Metastasis Of Human Pancreatic Cancer Research Articles

Abstract 455: Identification of hsa-miR-6794-3p as a key regulatory factor in human pancreatic cancer metastasis

Abstract Metastasis is a major factor in treatment failure in patients with pancreatic cancer, but the underlying mechanisms remain unclear, and new, effective treatment strategies are needed. Here, we sought to identify novel microRNAs (miRNAs) with a key role in pancreatic cancer metastasis. Using a microarray analysis to evaluate miRNA expression in metastatic and non-metastatic pancreatic cancer, we found that expression of the miRNA, hsa-miR-6794-3p, was significantly lower in metastatic pancreatic cancer tissues than in non-metastatic pancreatic cancer tissues. Methylation-specific polymerase chain reaction analyses revealed that hsa-miR-6794-3p expression was downregulated in metastatic pancreatic cancer cells by hypermethylation of CpG islands within the hsa-miR-6794-3p promoter. Gain- and loss-of-function approaches using the human pancreatic cancer cell lines, MIA-PaCa-2 and HPAF-II, expressing low and high levels of hsa-miR-6794-3p, respectively, suggested a role for hsa-miR-6794-3p in decreasing cell invasion, migration, and epithelial-mesenchymal transition (EMT) signaling. Notably, we found that hsa-miR-6794-3p exerts its effects by inhibiting expression of the chromatin remodeling factor, RBBP4, through direct binding to the 3’-untranslated region of its mRNA. The resulting suppression of RBBP4 expression increases levels of the transcription factor GRHL2, which is involved in regulating invasion, migration, and EMT signaling in metastatic pancreatic cancer cells. Thus, lower levels of hsa-miR-6794-3p disrupt GRHL2-mediated regulation of these pathways by disinhibiting expression of the GRHL2 negative regulator, RBBP4. Consistent with these findings, an investigation of the relationship between hsa-miR-6794-3p and clinicopathological features in pancreatic cancer patients using publicly available datasets and immunohistochemistry showed that low levels of hsa-miR-6794-3p are correlated with a poorer prognosis in pancreatic cancer patients. Additional preclinical experiments in nude mice clearly demonstrated that hsa-miR-6794-3p is capable of suppressing pancreatic cancer cell metastasis. Taken together, these results suggest that hsa-miR-6794-3p suppresses tumor metastasis and thus represents a promising prognostic biomarker and therapeutic target in pancreatic cancer. Citation Format: Ha Gyeong Kim, Eun-Taex Oh, Yunmi Cho, Heon Joo Park. Identification of hsa-miR-6794-3p as a key regulatory factor in human pancreatic cancer metastasis [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 455.

Inhibition of Mitochondrial Redox Signaling with MitoQ Prevents Metastasis of Human Pancreatic Cancer in Mice.

Simple SummaryIf improvements of diagnostic techniques and methodologies allow to increasingly detect cancers at the premetastatic stage, metastases still account for about 90% of cancer patient deaths in the clinics. Indeed, there is currently no specific treatment capable of blocking or even delaying the metastatic process. In this context, we previously showed that mitochondria are metabolic sensors initiating the metastatic process. Here, focusing on pancreatic cancer, with which about one-third of patients are diagnosed before the onset of metastases, we report that MitoQ, a mitochondria-targeted antioxidant, interrupts prometastatic redox signaling from mitochondria to the cell body. At doses compatible with the treatment of humans, we found that MitoQ represses pancreatic cancer cell migration, invasion and clonogenicity. It reduced the metastatic homing of human pancreatic cancer cells in mice by about 50%. If applied to patients, metastasis prevention with MitoQ could increase the chances of curing cancer with conventional treatments.At diagnosis, about 35% of pancreatic cancers are at the locally invasive yet premetastatic stage. Surgical resection is not a treatment option, leaving patients with a largely incurable disease that often evolves to the polymetastatic stage despite chemotherapeutic interventions. In this preclinical study, we hypothesized that pancreatic cancer metastasis can be prevented by inhibiting mitochondrial redox signaling with MitoQ, a mitochondria-targeted antioxidant. Using four different cancer cell lines, we report that, at clinically relevant concentrations (100–500 nM), MitoQ selectively repressed mesenchymal pancreatic cancer cell respiration, which involved the inhibition of the expression of PGC-1α, NRF1 and a reduced expression of electron-transfer-chain complexes I to III. MitoQ consequently decreased the mitochondrial membrane potential and mitochondrial superoxide production by these cells. Phenotypically, MitoQ further inhibited pancreatic cancer cell migration, invasion, clonogenicity and the expression of stem cell markers. It reduced by ~50% the metastatic homing of human MIA PaCa-2 cells in the lungs of mice. We further show that combination treatments with chemotherapy are conceivable. Collectively, this study indicates that the inhibition of mitochondrial redox signaling is a possible therapeutic option to inhibit the metastatic progression of pancreatic cancer.

