Downregulation of the DNA Repair Gene DDB2 by Arecoline Is through p53's DNA-Binding Domain and Is Correlated with Poor Outcome of Head and Neck Cancer Patients with Betel Quid Consumption

Arecoline is the principal alkaloid in the areca nut, a component of betel quids (BQs), which are carcinogenic to humans. Epidemiological studies indicate that BQ-chewing contributes to the occurrence of head and neck cancer (HNC). Previously, we have reported that arecoline (0.3 mM) is able to inhibit DNA repair in a p53-dependent pathway, but the underlying mechanism is unclear. Here we demonstrated that arecoline suppressed the expression of DDB2, which is transcriptionally regulated by p53 and is required for nucleotide excision repair (NER). Ectopic expression of DDB2 restored NER activity in arecoline-treated cells, suggesting that DDB2 downregulation was critical for arecoline-mediated NER inhibition. Mechanistically, arecoline inhibited p53-induced DDB2 promoter activity through the DNA-binding but not the transactivation domain of p53. Both NER and DDB2 promoter activities declined in the chronic arecoline-exposed cells, which were consistent with the downregulated DDB2 mRNA in BQ-associated HNC specimens, but not in those of The Cancer Genome Atlas (TCGA) cohort (no BQ exposure). Lower DDB2 mRNA expression was correlated with a poor outcome in HNC patients. These data uncover one of mechanisms underlying arecoline-mediated carcinogenicity through inhibiting p53-regulated DDB2 expression and DNA repair.

Expression of HIF-1α and VEGF in feline mammary gland carcinomas: association with pathological characteristics and clinical outcomes

Background

The microenvironment within solid malignant tumors, including feline mammary gland carcinomas (FMGCs), is commonly hypoxic, possibly due to the lack of functional blood vessels in rapidly proliferating neoplastic tissue. Malignant cells can undergo genetic and adaptive changes that prevent them from dying due to oxygen deprivation through expressions of hypoxia-inducible factor 1 alpha (HIF-1α) and vascular endothelial growth factor (VEGF). Therefore, HIF-1α and VEGF are ideal biomarkers for cancer therapy and prognostic evaluation. The aims of this study were to evaluate the expression of HIF-1α and VEGF in feline mammary carcinomas and analyze their correlations with clinical and pathological factors, such as clinical stage, histologic grading, regional metastasis, and overall survival rate.

Results

Paraffin-embedded tissue samples collected from 72 cats with FMGCs were retrospectively studied. Histologic pattern and histologic grading (Elston and Ellis grading system) of these FMGCs were determined. Our data indicated that grade II tubulopapillary carcinomas (43/72, 59.7%) prevailed in this study, and most FMCGs showed apparent necrosis, squamous metaplasia, and intratumoral stromal response. According to the results of immunohistochemical (IHC) stainings performed in tissue microarrays (TMAs), HIF-1α and VEGF overexpressions were respectively noted in 69.4% (50/72) and 77.8% (56/72) of FMGC cases. Chi-square test showed no correlation of HIF-1α overexpression with clinical and pathological factors. VEGF overexpression was significantly correlated with histologic pattern (p = 0.021), stromal response (p = 0.048), squamous metaplasia (p = 0.001), and lymphovascular invasion (p = 0.007). However, neither HIF-1α nor VEGF overexpression was correlated with histologic grading and metastasis. Of 38 cats with 1-year follow-up, IHC stainings of HIF-1α and VEGF were performed on whole tissue sections. The results showed that overexpression of HIF-1α was significantly correlated with the overall survival rate (p < 0.05) (log-rank test), whereas there was no significant correlation between VEGF overexpression and overall survival rate.

Conclusions

This study suggests that the overexpression of HIF-1α may indicate poor prognosis/overall survival rate in cats with FMGCs. Developing compounds that inhibit HIF-1α may be a potential approach to FMGC treatment.

Three-dimensional image simulation of primary diaphragmatic hemangioma: A case report

BACKGROUND

Fewer than 200 cases of diaphragmatic tumors have been reported in the past century. Diaphragmatic hemangiomas are extremely rare. Only nine cases have been reported in English literature to date. We report a case of cavernous hemangioma arising from the diaphragm. Pre-operative three-dimensional (3D) simulation and minimal invasive thoracoscopic excision were performed successfully, and we describe the radiologic findings and the surgical procedure in the following article.

CASE SUMMARY

A 40-year-old man was referred for further examination of a mass over the right basal lung without specific symptoms. Contrast-enhanced computed tomography revealed a poorly-enhanced lesion in the right basal lung, abutting to the diaphragm, measuring 3.1 cm × 1.5 cm in size. The mediastinum showed a clear appearance without evidence of abnormal mass or lymphadenopathy. A preoperative 3D image was reconstructed, which revealed a diaphragmatic lesion. Video-assisted thoracic surgery was performed, and a red papillary tumor was found, originating from the right diaphragm. The tumor was resected, and the pathological diagnosis was cavernous hemangioma.

CONCLUSION

In this rare case of diaphragmatic hemangioma, 3D image simulation was helpful for the preoperative evaluation and surgical decision making.

