3D Spheroid Cell Culture Research Articles

Abstract 6281: Differential response of irradiated breast carcinoma cells to DNA-PK inhibition: Spheroid response is governed by cell adhesion effects rather than changes in radiosensitivity

Abstract Agents that increase tumor radiosensitivity are of interest in improving outcomes in radiotherapy (XRT). DNA-PKcs inhibitors lead to radiosensitization and also to alterations in cell adhesion proteins. Using a HER2 positive mammary carcinoma cell line, NT2.5, we investigated the impact of Nu7441, a potent and selective DNA-PKcs inhibitor together with external beam irradiation in both 2D monolayer and 3D spheroid cell culture systems. Colony formation assays were performed for cells irradiated as monolayers and also for cells disaggregated from spheroids. Cells grown in monolayer culture and as spheroids were incubated with Nu7441 (5 µM) for 24 h after different doses of external beam irradiation. In monolayer culture cells, α/β increased from 3.0 ± 0.2 Gy (XRT alone) to 6.9 ± 0.2 Gy when XRT was followed by Nu7441 incubation. Corresponding α/β values for cells obtained by disaggregating treated spheroids were 3.6 ± 0.7 Gy (XRT alone) and 3.5 ± 0.2 Gy (XRT+Nu7441). In contrast to the minimal change in α/β, spheroids survival was highly sensitive to Nu7441 incubation. 21 days after 0, 2, 4, 6, 8, or 10 Gy XRT alone 100, 83, 75, 63, 56, and 31%, respectively, of the irradiated spheroids remained intact; when Nu7441 treatment was involved, 56% remained intact at 2 Gy and 13% at 4 Gy, no spheroids survived to 3 weeks at 6 Gy or more. We also found a progressive increase in fragmentation for spheroids exposed only to Nu7441 (0 Gy): 3/24, 9/24 and 17/24 fragmented after 14, 21 and 28 days of incubation, respectively. The discrepancy between the minimal change in α/β from cells derived from spheroids and the spheroid growth response was not related to poor penetration of Nu7441 since the colony formation assay results for different sizes of spheroids (180 to 400 µm) treated with 4 Gy with or without Nu7441were not significantly different. The results suggest that spheroid response to DNA-PKcs inhibitors is driven by their known inhibition of cell-cell adhesion pathways and potentially less so by radiosensitization. Citation Format: Jing Yu, Ryan Lu, Jessie Nedrow, George Sgouros. Differential response of irradiated breast carcinoma cells to DNA-PK inhibition: Spheroid response is governed by cell adhesion effects rather than changes in radiosensitivity [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6281.

Exploiting CRISPR Cas9 in Three-Dimensional Stem Cell Cultures to Model Disease.

Three-dimensional (3D) cell culture methods have been widely used on a range of cell types, including stem cells to modulate precisely the cellular biophysical and biochemical microenvironment and control various cell signaling cues. As a result, more in vivo-like microenvironments are recapitulated, particularly through the formation of multicellular spheroids and organoids, which may yield more valid mechanisms of disease. Recently, genome-engineering tools such as CRISPR Cas9 have expanded the repertoire of techniques to control gene expression, which complements external signaling cues with intracellular control elements. As a result, the combination of CRISPR Cas9 and 3D cell culture methods enhance our understanding of the molecular mechanisms underpinning several disease phenotypes and may lead to developing new therapeutics that may advance more quickly and effectively into clinical candidates. In addition, using CRISPR Cas9 tools to rescue genes brings us one step closer to its use as a gene therapy tool for various degenerative diseases. Herein, we provide an overview of bridging of CRISPR Cas9 genome editing with 3D spheroid and organoid cell culture to better understand disease progression in both patient and non-patient derived cells, and we address potential remaining gaps that must be overcome to gain widespread use.

Generation of 3D Tumor Spheroids with Encapsulating Basement Membranes for Invasion Studies