Downregulation of MiD49 contributes to tumor growth and metastasis of human pancreatic cancer.

Changes in mitochondrial morphology by dysregulated mitochondrial fission-fusion proteins have been increasingly recognized as a hallmark of cancer. MiD49 (mitochondrial dynamics protein of 49 kDa) is a newly identified mitochondrial fission protein involved in the dynamic regulation of mitochondrial morphology. However, the expression pattern and biological functions of MiD49 in human cancers remain largely unexplored, especially in pancreatic cancer (PC). In the present study, the expression and clinical significance of MiD49 was firstly determined by RT-qPCR and western blot analyses in PC cell lines and tumor tissues. In addition, the biologic functions of MiD49 in PC cell growth and metastasis were investigated using gain- and loss-of-function assays both in vitro and in vivo. Moreover, the underlying mechanisms by which MiD49 regulates PC cell growth and metastasis were further explored. Our results showed that MiD49 was markedly downregulated in both PC cell lines and human PC specimens. Forced expression of MiD49 suppressed PC cell growth and metastasis both in vitro and in vivo, while knockdown of MiD49 exhibited the opposite effect. Mechanistic exploration demonstrated that the tumor-suppressive effect of MiD49 was mediated by decreased mitochondrial fission and subsequent reduced ROS production in PC cells. Our findings suggest a critical tumor-suppressive role played by MiD49 in pancreatic cancer.

Therapeutic effects and anti-metastasis effects of cationic liposomes against pancreatic cancer metastasis in vitro and in vivo

The anti-metastatic effects of cationic liposomes (CL) composed of 87 mol% dimyristoylphosphatidylcholine (DMPC), 8 mol% O,O′-ditetradecanoyl-N-(α–trimethylammonioacetyl) diethanolamine chloride (2C14ECl) and 5 mol% polyoxyethylene(21) dodecyl ether (C12(EO)21) was investigated for human pancreatic cancer (BxPC-3) cells. The inhibitory effect of CL on the migration of BxPC-3 cells was observed based on a wound scratch assay. CL suppressed pseudopodium formation of BxPC-3 cells. The anti-invasive effect of CL against BxPC-3 cells was observed via a Matrigel invasion assay. The anti-invasive effect of CL for BxPC-3 cells was found to occur through the inhibition of MMP2, MMP9, and MMP14. Overall, the results of this study revealed for the first time, the therapeutic effects and anti-metastasis activity of CL in xenograft mouse models for peritoneal metastasis of human pancreatic cancer.

Photodynamic diagnosis of peritoneal metastasis in human pancreatic cancer using 5-aminolevulinic acid during staging laparoscopy.

Peritoneal metastasis is an important prognostic factor for pancreatic cancer. The present study evaluated the possibility of diagnosing peritoneal metastasis by a photodynamic diagnosis using 5-aminolevulinic acid (5-ALA-PDD). In vitro, protoporphyrin IX (PpIX) accumulation was examined in the AsPC-1-GFP cell line following 5-ALA hydrochloride administration. In vivo, AsPC-1-GFP cells were injected into the peritoneal cavities of mice. Three weeks later 5-ALA hydrochloride was intraperitoneally administered to the mice. The peritoneal nodules were observed under fluorescence excitation. A total of 34 patients were enrolled in the present study who were clinically diagnosed with pancreatic malignancy. 5-ALA hydrochloride was orally administered to the patients prior to surgery. During the operation the abdominal cavity was observed under white light and fluorescence. In vitro and in vivo, it was confirmed that PpIX-induced red fluorescence. In 9 patients peritoneal nodules suspected to be peritoneal metastasis were observed under white light. In 4 of the 9 patients nodules were detected on the basis of the fluorescence images. Fluorescent nodules were histopathologically diagnosed as metastatic. In the present study it was confirmed that 5-ALA-PDD holds promise for the rapid diagnosis of peritoneal metastasis in patients with pancreatic cancer.

RUNX3 as a Potential Predictor of Metastasis in Human Pancreatic Cancer.

