Real-Time Single-Walled Carbon Nanotube-Based Fluorescence Imaging Improves Survival after Debulking Surgery in an Ovarian Cancer Model

Improved cytoreductive surgery for advanced stage ovarian cancer (OC) represents a critical challenge in the treatment of the disease. Optimal debulking reaching no evidence of macroscopic disease is the primary surgical end point with a demonstrated survival advantage. Targeted molecule-based fluorescence imaging offers complete tumor resection down to the microscopic scale. We used a custom-built reflectance/fluorescence imaging system with an orthotopic OC mouse model to both quantify tumor detectability and evaluate the effect of fluorescence image-guided surgery on post-operative survival. The contrast agent is an intraperitoneal injectable nanomolecular probe, composed of single-walled carbon nanotubes, coupled to an M13 bacteriophage carrying a modified peptide binding to the SPARC protein, an extracellular protein overexpressed in OC. The imaging system is capable of detecting a second near-infrared window fluorescence (1000-1700 nm) and can display real-time video imagery to guide intraoperative tumor debulking. We observed high microscopic tumor detection with a pixel-limited resolution of 200 μm. Moreover, in a survival-surgery orthotopic OC mouse model, we demonstrated an increased survival benefit for animals treated with fluorescence image-guided surgical resection compared to standard surgery.

Abstract 4196: Real-time single-walled nanotube (SWNT)-based imaging system improves tumor detection and survival in ovarian cancer animal model

Residual tumor detection in advanced stage ovarian cancer (OC) represents a critical challenge in the treatment of this disease. Optimal abdominal cytoreduction to reduce tumor to no evidence of macroscopic disease is the main endpoint of tumor debulking surgery, with demonstrated survival advantages, but the current clinically available imaging modalities have shown low tumor detection sensitivity of tumors smaller than 10 mm diameter. Instead, targeted molecule-based imaging systems offer higher detection rate and are likely to extend the aim of complete resection to the microscopic scale. We applied a custom designed imaging system to a preclinical ovarian cancer tumor model and observed higher microscopic tumor detection accuracy and survival advantage compared to non-image guided debulking surgery.

A two component imaging system was developed. The contrast agent is an intra-peritoneal injectable nanomolecular probe, composed of a single walled carbon nanotube (SWNT) coupled with an engineered M13-bacteriophage carrying a modified peptide targeting secreted protein, acidic and rich in cysteine (SPARC), extracellular protein overexpressed in OC. The imaging device system is capable of detecting SWNT inherent fluorescence in near-infrared second window (NIR2) and of displaying real-time images to guide the intraoperative tumor debulking.

In an orthotopic ovarian cancer animal model, the imaging system detected microscopic tumors in the millimeter and sub-millimeter scale resolution with a mean tumor diameter of 2.1 vs 3.6 mm (p< 0.01) compared to eye detected tumors. The imaging system demonstrated sensitivity of 97.2% and specificity of 69.7%, and a Receiver Operator Area under the Curve of 0.85 + 0.05. In a survival surgery animal model, the imaging guided resection surgery compared to non guided surgery showed a survival advantage for the experimental arm, with median survival time of 41.0 days vs 28.5 days, respectively (HR 0.22, 95% CI of ratio 0.04 to 1.08 Log Rank test: p: 0.063).

The accuracy of the imaging system and its survival advantage are promising. The survival outcome improvement in this preclinical model supports the translation to first-in-human investigation. Moreover, the imaging system accuracy suggests further exploitation in targeted delivery therapies.

Citation Format: Lorenzo Ceppi, YoungJeong Na, Neelkanth M. Bardhan, Andrew Siegel, Nandini Rajan, Angela M. Belcher, Michael J. Birrer. Real-time single-walled nanotube (SWNT)-based imaging system improves tumor detection and survival in ovarian cancer animal model. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4196.

Prognostic significance of Id-1 and its association with EGFR in renal cell cancer

AIMS

Epidermal growth factor receptor (EGFR) is suggested as one of the positive regulators in the invasive progression of renal cell cancer (RCC). Recently, Id-1 (inhibitor of differentiation or DNA binding), a helix-loop-helix transcription factor, has been identified as one of the key factors in the EGFR signalling pathway. The aim of this study was to investigate the significance of Id-1 expression in renal cell cancer and to study its relationship with EGFR.

