Concurrent inhibition of pBADS99 synergistically improves MEK inhibitor efficacy in KRAS(G12D)-mutant pancreatic ductal adenocarcinoma.

Therapeutic targeting of KRAS-mutant pancreatic ductal adenocarcinoma (PDAC) has remained a significant challenge in clinical oncology. Direct targeting of KRAS has proven difficult, and inhibition of the KRAS effectors have shown limited success due to compensatory activation of survival pathways. Being a core downstream effector of the KRAS-driven p44/42 MAPK and PI3K/AKT pathways governing intrinsic apoptosis, BAD phosphorylation emerges as a promising therapeutic target. Herein, a positive association of the pBADS99/BAD ratio with higher disease stage and worse overall survival of PDAC was observed. Homology-directed repair of BAD to BADS99A or small molecule inhibition of BADS99 phosphorylation by NCK significantly reduced PDAC cell viability by promoting cell cycle arrest and apoptosis. NCK also abrogated the growth of preformed colonies of PDAC cells in 3D culture. Furthermore, high-throughput screening with an oncology drug library to identify potential combinations revealed a strong synergistic effect between NCK and MEK inhibitors in PDAC cells harboring either wild-type or mutant-KRAS. Mechanistically, both mutant-KRAS and MEK inhibition increased the phosphorylation of BADS99 in PDAC cells, an effect abrogated by NCK. Combined pBADS99-MEK inhibition demonstrated strong synergy in reducing cell viability, enhancing apoptosis, and achieving xenograft stasis in KRAS-mutant PDAC. In conclusion, the inhibition of BADS99 phosphorylation enhances the efficacy of MEK inhibition, and their combined inhibition represents a mechanistically based and potentially effective therapeutic strategy for the treatment of KRAS-mutant PDAC.

Tan YQ ，Sun B ，Zhang X ，Zhang S ，Guo H ，Basappa B ，Zhu T ，Sethi G ，Lobie PE ，Pandey V ... -  《Cell Death & Disease》

A novel regimen for pancreatic ductal adenocarcinoma targeting MEK, BCL-xL, and EGFR.

Oncogenic KRAS signaling plays a critical role in pancreatic ductal adenocarcinoma (PDAC) biology. Recent studies indicate that the combination of MEK and BCL-xL inhibition is synthetically lethal and holds promise for some types of solid cancers, however, patient response was poorly observed in PDAC predominantly due to amplified EGFR signaling. Here, we leverage the advantage of the combinational treatment strategy and designed a triplet regimen targeting the comprehensive RAS activation networks through simultaneously blocking MEK/BCL-xL/EGFR. The cytotoxicity of trametinib (MEK inhibitor), DT2216 (BCL-xL degrader) and afatinib (pan-EGFR inhibitor) and their combination was tested in patient-derived, primary PDAC cells using a live cell imaging system. Patient-derived xenograft (PDX) model was employed for the evaluation of the therapeutic efficacy and safety of the combinational regimen. Targeted pathway cascades activities were analyzed using multiplex phosphor-immune assays. In vitro comparisons showed the addition of afatinib as a third agent was statistically superior compared to a doublet of trametinib+DT2216 in suppressing cell growth and inducing cell death in all cell lines tested. This triplet similarly demonstrated significant superiority over the doublet of MEK/BCL-xL inhibition in the in vivo murine model. The triplet regimen was well tolerated in vivo. Overall tumor growth rates were significantly reduced in doublet treatment compared to controls, and further reduced in the triplet treatment group. Pathway analysis revealed the addition of afatinib in triplet regimen further inhibited PI3K/AKT effectors of p90RSK, p70S6K, and GSK3α/β along with a secondary pathway of P38 MAPK. Our study identifies an important contribution of EGFR inhibition to elevate the response of PDAC, supporting a clinical assessment of this triplet combination in patients.

Han S ，Tushoski-Alemán GW ，Zhang P ，Zheng G ，Zhou D ，Huo Z ，Licht J ，George TJ ，Allegra C ，Trevino JG ，Hughes SJ ... -  《NEOPLASIA》

Enhancing efficacy of the MEK inhibitor trametinib with paclitaxel in KRAS-mutated colorectal cancer.

Ghosh S ，Fan F ，Powell R ，Park YS ，Stephan C ，Kopetz ES ，Ellis LM ，Bhattacharya R ... -  《-》

pH-responsive targeted nanoparticles release ERK-inhibitor in the hypoxic zone and sensitize free gemcitabine in mutant K-Ras-addicted pancreatic cancer cells and mouse model.

