Abstract P4-15-08: Discovery of a potent inhibitor of CREB-mediated gene transcription that completely suppresses the growth of triple-negative breast cancer cells

Background: Breast cancers are a heterogeneous group of diseases with distinct and complex mechanisms of pathogenesis. Triple-negative breast cancers (TNBC) form a subgroup of breast cancers with poor prognosis. TNBCs lack the expression of estrogen receptor (ER), progesterone receptor (PR) or HER2 and no targeted therapies exist. The cyclic-AMP (cAMP) response element binding protein (CREB) is a stimulus-induced transcription factor activated by multiple extracellular signals through phosphorylation. The transcription activity of CREB depends on its phosphorylation at Ser133 by mitogen- and stress-activated protein serine/threonine kinases, which are often dysregulated in TNBCs. The phosphorylated CREB (p-CREB) can then bind the mammalian transcription co-activator, CREB-binding protein (CBP), via the kinase-inducible domain (KID) in CREB and KID-interacting (KIX) domain in CBP. This binding event will further recruit other transcriptional machinery to the gene promoter to initiate CREB-dependent gene transcription. CREB is overexpressed in breast cancer tissues compared to normal mammary tissues and the level of expression inversely correlates with disease-free survival. Genetic studies have shown that inhibition of CREB's activity leads to decreased breast cancer cell proliferation. We describe here the discovery of a potent small molecule inhibitor of CREB-mediated gene transcription with in vitro and in vivo activity in TNBCs.

Methods: The small molecule inhibitor (compound 1) was reporter earlier by us (Li and Xiao ChemBioChem 2009). Starting from this lead compound, we designed and synthesized a more potent compound 2. The in vitro antiproliferative activity and apoptosis induction were evaluated in MDA-MB-231 and MDA-MB-468 cells with MTT assays and flow cytometry, respectively. In vivo activity was investigated in a human xenograft model of MDA-MB-468. The CREB target gene expression was investigated by Western blot and qRT-PCR analysis.

Results: Starting from compound 1, which is a low micromolar and cell-permeable inhibitor of CREB-mediated gene transcription, we designed and synthesized compound 2. Compound 2 potently inhibited CREB-mediated gene transcription with IC50 ∼80 nM. In vitro, this compound inhibited proliferation of MDA-MB-231 and MDA-MB-468 cells with concomitant activation of apoptosis and necrosis. In contrast, compound 2 was not toxic to normal human mammary epithelial cells. In vivo, compound 2 completely suppressed the growth of MDA-MB-468 cells at a dose not toxic to the mice.

Conclusion: Compound 2 potently inhibited CREB-mediated gene transcription and TNBC cell growth in vitro and in vivo. These results suggest that CREB is a promising druggable target for TNBCs.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-15-08.

Mycobacterium tuberculosis MPT64 stimulates the activation of murine macrophage modulated by IFN-γ

BACKGROUND AND AIMS

MPT64, a major target of cell-mediated immunity in tuberculosis, is proposed to be a promising candidate for novel vaccines and diagnostic tests; it also involves in virulence mechanism of Mycobacterium tuberculosis. In this study, we investigated the effect of MPT64 on activation of RAW264.7 macrophage, and explored the possible mechanism.

MATERIALS AND METHODS

MPT64 protein was prepared by cloning, expression and purification from Escherichia (E.) coli. Cytokines (IL-1β, IL-6, IL-10 and TNF-α) expression in RAW264.7 macrophage induced by MPT64 was evaluated by xMAP technology. Cell counting kit (CCK8) assay was employed to detect the viability of MPT64-treated macrophage; moreover, flow cytometric analysis and Western Blot analysis were used to measure the effect of MPT64 on apoptosis in macrophage and cleaved caspase-3 expression respectively.

RESULTS

MPT64 significantly promoted the levels of IL-1β, IL-6, IL-10 and TNF-α; pretreatment of MPT64 followed by IFN-γ stimulation further up-regulated IL-6 production (p < 0.01, compared with MPT64-treated group). In CCK8 assay, significantly increased absorbance of MPT64-treated macrophage suggested that cell viability might be enhanced. Additionally, MPT64 modulated the apoptosis of RAW264.7 macrophage partly through caspase-3 pathway.