CD47-SIRPα Signaling Induces Epithelial-Mesenchymal Transition and Cancer Stemness and Links to a Poor Prognosis in Patients with Oral Squamous Cell Carcinoma

Background: Oral squamous cell carcinoma (OSCC), with high mortality rates, is one of the most diagnosed head and neck cancers. Epithelial-to-mesenchymal transition (EMT) and the generation of cancer stem cells (CSCs) are two keys for therapy-resistance, relapse, and distant metastasis. Accumulating evidence indicates that aberrantly expressed cluster of differentiation (CD)47 is associated with cell-death evasion and metastasis; however, the role of CD47 in the generation of CSCs in OSCC is not clear. Methods: We investigated the functional roles of CD47 in OSCC cell lines SAS, TW2.6, HSC-3, and FaDu using the bioinformatics approach, immunoblotting, immunofluorescence staining, and assays for cellular migration, invasion, colony, and orosphere formation, as well as radiosensitivity. Results: We demonstrated increased expression of CD47 in OSCC patients was associated with an estimated poorly survival disadvantage (p = 0.0391) and positively correlated with the expression of pluripotency factors. Silencing CD47 significantly suppressed cell viability and orosphere formation, accompanied by a downregulated expression of CD133, SRY-Box transcription factor 2 (SOX2), octamer-binding transcription factor 4 (OCT4), and c-Myc. In addition, CD47-silenced OSCC cells showed reduced EMT, migration, and clonogenicity reflected by increased E-cadherin and decreased vimentin, Slug, Snail, and N-cadherin expression. Conclusion: Of therapeutic relevance, CD47 knockdown enhanced the anti-OSCC effect of radiotherapy. Collectively, we showed an increased CD47 expression promoted the generation of CSCs and malignant OSCC phenotypes. Silencing CD47, in combination with radiation, could provide an alternative and improved therapeutic efficacy for OSCC patients.

Disruption of mitochondrial homeostasis with artemisinin unravels anti-angiogenesis effects via auto-paracrine mechanisms

Rationale: Tumor angiogenesis promotes tumor development, progression, growth, and metastasis. Metronomic chemotherapy involves the frequent administration of low-dose chemotherapeutic agents to block angiogenic activity and reduce side effects.

Methods: MDA-MB-231 cells were treated with various concentrations of artemisinin (ART) and vinorelbine (NVB) and the cytotoxic effects of ART/NVB were determined using the CCK-8 assay. Mitochondrial reactive oxygen species (ROS) levels, mitochondrial membrane potential (∆Ψm) and mass were assessed using MitoSOX, TMRE and MitoTracker green staining. Western blot analysis was used to quantify the expression of autophagy-related proteins. Herein, by using bioinformatics analysis and experimental verification, we identified CREB as a master in MDA-MB-231 cells.

Results: We found that artemisinin (ART), which exhibits anti-angiogenic and anti-cancer effects via mitochondrial regulation, synergized with vinorelbine (NVB) to inhibit MDA-MB-231 cell proliferation. ART and NVB cooperated to regulate mitochondrial biogenesis. CREB acted as a crucial regulator of PGC1α and VEGF, which played critical roles in NVB-dependent growth factor depletion. Moreover, CREB suppression significantly reversed mitochondrial dysfunction following ART/NVB co-treatment. In addition, combination treatment with ART and NVB significantly suppressed tumor growth in a nude mouse xenograft model, with downregulated CREB and PGC1α expression levels observed in tumor biopsies, in agreement with our in vitro and ex vivo data.

Conclusions: These findings support the hypothesis that ART affects cancer and endothelial cells by targeting the auto-paracrine effects of VEGF to suppress mitochondrial biogenesis, angiogenesis, and migration between cancer cells and endothelial cells.

The Molecular Mechanism of Epithelial-Mesenchymal Transition for Breast Carcinogenesis

The transforming growth factor-β (TGF-β) signaling pathway plays multiple regulatory roles in the tumorigenesis and development of cancer. TGF-β can inhibit the growth and proliferation of epithelial cells and induce apoptosis, thereby playing a role in inhibiting breast cancer. Therefore, the loss of response in epithelial cells that leads to the inhibition of cell proliferation due to TGF-β is a landmark event in tumorigenesis. As tumors progress, TGF-β can promote tumor cell invasion, metastasis, and drug resistance. At present, the above-mentioned role of TGF-β is related to the interaction of multiple signaling pathways in the cell, which can attenuate or abolish the inhibition of proliferation and apoptosis-promoting effects of TGF-β and enhance its promotion of tumor progression. This article focuses on the molecular mechanisms through which TGF-β interacts with multiple intracellular signaling pathways in tumor progression and the effects of these interactions on tumorigenesis.

