Search

Background: Cisplatin is an important anticancer agent in cancer chemotherapy, but when resistant cells appear, treatment becomes difficult, and the prognosis is poor. Objective: In this study, we investigated the gene expression profile in cisplatin sensitive and resistant cells, and identified the genes involved in cisplatin resistance. Methods: Comparison of gene expression profiles revealed that UBE2L6 mRNA is highly expressed in resistant cells. To elucidate whether UBE2L6 is involved in the acquisition of cisplatin resistance, UBE2L6- overexpressing cells established from cisplatin-sensitive cells and UBE2L6-silenced cells developed from cisplatin- resistant cells were generated, and the sensitivity of cisplatin was examined. Results: The sensitivity of the UBE2L6-overexpressing cells did not change compared with the control cells, but the UBE2L6-silenced cells were sensitized to cisplatin. To elucidate the mechanism of UBE2L6 in cisplatin resistance, we compared the gene expression profiles of UBE2L6-silenced cells and control cells and found that the level of ABCB6 mRNA involved in cisplatin resistance was decreased. Moreover, ABCB6 promoter activity was partially suppressed in UBE2L6-silenced cells. Conclusion: These results suggest that cisplatin-resistant cells have upregulated UBE2L6 expression and contribute to cisplatin resistance by regulating ABCB6 expression at the transcriptional level. UBE2L6 might be a molecular target that overcomes cisplatin resistance.

The development of potent and selective therapeutic approaches to glioblastoma (GBM), one of the most aggressive primary brain tumors, requires identification of molecular pathways that critically regulate the survival and proliferation of GBM. Previous studies have reported that deregulated expression of N-myc downstream regulated gene 1 (NDRG1) affects tumor growth and clinical outcomes of patients with various types of cancer including glioma. Here, we show that high level expression of NDRG1 in tumors significantly correlated with better prognosis of patients with GBM. Loss of NDRG1 in GBM cells upregulated GSK3β levels and promoted cell proliferation, which was reversed by selective inhibitors of GSK3β. In contrast, NDRG1 overexpression suppressed growth of GBM cells by decreasing GSK3β levels via proteasomal degradation and by suppressing AKT and S6 cell growth signaling, as well as cell-cycle signaling pathways. Conversely, GSK3β phosphorylated serine and threonine sites in the C-terminal domain of NDRG1 and limited the protein stability of NDRG1. Furthermore, treatment with differentiation inducing factor-1, a small molecule derived from Dictyostelium discoideum, enhanced NDRG1 expression, decreased GSK3β expression, and exerted marked NDRG1-dependent antitumor effects in vitro and in vivo. Taken together, this study revealed a novel molecular mechanism by which NDRG1 inhibits GBM proliferation and progression. Our study thus identifies the NDRG1/GSK3β signaling pathway as a key growth regulatory program in GBM, and suggests enhancing NDRG1 expression in GBM as a potent strategy toward the development of anti-GBM therapeutics. Significance: This study identifies NDRG1 as a potent and endogenous suppressor of glioblastoma cell growth, suggesting the clinical benefits of NDRG1-targeted therapeutics against glioblastoma.

Background: We recently reported that WNT10A plays a pivotal role in wound healing by regulating collagen expression/synthesis, as the depletion of WNT10A dramatically delays skin ulcer formation. WNT signaling also has a close correlation with the cancer microenvironment and proliferation, since tumors are actually considered to be 'unhealing' or 'overhealing' wounds. To ascertain the in vivo regulatory functions of WNT10A in tumor growth, we examined the net effects of WNT10A depletion using Wnt10a-deficient mice (Wnt10a -/-). Methods and Results: We subjected C57BL/6J wild-type (WT) or Wnt10a -/- mice to murine melanoma B16-F10 cell transplantation. Wnt10a -/- mice showed a significantly smaller volume of transplanted melanoma as well as fewer microvessels and less collagen expression and more necrosis than WT mice. Conclusions: Taken together, our observations suggest that critical in vivo roles of Wnt10a-depleted anti-stromagenesis prevent tumor growth, in contrast with true wound healing/scarring.

Y-box binding protein 2 (YBX2) has been associated with the properties of both germ cells and cancer cells. We hypothesized that YBX2 might contribute to the characteristics of cancer stem cells (CSCs). In this study, we clarified the function of YBX2 in endometrial cancer stem cells. We established a human YBX2-expressing Ishikawa (IK) cell line (IK-YBX2 cells). We analyzed gene expression associated with stemness and isolated SP cells from IK-YBX2 cells. The SP population of IK-YBX2 cells, the expression of ALDH1 and serial sphere-forming capacity were associated with levels of YBX2 expression. IK-YBX2 cells were resistant to anti-cancer drugs. In gene expression analysis, a gene for cancer testis antigen, CT45, was generally overexpressed in IK-YBX2 cells. YBX2-mediated CT45 expression was associated with increased levels of self-renewal capacity and paclitaxel resistance. The level of CT45 expression was enhanced in high-grade and/or advanced stages of human endometrial cancer tissues. We conclude that expression of YBX2 is essential for the stem cell-like phenotype. CT45 contributes to stemness associated with YBX2 and might be related to the progression of endometrial cancer.

Antisense oligonucleotides (AS-ODNs) specifically hybridize with target mRNAs, resulting in interference with the splicing mechanism or the regulation of protein translation. In our previous reports, we demonstrated that β-glucan schizophyllan (SPG) can form a complex with AS-ODNs attached with oligo deoxyadenosine dA40 (AS-ODN-dA40/SPG), and that this complex can be recognized by β-glucan receptor Dectin-1 on antigen presenting cells and lung cancer cells. In many types of cancer cell, activating K-ras mutations related to malignancy are frequently observed. In this study, we first designed 78 AS-ODNs for K-ras to optimize the sequence for highly efficient gene suppression. The selected AS-ODN (K-AS07) having dA40 made a complex with SPG. The resultant complex (K-AS07-dA40/SPG) showed an effect of silencing the ras gene in the cells (PC9: human adenocarcinoma differentiated from lung tissue) expressing Dectin-1, leading to the suppression of cell growth. Furthermore, the cytotoxic effect was enhanced when used in combination with the anticancer drug gemcitabine. Gemcitabine, a derivative of cytidine, was shown to interact with dA40 in a sequence-dependent manner. This interaction did not appear to be so strong, with the gemcitabine being released from the complex after internalization into the cells. SPG and the dA40 part of K-AS07-dA40 play roles in carriers for K-AS07 and gemcitabine, respectively, resulting in a strong cytotoxic effect. This combination effect is a novel feature of the AS-ODN-dA40/SPG complexes. These results could facilitate the clinical application of these complexes for cancer treatment.

It was reported that statins, inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase that are used to prevent hypercholesterolemia, have antitumor activity in several cancers. In this study, we investigated the cell viability of statins in Cisplatin-resistant HCP4 and PCDP5 cells compared with their parent Hela and PC3 cells, respectively, and found that HCP4 and PCDP5 cells were 37-fold and 18-fold more resistant to Cisplatin but 13-fold and 7-fold more sensitive to Lovastatin by cell proliferation assay. Lovastatin induced the apoptosis of HCP4 cells more rapidly and to greater extent than in Hela cells as assessed by flow cytometry and western blotting analyses. The MVA pathway was not involved in this acquired Cisplatin resistance. To elucidate the mechanism underlying the reduced viability to Lovastatin, we performed cDNA microarray analysis and identified 65 and 54 genes that were induced more than 2-fold by Lovastatin in HCP4 and PCDP5 cells, respectively. Of these, only three genes, KLF2, KLF6, and RHOB, were commonly induced between HCP4 and PCDP5 cells. These mRNAs were strongly induced by Lovastatin with transcriptional regulation in HCP4 cells. Consistent with transcription, the protein expression of RHOB also was induced by Lovastatin. The induction of these genes was associated with cell cycle arrest and apoptosis. Combination treatment with Cisplatin and Lovastatin resulted in an agonistic effect in Hela and PC3 cells and an antagonistic effect in HCP4 and PCDP5 cells. These results suggest that statins might have the potential to overcome Cisplatin resistance as single-agent therapy.

