Potential Of Pancreatic Cancer Cells Research Articles

TLK1 Inhibition Enhances the Anticancer Effect of Deep UV Irradiation Through CHK1 Activation.

A deep ultraviolet (DUV) light-emitting diode (LED) is a device that can irradiate electromagnetic waves from 250 nm to 350 nm. Tousled-like kinase 1 (TLK1) encodes a nuclear serine/threonine kinase, which is thought to influence the effects of DUV irradiation in cancer. The aim of this study was to clarify the interaction of TLK1 with DUV irradiation-induced DNA damage in cancer cells. Pancreatic cancer cell lines were treated with or without DUV. TLK1 expression and phosphorylation in the two groups were examined. Then, these cancer cell lines were treated with thioridazine (THD), DUV or both. Thereafter, cytomorphology and apoptosis were assessed. Several proteins related to DNA damage, were analyzed in cancer cells treated with DUV and THD. Tumors in a subcutaneous xenograft model were treated with THD, DUV, or both for six weeks. DUV irradiation induced the phosphorylation of TLK1 in pancreatic cancer cell lines. Cytomorphology was significantly changed in pancreatic cancer cells treated with DUV and THD. TLK1 inhibition enhanced DUV irradiation-induced apoptosis in cancer cells. Interestingly, CHK1 and pCHK1 expression was suppressed after TLK1 inhibition. In addition, inhibition of MRE11 led to a decrease in the expression of CHK1 and pCHK1, accompanied by a notable increase in apoptosis. In the subcutaneous xenograft models, the tumor volume in the DUV and THD groups was lower than that in the other groups. TLK1 phosphorylation is an important event in DUV irradiation. DUV irradiation combined with TLK1 inhibition has therapeutic potential in pancreatic cancer cells.

Abstract A069: Study of MUC16/ERBB axis in pancreatic cancer

Abstract Background: Pancreatic cancer is the third leading cause of cancer-related deaths due to its poor prognosis and highly malignant nature. The altered expression of glycans and glycoproteins is associated with malignancy. MUC16 (also known as CA125) is a member of mucin family of glycoproteins known to line epithelial cells for protection and lubrication and is overexpressed in several cancer types, including pancreatic cancer, often linked with enhanced disease progression, metastasis, and reduced patient survival. Significance: Circulating levels of MUC16/CA125 has been used as a biomarker to monitor adenocarcinoma for decades. However, the functional role of CA125/MUC16 is yet to be elucidated due to a lack of studies on its large, heavily glycosylated structure and unknown functional domains. We present evidence that in addition to serving as a biomarker, circulating MUC16 has pro-tumorigenic activities. Hypothesis: Based on recent findings, we hypothesize that isoforms of MUC16 have high avidity for ErbB receptor and integrin complexes, with concomitant activation of downstream signaling cascades that include Akt and FAK, respectively. These result in the increased tumorigenic potential of pancreatic cancer cells in an autocrine manner. Experimental Design: There are four members of ErbB receptors; where receptor dimerization is a function of ligand binding and results in distinct downstream oncogenic signaling cascades. We evaluated the binding of MUC16 to different ErbB receptors, and its capacity to activate downstream signaling pathways using pancreatic cell line models that have different combinations of knock out/down of each ErbB receptor. We evaluated the global changes in the phosphorylation of oncogenic signaling molecules due to MUC16 binding using Reverse Phase Protein Array (RPPA). Results: We found that MUC16 activates Erbb4 (Y1162) along with other members of ErbB receptor family, where glycosylation of MUC16 is crucial for its biological activity. MUC16 enhanced oncogenic signaling through the phosphorylation of various downstream molecules and activated PI3K, RTK, MAPK, and DNA repair pathways. Our future directions include elucidating the molecular mechanism by which MUC16 activates the oncogenic signaling cascades via binding to ErbB receptors using our pancreatic cell line-based models. Conclusions: Understanding the biological activity of MUC16 and its cleaved product will further help in investigating the role of MUC16 in tumor microenvironment and at distant organ sites to influence the metastatic niche. Citation Format: Amina Baniya, Michael A. (Tony) Hollingsworth. Study of MUC16/ERBB axis in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr A069.

RRM1 is mediated by histone acetylation through gemcitabine resistance and contributes to invasiveness and ECM remodeling in pancreatic cancer.

