Search

Methionine addiction is a fundamental and general hallmark of cancer. Gene expression analysis showed that methionine restriction (MR) of methionine-addicted cancer cells increases TNF-related apoptosis-induced ligand receptor-2 (TRAIL-R2) expression. Here, we determined the effects of MR on TRAIL-R2 targeted therapy in pancreatic cancer by the TRAIL-R2 agonist tigatuzumab. Human pancreatic cancer cell lines were cultured in control or methionine-free medium. The effects of MR on TRAIL-R2 expression and sensitivity to tigatuzumab were evaluated in vitro. An orthotopic pancreatic cancer mouse model was established to evaluate the efficacy of MR using oral recombinant methioninase (o-rMETase), and the efficacy of tigatuzumab and their combination. MR enabled tigatuzumab-induced apoptosis, by increasing TRAIL-R2 expression in pancreatic cancer cells in vitro. The protein expression level of the melanoma-associated antigen MAGED2, which reduces TRAIL-R2 expression, was decreased by MR. In the orthotopic pancreatic cancer mouse model, o-rMETase increased TRAIL-R2 expression level in the tumors and enabled the antitumor efficacy of tigatuzumab. MR, effected by o-rMETase, enabled the efficacy of the TRAIL-R2 agonist tigatuzumab by increasing TRAIL-R2 expression in pancreatic cancer. Our results suggest that o-rMETase has clinical potential for treating pancreatic cancer., (Published by Elsevier B.V.)

Sarcoma is a rare and recalcitrant malignancy. Although immune and novel targeted therapies have been tested on many cancer types, few sarcoma patients have had durable responses with such therapy. Doxorubicin and cisplatinum are still first-line chemotherapy after four decades. Our laboratory has established the patient-derived orthotopic xenograft (PDOX) model using surgical orthotopic implantation (SOI). Many promising results have been obtained using the sarcoma PDOX model for identifying effective approved drugs and experimental therapeutics, as well as combinations of them for individual patients. In this review, we present our laboratory's experience with PDOX models of sarcoma, and the ability of the PDOX models to identify effective approved agents, as well as experimental therapeutics., (Published by Elsevier B.V.)

The pancreatic cancer microenvironment is crucial in cancer development, progression and drug resistance. Cancer-stromal interactions have been recognized as important targets for cancer therapy. However, identifying relevant and druggable cancer-stromal interactions is challenging due to the lack of quantitative methods to analyze the whole cancer-stromal interactome. Here we studied 14 resected pancreatic cancer specimens (8 pancreatic adenocarcinoma (PDAC) patients as a cancer group and 6 intraductal papillary-mucinous adenoma (IPMA) patients as a control). Shotgun proteomics of the stromal lesion dissected with laser captured microdissection (LCM) was performed, and identified 102 differentially expressed proteins in pancreatic cancer stroma. Next, we obtained gene expression data in human pancreatic cancer and normal pancreatic tissue from The Cancer Genome Atlas database (n = 169) and The Genotype-Tissue Expression database (n = 197), and identified 1435 genes, which were differentially expressed in pancreatic cancer cells. To identify relevant and druggable cancer-stromal-interaction targets, we applied these datasets to our in-house ligand-receptor database. Finally, we identified 9 key genes and 8 key cancer-stromal-interaction targets for PDAC patients. Furthermore, we examined FN1 and ITGA3 protein expression in pancreatic cancer tissues using tissue microarrays (TMAs) of 271 PDAC cases, and demonstrated that FN1-ITGA3 had unfavorable prognostic impact for PDAC patients., (Published by Elsevier B.V.)

