MIA PaCa-2 Cells Research Articles

Development of novel imipridone derivatives with potent anti-cancer activities as human caseinolytic peptidase P (hClpP) activators

Based on a clinically staged small molecular hClpP activator ONC201, a class of imipridone derivatives was designed and synthesized. These compounds were evaluated in a protease hydrolytic assay, as well as cell growth inhibition assays in three cancer cell lines, MIA PACA-2, HCT116, and MV4-11. A number of compounds that can more potently activate hClpP and more effectively inhibit cell growth in the three cancer cell lines than ONC201 were identified. The most potent compound, ZYZ-17, activated hClpP with an EC50 value of 0.24 µM and inhibited the growth of the three cancer cell lines with IC50 values of less than 10 nM. Mechanism studies for ZYZ-17 revealed that it potently activates cellular hClpP, efficiently induces the degradation of hClpP substrates, and robustly induces apoptosis in the three cancer cell lines. Furthermore, ZYZ-17 demonstrated a promising pharmacokinetic (PK) profile and exhibited highly potent in vivo antitumor activity in a pancreatic cancer MIA PACA-2 xenograft model in BALB/c nude mice.

Cell fate simulation reveals cancer cell features in the tumor microenvironment

To elucidate the dynamic evolution of cancer cell characteristics within the tumor microenvironment (TME), we developed an integrative approach combining single-cell tracking, cell fate simulation, and three-dimensional (3D) TME modeling. We began our investigation by analyzing the spatiotemporal behavior of individual cancer cells in cultured pancreatic (MiaPaCa2) and cervical (HeLa) cancer cell lines, with a focus on the α2-6 sialic acid (α2-6Sia) modification on glycans, which is associated with cell stemness. Our findings revealed that MiaPaCa2 cells exhibited significantly higher levels of α2-6Sia modification, correlating with enhanced reproductive capabilities, whereas HeLa cells showed less prevalence of this modification. To accommodate the in vivo variability of α2-6Sia levels, we employed a cell fate simulation algorithm that digitally generates cell populations based on our observed data while varying the level of sialylation, thereby simulating cell growth patterns. Subsequently, we performed a 3D TME simulation with these deduced cell populations, considering the microenvironment that could impact cancer cell growth. Immune cell landscape information derived from 193 cervical and 172 pancreatic cancer cases was used to estimate the degree of the positive or negative impact. Our analysis suggests that the deduced cells generated based on the characteristics of MiaPaCa2 cells are less influenced by the immune cell landscape within the TME compared to those of HeLa cells, highlighting that the fate of cancer cells is shaped by both the surrounding immune landscape and the intrinsic characteristics of the cancer cells.

Identification of 6-Fluorine-Substituted Coumarin Analogues as POLRMT Inhibitors with High Potency and Safety for Treatment of Pancreatic Cancer.

Increasing evidence has demonstrated that oxidative phosphorylation (OXPHOS) is closely associated with the progression of pancreatic cancer (PC). Given its central role in mitochondrial transcription, the human mitochondrial RNA polymerase (POLRMT) is a promising target for developing PC treatments. Herein, structure-activity relationship exploration led to the identification of compound S7, which was the first reported POLRMT inhibitor possessing single-digit nanomolar potency of inhibiting PC cells proliferation. Mechanistic studies showed that compound S7 exerted antiproliferative effects without affecting the cell cycle, apoptosis, mitochondrial membrane potential (MMP), or intracellular reactive oxygen species (ROS) levels specifically in MIA PaCa-2 cells. Notably, compound S7 inhibited tumor growth in MIA PaCa-2 xenograft tumor model with a tumor growth inhibition (TGI) rate of 64.52% demonstrating significant improvement compared to the positive control (44.80%). In conclusion, this work enriched SARs of POLRMT inhibitors, and compound S7 deserved further investigations of drug-likeness as a candidate for PC treatment.

Targeting Pancreatic Cancer with Novel Nicolaioidesin C Derivatives: Molecular Mechanism, In Vitro, and In Vivo Evaluations.

