Phase II study of brigatinib in patients with ROS1 fusion-positive non-small-cell lung cancer: the Barossa study.

BACKGROUND: Brigatinib is a next-generation tyrosine kinase inhibitor (TKI) targeting ALK and ROS1. The Barossa study is a multicenter, phase II basket study of brigatinib in patients with ROS1-rearranged solid tumors. ROS1 TKI-naive patients with ROS1-rearranged non-small-cell lung cancer (NSCLC) were enrolled in cohort 1, and ROS1-rearranged NSCLC patients treated previously with crizotinib were enrolled in cohort 2. Patients with ROS1-rearranged solid tumors other than NSCLC were enrolled in cohort 3. PATIENTS AND METHODS: Eligible patients received brigatinib at the dose of 180 mg once daily with a 7-day lead-in period at 90 mg. The primary endpoint was the objective response rate (RECIST 1.1) assessed by independent central review in cohorts 1 and 2. RESULTS: Between July 2019 and June 2021, 51 patients were enrolled into the study. Of the 51, 47 patients had ROS1-rearranged NSCLC; 28 and 19 of these patients were enrolled in cohort 1 and cohort 2, respectively. The remaining four patients had other ROS1-rearranged solid tumors, including rectal, brain, and pancreas tumor in one patient each, and primary unknown tumor in one patient. The confirmed objective response rate was 71.4% [95% confidence interval (CI) 51.3% to 86.8%] in cohort 1 (TKI-naive NSCLC patients) and 31.6% (95% CI 12.6% to 56.6%) in cohort 2 (NSCLC patients treated previously with crizotinib). The median progression-free survival was 12.0 months (95% CI 5.5-22.9 months) in cohort 1 and 7.3 months (95% CI 1.3-17.5 months) in cohort 2. None of the patients in cohort 3 showed any treatment response. Pneumonitis was observed in 9.8% of all the patients. CONCLUSIONS: Brigatinib was effective in TKI-naive patients with ROS1-rearranged NSCLC. The safety profile of brigatinib was consistent with that reported from previous studies.

Aberrant expression of microRNAs and the miR-1/MET pathway in canine hepatocellular carcinoma.

Canine hepatocellular carcinoma (HCC) is the most common primary hepatic tumour in dogs. MicroRNA (miRNA) dysregulation has been reported in human HCC and shown to have diagnostic and prognostic value; however, there are no data on miRNA expression in canine HCC. The aim of the present study was to investigate differentially expressed miRNAs in canine HCC. Analysis of miRNA expression in canine HCC tissues and cell lines by quantitative reverse transcription PCR showed that miR-1, miR-122, let-7a, and let-7g were downregulated, whereas miR-10b and miR-21 were upregulated in canine HCC. MET is one of the target genes of miR-1. MET was upregulated in canine HCC at the gene and protein levels, and a significant correlation between the concomitant downregulation of miR-1 and upregulation of MET was observed. Fast/intermediate-proliferating canine HCC cell lines had higher MET gene and protein expression levels than the slow-proliferating cell line. These findings suggest that miRNAs are differentially expressed in canine HCC, and that the miR-1/MET pathway may be associated with canine HCC cell proliferation.

Bifidobacterium breve prevents necrotising enterocolitis by suppressing inflammatory responses in a preterm rat model.

Necrotising enterocolitis (NEC) is associated with inflammatory responses and barrier dysfunction in the gut. In this study, we investigated the effect of Bifidobacterium breve M-16V on factors related to NEC development using an experimental rat model. Caesarean-sectioned rats were given formula milk with or without B. breve M-16V by oral gavage thrice daily, and experimental NEC was induced by exposing the rats to hypoxic conditions. Naturally delivered rats that were reared by their mother were used as healthy controls. The pathological score of NEC and the expression of molecules related to inflammatory responses and the barrier function were assessed in the ileum. B. breve M-16V reduced the pathological scores of NEC and resulted in some improvement in survivability. B. breve M-16V suppressed the increased expression of molecules related to inflammation and barrier function that resulted from NEC induction. B. breve M-16V normalised Toll-like receptor (TRL)4 expression and enhanced TLR2 expression. Our data suggest that B. breve M-16V prevents NEC development by modulating TLR expressions and suppressing inflammatory responses in a rat model.

