Browsing by Subject "Bladder cancer"

Mild hyperthermia (39°C-43°C) has numerous therapeutic benefits as an adjuvant therapy in the treatment of a variety of tumor types. Hyperthermia increases tumor blood flow and vascular permeability, promoting drug delivery and tumor oxygenation. Hyperthermia enhances the uptake and efficacy of numerous chemotherapeutic agents, including cisplatin, resulting in increased cytotoxicity. In addition to these biological responses, hyperthermia can be used as a drug-release trigger for temperature-sensitive nanoparticles, resulting in an improved and more targeted drug delivery system. Cisplatin was chosen because 1) it shows broad spectrum activity against a wide range of heatable cancers (i.e., those in sites such as the pancreas, colon and rectum, cervix and bladder, and 2) the same hyperthermic temperatures that enable temperature-sensitive lipsome-drug release also enhance cisplatin-induced cytotoxicity.

The role of hyperthermia in enhancing cisplatin delivery and cytotoxicity was investigated at both the cellular and tissue levels. While hyperthermia treatment is applicable to a variety of tumor types, the focus of this work was on bladder cancer. The synergistic effects of hyperthermia and cisplatin were investigated, along with the role of copper transport protein 1 (Ctr1) in this process. In addition, cisplatin was encapsulated within temperature-sensitive liposomes, which were used in combination with hyperthermia for targeted drug delivery. These studies demonstrated that the combination of cisplatin and hyperthermia improved drug delivery, and potentially anti-tumor efficacy, and that targeted delivery was enhanced through incorporation of temperature-sensitive liposomes. As many current methods for administering bladder hyperthermia have drawbacks, such as invasiveness and regional heating, the final aim of this study was to develop and test a less-invasive and more focused preclinical bladder heating device in a rat model.

Hyperthermia sensitizes cells to the cytotoxic effects of the commonly used chemotherapeutic agent cisplatin by increasing drug accumulation and subsequent platinum-DNA adduct formation. However, the molecular mechanisms underlying this enhancement remain unclear. Understanding the fundamental mechanisms involved in the synergistic interaction is necessary to increase the therapeutic benefits of this combination in the clinic. The synergism between the anti-cancer benefits of cisplatin and the drug delivery benefits of hyperthermia may offer a novel and more effective treatment for many cancer patients. We hypothesized that hyperthermia increases cisplatin accumulation and efficacy in part by modulating the function of Ctr1, a major regulator of cellular cisplatin uptake. To test this hypothesis, we examined the significance of Ctr1 during combined hyperthermia and cisplatin therapies and assessed the importance of cisplatin- and hyperthermia-induced Ctr1 multimerization in enhancing cisplatin cytotoxicity. We observed increased Ctr1 multimerization following hyperthermia treatment (41°C) in vitro, compared to normothermic controls (37°C), suggesting that this may be a mechanism for increased cisplatin uptake in heat-treated cells. The impact of increased Ctr1 multimerization was evaluated by measuring platinum accumulation in wild-type (WT) and Ctr1-/- cells. WT cells contained greater levels of platinum compared to Ctr1-/- cells. A further increase in platinum was observed following hyperthermia treatment, but only in the WT cells. Hyperthermia enhanced cisplatin-mediated cytotoxicity in WT cells with a dose-modifying factor (DMF) of 1.8 compared to 1.4 in Ctr1-/- cells. Our data suggest that heat increases Ctr1 activity by increasing multimerization, resulting in enhanced drug accumulation. Although we recognize that the effect of heat on cells is multi-factorial, our results support the hypothesis that Ctr1 is, in part, involved in the synergistic interaction observed with cisplatin and hyperthermia treatment.

