Pancreatic Cancer Cell Lines BxPC-3 Research Articles

Unraveling the hepatoprotective and anti-pancreatic cancer potential of Caralluma europaea: a comprehensive in vivo, in vitro and in silico evidence

Caralluma europaea Guss. (C. europaea) is a medicinal plant used for cancer treatment. However, these treatments may be associated with complications that need to be investigated. This work aims to evaluate not only the chemical composition but also the hepatoprotective and anticancer properties of C. europaea extracts. The chemical constitution of the hydroethanolic extract was explored using gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). The hydroethanolic extract, flavonoids, and polyphenols-rich extract at 100, 15, and 50 mg/kg, respectively, were administered to acetaminophen-treated rats for seven days. We used Western blotting and Real-Time quantitative Polymerase Chain Reaction (RT-qPCR) to determine the protein and the mRNA levels of cancer stemness markers in pancreatic cancer cell lines MIA PaCa-2 and BxPC-3 exposed to increasing doses of C. europaea extracts. In silico analysis was used to evaluate the effects of phenolic compounds revealed in C. europaea on caspase-3 and HSP90, and on liver damage on CYP2E1. The primary phenolics detected by GC-MS and HPLC were ferulic acid and benzofurazan. The positive control group showed an increase in AST, ALT, ALP, triglycerides, and VLDL levels. C. europaea extracts demonstrated hepatoprotective effects by ameliorating acetaminophen-induced alterations of biochemical and hispathological parameters. Immunoblotting and RT-qPCR profiling of cancer stemness markers indicated a reduction in the expression levels of Oct-4 and Nanog proteins, as well as a reduction in the mRNA levels of CD133 by 50–60% and Sox2 by 80–90% in pancreatic cancer cells. Molecular docking showed that naringenin presented the highest docking Gscore on CYP2E1 (−8.199) and HSP90 (−7.742). In conclusion, C. europaea extracts could be considered as a safe and promising therapeutic strategy to sensitize pancreatic cancer cells to chemotherapy.

Combination of S-1 and the oral ATR inhibitor ceralasertib is effective against pancreatic cancer cells.

In our previous study, we found that the Chk1 inhibitor prexasertib enhances the antitumour effect of the oral anticancer drug S-1 against pancreatic cancer cells. In this study, we investigated the effect of combining S-1 and ceralasertib, an oral inhibitor of ATR, which is located upstream of Chk1. Ceralasertib is currently being investigated in multiple clinical trials for various cancers. The cell-proliferation inhibitory effect was measured by MTT assay, using the pancreatic cancer cell lines BxPC-3, SUIT-2, PANC-1, and MIA PaCa-2, while apoptosis was measured by flow cytometry using PI/Annexin staining. The mechanism underlying the combined effect was analysed using western blotting, and the antitumor effect was analysed using a mouse xenograft model. MTT assay revealed that the combination of S-1 and ceralasertib had a synergistic effect, leading to the suppression of cell proliferation. Measurement with PI/Annexin staining revealed that the combination of S-1 and ceralasertib induced apoptosis more efficiently than either drug alone. Western blotting results showed that ceralasertib inhibited S-1-induced activation of ATR and Chk1. The average estimated tumour volume after 3weeks of administration was 601 mm3 in the S-1 group, 580 mm3 in the ceralasertib group, and 298 mm3 in the combination group. The combination of S-1 and ceralasertib demonstrated a high antiproliferative effect in inhibiting tumour growth in vitro.

Bioinformatical and experimental validation on EFNA5 biomarker for pancreatic cancer

Pancreatic cancer is one of the most aggressive malignancies in the digestive system, characterized by vague early symptoms and rapid disease progression. Currently, treatment options for pancreatic cancer are limited, with unsatisfactory outcomes and poor prognosis, as the overall 5-year survival rate is less than 10%. Therefore, it is crucial to identify new biomarkers for pancreatic cancer.We analyzed the differential expression of EFNA5 at the mRNA level using data from the TCGA, GTEX, and GEO databases, followed by validation of EFNA5 protein expression differences through immunohistochemistry. Kaplan-Meier survival analysis and Cox regression analysis were used to explore the prognostic value of EFNA5. KEGG, GO enrichment analyses, and GSEA were employed to predict the biological functions of EFNA5. Bioinformatics algorithms were utilized to analyze the impact of EFNA5 on drug sensitivity, immune cell infiltration, and tumor mutational burden. Finally, we conducted cell phenotype experiments to investigate the effects of EFNA5 on the proliferation, migration, and invasion of pancreatic cancer cells. Bioinformatics data showed that the mRNA level of EFNA5 was higher in pancreatic cancer tissues compared to normal tissues. Immunohistochemistry experiments confirmed that the protein expression level of EFNA5 was significantly higher in pancreatic cancer tissues (n = 19) than in adjacent normal tissues (n = 19). Survival analysis indicated that the overall survival (OS) and progression-free survival (PFS) were worse in the high EFNA5 expression group compared to the low expression group. Univariate and multivariate Cox regression analyses demonstrated that EFNA5 is a risk factor affecting the prognosis of pancreatic cancer patients. KEGG pathway enrichment analysis revealed that differentially expressed genes (DEGs) between high and low EFNA5 expression groups were primarily enriched in pathways such as PI3K/Akt, axon guidance, and focal adhesion. GO enrichment analysis showed that DEGs were mainly associated with functions like epidermis development, cell adhesion, and intercellular junctions. Immune cell infiltration analysis found that EFNA5 expression was correlated with the infiltration levels of various immune cells. The tumor mutational burden was higher in the high EFNA5 expression group compared to the low expression group. Drug sensitivity analysis indicated that the high EFNA5 expression group had lower sensitivity to several commonly used chemotherapy drugs for pancreatic cancer. Cellular experiments demonstrated that knocking down EFNA5 inhibited the proliferation, invasion, and migration of pancreatic cancer cells. EFNA5 is overexpressed in pancreatic cancer tissues, and its high expression is associated with poor prognosis in pancreatic cancer patients. Downregulation of EFNA5 reduces the proliferation, migration, and invasion capabilities of the pancreatic cancer cell line BxPC-3. EFNA5 is closely related to the occurrence, development, prognosis, immune infiltration, and drug sensitivity of pancreatic cancer. Our study suggests that EFNA5 is a potential biomarker and therapeutic target.