Pancreatic cancer, one of the deadliest cancers with the lowest 5-year survival rate, often develops resistance to gemcitabine-based chemotherapies. The hypovascular nature of pancreatic tumors forces cancer cells to adapt to nutrient-depleted tumor microenvironments. Conventional anticancer agents targeting rapidly dividing cancer cells under nutrient-rich conditions are largely ineffective against adapted pancreatic cancer cells. Thus, targeting cancer cells under nutrient starvation, termed the "antiausterity strategy", may be effective for pancreatic cancer. This study examined nicolaioidesin C (Nic-C) derivatives as antiausterity agents. Among the 32 derivatives, Nic-15 (4n) exhibited superior cytotoxicity against MIA PaCa-2 and PANC-1 pancreatic cancer cells, inhibited MIA PaCa-2 cell migration and colony formation, and modulated the PI3K/Akt/mTOR pathway, while reducing the ER stress markers induced by gemcitabine. Nic-15 was found to inhibit tumor growth and enhance the efficacy of gemcitabine in an in vivo xenograft model. Nic-15 in combination with gemcitabine may be an effective strategy for the treatment of pancreatic cancer.

DDX21 functions as a potential novel oncopromoter in pancreatic ductal adenocarcinoma: a comprehensive analysis of the DExD box family

BackgroundPancreatic ductal adenocarcinoma (PDAC) is a highly lethal tumor with an ill-defined pathogenesis. DExD box (DDX) family genes are widely distributed and involved in various RNA metabolism and cellular biogenesis; their dysregulation is associated with aberrant cellular processes and malignancies. However, the prognostic significance and expression patterns of the DDX family in PDAC are not fully understood. The present study aimed to explore the clinical value of DDX genes in PDAC.MethodsDifferentially expressed DDX genes were identified. DDX genes related to prognostic signatures were further investigated using LASSO Cox regression analysis. DDX21 protein expression was analyzed using the UALCAN and human protein atlas (HPA) online tools and confirmed in 40 paired PDAC and normal tissues through Tissue Microarrays (TMA). The independent prognostic significance of DDX21 in PDAC was determined through the construction of nomogram models and calibration curves. The functional roles of DDX21 were investigated using gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA). Cell proliferation, invasion, and migration were assessed using Cell Counting Kit-8, colony formation, Transwell, and wound healing assays.ResultsUpregulation of genes related to prognostic signatures (DDX10, DDX21, DDX60, and DDX60L) was significantly associated with poor prognosis of patients with PDAC based on survival and recurrence time. Considering the expression profile and prognostic values of the signature-related genes, DDX21 was finally selected for further exploration. DDX21 was overexpressed significantly at both the mRNA and protein levels in PDAC compared to normal pancreatic tissues. DDX21 expression, pathological stage, and residual tumor were significant independent prognostic indicators in PDAC. Moreover, functional enrichment analysis revealed that Genes co-expressed with DDX21 are predominantly involved in RNA metabolism, helicase activity, ribosome biogenesis, cell cycle, and various cancer-related pathways, such as PI3K/Akt signaling pathway and TGF-β signaling pathway. Furthermore, in vitro experiments confirmed that the knockdown of DDX21 significantly reduced MIA PaCa-2 cell viability, proliferation, migration, and invasion.ConclusionsFour signature-related genes could relatively precisely predict the prognosis of patients with PDAC. Specifically, DDX21 upregulation may signal an unfavorable prognosis by negatively affecting the biological properties of PDAC cells. DDX21 may be considered as a candidate therapeutic target in PDAC.

Plumbagin's Antiproliferative Mechanism in Human Cancer Cells: A Copper-Dependent Cytotoxic Approach.

Cancer is a serious global health problem, causing the loss of millions of lives each year. Plumbagin, a compound derived from the medicinal plant Plumbago zeylanica, has shown promise in stopping the growth of tumor cells both in laboratory settings and in living organisms. Many plant-based compounds exert their effects through copper's ability to produce reactive oxygen species (ROS). This study aimed to understand how plumbagin, dependent on copper, induces cell death (apoptosis) in human cancer cells through various experiments. The results demonstrate that plumbagin hinders the growth of pancreatic cancer cells PNAC-1 and MIA PaCa-2 by utilizing the copper naturally present in the cells. Unlike metal chelators that remove iron and zinc (desferrioxamine mesylate and histidine), a specific copper chelator called neocuproine lessens the cell death caused by plumbagin. When ROS scavengers are used, plumbagin-induced apoptosis is inhibited, indicating that ROS plays a role in initiating cell death. The study also proves that plumbagin prevents copper from leaving cancer cells by suppressing the expression of specific genes (CTR1 and ATP7A). It is confirmed that plumbagin targets the nuclear copper, leading to signals that promote oxidative stress and, ultimately, cell death. These findings provide valuable insights into the potential of plumbagin as a substance to combat cancer, highlighting the importance of understanding how copper behaves within cancer cells.