In genetically engineered murine models of pancreatic ductal adenocarcinomas (PDAC), high levels of Runx3 increase the metastatic potential of cancer cells. In this study we evaluated the role of Runx3 in human pancreatic cancer. Runx3 was retrospectively assessed by immunohistochemistry in seventy-eight tumor samples of patients who underwent surgical resection for PDCA and were followed at least for 24 months. Thirty-two cases resulted completely negative for Runx3; forty-six showed highly variable expression. We established an optimal cut-off value of Runx3 in predicting distant metastasis equal to 0.04. The odds ratio (ORs) for development of distant metastases at multivariate analysis for patients having Runx3 ≥0.04 was 4.26 (p=0.043) and 4.68 (p=0.032) after adjusting for residual tumor and treatment, respectively; OR for development of metastases in multiple sites was 4.28 (p=0.025) for Runx3 ≥0.04. Our results support the ability of Runx3 to contribute to the dissemination of human PDAC thus confirming the observations from murine models.

The role and mechanism of capping actin protein of muscle Z-line alpha subunit 1 in invasion and metastasis of human pancreatic cancer

Objective To observe the expression of capping actin protein of muscle Z-line alpha subunit 1 (CAPZA1) in pancreatic cancer and its relationship with prognosis, and explore the role and mechanism of CAPZA1 in regulating the invasion and metastasis of pancreatic cancer cells. Methods Immunohistochemistry was used to detect the expression of CAPZA1 and epithelial-mesenchymal transition (EMT) markers in pancreatic cancer tissues. The statistical analysis was made on the prognosis of patients with pancreatic cancer. Western blotting and real-time reverse transcriptase-polymerase chain reaction (RT-qPCR) were used to detect the expression of CAPZA1 and EMT markers in pancreatic cancer cells. Transwell, and cell counting kit-8 (CCK-8) were used to detect migration, invasion and proliferation of pancreatic cancer cells. Results The expression of CAPZA1 was negatively correlated with the biological characteristics of pancreatic cancer cells and the prognosis of patients. The expression of CAPZA1 was negatively correlated with the invasion and metastasis potentials of pancreatic cancer cells. Inhibition of CAPZA1 expression could promote the invasion and metastasis of pancreatic cancer cells (192.0±13.8 vs. 153.0±17.1, P=0.004), while over-expression of CAPZA1 could inhibit the invasion and metastasis of pancreatic cancer cells (107.0±18.5 vs. 153.0±17.1, P=0.004). The expression of CAPZA1 was correlated with the expression of EMT markers E-cadherin (0.76±0.09 vs. 0.57±0.14, P=0.034), N-cadherin (0.53±0.12 vs. 0.74±0.10, P=0.017) and Vimentin (0.56±0.20 vs. 0.93±0.19, P=0.017). Conclusion CAPZA1 can inhibit the EMT of pancreatic cancer cells and reduce the invasion ability of them0 by regulating the assembly of cell skeleton. Key words: Pancreatic cancer; Capping actin protein of muscle Z-line alpha subunit 1; Cell skeleton; Invasion; Epithelial-mesenchymal transition

Nestin phosphorylation at threonines 315 and 1299 correlates with proliferation and metastasis of human pancreatic cancer.

The neuroepithelial stem cell marker nestin is a cytoskeletal protein that regulates cell proliferation, invasion, and stemness in various tumors, including pancreatic tumors. In the present study, we examined the expression and roles of phosphorylated nestin in pancreatic cancer cells. Nestin phosphorylation at threonines 315 (Thr315) and 1299 (Thr1299) was observed during mitosis in human pancreatic cancer cells. Nestin phosphorylation was positively correlated with a cell proliferation marker, MIB‐1 expression in human pancreatic cancer samples. Transfection of MIA PaCa‐2 cells with nestin mutated at Thr315 and/or Thr1299 (to suppress phosphorylation) resulted in lower proliferation rates than those in control groups. Transfecting MIA PaCa‐2 cells with wild‐type nestin or with nestin mutated at Thr315 increased migration and invasion. In contrast, transfection with nestin mutated at both phosphorylation sites (Thr315 and Thr1299) did not enhance cell migration or invasion. In an intra‐splenic xenograft experiment using MIA PaCa‐2 cells, tumors expressing the nestin double mutant formed fewer liver metastases than tumors expressing wild‐type nestin. Nestin phosphorylation at these two sites was decreased upon treatment with inhibitors for cyclin dependent kinases, AKT, and Aurora in PANC‐1 cells, which express a high baseline level of phosphorylated nestin. These findings suggest that phosphorylation of nestin at Thr315 and/or Thr1299 affects cell proliferation, and inhibition of both phosphorylation sites suppresses invasion and metastasis of human pancreatic cancer. Inhibiting nestin phosphorylation at these two sites may represent a novel therapeutic strategy for pancreatic cancer.