Synthesis and antiproliferative activity of CBD aromatic ester derivatives

This study involved the synthesis of a series of novel cannabidiol (CBD) aromatic ester derivatives, including CBD-8,12-diaromaticester derivatives (compounds 2a–2t) and CBD-8,12-diacetyl-21-aromaticester derivatives (compound 5a–5c). The antiproliferative activities of these compounds against human liver cancer cell lines HePG2 and HeP3B as well as human pancreatic cancer cell lines ASPC-1 and BXPC-3 were evaluated in vitro using the CCK-8 assay. The results indicated that compound 2f exhibited an IC50 value of 2.75 µM against HePG2, which is 5.32-fold higher than that of CBD. Additionally, compounds 2b and 5b demonstrated varying degrees of improved anticancer activity (IC50 5.95-9.21 µM) against HePG2.

Synergistic cytotoxicity of histone deacetylase and poly-ADP ribose polymerase inhibitors and decitabine in pancreatic cancer cells: Implications for novel therapy.

Histone deacetylase inhibitors (HDACi) can modulate the acetylation status of proteins, influencing the genomic instability exhibited by cancer cells. Poly (ADP ribose) polymerase (PARP) inhibitors (PARPi) have a direct effect on protein poly (ADP-ribosyl)ation, which is important for DNA repair. Decitabine is a nucleoside cytidine analogue, which when phosphorylated gets incorporated into the growing DNA strand, inhibiting methylation and inducing DNA damage by inactivating and trapping DNA methyltransferase on the DNA, thereby activating transcriptionally silenced DNA loci. We explored various combinations of HDACi and PARPi +/- decitabine (hypomethylating agent) in pancreatic cancer cell lines BxPC-3 and PL45 (wild-type BRCA1 and BRCA2) and Capan-1 (mutated BRCA2). The combination of HDACi (panobinostat or vorinostat) with PARPi (talazoparib or olaparib) resulted in synergistic cytotoxicity in all cell lines tested. The addition of decitabine further increased the synergistic cytotoxicity noted with HDACi and PARPi, triggering apoptosis (evidenced by increased cleavage of caspase 3 and PARP1). The 3-drug combination treatments (vorinostat, talazoparib, and decitabine; vorinostat, olaparib, and decitabine; panobinostat, talazoparib, and decitabine; panobinostat, olaparib, and decitabine) induced more DNA damage (increased phosphorylation of histone 2AX) than the individual drugs and impaired the DNA repair pathways (decreased levels of ATM, BRCA1, and ATRX proteins). The 3-drug combinations also altered the epigenetic regulation of gene expression (NuRD complex subunits, reduced levels). This is the first study to demonstrate synergistic interactions between the aforementioned agents in pancreatic cancer cell lines and provides preclinical data to design individualized therapeutic approaches with the potential to improve pancreatic cancer treatment outcomes.

Evaluation of Helium Ion Radiotherapy in Combination with Gemcitabine in Pancreatic Cancer In Vitro.