Exosome Transfer Between Different Co-implanted Human Pancreatic Cancer Cell Lines Occurs in the Primary Tumor and Multiple Metastatic Sites of Nude Mice But Not in Co-Culture In Vitro.

Exosome exchange between cancer cells or between cancer and stromal cells is involved in cancer metastasis. We have previously developed in vivo color-coded labeling of cancer cells and stromal cells with spectrally-distinct fluorescent genetic reporters to demonstrate the role of exosomes in metastasis. In the present study, we studied exosome transfer between different pancreatic-cancer cell lines in vivo and in vitro and its potential role in metastasis. Human pancreatic-cancer cell lines AsPC-1 and MiaPaCa-2 were used in the present study. AsPC-1 cells contain a genetic exosome reporter gene labeled with green fluorescent protein (pCT-CD63-GFP) and MiaPaCa-2 cells express red fluorescent protein (RFP). Both cell lines were co-injected into the spleen of nude mice (n=5) to further study the role of exosome exchange in metastasis. Three weeks later mice were sacrificed and tumors at the primary and metastatic sites were cultured and observed by confocal fluorescence microscopy for exosome transfer. The primary tumor formed in the spleen and metastasized to the liver, as observed macroscopically. Cells were cultured from the spleen, liver, lung, bone marrow and ascites. Transfer of exosomes from AsPC-1 to MiaPaCa-2 was demonstrated in the cultured cells by confocal fluorescence microscopy. Moreover, cell fusion was also observed along with exosome transfer. Exosome transfer did not occur during in vitro co-culture between the two pancreatic-cancer cell lines, suggesting a role of the tumor microenvironment (TME) in exosome transfer. The transfer of exosomes between different pancreatic-cancer cell lines was observed during primary-tumor and metastatic growth in nude mice. This cell-cell communication might be a trigger of cell fusion and promotion of cancer metastasis. Exosome transfer between the two pancreatic-cancer cell lines appears to be facilitated by the TME, as it did not occur during in vitro co-culture.

New Analogues of the Nicotinamide Phosphoribosyltransferase Inhibitor FK866 as Potential Anti-Pancreatic Cancer Agents.

During the past two decades, many nicotinamide phosphoribosyltransferase (NAMPT) inhibitors were prepared and tested because this enzyme is overexpressed in pancreatic cancer. Although FK866 is a well-known, strong NAMPT inhibitor, it suffers severe drawbacks. Our work aimed to synthesize efficient NAMPT inhibitors featuring better pharmacokinetic properties than the pyridine-containing FK866. To this aim, the new anticancer agents were based on benzene, pyridazine, or benzothiazole moieties as a cap group instead of the pyridine unit found in FK866 and other NAMPT inhibitors. The new compounds, prepared exploiting standard heterocycle chemistry and coupling reactions (e.g., formation of amides, ureas, and cyanoguanidines, copper-mediated azide-alkyne cycloaddition), have been fully characterized using NMR and HRMS analyses. Their activity has been evaluated using cytotoxicity and intracellular NAD depletion assays in the human pancreatic cancer cell line MiaPaCa-2. Among the 14 products obtained, compound 28, bearing a pyridazine unit as the cap group and a thiophene moiety as the tail group, showed 6.7 nanomolar inhibition activity in the intracellular NAD depletion assay and 43 nanomolar inhibition in the MiaPaCa-2 cells cytotoxicity assay, comparable to that observed for FK866. The positive results observed for some newly synthesized molecules, particularly those carrying a thiophene unit as a tail group, indicate that they could act as in vivo anti-pancreatic cancer agents.