Abstract B63: An effective new strategy to control and inhibit the “undruggable” oncogenic K-RAS hyperactivation in human pancreatic cancer

Abstract Hyperactive K-RAS signaling is a major menace that drives aggressive cancer cell dissemination, tumor progression and metastasis in human pancreatic cancer. Currently, there are no effective therapies to control human pancreatic cancers that have metastasized and oncogenic K-RAS mutations reman “undruggable” in the clinics. Therefore, counteracting K-RAS hyperactivation in attempt to reverse malignant transformation and inhibit latent tumor spread is an important goal in pancreatic cancer biology and major challenge in targeted therapy development in pancreatic cancer. Instead of targeting an upstream signaling module such as EGFR/K-RAS/B-RAF/MEK/MAPK/ERK/AKT/mTOR, we targeted the most downstream signaling module in the K-RAS signaling pathway called the SIAH-dependent proteolytic machinery. SIAHs are the human homologs of Seven-In-Absentia (SINA), an evolutionarily conserved RING E3 ligase, an essential downstream signaling module and a critical “gatekeeper” required for proper K-RAS signal transduction. Guided by studies in Drosophila, SIAH (seven-in-absentia homologue), the most downstream gatekeeper required for proper RAS signaling and tumor cell survival, was identified as a suitable and new drug target for anti-K-RAS and anticancer therapy. We found that inhibiting SIAH function is highly effective to abolish well-established and late-stage pancreatic tumor growth and metastasis in our pre-clinical studies. Thus, we have identified a new vulnerability, SIAH E3 ligase, in the oncogenic K-RAS signaling pathway in pancreatic cancer. These findings demonstrate that SIAH is indeed an attractive, logical and potent anti-K-RAS therapeutic target for us to develop new and effective anticancer strategy against human pancreatic cancer. Through our work, SIAH has emerged as a new and effective drug target against oncogenic K-RAS hyperactivation in human pancreatic cancer. As one of the most evolutionarily conserved E3 ligases, SIAH is ideally and logically positioned to become a next-generation anti-K-RAS drug target in human pancreatic cancer. Our preclinical results have demonstrated that “SIAH-dependent proteolysis” is indeed an Achilles’ heel for human pancreatic cancer cells. Hence, anti-SIAH-based small molecule inhibitors may aid in expanding our arsenal of novel anticancer therapies in pancreatic cancer. By attacking the most downstream “gatekeeper” critical for the proper oncogenic K-RAS signaling transmission, we may be in a position to halt the genesis, progression and metastasis of the most aggressive and the deadliest forms of human pancreatic cancer in the future. We aim to translate these exciting findings to the cancer clinics to benefit our pancreatic cancer patients with metastatic diseases in the future. Citation Format: Amy H. Tang, Minglei Bian, Vasilena Zheleva, Monicah M. Njogu, Justin J. Odanga, Roger R. Perry, Richard A. Hoefer, Bruce E. Knudsen.{Authors}. An effective new strategy to control and inhibit the “undruggable” oncogenic K-RAS hyperactivation in human pancreatic cancer. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2016 May 12-15; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(24 Suppl):Abstract nr B63.

Potential involvement of IQGAP1 in proliferation and metastasis of human pancreatic cancer.

IQGAP1, as a scaffold protein, integrates diverse cellular functions, including rearrangement of the actin cytoskeleton, cell adhesion, gene transcription and cell cycle regulation. IQGAP1 is elevated in a number of human cancer cells. However little is known about the expression of IQGAP in human pancreatic cancer and its association with cancer proliferation or metastasis. In the present study, we examined the expression of IQGAP1 in different pancreatic cancer cell lines and we found that IQGAP1 level is highly correlated with the degree of malignancy of pancreatic cancer cell metastasis. The proliferation, metastasis, motility and tumorigenesis in SW1990 human pancreatic cells were greatly impaired by down-regulating IQGAP1 expression with RNA interference. Mechanistic analysis indicated that Cdc42/Rac1 pathway might contribute to IQGAP1-mediated-pancreatic cell proliferation and tumorigenesis.