Pancreatic cancer is one of the most aggressive and lethal cancers. New treatment strategies are highly warranted. Particle radiotherapy could offer a way to overcome the radioresistant nature of pancreatic cancer because of its biological and physical characteristics. Within particles, helium ions represent an attractive therapy option to achieve the highest possible conformity while at the same time protecting the surrounding normal tissue. The aim of this study was to evaluate the cytotoxic efficacy of helium ion irradiation in pancreatic cancer in vitro. Human pancreatic cancer cell lines AsPC-1, BxPC-3 and Panc-1 were irradiated with photons and helium ions at various doses and treated with gemcitabine. Photon irradiation was performed with a biological cabin X-ray irradiator, and helium ion irradiation was performed with a spread-out Bragg peak using the raster scanning technique at the Heidelberg Ion Beam Therapy Center (HIT). The cytotoxic effect on pancreatic cancer cells was measured with clonogenic survival. The survival curves were compared to the predicted curves that were calculated via the modified microdosimetric kinetic model (mMKM). The experimental relative biological effectiveness (RBE) of helium ion irradiation ranged from 1.0 to 1.7. The predicted survival curves obtained via mMKM calculations matched the experimental survival curves. Mainly additive cytotoxic effects were observed for the cell lines AsPC-1, BxPC-3 and Panc-1. Our results demonstrate the cytotoxic efficacy of helium ion radiotherapy in pancreatic cancer in vitro as well as the capability of mMKM calculation and its value for biological plan optimization in helium ion therapy for pancreatic cancer. A combined treatment of helium irradiation and chemotherapy with gemcitabine leads to mainly additive cytotoxic effects in pancreatic cancer cell lines. The data generated in this study may serve as the radiobiological basis for future experimental and clinical works using helium ion radiotherapy in pancreatic cancer treatment.

Abstract LB158: Synergistic cytotoxicity of histone deacetylase and poly-ADP ribose polymerase inhibitors and decitabine in pancreatic cancer cells: implications for novel therapy

Abstract Histone deacetylase inhibitors (HDACi) can modulate the acetylation status of proteins, influencing the genomic instability exhibited by cancer cells. Poly (ADP ribose) polymerase (PARP) inhibitors (PARPi) have a direct effect on protein poly (ADP-ribosyl)ation, which is important for DNA repair. Decitabine is a nucleoside cytidine analogue, which when phosphorylated gets incorporated into the growing DNA strand, inhibiting methylation and inducing DNA damage by inactivating and trapping DNA methyltransferase on the DNA, thereby activating transcriptionally silenced DNA loci. We explored various combinations of HDACi and PARPi +/- decitabine (hypomethylating agent) in pancreatic cancer cell lines BxPC-3 and PL45 (wild-type BRCA1 and BRCA2) and Capan-1 (mutated BRCA2). Colony formation and drug-mediated inhibition of cell proliferation in pancreatic cancer cell lines and comparison of the effects of each drug combination with the effect of the individual drugs are shown in Table. The combination of HDACi (panobinostat or vorinostat) with PARPi (talazoparib or olaparib) resulted in synergistic cytotoxicity in all cell lines tested. The addition of decitabine further increased the synergistic cytotoxicity noted with HDACi and PARPi, triggering apoptosis (evidenced by increased cleavage of caspase 3 and PARP1). The 3-drug combination treatments (vorinostat, talazoparib, and decitabine; vorinostat, olaparib, and decitabine; panobinostat, talazoparib, and decitabine; panobinostat, olaparib, and decitabine) induced more DNA damage (increased phosphorylation of histone 2AX) than the individual drugs and impaired the DNA repair pathways (decreased levels of ATM, BRCA1, and ATRX proteins). The 3-drug combinations also altered the epigenetic regulation of gene expression (NuRD complex subunits, reduced levels). This is the first study to demonstrate synergistic interactions between the aforementioned agents in pancreatic cancer cell lines and provides preclinical data to design individualized therapeutic approaches with the potential to improve pancreatic cancer treatment outcomes. Table. Colony formation and drug-mediated inhibition of cell proliferation in pancreatic cancer cell lines. Comparison of the effects of each drug combination with the effect of the individual drugs (Table shows the p-values for each comparison.) Colony formation BxPC-3 PL45 Capan-1 Pano SAHA TLZ Ola DAC Pano SAHA TLZ Ola DAC Pano SAHA TLZ Ola DAC Pano+TLZ 0.00048 0.0052 2.40E-06 2.70E-06 0.0051 0.021 Pano+Ola 0.0035 0.078 0.0011 0.00094 0.0016 0.022 SAHA+TLZ 1.80E-05 0.17 0.0029 0.012 0.0014 0.019 SAHA+Ola 0.00018 0.014 0.0016 0.0068 0.0066 0.029 Pano+TLZ+DAC 4.20E-05 0.00026 0.0015 1.70E-05 1.20E-05 2.70E-06 0.00052 0.00088 0.0064 Pano+Ola+DAC 3.40E-05 0.00049 0.0013 7.10E-07 1.70E-06 2.20E-06 0.00068 0.0028 0.0053 SAHA+TLZ+DAC 0.00016 0.00016 0.0011 1.90E-05 3.70E-06 9.30E-07 0.00018 0.00017 0.011 SAHA+Ola+DAC 4.90E-07 0.00035 0.001 0.00022 0.00026 0.00084 0.00016 0.0016 0.0035 Drug-mediated inhibition of cell proliferation Pano+TLZ+DAC 3.57E-05 3.89E-07 1.30E-07 2.91E-05 3.76E-06 1.80E-08 0.0239 ND 0.0092 Pano+Ola+DAC 7.76E-05 1.43E-07 2.52E-07 6.59E-07 1.03E-08 2.22E-07 0.0013 0.21 0.0034 SAHA+TLZ+DAC 3.04E-06 0.00034 1.17E-05 4.91E-08 4.45E-06 1.74E-07 0.0013 1.75E-01 0.007 SAHA+Ola+DAC 0.00012 0.0032 0.000068 9.64E-09 1.53E-08 9.35E-07 0.0007 0.18 0.0054 Abbreviations: DAC: decitabine; ND: not determined; Ola: olaparib; Pano: panobinostat; SAHA: vorinostat; TLZ: talazoparib P ≤ 0.05 is considered statistically significant. Citation Format: Apostolia M. Tsimberidou, Benigno C. Valdez, Bin Yuan, Yago Nieto, Mehmet Baysal, Abhijit Chakraborty, Borje S. Andersson. Synergistic cytotoxicity of histone deacetylase and poly-ADP ribose polymerase inhibitors and decitabine in pancreatic cancer cells: implications for novel therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB158.