// Asumi Iesato 1 , Teruo Nakamura 1 , Hiroto Izumi 2 , Takeshi Uehara 3 and Ken-Ichi Ito 1 1 Division of Breast, Endocrine and Respiratory Surgery, Department of Surgery (II), Shinshu University School of Medicine, Matsumoto, Japan 2 Department of Occupational Pneumology, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Kitakyushu, Japan 3 Department of Laboratory Medicine, Shinshu University School of Medicine, Matsumoto, Japan Correspondence to: Ken-Ichi Ito, email: kenito@shinshu-u.ac.jp Keywords: thyroid cancer, PATZ1, dedifferentiation, invasion, migration Received: February 25, 2017 Accepted: June 28, 2017 Published: August 02, 2017 ABSTRACT This study was designed to examine the involvement of PATZ1 in carcinogenesis and dedifferentiation of thyroid cancer. Immunohistochemistry on clinical specimens indicated nuclear PATZ1 expression in all normal thyroid glands and adenomatous goiter, while nuclear PATZ1 expression decreased along with the dedifferentiation of thyroid cancer. Knockdown of nuclear PATZ1 by siRNA in an immortalized normal follicular epithelial cell line (Nthy-ori 3-1) altered cellular morphology and significantly increased cell proliferation, migration, and invasion. In addition, the expression of urokinase-type plasminogen activator (uPA), matrix metalloproteinase (MMP) 2, MMP9, and MMP11 was increased by PATZ1 knockdown in Nthy-ori 3-1 cells. When PATZ1 was silenced in differentiated thyroid cancer (DTC) cell lines (TPC-1 and FTC-133), proliferation, cellular motility, and expression of uPA and MMPs were significantly increased. Forced expression of exogenous PATZ1 decreased proliferation, cellular motility, and the expression of uPA and MMPs in ATC cell lines (ACT-1 and FRO). In thyroid cancer cell lines, PATZ1 functioned as a tumor suppressor regardless of p53 status. Moreover, the ratio of nuclear PATZ1 positive tumors was significantly decreased in ATC irrespective of p53 status. Our study demonstrates that PATZ1 knockdown enhances malignant phenotype both in thyroid follicular epithelial cells and thyroid cancer cells, suggesting that PATZ1 functions as a tumor suppressor in thyroid follicular epithelial cells and is involved in the dedifferentiation of thyroid cancer.

Zinc‐finger protein 143 (ZNF143) is a transcription factor that is involved in anticancer drug resistance and cancer cell survival. In the present study, we identified a novel small molecule N‐(5‐bromo‐2‐methoxyphenyl)‐3‐(pyridine‐3‐yl) propiolamide (YPC‐21661) that inhibited ZNF143 promoter activity and down‐regulated the expression of the ZNF143‐regulated genes, RAD51, PLK1, and Survivin, by inhibiting the binding of ZNF143 to DNA. In addition, YPC‐21661 was cytotoxic and induced apoptosis in the human colon cancer cell line, HCT116 and human prostate cancer cell line, PC‐3. 2‐(pyridine‐3‐ylethynyl)‐5‐(2‐(trifluoromethoxy)phenyl)‐1,3,4‐oxadiazole (YPC‐22026), a metabolically stable derivative of YPC‐21661, induced tumor regression accompanied by the suppression of ZNF143‐regulated genes in a mouse xenograft model. The present study revealed that the inhibition of ZNF143 activity by small molecules induced tumor regression in vitro and in vivo; therefore, ZNF143 is a promising target of cancer therapeutics.

Endocrine therapies effectively improve the outcomes of patients with estrogen receptor (ER)-positive breast cancer. However, the emergence of drug-resistant tumors creates a core clinical challenge. In breast cancer cells rendered resistant to the antiestrogen fulvestrant, we defined causative mechanistic roles for the transcription factor YBX1 and the levels of ER and the ERBB2 receptor. Enforced expression of YBX1 in parental cells conferred resistance against tamoxifen and fulvestrant in vitro and in vivo. Furthermore, YBX1 overexpression was associated with decreased and increased levels of ER and ERBB2 expression, respectively. In antiestrogen-resistant cells, increased YBX1 phosphorylation was associated with a 4-fold higher degradation rate of ER. Notably, YBX1 bound the ER, leading to its accelerated proteasomal degradation, and induced the transcriptional activation of ERBB2. In parallel fashion, tamoxifen treatment also augmented YBX1 binding to the ERBB2 promoter to induce increased ERBB2 expression. Together, these findings define a mechanism of drug resistance through which YBX1 contributes to antiestrogen bypass in breast cancer cells. Cancer Res; 77(2); 545–56. ©2016 AACR.

Nuclear expression of Y-box–binding protein (YBX1) is closely correlated with clinical poor outcomes and drug resistance in breast cancer. Nuclear translocation of YBX1 is facilitated by YBX1 phosphorylation at serine 102 by AKT, p70S6K, and p90RSK, and the phosphorylated YBX1 (pYBX1) promotes expression of genes related to drug resistance and cell growth. A forthcoming problem to be addressed is whether targeting the phosphorylation of YBX1 overcomes antiestrogen resistance by progressive breast cancer. Here, we found that increased expression of pYBX1 was accompanied by acquired resistance to antiestrogens, fulvestrant and tamoxifen. Forced expression of YBX1/S102E, a constitutive phosphorylated form, resulted in acquired resistance to fulvestrant. Inversely, YBX1 silencing specifically overcame antiestrogen resistance. Furthermore, treatment with everolimus, an mTORC1 inhibitor, or TAS0612, a novel multikinase inhibitor of AKT, p70S6K, and p90RSK, suppressed YBX1 phosphorylation and overcame antiestrogen resistance in vitro and in vivo. IHC analysis revealed that expression of pYBX1 and YBX1 was augmented in patients who experienced recurrence during treatment with adjuvant endocrine therapies. Furthermore, pYBX1 was highly expressed in patients with triple-negative breast cancer compared with other subtypes. TAS0612 also demonstrated antitumor effect against triple-negative breast cancer in vivo. Taken together, our findings suggest that pYBX1 represents a potential therapeutic target for treatment of antiestrogen-resistant and progressive breast cancer.

Aurora kinase B (AURKB) inhibitors are regarded as potential molecular-targeting drugs for cancer therapy. The present study evaluated the cytotoxic effect of a combination of AZD1152-hQPA, an AURKB inhibitor, and various anticancer agents on the HeLa human cervical cancer cell line, as well as its cisplatin-resistant equivalent HCP4 cell line. It was demonstrated that AZD1152-hQPA had an antagonistic effect on the cytotoxicity of cisplatin, etoposide and doxorubicin, but had a synergistic effect on that of all-trans-retinoic acid (ATRA), Am80 and TAC-101, when tested on HeLa cells. Cisplatin, etoposide and doxorubicin were shown to increase the cellular expression of AURKB, while ATRA, Am80 and TAC-101 downregulated its expression. These results suggested that AURKB expression is regulated by these anticancer agents at the transcriptional level, and that the level of expression of AURKB may influence the cytotoxic effect of AZD1152-hQPA. Therefore, when using anticancer agents, decreasing the expression of AURKB using a molecular-targeting drug may be an optimal therapeutic strategy.

Silencing Y-box binding protein 1 (YB-1) can be an excellent target for cancer therapy and many lung cancer cells express the polysaccharide-recognition receptor Dectin-1. We designed a Dectin-1 targeting vehicle delivering YB-1-antisense DNA. First, we selected five optimal antisense DNA sequences to silence YB-1 from among 153 candidates. We chose the sequence closest to the start codon (AS014), and attached dA40 to the 3' end; dA40 promotes complex formation with a β-(1➝3)-d-glucan called schizophyllan (SPG). The resultant complexes were applied to 12 human-oriented lung cancer cell lines, and cell viability was examined. The cell lines exhibited decreased viability and showed strong affinity to bind SPG, suggesting the AS014/SPG complex entered the cells via the Dectin-1 mediated pathway.