Role of Cancer Stem Cells in Cholangiocarcinoma and Therapeutic Implications

Cholangiocarcinoma (CCA) is the second most common type of liver cancer, and is highly aggressive with very poor prognosis. CCA is classified into intrahepatic cholangiocarcinoma (iCCA) and extra-hepatic cholangiocarcinoma (eCCA), which is further stratified into perihilar (pCCA) and distal (dCCA). Cancer stem cells (CSCs) are a subpopulation of cancer cells capable of tumor initiation and malignant growth, and are also responsible for chemoresistance. Thus, CSCs play an important role in CCA carcinogenesis. Surface markers such as CD133, CD24, CD44, EpCAM, Sox2, CD49f, and CD117 are important for identifying and isolating CCA CSCs. CSCs are present in the tumor microenvironment (TME), termed ‘CSC niche’, where cellular components and soluble factors interact to promote tumor initiation. Epithelial-to-mesenchymal transition (EMT) is another important mechanism underlying carcinogenesis, involved in the invasiveness, metastasis and chemoresistance of cancer. It has been demonstrated that EMT plays a critical role in generating CSCs. Therapies targeting the surface markers and signaling pathways of CCA CSCs, proteins involved in TME, and immune checkpoint proteins are currently under investigation. Therefore, this review focuses on recent studies on the roles of CSCs in CCA; the possible therapeutic strategies targeting CSCs of CCA are also discussed.

Cancer-Derived VEGF-C Increases Chemokine Production in Lymphatic Endothelial Cells to Promote CXCR2-Dependent Cancer Invasion and MDSC Recruitment

Breast cancer-derived vascular endothelial growth factor-C (VEGF-C) has been shown to enhance lymphangiogenesis in lymph nodes to accelerate cancer metastasis. However, the remodeling of lymph node microenvironments by VEGF-C remains elusive. By in vivo selection, we established a subline (named as “LC”) with strong lymphatic tropism and high VEGF-C expression from the human MDA-MB-231 breast cancer cell line. Co-culture with LC cells or treatment with LC-conditioned medium upregulated the expression of CXC chemokines in lymphatic endothelial cells (LECs), which could be inhibited by pre-incubation with VEGF-C-neutralizing antibodies and VEGFR3 inhibitors. The chemokines produced by LECs enhanced recruitment of myeloid-derived suppressor cells (MDSCs) to tumor-draining and distant lymph nodes in tumor-bearing mice. Treatment with a CXCR2 inhibitor after tumor cell inoculation dramatically decreased the number of MDSCs in lymph nodes, suggesting the importance of the chemokine/CXCR2 signaling axis in MDSC recruitment. In addition, LEC-released chemokines also stimulated the expression of serum amyloid A1 (SAA1) in cancer cells, enhancing their lymphatic invasion by increasing VE-cadherin phosphorylation, junction disruption, and vascular permeability of LECs. Clinical sample validation confirmed that SAA1 expression was associated with increased lymph node metastasis. Collectively, we reveal a novel mechanism by which cancer cell-derived VEGF-C remodels lymphovascular microenvironments by regulating chemokine production in LECs to promote cancer invasion and MDSC recruitment. Our results also suggest that inhibition of CXCR2 is effective in treating lymphatic metastasis.

The Epidemiology of Gastric Cancers in the Era of Helicobacter pylori Eradication: A Nationwide Cancer Registry-Based Study in Taiwan

BACKGROUND

Helicobacter pylori eradication has been shown to decrease gastric adenocarcinoma risk. The epidemiology of gastric lymphoma, which is also associated with H. pylori, and other rare subtypes of gastric cancer is less clear. This study comprehensively evaluated the incidence trend and the survival of gastric cancer in Taiwan by histologic subtype.

METHODS

The incidence trends of gastric cancer in Taiwan from 1996 and 2013 were evaluated using data from the Taiwan Cancer Registry. The life-table method and the Cox proportional hazards analysis were used to evaluate the survival of gastric cancer.

RESULTS

The incidence of all gastric cancers in Taiwan decreased from 15.97 per 100,000 in 1996 to 11.57 per 100,000 in 2013. The most frequent histologic subtype of gastric cancer in Taiwan was adenocarcinoma, followed by lymphoma and sarcoma (mainly gastrointestinal stromal tumor). The best survival was in patients with sarcoma, followed by lymphoma, neuroendocrine tumor, and adenocarcinoma. Generally, women had a better survival than men. The incidence of adenocarcinoma significantly decreased from 13.56 per 100,000 in 1996 to 9.82 per 100,000 in 2013 (P < 0.0001). In contrast, the incidences of mucosa-associated lymphoid tissue lymphoma and diffuse large B-cell lymphoma did not decrease.

CONCLUSIONS

The incidence of adenocarcinoma and lymphoma, both of which are associated with H. pylori, showed diverging trends. The survival of gastric cancer differed by histologic subtype and sex.

IMPACT

The disparity in the incidence trends between gastric lymphoma and adenocarcinoma, both associated with H. pylori, warranted the need to search for additional risk factors of gastric lymphoma.