Abstract B70: Developing a new and potent anti-K-RAS strategy by inhibiting SIAH E3 ligase, the most downstream “gatekeeper” in the oncogenic K-RAS signal pathway, to block well-established pancreatic tumor growth

Abstract Hyperactive K-RAS signaling is a major menace that drives aggressive cancer cell dissemination, tumor progression and metastasis in human pancreatic cancer. Currently, there are no effective therapies to control human pancreatic cancers that have oncogenic K-RAS mutations that confer drug resistance, aggressive tumor growth, systemic metastasis and poor clinical outcome. Therefore, finding novel approaches and new drug targets to inhibit oncogenic K-RAS activation is an urgent goal and major challenge in targeted therapy development in pancreatic cancer. Instead of targeting an upstream signaling module such as EGFR/K-RAS/B-RAF/MEK/MAPK/ERK/AKT/mTOR, we targeted the most downstream signaling module in the K-RAS signaling pathway called the SIAH-dependent proteolytic machinery. SIAHs are the human homologs of Seven-In-Absentia (SINA), an evolutionarily conserved RING E3 ligase, an essential downstream signaling module and a critical “gatekeeper” required for proper K-RAS signal transduction. Guided by the insights and principles learned from Drosophila RAS signaling pathway, we have conducted preclinical studies to dissect SIAH function in the context of K-RAS-mediated tumorigenesis and metastasis in human pancreatic cancer cells and tumor specimens. We found that inhibiting SIAH function is highly effective to abolish well-established and late-stage pancreatic tumor growth and metastasis in our pre-clinical studies. These findings demonstrate that SIAH is indeed an attractive, logical and potent anti-K-RAS therapeutic target for us to develop new and effective anticancer strategy against human pancreatic cancer. Through our work, SIAH has emerged as a new and effective drug target against oncogenic K-RAS hyperactivation in human pancreatic cancer. As one of the most evolutionarily conserved E3 ligases, SIAH is ideally and logically positioned to become a next-generation anti-K-RAS drug target in human cancer. Our preclinical studies have demonstrated that “SIAH-dependent proteolysis” is indeed an Achilles’ heel for human pancreatic cancer cells. Hence, anti-SIAH-based small molecule inhibitors may aid in expanding our arsenal of novel anticancer therapies in pancreatic cancer. By attacking the most downstream “gatekeeper” critical for the proper oncogenic ERBB/K-RAS signaling transmission, we may be in a position to halt the genesis, progression and metastasis of the most aggressive and the deadliest forms of human pancreatic cancer in the future. Citation Format: Vasilena Zheleva, Minglei Bian, Xiaofei Gao, Justin J. Odanga, Monicah M. Njogu, Zena M. Urban, Bruce E. Knudsen, Richard A. Hoefer, Roger R. Perry, Amy H. Tang. Developing a new and potent anti-K-RAS strategy by inhibiting SIAH E3 ligase, the most downstream “gatekeeper” in the oncogenic K-RAS signal pathway, to block well-established pancreatic tumor growth. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr B70.

Gd-Metallofullerenol Nanomaterial Suppresses Pancreatic Cancer Metastasis by Inhibiting the Interaction of Histone Deacetylase 1 and Metastasis-Associated Protein 1.

The treatment of pancreatic cancer frequently fails due to local recurrence and hepatic metastasis. Our previous study found that Gd@C82(OH)22 can suppress pancreatic cancer by inhibiting MMP-2/9 expression. In this study, we further explored the epigenetic mechanism of Gd@C82(OH)22 in human pancreatic cancer metastasis. Gd@C82(OH)22 suppressed tumor metastasis through down-regulation of metastasis-associated protein 1 (MTA1), HDAC1, HIF-1α, and MMP-2/9 and up-regulation of reversion-cysteine protein with the Kazal motif (RECK). The level of acetylation was increased in the promoter region of the RECK gene after Gd@C82(OH)22 treatment. The interaction of MTA1, HDAC1, and HIF-1α was inhibited by Gd@C82(OH)22. Furthermore, large-scale molecular dynamics simulations revealed Gd@C82(OH)22 could serve as an effective HDAC inhibitor to the protein-protein association between HDAC1 and MTA1, especially through MTA1's SANT and ELM2 dimerization domains. Our findings implicate Gd@C82(OH)22 as a novel HDAC inhibitor acting to increase RECK expression by suppressing the MTA1/HDAC1 co-repressor complex. Gd@C82(OH)22 may serve as a potential HDAC1 inhibitor to suppress pancreatic cancer cell invasion and metastasis both in vitro and in vivo. According to computer analysis and experimental validation, Gd@C82(OH)22 activates RECK expression by inhibiting the interaction of HDAC1 and MTA1.

Leptin signaling enhances cell invasion and promotes the metastasis of human pancreatic cancer via increasing MMP-13 production.