Antisense oligonucleotides (AS-ODNs) hybridize with specific mRNAs, resulting in interference with the splicing mechanism or the regulation of protein translation. We previously demonstrated that the β-glucan schizophyllan (SPG) can form a complex with AS-ODNs with attached dA40 (AS-ODNs/SPG), and this complex can be incorporated into cells, such as macrophages and dendritic cells, expressing the β-glucan receptor Dectin-1. We have achieved efficient gene silencing in animal models, but the uptake mechanism and intracellular distribution are unclear. In this study, we prepared the complex consisting of SPG and AS-ODNs (AS014) for Y-box binding protein-1 (YB-1). After treatment with endocytosis inhibitor Pitstop 2 and small interfering RNA targeting Dectin-1, we found that AS014/SPG complexes are incorporated into cells by Dectin-1-mediated endocytosis and inhibit cell growth in a Dectin-1 expression level-dependent manner. After treatment with AS014/SPG complexes, we separated the cell lysate into endosomal and cytoplasmic components by ultracentrifugation and directly determined the distribution of AS014 by reverse transcription PCR using AS014 ODNs as a template or a reverse transcription primer. In the cytoplasm, AS014 clearly hybridized with YB-1 mRNAs. This is the first demonstration of the distinct distribution of the complex in cells. These results could facilitate the clinical application of the complex.

The polypeptide N-acetylgalactosaminyltransferase (GalNAc-Ts) family of enzymes regulates the critical initial steps of mucin-type O-glycosylation. Among GalNAc-Ts that may significantly influence cancer biology, thus affecting cell differentiation, adhesion, invasion, and/or metastasis, GalNAc-T3 exhibits a high expression in several human cancers, closely associated with tumor progression and a poor prognosis. However, the expression pattern of GalNAc-T3 in oral squamous cell carcinoma (OSCC) remains obscure. Since postoperative recurrence of even early stage OSCC (ESOSCC) occurs at an early phase, significantly affecting their clinical course and worse outcome, the identification of clinically significant accurate biomarkers is needed. Therefore, we investigated the correlation between the immunohistochemical GalNAc-T3 expression and various clinicopathological characteristics and recurrence using 110 paraffin-embedded tumor samples obtained from patients with surgically resected ESOSCC (T1–2N0). Recurrence was recognized in 37 of 110 (33.6 %) patients. The GalNAc-T3 expression was considered to be strongly positive when 20 % or more of the cancer cells showed positive cytoplasmic staining. Consequently, a strong expression of GalNAc-T3 was observed in 40 patients (36.4 %), showing a close relationship to poor differentiation, the presence of lymphatic and vascular invasion, and recurrence. Univariate and multivariate analyses further demonstrated that the patients with a strong GalNAc-T3+ status had markedly lower disease-free survival (DFS) rates, especially within the first 2 years postoperatively. Therefore, GalNAc-T3 might play a role in the pathogenesis of ESOSCC recurrence, and its immunohistochemical detection potentially predicts a shorter DFS and may be a useful parameter for providing clinical management against ESOSCC in the early postoperative phase. Electronic supplementary material The online version of this article (doi:10.1007/s13277-015-3928-7) contains supplementary material, which is available to authorized users.

The SMARCE1 (SWI / SNF-related, matrix-associated, and actin-dependent regulator of chromatin, subfamily e, member 1) encodes BAF57 protein. Previously, we reported that BAF57 is a predictive marker of endometrial carcinoma. In this study, we investigated BAF57 expression in ovarian cancer cell lines and their sensitivities to cisplatin, doxorubicin, paclitaxel, and 5-fluorouracil. BAF57 expression was strongly correlated with sensitivities to cisplatin, doxorubicin, and 5-fluorouracil in 10 ovarian cancer cell lines. Paclitaxel sensitivity was also correlated with BAF57 expression, but without significance. In A2780 ovarian cancer cells, knockdown of BAF57 using specific siRNA increased cell cycle arrest at G1 phase and the sensitivities to these anticancer agents. cDNA microarray analysis of A2780 cells transfected with BAF57 siRNA showed that 134 genes were positively regulated by BAF57, including ATP-binding cassette, sub-family G (WHITE), member 2 (ABCG2) encoding breast cancer resistance protein (BCRP). We confirmed that knockdown of BAF57 decreased BCRP expression in ovarian cancer cells by Western blot analysis, and that ABCG2 gene expression might be regulated transcriptionally. These results suggested that BAF57 is involved in ovarian cancer cell growth and sensitivity to anticancer agents, and that BAF57 may be a target for ovarian cancer therapy.

Background/aim Mitochondrial transcription factor A (mtTFA) is necessary for both the transcription and maintenance of mitochondrial DNA (mtDNA). The present study investigated the clinical significance of mtTFA in patients with right- and left-sided colorectal cancer (CRC). Patients and methods Surgical specimens from 237 CRC patients were immunohistochemically stained with polyclonal anti-mtTFA antibody. The relationships among the mtTFA expression, clinicopathological factors and prognosis were evaluated. Results Thirty-five (60.3%) of 58 right-sided CRC patients and 82 (45.8%) of 179 left-sided CRC patients showed high mtTFA expression. The mtTFA expression significantly correlated with lymph node metastasis, distant metastasis, the TNM stage and lymphatic invasion in left-sided CRC patients and did not correlate with any factors in right-sided CRC patients. Univariate and multivariate analyses revealed the mtTFA expression to be a significant prognostic factor in left-sided CRC patients but not in right-sided CRC patients. Conclusion These results suggest that a high mtTFA expression is a useful marker for tumor progression and a poor prognosis in left-sided CRC patients.

BACKGROUND The aberrant glycosylation of mucin type O-glycans is thought to be associated with functional alteration of cancer cells, including adhesive properties, as well as their potential for invasion and metastasis. Positive expression of N-acetylgalactosaminyltransferase-6 (GalNAc-T6) may also be a marker for aberrant O-glycans in carcinogenesis. We previously reported that over-expression of GalNAc-T6 had a strong association with endometrial cell invasion ability in vitro. MATERIALS AND METHODS This study investigated the relationship between GalNAc-T6 expression and cell adhesion molecules in 218 endometrial carcinomas by immunohistochemistry. RESULTS Expression of GalNAc-T6 was found to be significantly related to expression of E-cadherin. Positive expression of GalNAc-T6 was significantly associated with better histological grade and good clinical prognosis of patients, but positive E-cadherin and β-catenin expression were not significantly associated with improved overall survival. CONCLUSION GalNAc-T6 might be related to cell-cell adhesion in the early phase of cancer invasion in endometrial carcinoma.

Background: The transcription factor, zinc finger protein 143 (ZNF143), positively regulates many cell-cycle-related genes. The ZNF143 would show high expression of multiple solid tumours related closely to cancer cell growth, similar to the widely accepted Ki67 (MIB-1) protein, but the underlying mechanisms for ZNF143 remain unclear. We investigated the association of ZNF143 expression with clinicopathological features and prognoses of patients with lung adenocarcinoma. Methods: Expressions of ZNF143 and MIB-1 were immunohistochemically analysed in 183 paraffin-embedded tumour samples of patients with lung adenocarcinoma. The ZNF143 expression was considered to be strong when >30% of the cancer cells demonstrated positive staining. Results: Strong ZNF143+ expression showed a significantly close relationship to pathologically moderate to poor differentiation and highly invasive characteristics. The ZNF143 positivity potentially induced cell growth of lung adenocarcinoma, correlated significantly with high MIB-1 labelling index (⩾10%). Univariate and multivariate analyses demonstrated that both strong ZNF143+ and the high MIB-1 index group have only and significantly worse survival rates. Conclusions: The combination of strong ZNF143 expression and high MIB-1 index potentially predicts high proliferating activity and poor prognosis in patients with lung adenocarcinoma, and may offer a therapeutic target against ZNF143.