Co-Delivery of Natural Compounds with a Dual-Targeted Nanoparticle Delivery System for Improving Synergistic Therapy in an Orthotopic Tumor Model

Various natural compounds including epigallocatechin gallate (EGCG) and curcumin (CU) have potential in developing anticancer therapy. However, their clinical use is commonly limited by instability and low tissue distribution. EGCG and CU combined treatment can improve the efficacy with synergistic effects. To improve the synergistic effect and overcome the limitations of low tissue distribution, we applied a dual cancer-targeted nanoparticle system to co-deliver EGCG and CU. Nanoparticles were composed of hyaluronic acid, fucoidan, and poly(ethylene glycol)-gelatin to encapsulate EGCG and CU. Furthermore, a dual targeting system was established with hyaluronic acid and fucoidan, which were used as agents for targeting CD44 on prostate cancer cells and P-selectin in tumor vasculature, respectively. Their effect and efficacy were investigated in prostate cancer cells and a orthotopic prostate tumor model. The EGCG/CU-loaded nanoparticles bound to prostate cancer cells, which were uptaken more into cells, leading to a better anticancer efficiency compared to the EGCG/CU combination solution. In addition, the releases of EGCG and CU were regulated by their pH value that avoided the premature release. In mice, treatment of the cancer-targeted EGCG/CU-loaded nanoparticles significantly attenuated the orthotopic tumor growth without inducing organ injuries. Overall, the dual-targeted nanoparticle system for the co-delivery of EGCG and CU greatly improved its synergistic effect in cancer therapy, indicating its great potential in developing treatments for prostate cancer therapy.

Abstract 1711: Kynurenine 3-monooxygenase (KMO) acts as a novel oncoprotein in triple negative breast cancer

Purpose: Tryptophan-kynurenine pathway involves in inflammation, immune response and tumorigenesis, in which kynurenine 3-monooxygenase (KMO), an outer mitochondrial membrane protein, mediating kynurenine metabolism. Previous studies indicated KMO showed increased activity in breast cancer. Triple-negative breast cancer (TNBC) tumors exhibited elevated levels of tryptophan metabolites compared to estrogen receptor positive breast cancers. We aimed to study the role of KMO in human TNBC.

Experimental design: The gene alterations and transcripts of enzymes in kynurenine metabolism were analyzed from The Cancer Genome Atlas (TCGA) database. Immunohistochemical staining for KMO was performed and a H-score was assigned to quantify protein expression. Epithelial-mesenchymal transition (EMT) phenotypes were examined by transwell assay and EMT markers expressions. Stemness properties were assessed by mammosphere assay and pluripotent genes expressions. The molecular events were analyzed by Western blot, quantitative real-time PCR and luciferase reporter assay. Tumor growth and metastasis were conducted in nude mice and NOD-SCID mice by subcutaneous and tail vein injection respectively.

Results: TCGA databases showed KMO but not KYNU and KAT2 was amplified in breast cancer. Both the data from TCGA and our in-house IHC-based tissue-microarray exhibited increased KMO expression in TNBC compared to normal tissue. In vitro, overexpression of KMO in TNBC cells resulted in increased cell growth and colony formation. The abilities migration and invasion as well as EMT markers expressions of TNBC cells were elevated by KMO overexpression. In addition, KMO increased mammosphere formation, pluripotent genes expressions and promoter activities. However, inhibition of KMO enzymatic activity by KMO inhibitors did not affect cancer progression or mitochondrial respiration of TNBC cells. KMO upregulated β-catenin, the upstream regulator of pluripotent genes, CD44 and Nanog expressions. Mechanistically, data showed KMO expressed in both cytosol and nuclear fractions and was associated with β-catenin. KMO enhanced pluripotent genes expressions through β-catenin upregulation. Importantly, KMO knockdown suppressed tumor growth and expressions of β-catenin, CD44 and Nanog in TNBC tumors. Moreover, KMO knockout significantly decreased lung metastasis in vivo.

Conclusion: Our data indicated KMO can play an oncogenic role in TNBC, acting as a novel regulator of pluripotent genes via β-catenin and promoted TNBC progression.

Citation Format: Chun-Yu Liu, Tzu-Ting Huang, Ji-Lin Chen, Chia-Han Lee, Wan-Lun Wang, Ka-Yi Lau, Chun-Teng Huang, Pei-Yi Chu, Hsin-Chen Lee, Ling-Ming Tseng. Kynurenine 3-monooxygenase (KMO) acts as a novel oncoprotein in triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1711.

Abstract 4715: Combination of Tacedinaline and EHMT2 inhibition increases breast cancer cell death involving BIRC5 repression and GADD45A induction

The genomes of cancer cells are different from those of normal cells. These differences include genetic and epigenetic alterations, such as variations of DNA methylation and histone modifications, which cause differential gene expression, increased cell growth/migration capacity, and may induce resistance to anticancer therapy. Thus, epigenetic modulation may have a chance to correct abovementioned cancer cell’s aberrations in gene expression and cell behaviors, resulting in eradication of primary and/or suppression of refractory cancers.

Tacedinaline (CI-994) and UNC0638 are specific inhibitors of class I histone deacetylase (HDAC) and histone methyltransferase EHMT2 (G9a), which cause an increase of histone acetylation and a decrease of histone H3 dimethylation at lysine 9, respectively. Here we examined the therapeutic effect of CI-994 and UNC0638 combination on the triple-negative (MDA-MB-231) and estrogen receptor-positive (MCF-7) breast cancer cell lines.