Abstract 7291: Detection of a truncated form of multidrug resistance protein 1 (MRP1) in plasma sEVs derived from cancer patients

Abstract Multidrug resistance protein 1 (MRP1/ABCC1) is an ATP dependent transmembrane efflux pump that confers to drug resistance. Overexpression of MRP1 has been observed in both pancreatic ductal adenocarcinoma (PDAC) and breast cancer tissues. Numerous proteomics studies have revealed the presence of MRP1 in small extracellular vesicles (sEVs) released from cancer cells. Cancer-derived sEVs are known to be released into the circulation, thus becoming attractive candidates for non-invasive biomarker development. However, whether the MRP1 level in plasma sEVs is indicative of human cancer has not been evaluated. This study examined the MRP1 expression in plasma sEVs derived from patients with PDAC, breast and colon cancer, and age- and gender-matched healthy subjects. The patient plasma samples were obtained primarily from the NCI-sponsored Cooperative Human Tissue Network and Stephenson Cancer Center. Healthy plasma samples were provided by the Oklahoma Blood institute. Human pancreatic cancer cell lines PANC-1, MIA PaCa-2 and BxPC-3, and the pancreatic ductal cell line hTERT-HPNE were tested for MRP1 expression prior to examination of plasma samples. Cellular and plasma sEVs were isolated using the double filtration followed by polymer precipitation method. Western blot was performed to assess the expression level of MRP1 and proteomics was applied to confirm the detection of a truncated form of MRP1 in plasma sEVs. MRP1 expression was detected in the sEVs derived from all three pancreatic cancer cell lines but absent in the sEVs from the HPNE line. Overexpression of a truncated MRP1 protein was detected in plasma sEVs derived from patients with early stage (stage I-IIA) and late stage (III-IV) PDAC, compared with that from matched healthy subjects (n=17 for each group). Similar findings were evident in plasma sEVs from patients with breast cancer (n=7), while the results remained inconclusive in plasma sEVs from patients with colon cancer (n=7). Protein structure analysis indicated that the truncated form of MRP1 likely consists of the regions between the QCRL-1 motif and the C-terminus of the protein. Proteomic analysis detected the peptides derived from the C-terminus region, consistent with the structural analysis. Furthermore, the truncated form of MRP1 can only be detected using antibodies against the epitopes in the C-terminus and QCRL-1 region of MRP1 protein. In summary, we have detected a truncated form of MRP1 protein in plasma sEVs derived from cancer patients, and the level of its expression is significantly elevated in patients with PDAC and breast cancer. Citation Format: Kritisha Bhandari, Jeng Shi Kong, Chao Xu, Ajay Jain, Wei-Qun Ding. Detection of a truncated form of multidrug resistance protein 1 (MRP1) in plasma sEVs derived from cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7291.

Efficient Assessment of Tumor Vascular Shutdown by Photodynamic Therapy on Orthotopic Pancreatic Cancer Using High-Speed Wide-Field Waterproof Galvanometer Scanner Photoacoustic Microscopy.

To identify the vascular alteration by photodynamic therapy (PDT), the utilization of high-resolution, high-speed, and wide-field photoacoustic microscopy (PAM) has gained enormous interest. The rapid changes in vasculature during PDT treatment and monitoring of tumor tissue activation in the orthotopic pancreatic cancer model have received limited attention in previous studies. Here, a fully two-axes waterproof galvanometer scanner-based photoacoustic microscopy (WGS-PAM) system was developed for in vivo monitoring of dynamic variations in micro blood vessels due to PDT in an orthotopic pancreatic cancer mouse model. The photosensitizer (PS), Chlorin e6 (Ce6), was utilized to activate antitumor reactions in response to the irradiation of a 660 nm light source. Microvasculatures of angiogenesis tissue were visualized on a 40 mm2 area using the WGS-PAM system at 30 min intervals for 3 h after the PDT treatment. The decline in vascular intensity was observed at 24.5% along with a 32.4% reduction of the vascular density at 3 h post-PDT by the analysis of PAM images. The anti-vascularization effect was also identified with fluorescent imaging. Moreover, Ce6-PDT increased apoptotic and necrotic markers while decreasing vascular endothelial growth factor (VEGF) expression in MIA PaCa-2 and BxPC-3 pancreatic cancer cell lines. The approach of the WGS-PAM system shows the potential to investigate PDT effects on the mechanism of angiographic dynamics with high-resolution wide-field imaging modalities.

