Salman Farshchi-Heydari

Enhanced Delivery of Cisplatin to Intraperitoneal Ovarian Carcinomas Mediated by the Effects of Bortezomib on the Human Copper Transporter 1

Purpose: The copper transporter 1 (CTR1) is a major influx transporter for platinum drugs. However, the accumulation of cisplatin in human ovarian carcinoma cells is limited by the fact that cisplatin triggers the down-regulation and proteasomal degradation of CTR1, thereby limiting its own uptake. We sought to determine whether proteasome inhibition using bortezomib would prevent human CTR1 (hCTR1) degradation and increase platinum accumulation in ovarian cancer cells. Experimental Design: The effects of bortezomib on human hCTR1 expression and cisplatin accumulation were measured by Western blot, flow cytometric, and confocal digital imaging analyses. Platinum accumulation was measured by inductively coupled plasma mass spectrometry and bortezomib concentrations by liquid chromatography/mass spectrometry. Results: Bortezomib blocked the cisplatin-induced down-regulation of hCTR1 in a concentration-dependent manner and increased cisplatin uptake 1.6- to 2.4-fold. Median effect analysis showed a combination index of 0.37 at 50% cell kill, indicating a high level of synergy. The effect of bortezomib was muted in cells lacking both alleles of CTR1, showing that bortezomib was working primarily through its effect on blocking hCTR1 degradation. I.p. administration of bortezomib produced a peritoneal/plasma area under the curve ratio of 252 in a murine model. I.p. administration of bortezomib before i.p. cisplatin increased platinum accumulation in peritoneal tumors by 33% (P = 0.006). Conclusions: Proteasomal inhibition prevented cisplatin-induced down-regulation of hCTR1 in ovarian cancer cells and enhanced drug uptake and cell killing in a synergistic manner. Bortezomib shows a large pharmacologic advantage when administered i.p. There is a strong rationale for the combined i.p. administration of bortezomib and cisplatin.

Tumor platinum concentration following intraperitoneal administration of cisplatin versus carboplatin in an ovarian cancer model

OBJECTIVE Current intraperitoneal (IP) regimens for the treatment of ovarian cancer rely on cisplatin (DDP) whereas intravenous regimens rely on carboplatin (CBDCA). A major question in the field is whether CBDCA can replace DDP for IP treatment. We compared the uptake of IP administered DDP and CBDCA into human ovarian carcinoma nodules of various sizes growing on the peritoneal surface of nu/nu mice. METHODS Human 2008 cells expressing GFP were inoculated IP in nu/nu mice. When small tumor nodules became visible by external imaging, a maximum tolerated dose of DDP, or either an equimolar or equitoxic dose of CBDCA, was injected IP. Platinum (Pt) concentration in tumor nodules was measured by inductively coupled plasma mass spectrometry. RESULTS A total of 749 tumors harvested from 33 mice were analyzed for Pt concentration. DDP produced a 3.4-fold higher level of Pt in tumor nodules when compared to an equimolar dose of CBDCA (p=0.02). However, when DDP and CBDCA were injected at doses that were equitoxic to the mice, tumor Pt levels were equivalent (p=0.63). Although Pt concentrations of equal-sized nodules were highly variable, tumor Pt content (ng Pt/mg tumor) decreased with increasing nodule size following IP DDP, an effect not seen with IP administration of equitoxic doses of CBDCA (p<0.001). CONCLUSIONS These results suggest that IP CBDCA has comparable or better drug penetration when compared to DDP given at equitoxic doses, and thus provide support for replacing DDP with CBDCA in the IP treatment of patients with ovarian cancer.

In vivo simultaneous monitoring of two fluorophores with lifetime contrast using a full-field time domain system

Optical molecular imaging of small animals in vivo has witnessed dramatic growth during the past decade. Most commercial systems are based on continuous wave technology and measure solely bioluminescence or fluorescence intensity. Time domain (TD) technology enables the measurement of both intensity and fluorescence lifetime as an additional imaging metric. We have developed a novel, in-house, full-field TD system with dramatically faster acquisition times than available from a commercial TD system. Recent in vivo data from a mouse imaged with the full-field TD system has demonstrated the potential to monitor and discriminate two fluorophores injected simultaneously based on their fluorescence lifetime contrast.