Role of Mitochondrial and Cytosolic Folylpolyglutamate Synthetase in One-Carbon Metabolism and Antitumor Efficacy of Mitochondrial-Targeted Antifolates.

Folate-dependent one-carbon (C1) metabolism encompasses distinct cytosolic and mitochondrial pathways connected by an interchange among serine, glycine, and formate. In both the cytosol and mitochondria, folates exist as polyglutamates, with polyglutamylation catalyzed by folylpolyglutamate synthetase (FPGS), including cytosolic and mitochondrial isoforms. Serine is metabolized by serine hydroxymethyltransferase (SHMT)2 in the mitochondria and generates glycine and C1 units for cellular biosynthesis in the cytosol. AGF347 is a novel pyrrolo[3,2-day]pyrimidine antifolate that targets SHMT2 in the mitochondria and SHMT1 and de novo purine biosynthesis in the cytosol. FPGS is expressed in primary pancreatic cancer specimens, and FPGS levels correlate with in vitro efficacies of AGF347 toward human pancreatic cancer cells. MIA PaCa-2 pancreatic cancer cells with CRISPR knockout of FPGS were engineered to express doxycycline-inducible FPGS exclusively in the cytosol (cFPGS) or in both the cytosol and mitochondria (mFPGS). Folate and AGF347 accumulations increased in both the cytosol and mitochondria with increased mFPGS but were restricted to the cytosol with cFPGS. AGF347-Glu5 inhibited SHMT2 ∼19-fold greater than AGF347 By metabolomics analysis, mFPGS stimulated the C1 flux from serine in the mitochondria and de novo purine and dTTP synthesis far greater than cFPGS. mFPGS enhanced in vitro inhibition of MIA PaCa-2 cell proliferation by AGF347 (∼30-fold) more than cFPGS (∼4.9-fold). Similar results were seen with other pyrrolo[3,2-d]pyrimidine antifolates (AGF291, AGF320); however, elevated mFPGS adversely impacted inhibition by the nonclassical SHMT2/SHMT1 inhibitor SHIN1. These results suggest a critical role of mFPGS levels in determining antitumor efficacies of mitochondrial-targeted pyrrolo[3,2-d]pyrimidine antifolates for pancreatic cancer. SIGNIFICANCE STATEMENT: AGF347 is a novel pyrrolo[3,2-d]pyrimidine antifolate that targets serine hydroxymethyltransferase (SHMT)2 in the mitochondria and SHMT1 and de novo purine biosynthesis in the cytosol. AGF347 accumulation increases with folylpolyglutamate synthetase (FPGS) levels in both the cytosol and mitochondria. Increased mitochondrial FPGS stimulated one-carbon metabolic fluxes in the cytosol and mitochondria and substantially enhanced in vitro inhibition of pancreatic cancer cells by AGF347. Mitochondrial FPGS levels play important roles in determining the antitumor efficacies of pyrrolo[3,2-d]pyrimidine antifolates for pancreatic cancer.

Design, synthesis and evaluation of new methyl piperazine derivatives as anticancer agents

BackgroundTo overcome the problem of side effects and toxicity, development of new anticancer agents is needed. Recently, piperidine salicylanilide derivatives with nanomolar epidermal growth factor receptor (EGFR) inhibitory and cytotoxicity activity have been reported. In the present study effect of replacing piperidine in reported piperidine salicylanilide with N-methyl piperazine and changing substituent’s of phenyl ring at other end on anticancer activity have been explored. A series of sixteen methyl piperazine incorporated phenyl benzamide and phenyl methanone derivatives have been synthesized and tested in a panel of three cancer cell lines (adenocarcinomic human alveolar basal epithelial cells (A-549), human colon carcinoma (HCT-116) and human pancreatic carcinoma (MIAPaCa-2)), using gefitinib as standard. Further, to study the probable mechanism, due to their structural similarity with EGFR inhibitors, docking interactions with EGFR active site were observed using Schrodinger suite.ResultThe results indicated that most of the compounds showed promising activity; out of which, compound A-11 was most active having cytotoxicity much better than that of gefitinib. It showed IC50 value of 5.71 µM against A-549 cell line, 4.26 µM against HCT-116 colon cancer line and 31.36 µM against MIAPaCa-2 cell line.ConclusionIt was found that these compounds fit well in the active site and may be exhibiting anticancer activity via EGFR inhibition.Graphical