CONCLUSIONS

MPT64 activated RAW264.7 macrophage to secrete IL-1β, IL-6, IL-10 and TNF-α; it might down-regulate apoptosis of macrophage partially via caspase-3 pathway. Furthermore, the effect of MPT64 on RAW264.7 macrophage could be modulated by IFN-γ, and co-stimulation of MPT64 with IFN-γ was conducive to the host immune, which might be applied for vaccine design and provide a reference for the treatment of tuberculosis.

Epigenetic inactivation of SPINT2 is associated with tumor suppressive function in esophageal squamous cell carcinoma

Hepatocyte growth factor activator inhibitor type 2 (SPINT2), a Kunitz-type serine proteinase inhibitor, has been identified as a putative tumor suppressor gene silenced by promoter methylation. We aimed to investigate whether SPINT2 might act as an esophageal squamous cell carcinoma (ESCC) tumor suppressor gene. Four ESCC cell lines, Fifty-two ESCC tissues and twenty-nine neighboring non-cancerous tissues were included in this study. The expression of SPINT2 was monitored by real time PCR. Bisulfite genomic sequencing and methylation-specific PCR were used to analyze methylation status. The effect of SPINT2 on cell proliferation and apoptosis in EC109 and EC9706 cells was observed by CCK-8 assay and flow cytometric analysis. We found that silencing of SPINT2 was associated with promoter methylation in ESCC cell lines. The densely methylated SPINT2 promoter region was confirmed by bisulfite genomic sequencing. Ectopic expression of SPINT2 inhibited cell proliferation through inducing cell apoptosis in vitro. Furthermore, methylation-specific PCR analysis revealed that SPINT2 promoter methylation was prominent in carcinoma tissues (52.08%) compared with neighboring non-cancerous tissues (22.58%). Kaplan-Meier analysis showed that patients with SPINT2 hypermethylation had shorter survival time. The tumor suppressor gene of SPINT2 is commonly silenced by promoter hypermethylation in human ESCC and SPINT2 hypermethylation is correlated with poor overall survival, implicating SPINT2 is an underlying prognostic marker for human ESCC.

microRNA-27a functions as a tumor suppressor in esophageal squamous cell carcinoma by targeting KRAS

microRNAs (miRNAs) have been suggested to play a vital role in regulating tumor progression and invasion. However, the expression of miR-27a in esophageal squamous cell carcinoma (ESCC) and its effect on the tumorigenesis of ESCC are unclear. In the present study, we found that miR-27a was downregulated in esophageal carcinoma cell lines and ESCC specimens with lymph node metastasis. Furthermore, we demonstrated that miR-27a binds to the 3'-untranslated region (UTR) of KRAS and inhibits the expression of the KRAS protein. miR-27a levels were inversely correlated with levels of KRAS mRNA and protein in ESCC specimens. Both in vitro and in vivo assays revealed that miR-27a attenuated ESCC proliferation, invasion and tumor growth in nude mice. miR-27a exerts its tumor suppressor function through inhibition of the KRAS-related ERK pathways. Our findings suggest, for the first time, that miR-27a suppresses tumorigenesis of ESCC by targeting KRAS.

Clinical and molecular prognostic predictors of malignant peripheral nerve sheath tumor

OBJECTIVE

Malignant peripheral nerve sheath tumors (MPNST) are relatively rare sarcomas and poorly understood. We sought to find clinicopathological and molecular predictors of survival for Chinese MPNST patients.

METHODS

Clinical information from 146 MPNST patients treated in the Tianjin Medical University Cancer Institute and Hospital was collected and 56 cases of formalin-fixed and paraffin-embedded tissues were available for immunohistochemical examination of expression of hepatocyte growth factor receptor (c-MET), E3 ubiquitin-protein ligase Mdm2 (MDM2), and TP53.