The results showed that the combination of CI-994 and UNC0638 was able to induce more severe cell death than either agent alone. Although the sub-G1 fraction and Annexin V-positive cells were increased, CI-994 and UNC0638 did not significantly induce the activities of caspases 3, 8 and 9, suggesting the involvement of non-canonical and caspase-independent cell death mechanism. Instead, CI-994 suppressed the expression of BIRC5 (Survivin, a member of the inhibitor of apoptosis protein) and, in combination with UNC0638, induced the expression of GADD45A (involved in stress-induced apoptosis).

Mechanistically, combination of CI-994 and UNC0638 resulted in the changes of epigenetic marks, such as acetylation and methylation of histone H3, at the loci of BIRC5 and GADD45A, which were correlated with their altered gene expressions. Genetic knockdown of BIRC5 expression in MCF-7 decreased cell viability, supporting the pro-survival role of BIRC5 in breast cancer cells.

Importantly, the targets of CI-994 (HDAC1, HDAC2) and UNC0638 (EHMT2), as well as BIRC5 were overexpressed in breast cancer specimens, especially those of triple-negative breast cancer (TNBC), based on the analyses of The Cancer Genome Atlas dataset. Meanwhile, the expression of GADD45A was downregulated. BIRC5 upregulation and GADD45A downregulation in breast cancer were associated with patient’s overall survival.

These results suggest that Tacedinaline and UNC0638, or targeting the class I HDAC and EHMT2, may be a potential strategy to treat breast cancer including TNBC.

Citation Format: Pei-Yi Chu, Ji-Ching Lai, Ming-Feng Hou, Chang-Shen Lin. Combination of Tacedinaline and EHMT2 inhibition increases breast cancer cell death involving BIRC5 repression and GADD45A induction [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4715.

Overexpression of LGR-5 as a Predictor of Poor Outcome in Patients with Hepatocellular Carcinoma

Hepatocarcinogenesis and distant metastasis pose major challenges for physicians. They are regulated by several genes, such as AKT, JUK, Wnt, and P53, and their expression activates several important processes such as cell proliferation, migration, motility, and interaction in the microenvironment. The leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR-5) is a novel biomarker, particularly in stem cells, and is involved in embryogenesis, tumor development, and tumor cell signal transduction. Here, we investigated LGR-5 expression using immunohistochemistry and analyzed the correlation between clinical features and prognosis in patients with hepatocellular carcinoma (HCC). We found that LGR-5 expression was higher in tumor tissues than in normal liver tissues, and that high LGR-5 expression possibly favored poor outcomes in HCC, especially in well/moderate differentiation grade, hepatitis C virus (HCV)-negative, and hepatitis B virus (HBV)-positive groups. Thus, the LGR-5 marker is suggested to be a routine biomarker for poor prognosis, thereby providing a platform for anti-LGR-5-targeted therapy in the future.

Protein Arginine Methyltransferase 3 Enhances Chemoresistance in Pancreatic Cancer by Methylating hnRNPA1 to Increase ABCG2 Expression

Pancreatic cancer is poorly responsive to chemotherapy due to intrinsic or acquired resistance. Our previous study showed that epigenetic modifying enzymes including protein arginine methyltransferase 3 (PRMT3) are dysregulated in gemcitabine (GEM)-resistant pancreatic cancer cells. Here, we attempt to elucidate the role of PRMT3 in chemoresistance. Overexpression of PRMT3 led to increased resistance to GEM in pancreatic cancer cells, whereas reduction of PRMT3 restored GEM sensitivity in resistant cells. We identified a novel PRMT3 target, ATP-binding cassette subfamily G member 2 (ABCG2), which is known to play a critical role in drug resistance. PRMT3 overexpression upregulated ABCG2 expression by increasing its mRNA stability. Mass spectrometric analysis identified hnRNPA1 as a PRMT3 interacting protein, and methylation of hnRNPA1 at R31 by PRMT3 in vivo and in vitro. The expression of methylation-deficient hnRNPA1-R31K mutant reduced the RNA binding activity of hnRNPA1 and the expression of ABCG2 mRNA. Taken together, this provides the first evidence that PRMT3 methylates the RNA recognition motif (RRM) of hnRNPA1 and promotes the binding between hnRNPA1 and ABCG2 to enhance drug resistance. Inhibition of PRMT3 could be a novel strategy for the treatment of GEM-resistant pancreatic cancer.

