoplastic stroma, cytokine signaling and actionable mutations. Furthermore, efforts are also directed to enhance the immunogenicity profile of PDAC's well-established immunologically "cold" tumor microenvironment. More recently, the outstanding response rates of chimeric antigen receptor T (CAR-T) cells in hematologic malignancies, have led to clinical trials to evaluate the treatment modality in PDAC. In this review, we summarize recently presented clinical trials for metastatic pancreatic adenocarcinoma with novel treatment approaches in the second line and beyond.

In Vitro Experiments on the Effects of GP-2250 on BRAF-Mutated Melanoma Cell Lines and Benign Melanocytes

Enhanced glycolysis (Warburg effect) driven by the BRAF oncogene, dysregulated GAPDH expression, and activation of the PI3K/AKT/mTOR signaling pathway may significantly contribute to the resistance-targeted therapy of BRAF-mutated melanomas. Therefore, we aimed to study for the first time the anti-tumor activity of the GAPDH inhibitor GP-2250 in BRAF-mutated melanoma cell lines and benign melanocytes. We employed three melanoma cell lines and one primary melanocyte cell line (Ma-Mel-61a, Ma-Mel-86a, SH-4 and ATCC-PCS-200-013, respectively), which were exposed to different GP-2250 doses. GP-2250's effects on cell proliferation and viability were evaluated by means of the BrdU and MTT assays, respectively. The RealTime-Glo Annexin V Apoptosis and Necrosis Assay was performed for the evaluation of apoptosis and necrosis induction. RT-PCR and western blotting were implemented for the determination of AKT and STAT3 gene and protein expression analyses, respectively. The melanoma cell lines showed a dose-dependent response to GP-2250 during BrDU and MTT testing. The RealTime-Glo Annexin V assay revealed the heterogenous impact of GP-2250 on apoptosis as well as necrosis. With respect to the melanoma cell lines Ma-Mel-86a and SH-4, the responses and dosages were comparable to those used for the MTT viability assay. Using the same dose range of GP-2250 administered to melanoma cells, however, we observed neither the noteworthy apoptosis nor necrosis of GP-2250-treated benign melanocytes. The gene expression profiles in the melanoma cell lines for AKT and STAT3 were heterogenous, whereby AKT as well as STAT3 gene expression were most effectively downregulated using the highest GP-2250 doses. Immunoblotting revealed that there was a time-dependent decrease in protein expression at the highest GP-2250 dose used, whereas a time- as well as dose-dependent AKT decrease was predominantly observed in Ma-Mel-61a. The STAT3 protein expression of Ma-Mel-86a and SH-4 was reduced in a time-dependent pattern at lower and moderate doses. STAT3 expression in Ma-Me-61a was barely altered by GP-2250. In conclusion, GP-2250 has anti-neoplastic effects in BRAF-mutated melanoma cell lines regarding tumor cell viability, proliferation, and apoptosis/necrosis. GP-2250 is able to downregulate the gene and protein expression of aberrant tumorigenic pathways in melanoma cell lines. Since GP-2250 is a GAPDH inhibitor, the substance may be a promising combination therapy for tumors presenting the Warburg effect, such as melanoma.