// Koichi Azuma 1 , Akihiko Kawahara 2 , Kahori Sonoda 3 , Kazutaka Nakashima 2 ,Kousuke Tashiro 4 , Kosuke Watari 3 , Hiroto Izumi 5 , Masayoshi Kage 2 , Michihiko Kuwano 6 , Mayumi Ono 3 and Tomoaki Hoshino 1 1 Division of Respirology, Neurology, and Rheumatology, Department of Internal Medicine, Kurume University School of Medicine, Kurume, Fukuoka, Japan 2 Department of Diagnostic Pathology, Kurume University Hospital, Kurume, Fukuoka, Japan 3 Department of Pharmaceutical Oncology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan 4 Department of Bioscience and Biotechnology, Kyushu University, Fukuoka, Japan 5 Department of Occupational Pneumology, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Kitakyushu, Japan 6 Laboratory of Molecular Cancer Biology, Department of Clinical Pharmaceutics, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan Correspondence: Koichi Azuma, email: // Keywords : activating EGFR mutation, FGFR1, non-small cell lung cancer, afatinib Received : January 31, 2014 Accepted : March 24, 2014 Published : March 26, 2014 Abstract Most NSCLC patients with EGFR mutations benefit from treatment with EGFR-TKIs, but the clinical efficacy of EGFR-TKIs is limited by the appearance of drug resistance. Multiple kinase inhibitors of EGFR family proteins such as afatinib have been newly developed to overcome such drug resistance. We established afatinib-resistant cell lines after chronic exposure of activating EGFR mutation-positive PC9 cells to afatinib. Afatinib-resistant cells showed following specific characteristics as compared to PC9: [ 1 ] Expression of EGFR family proteins and their phosphorylated molecules was markedly downregulated by selection of afatinib resistance; [ 2 ] Expression of FGFR1 and its ligand FGF2 was alternatively upregulated; [ 3 ] Treatment with anti-FGF2 neutralizing antibody blocked enhanced phosphorylation of FGFR in resistant clone; [ 4 ] Both resistant clones showed collateral sensitivity to PD173074, a small-molecule FGFR-TKIs, and treatment with either PD173074 or FGFR siRNA exacerbated suppression of both afatinib-resistant Akt and Erk phosphorylation when combined with afatinib; [ 5 ] Expression of twist was markedly augmented in resistant sublines, and twist knockdown specifically suppressed FGFR expression and cell survival. Together, enhanced expression of FGFR1 and FGF2 thus plays as an escape mechanism for cell survival of afatinib-resistant cancer cells, that may compensate the loss of EGFR-driven signaling pathway.

The aurora kinases are serine/threonine kinases that are essential for mitosis and contribute to tumorigenesis. Therefore, aurora kinases hold promise for molecularly targeted therapy. In the present study, we demonstrated that aurora B kinase (AURKB) is overexpressed in both cisplatin- and oxaliplatin-resistant cells. Downregulation of AURKB sensitized cells to both cisplatin and oxaliplatin, but not to paclitaxel, 5-FU or hydrogen peroxide. Interestingly, we found that both cisplatin- and oxaliplatin-resistant cells were hypersensitive to the AURKB specific inhibitors, AZD1152 HQPA and ZM447439, suggesting that both cisplatin- and oxaliplatinresistant cells develop an addiction to AURKB. These data provide evidence that aurora kinase inhibitors can overcome both cisplatin and oxaliplatin resistance. Therefore, AURKB inhibitors could offer potential benefits if used after first-line platinum-based chemotherapy.

Department of Internal Medicine, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501, Japan Department of Thoracic Surgery, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501, Japan Department of Pathology, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501, Japan Department of Molecular Biology, University of Occupational and Environmental Health, Kitakyushu, Fukuoka 807-8555, Japan Department of Pharmacology, Takasaki University of Health and Welfare, Takasaki 370-0033, Japan

Background: The polypeptide N-acetylgalactosaminyltransferases (GalNAc-Ts) family of enzymes regulates the initial steps of mucin-type O-glycosylation. N-acetylgalactosaminyltransferases might show novel patterns of GalNAc-T glycosylation on tumour-derived proteins, which could influence cancer biology, but its mechanisms are unclear. We investigated the association of GalNAc-T3 and -T6 expressions with clinicopathological features and prognoses of patients with renal cell carcinomas (RCCs). Methods: Expressions of GalNAc-T3/6 and cell-adhesion molecules were analysed immunohistochemically in 254 paraffin-embedded tumour samples of patients with RCC. Results: Of 138 GalNAc-T3+ cases, 46 revealed significant co-expression with GalNAc-T6. N-acetylgalactosaminyltransferases-3+ expression showed a close relationship to poor clinical performance and large tumour size, or pathologically high Fuhrman's grading, and presence of vascular invasion and necrosis. The GalNAc-T3-positivity potentially suppressed adhesive effects with a significantly low β-catenin expression. Univariate and multivariate analyses showed the GalNAc-T3+ group, but not the GalNAc-T6+ group, to have significantly worse survival rates. Conclusion: N-acetylgalactosaminyltransferases-3 expression independently predicts high-grade tumour and poor prognosis in patients with RCC, and may offer a therapeutic target against RCC.

Background The most significant cause of gastric cancer (GC) death is metastasis, although the underlying mechanisms remain obscure. Y-box binding protein-1 (YB-1) is associated with tumor aggressiveness and poor prognosis in various cancers. In this study we investigated the relationship between YB-1 expression and the clinicopathologic features and metastasis-associated epithelial–mesenchymal transition (EMT) phenotype in advanced GC patients. Patients and Methods Immunohistochemistry (IHC) was used to analyze YB-1, E-cadherin, and vimentin expression in 98 advanced GC cases. Results Twenty-nine (29.6%) cases of GC exhibited strong YB-1 immunoreactivity. Strong YB-1 staining occurred more often in patients with intestinal or non-scirrhous cancer, and demonstrated a significant correlation with vascular invasion (VI), liver metastasis, and shorter disease-free survival (DFS). However, we observed no relationship between YB-1 expression and EMT phenotype or overall survival. Logistic regression analysis revealed that strong staining for YB-1 was the only predictive factor for liver metastasis. Conclusions Our results indicate that YB-1 plays a role in the process of GC metastasis, and that the immunohistochemical detection of this protein potentially delivers valuable insight regarding the prediction of liver metastasis and shorter DFS in patients undergoing curative resection for advanced GC. J. Surg. Oncol. 2012; 105:724–730. © 2012 Wiley Periodicals, Inc.

We previously reported that the transcription factor Zinc Finger Protein 143 (ZNF143) regulates the expression of genes associated with cell cycle and cell division, and that downregulation of ZNF143 induces cell cycle arrest at G2/M. To assess the function of ZNF143 expression in the cell cycle, we established two cells with forced expression of ZNF143 derived from PC3 prostate cancer cell lines. These cell lines overexpress genes associated with cell cycle and cell division, such as polo-like kinase 1 (PLK1), aurora kinase B (AURKB) and some minichromosome maintenance complex components (MCM). However, the doubling time of cells with forced expression of ZNF143 was approximately twice as long as its control counterpart cell line. Analysis following serum starvation and re-seeding showed that PC3 cells were synchronized at G1 in the cell cycle. Also, ZNF143 expression fluctuated, and was at its lowest level in G2/M. However, PC3 cells with forced expression of ZNF143 synchronized at G2/M, and showed lack of cell cycle-dependent fluctuation of nuclear expression of MCM proteins. Furthermore, G2/M population of both cisplatin-resistant PCDP6 cells over-expressing ZNF143 (derived from PC3 cells) and cells with forced expression of ZNF143 was significantly higher than that of each counterpart, and the doubling time of PCDP6 cells is about 2.5 times longer than that of PC3 cells. These data suggested that fluctuations in ZNF143 expression are required both for gene expression associated with cell cycle and for cell division.

Background: The family of polypeptide N-acetylgalactosaminyltransferases (GalNAc-Ts) is responsible for the altered glycosylation in cancer. The purpose of our study was to investigate the clinical significance of two isoforms, GalNAc-T6 and -T3, and their correlation with the prognosis of pancreatic cancer. Methods: Immunohistochemistry was used to analyse GalNAc-T6 and -T3 expressions in 70 clinicopathologically characterised pancreatic cancer cases. Results: Positive expressions of GalNAc-T6 and -T3 were immunohistochemically identified in 51% (36 of 70) and in 77% (54 of 70) of patients, respectively. A close relationship was noted between GalNAc-T6 positive expression and pathological well/moderate differentiated type (P=0.001), small tumour size (P=0.044), absence of vascular invasion (P=0.009), and low stage of the American Joint Committee on Cancer systems (P=0.043). The expression of GalNAc-T3 significantly correlated with good differentiation (P=0.001), but not with other clinicopathologic features. Furthermore, univariate and multivariate analyses revealed that GalNAc-T6 expression was an independent prognosis indicator for the disease, whereas GalNAc-T3 expression had no impact on clinical outcome, even though 33 of 36 GalNAc-T6-positive cases also had a positive expression of GalNAc-T3 (P=0.001, r=0.356). Conclusion: Both GalNAc-T6 and -T3 expressions correlated significantly with tumour differentiation, whereas only GalNAc-T6 expression predicted prognosis in pancreatic cancer.