The invasiveness of pancreatic cancer and its resistance to anticancer drugs define its malignant potential, and are considered to affect the peritumoral microenvironment. Cancer cells with resistance to gemcitabine exposed to external signals induced by anticancer drugs may enhance their malignant transformation. Ribonucleotide reductase large subunit M1 (RRM1), an enzyme in the DNA synthesis pathway, is upregulated during gemcitabine resistance, and its expression is associated with worse prognosis for pancreatic cancer. However, the biological function of RRM1 is unclear. In the present study, it was demonstrated that histone acetylation is involved in the regulatory mechanism related to the acquisition of gemcitabine resistance and subsequent RRM1 upregulation. The current invitro study indicated that RRM1 expression is critical for the migratory and invasive potential of pancreatic cancer cells. Furthermore, a comprehensive RNA sequencing analysis showed that activated RRM1 induced marked changes in the expression levels of extracellular matrix‑related genes, including N‑cadherin, tenascin‑C and COL11A. RRM1 activation also promoted extracellular matrix remodeling and mesenchymal features, which enhanced the migratory invasiveness and malignant potential of pancreatic cancer cells. The present results demonstrated that RRM1 has a critical role in the biological gene program that regulates the extracellular matrix, which promotes the aggressive malignant phenotype of pancreatic cancer.

The effect of silicon phthalocyanine on cell death and mitochondrial membrane potential in pancreatic cancer cells

Silicon (SiPcs) phthalocyanines are advantageous because they do not aggregate due to their special structural features. Therefore, they have been widely used in a range of areas in chemical and biological technology. One of the common applications is the use of phthalocyanines on cancer therapies. Pancreas cancer is one of the most common cancers with a high rate of mortality around the world. In this study we therefore aimed to investigate the potential of SiPcs molecules which we previously synthesized for the first time, on increased cell death and the effect on mitochondrial activity in pancreatic cancer cells. The results showed the significantly selective cytotoxic effect of SiPc on cancer cells compared to normal cells. Mitochondrial membrane potential was not different in cancer cells but in normal cells after SiPcs treatment. Pre-incubation time (24h) of SiPcs before light irradiation induced more significant cytotoxicity in pancreatic cancer cells but not in normal cells compared to prolonged pre-incubation (48). This study revisited the biological function of previously synthesized SiPcs, and the results conclude the cytotoxic activity of SiPcs on pancreas cancer. These preliminary findings can be extended for other cancer types and detailed with in vivo models in the future.

Nerve Growth Factor (NGF) Encourages the Neuroinvasive Potential of Pancreatic Cancer Cells by Activating the Warburg Effect and Promoting Tumor Derived Exosomal miRNA-21 Expression.

Background It has been reported that signaling from the nerve growth factor (NGF) pathway associated with peripheral nerves is able to contribute to perineural invasion (PNI) of pancreatic cancer (PC). Nevertheless, the underlying mechanism by which NGF leads to PNI remained poorly understood. Methods Western blotting was employed to determine NGF level in PC and paracarcinoma tissues and in PC cell lines as well as pancreatic ductal epithelial cells. MiaPaCa-2 and CFPAC-1 cells were treated with 100 ng/ml of NGF or the NGF inhibitor Tanezumab for 24 h, CCK-8 and Transwell assays were employed to test cell proliferation, invasion, and migration, respectively. TrkA expression was knocked down in MiaPaCa-2 and dorsal root ganglion (DRG) cells treated with NGF to determine its effect on the Warburg effect. To reveal that the NGF-TrkA signaling pathway was closely associated with PC PNI, in vitro neuroinvasion model was established by using MiaPaCa-2 cells via coculturing DRG cells in Matrigel. Further, exosomes were extracted from PC cells and identified by examining the levels of specific markers for exosomes. Then RT-qPCR was applied to test miR-21-5p level in tumor derived exosomal (TDE-miR-21-5p). RIP assay was performed to validate NGF and miR-21 binding ability in MiaPaCa-2 cells. Rescue experiments were performed by using coprocessing of Tanezumab and miR-21-5p mimic on MiaPaCa-2 cells, followed by coculture with DRG cells. Subsequently, we used a model of neuroinvasion in nude mice to assess the effect of NGF in vivo on tumor nerve invasion as well as on nociceptive transmission. Results NGF level was preeminently higher in PC tissues and cell lines than in paracarcinoma tissues and normal pancreatic epithelial cell lines. NGF promoted MiaPaCa-2 and CFPAC-1 cell invasion and migration, while Tanezumab treatment showed the opposite results. Besides, NGF binding to TrkA receptors encouraged the intracellular Warburg effect in PC and DRG cells. TrkA blocking-up could restrain NGF induced PC cell migration and neural invasion. Mechanistically, NGF could upregulate TDE-miR-21-5p levels, and DRG cells took up TDE to activate the Warburg effect and stimulate nociceptor gene expression. miR-21-5p inhibitor could abolish the facilitative effect of NGF on PNI in MiaPaCa-2 cells. In vivo tumorigenesis experiments, Tanezumab markedly alleviated nerve invasion of PC cells as well as relieved nociceptive conduction in animal models. Conclusions These findings displayed that NGF/TrkA encouraged the neuroinvasive potential of PC cells by activating the Warburg effect in DRG cells through upregulation of TDE-miR-21-5p expression.