Emerging evidence has suggested that leptin, an adipokine related to energy homeostasis, plays a role in cancer growth and metastasis. However, its impact on pancreatic cancer is rarely studied. In this study, we found that leptin's functional receptor Ob-Rb was expressed in pancreatic cancer cell lines. Treatment with leptin enhanced the migration and invasion of pancreatic cancer cells but did not affect the proliferation of human pancreatic cancer cells. Leptin up-regulated the expression of matrix metalloproteinase-13 (MMP-13) via the JAK2/STAT3 signaling pathway. The overexpression of leptin was shown to significantly promote tumor growth and lymph node metastasis in a subcutaneous model and an orthotopic model of human pancreatic cancer, respectively. Furthermore, in human pancreatic cancer tissues, the expression of Ob-Rb was positively correlated with the MMP-13 level. The increased expression of either Ob-Rb or MMP-13 was significantly associated with lymph node metastasis and tended to be associated with the TNM stage in patients with pancreatic cancer. Our findings suggest that leptin enhances the invasion of pancreatic cancer through the increase in MMP-13 production, and targeting the leptin/MMP-13 axis could be an attractive therapeutic strategy for pancreatic cancer.

Abstract 3130: Zoledronic acid inhibits proliferation and metastasis of human pancreatic cancer in the patient-derived orthotopic xenograft (PDOX) model by targeting tumor-educated macrophages

Abstract Macrophages harvested from the peritoneal cavity of nude mice with subcutaneous human pancreatic tumors were defined as “tumor-educated macrophages” (EMϕ) and macrophages harvested from mice without tumors were defined as “naïve macrophages” (NMϕ). EMϕ promote tumor growth and metastasis. The aim of the present study was to determine the efficacy of Zoledronic acid (ZA) on EMϕ in a pancreatic cancer patient derived orthotopic xenograft (PDOX) nude mouse model. In this study, EMϕ and NMϕ were compared for their ability to enhance tumor progression. We initially demonstrated that the cancer cells exposed to the conditioned medium harvested from EMϕ culture significantly increased proliferation (p = 0.016) and had more migration stimulation capability (p < 0.001) compared to cultured cancer cells treated with the conditioned medium from NMϕ. Next, we examined the efficacy of ZA on EMϕ, and NMϕ and found that ZA had the ability to kill both EMϕ and NMϕ in vitro. We then demonstrated that EMϕ promoted tumor growth and metastasis in an orthotopic mouse model of a human pancreatic cancer cell line, ZA reduced the tumor growth (p = 0.006) and metastasis (p = 0.025) promoted by EMϕ. Finally, we examined the efficacy of ZA for pancreatic cancer in the PDOX model, and found that the combination of gemcitabine (GEM) and ZA reduced tumor weight (p = 0.016) and tumor growth (p = 0.005) compared to GEM alone. ZA alone reduced metastasis (p = 0.009). These results suggest that ZA inhibits the proliferation and the metastasis of human pancreatic cancer by targeting EMϕ. Citation Format: Yukihiko Hiroshima, Mohamed K. Hassenein, Rhiana Menen, Matthew H.g. Katz, Jason B. Fleming, Sho Sato, Takashi Murakami, Mako Yamamoto, Fuminari Uehara, Shinji Miwa, Shuya Yano, Masashi Momiyama, Ali Maawy, Takashi Chishima, Kuniya Tanaka, Michael Bouvet, Itaru Endo, Robert M. Hoffman. Zoledronic acid inhibits proliferation and metastasis of human pancreatic cancer in the patient-derived orthotopic xenograft (PDOX) model by targeting tumor-educated macrophages. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3130. doi:10.1158/1538-7445.AM2014-3130

CXCR4 promotes GSK3β expression in pancreatic cancer cells via the Akt pathway.

CXCR4 and glycogen synthase kinase-3β (GSK3β) promote proliferation and invasion of pancreatic cancer. Inhibition of CXCR4 suppresses GSK3β expression. However, the molecular mechanism by which CXCR4 contributes to human pancreatic cancer metastasis is not completely understood. In this study, therefore, we analyzed the effect of CXCR4 on GSK3β expression and its molecular mechanism. PANC-1 and SW-1990 cells were used in this study. PANC-1 and SW-1990 cell lines which stably expressed upregulated or downregulated CXCR4 were used for further study. Western blotting was employed to detected the expression of CXCR4, GSK3β and MMP-2. Cell invasion assay was used to detect the effect of the Akt pathway on CXCR4-induced GSK3β expression. Overexpression of CXCR4 promoted GSK3β expression and silencing of CXCR4 suppressed GSK3β expression. Overexpression of CXCR4 activated cyclin D1 and p-Akt expression, but inhibited p21 expression. Silencing of CXCR4 had the reverse effect. CXCR4 promoted GSK3β expression and PANC-1 invasion by Akt signaling. CXCR4 upregulated GSK3β expression, at least in part, at the level of transcription. CXCR4 promotes GSK3β expression via the Akt cell signaling pathway in pancreatic cancer cells.