Analytical Method for the Fast Time-Domain Reconstruction of Fluorescent Inclusions In Vitro and In Vivo

A novel time-domain optical method to reconstruct the relative concentration, lifetime, and depth of a fluorescent inclusion is described. We establish an analytical method for the estimations of these parameters for a localized fluorescent object directly from the simple evaluations of continuous wave intensity, exponential decay, and temporal position of the maximum of the fluorescence temporal point-spread function. Since the more complex full inversion process is not involved, this method permits a robust and fast processing in exploring the properties of a fluorescent inclusion. This method is confirmed by in vitro and in vivo experiments.

Analysis of the fluorescence temporal point-spread function in a turbid medium and its application to optical imaging

A time-domain optical method to evaluate the concentration (n), lifetime (tau), and depth (d) of a fluorescent inclusion is described by the complete analysis of the fluorescence temporal point-spread function (TPSF). The behavior of parameters in the fluorescence TPSF is explored, and we demonstrate the method with experimental data from a localized fluorescent inclusion in scattering media to recover images of n, tau, and d. The method has potential application for in vivo fluorescence imaging.

Quadrature Detection of Ultrasound-Modulated Photons with a Gain-Modulated, Image-Intensified, CCD Camera

Acousto-optic imaging promises to provide in vivo images of optical contrast but with the superior spatial reso- lution of ultrasound imaging. Here we present novel quadrature detection of ultrasound-modulated photons with a gain- modulated, image-intensified, CCD camera. The additional detection of ultrasound-modulated fluorescence photons dem- onstrates potential for in vivo acousto-optic molecular imaging.

Preclinical Evaluation of Robotic-Assisted Sentinel Lymph Node Fluorescence Imaging

An ideal substance to provide convenient and accurate targeting for sentinel lymph node (SLN) mapping during robotic-assisted surgery has yet to be found. We used an animal model to determine the ability of the FireFly camera system to detect fluorescent SLNs after administration of a dual-labeled molecular imaging agent. Methods: We injected the footpads of New Zealand White rabbits with 1.7 or 8.4 nmol of tilmanocept labeled with 99mTc and a near-infrared fluorophore, IRDye800CW. One and 36 h after injection, popliteal lymph nodes, representing the SLNs, were dissected with the assistance of the FireFly camera system, a fluorescence-capable endoscopic imaging system. After excision of the paraaortic lymph nodes, which represented non-SLNs, we assayed all lymph nodes for radioactivity and fluorescence intensity. Results: Fluorescence within all popliteal lymph nodes was easily detected by the FireFly camera system. Fluorescence within the lymph channel could be imaged during the 1-h studies. When compared with the paraaortic lymph nodes, the popliteal lymph nodes retain greater than 95% of the radioactivity at both 1 and 36 h after injection. At both doses (1.7 and 8.4 nmol), the popliteal nodes had higher (P < 0.050) optical fluorescence intensity than the paraaortic nodes at the 1- and 36-h time points. Conclusion: The FireFly camera system can easily detect tilmanocept labeled with a near-infrared fluorophore at least 36 h after administration. This ability will permit image acquisition and subsequent verification of fluorescence-labeled SLNs during robotic-assisted surgery.

Cold wall effect eliminating method to determine the contrast recovery coefficient for small animal PET scanners using the NEMA NU-4 image quality phantom

The contrast recovery coefficients (CRC) were evaluated for five different small animal PET scanners: GE Explore Vista, Genisys4, MiniPET-2, nanoScan PC and Siemens Inveon. The NEMA NU-4 2008 performance test with the suggested image quality phantom (NU4IQ) does not allow the determination of the CRC values for the hot regions in the phantom. This drawback of NU4IQ phantom motivated us to develop a new method for this purpose. The method includes special acquisition and reconstruction protocols using the original phantom, and results in an artificially merged image enabling the evaluation of CRC values. An advantageous feature of this method is that it stops the cold wall effect from distorting the CRC calculation. Our suggested protocol results in a set of CRC values contributing to the characterization of small animal PET scanners. GATE simulations were also performed to validate the new method and verify the evaluated CRC values. We also demonstrated that the numerical values of this parameter depend on the actual object contrast of the hot region(s) and this mainly comes from the spillover effect. This effect was also studied while analysing the background activity level around the hot rods. We revealed that the calculated background mean values depended on the target contrast in a scanner specific manner. Performing the artificially merged imaging procedure and additional simulations using the micro hollow sphere (MHS) phantom geometry, we also proved that the inactive wall around the hot spheres can have a remarkable impact on the calculated CRC. In conclusion, we have shown that the proposed artificial merging procedure and the commonly used NU4IQ phantom prescribed by the NEMA NU-4 can easily deliver reliable CRC data otherwise unavailable for the NU4IQ phantom in the conventional protocol or the MHS phantom.