Factors released by low and high-LET irradiated fibroblasts modulate migration and invasiveness of pancreatic cancer cells.

IntroductionRadiotherapy represents a major treatment option for patients with pancreatic cancer, however, its benefits remain limited also due to the ability of cancer cells to migrate to the surrounding tissues. Low-LET ionizing radiation is well known to promote tumor cell migration and invasion, nevertheless, little data provided by studies using high-LET radiation has led to ambiguous findings. What is hypothesized to be fundamental in the modulation of migration of tumor cells exposed to ionizing radiation is the influence of the microenvironment. Therefore, the properties of cells that populate the tumor stroma cannot be ignored when studying the influence of radiation on the migratory and invasive capacity of cancer cells. This is especially important in the case of pancreatic malignancies that are characterized by an abundance of stromal cells, including cancer-associated fibroblasts, which are known to orchestrate the cross-talk with tumor cells.AimThe current study aims to investigate whether the presence of factors released by irradiated fibroblasts affects the migratory and invasive capacity of pancreatic cancer cells exposed to different doses of photons or C-ions.Materials and methodsAsPC-1 and AG01522 cells were irradiated with the same dose of photons or C-ions at room temperature. Through Boyden chamber assay, we tested whether factors secreted by irradiated fibroblasts may influence tumor cell migration, while the invasiveness of AsPC-1 cells was assessed using matrigel precoated inserts in which medium collected from non-irradiated (0 Gy), photon and C-ion irradiated fibroblasts, was added. Data were analyzed by Student t-test using GraphPad software. The mean ± s.d. was determined with a significance level of p<0.05.ResultsIn the presence of conditioned medium collected from 1 Gy and 2 Gy photon irradiated fibroblasts, the number of migrated tumor cells increased (P<0.0360, P<0.0001) but decreased at 4 Gy dose (P<0.002). There was a trend of reduction in migration (P<0.0460, P<0.038, P<0.0024, P<0.0002), as well as a decrease in invasiveness (P<0.0525, P<0.0035, P<0.0868, P<0.0310) after exposure to 0.5 Gy, 1 Gy, 2 Gy and 4 Gy of C-ions.ConclusionsThe presence of irradiated fibroblasts affected the invasiveness capability of pancreatic cancer cells, probably by the reciprocal release of soluble factors whose production is differently modulated after high or low-LET radiation. Understanding the effects of irradiation on the metastatic potential of pancreatic cancer cells is of utmost importance for improving the outcome and tailoring the therapeutic approach. This challenging scenario requires a continuous and multidisciplinary approach that involves clinicians together with researcher experts in oncological and radiation treatment. In the last years, including preclinical experiences in a multidisciplinary approach has proved to be a winning strategy in clinical oncological research.

Abstract 3950: Targeting ribosome biogenesis is a novel strategy to suppress the growth of pancreatic cancer

Abstract Pancreatic cancer is the fourth leading cause of cancer-related deaths in the United States with limited therapeutic approaches. Dysregulation of the ribosome biogenesis process was observed in various cancer including pancreatic cancer. Therefore, strategically targeting ribosome biogenesis could be a novel approach for pancreatic cancer treatment. One such approach is to target ribosome biogenesis is via small molecule inhibitors of RNA Polymerase I as these inhibitors have shown promising anti-cancer activity in pre-clinical and clinical studies. We observed differential constitutive expression of various ribosomal proteins including RPA-194 in human PanCa cells when compared with normal HPDE cells. Therefore, we hypothesized that targeting RNA pol I will inhibit the growth of pancreatic cancer. In this study, we for the first time evaluated the therapeutic effect of a novel RNA polymerase I inhibitor (BMH-21) against PanCa in pre-clinical model systems. BMH-21 significantly inhibited the ribosome biogenesis process in various pancreatic cancer cells (Panc-1, AsPC1, BxPC3, MiaPaCa-2) as determined by inhibition of rRNA synthesis and POL I occupancy on rDNA. BMH-21 treatment of pancreatic cancer cells significantly degraded RPA194 protein as determined by Western blot and confocal microscopy analysis. BMH-21 treatment (0.25-5µM) showed differential IC50 in various pancreatic cancer cells which were correlated with the expression of its target proteins RPA194 and RPA135 expression. In our flow cytometry experiment, we observed a significant G0/G1 cell cycle arrest and increase Annexin V and Annexin V7-AAD positive cells in BMH-21 treated pancreatic cancer cells as compared to the vehicle treatment group suggesting its apoptosis-inducing potential in pancreatic cancer cells. BMH-21 treatment inhibited growth and metastatic phenotypes of various PanCa cells as analyzed by various functional assays (colony formation and atomic force microscopy analyses). We also evaluated the effect of BMH-21 on various kinases, which regulate ribosome biogenesis. Interestingly, we observed BMH-21 significantly (P&amp;lt;0.01) downregulated the phosphorylation of AKT (Ser473) and WNK-1 (Thr60) kinases and Stat3 phosphorylation at Ser727 and upregulates pChk2 kinase in PanCa cells. BMH-21 (2 mg/kg i.p) significantly (P&amp;lt;0.01) inhibited the growth of pancreatic tumor in an orthotopic xenograft mouse model. Excised tumor tissues of BMH-21 treated mice showed decreased expression of various ribosomal proteins including RPA194 and RPA195 along with various cell proliferative markers (ki67 and PCNA) as compared to vehicle-treated group. Taken together, our results demonstrated that targeting the ribosome biogenesis process is a novel therapeutic strategy for the management of pancreatic cancer and BMH-21 could be used as a potential therapeutic agent for the treatment of advanced pancreatic cancer. Citation Format: Carlos Perez, Mudassier Ahmad, Andrew Massey, Asif Shahriar, Emmanuel Anning, Vivek Kashyap, Neeraj Chauhan, Anupam Dhasmana, Manish Tripathi, Subhash Chauhan, Bilal Hafeez. Targeting ribosome biogenesis is a novel strategy to suppress the growth of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3950.