Cancer cells show constitutive upregulation of glycolysis, and the concentration of lactate thus produced correlates with prognosis. Here, we examined whether lactate concentration and lactate transporter expression are related to migration and invasion activity. We found that the expression of the monocarboxylate transporters MCT1 and MCT4, but not MCT5, in human lung cancer cell lines was significantly correlated with invasiveness. To clarify the effects of MCT1 and MCT4 expression on invasion, we performed migration and invasion assays after transfection with siRNA specific for MCT1 or MCT4. Knockdown of MCT1 or MCT4 did not influence cell migration but reduced invasion; this was also observed for knockdown of the lactate transporter-associated protein basigin. We also demonstrated that both expression and activity of MMP9 and MMP2 were not correlated with invasion activity and not regulated by MCT1, MCT4 and basigin. Furthermore, the addition of lactate did not increase migration and invasion activity, but low concentration of 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS), a general anion channel blocker, as well as other MCT inhibitors quercetin and simvastatin, inhibited cell invasion without influencing migration activity and the cellular expression of MCT1 and MCT4. This is the first report suggesting that lactate transporters are involved in human cancer cell invasiveness. As such, these proteins may be promising targets for the prevention of cancer invasion and metastasis.

We previously reported that mitochondrial transcription factor A (mtTFA) preferentially recognizes cisplatin-damaged DNA via physical interaction with p53 and is upregulated by treatment with cisplatin and fluorouracil (5-FU). The aim of the present study was to evaluate whether expression of mtTFA predicts the clinical outcome in patients with metastatic colorectal cancer treated with modified 5-fluorouracil, leucovorin and oxaliplatin 6 (mFOLFOX6). Fifty-nine patients with metastatic lesions from colorectal cancer treated with mFOLFOX6 were included in this study. The subjects consisted of 25 women and 34 men with a median age of 62 years. The patients were treated with oxaliplatin (85 mg/m(2) ) plus leucovorin (200 mg/m(2) ) as a 2-h infusion on day 1, followed by 5-FU (400 mg/m(2) ) bolus and 46-h continuous infusion of 2400 mg/m(2) . The expressions of mtTFA and p53 of resected primary tumors were examined by immunohistochemical analysis. Of the 59 patients, 33 (complete response 1, partial response 32) achieved a confirmed response to therapy. The positive cytoplasmic staining rate for mtTFA was 44.1% and that for p53 was 59.3%, respectively. Strong expression of mtTFA was detected in eight of 33 complete response/partial response (24.2%) and in 18 of 26 SD/PD (69.2%), indicating that mtTFA expression was significantly correlated with response to chemotherapy (P

Cisplatin is a potent and pivotal anticancer drug in the treatment of various solid tumors including head and neck cancers. Since the beginning of its clinical use in the early 1980s, cisplatin has been one of the most prevailing and reliable anticancer drugs. Its major limitation, however, is the development of resistance during the courses of chemotherapy. The mode of action of cisplatin is mediated by the formation of DNA adducts, which activate several signal transduction pathways, eventually leading to cellular apoptosis. Cisplatin resistance depends on a number of factors that reduce drug uptake, promote cytoplasmic detoxification, and increase DNA repair activity. We herein review a novel mechanism of cisplatin resistance involving the transcriptional regulation of DNA repair genes by ZNF143. ZNF143 is overexpressed in cisplatin-resistant cells, and its knockdown increases sensitivity to cisplatin but not to oxaliplatin, etoposide, or vincristine. We show that ZNF143 is associated with p73, but not with p53. p73 enhances the action of ZNF143 by facilitating the binding of ZNF143 to ZNF143 binding sites and cisplatin-modified DNA. We further present direct evidence that DNA repair genes, Rad51 and FEN-1, are targeted by ZNF143 and overexpressed in cisplatin-resistant cells. These lines of evidence indicate that the interplay among ZNF143, p73, and ZNF143 target DNA repair genes is responsible for cisplatin resistance. Prediction of cisplatin sensitivity and molecular targeted therapy for ZNF143 remain to be conducted in future basic and clinical studies for managing cisplatin-resitant cancers.

Gefitinib (Iressa) and erlotinib (Tarceva), which target the epidermal growth factor receptor (EGFR), are approved for treatment of patients with advanced non–small cell lung cancer (NSCLC). Patients whose tumors harbor mutations in the EGFR gene, including delE746-A750 in exon 19 and L858R in exon 21, may benefit in particular from gefitinib treatment. However, acquired resistance to gefitinib has been a serious clinical problem, and further optimization is needed for application of EGFR-targeted drugs in lung cancer patients. In this study, we established gefitinib-resistant NSCLC cells from PC-9 cell line, which harbors the delE746-A750 mutation, by exposing the cell line to gefitinib for over 7 months. Gefitinib-resistant PC-9/GEFs cell lines showed a marked downregulation of PTEN expression and increased Akt phosphorylation. In revertant, gefitinib-sensitive clones (PC-9/Rev) derived from PC-9/GEF1-1 and PC-9/GEF2-1, PTEN expression, as well as sensitivity to gefitinib and erlotinib, was restored. Knockdown of PTEN expression using small interfering RNA specific for PTEN in PC-9 cells resulted in drug resistance to gefitinib and erlotinib. Nuclear translocation of the EGR1 transcription factor, which regulates PTEN expression, was shown to be suppressed in resistant clones and restored in their revertant clones. Reduced PTEN expression was also seen in tumor samples from a patient with gefitinib-refractory NSCLC. This study thus strongly suggests that loss of PTEN expression contributes to gefitinib and erlotinib resistance in NSCLC. Our findings reinforce the therapeutic importance of PTEN expression in the treatment of NSCLC with EGFR-targeted drugs. Cancer Res; 70(21); 8715–25. ©2010 AACR.

Mina53, a novel target gene product of c-Myc, is overexpressed in various malignancies. We previously demonstrated that Mina53 is overexpressed in lung cancer patients from the early clinical stages. In this paper, the association between disease prognosis and Mina53 expression in lung cancer patients is analyzed; we found that overexpression of Mina53 in lung cancer patients is associated with favorable prognosis. Statistical analysis using the Kaplan–Meier method showed that patients with negative staining for Mina53 had significantly shorter survival than patients with positive staining for Mina53, especially in stage I or with squamous cell carcinoma. Because the major cause of death in lung cancer patients after surgery is distant metastasis, the effect on cancer cell invasiveness was analyzed for the mechanisms involved in the association with favorable outcome. Overexpression of Mina53 in H226B, a lung squamous cell carcinoma cell line, inhibited cancer cell invasion. Transfection with mina53 shRNA increased the number of invading cells. These results suggest that Mina53 immunostaining is a useful prognostic marker – especially in the early stage of lung cancer – and that Mina53 negative patients should be managed particularly carefully after surgery.

Eribulin (ERI), an inhibitor of microtubule dynamics, is a key drug for metastatic breast cancer. While HDAC inhibitors have been shown to presents antitumor effect for various malignancies. Among HDAC family, HDAC6 is known as a deacetylase of tubulin. To develop a novel therapeutic strategy for triple negative breast cancer (TNBC), we tested the combinational effect of ERI and HDAC inhibitor for TNBC cells in vitro. Two TNBC cell lines (MDA-MB-231, Hs578T) and their ERI-resistant cells (MDA-MB-231/E, Hs578T/E) established in our laboratory were used in the study. Vorinostat (VOR), a pan-HDAC inhibitor, and ricolinostat (RICO), a selective HDAC6 inhibitor were used. The sensitivity to VOR or RICO was not different between the parental and the ERI-resistant cells. In the protein expression analysis, HDAC6 expression was not altered between parental and ERI-resistant cells. Prior treatment with VOR or RICO increased the expression of acetylatedα-tubulin in both parental and ERI-resistant TNBC cell lines. When low concentration of VOR (0.5 μM) or RICO (0.5 μM) was added simultaneously with ERI, the sensitivity to ERI was enhanced significantly in both parental MDA-MB-231 and Hs578T cell lines. Furthermore, when both parental cell lines were treated with VOR (5 μM) or RICO (5 μM) for 48 hrs prior to addition of ERI, the sensitivity to ERI was significantly enhanced. The enhancement of sensitivity to ERI both by the simultaneous addition with low concentration of VOR or RICO and by the prior treatment with VOR or RICO was observed in the ERI-resistant cells as well. Moreover, inhibition of HDAC6 by small interfering RNA partially enhanced the sensitivity to ERI in the both parental cell lines. Our study demonstrated the possibility that the combination of ERI with HDAC inhibitor might enhance the antitumor effect of ERI and overcome ERI resistance through acetylation of α-tubulin by HDAC6 inhibition in TNBC cells. Citation Format: Takaaki Oba, Hiroto Izumi, Ken-ichi Ito. Preclinical analysis of synergistic antitumor effect of eribulin and HDAC inhibitor for triple-negative breast cancer cells [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 2924.