METHODS AND RESULTS

Id-1 and EGFR expression was examined in tissue microarray (TMA) samples of 107 RCC and 32 normal kidney specimens by immunohistochemistry. Relative Id-1 and EGFR protein expression was quantified by estimating the staining intensity on a four-grade scale. We found that while negative to weak expression of Id-1 and EGFR was observed in non-malignant kidney tissues, most RCCs showed significant positive Id-1 and EGFR expression in tumour cells. In addition, Id-1 immunostaining intensity was positively associated with increased tumour staging, grading and EGFR expression.

CONCLUSION

Overexpression of Id-1 is a novel marker for advanced RCC which is positively correlated with EGFR expression. Our results suggest that Id-1 may play an important role in the development of RCC and indicate that Id-1 is a potential marker of patients with a poor prognosis.

Global analysis of differentially expressed genes in androgen-independent prostate cancer

Progression to androgen independent (AI) is the main cause of death in prostate cancer, and the mechanism is still unclear. By reviewing the expression profiles of 26 prostate cancer samples in a holistic view, we found a group of genes differentially expressed in AI compared with androgen-dependent groups (P-value<0.01, t-test). Focusing on apoptosis, proliferation, hormone and angiogenesis, we found a group of genes such as thioredoxin domain containing 5 , tumor necrosis factor receptor superfamily, member 10a , ribosomal protein S19 and Janus kinase 2 upregulated in AI prostate cancer, could play important roles in the transition from AD to AI and could be biomarkers of prognosis.

Silencing mediator of retinoid and thyroid hormone receptors and activating signal cointegrator-2 as transcriptional coregulators of the orphan nuclear receptor Nur77

For the orphan nuclear receptor subfamily that includes Nur77 (NGFI-B), Nurr1, and NOR-1, no transcriptional coregulators have been identified thus far. In this report, we found that Ca(2+)/calmodulin-dependent protein kinase IV enhances Nur77 transactivation in cotransfections either alone or in synergy with AF2dependent coactivator ASC-2, whereas corepressor silencing mediator for retinoid and thyroid hormone receptors (SMRT) is repressive. Interestingly, Nur77 interacted with SMRT but did not directly bind ASC-2, and accordingly, the putative AF2 core domain of Nur77 did not affect the Nur77 transactivation. SMRT harbors transferable repression domains that associate with various histone deacetylases. Surprisingly, histone deacetylase inhibitor trichostatin A was unable to block the repressive effect of SMRT while dramatically stimulating the Nur77 transactivation. These results suggest that SMRT and ASC-2 are specific coregulators of Nur77 and that SMRT may dynamically compete with a putative adaptor molecule, which links ASC-2 to Nur77, for the identical binding sites within Nur77 in vivo.

Synthesis, DNA cross-linking activity, and cytotoxicity of dimeric mitomycins

Dimeric DNA cross-linking compounds have emerged as important new antitumor agents. We report the synthesis and biochemical evaluation of a select set of dimeric mitomycins in which the two mitomycin units are tethered at either the mitomycin C(7) amino or the aziridine N(1a) positions. Significantly, mitomycin C (1) itself is the prototypical bioreductive DNA cross-linking agent. DNA cross-linking experiments using a denaturing-gel-electrophoresis-based assay showed that the extent of DNA cross-linking for select dimeric mitomycins can exceed that of the parent compound, mitomycin C, and that the reaction proceeds, in part, at the two distal C(1) sites in the mitomycins. The efficiency of DNA cross-linking depended on the nature of the linker and the position of linker unit's attachment. When we compared the efficiency of DNA cross-linking for the dimeric mitomycins with their in vitro cytotoxicities in cultured human tumor cells, we observed a poor correlation. The mitomycins that gave the highest levels of DNA cross-linked adducts displayed the weakest cytotoxicities. These findings determined that the denaturing-gel-electrophoresis-based assay was a poor predictor of cytotoxic activity.