RESULTS

The 5-year tumor-free survival rate was 24 % and the median tumor-free survival time was 25.64 months. The 5-year overall survival rate was 57 % and the median overall survival time was 132.57 months. The expression patterns of c-MET, TP53, and MDM2 were heterogeneous with total positivity rates of 82.1 % (46/56), 55.4 % (31/56), and 73.2 % (41/56), respectively. The univariate analysis not only showed that tumor size, Neurofibromin 1 (NF1) status, the American Joint Committee on Cancer (AJCC) stage, surgery, MDM2 expression, and TP53 expression had significant correlation with the tumor-free survival, but also demonstrated that radiotherapy, chemotherapy, tumor size, and NF1 status had significant correlation with the overall survival. Even though multivariate analysis found no independent prognostic predictor of MPNST, tumor size and NF1 status had significant correlation with the tumor-free survival and overall survival of MPNST patients.

CONCLUSIONS

With this, the largest documented Chinese cohort, our data supply powerful Chinese evidence of the prognostic role of tumor size and NF1 status in MPNST.

NF-κBP65 promotes invasion and metastasis of oesophageal squamous cell cancer by regulating matrix metalloproteinase-9 and epithelial-to-mesenchymal transition

NF-κB has been recognized as one of the factors responsible for the development of cancer; however, the mechanism by which high expression of NF-κB contributes to the progression of human oesophageal squamous cell cancer (ESCC) is not fully understood. In our investigations, NF-κBP65 was overexpressed in human ESCC tissues, especially in ESCC tissues with deep invasion and lymph node metastasis. Suppression of NF-κBP65 by siRNA decreased the invasion and proliferation ability of EC9706 cells in vitro. Furthermore, siRNA-mediated NF-κBP65 knock-down could lead to the downregulation of MMP-9, a metastasis-related gene. Reduced E-cadherin is a hallmark of invasive carcinomas that have acquired epithelial-mesenchymal transition (EMT) phenotypes and Vimentin is another molecule that is used widely as a marker of the EMT. We found upregulation of E-cadherin expression and downregulation of Vimentin was induced by NF-κBP65 siRNA, which suggests that NF-κBP65 siRNA could inhibit the invasion and proliferation ability of ECSS through attenuating the expression of MMP-9 and EMT. Thus, ESCC NF-κBP65 could be a useful target for cancer prevention and therapy.

Surface anatomical profile of the cerebral cortex in obsessive-compulsive disorder: a study of cortical thickness, folding and surface area

BACKGROUND

Studying the distribution of anatomical abnormalities over the entire cortical surface can help to identify key neural circuits implicated in generating symptoms of neuropsychiatric disorders. There is a significant inconsistency among studies investigating the neuroanatomy of obsessive-compulsive disorder (OCD) because of the confounding influence of co-morbid depression and medication use and the lack of unbiased estimation of whole-brain morphometric changes. It is also unknown whether the distinct surface anatomical properties of thickness, surface area and gyrification, which collectively contribute to grey matter volume (GMV), are independently affected in OCD. Method The cortical maps of thickness, gyrification and surface areal change were acquired from 23 unmedicated OCD patients and 20 healthy controls using an unbiased whole-brain surface-based morphometric (SBM) method to detect regional changes in OCD. Subcortical structures were not assessed in this study.

RESULTS

Patients showed a significant increase in the right inferior parietal cortical thickness. Significant increases in gyrification were also noted in the left insula, left middle frontal and left lateral occipital regions extending to the precuneus and right supramarginal gyrus in OCD. Areal contraction/expansion maps revealed no significant regional differences between the patients and controls. In patients, gyrification of the insula significantly predicted the symptom severity measured using Yale-Brown Obsessive-Compulsive Scale (YBOCS).

CONCLUSIONS

An alteration in the cortical surface anatomy is an important feature of OCD seen in unmedicated samples that relates to the severity of the illness. The results underscore the presence of a neurodevelopmental aberration underlying the pathophysiology of OCD.