Fabrication of electron beam deposited tip for atomic-scale atomic force microscopy in liquid.

Recently, possibilities of improving operation speed and force sensitivity in atomic-scale atomic force microscopy (AFM) in liquid using a small cantilever with an electron beam deposited (EBD) tip have been intensively explored. However, the structure and properties of an EBD tip suitable for such an application have not been well-understood and hence its fabrication process has not been established. In this study, we perform atomic-scale AFM measurements with a small cantilever and clarify two major problems: contaminations from a cantilever and tip surface, and insufficient mechanical strength of an EBD tip having a high aspect ratio. To solve these problems, here we propose a fabrication process of an EBD tip, where we attach a 2 µm silica bead at the cantilever end and fabricate a 500-700 nm EBD tip on the bead. The bead height ensures sufficient cantilever-sample distance and enables to suppress long-range interaction between them even with a short EBD tip having high mechanical strength. After the tip fabrication, we coat the whole cantilever and tip surface with Si (30 nm) to prevent the generation of contamination. We perform atomic-scale AFM imaging and hydration force measurements at a mica-water interface using the fabricated tip and demonstrate its applicability to such an atomic-scale application. With a repeated use of the proposed process, we can reuse a small cantilever for atomic-scale measurements for several times. Therefore, the proposed method solves the two major problems and enables the practical use of a small cantilever in atomic-scale studies on various solid-liquid interfacial phenomena.

Y-box binding protein 1 expression in gastric cancer subtypes and association with cancer neovasculature

Purpose. Y-box binding protein 1 (YB-1) expression in cancer cells is closely associated with malignant progression and poor prognosis in various cancers. Recently, we demonstrated that YB-1 expression in cancer cells is an immunomarker for patient prognosis and liver metastasis of gastric cancer (GC), and identified YB-1 as an excellent biomarker of angiogenic and proliferating endothelial cells in cancers. We further explored the expression patterns of YB-1 in gastric vasculature and the relationship with the clinical pathologic characteristics, as well as YB-1 phenotype in cancer cells. Methods/Patients. Immunohistochemical analysis of YB-1 was performed using 163 surgically resected primary GC specimens. Results. YB-1 expression in cancer cells significantly differed with respect to Lauren type, JGCA classification, vascular invasion (VI), and microvessel density (MVD) of cancers (P = 0.018, P = 0.002, P < 0.001, and P < 0.001, respectively). No correlation was found between cancer-cell YB-1 expression and TNM stage or lymphatic invasion. However, YB-1 expression in vascular endothelial cells significantly correlated with N stage, M stage, TNM stage, and MVD of cancers (P < 0.001, P = 0.013, P < 0.001, and P < 0.001, respectively). Notably, cases with YB-1 expression in cancer vasculature also demonstrated YB-1 expression in cancer cells (P = 0.040). Conclusions. YB-1 may promote GC development through its function in both cancer cells and cancer vascular cells, and thus represent a potential biomarker in this disease (AU)

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Y-box binding protein 1 expression in gastric cancer subtypes and association with cancer neovasculature.