Patients with non-small cell lung cancer harboring mutations in the epidermal growth factor receptor gene, including delE746-A750 and L858R, are highly sensitive to therapy with epidermal growth factor receptor-targeting drugs, such as gefitinib and erlotinib, in comparison with those harboring wild-type epidermal growth factor receptor. It remains unclear how such epidermal growth factor receptor mutations are induced. In this study, we examined whether 8-hydroxy-2'-deoxyguanosine, a representative oxygen nucleotide of DNA, could play a role in activating mutations of the epidermal growth factor receptor gene and also whether Y-box binding protein-1 and 8-oxoguanine DNA glycosylase that are involved in repair of oxidative stimuli-induced DNA damages could play any role in epidermal growth factor receptor activating mutations. Immunohistochemistry was used to evaluate the expression of 8-hydroxy-2'-deoxyguanosine, Y-box binding protein-1, and 8-oxoguanine DNA glycosylase in patients with non-small cell lung cancer (N = 170). We analyzed mutations of delE746-A750 and L858R in the epidermal growth factor receptor gene using peptide nucleic acid-locked nucleic acid polymerase chain reaction clamping. In non-small cell lung cancer patients, nuclear 8-hydroxy-2'-deoxyguanosine expression was strongly associated with these epidermal growth factor receptor mutations. Furthermore, nuclear expression of Y-box binding protein-1 was inversely associated with epidermal growth factor receptor mutations; but nuclear expression of 8-oxoguanine DNA glycosylase was not. Among 51 patients who were treated with gefitinib, progression-free survival was substantially better when 8-hydroxy-2'-deoxyguanosine expression was positive, when epidermal growth factor receptor mutations were present, and when nuclear Y-box binding protein-1 expression was negative. Thus, activating mutations of the epidermal growth factor receptor gene in non-small cell lung cancer were closely associated with a decrease in the damage repair process for 8-hydroxy-2'-deoxyguanosine in oxidized DNA.

Histone acetyltransferase (HAT) regulates transcription. We have previously shown that two HAT genes, Clock and Tip60, are overexpressed, and upregulate glutathione biosynthesis and the expression of DNA repair genes in cisplatin-resistant cells. To better understand the mechanism of HAT-related drug resistance, we investigated the role of another HAT gene, p300/CBP-associated factor (PCAF), and found that PCAF was also overexpressed in cisplatin-resistant cells and endowed an antiapoptotic phenotype through enhanced E2F1 expression. PCAF-overexpressing cells showed enhanced expression of E2F1 and conferred cell resistance to chemotherapeutic agents. Downregulation of PCAF decreased E2F1 expression and sensitized cells to chemotherapeutic agents. Moreover, knockdown of PCAF induced G1 arrest and apoptosis. These results suggest that PCAF is one of pleiotropic factors for drug resistance and seems to be critical for cancer cell growth. Mol Cancer Res; 8(6); 864–72. ©2010 AACR.

We have recently reported that N-myc downstream-regulated gene 1 (NDRG1)/Ca(2+)-associated protein with a molecular mass of 43kDa (Cap43) suppresses angiogenesis and tumor growth of pancreatic cancer through marked decreases in both the expression of CXC chemokines and phosphorylation of a NF-kappaB signaling molecule, inhibitor of kappaB kinase (IkappaBalpha). NDRG1/Cap43 is phosphorylated at serine/threonine sites in its C-terminal domain by serum- and glucocorticoid-regulated kinase 1 (SGK1). In this study, we attempted to clarify the domain or site of NDRG1/Cap43 responsible for its suppression of CXC chemokine expression in pancreatic cancer cells. Expression of the deletion constructs CapDelta2 [deletion of amino acids (AA) 130-142] and CapDelta4 [deletion of AA 180-294] as well as the wild-type full sequence of NDRG1/Cap43 (F-Cap), suppressed the production of CXC chemokines such as Groalpha/CXCL1 and ENA-78/CXCL5, whereas no or low suppression was observed in cell expressing the CapDelta5 mutant [deletion of AA 326-350] and CapDelta6 mutant [deletion of AA 326-394]. We further introduced mutations at the serine and threonine sites at 328 [T328A], 330 [S330A] and 346 [T346A], which are susceptible to phosphorylation by SGK1, and also constructed double mutants [T328A, S330A], [T328A, T346A] and [S330A, T346A]. Expression of all these mutants, with the exception of [S330A, T346A], suppressed the production of CXC chemokine to similar levels as their wild-type counterpart. IkappaBalpha was found to be specifically phosphorylated by this double mutant [S330A, T346A] and the CapDelta5 mutant at levels comparable to that induced in their wild-type counterpart. Phosphorylation of NDRG1/Cap43 at both serine330 and threonine346 is required for its suppressive action on the NF-kappaB signaling pathway and CXC chemokine expression in pancreatic cancer cells.

Y-box binding protein-1 (YB-1) plays pivotal roles in acquisition of global drug resistance and cell growth promotion through transcriptional activation of genes for both drug resistance and growth factor receptors. In this study, we investigated whether YB-1 is involved in regulation of the cell cycle and cell proliferation of human cancer cells. Treatment with YB-1 siRNA caused a marked suppression of cell proliferation and expression of a cell cycle related gene, CDC6 by cancer cells. Of cell cycle of cancer cells, S phase content was specifically reduced by knockdown of YB-1. The overexpression of CDC6 abrogated this inhibition of both cell proliferation and S phase entry. ChIP assay demonstrated that YB-1 binds to a Y-box located in the promoter region of the CDC6 gene. Expression of cyclin D1, CDK1 and CDK2 was also reduced with increased expression of p21(Cip1) and p16(INK4A) when treated with YB-1 siRNA. Furthermore, the nuclear YB-1 expression was significantly associated with the level of CDC6 nuclear expression in patients with breast cancer. In conclusion, YB-1 plays an important role in cell cycle progression at G1/S of human cancer cells. YB-1 thus could be a potent biomarker for tumour growth and cell cycle in its close association with CDC6.

Mitochondrial transcription factor A (mtTFA) is necessary for both transcription and maintenance of mitochondrial DNA. This study was conducted to elucidate the clinicopathologic and prognostic significance of mtTFA in patients with endometrial carcinoma. This study investigated the relationship between the immunohistochemical expression of mtTFA and various clinicopathological variables in 276 endometrial carcinomas, including 245 endometrioid adenocarcinomas and 31 nonendometrioid carcinomas (21 serous carcinomas and 10 clear cell adenocarcinomas). Both uni- and multivariate regression analyses were performed. The mtTFA labeling index of endometrioid adenocarcinomas ranged from 0% to 98%, with a median value of 32%, which was selected as the cut-off point for mtTFA expression. The mtTFA expression in endometrioid adenocarcinomas was significantly associated with the surgical stage, myometrial invasion, lymphovascular space invasion, cervical invasion, and lymph node metastasis. In contrast, no correlation between clinicopathologic variables and mtTFA expression was found in nonendometrioid carcinomas. Correlation analysis between mtTFA and p53 expression by using the Pearson test showed significant correlation in endometrioid adenocarcinomas (P = 0.007), but no significant correlation in nonendometrioid carcinomas (P = 0.947). A univariate survival analysis showed that the 10-year overall survival rate of the patients with mtTFA-positive endometrioid adenocarcinoma was significantly worse than that of patients with mtTFA-negative endometrioid adenocarcinoma (80.8% vs. 93.8%, P = 0.012). However, the multivariate analysis revealed that mtTFA expression in endometrioid adenocarcinomas was no independent prognostic factor. The positive mtTFA expression is a useful maker for progression of the tumors and the poor prognosis of the patients in endometrioid adenocarcinomas.