Pharmacologic ascorbate induces transient hypoxia sensitizing pancreatic ductal adenocarcinoma to a hypoxia activated prodrug

Hypoxic tumor microenvironments pose a significant challenge in cancer treatment. Hypoxia-activated prodrugs like evofosfamide aim to specifically target and eliminate these resistant cells. However, their effectiveness is often limited by reoxygenation after cell death. We hypothesized that ascorbate's pro-oxidant properties could be harnessed to induce transient hypoxia, enhancing the efficacy of evofosfamide by overcoming reoxygenation.To test this hypothesis, we investigated the sensitivity of MIA Paca-2 and A549 cancer cells to ascorbate in vitro and in vivo. Ascorbate induced a cytotoxic effect at 5 mM that could be alleviated by endogenous administration of catalase, suggesting a role for hydrogen peroxide in its cytotoxic mechanism. In vitro, Seahorse experiments indicated that the generation of hydrogen peroxide consumes oxygen, which is offset at later time points by a reduction in oxygen consumption due to hydrogen peroxide's cytotoxic effect.In vivo, photoacoustic imaging showed pharmacologic ascorbate treatment at sublethal levels triggered a complex, multi-phasic response in tumor oxygenation across both cell lines. Initially, ascorbate generated transient hypoxia within minutes through hydrogen peroxide production, via reactions that consume oxygen. This initial hypoxic phase peaked at around 150 s and then gradually subsided. However, at longer time scales (approximately 300 s) a vasodilation effect triggered by ascorbate resulted in increased blood flow and subsequent reoxygenation. Combining sublethal levels of i. p. Ascorbate with evofosfamide significantly prolonged tumor doubling time in MIA Paca-2 and A549 xenografts compared to either treatment alone. This improvement, however, was only observed in a subpopulation of tumors, highlighting the complexity of the oxygenation response.

Andrographolide suppresses the malignancy of pancreatic cancer via alleviating DNMT3B-dependent repression of tumor suppressor gene ZNF382

BackgroundPancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer type that urgently requires effective therapeutic strategies. Andrographolide, a labdane diterpenoid compound abundant in Andrographis paniculata, has anticancer effects against various cancer types, but its anticancer activity and mechanism against PDAC remain largely uncharacterized. PurposeThis study explores novel drug target(s) and underlying molecular mechanism of andrographolide against PDAC. Study design and methodsThe malignant phenotypes of PDAC cells, PANC-1 and MIA PaCa-2 cells, were measured using MTT, clonogenic assays, and Transwell migration assays. A PDAC xenograft animal model was used to evaluate tumor growth in vivo. Western blot, immunofluorescence and immunohistochemistry were used for measuring protein expression. The TCGA database was analyzed to evaluate promoter methylation status, gene expression, and their relationship with patient survival rates. RT-qPCR was used for detecting mRNA expression. Reporter assays were used for detecting signal transduction pathways. Promoter DNA methylation was determined by sodium bisulfite treatment and methylation-specific PCR (MSP). The biological function and role of specific genes involved in drug effects were measured through gene overexpression. ResultsAndrographolide treatment suppressed the proliferation and migration of PDAC cells and impaired tumor growth in vivo. Furthermore, andrographolide induced the mRNA and protein expression of zinc finger protein 382 (ZNF382) in PDAC cells. Overexpression of ZNF382 inhibited malignant phenotypes and cancer-associated signaling pathways (AP-1, NF-κB and β-catenin) and oncogenes (ZEB-1, STAT-3, STAT-5, and HIF-1α). Overexpression of ZNF382 delayed growth of PANC-1 cells in vivo. ZNF382 mRNA and protein expression was lower in tumor tissues than in adjacent normal tissues of pancreatic cancer patients. Analysis of the TCGA database found the ZNF382 promoter is hypermethylated in primary pancreatic tumors which correlates with its low expression. Furthermore, andrographolide inhibited the expression of DNA methyltransferase 3 beta (DNMT3B) and increased the demethylation of the ZNF382 promoter in PDAC cells. Overexpression of DNMT3B attenuated the andrographolide-suppressed proliferation and migration of PDAC cells. ConclusionOur finding revealed that ZNF382 acts as a tumor suppressor gene in pancreatic cancer and andrographolide restores ZNF382 expression to suppress pancreatic cancer, providing a novel molecular target and a promising therapeutic approach for treating pancreatic cancer.