PURPOSE: Y-box binding protein 1 (YB-1) expression in cancer cells is closely associated with malignant progression and poor prognosis in various cancers. Recently, we demonstrated that YB-1 expression in cancer cells is an immunomarker for patient prognosis and liver metastasis of gastric cancer (GC), and identified YB-1 as an excellent biomarker of angiogenic and proliferating endothelial cells in cancers. We further explored the expression patterns of YB-1 in gastric vasculature and the relationship with the clinical pathologic characteristics, as well as YB-1 phenotype in cancer cells. METHODS/PATIENTS: Immunohistochemical analysis of YB-1 was performed using 163 surgically resected primary GC specimens. RESULTS: YB-1 expression in cancer cells significantly differed with respect to Lauren type, JGCA classification, vascular invasion (VI), and microvessel density (MVD) of cancers (P = 0.018, P = 0.002, P < 0.001, and P < 0.001, respectively). No correlation was found between cancer-cell YB-1 expression and TNM stage or lymphatic invasion. However, YB-1 expression in vascular endothelial cells significantly correlated with N stage, M stage, TNM stage, and MVD of cancers (P < 0.001, P = 0.013, P < 0.001, and P < 0.001, respectively). Notably, cases with YB-1 expression in cancer vasculature also demonstrated YB-1 expression in cancer cells (P = 0.040). CONCLUSIONS: YB-1 may promote GC development through its function in both cancer cells and cancer vascular cells, and thus represent a potential biomarker in this disease.

The combination of strong expression of ZNF143 and high MIB-1 labelling index independently predicts shorter disease-specific survival in lung adenocarcinoma.

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.

Polypeptide N-acetylgalactosaminyl transferase 3 independently predicts high-grade tumours and poor prognosis in patients with renal cell carcinomas.

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 ß-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.

Bovine milk contains microRNA and messenger RNA that are stable under degradative conditions.

We previously reported that microRNA (miRNA) is present in human breast milk. Recently, other groups have reported that bovine milk also contains miRNA; however, these reports are few. We therefore investigated bovine milk miRNA using microarray and quantitative PCR analyses to identify the differences between colostrum and mature milk. The RNA concentration in a colostrum whey fraction was higher than that in a mature milk whey fraction. In total, 102 miRNA were detected in bovine milk by microarray analysis (100 in colostrum and 53 in mature milk; 51 were common to both). Among these miRNA, we selected several immune- and development-related miRNA, including miR-15b, miR-27b, miR-34a, miR-106b, miR-130a, miR-155, and miR-223. These miRNA were detected in bovine milk by quantitative PCR, and each of these miRNA was significantly more highly expressed in colostrum than in mature milk. We also confirmed the presence of some mRNA in bovine milk. Nevertheless, synthesized miRNA spiked in the raw milk whey were degraded, and naturally existing miRNA and mRNA in raw milk were resistant to acidic conditions and RNase treatment. The RNA molecules in milk were stable. We also detected miRNA and mRNA in infant formulas purchased from Japanese markets. It is still unknown whether milk-derived RNA molecules play biological roles in infants; however, if milk-derived RNA do show functions in infants, our data will help guide future studies.

Prognostic significance of BAF57 expression in patients with endometrial carcinoma.

This study was conducted to elucidate the prognostic significance of BAF57 in patients with endometrial carcinoma. We investigated the relationship between the immunohistochemical expression of BAF57 and various clinicopathological variables in 111 endometrial carcinomas. Both univariate and multivariate regression analyses were performed. The correlations between the BAF57 expression and the other variables including estrogen receptor (ER) and p53 were examined. The high nuclear BAF57 expression was detected in 42 (37.8%) endometrial carcinomas, and 69 (62.2%) endometrial carcinomas were defined as having low nuclear BAF57 expression. The BAF57 expression was significantly associated with the surgical stage, grade of the tumor, myometrial invasion, lympho-vascular space invasion (LVSI) and lymph node metastasis. The 10-year overall survival rates of patients with low and high BAF57 expression were 96.9% and 58.2%, respectively (p<0.001). A multivariate analysis identified BAF57 expression as an independent prognostic factor. The BAF57 expression was significantly correlated with p53 expression (r=0.312, P=0.001), but was not correlated with ER expression (r= -0.141, P=0.14). The high BAF57 expression is an independent marker of poor prognosis of the patients in endometrial carcinomas. The inhibition of BAF57 activity may be one of the candidates for endometrial cancer therapy, especially therapy for aggressive tumors showing overexpression of p53.

