miR-141 is involved in BRD7-mediated cell proliferation and tumor formation through suppression of the PTEN/AKT pathway in nasopharyngeal carcinoma

Bromodomain containing 7 (BRD7) was identified as a nuclear transcriptional regulatory factor. BRD7 functions as a tumor suppressor in multiple cancers, including nasopharyngeal carcinoma (NPC). In this study, we reported a novel mechanism of BRD7 in NPC progression. We demonstrated that the expression of miR-141 was remarkably increased in NPC tissues and was negatively correlated with the expression of BRD7 and the survival rate of NPC patients. Decreased expression levels of miR-141, including the primary, the precursor and the mature forms of miR-141, were found in BRD7-overexpressing HEK293, 5-8F and HNE1 cells compared the control cells, while there was no obvious effect on the expression levels of the two critical enzymes Drosha and Dicer. BRD7 can negatively regulate the promoter activity of miR-141, while no obvious binding site of BRD7 was found in the potential promoter region of miR-141. Moreover, ectopic expression of miR-141 can significantly promote cell proliferation and inhibit apoptosis in NPC, and rescuing the expression of miR-141 in BRD7-overexpressing NPC cells could partially reverse the tumor suppressive effect of BRD7 on cell proliferation and tumor growth in vitro and in vivo. Furthermore, the activation of the PTEN/AKT pathway mediated by the overexpression of BRD7 could be inhibited by rescuing the expression of miR-141, which accordingly results in the partial restoration of cell proliferation and tumor growth. Our findings demonstrate that the BRD7/miR-141/PTEN/AKT axis has critical roles in the progression of NPC and provide some promising targets for the diagnosis and treatment of NPC.

Abstract P5-08-38: Low lactate dehydrogenase B expression correlates with decreased distant-metastasis free- and recurrence-free survival post-chemotherapy in basal-like breast cancer

Background:

Metabolism is an important differentiating feature of cancer cells. Lactate dehydrogenases (LDH A/B) are metabolically important proteins involved in the critical inter-conversion of pyruvate to lactate and vice versa. Several reports suggest that LDHB levels are elevated in TNBC, compared to other breast cancer subtypes. However, we recently published that LDHB levels are low in TNBC cell lines and restoring LDHB results in decreased cell proliferation, oxidative phosphorylation, and reversal of EMT. Furthermore, in a small patient cohort, we have shown that although LDHB levels are higher in TNBC patients compared to non-TNBC patients, LDHB levels where consistently lower when compared to LDHA levels. Thus, we set out to determine if either "Hi" or "Low" LDHA and LDHB levels effect patient survival.

Methods:

Utilizing the publically available datasets contained within kmplot,which contains gene expression data and relapse free and overall survivall, we determined mean levels of LDHA and LDHB in breast cancer patients. To analyze the prognostic value, patient samples were split into two groups based upon expression above the mean (considered high expressors, "Hi") or below the mean (considered low expressors, "Low"). The two patient cohorts were compared by a Kaplan-Meier survival plot, and the hazard ratio with 95% confidence intervals and logrank P value calculated. Groups were further stratified based upon LDH levels prior to- and post-chemotherapy.

Results:

We found that in patients with luminal A and luminal B breast cancer, there were no significant changes in either LDHA (p=0.1) or LDHB (p=0.21) on distant metastasis-free (DMFS) or recurrence–free (RFS) survival. However, in the basal subtype (i.e. patients with ER negative and PR negative breast cancer), low levels of LDHB was significantly associated with poorer DMFS (p=0.025) (n=240) prior to chemotherapy and both DMSF (p=0.048) (n=176) and RFS (p=0.0082) (n=388) post-chemotherapy. Examining the mean expression values for each of these patient populations, we did not observe any significant changes in DMSF or RFS pre or post-chemotherapy, suggesting an intrinsic feature of basal-like patients with low LDHB expression to have a more aggressive phenotype. Interestingly, we did observe significance in RFS (n=581, p=0.0043) in patient with "Hi" LDHA expression pre-chemotherapy, however there was no significant associations of LDHA with RFS (p=0.19) (n=388) or DMSF (n=176, p=0.75) post-chemotherapy.

Conclusion:

These findings, coupled with our cell line data, showing overexpressing LDHB in TNBC cell lines results in decreased proliferation with increased mitochondrial damage and apoptosis, suggests that lower levels of LDHB expression is indeed associated with an aggressive breast cancer phenotype that undergoes EMT and the Warburg effect. This could contribute to the lack of pathological response after chemotherapy and thus increased risk for later metastasis. Additionally, given the very large number of patients examined within these independent datasets, these findings further suggest that low LDHB expression is a robust prognostic biomarker of clinical outcome in patients with a basal-like phenotype.