Pancreatic cancer is one of the leading causes of cancer death, mainly due to the absence of early diagnostic tool and effective therapeutic agents. To identify an effective therapeutic agent for pancreatic ductal adenocarcinoma cells (PDAC), we used 10 Gene Expression Omnibus (GEO) data sets and L1000CDS 2 pharmacogenetic search tool and obtained chemical "perturvants" that were predicted to reverse the abnormal gene expression changes in PDAC. Among 20 initial candidates, we measured IC 50 for six compounds and identified BX-795, PDK1/TBK1 inhibitor, as a therapeutic candidate. We found that BX-795 inhibits primary PDAC cell proliferation more effectively than normal cells. Following molecular analysis revealed that BX-795 down-regulates mTOR-GSK3β pathway and trigger apoptosis. Moreover, we found that BX-795 suppresses primary PDAC cell migration via downregulation of Snail and Slug. Finally, efficacy test in patient-derived xenograft model of PDAC showed BX-795 can inhibit in vivo tumor growth as efficient as gemcitabine and a combination with trametinib further suppresses tumor growth. Collectively, these results demonstrate the BX-795 as an effective therapeutic candidate for PDAC treatment., (Published by Elsevier B.V.)

Olaratumab (OLA), a monoclonal antibody against platelet-derived growth factor receptor alpha (PDGFRα), has recently been used against soft-tissue sarcoma (STS) combined with doxorubicin (DOX), with limited efficacy. The goal of the present study was to determine the efficacy of OLA in combination with DOX and ifosfamide (IFO) on STS. Undifferentiated soft-tissue sarcoma (USTS) from a striated muscle of a patient was grown orthotopically in the right biceps femoris muscle of nude mice to establish USTS patient-derived orthotopic xenograft (PDOX) model. USTS PDOX tumors were treated with OLA alone, DOX alone, DOX combined with IFO, OLA combined with DOX or IFO, and OLA combined with DOX and IFO. Tumor size and body weight were measured during the 14 days of treatment. Tumor growth was arrested by OLA combined with DOX and IFO. Tumors treated with OLA combined with DOX and IFO had the most necrosis. The present study demonstrates the power of the PDOX model to identify the novel effective treatment strategy of the combination of OLA, DOX and IFO for soft-tissue sarcomas., (Published by Elsevier B.V.)

Recombinant methioninase (rMETase) was previously administered as an injectable drug to target methionine dependence of cancer. Recently, we observed that rMETase could be administered orally (o-rMETase) in a patient-derived orthotopic xenograft (PDOX) mouse model of melanoma. Here, we determined the efficacy of o-rMETase on a pancreatic cancer PDOX model. Forty pancreatic cancer PDOX mouse models were randomized into four groups of 10 mice each. o-rMETase was significantly more effective than i.p.-rMETase, but the combination of both was significantly more effective than either alone. Acquired gemcitabine resistance is a major factor in the recalcitrance of pancreatic cancer. We tested a human pancreatic cancer cell line, which has acquired >100-fold GEM-resistance (PK-9R) than its parental cell line PK-9. In contrast to GEM, both cell lines were very sensitive to rMETase. In orthotopic nude mouse models of PK-9 and PK-9R, GEM inhibited tumor growth in PK-9 but not PK-9R. In contrast, o-rMETase could inhibit both tumors. The combination of GEM + o-rMETase could regress the PK-9 tumor and inhibit PK-9R tumor growth. The present study shows that o-rMETase is effective and overcomes acquired GEM resistance in pancreatic cancer and demonstrates the clinical potential of this strategy., (Published by Elsevier B.V.)

Despite the improved 5-year survival rate of breast cancer, triple-negative breast cancer (TNBC) remains a challenge due to lack of effective targeted therapy and higher recurrence and metastasis than other subtypes. To identify novel druggable targets and to understand its unique biology, we tried to implement 24 patient-derived xenografts (PDXs) of TNBC. The overall success rate of PDX implantation was 45%, much higher than estrogen receptor (ER)-positive cases. Immunohistochemical analysis revealed conserved ER/PR/Her2 negativity (with two exceptions) between the original and PDX tumors. Genomic analysis of 10 primary tumor-PDX pairs with Ion AmpliSeq CCP revealed high degree of variant conservation (85.0%-96.9%) between primary and PDXs. Further analysis showed 44 rare variants with a predicted high impact in 36 genes including Trp53, Pten, Notch1, and Col1a1. Among them, we confirmed frequent Notch1 variant. Furthermore, RNA-seq analysis of 24 PDXs revealed 594 gene fusions, of which 163 were in-frame, including AZGP1-GJC3 and NF1-AARSD1. Finally, western blot analysis of oncogenic signaling proteins supporting molecular diversity of TNBC PDXs. Overall, our report provides a molecular basis for the usefulness of the TNBC PDX model in preclinical study., (Published by Elsevier B.V.)