Polypeptide N-acetylgalactosaminyltransferase 6 expression in pancreatic cancer is an independent prognostic factor indicating better overall survival.

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.

[Direct instillation of the fibrin glue into the ruptured bulla is an effective treatment for uncontrolled pneumothorax occurred from severe emphysematous bullae].

From May 2005 to October 2010. 9 patients with severe emphysematous bullae suffered from uncontrolled pneumothorax had been successfully treated by a new surgical method in our hospital. By using direct instillation of fibrin glue into the ruptured bulla following ligation of the ruptured bulla hole, 8 of 9 patients revealed no recurrence of new rupture and pneumothorax. Although the ligation of ruptured bulla hole tended to increase tension of surface of the bulla around the ligation and caused new rupture of the bulla, the fully instilled glue reduced intra air pressure of the ligated bulla and prevented new rupture. Additionally, the direct instillation of the glue immediately stopped the air leakage by itself. This direct instillation method of the glue encouraged us to challenge the surgery for the patients suffered from uncontrolled pneumothorax with severe emphysematous bullae.

BubR1 localizes to centrosomes and suppresses centrosome amplification via regulating Plk1 activity in interphase cells.

BubR1 is a critical component of the mitotic checkpoint that delays the onset of anaphase until all chromosomes have established bipolar attachment to the microtubules. We previously reported that mutations of the BUB1B gene (encoding BubR1) caused premature chromatid separation (PCS) syndrome, a condition characterized by constitutional aneuploidy and a high risk of childhood cancer. We here report that the cells from PCS syndrome patients have loss of regulation of the centrosome duplication machinery, resulting in centrosome amplification and multipolar mitosis. PCS syndrome cells show increased activity of Polo-like kinase 1 (Plk1), whose knockdown suppresses centrosome amplification. BubR1 localizes to centrosomes, physically interacts with Plk1 and inhibits Plk1 phosphorylation and its kinase activity during interphase. These results unravel a crucial role of BubR1 in preventing centrosome reduplication through negative regulation of Plk1 in interphase cells.

Isolation of polymorphic microsatellite markers in the tree sparrow (Passer montanus).

To enable the study of the population genetics of the tree sparrow (Passer montanus), which is distributed in many islands of Japan, nine polymorphic microsatellite loci were isolated from 32 individuals. The number of alleles per locus ranged from 2 to 17, and observed heterozygosities ranged from 0.1250 to 0.9375. In eight of the nine loci, the heterozygosities were not significantly different from those expected from Hardy-Weinberg equilibrium. Cross-species amplification in the russet sparrow (P. rutilans) was successful with all primer sets, which were highly polymorphic, suggesting these markers are useful for the population genetics of genus Passer.

Twist and p53 reciprocally regulate target genes via direct interaction.

Twist is basic helix-loop-helix transcription factor that binds to E-boxes in gene promoters. Twist possesses an oncogenic function by interfering with the tumor suppressor function of p53. Using a membrane pull-down assay, we found that Twist directly interacts with p53 and that this interaction underlies the inhibitory effects on p53 target gene expression. Twist interacted with the DNA-binding domain of p53 and suppressed the DNA-binding activity of p53. Transcriptional activation of the p21 promoter by p53 was significantly repressed by the expression of Twist. On the other hand, p53 interacted with the N-terminal domain of Twist and repressed Twist-dependent YB-1 promoter activity. Importantly, we found that p53-dependent growth suppression was canceled by the expression of either Twist or YB-1. Thus, our data suggest that Twist inhibits p53 function via a direct interaction with p53.

Centrosome amplification induced by survivin suppression enhances both chromosome instability and radiosensitivity in glioma cells.