Citation Format: Dean-Colomb W, Tan M, Tang W, Ambs S, Yates C. Low lactate dehydrogenase B expression correlates with decreased distant-metastasis free- and recurrence-free survival post-chemotherapy in basal-like breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-08-38.

Transmission performance improvement using random DFB laser based Raman amplification and bidirectional second-order pumping

We demonstrate that a distributed Raman amplification scheme based on random distributed feedback (DFB) fiber laser enables bidirectional second-order Raman pumping without increasing relative intensity noise (RIN) of the signal. This extends the reach of 10 × 116 Gb/s DP-QPSK WDM transmission up to 7915 km, compared with conventional Raman amplification schemes. Moreover, this scheme gives the longest maximum transmission distance among all the Raman amplification schemes presented in this paper, whilst maintaining relatively uniform and symmetric signal power distribution, and is also adjustable in order to be highly compatible with different nonlinearity compensation techniques, including mid-link optical phase conjugation (OPC) and nonlinear Fourier transform (NFT).

Demonstration of post-growth wavelength setting of VCSELs using high-contrast gratings

We demonstrate, for the first time, post-growth wavelength setting of electrically-injected vertical-cavity surface-emitting lasers (VCSELs) by using high-contrast gratings (HCGs) with different grating parameters. By fabricating HCGs with different duty cycle and period, the HCG reflection phase can be varied, in effect giving different optical cavity lengths for HCG-VCSELs with different grating parameters. This enables fabrication of monolithic multi-wavelength HCG-VCSEL arrays for wavelength-division multiplexing (WDM). The GaAs HCG is suspended in air by removing a sacrificial layer of InGaP. Electrically-injected 980-nm HCG-VCSELs with sub-mA threshold currents indicate high reflectivity from the GaAs HCGs. Lasing over a wavelength span of 15 nm was achieved, enabling a 4-channel WDM array with 5 nm channel spacing. A large wavelength setting span was enabled by an air-coupled cavity design and the use of only the HCG as top mirror.

pulSED: pulsed sonoelectrodeposition of fractal nanoplatinum for enhancing amperometric biosensor performance

A technique for deposition of fractal nanometal as a transducer in electrochemical sensing is described. The effect(s) of duty cycle and deposition time were explored, and two sensors are demonstrated.

Abstract AS03: Epithelial-mesenchymal transition driven by transcriptional feedback loops contributes to intertumoral molecular heterogeneity in the metastasis and relapse of epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is highly heterogeneous with five molecular subgroups, Epi-A, Epi-B, Mes, Stem-A and Stem-B, being identified. The mechanisms behind the clonal evolution and intertumoral molecular heterogeneity are not fully elucidated. Previously, we performed EOC profiling meta-analysis to identify epithelial-mesenchymal transition (EMT) as the crucial mechanism for molecular heterogeneity. Transcription factors SNAI1, SNAI2, ZEB1, ZEB1, TWIST1, and GRHL2 were identified as crucial regulators for the Mes subtype which has undergone EMT. Here, we utilized three in-vitro EOC cell lines, PEO1, OVCA420, and OVCA429, to model the EMT-driven clonal evolution by manipulating the expression levels of these EMT transcriptional regulators. We analysed the molecular subtypes of matched primary tumor versus peritoneal metastases. Six out of 11 pairs showed concordant molecular subtypes. We also analysed a dataset of matched primary tumor versus omental metastases. Four out of 9 pairs showed concordant molecular subtypes. Among the 10 pairs showing a shift of molecular subtypes, 5 out of 5 omental metastases were designated as Mes. The variation in the evolution of molecular heterogeneity can be explained by the differences in the EMT transcriptional cross-regulation of the in-vitro models. Manipulating EMT regulators in PEO1 did not induce any transcriptional cross-regulation with no molecular subtype switching observed. However, manipulating EMT regulators in OVCA420 and OVCA429 caused hierarchical transcriptional control and feedback loop regulation, respectively. The OVCA429 model showed molecular subtype switch from Epi-A to Mes. In conclusion, the heterogeneity caused by EMT-driven clonal evolution is the consequence of transcriptional feedback loops of EMT regulators.

Citation Format: Chung VY, Tan M, Tan TZ, Kuay KT, Ye J, Thiery JP & Huang RY. Epithelial-mesenchymal transition driven by transcriptional feedback loops contributes to intertumoral molecular heterogeneity in the metastasis and relapse of epithelial ovarian cancer [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr AS03.

A phase III study of belagenpumatucel-L, an allogeneic tumour cell vaccine, as maintenance therapy for non-small cell lung cancer

BACKGROUND

Treatment options after first-line chemotherapy are limited in non-small cell lung cancer (NSCLC). Belagenpumatucel-L is a therapeutic vaccine comprised of 4 transforming growth factor (TGF)-β2-antisense gene-modified, irradiated, allogeneic NSCLC cell lines that may be useful for maintenance after initial treatment.