Juglone Effects by Dual Way on mTOR Gene Expression, Which Plays Central Role in Cell Growth, Survival and Metabolism, in PANC-1 and BxPC-3 Pancreatic Cancer Cell Lines

Background/Aims: Juglone, as a naphthoquinone, has been shown to have cytotoxic and apoptotic effects in various cancer cells and besides this effects it was reported to have anti-invasive and anti-metastatic effects in PANC-1 and BxPC-3 cells in our previous studies. In this study, we investigated the effects of juglone on GRP75, TFAM and mTOR genes encoding key proteins associated with mitochondrial biogenesis and activation in PANC-1 and BxPC-3 pancreatic cancer cells since mitochondria has central roles in cancer cell survival, metastasis and therapeutic resistance. Methods: In our study; 5, 10, 15 and 20 μM juglone doses were selected as the application doses considering the IC50 value determined after MTT test results and the expressions of the target genes were analyzed by qPCR method after application of juglone doses for 24 hours. Results: Our study results revealed that juglone had an opposite and strong effects on mTOR expression in both cell lines. Conclusion: Our findings suggest that juglone has a developable potential and is a promising theurapeutic agent to develop new strategies for the battle with cancer with those effects on mTOR gene which plays a central role in cellular homeostasis and several cellular events including cell growth, survival and metabolism.

Flavonoids as potential reactivators of structural mutation p53Y220C by computational and cell-based studies

The p53 Y220C is one of the most frequently observed structural mutants in various human cancers. The substitution of residue Tyr to Cys makes the p53 DNA binding domain susceptible to solvent entry into the hydrophobic core of the domain thereby destabilizing p53, which results in loss of its tumor suppressor activity. The mutation creates a structural crevice at the region between S3/S4 and S7/S8 loops in the DNA binding domain which can be targeted by small molecules. Studies have shown that the synthetic and natural compounds could bind to this crevice and restore the structure and function of the mutant p53Y220C to the wild type. In our previous study, we have shown Curcumin could rescue the function of mutant p53Y220C in pancreatic cancer cell line BxPC-3 harboring genomic mutation. In this study, we explored six flavonoids structurally similar to Curcumin such as Apigenin, Isoliquiritigenin, Liquiritigenin, Luteolin, Methylophiopogonanone A (MPA), and Methylophiopogonanone B (MPB) to test their potency to restore p53Y220C by molecular docking, molecular dynamics simulations and cytotoxicity assay. The secondary structure analysis after the MD simulations suggested that these compounds could stabilize the mutant p53 DNA binding domain to the wild type. In the cell-based cytotoxicity studies using p53Y220C harbouring BxPC-3 cell lines, the compounds MPA and MPB showed 75% cell death at 100 µM concentration. We proposed that the flavonoids MPA and MPB have the therapeutic potential to restore p53Y220C and could be used as a combinatorial therapy to reduce the dosage burden. Communicated by Ramaswamy H. Sarma

Betulinic acid, a major therapeutic triterpene of Celastrus orbiculatus Thunb., acts as a chemosensitizer of gemcitabine by promoting Chk1 degradation.

Celastrus orbiculatus Thunb., also called as oriental bittersweet vine or climbing spindle berry, a traditional Chinese herbal medicine has been used to treat a spectrum of painful and inflammatory diseases for centuries. Explored for their unique medicinal properties, C.orbiculatus offers additional therapeutic effects on cancerous diseases. The effect of single-agent gemcitabine on survival has not long been encouraging, combination therapies provide patients multiple chances of benefit for improved clinical response. This study aims at expounding the chemopotentiating effects and underlying mechanisms of betulinic acid, a primary therapeutic triterpene of C. orbiculatus in combination with gemcitabine chemotherapy. The preparation of betulinic acid was optimized using ultrasonic-assisted extraction method. Gemcitabine-resistant cell model was established by induction of the cytidine deaminase. MTT, colony formation, EdU incorporation and Annexin V/PI staining assays were used to evaluate cytotoxicity, cell proliferation and apoptosis in BxPC-3 pancreatic cancer cell line and H1299 non-small cell lung carcinoma cell line. Comet assay, metaphase chromosome spread and γH2AX immunostaining were applied for DNA damage assessment. Western blot and co-immunoprecipitation was used to detect the phosphorylation and ubiquitination of Chk1. Mode of action of gemcitabine in combination with betulinic acid was further captured in BxPC-3-derived mouse xenograft model. We noticed that the extraction method had an impact on the thermal stability of C. orbiculatus. Ultrasound-assisted extraction at room temperature in shorter processing time could maximize the overall yields and biological activities of C. orbiculatus. The major constituent was identified as betulinic acid, and the pentacyclic triterpene represented the prominent anticancer activity of C. orbiculatus. Forced expression of cytidine deaminase conferred acquired resistance to gemcitabine, while betulinic acid displayed equivalent cytotoxicity toward gemcitabine-resistant and sensitive cells. A combination therapy of gemcitabine with betulinic acid produced synergistic pharmacologic interaction on cell viability, apoptosis and DNA double-strand breaks. Moreover, betulinic acid abrogated gemcitabine-triggered Chk1 activation by destabilizing Chk1 loading via proteasomal degradation. The combination of gemcitabine and betulinic acid significantly retarded BxPC-3 tumor growth in vivo compared to single-agent gemcitabine treatment alone, accompanied with reduced Chk1 expression. These data provide evidence that betulinic acid is a potential candidate for chemosensitization as a naturally occurring Chk1 inhibitor and warrants further preclinical evaluation.