The incidence and survival of pancreatic cancer by histology, including rare subtypes: a nation-wide cancer registry-based study from Taiwan

Studies have indicated a significant rise in the incidence of pancreatic adenocarcinoma. However, the epidemiology of other rare histologic subtypes of pancreatic cancer is not well understood. This study analyzed the incidence and survival of pancreatic cancer in Taiwan by histologic subtype, sex, age group, and year of diagnosis. The incidence trends of pancreatic cancer in Taiwan from 2002 to 2013 were calculated using data from the Taiwan Cancer Registry. The survival of pancreatic cancer patients was assessed using the life-table method and Cox proportional hazards analysis. The incidence of pancreatic cancer increased from 4.62 per 100,000 in 2002 to 6.04 per 100,000 in 2013 in Taiwan. The most common histologic subtype of pancreatic cancer was adenocarcinoma followed by carcinoma and neuroendocrine tumors (NETs). Adenocarcinoma and NETs showed a rapid increase in incidence, while the incidences of other subtypes did not change significantly. Patients with adenocarcinoma showed a poor survival with a 5-year survival of 5.2%. Patients with endocrinomas, NETs, and lymphoma displayed a better survival than those with adenocarcinoma, with a 5-year survival ranging from 41.8% to 59.1%. The survival of adenocarcinoma, lymphoma, and NETs improved after the introduction of novel therapies. Understanding the risk factors and identifying the biomarkers for the early diagnosis of pancreatic cancer are important to prevent the development and improve the survival of pancreatic cancer.

Overexpression of epithelial cell adhesion molecule as a predictor of poor outcome in patients with hepatocellular carcinoma

Cancer growth, metastasis and development are regulated by a number of genes, whose expression mediates important processes, including cellular plasticity, motility and internal interactions in the tumor microenvironment. The epithelial cell adhesion molecule (EpCAM) serves an important role in cell-cell migration and tumorigenicity, particularly metastasis. The aim of the present study was to measure EpCAM expression using immunohistochemistry and to investigate the association between clinicopathological features and prognosis in hepatocellular carcinoma (HCC). The results revealed that EpCAM expression may be a biomarker for poor prognosis in patients with HCC and may therefore be used to predict clinical outcome. The present study suggests that EpCAM expression in HCC can be considered as a routine biomarker for unfavorable prognosis and may provide a basis for the future development of anti-EpCAM-targeted therapy.

Molecular Targets in Hepatocarcinogenesis and Implications for Therapy

Hepatocarcinogenesis comprises of multiple, complex steps that occur after liver injury and usually involve several pathways, including telomere dysfunction, cell cycle, WNT/β-catenin signaling, oxidative stress and mitochondria dysfunction, autophagy, apoptosis, and AKT/mTOR signaling. Following liver injury, gene mutations, accumulation of oxidative stress, and local inflammation lead to cell proliferation, differentiation, apoptosis, and necrosis. The persistence of this vicious cycle in turn leads to further gene mutation and dysregulation of pro- and anti-inflammatory cytokines, such as interleukin (IL)-1β, IL-6, IL-10, IL-12, IL-13, IL-18, and transforming growth factor (TGF)-β, resulting in immune escape by means of the NF-κB and inflammasome signaling pathways. In this review, we summarize studies focusing on the roles of hepatocarcinogenesis and the immune system in liver cancer. In addition, we furnish an overview of recent basic and clinical studies to provide a strong foundation to develop novel anti-carcinogenesis targets for further treatment interventions.

Abstract 4372: SET/PP2A/SHP-1/Lyn oncogenic signaling contributes to tumor aggressiveness in diffuse large B cell lymphoma

Purpose:

Diffuse large B-cell lymphoma (DLBCL) is aggressive non-Hodgkin lymphoma. It is a heterogeneous disease and is classified as germinal center B-cell like (GCB) and activated B-cell like (ABC) subtypes according to gene-expression profiling. The oncogenic pathways in DLBCL are potential targets for new therapies. In present study, the role and regulation of SET/PP2A/SHP-1/Lyn axis in DLBCL were investigated.

Experimental design: U2932, OCL-Ly3, OCI-Ly7, SU-DHL-6 and DB DLBCL cell lines were used for this study. TD-19, a novel SET/PP2A protein-protein interaction inhibitor, was used to address the molecular events of SET signaling. Cell viability was measured by MTT assay. The apoptotic cells were examined by PI/Annexin V staining and Western blotting. SHP-1, Lyn and pLyn were analyzed by immunohistochemistry on lymphoma tissue microarrays from DLBCL patients.

Results:

We first examined the effects of two different SET inhibitors, TD-19 that is a SET/PP2A protein protein interaction inhibitor, and FTY720 which is a sphingosine analogue that targets SET, on DLBCL cells. TD-19 and FTY720 significantly decreased cell viability and induced apoptosis. SET inhibition activated PP2A and SHP-1 by reducing pPP2AY307 and pSHP-1S591 and inactivated Lyn by decreasing pLynY396. Overexpression of SET rescued these molecular events, and promoted cell growth and migration. Interestingly, we observed the level of SET was declined by TD-19 and TFY720 treatment. We hypothesized Lyn might up-regulate SET expression. Overexpression of Lyn increased SET level, and was accompanied with phosphorylation of PP2A (pPP2AY307) and SHP-1 (pSHP-1S591). Lyn elevated cell growth and migration and suppressed PP2A and SHP-1 activities. Moreover, exogenous SET restored the FTY720- and TD-19-suppressed pSHP-1 and pLyn. Immunohistochemically, high SHP-1 level was linked to low pLyn level of patient with DLBCL and vice versa.