METHODS

Stage III/IV NSCLC patients who did not progress after platinum-based chemotherapy were randomised 1:1 to receive maintenance belagenpumatucel-L or placebo. Patients were eligible for randomisation between one and four months from the end of induction chemotherapy. The primary endpoint was overall survival.

RESULTS

This phase III trial enrolled 270 patients in the belagenpumatucel-L arm and 262 in the control arm. Belagenpumatucel-L was well tolerated with no serious safety concerns. There was no difference in survival between the arms (median survival 20.3 versus 17.8months with belagenpumatucel-L versus placebo, respectively; hazard ratio (HR) 0.94, p=0.594). There were also no differences in progression-free survival (4.3months versus 4.0 for belagenpumatucel-L vs placebo, respectively; HR 0.99, p=0.947). A prespecified Cox regression analysis demonstrated that the time elapsed between randomisation and the end of induction chemotherapy had a significant impact on survival (p=0.002) and that prior radiation was a positive prognostic factor (median survival 28.4months with belagenpumatucel-L versus 16.0months with placebo; HR 0.61, p=0.032).

CONCLUSIONS

Although the overall trial did not meet its survival endpoint, improved survival for belagenpumatucel-L is suggested in patients who were randomised within 12weeks of completion of chemotherapy and in those who had received prior radiation. Further studies of belagenpumatucel-L in NSCLC are warranted.

SIRT1/PGC-1α signaling protects hepatocytes against mitochondrial oxidative stress induced by bile acids

Oxidative stress and mitochondrial dysfunction are hypothesized to contribute to the pathogenesis of chronic cholestatic liver diseases. Silent information regulator 1 (SIRT1) attenuates oxidative stress and improves mitochondrial biogenesis in numerous mitochondrial-related diseases; however, a functional role for SIRT1 in chronic liver cholestasis, characterized by increased levels of toxic bile acids, remains unknown. We show decrease in SIRT1 levels and its activity and impairment of mitochondrial biogenesis in the liver of patients with extrahepatic cholestasis. Moreover, we found that glycochenodeoxycholic acid (GCDCA) stimulated cytotoxicity, disrupted the mitochondrial membrane potential, increased reactive oxygen species production, and decreased mitochondrial mass and mitochondrial DNA content in L02 cells. Consistent with this finding, GCDCA was found to decrease SIRT1 protein expression and activity, thus promoting the deacetylation of peroxisome proliferator-activated receptor gamma, coactivator 1 alpha (PGC-1α), a key enzyme involved in mitochondrial biogenesis and function. Conversely, GCDCA-induced mitochondrial injury was efficiently attenuated by SIRT1 overexpression. In summary, these findings indicate that the loss of SIRT1 may play a crucial role in the pathogenesis of liver damage observed in patients with extrahepatic cholestasis. The findings also indicate that genetic supplementation of SIRT1 can ameliorate GCDCA-induced hepatotoxicity through the activation of PGC-1α-dependent mitochondrial biogenesis.

Robotic trans-abdominal transplant nephrectomy for a failed renal allograft

Minimally invasive surgery for removal of a failed renal allograft has not previously been reported. Herein, we report the first robotic trans-abdominal transplant nephrectomy (TN). A 34-year-old male with Alport's syndrome lost function of his deceased donor allograft after 12 years and presented with fever, pain over his allograft and hematuria. The operation was performed intra-abdominally using the Da Vinci Robotic Surgical System with four trocars. The total operative time was 235 min and the estimated blood loss was less than 25 cm(3). There were no peri-operative complications observed and the patient was discharged to home less than 24 h postoperatively. The utilization of robotic technology facilitated the successful performance of a minimally invasive, trans-abdominal TN.

Accuracy of diagnostic codes for identifying patients with ulcerative colitis and Crohn's disease in the Veterans Affairs Health Care System

BACKGROUND

International Classification of Diseases-9 (ICD-9) codes are useful in clinical research; however, the validity of ICD-9 codes for inflammatory bowel disease (IBD) patients in multiple centers in the Veterans Affairs Health Care Systems (VA) has not been established. Our aim was to determine the accuracy of ICD-9 codes for Crohn's disease (CD) and ulcerative colitis (UC) in the VA.

METHODS

Patients with a diagnosis of IBD during 1999-2009 were identified by at least one ICD-9 code for CD (555.x) or UC (556.x) at the Houston and Ann Arbor VA Medical Centers and confirmed by chart review. A diagnosis of CD, UC, and IBD, unspecified (IBDU) was determined based on structured review of data in the VA medical records. Positive predictive values (PPV) were calculated for the codes using previously published ICD-9 algorithms.