Pancreatic Stromal Cell-derived Oncostatin M Confers Drug Resistance to a Multi-tyrosine Kinase Inhibitor in Pancreatic Cancer Cells.

Pancreatic cancer is known to have one of the worst prognoses of all cancers, and its tumor cells are highly resistant to chemotherapeutic drugs. Pancreatic cancer cells coexist with stromal cells; however, their involvement in anticancer drug resistance remains poorly understood. Thus, in this study, we analyzed drug sensitivity using an in vitro co-culture system containing pancreatic cancer cells and stromal cells treated with a compound library. We examined the viability of the pancreatic cancer cell lines BxPC-3, Capan-1, and Panc-1 against compounds in an in vitro co-culture model containing pancreatic stromal cells (PSCs) and analyzed the protein expression for drug resistance by western blotting. We found that co-cultured pancreatic cancer cells were resistant to vandetanib, which is an inhibitor of multi-tyrosine kinases. The key factor involved in drug resistance in these pancreatic cancer cells was oncostatin M, which was secreted by stromal cells. The addition of oncostatin M increased the vandetanib resistance of pancreatic cancer cells, while it inhibited the suppression of insulin receptor substrate-1 (IRS1) and the phosphorylation of extracellular signal-regulated kinase (ERK) by vandetanib. Oncostatin M secreted by stromal cells derived from the pancreas activates the IRS1-ERK axis, causing resistance to vandetanib.

Systemic Analyses of Cuproptosis-Related lncRNAs in Pancreatic Adenocarcinoma, with a Focus on the Molecular Mechanism of LINC00853.

Pancreatic cancer (PC) is a deadly malignant digestive tumor with poor prognoses and a lack of effective treatment options. Cuproptosis, a recently identified copper-dependent programmed cell death type, has been implicated in multiple cancers. Long non-coding RNAs (lncRNAs) are also linked to the progression of PC. However, the role and prognostic values of cuproptosis-related lncRNAs in pancreatic adenocarcinoma (PAAD) remain unclear. In this study, we systemically analyzed the differential expressions and prognostic values of 672 cuproptosis-related lncRNAs in PAAD. Based on this, a prognostic signature including four lncRNAs (LINC00853, AC099850.3, AC010719.1, and AC006504.7) was constructed and was able to divide PAAD patients into high- and low-risk groups with significantly different prognoses. Next, we focused on lncRNA LINC00853. The differential expressions of LINC00853 between normal tissue and PAAD samples were validated by qRT-PCR. LINC00853 was knocked down by siRNA in PC cell lines BxPC-3 and PANC-1 and the oncogenic role of LINC00853 was validated by CCK8, colony formation, and EdU assays. Subsequently, LINC00853 knockdown cells were subjected to tumor xenograft tests and exhibited decreased tumor growth in nude mice. Mechanistically, knockdown of LINC00853 significantly reduced cellular glycolysis and enhanced cellular mitochondrial respiration levels in PC cells. Moreover, knockdown of LINC00853 decreased the protein level of a glycolytic kinase PFKFB3. Finally, glycolysis tests and functional tests using LINC00853 and HA-PFKFB3 indicated that the effects of LINC00853 on glycolysis and cell proliferation were mediated by PFKFB3. In conclusion, our systemic analyses have highlighted the important roles of cuproptosis-related lncRNAs in PAAD while the prognostic signature based on them showed excellent performance in PAAD patients and is expected to provide clinical guidance for individualized treatment. In addition, our findings provide a novel mechanism by which the LINC00853-PFKFB3 axis critically regulates aerobic glycolysis and cell proliferation in PC cells.