TGF-β1-induced RAP2 regulates invasion in pancreatic cancer.

Pancreatic cancer is highly lethal due to its aggressive invasive properties and capacity for metastatic dissemination. Additional therapeutic targets and effective treatment options for patients with tumours of high invasive capacity are required. Ras-related protein-2a (RAP2) is a member of the GTP-binding proteins. RAP2 has been reported to be widely upregulated in many types of cancers via regulating cytoskeleton reorganization, cell proliferation, migration, and adhesion, as well as inflammation. As a member of the RAS oncogene family, which has been demonstrated to drive pancreatic cancer oncogenesis and many other malignancies, the physiological roles of RAP2 in pancreatic cancer have seldom been discussed. In the present study, we explored the correlation between RAP2 expression and the prediction of overall survival of pancreatic cancer patients. Mechanistic studies were carried out to shed light on the role of RAP2 in pancreatic cancer invasion and how RAP2 is regulated in the invasive process. Our results demonstrated that patients with higher RAP2 expression showed unfavourable prognoses. studies demonstrated that silencing of inhibited the invasion of pancreatic cancer cells. Moreover, our results demonstrated that transforming growth factor-β1 (TGF-β1), an inducer of the metastatic potential of pancreatic cancer cells, regulates the expression of RAP2 via the transcription factor c-Myc. In conclusion, the present study uncovered RAP2 as a novel predictive marker and therapeutic target for pancreatic cancer.

The Effects of Analgesics on the Migration of Pancreatic Cancer Cells.

Adenocarcinoma of the pancreas is one of the most aggressive malignant diseases in humans. Characteristics of this tumour type are poor response to radiotherapy and chemotherapeutic agents as well as metastasis in the absence of an organ capsule. The best therapeutic option is surgical removal of the tumour followed by chemotherapy or radiotherapy. Yet, even after surgical R0-resection, the 5-year survival probability is only about 20% because of the high recurrence rate of this tumour and complications due to metastases. Furthermore, recent studies have shown that the perioperative period is a particularly vulnerable phase, during which tumour progression and metastasis may be facilitated. The effects of analgesics administered during the perioperative period are still unknown. The present work investigated the effects of analgesics on pancreatic cancer cell migration in vitro. The migratory potential of pancreatic cancer cells was analysed using a Cell Migration Assay Kit with a Boyden chamber, in which cells migrate through a semi-permeable membrane under different stimuli. Cell concentration was measured by reading fluorescence (Ex/Em=530/590 nm) in a plate reader. Migration in PANC-1 pancreatic cancer cells was significantly decreased after 24 h stimulation with 100 μM of ropivacaine, 100 nM of sufentanil, 1,000 μM of ropivacaine and 1,000 nM of sufentanil. In the PaTu 8988t cell line, incubation with 10 μM of ropivacaine caused a slight but statistically significant increase in migration, whereas lidocaine, metamizole and paracetamol did not significantly affect migration. The risk of tumour progression and metastasis seems to be increased during major oncological surgical interventions. The recent advances in the molecular and biological understanding of pathogenesis of pancreatic cancer have not yet significantly improved patient outcome. Therefore, further studies are needed to identify the underlying mechanisms of this aggressive tumour and establish new therapeutic options for the future.