Brucine Inhibits Proliferation of Pancreatic Ductal Adenocarcinoma through PI3K/AKT Pathway-induced Mitochondrial Apoptosis.

The purpose of this research was to settle the role of brucine in pancreatic ductal adenocarcinoma (PDAC) and the mechanisms involved. The findings of this study suggest that brucine exerts inhibitory effects on cell growth, clonogenicity, and invasive potential of Panc02 and Mia Paca-2 cells. These effects may be linked to an increase in apoptotic-prone cell population. Gene sequencing data suggests that these effects are mediated through the induction of apoptosis. Experimental evidence further supports the notion that brucine reduces mitochondrial membrane potential and upregulates Bax expression while downregulating Bcl-2 expression. These effects are believed to be a result of brucine-mediated suppression of PI3K/Akt activity, which serves as a regulatory factor of mTOR, Bax, and Bcl-2. Suppression of PI3K activity enhances the tumor-suppressing effects of brucine. Overall, these findings suggest that brucine has therapeutic potential as a remedy option for PDAC.

Ultrasound-stimulated Microbubbles for Treatment of Pancreatic Cancer Cells with Radiation and Nanoparticles: In vitro Study

Purpose: This study aims to investigate the radiation enhancement effects of ultrasound-stimulated microbubbles (USMB) with X-rays and nanoparticles on pancreatic cancer cells in vitro. Methods: Sonazoid™ microbubbles were used for USMB treatment with a commercially available ultrasound unit. The characterization of the microbubbles before and after ultrasound exposure with different mechanical parameters was evaluated microscopically. Two pancreatic cancer cell lines, MIAPaCa-2 and PANC-1, were treated with different concentrations of microbubbles in combination with 150 kVp X-rays and hydrogen peroxide-modified titanium dioxide nanoparticles. Cell viability was evaluated using a water-soluble tetrazolium dye and a colony formation assay. In addition, intracellular reactive oxygen species (ROS) induced by the combined treatment were assessed. Results: The number of burst microbubbles increased with ultrasound’s higher mechanical index and the exposure time. A significant radiation enhancement effect with a significant increase in ROS levels was observed in MIAPaCa-2 cells treated with USMB and 6 Gy X-rays, whereas it was not significant in PANC-1 cells treated with the same. When a higher concentration of USMB was applied with X-rays, no radiation enhancement effects were observed in either cell line. Moreover, there was no radiation enhancement effect by USMB between cells treated with and without nanoparticles. Conclusions: The results indicate that USMB treatment can additively enhance the therapeutic efficacy of radiation therapy on pancreatic cancer cells, while the synergistic enhancement effects are likely to be cell type and microbubble concentration dependent. In addition, USMB did not improve the efficacy of nanoparticle-induced radiosensitization in the current setting.

Design and synthesis of new nicotinamide derivatives generated via Suzuki Miyaura coupling as potential anticancer hits targeting pancreatic cancer cell line MIA PaCa-2

Pancreatic cancer is one of the most fatal malignancies with low survival rate and spreads asymptomatically due to the intensive involvement and expression of PARP1 protein. Nicotinamide is recognised as an efficient ring system in the treatment of pancreatic cancer because of its uses in both cellular and biological processes. In this investigation, 3-methoxyphenyl nicotinamide derivatives were synthesised utilizing a palladium-catalysed Suzuki-Miyaura coupling, and their confirmation has been identified by spectroscopic techniques (HRMS, 1H NMR & 13C NMR). The confirmed compounds (5a-f) were introduced to in-vitro cytotoxic studies using the MTT assay, which demonstrated that 5d and 5f were potent against MIA PaCa-2 cell line with IC50 values of 26±1.21µM and 18.61±0.20µM. The compounds 5d and 5f were also examined against HEK 293 cells, which exhibited a diminished antiproliferative effect with an IC50 values of 82.6µM and 138.07µM, respectively. Consequently, 5d and 5f were found to be safer with reduced antiproliferative effect. The MTT assay results were validated by the molecular docking and ADMET studies, which revealed the binding affinities of compounds 5d and 5f are -9.1 and -9.4 Kcal/mol. Overall, the designed and synthesised conjugates 5d and 5f demonstrated a viable lead for the investigation of new chemotherapeutic drugs against pancreatic cancer in this study.