The tumor-educated-macrophage increase of malignancy of human pancreatic cancer is prevented by zoledronic acid.

We previously defined macrophages harvested from the peritoneal cavity of nude mice with subcutaneous human pancreatic tumors as “tumor-educated-macrophages” (Edu) and macrophages harvested from mice without tumors as “naïve-macrophages” (Naïve), and demonstrated that Edu-macrophages promoted tumor growth and metastasis. In this study, Edu- and Naïve-macrophages were compared for their ability to enhance pancreatic cancer malignancy at the cellular level in vitro and in vivo. The inhibitory efficacy of Zoledronic acid (ZA) on Edu-macrophage-enhanced metastasis was also determined. XPA1 human pancreatic cancer cells in Gelfoam co-cultured with Edu-macrophages proliferated to a greater extent compared to XPA1 cells cultured with Naïve-macrophages (P = 0.014). XPA1 cells exposed to conditioned medium harvested from Edu culture significantly increased proliferation (P = 0.016) and had more migration stimulation capability (P<0.001) compared to cultured cancer cells treated with the conditioned medium from Naïve. The mitotic index of the XPA1 cells, expressing GFP in the nucleus and RFP in the cytoplasm, significantly increased in vivo in the presence of Edu- compared to Naïve-macrophages (P = 0.001). Zoledronic acid (ZA) killed both Edu and Naïve in vitro. Edu promoted tumor growth and metastasis in an orthotopic mouse model of the XPA1 human pancreatic cancer cell line. ZA reduced primary tumor growth (P = 0.006) and prevented metastasis (P = 0.025) promoted by Edu-macrophages. These results indicate that ZA inhibits enhanced primary tumor growth and metastasis of human pancreatic cancer induced by Edu-macrophages.

Increased B Cell-Activating Factor Promotes Tumor Invasion and Metastasis in Human Pancreatic Cancer

B cell-activating factor (BAFF) is a cytokine belonging to the tumor necrosis factor (TNF) superfamily. It has been reported that BAFF is elevated in patients with autoimmune pancreatitis and contributes to the malignant potential of blood cancers and solid tumors. In this study, clinical evidence of increased BAFF levels in patients with pancreatic ductal adenocarcinoma (PDAC) was obtained, and the roles and mechanisms of BAFF in PDAC were clarified in human tissues of PDAC and from in vitro data of PDAC cell lines. Serum levels of BAFF in patients with PDAC were significantly higher than in healthy subjects (p = 0.0121). Patients with UICC stage IV PDAC (T1-4, N0-1, M1) had significantly higher levels of serum BAFF compared to patients with PDAC (p = 0.0182). BAFF was remarkably expressed in infiltrating B lymphocytes surrounding pancreatic cancer in human pancreatic tissues, suggesting that BAFF may play a role in progression of pancreatic cancer. PDAC cell lines were cultured with human recombinant BAFF, and morphology and gene expression were analyzed; pancreatic cancer cells changed to a fibroblast-like morphology, and showed altered gene expression of E-cadherin, vimentin and Snail. These BAFF-induced changes reflect enhanced cell motility and invasion. BAFF-R-overexpressing cell clones confirmed the association between these BAFF-induced changes and epithelial-mesenchymal transition (EMT)-related genes. BAFF was elevated in patients with metastatic advanced PDAC and induced alterations in PDAC cells via regulation of EMT-related genes. Elucidation of the precise role and mechanism of control of BAFF may lead to new therapeutic approaches with the aim of improving pancreatic cancer survival.

Molecular markers associated with outcome and metastasis in human pancreatic cancer

BackgroundPancreatic ductal adenocarcinoma (PDAC) is a heterogeneous cancer in which differences in survival rates might be related to a variety in gene expression profiles. Although the molecular biology of PDAC begins to be revealed, genes or pathways that specifically drive tumour progression or metastasis are not well understood.MethodsWe performed microarray analyses on whole-tumour samples of 2 human PDAC subpopulations with similar clinicopathological features, but extremely distinct survival rates after potentially curative surgery, i.e. good outcome (OS and DFS > 50 months, n = 7) versus bad outcome (OS < 19 months and DFS < 7 months, n = 10). Additionally, liver- and peritoneal metastases were analysed and compared to primary cancer tissue (n = 11).ResultsThe integrin and ephrin receptor families were upregulated in all PDAC samples, irrespective of outcome, supporting an important role of the interaction between pancreatic cancer cells and the surrounding desmoplastic reaction in tumorigenesis and cancer progression. Moreover, some components such as ITGB1 and EPHA2 were upregulated in PDAC samples with a poor outcome, Additionally, overexpression of the non-canonical Wnt/β-catenin pathway and EMT genes in PDAC samples with bad versus good outcome suggests their contribution to the invasiveness of pancreatic cancer, with β-catenin being also highly upregulated in metastatic tissue.ConclusionsComponents of the integrin and ephrin pathways and EMT related genes, might serve as molecular markers in pancreatic cancer as their expression seems to be related with prognosis.