Therapeutic options for managing Pancreatic ductal adenocarcinoma (PDAC), one of the deadliest types of aggressive malignancies, are limited and disappointing. Therefore, despite suboptimal clinical effects, gemcitabine (GEM) remains the first-line chemotherapeutic drug in the clinic for PDAC treatment. The therapeutic limitations of GEM are primarily due to poor bioavailability and the development of chemoresistance resulting from the addiction of mutant-K-RAS/AKT/ERK signaling-mediated desmoplastic barriers with a hypoxic microenvironment. Several new therapeutic approaches, including nanoparticle-assisted drug delivery, are being investigated by us and others. This study used pH-responsive nanoparticles encapsulated ERK inhibitor (SCH772984) and surface functionalized with tumor-penetrating peptide, iRGD, to target PDAC tumors. We used a small molecule, SCH772984, to target ERK1 and ERK2 in PDAC and other cancer cells. This nanocarrier efficiently released ERKi in hypoxic and low-pH environments. We also found that the free-GEM, which is functionally weak when combined with nanoencapsulated ERKi, led to significant synergistic treatment outcomes in vitro and in vivo. In particular, the combination approaches significantly enhanced the GEM effect in PDAC growth inhibition and prolonged survival of the animals in a genetically engineered KPC (LSL-KrasG12D/+/LSL-Trp53R172H/+/Pdx-1-Cre) pancreatic cancer mouse model, which is not observed in a single therapy. Mechanistically, we anticipate that the GEM efficacy was increased as ERKi blocks desmoplasia by impairing the production of desmoplastic regulatory factors in PDAC cells and KPC mouse tumors. Therefore, 2nd generation ERKi (SCH 772984)-iRGD-pHNPs are vital for the cellular response to GEM and denote a promising therapeutic target in PDAC with mutant K-RAS.

Dutta D ，Ray P ，De A ，Ghosh A ，Hazra RS ，Ghosh P ，Banerjee S ，Diaz FJ ，Upadhyay SP ，Quadir M ，Banerjee SK ... -  《PLoS One》

Targeting of the G9a, DNMT1 and UHRF1 epigenetic complex as an effective strategy against pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer with limited treatment options and a poor prognosis. The critical role of epigenetic alterations such as changes in DNA methylation, histones modifications, and chromatin remodeling, in pancreatic tumors progression is becoming increasingly recognized. Moreover, in PDAC these aberrant epigenetic mechanisms can also limit therapy efficacy. This study aimed to investigate the expression and prognostic significance of a key epigenetic complex encompassing DNA methyltransferase-1 (DNMT1), the histone methyltransferase G9a, and the scaffold protein UHRF1 in PDAC. We also evaluated the therapeutic potential of an innovative inhibitor targeting these epigenetic effectors. Immunohistochemical analysis of DNMT1, G9a, and UHRF1 expression was conducted in human PDAC tissue samples. Staining was semi-quantitatively scored, and overexpression was defined as moderate to strong positivity. The prognostic impact was assessed by correlating protein expression with patient survival. The antitumoral effects of the dual DNMT1-G9a inhibitor CM272 were tested in PDAC cell lines, followed by transcriptomic analyses to identify underlying mechanisms. The in vivo antitumoral efficacy of CM272 was evaluated in PDAC xenograft and syngeneic mouse models, both alone and in combination with anti-PD1 immunotherapy. DNMT1, G9a, and UHRF1 were significantly overexpressed in PDAC cells and stroma compared to normal pancreatic tissues. Simultaneous overexpression of the three proteins was associated with significantly reduced survival in resected PDAC patients. CM272 exhibited potent antiproliferative activity in PDAC cell lines, inducing apoptosis and altering key metabolic and cell cycle-related genes. CM272 also enhanced chemotherapy sensitivity and significantly inhibited tumor growth in vivo without detectable toxicity. Combination of CM272 with anti-PD1 therapy further improved antitumor responses and immune cell infiltration, particularly CD4 + and CD8 + T cells. The combined overexpression of DNMT1, G9a, and UHRF1 in PDAC is a strong predictor of poor prognosis. CM272, by targeting this epigenetic complex, shows promising therapeutic potential by inducing apoptosis, reprogramming metabolic pathways, and enhancing immune responses. The combination of CM272 with immunotherapy offers a novel, effective treatment strategy for PDAC.

Oyon D ，Lopez-Pascual A ，Castello-Uribe B ，Uriarte I ，Orsi G ，Llorente S ，Elurbide J ，Adan-Villaescusa E ，Valbuena-Goiricelaya E ，Irigaray-Miramon A ，Latasa MU ，Martinez-Perez LA ，Bonetti LR ，Prosper F ，Ponz-Sarvise M ，Vicent S ，Pineda-Lucena A ，Ruiz-Clavijo D ，Sangro B ，Larracoechea UA ，Tian TV ，Casadei-Gardini A ，Amat I ，Arechederra M ，Berasain C ，Urman JM ，Avila MA ，Fernandez-Barrena MG ... -  《-》