We have previously established a patient-derived orthotopic xenograft (PDOX) model of undifferentiated spindle cell sarcoma (USCS). Recombinant methioninase (rMETase) has previously demonstrated efficacy in PDOX mouse models of human cancers. In the present study, we determined if rMETase in combination with doxorubicin (DOX) can overcome first-line DOX resistance in a PDOX models of USCS. The USCS PDOX mouse models were randomized into the following groups when tumor volume reached 100 mm 3 : G1, control without treatment; G2, doxorubicin (DOX) (3 mg/kg, intraperitoneal [i.p.] injection, weekly, for 2 weeks); G3, rMETase (100 units/mouse, i.p., daily, for 2 weeks); G4, DOX (3 mg/kg, i.p., weekly, for 2 weeks) combined with rMETase (100 units/mouse, i.p., daily, for 2 weeks). Tumor size and body weight were measured twice a week. On day 14 after initiation, the USCS PDOX tumor sizes were (G1): 360 ± 85 mm 3 ; DOX (G2): 355 ± 111 mm 3 , p = .927; rMETase (G3): 182 ± 57 mm 3 , p = .0003; DOX + rMETase (G4): 134 ± 29 mm 3 , p = .00001. These results indicate that rMETase can overcome USCS resistance to DOX, which is first line therapy for this disease. The body weight of treated mice was not significantly different in any group. The present results demonstrate the power of the PDOX model to identify effective therapy for recalcitrant cancer and the potential of rMETase to overcome DOX resistance., (Published by Elsevier B.V.)

Liver cancer is one of the common malignancies in many countries and an increasing cause of cancer death. Despite of that, there are few therapeutic options available with inconsistent outcome, raising a need for developing alternative therapeutic options. Through a drug repositioning screening, we identified and investigated the action mechanism of the Riluzole, an amyotrophic lateral sclerosis (ALS) drug, on hepatocellular carcinoma (HCC) therapy. Treatment of the Riluzole leads to a suppression of cell proliferation in liver primary cancer cells and cancer cell lines. In addition, Riluzole induced caspase-dependent apoptosis and G2/M cell cycle arrest in SNU449 and Huh7 cell lines. In a line with the known function of glutamate release inhibitor, we found Riluzole-treated cells have increased the level of inner cellular glutamate that in turn decrease the glutathione (GSH) level and finally augment the reactive oxygen species (ROS) production. We confirm this finding in vivo by showing the Riluzole-induced GSH and ROS changes in a Huh7 xenograft cancer model. Altogether, these data suggest the anti-cancer effect of Riluzole on hepatocellular carcinoma and the suppression of glutamate signaling might be a new target pathway for HCC therapy., (Published by Elsevier Ireland Ltd.)

Tumor-initiating cells are important for the formation and maintenance of tumor bulks in various tumors. To identify surface markers of liver tumor-initiating cells, we performed primary tumorsphere culture and analyzed the expression of cluster of differentiation (CD) antigen genes using NanoString. Interestingly, we found significant upregulation of the complement proteins (p = 1.60 × 10(-18)), including C7 and CFH. Further studies revealed that C7 and CFH are required to maintain stemness in liver cancer cells. Knockdown of C7 and CFH expression abrogated tumorsphere formation and induced differentiation, whereas overexpression stimulated stemness factor expression as well as in vivo cell growth. Mechanistically, by studying C7 and CFH-dependent LSF-1 expression and its direct role on stemness factor transcription, we found that LSF-1 is involved in this regulation. Taken together, our data demonstrate the unprecedented role of complement proteins on the maintenance of stemness in liver tumor-initiating cells., (Published by Elsevier Ireland Ltd.)