Serum of Mice Immunized with MT1-MMP Metalloproteinase Reduces Migration Potential of Pancreatic Cancer Cells

Serum of Mice Immunized with MT1-MMP Metalloproteinase Reduces Migration Potential of Pancreatic Cancer Cells

Abstract 1986: p53/FBXL20 axis negatively regulates the protein stability of PR55α, a PP2A regulatory subunit

Abstract PP2A holoenzymes are the majority of Ser/Thr phosphatases in human cells and each PP2A complex contains one scaffold subunit, one catalytic subunit, and one regulatory subunit. PP2A regulatory subunits, existing in four sub-families encoded by 15 genes, determine the substrate specificities and intracellular localizations of PP2A. We previously reported an essential role for PR55α, a PP2A regulatory subunit, in the support of malignant potential of pancreatic cancer cells, which includes promoting YAP-activation that supports anchorage-independent growth and metastasis. Furthermore, our data showed that PR55α level is elevated in pancreatic cancer relative to normal tissues and high PR55α levels correlate with poor patient survival. The studies in this report reveal a novel mechanism by which the p53 tumor suppressor negatively regulates PR55α protein stability. The results show that p53 inactivation by siRNA-knockdown, gene-deletion, HPV-E6 promoted degradation, or p53R175H mutant expression all results in the increase of PR55α expression. Subsequent studies demonstrate that this p53 function is mediated through its target gene FBXL20, a substrate recognition component of the SCF (Skp_Cullin_F-box) ubiquitin ligase complex that facilitates proteasomal degradation. As a result, the expression of mutant p53R175H in human pancreatic ductal cells mimics the PR55α effect, increasing c-Myc protein stability, and promoting anchorage-independent proliferation. Additionally, FBXL20 mRNA levels are significantly reduced in pancreatic cancers relative to normal control, and low FBXL20 levels correlate with poor patient survival, both of which inversely resemble the pathological effects of PR55α in pancreatic cancer. Collectively, these results define a novel p53 function in the suppression of PR55α expression. Citation Format: Ying Yan, Lepakshe Madduri, Nichole Brandquist, Chitra Palanivel, Sumin Zhou, Charles Enke, Michel Ouellette. p53/FBXL20 axis negatively regulates the protein stability of PR55α, a PP2A regulatory subunit [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1986.

Retracted] Polyphenol‑rich extract of Salivachinensis exhibits anticancer activity in different cancer cell lines, and induces cell cycle arrest at the G0/G1‑phase, apoptosis and loss of mitochondrial membrane potential in pancreatic cancer cells.

Following the publication of the above paper, a concerned reader drew to the Editor's attention that several figures (Figs.3, 4 and 6) contained apparent anomalies, including repeated patternings of data within the same figure panels. Furthermore, Fig.6 contained data that bore striking similarities to data published in Fig.8 in another paper published in Molecular Medicine Reports, which has now been retracted [Zhu Y‑Y, Huang H‑Y and WuY‑L: Anticancer and apoptotic activities of oleanolic acid are mediated through cell cycle arrest and disruption of mitochondrial membrane potential in HepG2human hepatocellular carcinoma cells. Mol Med Rep12: 5012‑5018, 2015]. After having conducted an independent investigation in the Editorial Office, the Editor of Molecular Medicine Reports has determined that the above paper should be retracted from the Journal on account of a lack of confidence concerning the originality and the authenticity of the data. The authors were asked for an explanation to account for these concerns, but the Editorial Office never received any reply. The Editor regrets any inconvenience that has been caused to the readership of the Journal. [the original articles was published in Molecular Medicine Reports 12: 4843‑4850, 2015; DOI: 10.3892/mmr.2015.4074].

NR5A2 transcriptional activation by BRD4 promotes pancreatic cancer progression by upregulating GDF15

NR5A2 is a transcription factor regulating the expression of various oncogenes. However, the role of NR5A2 and the specific regulatory mechanism of NR5A2 in pancreatic ductal adenocarcinoma (PDAC) are not thoroughly studied. In our study, Western blotting, real-time PCR, and immunohistochemistry were conducted to assess the expression levels of different molecules. Wound-healing, MTS, colony formation, and transwell assays were employed to evaluate the malignant potential of pancreatic cancer cells. We demonstrated that NR5A2 acted as a negative prognostic biomarker in PDAC. NR5A2 silencing inhibited the proliferation and migration abilities of pancreatic cancer cells in vitro and in vivo. While NR5A2 overexpression markedly promoted both events in vitro. We further identified that NR5A2 was transcriptionally upregulated by BRD4 in pancreatic cancer cells and this was confirmed by Chromatin immunoprecipitation (ChIP) and ChIP-qPCR. Besides, transcriptome RNA sequencing (RNA-Seq) was performed to explore the cancer-promoting effects of NR5A2, we found that GDF15 is a component of multiple down-regulated tumor-promoting gene sets after NR5A2 was silenced. Next, we showed that NR5A2 enhanced the malignancy of pancreatic cancer cells by inducing the transcription of GDF15. Collectively, our findings suggest that NR5A2 expression is induced by BRD4. In turn, NR5A2 activates the transcription of GDF15, promoting pancreatic cancer progression. Therefore, NR5A2 and GDF15 could be promising therapeutic targets in pancreatic cancer.