Elevated serine protease HtrA1 inhibits cell proliferation, reduces invasion, and induces apoptosis in esophageal squamous cell carcinoma by blocking the nuclear factor-κB signaling pathway

Emerging evidence has demonstrated that high-temperature requirement protein A1 (HtrA1) appears to be involved in several important biological processes in mammals such as growth, apoptosis, embryogenesis, invasion, metastasis, and cancer and has been verified to be reduced in a variety of human tumors. However, its precise functions and molecular mechanisms in esophageal squamous cell carcinoma (ESCC) remain unclear. Here, we detected HtrA1 level in ESCC tissues and cells and investigated the biological roles of HtrA1 in ESCC. We found that expressions of HtrA1 mRNA and protein in ESCC tissues and cells were significantly lower than those in normal esophageal epithelial tissues and cells (P < 0.05). Expressions of HtrA1 mRNA and protein were closely associated with TNM staging and lymph node metastasis (P < 0.05). Additionally, the survival rate of patients with low HtrA1 level was lower than those patients with high HtrA1 level (P < 0.05). Elevated HtrA1 level markedly inhibited cell proliferation in vitro and in vivo, reduced cell invasion in vitro, and induced cell apoptosis. Notably, HtrA1 overexpression inhibited phosphorylation levels of IκBα and p65 subunit of the NF-κB signaling pathway, but increased total IκBα level, coupled with decreases of Ki-67, Bcl-2, Bcl-xL, cyclin D1, and MMP-9 proteins and increase of caspase-3 activity. Overall, these data suggest that HtrA1 may play critical roles in the tumorgenesis and progression of ESCC, and HtrA1 overexpression exerts its anti-tumor effect by blocking the NF-κB signaling pathway; thus, manipulation of HtrA1 may be an effective molecular target for ESCC treatment.

Transcriptional regulatory networks in human lung adenocarcinoma

Lung adenocarcinoma (AC) is the most common histological subtype of lung cancer worldwide and its absolute incidence is increasing markedly. Transcriptional regulation is one of the most fundamental processes in lung AC development. However, high-throughput functional analyses of multiple transcription factors and their target genes in lung AC are rare. Thus, the objective of our study was to interpret the mechanisms of human AC through the regulatory network using the GSE2514 microarray data. Our results identified the genes peroxisome proliferator activated receptor-γ (PPARG), CCAAT/enhancer binding protein β (CEBPB), ets variant 4 (ETV4), Friend leukemia virus integration 1 (FLI1), T-cell acute lymphocytic leukemia 1 (TAL1) and nuclear factor of kappa light polypeptide gene enhancer in B-cells 1 (NFKB1) as hub nodes in the transcriptome network. Among these genes, it appears that: PPARG promotes the PPAR signaling pathway via the upregulation of lipoprotein lipase (LPL) expression, but suppresses the cell cycle pathway via downregulation of growth arrest and DNA-damage-inducible, γ (GADD45G) expression; ETV4 stimulates matrix metallopeptidase 9 (MMP9) expression to induce the bladder cancer pathway; FLI upregulates transforming growth factor, β receptor II (TGFBR2) expression to activate TGF-β signaling and upregulates cyclin D3 (CCND3) expression to promote the cell cycle pathway; NFKB1 upregulates interleukin 1, β (IL-1B) expression and initiates the prostate cancer pathway; CEBPB upregulates IL-6 expression and promotes pathways in cancer; and TAL1 promotes kinase insert domain receptor (KDR) expression to promote the TGF-β signaling pathway. This transcriptional regulation analysis may provide an improved understanding of the molecular mechanisms and potential therapeutic targets in the treatment of lung AC.

Endostar plus gemcitabine/cisplatin (GP) with maintenance endostar as first-line therapy for advanced non-small cell lung cancer (NSCLC): Preliminary results of a phase II study