Glioblastoma is characterised by invasive growth and a high degree of radioresistance. Survivin, a regulator of chromosome segregation, is highly expressed and known to induce radioresistance in human gliomas. In this study, we examined the effect of survivin suppression on radiosensitivity in malignant glioma cells, while focusing on centrosome aberration and chromosome instability (CIN). We suppressed survivin by small interfering RNA transfection, and examined the radiosensitivity using a clonogenic assay and a trypan blue exclusion assay in U251MG (p53 mutant) and D54MG (p53 wild type) cells. To assess the CIN status, we determined the number of centrosomes using an immunofluorescence analysis, and the centromeric copy number by fluorescence in situ hybridisation. As a result, the radiosensitisation differed regarding the p53 status as U251MG cells quickly developed extreme centrosome amplification (=CIN) and enhanced the radiosensitivity, while centrosome amplification and radiosensitivity increased more gradually in D54MG cells. TUNEL assay showed that survivin inhibition did not lead to apoptosis after irradiation. This cell death was accompanied by an increased degree of aneuploidy, suggesting mitotic cell death. Therefore, survivin inhibition may be an attractive therapeutic target to overcome the radioresistance while, in addition, proper attention to CIN (centrosome number) is considered important for improving radiosensitivity in human glioma.

Occurrence of parasympathetic vasodilator fibers in the lower lip of the guinea-pig.

The present study was designed to examine whether there are parasympathetic vasodilator fibers in the lower lip of the guinea-pig. Electrical stimulation of the central cut end of the lingual nerve of guinea-pigs evoked intensity- and frequency-dependent decreases in lower lip blood flow and systemic arterial blood pressure (SABP). Pretreatment with guanethidine, a postganglionic sympathetic nerve blocker and antihypertensive drug (30 mg kg(-1), s.c., 24 h prior to experiments), reduced the magnitude of the decrease in SABP while the intensity- and frequency-dependent increases of the lip blood flow occurred by the lingual nerve stimulation only on the side ipsilateral to stimulation. Increases in the lip blood flow evoked by lingual nerve stimulation in guanethidine pretreated guinea-pigs were reduced by hexamethonium (an autonomic ganglion cholinergic blocker) in a dose-dependent manner. When fluoro-gold (a retrograde neural tracer) was injected into the lower lip, labeled neurons were observed in the ipsilateral otic ganglion. The present study indicates the presence of parasympathetic vasodilator fibers originating from the otic parasympathetic ganglion in the guinea-pig lower lip, similar to those reported previously in rats, cats, rabbits and humans.

ZNF143 interacts with p73 and is involved in cisplatin resistance through the transcriptional regulation of DNA repair genes.

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.

Clock and ATF4 transcription system regulates drug resistance in human cancer cell lines.

The mechanisms underlying cellular drug resistance have been extensively studied, but little is known about its regulation. We have previously reported that activating transcription factor 4 (ATF4) is upregulated in cisplatin-resistant cells and plays a role in cisplatin resistance. Here, we find out a novel relationship between the circadian transcription factor Clock and drug resistance. Clock drives the periodical expression of many genes that regulate hormone release, cell division, sleep-awake cycle and tumor growth. We demonstrate that ATF4 is a direct target of Clock, and that Clock is overexpressed in cisplatin-resistant cells. Furthermore, Clock expression significantly correlates with cisplatin sensitivity, and that the downregulation of either Clock or ATF4 confers sensitivity of A549 cells to cisplatin and etoposide. Notably, ATF4-overexpressing cells show multidrug resistance and marked elevation of intracellular glutathione. The microarray study reveals that genes for glutathione metabolism are generally downregulated by the knockdown of ATF4 expression. These results suggest that the Clock and ATF4 transcription system might play an important role in multidrug resistance through glutathione-dependent redox system, and also indicate that physiological potentials of Clock-controlled redox system might be important to better understand the oxidative stress-associated disorders including cancer and systemic chronotherapy.

Akt-dependent nuclear localization of Y-box-binding protein 1 in acquisition of malignant characteristics by human ovarian cancer cells.

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.