RESULTS

A total of 1,871 patients were identified with ICD-9 codes for IBD. Of these patients, 1,298 (69 %) were confirmed to have IBD, with 541 CD (41 %), 707 UC (55 %), and 50 IBDU (4 %) patients. An algorithm of 2 or more codes with at least one from an outpatient encounter improved the PPV (0.83 and 0.89 for CD and UC, respectively) compared a single code algorithm (PPV 0.59 and 0.66, respectively).

CONCLUSION

Single ICD-9 codes are inadequate to accurately define IBD patients; however, ICD-9 code algorithms can be used to identify patients with UC or CD with high positive predictive value. The 2 code, at least 1 outpatient code algorithm was observed to have a high PPV and low miss rate.

1.14 Tb/s DP-QPSK WDM polarization-diverse optical phase conjugation

Optical phase conjugation (OPC) of a polarization-multiplexed comb of 10x114Gb/s DP-QPSK signals has been demonstrated for the first time, occupying a spectral bandwidth of >1 THz (~9 nm). The nonlinear element employed for the OPC was highly nonlinear fiber (HNLF) optimized for the suppression of stimulated Brillouin scattering (SBS) and configured in a bi-directional loop offering polarization diversity. Pump power (each way about the loop) and input signal power to the OPC subsystem were optimized at 29.7 dBm and + 3 dBm respectively producing a Q(2) penalty of ≤ 0.9 dB over all conjugate wavelengths, polarizations and output OSNR (up to 20 dB).

Abstract P1-07-07: Targeting reversal of epithelial-mesenchymal transition through FOXM1 inhibition in breast cancer cells

Purpose: Triple-negative breast cancer (TNBC), representing up to 20% of all breast cancer cases, is a highly diverse group of cancer that is associated with an aggressive phenotype, with affected patients having a poorer prognosis. Its treatment has been challenging due to its heterogeneity and the absence of well-defined molecular targets.

Epithelial-to-mesenchymal transition (EMT) is one of the hallmarks of aggressive breast cancers and is associated with increased metastatic potential. TNBCs have been shown to exhibit elevated EMT. Thus, reversal of EMT has been identified as a viable target in the treatment of aggressive breast cancers.

FOXM1 is an oncogenic transcription factor of the Forkhead family and it has a well-defined role in cell proliferation and cell-cycle progression. FOXM1 has been reported to be over-expressed in breast cancer. In prostate cancer, FOXM1 overexpression has been linked to increase EMT. We have previously shown that targeting NF-kB with panepoxydone (PP), an NF-kB inhibitor isolated from Lentinus crinitus (an edible mushroom), has significant antitumor activity against breast cancer cells with a resultant decrease in cell migration and invasion and induction of apoptosis. We have further identified that the FOXM1 promoter has a binding site for NF-kB. Thus, in this study, we investigated whether PP-induced inhibition of breast cancer cell growth could be attributed to FoxM1 activity and EMT reversal.

Experimental Design: The estrogen receptor positive (MCF-7) and three different triple negative (MDA-MB-231, MDA-MB-453, and MDA-MB-468) breast cancer cell lines were selected to observe the effect of PP on FOXM1and EMT markers.

Results: In the current study, we investigated whether panepoxydone- induced inhibition of breast cancer cell growth could be attributed to FoxM1activity and EMT reversal. Breast cancer cells were treated with increasing concentrations of PP and proteins collected after 24 hrs. Panepoxydone treatment significantly reduced FOXM1 expression in MCF-7 and MDA-MB-231 (1.7 and 2.4-fold, respectively, p < 0.05) but not in MDAMB-453 and MDAMB-468 cells when analyzed through western blot analysis. Furthermore, we showed that treatment with PP resulted in alteration of EMT-associated proteins with a significant increase in E-cadherin in all the cell lines (ranging from 1.8 to 4.2-fold, p < 0.05) and a decrease in mesenchymal markers vimentin and zeb1 in the MDA-MB-231 cells (2.5 and 2-fold respectively, p < 0.05).

To further elucidate the relationship between FOXM1 on EMT reversal, we then silenced FOXM1 in MDA-MB-231 cells and evaluated its effect on the EMT-associated markers. Again we noted upregulation of E cadherin (3.5-fold, p< 0.01) and down-regulation of vimentin (4.5-fold, p <0.01) in FOXM1, which was very similar to what was observed in the PP-treated MDA-MB-231 cells.

Conclusion: These studies show, for the first time, the role of FOXM1 in EMT reversal in breast cancer cells. Furthermore, it shows that use of an NF-kB inhibitor, such as panepoxydone, may be helpful in elucidating the relationship between these two transcriptional factors, in the reversal of the EMT phenotype in aggressive breast cancer cells.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-07-07.