Abstract 2642: BL-B01D1, a novel EGFR×HER3-targeting ADC, demonstrates robust anti-tumor efficacy in preclinical evaluation

Abstract EGFR and HER3, members of the human epidermal growth factor receptor (ErbB) family, are targeted in cancer therapy due to their over-expression and pathway dependence in common human epithelial carcinoma tumors. To develop a promising therapeutic anti-tumor agent, we generated BL-B01D1, an EGFR×HER3-targeting ADC, which can bind to EGFR and/or HER3 positive cells and is expected to be superior to anti-EGFR and anti-HER3 ADCs. It is comprised of a bispecific antibody against EGFR/HER3 (SI-B001), a cathepsin B cleavable linker, and a novel topoisomerase I inhibitor agent (Ed-04), which is a derivative of the alkaloid camptothecin, driving cell cycle arrest at the S phase and subsequent apoptosis. BL-B01D1 achieves a high drug-to-antibody-ratio (DAR=8) with a highly stable linker. The pharmacological potential of this ADC was evaluated in comparison to its parental single antigen-targeting ADCs in xenograft models composed of either the human colorectal cancer cell line SW620 or pancreatic cancer cell line BxPC3. The tumor inhibition activity of BL-B01D1 was compared with ADCs prepared from each parental anti-EGFR or anti-HER3 mAb conjugated with the same linker and payload. The bispecific ADC, BL-B01D1 exhibited stronger tumor inhibition capacity than the anti-EGFR ADC and the anti-HER3 ADC separately. The preclinical studies suggest BL-B01D1, as an EGFR×HER3-targeting ADC, might be a promising novel agent with activity toward a broad range of human cancers. The clinical phase I has been progressing and the available data exhibit excellent efficacy but low levels of targeted toxicity in the non-small cell lung cancer (NSCLC) treatment setting. Overall, these data suggest BL-B01D1 has potential to serve as a novel, efficacious therapeutic agent for NSCLC with similar therapeutic impact as DS-8201 has in breast cancer treatment. Citation Format: Weili Wan, Shuwen Zhao, Shi Zhuo, Yong Zhang, Lan Chen, Gangrui Li, Blair Renshaw, Jahan Salar Khalili, Sa Xiao, Yi Zhu. BL-B01D1, a novel EGFR×HER3-targeting ADC, demonstrates robust anti-tumor efficacy in preclinical evaluation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2642.

Treatment of Human Pancreatic Cancers Following Local and Systemic Administration of Oncolytic Adenovirus Serotype 35.

Oncolytic adenoviruses (Ads) (OAds) are gaining attention as an effective remedy for pancreatic cancer. Most OAds are based on human Ad serotype 5 (Ad5) (OAd5); however, two major drawbacks of OAd5 have been reported. Expression of coxsackievirus-adenovirus receptor, a primary infection receptor of Ad5, is often decreased on malignant tumor cells, including pancreatic cancers. More than 60% of adults have neutralizing antibodies against Ad5. Previously, we developed an OAd composed of Ad serotype 35 (Ad35) (OAd35). Ad35 recognizes CD46, which is often up-regulated on pancreatic cancers. In addition, only 20% or fewer adults have anti-Ad35 neutralizing antibodies. We examined the tumor cell lysis activities of OAd35 in the four human pancreatic cancer cell lines in the presence and absence of human serum. The tumor growth suppression effects of OAd35 after local and systemic administration were evaluated in nude mice bearing human pancreatic tumors. OAd35 showed higher levels of tumor cell lysis activities than OAd5 in the human pancreatic cancer cell lines AsPC-1 and BxPC-3. Although the in vitro tumor cell lysis activities of OAd5 against MIA PaCa-2 and PANC-1 cells were strongly attenuated in the presence of human serum, OAd35 mediated comparable levels of tumor cell lysis in the presence and absence of human serum. Systemic administration of OAd5 did not mediate significant growth inhibition against the subcutaneous BxPC-3 tumor. On the other hand, OAd35 significantly suppressed tumor growth. OAd35 would be suitable as an alternative anticancer agent for pancreatic cancer.

Modulatory Effects of Metformin on Farnesoid X receptor and Specificity Protein 1 in Human Pancreatic Cancer BxPC-3 Cells

Background: Pancreatic cancer is the fourth major cause of death, accounting for 7% of cancer-related deaths. Metformin (antihyperglycemic agent) users had a 62% lower risk of developing pancreatic cancer when compared to metformin non-users. Objective: This research aims to study the role of the Farnesoid X receptor (FXR) receptor in human pancreatic cancer cell line BxPC-3 and metformin’s modulatory effects on this receptor. Material and methods: Cell viability was assessed using MTT assay for INT747 (FXR agonist) and metformin, FXR and Specificity Protein 1 (Sp1) mRNA and protein levels were measured by quantitative reverse transcription-polymerase chain reaction (RT-qPCR) and western blot, respectively. Results: INT747 increased the growth and viability of BxPc-3 cells in addition to a significant increase in FXR and SP1 mRNA and protein levels. In contrast, BxPC-3 cells viability was significantly reduced by metformin in a dose- and time-dependent manner with downregulation of FXR and SP1 at mRNA and protein levels Conclusion: FXR may act as an oncogenic factor in pancreatic cancer BxPC-3 cells by increasing FXR and SP1 expression, while metformin significantly reduced FXR mRNA and protein levels in BxPC-3 cells, which may be due to a reduction in SP1 expression.