e18033

Background: Endostar is a recombinant human endostatin. We conducted a multi-centre trial to investigate the efficacy and safety of Endostar plus GP with maintenance Endostar as first- line therapy for advanced NSCLC Methods: Chemotherapy-naïve patients with histologically or cytologically confirmed, measurable, stage ‡W NSCLC were enrolled from 11 centers in China. All patients received gemcitabine 1,000 mg/m2 (days 1 and 8) plus cisplatin 25 mg/m2 (days 1-3) every 21 days. Patients achieving objective response or disease stabilization following initial 2 cycles of GP were given Endostar (15 mg) on days 1–14 every 21 days in combination with another 2 cycles of GP. Then, patients who did not progress received maintenance endostar (15 mg) on days 1–14 every 21 days until disease progression or unacceptable toxicity. The primary was progression-free survival (PFS). Secondary endpoints were treatment-related toxicity and median overall survival (OS). Results: Between Oct.2008 and Sep. 2010, we enrolled 85 patients (median age: 52.2 years; median KPS score: 80; stage IV with M1b: 94.1%; adenocarcinoma: 64.6%). 48 (56.5%) patients complete 4 cycles of GP plus 2 cycles of Endostar and 33(38.8%) patients were treated with maintenance Endostar. For 38 patients receiving maintenance therapy, median PFS throughout the study period by independent review was 5.97 month and 1-year survival rate was 75.8%. Median PFS were 3.97 months for all 85 patients, while 1-year survival rate was 64.7%. No treatment related death occurred. 28(32.9%) patients had at least one grade 3/4 adverse events; the grade 3/4 hematologic toxicity included anemia in 32.9%, thrombocytopenia in 25.9%, neutropenia in 4.7% of patients. The grade 3/4 non-hematologic toxicities included nausea/vomiting in 18.8%, rash in 5.9%, hepatic impairment in 3.5%, diarrhea in 1.2%, hemorrhage in 1.2% of patients. Conclusions: This regimen, involving maintenance Endostar, didn’t significantly improve PFS in advanced NSCLC patients as compared to historic control although associated acceptable toxicity has been demonstrated

Clinical implication of elevated human cervical cancer oncogene-1 expression in esophageal squamous cell carcinoma

The human cervical cancer oncogene 1 (HCCR-1), a novel human oncoprotein, has been shown to be upregulated in various human tumors and plays a critical role in tumorigenesis and tumor progression. Here, the authors investigated HCCR-1 level in esophageal squamous cell carcinoma (ESCC) tissues and assessed the correlation between HCCR-1 level and prognosis of the patients with ESCC. HCCR-1 levels were investigated by immunohistochemistry, in situ hybridization, real-time quantitative RT-PCR and Western blotting methods; Kaplan-Meier curve was used to evaluate the prognostic value of HCCR-1 level in patients with ESCC using log-rank test. HCCR-1 displayed high levels in ESCC tissues compared to squamous dysplasia tissues and normal esophageal epithelial tissues. No significant correlation was observed between the levels of HCCR-1 mRNA and protein and gender and age (all p>0.05) but obviously related to histological grade, clinical stage, and lymph node metastasis (all p<0.001). Moreover, the survival rate of the patients with low HCCR-1 levels was higher than that of the patients with high HCCR-1 levels (both p<0.05). These data demonstrate that HCCR-1 may be used as a novel predictor for the prognosis of the patients with ESCC.

Differential efficacy of gefitinib across age groups in treatment of advanced lung adenocarcinoma

OBJECTIVE

To compare the efficacy of gefitinib monotherapy across different age groups of patients with advanced lung adenocarcinoma.

METHODS

Clinical data of patients (mostly Chinese) with advanced lung adenocarcinoma who were non-smokers or light smokers and had received oral gefitinib (250mg/d) between October 2006 and December 2009 were reviewed retrospectively. The 93 enrolled patients (25 male and 68 female; median age, 62.5 years), were divided into three age groups: < or = 49 years (n = 22), 50-69 years (n = 53), and > or = 70 years (n = 18). Among them, 84 patients had received at least one chemotherapy regimen previously. The objective response rate (ORR), time to disease progression (TTP), median overall survival (MOS) and adverse effects in response to gefitinib treatment were analyzed in the above age groups.

RESULTS

Out of 93 patients, a complete response was seen in 5 patients, partial response in 43 patients, stable disease in 36 patients, and disease progression in 9 patients. ORR was 51.6%, and the disease control rate (DCR) was 90.3%. No significant correlation was observed between ORR of gefitinib treatment and the baseline clinical characteristics of the patients. The median TTP was 12.6 months, and median overall survival (MOS) was 23.4 months. Gefitinib treatment-related UP was prolonged with increasing age: 8.2 months, 14.2 months and 18.2 months in the age groups of < or = 49-years, 50-69-years and > or = 70-years, respectively (log-rank P = 0.002). MOS in the three age groups was 20.4 months, 23.6 months and 22.0 months, respectively (P > 0.05). The most common adverse effects were rash and diarrhoea, and rash seemed to be correlated with ORR (ORR = 2.631; p = 0.044, 95% CI: 1.025-6.753).