CCL26 is upregulated by nab-paclitaxel in pancreatic cancer&amp;ndash;associated fibroblasts and promotes PDAC invasiveness through activation of the PI3K/AKT/mTOR pathway

Recently, the combined use of FOLFIRINOX (leucovorin and fluorouracil plus irinotecan and oxaliplatin) and gemcitabine plus nab-paclitaxel has significantly improved the prognosis of patients with pancreatic cancer. However, there is still a high proportion of patients who develop metastatic pancreatic cancer in the course of chemotherapy or within a short period after chemotherapy. Previous reports have shown that chemotherapy-driven cytokine storms or the direct effects of certain chemotherapeutics on stromal and/or immune cells collectively change the microenvironment of the primary tumor, thus indirectly promoting metastasis. However, the mechanism underlying chemotherapy-induced metastasis in the course of chemotherapy, and afterwards, remains elusive in pancreatic cancer. In the present study, we aimed to determine the expression of CCL26 in the pancreatic cancer-associated fibroblasts (CAFs) after nab-paclitaxel treatment and to explore the role of CCL26 in the pancreatic adenocarcinoma (PDAC) invasion. Our results showed that nab-paclitaxel increased CCL26 mRNA and protein expression levels in a dose- and time-dependent manner. Subsequently, PDAC cell lines were treated with recombinant CCL26 for 48 h. The transwell migration assay showed that recombinant CCL26 enhanced the invasion of PDAC cells. Western blot analysis showed that the protein expression levels of phospho-(p-)PI3K, p-AKT, and p-mTOR were increased by CCL26 in PDAC cells. CCL26 expressions in 95 PDAC tissues and adjacent normal tissues were evaluated using reverse transcription-quantitative polymerase chain reaction and immunohistochemistry. CCL26 was found to be overexpressed in PDAC samples, and upregulated CCL26 expression was significantly associated with advanced perineural invasion, lymph node metastasis, and poor differentiation. In summary, our results showed that nab-paclitaxel increased the expression of CCL26 in CAFs, and CCL26 enhanced the invasive potential of pancreatic cancer cells by activating the PI3K/AKT/mTOR axis. Thus, CCL26 may be a potential prognostic biomarker for pancreatic cancer.

Up-Regulation of circEIF6 Contributes to Pancreatic Cancer Development Through Targeting miR-557/SLC7A11/PI3K/AKT Signaling.

BackgroundAccruing evidences have pointed out that abnormal expression of circular RNAs (circRNAs) was closely related to the development of many malignancies. The present study intended to disclose the role of circRNA eukaryotic translation initiation factor 6 (circEIF6; hsa_circ_0060055) in pancreatic cancer progression.MethodsQuantitative real-time polymerase chain reaction (qRT-PCR) was conducted to determine the expression of circEIF6, EIF6 messenger RNA (mRNA), microRNA-557 (miR-557) and solute carrier family 7 member 11 (SLC7A11) mRNA. Cell proliferation ability, migration and invasion abilities and apoptosis were evaluated by Cell Counting Kit 8 (CCK8) assay, transwell migration and invasion assays and flow cytometry. Western blot assay was performed for the expression determination of all proteins. The predicted interaction between miR-557 and circEIF6 or SLC7A11 was confirmed by dual-luciferase reporter assay. Xenograft tumor model was used for exploring the biological function of circEIF6 in vivo.ResultsCircEIF6 abundance was aberrantly up-regulated in pancreatic tumor tissues and cell lines. Cell proliferation, migration and invasion were significantly restrained while cell apoptosis was induced with the silencing of circEIF6 in pancreatic cancer cells. CircEIF6 silencing also hampered the activation of phosphatidylinositol 3-kinase (PI3K)/AKT serine/threonine kinase (AKT) pathway. CircEIF6 bound to miR-557, and circEIF6 silencing elevated the expression of miR-557 in pancreatic cancer cells. MiR-557 knockdown partly overturned circEIF6 silencing-induced effects in pancreatic cancer cells. SLC7A11 was a target of miR-557, and miR-557 overexpression suppressed malignant potential of pancreatic cancer cells partly through reducing the expression of SLC7A11. CircEIF6 knockdown blocked xenograft tumor growth in vivo.ConclusionCircEIF6 aggravated pancreatic cancer development through promoting cell proliferation, migration and invasion and suppressing cell apoptosis through targeting miR-557/SLC7A11/PI3K/AKT signaling.