Upstream stimulatory factor 2 inhibits erastin-induced ferroptosis in pancreatic cancer through transcriptional regulation of pyruvate kinase M2

Ferroptosis is considered as a potential target in cancer treatment including chemotherapy and radiotherapy, however, its regulatory mechanism on pancreatic cancer (PC) is not fully understood. Herein, we explored the role of upstream stimulatory factor 2 (USF2) and pyruvate kinase M2 (PKM2) in ferroptosis in PC cells. USF2 and PKM2 were highly expressed in PC tissues and USF2 was positively correlated with PKM2. PC cell lines BxpC-3 and AsPC-1 were transfected with small interfering RNAs against USF2/PKM2 or USF2 overexpressing plasmids or co-transfected with small interfering RNAs against PKM2 and USF2 overexpressing plasmids. Twenty-four hours after cell transfection, ferroptotic cell death was induced by incubation with 20 μmol/l erastin for 24 h. Ferroptotic cell death was promoted by USF2 knockdown and inhibited by USF2 overexpression. USF2 knockdown increased lipid reactive oxygen species and malonaldehyde generation and decreased glutathione concentration and glutathione peroxidase 4 expressions, indicating the enhanced lipid peroxidation. USF2 knockdown also increased ferrous iron levels and ferritin heavy chain expressions and reduced solute carrier family 7 member 11 expressions. However, USF2 overexpression reversed these changes. Furthermore, dual-luciferase reporter assay, chromatin immunoprecipitation assay and DNA pull down assay validated that USF2 transcriptionally regulated PKM2 expression through binding to its promoter. Interestingly, PKM2 also negatively regulated ferroptosis and PKM2 knockdown markedly impaired the effects of USF2 on lipid peroxidation and ferroptotic cell death. This study demonstrated that USF2 negatively regulated ferroptosis in PC cells through transcriptional regulation of PKM2, providing new evidences for uncovering the regulatory mechanism of ferroptosis on PC.

Pomegranate juice anthocyanidins induce cell death in human cancer cells by mobilizing intracellular copper ions and producing reactive oxygen species.

Anthocyanidins are the most abundant polyphenols in pomegranate juice. This class of molecules includes Delphinidin (Del), Cyanidin (Cya), and Pelargonidin (Pel). Using prostate, breast and pancreatic cancer cell lines PC3, MDA-MB-231, BxPC-3 and MiaPaCa-2, we show that anthocyanidins inhibit cell proliferation (measured by MTT assay) and induce apoptosis like cell death (measured by DNA/Histone ELISA). Copper chelator neocuproine and reactive oxygen species scavengers (thiourea for hydroxyl radical and superoxide dismutase for superoxide anion) significantly inhibit this reaction thus demonstrating that intracellular copper reacts with anthocyanidins in cancer cells to cause DNA damage via ROS generation. We further show that copper-supplemented media sensitizes normal breast epithelial cells (MCF-10A) to Del-mediated growth inhibition as determined by decreased cell proliferation. Copper supplementation results in increased expression of copper transporters Ctr1 and ATP7A in MCF-10A cells, which is attenuated by the addition of Del in the medium. We propose that the copper mediated, ROS-induced mechanism of selective cell death of cancer cells may in part explain the anticancer effects of anthocyanidins.

Proof of Principle of Combining Fluorescence-Guided Surgery with Photoimmunotherapy to Improve the Outcome of Pancreatic Cancer Therapy in an Orthotopic Mouse Model

BackgroundPancreatic cancer is a recalcitrant disease in which R0 resection is often not achieved owing to difficulty in visualization of the tumor margins and proximity of adjacent vessels. To improve outcomes, we have developed fluorescence-guided surgery (FGS) and photoimmunotherapy (PIT) using a fluorescent tumor-specific antibody.MethodsNude mice received surgical orthotopic implantation (SOI) of the human pancreatic cancer cell line BxPC-3 expressing green fluorescent protein. An anti-carcinoembryonic antigen-related cell adhesion molecule (CEACAM) monoclonal antibody (6G5j) was conjugated to the 700-nm fluorescent dye IR700DyeDX (6G5j-IR700DX). Three weeks after SOI, 16 mice received 50 μg 6G5j-IR700DX via the tail vein 24 h before surgery and were randomized to two groups: FGS-only (n = 8) and FGS + PIT (n = 8). All tumors were imaged with the Pearl Trilogy imaging system and resected under the guidance of the FLARE imaging system. The FGS + PIT group received PIT of the post-surgical bed at an intensity of 150 mW/cm2 for 30 min. Mice were sacrificed 4 weeks after initial surgery, and tumors were imaged with a Dino-Lite digital microscope, excised, and weighed.ResultsThe 6G5j-IR700DX dye illuminated the orthotopic pancreatic tumors for FGS and PIT. The metastatic recurrence rate was 100.0% for FGS-only and 25.0% for FGS + PIT (p = 0.007). The average total recurrent tumor weight was 2370.3 ± 1907.8 mg for FGS-only and 705.5 ± 1200.0 mg for FGS + PIT (p = 0.039).ConclusionsFGS and adjuvant PIT can be combined by using a single antibody–fluorophore conjugate to significantly reduce the frequency of pancreatic cancer recurrence.