In addition to assessing cisplatin delivery at the cellular level, we evaluated cisplatin delivery at the tissue level, using novel cisplatin-loaded temperature-sensitive liposomes. We hypothesized that delivering cisplatin encapsulated in liposomes under hyperthermic conditions would improve the pharmacokinetic profiles of cisplatin, increase drug delivery to the tumor, decrease normal tissue toxicity, and enhance the anti-tumor activity of cisplatin. We successfully prepared temperature-sensitive liposomes loaded with cisplatin and demonstrated that heat (42°C) sensitizes cisplatin-resistant cells to the cytotoxic effects of cisplatin in vitro.

Decreased toxicity was observed in animals treated with the cisplatin liposome (± heat) compared to the free drug treatments. A pharmacokinetic study of cisplatin-loaded temperature-sensitive liposomes and free drug was performed in tumor-bearing mice under normothermic and hyperthermic conditions. Cisplatin half-life in plasma was increased following liposome treatment compared to free cisplatin, and cisplatin delivery to the tumors was greatest in mice that received liposomal cisplatin under hyperthermia. These initial in vivo data demonstrate the potential effectiveness of this cisplatin-loaded liposome formulation in the treatment of certain types of cancer. To assess the anti-cancer efficacy of the liposome treatment, a tumor growth delay study was conducted and demonstrated equivalent efficacy for the cisplatin-loaded temperature-sensitive liposome compared to free drug.

In addition to the liposome work, we developed and evaluated a novel heating device for the bladder. Despite the evidence that hyperthermia is an effective adjuvant treatment strategy, current clinical heating devices are inadequate, warranting the development of a new and improved system. We induced hyperthermia using ferromagnetic nanoparticles and an alternating magnetic field device developed by Actium Biosystems. Initial preclinical studies in a rat model demonstrated preferential bladder heating. However, our preliminary studies show severe toxicity with the direct instillation of the nanoparticles in the bladder, and further studies are needed to potentially modify the nanoparticle coating, the catheterization procedure, as well as to develop a different animal model.

Cancer is a significant threat to human health with more than eight million deaths each year in the world. Therefore, numerous technologies have been implemented or under development to effectively treat cancer.

One novel therapeutic platform is implemented using nanoparticle-mediated photothermal therapy. Gold NanoStars (GNS), are a unique form of gold nanoparticles (GNPs) that have unique therapeutic potential because of their star-shaped geometry. Enhanced light absorption and higher photon-to-heat conversion efficiency are introduced by GNS’s plasmonic properties. In the application of hyperthermia, this photothermal process can be exploited to specifically heat tumors and, more importantly, to amplify the antitumor immune response following the highly immunogenic thermal death of cancer cells. Meanwhile, when combined with immune checkpoint inhibition immunotherapy (IT), this SYnergistic iMmuno PHOtothermal NanotherapY (SYMPHONY) has been shown to reverse tumor-mediated immunosuppression, thereby leading to the treatment of not only primary tumors but also cancer metastasis. This phenomenon is called the “abscopal effect”. However, the immune response has not been clearly quantified yet. Our hypothesis was that different treatment modalities (PTT only, GNS-PTT, IT, SYMPHONY) will trigger different levels of immune response including the decrease of immunosuppressive cells and the influx of cytotoxic cells, which could be observed by imaging immune cell reporters.

Accordingly, two specific aims were set for this study: 1. to develop a pre-clinical murine model to quantify different levels of immune response mimicking the tumor metastatic environment; 2. to quantify immune response following SYMPHONY using imaging analysis techniques.

To achieve the specific aims, window chamber models combined with in vivo fluorescence imaging techniques provide an ideal platform to mimic cancer metastasis in the chamber and longitudinally monitor immune response through the prevalence of fluorescent reporters specifically localized to immune cells of interest. We utilized a dual tumor mouse model, consisting of a primary tumor grown in the flank of the mouse which received the SYMPHONY therapy, as well as a secondary tumor located in the window chamber through which we could image and observe the abscopal response to therapy. In this study, we demonstrate the optical imaging procedure following synergistic immune photothermal therapy (SYMPHONY) of bladder cancer using the immune-GFP-labeled murine window chamber model, for the purpose of quantifying the immune response at this mimicked-tumor metastasis site. Four groups were established: the SYMPHONY group, the photothermal therapy group, the immune therapy group, and the Gold NanoStars (GNS) control group.