MEK inhibitors and DA-Raf, a dominant-negative antagonist of the Ras-ERK pathway, prevent the migration and invasion of KRAS-mutant cancer cells.

The Ras-induced ERK pathway (Raf-MEK-ERK signaling cascade) regulates a variety of cellular responses including cell proliferation, survival, and migration. Activating mutations in RAS genes, particularly in the KRAS gene, constitutively activate the ERK pathway, resulting in tumorigenesis, cancer cell invasion, and metastasis. DA-Raf1 (DA-Raf) is a splicing isoform of A-Raf and contains the Ras-binding domain but lacks the kinase domain. Consequently, DA-Raf antagonizes the Ras-ERK pathway in a dominant-negative manner and can serve as a tumor suppressor that targets mutant Ras protein-induced tumorigenesis. We show here that MEK inhibitors and DA-Raf interfere with the in vitro collective cell migration and invasion of human KRAS-mutant carcinoma cell lines, the lung adenocarcinoma A549, colorectal carcinoma HCT116, and pancreatic carcinoma MIA PaCa-2 cells. DA-Raf expression was silenced in these cancer cell lines. All these cell lines had high collective migration abilities and invasion properties in Matrigel, compared with nontumor cells. Their migration and invasion abilities were impaired by suppressing the ERK pathway with the MEK inhibitors U0126 and trametinib, an approved anticancer drug. Expression of DA-Raf in MIA PaCa-2 cells reduced the ERK activity and hindered the migration and invasion abilities. Therefore, DA-Raf may function as an invasion suppressor protein in the KRAS-mutant cancer cells by blocking the Ras-ERK pathway when DA-Raf expression is induced in invasive cancer cells.

Identification of a novel GSK3β inhibitor involved in abrogating KRas dependent pancreatic tumors in Wnt/beta-catenin and NF-kB dependent manner

Pancreatic cancer is an aggressive malignancy with a poor survival rate because it is difficult to diagnose the disease during its early stages. The currently available treatments, which include surgery, chemotherapy and radiation therapy, offer only limited survival benefit. Pharmacological interventions to inhibit Glycogen Synthase Kinase-3beta (GSK3β) activity is an important therapeutic strategy for the treatment of pancreatic cancer because GSK3β is one of the key factors involved in the onset, progression as well as in the acquisition of chemoresistance in pancreatic cancer. Here, we report the identification of MJ34 as a potent GSK3β inhibitor that significantly reduced growth and survival of human mutant KRas dependent pancreatic tumors. MJ34 mediated GSK3β inhibition was seen to induce apoptosis in a β-catenin dependent manner and downregulate NF-kB activity in MiaPaCa-2 cells thereby impeding cell survival and anti-apoptotic processes in these cells as well as in the xenograft model of pancreatic cancer. In vivo acute toxicity and in vitro cardiotoxicity studies indicate that MJ34 is well tolerated without any adverse effects. Taken together, we report the discovery of MJ34 as a potential drug candidate for the therapeutic treatment of mutant KRas-dependent human cancers through pharmacological inhibition of GSK3β.

Conofolidine: A Natural Plant Alkaloid That Causes Apoptosis and Senescence in Cancer Cells.