Conclusion: This study established the existence of positive feedback of SET/PP2A/SHP-1/Lyn axis in DLBCL cells, and targeting SET could disrupt this regulation.

Citation Format: Ji-Lin Chen, Wen-Chun Tsai, Tien-Yun Lan, Chun-Teng Huang, Pei-Yi Chu, Chia-Han Lee, Ka-Yi Lau, Wan-Lun Wang, Kuen-Feng Chen, Chung-Wai Shiau, Chun-Yu Liu. SET/PP2A/SHP-1/Lyn oncogenic signaling contributes to tumor aggressiveness in diffuse large B cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4372.

Abstract 762: Disrupting the glucose-influx induced β-catenin activation for the treatment of hepatocellular carcinoma

Background: Reprogramming of glucose metabolism is a critical hallmark in hepatocellular carcinoma (HCC), and alteration of WNT/β-catenin signaling is one of the most common molecular alterations observed in patients with HCC. Interestingly, some studies reported that high glucose exposure leaded to activation of WNT/β-catenin signaling. But, for HCC, whether the accelerated glucose metabolism affects β-catenin, and whether this singling pathway reserves potential for the development of novel anti-cancer treatment have not yet been explored.

Method:

HCC cells were exposed to different glucose conditions and various glucose transporter inhibitors, including Phloretin, WZB117, Canagliflozin, Dapagliflozin and Empagliflozin. Cells were examined for cell viability and molecular signaling after treatments. Huh7 xenografted tumor model was used for in vivo testing. Clinical HCC tumor tissues were examined by immunohistochemical stain.

Result:

HCC cells exposed to high glucose environment showed higher proliferation rate and upregulated β-catenin as comparing to those cultured in lower glucose-median. Notably, a similar association was observed in the clinical samples; HCC patients with higher glycemic level had stronger expressions of β-catenin in their tumors (p=0.034). Above data suggested that high glucose condition induced activation of β-catenin. Next, we asked whether blocking glucose influx attenuates this glucose-influx-mediated β-catenin activation and inhibits HCC cell growth. By treating HCC cells with various glucose transporter inhibitors, we found that canagliflozin, Phloretin and WZB117 attenuated

glucose influx of HCC cells, but only canagliflozin showed potent growth inhibition against HCC. Furthermore, treatment of canagliflozin leaded to a dose-dependent downregulation of β-catenin in HCC cells. Using cycloheximide and MG-132, we proved that canagliflozin treatment promoted the proteasome-mediated degradation of β-catenin protein. Since the phosphorylation of β-catenin is the initial step for its degradation, we examined the expression of p-β-catenin and found that canagliflozin treatment increased the expressions of p-Ser33/Ser37/Thr41-β-catenin and p-Ser45-β-catenin. Furthermore, the activity of protein phosphatase 2A (PP2A) was decreased in canagliflozin-treated HCC cells. The roles of glucose-influx and PP2A/p-β-catenin mediating the anti-HCC effects of canagliflozin were validated. Moreover, in vivo tumor growth inhibition of canagliflozin treatment was shown.

Conclusion:

Our results showed that high glucose upregulated beta-catenin signaling in HCC. Canagliflozin, by direct promoting the degradation of β-catenin protein and attenuating glucose-influx, inhibits the glucose-influx-mediated β-catenin activation and produces anti-HCC effects in vitro and in vivo.

Citation Format: Man-Hsin Hung, Li-Ju Chen, Pei-Yi Chu, Yao-Li Chen, Ming-Hsien Tsai, Feng-Shu Hsieh, Kuen-Feng Chen. Disrupting the glucose-influx induced β-catenin activation for the treatment of hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 762.

Abstract 4612: SET overexpression is associated with recurrence-free survival in patients with primary breast cancer receiving adjuvant tamoxifen treatment

Background:

Estrogen receptor (ER) positive breast cancer accounts for 70% of breast cancer. Tamoxifen, a selective ER modulator, remains an important hormone therapeutic agent for patients with ER positive breast cancer. A number of patients receiving adjuvant tamoxifen still experience recurrence in the long term. In current study we explored the clinical significance of four biomarkers including SET, CIP2A, PP2A and Akt in ER positive breast cancer patients receiving adjuvant tamoxifen.

Methods:

Specimens were from ER positive breast cancer patients treated with adjuvant tamoxifen for a median of duration of 54.8 months with documented outcomes. The median follow-up was 106 months. Immunohistochemical staining for SET, CIP2A, p-PP2A (Tyr 307), p-Akt were performed and a H-score was assigned to quantify protein expression. In silico analysis of gene expression was evaluated from the public database KM plotter (available at: http://kmplot.com/analysis/). Human ER positive breast cancer cell line MCF7 cells were used for in vitro studies. MTT assay, flow cytometry and Western blot were used to assess the cells properties. Estrogen response element (ERE)-dependent luciferase activity was assessed by co-transfection of SET-expressing or control plasmids and 3⊆ERE bearing reporter plasmids into MCF7 cells and stimulated with estrogen.