Higher immune responses were observed in the tumor regions compared to the non-tumor regions. The in vivo fluorescence imaging along with the window chamber technique demonstrates the feasibility and convenience of following such a longitudinal study like SYMPHONY. However, although temporal changes in reporter intensity were observed, with a limited number of samples, we cannot thus far identify significant differences among the treatment groups. Approaches for further characterizing this model are discussed.

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Bladder cancer has been ranked as one of the top ten and top twenty most commonly occurring cancers in men and women, respectively, with approximately half of the diagnoses being late stage and/or metastatic disease. The current standard-of-care treatment for metastatic bladder cancer is cisplatin-based chemotherapy, but only about 60% of patients qualify for this treatment option and the remaining cohort have few alternatives available. In fact, the only widely considered alternative is immune checkpoint blockades, or immunotherapies, which work to reactivate inhibited functions of immune cells. Unfortunately, these alone have not proven effective against metastatic malignancies. We believe that we can enhance the effects of clinically available immunotherapies with the addition of nanostar mediated photothermal therapy to the primary tumor. In fact, this combination of anti-PD-L1 immune checkpoint blockade and gold nanostar mediated photothermal therapy, henceforth called SYnergistic iMmuno PHOtothermal NanotherapY (SYMPHONY), was previously tested in a pilot study where C57BL/6 mice were injected with MB49 bladder cancer cells at two locations. One of the sites was treated with one of five treatments and the second remained untreated. Both tumor volumes were measured over time and the survival of the mice was also documented. This study resulted in one of the five SYMPHONY mice having complete tumor control after treatment and no other treatment group had this outcome. Upon rechallenge of the same tumor cell line, a tumor did not grow suggesting long-term immunity to this cancer. Along with a proof of concept, these studies were successful in identifying that macrophages and T-cells are associated with the tumor eradication. However, there is still little known about the quantification of the immune response at the distant tumor site after treatment. Our long-term goal is to develop an effective alternative treatment option for patients with metastatic bladder cancer. The overall objective of this application was to quantify the immune response of transgenic mice with fluorescent reporter genes on monocytes, natural killer cells, and dendritic cells undergoing one of four treatments (SYMPHONY, photothermal therapy alone (GNS), immunotherapy alone (anti-PD-L1) or no treatment (control)) as well as identify time points within the week following therapy in which additional studies could be conducted. Our central hypothesis was that mice treated with SYMPHONY would exhibit an elevated immune cell infiltration at the site of the distant tumor within ~48 hours post treatment, and that SYMPHONY will induce a greater immune response at the distant tumor site compared to anti-PD-L1 alone. This hypothesis was tested by implanting a primary flank tumor and a smaller, untreated distant tumor in 14 mice. The distant tumor cells were first stained with a far-red DiD fluorescent dye before injection into the center of a dorsal skinfold window chamber. The primary tumors were treated with one of the four treatment modalities and the window chamber was imaged using intravital microscopy for 7 days after the treatment. From this study, we found that the greatest change in the immune signal for any group occurred in the SYMPHONY group on the day of treatment and this immune signal remained elevated throughout the 7-day imaging period. This change was greater than all other treatment groups, including the anti-PD-L1 group, therefore, we accept our hypothesis. Further work should focus on assessing the immune response in mice on the day of treatment, looking at other immune cell types and by quantifying the effects of laser treatment on this day. It is noted that using the immune signal surrounding the distant tumor to predict an immune response within the tumor requires imaging at intervals more frequent than every 24 hours because of estimated macrophage travel velocity in tissue, where a more suitable frequency would be every 1.5-2 hours.