The catalytically defective receptor protein tyrosine kinase EphA10 promotes tumorigenesis in pancreatic cancer cells.

EphA10 (erythropoietin‐producing hepatocellular carcinoma receptor A10) is a catalytically defective receptor protein tyrosine kinase in the ephrin receptor family. Although EphA10 is involved in the malignancy of some types of cancer, its role as an oncogene has not been extensively studied. Here, we investigated the influence of EphA10 on the tumorigenic potential of pancreatic cancer cells. Analysis of expression profiles from The Cancer Genome Atlas confirmed that EphA10 was elevated and higher in tumor tissues than in normal tissues in some cancer types, including pancreatic cancer. EphA10 silencing reduced the proliferation, migration, and adhesion of MIA PaCa‐2 and AsPC‐1 pancreatic cancer cells. These effects were reversed by overexpression of EphA10 in MIA PaCa‐2 cells. Importantly, overexpression and silencing of EphA10 respectively increased and decreased the weight, volume, and number of Ki‐67‐positive proliferating cells in MIA PaCa‐2 xenograft tumors. Further, EphA10 expression was positively correlated with invasion and gelatin degradation in MIA PaCa‐2 cells. Moreover, overexpression of EphA10 enhanced the expression and secretion of MMP‐9 in MIA PaCa‐2 cells and increased the expression of MMP‐9 and the vascular density in xenograft tumors. Finally, expression of EphA10 increased the phosphorylation of ERK, JNK, AKT, FAK, and NF‐κB, which are important for cell proliferation, survival, adhesion, migration, and invasion. Therefore, we suggest that EphA10 plays a pivotal role in the tumorigenesis of pancreatic epithelial cells and is a novel therapeutic target for pancreatic cancer.

Curcumin inhibits pancreatic cancer cell invasion and EMT by interfering with tumor‑stromal crosstalk under hypoxic conditions via the IL‑6/ERK/NF‑κB axis

Hypoxic microenvironment and pancreatic stellate cells (PSCs) play important roles in pancreatic cancer progression. PSCs secrete a number of soluble factors, such as interleukin (IL)‑6, to facilitate cancer metastasis. Our previous study revealed that curcumin inhibited the invasive ability of pancreatic cancer cells by modulating epithelial‑to‑mesenchymal transition (EMT)‑related factors. However, whether curcumin could suppress tumor‑stromal crosstalk in pancreatic cancer and the underlying mechanisms have yet to be fully elucidated. The aim of the present study was to evaluate whether curcumin could affect pancreatic cancer cell invasion and EMT by interfering with tumor‑stromal interaction under hypoxic conditions. The PSCs were treated with curcumin under hypoxic conditions. The activation of PSCs was detected by testing the expression of α‑smooth muscle actin by western blotting and immunofluorescence analysis. The wound healing assay was used to evaluate the migratory potential of PSCs. The secretion and expression of IL‑6 by PSCs was detected by ELISA and reverse transcription‑quantitative PCR (RT‑qPCR) analysis. BxPC‑3 and Panc‑1 cells were treated with PSC‑conditioned media (PSC‑CM), IL‑6, IL‑6‑neutralizing antibody or curcumin under conditions of normoxia or hypoxia. Transwell invasion assay was used to examine the invasive potential of pancreatic cancer cells. The activation of phosphorylated (p‑) extracellular signal‑regulated kinase (ERK) and p‑nuclear factor (NF)‑κB were measured by western blot analysis. The expression of EMT‑related genes at the mRNA and protein levels was detected by RT‑qPCR and western blot analysis, respectively. The results of the present study demonstrated that curcumin inhibited the activation and migration of PSCs under hypoxic conditions. Curcumin also suppressed the secretion and expression of IL‑6 in PSCs. In addition, curcumin and IL‑6‑neutralizing antibody treatment suppressed PSC‑CM‑modulated pancreatic cancer invasion, EMT and the changes in the expression of E‑cadherin, vimentin and matrix metallopeptidase‑9. Furthermore, the increase in the levels of p‑ERK and p‑NF‑κB induced by PSC‑CM could be counterbalanced by both curcumin and IL‑6‑neutralizing antibody treatment under hypoxic conditions. Taken together, these data indicate that curcumin plays an important role in suppressing tumor‑stromal crosstalk and pancreatic cancer metastasis by inhibiting the IL‑6/ERK/NF‑κB axis. Blocking the IL‑6/ERK/NF‑κB axis by curcumin may be a promising therapeutic strategy for the treatment of pancreatic cancer.