Results:

In 218 primary ER positive breast cancer patients treated with adjuvant tamoxifen, 17 (7.8%) suffered from recurrence or metastasis. Higher expressions of SET and CIP2A by IHC analysis were associated with poor recurrence-free survival (RFS). Multivariate analysis revealed SET was independently correlated with worse RFS (Hazard ratio=3.72, 95% confidence interval 1.26-10.94, p=0.017). In silico, KM-plotter analysis revealed higher gene (mRNA) expressions of SET, PPP2CA and

Akt1 significantly correlated with worse RFS in breast cancer patients receiving adjuvant tamoxifen therapy. Because SET appeared to be the most prognostic for RFS among the four markers, we next explored the biological role in vitro. Tamoxifen exerted anti-proliferation and apoptotic effects in a dose-dependent manner of MCF7 cells. SET overexpression reduced tamoxifen-induced anti-proliferation in MCF-7 cells, in association with upregulated p-ER, suggesting that SET may affect ER pathway via the serine/threonine kinase PP2A. SET drove luciferase activity in an ERE-dependent manner, and also enhanced estrogen-promoted luciferase activity.

Conclusions:

Protein SET is a prognostic biomarker in ER positive breast cancer patients treated with tamoxifen and may contribute to tamoxifen resistance by modulating ER signaling pathway.

Citation Format: Yu-Hsiang Huang, Pei-Yi Chu, Ji-Lin Chen, Chun-Teng Huang, Chia-Han Lee, Ka-Yi Lau, Wan-Lun Wang, Yu-Ling Wang, Pei-Ju Lien, Ling-Ming Tseng, Chun-Yu Liu. SET overexpression is associated with recurrence-free survival in patients with primary breast cancer receiving adjuvant tamoxifen treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4612.

IFI44L is a novel tumor suppressor in human hepatocellular carcinoma affecting cancer stemness, metastasis, and drug resistance via regulating met/Src signaling pathway

BACKGROUND

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related death worldwide. The disease recurrent rate is relatively high resulted in poor 5-year survival in advanced HCC. Cancer stem cells (CSCs) have been considered to be one of the main mechanisms for chemoresistance, metastasis, and recurrent disease. Interferon-induced protein 44-like (IFI44L) gene is a type I interferon-stimulated gene (ISG) and belongs to the IFI44 family. Previous reports indicated antiviral activity against HCV in IFI44L, however, its precise role and function in HCC has not been unveiled.

METHODS

To explore the characteristics of hepatic CSCs, we successfully enriched hepatic cancer stem-like cells from three established liver cancer cell lines (Hep3B, HepG2, and PLC lines). Parental Hep3B and HepG2 cells and their sphere cells were treated with doxorubicin for 48 h and cell viability was measured by MTT assay. HCC tissue blocks from 217 patients were sampled for tissue microarray (TMA). Follow-up information and histopathological and clinical data including age, gender, tumor grade, advanced stages, HBV, HCV, tumor number, tumor size, relapse-free survival, and overall survival were obtained from the cancer registry and medical charts. The liver TMA was evaluated for IFI44L expression using immunohistochemical staining and scores.

RESULTS

These hepatic cancer stem-like cells possess important cancer stemness characteristics including sphere-forming abilities, expressing important HCC cancer stem cell markers, and more chemoresistant. Interestingly, we found that overexpression of IFI44L decreased chemoresistance towards doxorubicin and knockdown of IFI44L restored chemoresistance as well as promoted sphere formation. Furthermore, we found that depletion of IFI44L enhanced migration, invasion, and pulmonary metastasis through activating Met/Src signaling pathway. Clinically, the expression level of IFI44L significantly reduced in HCC tumor tissues. Low expression of IFI44L levels also correlated with larger tumor size, disease relapse, advanced stages, and poor clinical survival in HCC patients.

CONCLUSION

Taken together, we first demonstrated that IFI44L is a novel tumor suppressor to affect cancer stemness, metastasis, and drug resistance via regulating Met/Src signaling pathway in HCC and can be serve as an important prognostic marker.

Molecular Regulation of Bone Metastasis Pathogenesis

Distant metastases are the major cause of mortality in cancer patients. Bone metastases may cause bone fractures, local pain, hypercalcemia, bone marrow aplasia, and spinal cord compression. Therefore, the management of bone metastases is important in cancer treatment. Normal bone remodeling is regulated by osteoprotegerin ligand (OPGL), receptor activator of NF-κB ligand (RANKL), parathyroid hormone-related protein (PTHrP), and other cytokines. In the tumor microenvironment, tumor cells induce a vicious cycle that promotes osteoblastic and osteolytic lesions. Studies support the idea that distant metastases may occur due to the immunosuppressive function of myeloid-derived suppressor cells (MDSCs). These cells inhibit T cells and natural killer (NK) cells and differentiate into tumor-associating macrophages (TAMs), monocytes, and dendritic cells (DCs). In this review, we summarize studies focusing on the role of MDSCs in bone metastasis and provide a strong foundation for developing anticancer immune treatments and anticancer therapies, in general.