The histone demethylase KDM1A specifically demethylates lysine residues and its deregulation has been implicated in the initiation and progression of various cancers. However, KDM1A's molecular role and its pathological consequences, and prognostic significance in oral cancer remain less understood. In the present study, we sought to investigate the expression of KDM1A and its downstream role in oral cancer pathogenesis. By comparing mRNA expression profiles, we identified an elevated KDM1A expression in oral tumors when compared to normal oral tissues. In silico pathway prediction identified the association between KDM1A and E2F1 signaling in oral cancer. Pathway scanning, functional annotation analysis and In vitro assays showed the KDM1A's involvement in oral cancer cell proliferation and the cell cycle. Moreover, real time PCR and luciferase assays confirmed KDM1A's role in regulation of E2F1 signaling activity in oral cancer. Elevated KDM1A expression is associated with poor clinical outcome in oral cancer. Our data indicate that deregulated KDM1A expression is positively associated with proliferative phenotype of oral cancer and confers poor clinical outcome. These cumulative data suggest that KDM1A might be a potential diagnostic and therapeutic target for oral cancer., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), found in cooked meat, is a known food carcinogen that causes several types of cancer, including breast cancer, as PhIP metabolites produce DNA adduct and DNA strand breaks. Curcumin, obtained from the rhizome of Curcuma longa, has potent anticancer activity. To date, no study has examined the interaction of PhIP with curcumin in breast epithelial cells. The present study demonstrates the mechanisms by which curcumin inhibits PhIP-induced cytotoxicity in normal breast epithelial cells (MCF-10A). Curcumin significantly inhibited PhIP-induced DNA adduct formation and DNA double stand breaks with a concomitant decrease in reactive oxygen species (ROS) production. The expression of Nrf2, FOXO targets; DNA repair genes BRCA-1, H2AFX and PARP-1; and tumor suppressor P16 was studied to evaluate the influence on these core signaling pathways. PhIP induced the expression of various antioxidant and DNA repair genes. However, co-treatment with curcumin inhibited this expression. PhIP suppressed the expression of the tumor suppressor P16 gene, whereas curcumin co-treatment increased its expression. Caspase-3 and -9 were slightly suppressed by curcumin with a consequent inhibition of cell death. These results suggest that curcumin appears to be an effective anti-PhIP food additive likely acting through multiple molecular targets., (Published by Elsevier Ireland Ltd.)

microRNA-155 (miR-155) is one of the well-known oncogenic miRNA implicated in various types of tumors. Thiamine, commonly known as vitamin B1, is one of critical cofactors for energy metabolic enzymes including pyruvate dehydrogenase, alpha ketoglutarate dehydrogenase, and transketolase. Here we report a novel role of miR-155 in cancer metabolism through the up-regulation of thiamine in breast cancer cells. A bioinformatic analysis of miRNA array and metabolite-profiling data from NCI-60 cancer cell panel revealed thiamine as a metabolite positively correlated with the miR-155 expression level. We confirmed it in MCF7, MDA-MB-436 and two human primary breast cancer cells by showing reduced thiamine levels upon a knock-down of miR-155. To understand how the miR-155 controls thiamine level, a set of key molecules for thiamine homeostasis were further analyzed after the knockdown of miR-155. The results showed the expression of two thiamine transporter genes (SLC19A2, SLC25A19) as well as thiamine pyrophosphokinase-1 (TPK1) were decreased in both RNA and protein level in miR-155 dependent manner. Finally, we confirm the finding by showing a positive correlation between miR-155 and thiamine level in 71 triple negative breast tumors. Taken altogether, our study demonstrates a role of miR-155 in thiamine homeostasis and suggests a function of this oncogenic miRNA on breast cancer metabolism., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

The major goal of cancer therapy is to destroy cancer cells without harming normal cells. However, because cancer cells have incredible heterogeneity and adaptability, it is difficult to target them therapeutically. Metabolic reprogramming has emerged as a common feature of cancer. Ever since microRNAs (miRNAs) have been found to influence metabolism, researchers have been trying to address the connection between cancer cells and specific miRNAs. Many of the well-known miRNAs relate to crucial genes that can impact metabolic pathways, both negatively and positively. With a better understanding of how different pathways are affected, the roles of miRNAs will be more transparent, which could lead to the discovery of new ideas about the concept of tumorigenesis and other cancer-related topics., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Because of the abnormal vasculature, most growing solid tumors contain regions that experience either acute or chronic hypoxia. However, tumor cells can maintain a high glycolytic rate even when there is enough oxygen supply. Hypoxia-inducible factors (HIFs) play crucial role in the response of tumor cells to this distinct microenvironment by shifting energy production from mitochondria towards glycolysis. In this review, we focus on the metabolism of tumor cell survival in hypoxic microenvironments. Furthermore, we also emphasize the mechanisms by which hypoxia and HIFs regulate tumor metabolism., (Published by Elsevier Ireland Ltd.)