Mina53, whose expression is directly induced by c-Myc, is overexpressed in various cancers and plays an important role in cell growth. To clarify the involvement of Mina53 in lung cancers, we investigated its expression in human lung cancer tissues as well as in various lung cancer cell lines. Mina53 expression was determined by real-time RT-PCR, western blotting, and immunohistochemistry using lung cancer cell lines, normal human bronchial epithelial cells, and lung cancer tissues. Biological effects of Mina53 were evaluated by soft agar colony formation assay and tumorigenicity in nude mice using Mina53-transfected NIH/3T3 cells. cDNA microarray analysis was performed to determine the gene alteration by Mina53 and confirmation was made using real-time RT-PCR with mina53 expression plasmid or mina53 shRNA-transfected NIH/3T3 cells. We observed that 62% of patients evidenced overexpression of Mina53 from the early clinical stages of lung cancer. Differences according to gender, smoking status, or histologic type were not statistically significant. Forced expression of Mina53 in NIH/3T3 cells induced cell transformation, and mina53-transfected NIH/3T3 clones produced tumors in nude mice, demonstrating that Mina53 has oncogenic potential. cDNA microarray revealed that 254 genes had altered expression in a mina53-transfected NIH/3T3 clone. Mina53 regulates several genes related to cell adhesion and metabolism, which have also been reported to be regulated by c-Myc. Genes regulated by Mina53, but not by c-Myc included cytokine/growth factor related genes such as EGFR, IL-6, and HGF. Our results suggest that Mina53 plays an important role in carcinogenesis and may be a target for cancer prevention.

YB-1 controls gene expression through both transcriptional and translational mechanisms and is involved in various biological activities such as brain development, chemoresistance, and tumor progression. We have previously shown that YB-1 is overexpressed in cisplatin-resistant cells and is involved in resistance against DNA-damaging agents. Structural analysis of the YB-1 promoter reveals that several E-boxes may participate in the regulation of YB-1 expression. Here, we show that the E-box–binding transcription factor Twist is overexpressed in cisplatin-resistant cells and that YB-1 is a target gene of Twist. Silencing of either Twist or YB-1 expression induces G1 phase cell cycle arrest of tumor cell growth. Significantly, reexpression of YB-1 led to increase colony formation when Twist expression was down-regulated by small interfering RNA. However, cotransfection of Twist expression plasmid could not increase colony formation when YB-1 expression was down-regulated. Collectively, these data suggest that YB-1 is a major downstream target of Twist. Both YB-1 and Twist expression could induce tumor progression, promoting cell growth and driving oncogenesis in various cancers. Thus, both YB-1 and Twist may represent promising molecular targets for cancer therapy. [Cancer Res 2008;68(1):98–105]

Ras is a key regulator of the MAP kinase-signaling cascade and may cause morphologic change of Ras-transformed cells. Signal transducer and activator of transcription 3 (Stat3) can be activated by cytokine stimulation. In this study, we unravel that Ha- ras V12 overexpression can downregulate the expression of Stat3 protein at a posttranslational level in NIH3T3 cells. Furthermore, we demonstrate that Stat3 expression downregulated by Ha- ras V12 overexpression is through proteosome degradation and not through a mTOR/p70S6K-related signaling pathway. The suppression of Stat3 accompanied by the morphologic change induced by Ha- ras V12 was through mitogen extracellular kinase (MEK)/extracellular-regulated kinase (ERK) signaling pathway. Microtubule disruption is involved in Ha- ras V12 -induced morphologic change, which could be reversed by overexpression of Stat3. Taken together, we are the first to demonstrate that Stat3 protein plays a critical role in Ha- ras V12 -induced morphologic change. Oncogenic Ras-triggered morphologic change is through the activation of MEK/ERK to posttranslationally downregulate Stat3 expression. Our finding may shed light on developing novel therapeutic strategies against Ras-related tumorigenesis.

The focus of the present study was whether and how infiltrating macrophages play a role in angiogenesis and the growth of cancer cells in response to the inflammatory cytokine interleukin (IL)-1β. Lewis lung carcinoma cells overexpressing IL-1β grew faster and induced greater neovascularization than a low IL-1β-expressing counterpart in vivo. When macrophages were depleted using clodronate liposomes, both neovascularization and tumor growth were reduced in the IL-1β-expressing tumors. Co-cultivation of IL-1β-expressing cancer cells with macrophages synergistically augmented neovascularization and the migration of vascular endothelial cells. In these co-cultures, production of the angiogenic factors vascular endothelial growth factor-A and IL-8, monocyte chemoattractant protein-1, and matrix metalloproteinase-9 were increased markedly. The production of these factors, induced by IL-1β-stimulated lung cancer cells, was blocked by a nuclear factor (NF)-κB inhibitor, and also by the knockdown of p65 (NF-κB) and c-Jun using small interference RNA, suggesting involvement of the transcription factors NF-κB and AP-1. These results demonstrated that macrophages recruited into tumors by monocyte chemoattractant protein-1 and other chemokines could play a critical role in promoting tumor growth and angiogenesis, through interactions with cancer cells mediated by inflammatory stimuli. (Cancer Sci 2007; 98: 2009–2018)

Modification of transcription factors by anticancer agents plays an important role in both apoptotic and survival signaling. Here we report that both DNA topoisomerase I and II inhibitors such as SN-38 and etoposide, but not cisplatin, 5-fluorouracil or actinomycin D, can induce phosphorylation of the transcription factor Sp1. Furthermore, DNA topoisomerase inhibitors were shown to transactivate GC-box-dependent promoters such as the SV40 and vascular endothelial growth factor promoters. The phosphorylated form of Sp1 was detectable within 30 min of etoposide treatment and was greatly diminished by the presence of the PI3K inhibitor wortmannin and by DNA-dependent protein kinase (DNA-PK) knockdown. We also confirmed that the phosphorylated form of DNA-PK was increased by treatment with both etoposide and SN-38. Taken together, these findings demonstrate a novel genomic response to anticancer agents that induce Sp1 phosphorylation, and might contribute to tumor progression and drug resistance.

Zinc-finger protein 143 (ZNF143) is a human homolog of Xenopus transcriptional activator staf that is involved in selenocystyl tRNA transcription. We previously showed that ZNF143 expression is induced by treatment with DNA-damaging agents and that it preferentially binds to cisplatin-modified DNA. In this study, the potential function of ZNF143 was investigated. ZNF143 was overexpressed in cisplatin-resistant cells. ZNF143 knockdown in prostate cancer caused increased sensitivity for cisplatin, but not for oxaliplatin, etoposide and vincristine. We also showed that ZNF143 is associated with tumor suppressor gene product p73 but not with p53. p73 could stimulate the binding of ZNF143 to both ZNF143 binding site and cisplatin-modified DNA, and modulate the function of ZNF143. We provide a direct evidence that both Rad51 and flap endonuclease-1 are target genes of ZNF143 and overexpressed in cisplatin-resistant cells. Taken together, these experiments demonstrate that an interplay of ZNF143, p73 and ZNF143 target genes is involved in DNA repair gene expression and cisplatin resistance.

Y-box-binding protein 1 (YB-1), which is a member of the DNA-binding protein family containing a cold-shock domain, has pleiotropic functions in response to various environmental stimuli. As we previously showed that YB-1 is a global marker of multidrug resistance in ovarian cancer and other tumor types. To identify YB-1-regulated genes in ovarian cancers, we investigated the expression profile of YB-1 small-interfering RNA (siRNA)-transfected ovarian cancer cells using a high-density oligonucleotide array. YB-1 knockdown by siRNA upregulated 344 genes, including MDR1, thymidylate synthetase, S100 calcium binding protein and cyclin B, and downregulated 534 genes, including CXCR4, N-myc downstream regulated gene 1, E-cadherin and phospholipase C. Exogenous serum addition stimulated YB-1 translocation from the cytoplasm to the nucleus, and treatment with Akt inhibitors as well as Akt siRNA and integrin-linked kinase (ILK) siRNA specifically blocked YB-1 nuclear localization. Inhibition of Akt activation downregulated CXCR4 and upregulated MDR1 (ABCB1) gene expression. Administration of Akt inhibitor resulted in decrease in nuclear YB-1-positive cancer cells in a xenograft animal model. Akt activation thus regulates the nuclear translocation of YB-1, affecting the expression of drug-resistance genes and other genes associated with the malignant characteristics in ovarian cancer cells. Therefore, the Akt pathway could be a novel target of disrupting the nuclear translocation of YB-1 that has important implications for further development of therapeutic strategy against ovarian cancers.