Targeting FGFR/PDGFR/VEGFR Impairs Tumor Growth, Angiogenesis, and Metastasis by Effects on Tumor Cells, Endothelial Cells, and Pericytes in Pancreatic Cancer

Activation of receptor tyrosine kinases, such as fibroblast growth factor receptor (FGFR), platelet-derived growth factor receptor (PDGFR), and VEGF receptor (VEGFR), has been implicated in tumor progression and metastasis in human pancreatic cancer. In this study, we investigated the effects of TKI258, a tyrosine kinase inhibitor to FGFR, PDGFR, and VEGFR on pancreatic cancer cell lines (HPAF-II, BxPC-3, MiaPaCa2, and L3.6pl), endothelial cells, and vascular smooth muscle cells (VSMC). Results showed that treatment with TKI258 impaired activation of signaling intermediates in pancreatic cancer cells, endothelial cells, and VSMCs, even upon stimulation with FGF-1, FGF-2, VEGF-A, and PDGF-B. Furthermore, blockade of FGFR/PDGFR/VEGFR reduced survivin expression and improved activity of gemcitabine in MiaPaCa2 pancreatic cancer cells. In addition, motility of cancer cells, endothelial cells, and VSMCs was reduced upon treatment with TKI258. In vivo, therapy with TKI258 led to dose-dependent inhibition of subcutaneous (HPAF-II) and orthotopic (L3.6pl) tumor growth. Immunohistochemical analysis revealed effects on tumor cell proliferation [bromodeoxyuridine (BrdUrd)] and tumor vascularization (CD31). Moreover, lymph node metastases were significantly reduced in the orthotopic tumor model when treatment was initiated early with TKI258 (30 mg/kg/d). In established tumors, TKI258 (30 mg/kg/d) led to significant growth delay and improved survival in subcutaneous and orthotopic models, respectively. These data provide evidence that targeting FGFR/PDFGR/VEGFR with TKI258 may be effective in human pancreatic cancer and warrants further clinical evaluation.

Expression of Slug in pancreatic cancer and inhibitory effects of anti-Slug on invasion and migration of pancreatic carcinoma cells

Objective To investigate expression of slug and E-cadherin in pancreatic cancer tissues and determine the inhibitory effects of anti-Slug, an anti-sense plasmid, on the invasion of pancreatic cancer cell lines in vitro. Methods Slug and E-cadherin protein and mRNA was analyzed by IHP and RT-PCR in 36 cases of pancreatic cancer. Then anti-Slug plasmid was transfected into herin and Slug expression. The inhibitory effects of anti-sense Slug were also detected by Transwell motility assay and Matrigel invasion assay. Results The expression of Slug and mRNA in metastatic pancreatic cancer tissue was higher than that in non-metastatic tissue. E-cadherin and mRNA was lower in metastasis tissues(P＜0.05). The inverse relationships were further observed by transient transfection of anti-Slug into SW1990H4 cells. The downregulated expression of Slug and re-expression of E-cadherin were found. The Slug mRNA levels were 0.985±0.016,0.973±0.014, 0. 554±0. 011 after 0, 48 h of transfection of anti-sense Slug, and that of E-cadherin were 0.120±0.001, 0.360±0.002, 0. 727±0. 006, respectively. The diference was significant between different time points (P＜0.05). The Slug mRNA levels were 0. 206±0.017, 0.968±0.015, and that of E-cadherin were 0. 18±0.002,0.727±0.006 after stable transfection of anti-sense Slug, and control plasmid, respectively. The diference was significant (P＜0.05). The motility activity(393±28, 352±24, 96 ±13 )and the invasion activity (223 ± 69, 202 ± 64, 65 ±19) of1 antisense Slug transfectant cells were significantly decreased as compared with those of control cells (P＜0.05). Conclusions Higher expression of slug and lower expression of E-cadherin is related to the invasion and metastasis in pancreatic cancer. A reverse corelation of E-cadherin and Slug expression exists in pancreatic cancer. Slug is possibly a potential target for cancer gene therapy blocking invasion and metastasis in human pancreatic cancer. Key words: Pancreatic carcinoma; Slug; Cadherins; Transfection; Metastasis