Natural products contribute substantially to anticancer therapy; the plant kingdom provides an important source of molecules. Conofolidine is a novel Aspidosperma-Aspidosperma bisindole alkaloid isolated from the Malayan plant Tabernaemontana corymbosa. Herein, we report conofolidine's broad-spectrum anticancer activity together with that of three other bisindoles-conophylline, leucophyllidine, and bipleiophylline-against human-derived breast, colorectal, pancreatic, and lung carcinoma cell lines. Remarkably, conofolidine was able to induce apoptosis (e.g., in MDA-MB-468 breast) or senescence (e.g., in HT-29 colorectal) in cancer cells. Annexin V-FITC/PI, caspase activation, and PARP cleavage confirmed the former while positive β-gal staining corroborated the latter. Cell cycle perturbations were evident, comprising S-phase depletion, accompanied by downregulated CDK2, and cyclins (A2, D1) with p21 upregulation. Confocal imaging of HCT-116 cells revealed an induction of aberrant mitotic phenotypes-membrane blebbing, DNA-fragmentation with occasional multi-nucleation. DNA integrity assessment in HCT-116, MDA-MB-468, MIAPaCa-2, and HT-29 cells showed increased fluorescent γ-H2AX during the G1 cell cycle phase; γ-H2AX foci were validated in HCT-116 and MDA-MB-468 cells by confocal microscopy. Conofolidine increased oxidative stress, preceding apoptosis- and senescence-induction in most carcinoma cell lines as seen by enhanced ROS levels accompanied by increased NQO1 expression. Collectively, we present conofolidine as a putative potent anticancer agent capable of inducing heterogeneous modes of cancerous cell death in vitro, encouraging further preclinical evaluations of this natural product.

Exploring the Molecular Therapeutic Mechanisms of Gemcitabine through Quantitative Proteomics.

Gemcitabine (GEM) is widely employed in the treatment of various cancers, including pancreatic cancer. Despite their clinical success, challenges related to GEM resistance and toxicity persist. Therefore, a deeper understanding of its intracellular mechanisms and potential targets is urgently needed. In this study, through mass spectrometry analysis in data-dependent acquisition mode, we carried out quantitative proteomics (three independent replications) and thermal proteome profiling (TPP, two independent replications) on MIA PaCa-2 cells to explore the effects of GEM. Our proteomic analysis revealed that GEM led to the upregulation of the cell cycle and DNA replication proteins. Notably, we observed the upregulation of S-phase kinase-associated protein 2 (SKP2), a cell cycle and chemoresistance regulator. Combining SKP2 inhibition with GEM showed synergistic effects, suggesting SKP2 as a potential target for enhancing the GEM sensitivity. Through TPP, we pinpointed four potential GEM binding targets implicated in tumor development, including in breast and liver cancers, underscoring GEM's broad-spectrum antitumor capabilities. These findings provide valuable insights into GEM's molecular mechanisms and offer potential targets for improving treatment efficacy.

Lysophosphatidylcholine acyltransferase 1 suppresses nanoclustering and function of KRAS.

KRAS is frequently mutated in cancer, contributing to 20% of all human cancer especially pancreatic, colorectal and lung cancer. Signaling of the constitutively active KRAS oncogenic mutants is mostly compartmentalized to proteolipid nanoclusters on the plasma membrane (PM). Signaling nanoclusters of many KRAS mutants selectively enrich phosphatidylserine (PS) lipids with unsaturated sn-2 acyl chains, but not the fully saturated PS species. Thus, remodeling PS acyl chains may suppress KRAS oncogenesis. Lysophosphatidylcholine acyltransferases (LPCATs) remodel sn-2 acyl chains of phospholipids, with LPCAT1 preferentially generating the fully saturated lipids. Here, we show that stable expression of LPCAT1 depletes major PS species with unsaturated sn-2 chains while decreasing minor phosphatidylcholine (PC) species with the corresponding acyl chains. LPCAT1 expression more effectively disrupts the nanoclustering of oncogenic GFP-KRASG12V, which is restored by acute addback of exogenous unsaturated PS. LPCAT1 expression compromises signaling and oncogenic activities of the KRAS-dependent pancreatic tumor lines. LPCAT1 expression sensitizes human pancreatic tumor MiaPaCa-2 cells to KRASG12C specific inhibitor, Sotorasib. Statistical analyses of patient data further reveal that pancreatic cancer patients with KRAS mutations express less LPCAT1. Higher LPCAT1 expression also improves survival probability of pancreatic and lung adenocarcinoma patients with KRAS mutations. Thus, PS acyl chain remodeling selectively suppresses KRAS oncogenesis.