Abstract LB-302: Inhibition of STAT3 following systemic delivery of STAT3 antisense oligonucleotide results in target inhibition in tumor and tumor-associated stromal cells and dramatic reduction in circulating pro-tumorigenic cytokines

Constitutive activation of STAT3 has been documented in a broad range of neoplastic tissues. STAT3 is a transcription factor that regulates the expression of numerous genes involved in the proliferation, survival, and metastasis of tumor cells. In addition, STAT3 contributes to tumorigenesis by modulating immune responses mediated by tumor stromal cells in the tumor microenvironment. The immuno-suppressive, pro-tumorigenic effects of STAT3 are regulated by induction or inhibition of several key cytokines. However STAT3 remains a difficult target to drug with conventional approaches. Here, we have studied the effects of selective downregulation of STAT3 in various cancer settings by optimized antisense oligonucleotides (ASOs). We assessed the effects of STAT3 downregulation on the expression of cytokines and the progression of cancer. Initially, the safety of inhibiting STAT3 was demonstrated in tolerability studies, where no notable toxicities were observed despite near complete abrogation of STAT3 expression in the liver following systemic delivery of ASO in both rodents and in non-human primate. ASO treatment led to STAT3 inhibition in tumor cells and several non-tumor stromal cell populations of the tumor. In addition, dramatic reduction in key pro-tumorigenic cytokines including IL-6 and IL-1b was observed in C26 colon cancer-bearing animals, which correlated with the decrease of STAT3 level in tumor and stromal cells. This result suggests that STAT3 might not only transmit the IL-6 signal from upstream pathway, but regulates IL-6 level possibly in an auto-feedback manner. Downregulation of STAT3 also led to the inhibition of IL-6-induced C-reactive protein (CRP) expression, which was recently reported to play a key role in the progression of multiple myeloma (MM). Moreover, inhibition of STAT3 resulted in a significant delay in tumor growth in STAT3-dependent MDA-MB-231 breast cancer and U251 glioblastoma xenograft models following systematic ASO treatment. The results from this study collectively suggest that STAT3 expression can be specifically modulated by ASOs in vivo tumor models and that in addition to effects in tumor cells STAT3 ASOs regulate the balance of tumorigenic cytokines in the tumor microenvironment.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-302. doi:10.1158/1538-7445.AM2011-LB-302

Quantitative and conformational characterization of lysozyme deposited on balafilcon and etafilcon contact lens materials

PURPOSE

To determine whether differences in lysozyme deposition and/or activity exist on worn etafilcon and balafilcon contact lenses following care with a polyquaternium-based system (PQ) or a polyhexanide-based system (PHMB).

METHODS

Following acid-based deposit extraction, lysozyme concentration was determined via Western blotting and lysozyme activity was determined by a micrococcyl assay.

RESULTS

Lysozyme deposition on etafilcon lenses was greater following disinfection with the PHMB-based system (1551 +/- 371 micro g/lens vs 935 +/- 271 micro g/lens; p < 0.001). Deposition on balafilcon lenses was not influenced by the care regimen (10 +/- 3.5 micro g/lens vs 10 +/- 5 micro g/lens; p = 0.89). For both materials, the percentage of denatured lysozyme was greater when they were exposed to the PHMB-based system (28 vs 21%; p = 0.05 (etafilcon) and 57 vs 40%; p = 0.04 (balafilcon)).

CONCLUSIONS

The quantity and conformation of lysozyme deposited on hydrogel contact lens materials is significantly influenced by both lens material and care regimen.

A validation of intracellular pH measurements in fish exposed to hypercarbia: the effect of duration of tissue storage and efficacy of the metabolic inhibitor tissue homogenate method

This study assessed the effect of tissue storage duration and accuracy of the metabolic inhibitor tissue homogenate (MITH) method on intracellular pH (pHi) values of tissues of white sturgeon Acipenser transmontanus during hypercarbia. No effect of storage in liquid nitrogen of up to 30 days was observed and MITH appears appropriate for measurement of pH in fish exposed to up to 10% CO2 (10000 Pa pCO2).

Relation of exhaled nitric oxide levels to development of bronchopulmonary dysplasia

OBJECTIVE

To test the hypothesis that exhaled nitric oxide levels on day 28 and changes in exhaled nitric oxide levels in the neonatal period would differ according to whether infants developed bronchopulmonary dysplasia (BPD) and its severity.

DESIGN

Prospective observational study.

SETTING

Tertiary neonatal intensive care unit.

PATIENTS

80 infants (median gestational age 28, range 24-32 weeks), 46 of whom developed BPD.

INTERVENTIONS

Exhaled nitric oxide measurements were attempted on days 3, 5, 7, 14, 21 and 28.

MAIN OUTCOME MEASURES

BPD (oxygen dependency at 28 days), mild BPD (oxygen dependent at 28 days, but not 36 weeks postmenstrual age (PMA)); moderate BPD (oxygen dependent at 36 weeks PMA) and severe BPD (respiratory support dependent at 36 weeks PMA).

RESULTS

On day 28, exhaled nitric oxide levels were higher in infants with BPD compared to those without BPD (p<0.001) and there was a linear trend in exhaled nitric oxide results as BPD severity increased (p = 0.006). No significances in the change in exhaled nitric oxide levels over the neonatal period were found between the four groups.

CONCLUSION

Exhaled nitric oxide levels are raised in infants with established BPD, particularly in those developing moderate or severe BPD, and may reflect ongoing inflammation.