The role of microRNAs (miRNAs) in carcinogenesis as tumor suppressors or oncogenes has been widely reported. Epigenetic change is one of the mechanisms of transcriptional silencing of miRNAs in cancer. To identify lung cancer-related miRNAs that are mediated by histone modification, we conducted microarray analysis in the Calu-6 non-small cell lung cancer (NSCLC) cell line after treatment with suberoylanilide hydroxamic acid (SAHA), a histone deacetylase (HDAC) inhibitor. The expression level of miR-373 was enhanced by SAHA treatment in this cell line by microarray and the following quantitative RT-PCR analyses. Treatment with another HDAC inhibitor, Trichostatin A, restored the levels of miR-373 expression in A549 and Calu-6 cells, while demethylation drug treatment did not. Importantly, miR-373 was found to be down-regulated in NSCLC tissues and cell lines. Transfection of miR-373 into A549 and Calu-6 cells attenuated cell proliferation, migration, and invasion and reduced the expression of mesenchymal markers. Additional microarray analysis of miR-373-transfected cells and computational predictions identified IRAK2 and LAMP1 as targets of miR-373. Knockdown of these two genes showed similar biological effects to those of miR-373 overexpression. In clinical samples, overexpression of IRAK2 correlated with decreased disease-free survival of patients with non-adenocarcinoma. In conclusion, we found that miR-373 is silenced by histone modification in lung cancer cells and identified its function as a tumor suppressor and negative regulator of the mesenchymal phenotype through downstream IRAK2 and LAMP1 target genes., (Published by Elsevier Ireland Ltd.)

Cultures of primary tumors are very useful as a personalized screening system for effective therapeutic options. We here describe an effective method of reproducing human primary colon tumors through primary culture and a mouse xenograft model. A total of 199 primary colon tumor cultures were successfully established under optimized conditions to enrich for tumor cells and to expand it for long-term storage in liquid nitrogen. To examine whether these stored cultures retained original tumor properties, fifty primary cultures were xenografted into NOD-SCID mouse. Histological and tumor marker analysis of four representative tumor xenografts revealed that all of the xenograft retained its primary tumor characteristics. Oncomap analysis further showed no change in the major mutations in the xenografts, confirming that our method faithfully reproduced human colon tumors. A drug sensitivity assay revealed that two of the primary cultures were hypersensitive to oxaliplatin rather than 5-FU, which was used in the patients, suggesting it as an effective therapeutic option. We thus present an effective, reproducible preclinical model for testing various personalized therapeutic options in colon cancer patients., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Gastric cancer remains one of the leading causes of global cancer mortality. Multipotent gastric stem cells have been identified in both mouse and human stomachs, and they play an essential role in the self-renewal and homeostasis of gastric mucosa. There are several environmental and genetic factors known to promote gastric cancer. In recent years, numerous in vitro and in vivo studies suggest that gastric cancer may originate from normal stem cells or bone marrow-derived mesenchymal cells, and that gastric tumors contain cancer stem cells. Cancer stem cells are believed to share a common microenvironment with normal niche, which play an important role in gastric cancer and tumor growth. This mini-review presents a brief overview of the recent developments in gastric cancer stem cell research. The knowledge gained by studying cancer stem cells in gastric mucosa will support the development of novel therapeutic strategies for gastric cancer., (Published by Elsevier Ireland Ltd.)

Normal oxygen level is critical for niches that together with other components of the niche play vital role in regulating stem or tumor cells behavior. Hypoxia plays an important role in normal development and disease progression, including the growth of solid tumors. The hypoxia inducible factors (HIFs) are the key mediators of the cellular response to hypoxia. In this review, we focused on the role of HIFs on bone tumor formation. Further, we also emphasized how hypoxia, stem cells, and its niches regulate the bone tumorigenesis., (Published by Elsevier Ireland Ltd.)