CONCLUSIONS

In Asian patients with advanced lung adenocarcinoma who were non-smokers or light smokers and were treated with gefitinib, progression-free survival was correlated with age. Elderly patients (> or = 70 years) seemed more likely to benefit from gefitinib treatment.

Be alert to tuberculosis-mediated glomerulonephritis: a retrospective study

Mycobacterium tuberculosis infection causing glomerulonephritis is a rare disorder. This retrospective study analyzed the clinical characteristics of patients diagnosed with tuberculosis-mediated glomerulonephritis (TB-GN) between 2002 and 2009, as well as the diagnostic tools used. These findings were then compared with those of patients with primary glomerulonephritis (P-GN). The records of all patients were reviewed. The diagnosis of TB-GN was based on renal hematuria and/or proteinuria and cure after antituberculosis therapy alone plus urine culture positive for M. tuberculosis, demonstration of typical tubercle granulomas on renal biopsy specimens, or the detection of M. tuberculosis DNA by polymerase chain reaction (PCR) on renal specimens. Forty-six patients with TB-GN and 49 patients with P-GN were included. Compared with patients in the P-GN group, most (76%) patients with TB-GN had a history of TB. Systemic symptoms were much more frequent in patients with TB-GN than local genitourinary symptoms. Serological testing showed a statistical difference between the two groups. Immunoglobulin A nephropathy was found in the majority (72%) of patients with TB-GN. M. tuberculosis DNA detection was positive in 39 (84.8%) patients, a much higher positive rate of diagnosis than that with urine culture for M. tuberculosis. The manifestation of TB-GN is atypical and nonspecific. It warrants a high index of suspicion when patients with renal hematuria and proteinuria fail to respond to standard treatments for P-GN. Clinicians should pay close attention to the medical history and results of special laboratory tests. M. tuberculosis DNA detection on renal biopsy specimens should be considered in order to confirm the diagnosis of TB-GN.

Arsenic trioxide re-sensitizes ERα-negative breast cancer cells to endocrine therapy by restoring ERα expression in vitro and in vivo

Approximately one-third of breast cancers lack estrogen receptor α (ERα) because of the hypermethylation of the CpG island in the receptor's promoter. These tumors are associated with poorer histological differentiation, a higher growth fraction, are rarely responsive to endocrine therapy and have a worse clinical outcome. Thus, re-expression of ERα in ERα-negative breast cancers may restore the sensitivity of antiestrogen therapy. The ERα-negative breast cancer cell line MDA-MB-435s was treated with different concentrations of arsenic trioxide (As2O3). MS-PCR was used to detect the change in the methylation status of ERα. RT-PCR, immunohistochemistry and Western blot analyses were used to detect changes in the mRNA and protein expression of DNA methyl-transferase-1 (DNMT1) and ERα. Cell proliferation was examined using the MTT assay. A xenograft model in nude mice was used to further examine the results we observed in vitro. The ERα gene was demethylated after As2O3 treatment of MDA-MB-435s cells. RT-PCR, immunohistochemistry and Western blot analyses revealed that DNMT1 expression was inhibited and ERα was re-expressed in a concentration-dependent manner after As2O3 treatment. The MTT assay showed that cell proliferation was significantly suppressed after exposure to different concentrations of As2O3. Addition of tamoxifen (TAM) further suppressed levels of cell proliferation. In vivo, the xenograft tumor volumes of As2O3-treated mice were smaller than those observed in untreated and TAM-treated mice. Treatment with a combination of As2O3+TAM resulted in further suppression. As2O3 can act as a demethylation agent to restore ERα expression in ERα-negative breast cancer cells and re-sensitize these cells to endocrine therapy in vitro and in vivo.