Schwann cells support oncogenic potential of pancreatic cancer cells through TGF\u03b2 signaling

Pancreatic ductal adenocarcinoma (PDAC) is one of the solid tumors with the poorest prognosis. The stroma of this tumor is abundant and composed of extracellular matrix and stromal cells (including cancer-associated fibroblasts and immune cells). Nerve fibers invading this stroma represent a hallmark of PDAC, involved in neural remodeling, which participates in neuropathic pain, cancer cell dissemination and tumor relapse after surgery. Pancreatic cancer-associated neural remodeling is regulated through functional interplays mediated by physical and molecular interactions between cancer cells, nerve cells and surrounding Schwann cells, and other stromal cells. In the present study, we show that Schwann cells (glial cells supporting peripheral neurons) can enhance aggressiveness (migration, invasion, tumorigenicity) of pancreatic cancer cells in a transforming growth factor beta (TGFβ)-dependent manner. Indeed, we reveal that conditioned medium from Schwann cells contains high amounts of TGFβ able to activate the TGFβ-SMAD signaling pathway in cancer cells. We also observed in human PDAC samples that high levels of TGFβ signaling activation were positively correlated with perineural invasion. Secretome analyses by mass spectrometry of Schwann cells and pancreatic cancer cells cultured alone or in combination highlighted the central role of TGFβ in neuro-epithelial interactions, as illustrated by proteomic signatures related to cell adhesion and motility. Altogether, these results demonstrate that Schwann cells are a meaningful source of TGFβ in PDAC, which plays a crucial role in the acquisition of aggressive properties by pancreatic cancer cells.

Dual PDK1/Aurora Kinase A Inhibitors Reduce Pancreatic Cancer Cell Proliferation and Colony Formation.

Deregulation of different intracellular signaling pathways is a common feature in cancer. Numerous studies indicate that persistent activation of the phosphoinositide 3-kinase (PI3K) pathway is often observed in cancer cells. 3-phosphoinositide dependent protein kinase-1 (PDK1), a transducer protein that functions downstream of PI3K, is responsible for the regulation of cell proliferation and migration and it also has been found to play a key role in different cancers, pancreatic and breast cancer amongst others. As PI3K is being described to be aberrantly expressed in several cancer types, designing inhibitors targeting various downstream molecules of PI3K has been the focus of anticancer agent development for a long time. In particular, dual inhibitory drugs targeting key signaling molecules in the PI3K pathway have attracted the attention of scientists. Several drugs have progressed to clinical trials, with limited success due to toxicity and bioavailability concerns. Very few anticancer drugs targeting the PI3K pathway have been approved for clinical use and their efficacy is particularly limited towards certain tumors such as pancreatic cancer. Here, we tested two drugs displaying dual inhibitory activity towards PDK1 and Aurora kinase A in a panel of pancreatic cancer cell lines and in two in vivo models of pancreatic cancer. Our data show that both inhibitors are able to impair cell proliferation and clonogenic potential in pancreatic cancer cells. However, the limited activity of both compounds in vivo indicates that further optimization of the pharmacokinetics properties is required.

Targeting Mechanoresponsive Proteins in Pancreatic Cancer: 4-Hydroxyacetophenone Blocks Dissemination and Invasion by Activating MYH14.

Metastasis is complex, involving multiple genetic, epigenetic, biochemical, and physical changes in the cancer cell and its microenvironment. Cells with metastatic potential are often characterized by altered cellular contractility and deformability, lending them the flexibility to disseminate and navigate through different microenvironments. We demonstrate that mechanoresponsiveness is a hallmark of pancreatic cancer cells. Key mechanoresponsive proteins, those that accumulate in response to mechanical stress, specifically nonmuscle myosin IIA (MYH9) and IIC (MYH14), α-actinin 4, and filamin B, were highly expressed in pancreatic cancer as compared with healthy ductal epithelia. Their less responsive sister paralogs-myosin IIB (MYH10), α-actinin 1, and filamin A-had lower expression differential or disappeared with cancer progression. We demonstrate that proteins whose cellular contributions are often overlooked because of their low abundance can have profound impact on cell architecture, behavior, and mechanics. Here, the low abundant protein MYH14 promoted metastatic behavior and could be exploited with 4-hydroxyacetophenone (4-HAP), which increased MYH14 assembly, stiffening cells. As a result, 4-HAP decreased dissemination, induced cortical actin belts in spheroids, and slowed retrograde actin flow. 4-HAP also reduced liver metastases in human pancreatic cancer-bearing nude mice. Thus, increasing MYH14 assembly overwhelms the ability of cells to polarize and invade, suggesting targeting the mechanoresponsive proteins of the actin cytoskeleton as a new strategy to improve the survival of patients with pancreatic cancer. SIGNIFICANCE: This study demonstrates that mechanoresponsive proteins become upregulated with pancreatic cancer progression and that this system of proteins can be pharmacologically targeted to inhibit the metastatic potential of pancreatic cancer cells.