Y-box-binding proteins are members of the human cold-shock domain protein superfamily, which includes dbpA, dbpB/YB-1, and dbpC/contrin. dbpC/contrin is a germ cell-specific Y-box-binding protein and is suggested to function as a nuclear transcription factor and RNA-binding protein in the cytoplasm. Whereas ubiquitous dbpB/YB-1 expression has been well studied in various types of human carcinomas as a prognostic or predictive marker, the dbpC/contrin expression in human tumour cells has not been reported. In this report, we provide the first evidence showing that dbpC was highly expressed in human testicular seminoma and ovarian dysgerminomas, and in carcinomas in other tissues and that its expression in normal tissues is nearly restricted to germ cells and placental trophoblasts. These results indicate that dbpC/contrin would be a potentially novel cancer/testis antigen.

Background The Y-box binding protein 1 (YB-1) possesses pleiotropic functions through its interactions with various cellular proteins, and its high expression levels make it a potential useful prognostic biomarker for cancer cells. Eukaryotic DNA topoisomerases, such as DNA topoisomerase 1 (TOPO1) and DNA topoisomerase 2 (TOPO2), are the essential DNA metabolism regulators that usually overexpressed in cancer cells, and multiple proteins have been reported to regulate the enzyme activity and the clinical efficacy of their inhibitors. The present study unraveled the interaction of YB-1 with TOPO1, and further investigated the related function and potential mechanisms during the interaction. Methods The direct association of TOPO1 with specific domain of YB-1 was explored by co-immunoprecipitation and GST pull-down assays. The interaction function was further clarified by DNA relaxation assays, co-immunoprecipitation and WST-8 assays with in vitro gain- and loss- of function models. Results We found that YB-1 interacts directly with TOPO1 (but not with TOPO2) and promotes TOPO1 catalytic activity. Interactions between YB-1 and TOPO1 increased when cancer cells were treated with the TOPO1 inhibitor, camptothecin (CPT), but not with the TOPO2 inhibitor, adriamycin (ADM). Furthermore, we found that the interaction is prevented by pretreatment with the antioxidant agent, N-acetyl cysteine, and that YB-1 downregulation renders cells resistant to CPT. Conclusions Our findings suggest that nuclear YB-1 serves as an intracellular promoter of TOPO1 catalytic activity that enhances CPT sensitivity through its direct interaction with TOPO1.

Purpose: The Y-box binding protein 1 (YB-1) regulates expression of P-glycoprotein encoded by the MDR1 gene. There have been no previous studies regarding the involvement of YB-1 in the development of resistance to paclitaxel. The present study was done to examine how paclitaxel affects the localization and expression of YB-1 in breast cancer. Experimental Design: We evaluated the expression and localization of YB-1 and P-glycoprotein in breast cancer tissues obtained from 27 patients before and after treatment with paclitaxel. The effect of paclitaxel on localization of cellular YB-1 was examined by using GFP-YB-1. Interaction of YB-1 with the Y-box motif of the MDR1 promoters was studied by electrophoretic mobility shift assay. The effects of paclitaxel on MDR1 promoter activity were examined by luciferase assay. Results: Of 27 breast cancer tissues treated with paclitaxel, nine (33%) showed translocation of YB-1 from the cytoplasm to the nucleus together with increased expression of P-glycoprotein during the course of treatment. Twelve breast cancer tissues (44%) showed neither translocation of YB-1 nor increased expression of P-glycoprotein. Nuclear translocation of YB-1 was correlated significantly with increased expression of P-glycoprotein (P = 0.0037). Confocal analysis indicated that paclitaxel induced nuclear translocation of green fluorescent fused YB-1 in MCF7 cells. Furthermore, binding of YB-1 to the Y-box of MDR1 promoter was increased in response to treatment with paclitaxel. In addition, MDR1 promoter activity was significantly up-regulated by paclitaxel in MCF7 cells (P < 0.001). Conclusions: The results of the present study suggested that YB-1 may be involved in the development of resistance to paclitaxel in breast cancer.

Cisplatin is one of the most potent and widely used anti-cancer agents in the treatment of various solid tumors. However, the development of resistance to cisplatin is a major obstacle in clinical treatment. Several mechanisms are thought to be involved in cisplatin resistance, including decreased intracellular drug accumulation, increased levels of cellular thiols, increased nucleotide excision-repair activity and decreased mismatch-repair activity. In general, the molecules responsible for each mechanism are upregulated in cisplatin-resistant cells; this indicates that the transcription factors activated in response to cisplatin might play crucial roles in drug resistance. It is known that the tumor-suppressor proteins p53 and p73, and the oncoprotein c-Myc, which function as transcription factors, influence cellular sensitivity to cisplatin. So far, we have identified several transcription factors involved in cisplatin resistance, including Y-box binding protein-1 (YB-1), CCAAT-binding transcription factor 2 (CTF2), activating transcription factor 4 (ATF4), zinc-finger factor 143 (ZNF143) and mitochondrial transcription factor A (mtTFA). Two of these-YB-1 and ZNF143-lack the high-mobility group (HMG) domain and can bind preferentially to cisplatin-modified DNA in addition to HMG domain proteins or DNA repair proteins, indicating that these transcription factors may also participate in DNA repair. In this review, we summarize the mechanisms of cisplatin resistance and focus on transcription factors involved in the genomic response to cisplatin.

The C-terminus of p53 is responsible for maintaining the latent, non-DNA-binding form of p53. However, the mechanism by which the C-terminus regulates DNA binding is not yet fully understood. We show here that p53 interacts with RNA via its C-terminal domain and that disruption of this interaction, by RNase A treatment, truncation or phosphorylation of the C-terminus, restores DNA-binding activity. Furthermore, the oligomerization of p53 is significantly enhanced by disrupting the interaction between p53 and RNA. These findings suggest that binding of RNA to p53 is involved in the mechanism of p53 latency.

Initial glycosylation of mucin-type O-linked protein is catalysed by one of the UDP-GalNAc: polypeptide N-acetyl-galactosaminyl transferase-3 (GalNAc-T3). O-glycosylation is important in the binding of cell adhesion molecules, cell differentiation, invasion, and metastasis in tumours. This study was designed to detect GalNAc-T3 expression in lung adenocarcinoma by using immunohistochemical staining, and to evaluate the relationship between the GalNAc-T3 expression level and prognosis and recurrence in completely resected lung adenocarcinoma patients. A low expression of GalNAc-T3 was detected in the cytoplasm of tumour cells in 79 of 148 patients (53.4%) with lung adenocarcinoma. The low expression of GalNAc-T3 was associated with poorly differentiated tumour (P

We have identified a cisplatin-inducible gene, the mitochondrial ribosomal protein S11 (MRP S11) gene, by means of mRNA differential display. Functional analysis of the MRP S11 promoter showed that a Staf binding site in the promoter is required for both basal promoter activity and cisplatin-inducible activity. We also found that Staf binding activity is significantly increased in nuclear extracts from cells treated with cisplatin. ZNF 143 and ZNF 76 are human homologues of the Xenopus transcriptional activator, Staf. ZNF 143 expression is induced by cisplatin but ZNF 76 expression is not. However, ZNF 143 expression is not induced by transplatin, which is clinically ineffective. ZNF143 is an inducible gene by other DNA damaging agents such as γ-irradiation, etoposide and adriamycin. ZNF 143 also binds preferentially to cisplatin-modified DNA. These results suggest that ZNF 143 participates in cellular responses to DNA damage. © 2004 Wiley-Liss, Inc.