In the past, in vitro studies of invasion and tumor progression were performed primarily using cancer cells cultured on a flat, two‐dimensional (2D) surface in a monolayer. In recent years, however, many studies have demonstrated differences in cell signaling and cell migration between 2D and 3D cell cultures. Traditional 2D monolayer cancer cell invasion models do not fully recapitulate 3D cell‐to‐cell and cell−to−extracellular matrix interactions that in vivo models can provide. Moreover, although in vivo animal models are irreplaceable for studying tumor biology and metastasis, they are costly, time‐consuming, and impractical for answering preliminary questions. Thus, emergent and evolving 3D spheroid cell culture models have changed the way we study tumors and their interactions with their surrounding extracellular matrix. In the case of breast cancer, metastasis of breast cancer tumors results in high mortality rates, and thus development of robust cell culture models that are reproducible and practical for studying breast cancer progression is important for ultimately developing preventatives for cancer metastasis. This article provides a set of protocols for generating uniform spheroids with a thin sheet of basement membrane for studying the initial invasion of mammary epithelial cells into a surrounding collagen‐rich extracellular matrix. Details are provided for generating 3D spheroids with a basement membrane, polymerizing collagen I, embedding the spheroids in the 3D collagen gel, and immunostaining the spheroids for invasion studies. Published 2020. U.S. Government. Basic Protocol 1: Growth of uniformly sized tumor spheroids with an encapsulating basement membrane Basic Protocol 2: Polymerization and embedding of tumor spheroids in a 3D type I collagen gel Alternate Protocol: Embedding of tumor spheroids in collagen gels using a sandwich method Basic Protocol 3: Fixing and immunostaining of tumor spheroids embedded in 3D collagen gels

Isolation of cancer stem-like cells from hepatocellular carcinoma cell line HepG2 by methods of magnetic-activated cell sorting, spheroid culture, and anti-tumor drug-resistant selection: A primary evaluation

Introduction: Recently reported data have suggested that only a small subset of cancer cells possess the capability to initiate malignancies. These observations were based on investigation of cells within the primary tumors displaying a distinct surface marker pattern. CD133 marker is a putative hematopoietic and neuronal stem cell marker, which is also considered to be a tumorigenic marker in brain, prostate and liver. Recent studies have shown that a small population of CD133-positive cells, indeed, exists in human hepatocellular carcinoma (HCC) cell lines and primary HCC tissues. This study was aimed at isolating the cancer stem-like cells from hepatocellular carcinoma cell line HepG2 using three different methods: magnetic-activated cell sorting (MACS), spheroid culture (SC), and anti-tumor drug (ATD) resistant selection.
 Methods: HepG2 hepatocellular carcinoma cells were expanded to yield enough cells that could be used to isolate cancer stem-like cells by these three methods. For MACS, cancer stem-like cells were sorted using anti-CD133 monoclonal antibody. For the second method, cancer stem-like cells were enriched by selection of anti-tumor drug resistance property. Lastly, for the third method, three-dimensional (3D) culture was used to enrich for the cancer stem-like cells. The cells obtained by the three methods were expanded to obtain an adequate number of cells for confirmation of CD133 expression.
 Results: The expression of CD133+ cells in the three methods was found to be different. In the MACS method, the expanded CD133+ sorted cells cultured through 2 passages only contained 0.40 % CD133+ cells. In the 3D spheroid cell culture, of the population of cells there were 38.39 % that were CD133+ cells. Lastly, in the anti-tumor drug (doxorubicin at 150 nM) resistant selection, 66.22 % were CD133+ cells.
 Conclusion: This study shows that isolation of HepG2 derived CD133+ population by culture with doxorubicin (150 nM) yields the highest efficiency and purity of the 3 methods studied.

Probing the Ultrastructure of Spheroids and Their Uptake of Magnetic Nanoparticles by FIB–SEM

AbstractSpheroids are 3D cellular systems largely adopted as model for high‐throughput screening of molecules and diagnostics tools. Furthermore, those cellular platforms also represent a model for testing new delivery carries for selective targeting. The coupling between the 3D cell environment and the nanovectors can be explored at the macroscale by optical microscopy. However, the nanomaterial‐cell interplay finds major action at the single cell and extracellular matrix level with nanoscale interactions. Electron microscopy offers the resolution to investigate those interactions; however, the specimen preparation finds major drawbacks in its operation time and preciseness. In this context, focused ion beam and scanning electron microscopy (FIB–SEM) allows for fast processing and high resolution of the cell‐nanomaterial interface. Here, in fact, a novel approach is shown to prepare large‐area 3D spheroid cell culture specimens for FIB–SEM. Sectioning procedures are explored to preserve the peculiar structure of spheroids and their interaction with magnetic nanovectors. The results pave the way for advanced investigations of 3D cellular systems with nano and micromaterials relevant to tissue engineering, bioelectronics, and diagnostics.

Abstract 1927: High-throughput cell line panel drug screening in organoids and 3D systems

Abstract Cell panel screening of cancer lines grown in standard 2D conditions is a well-established component of the drug discovery toolbox. A sufficiently large cell line panel, reflecting the molecular heterogeneity within a cancer type/sub-type, is required to detect correlations with robust statistical power that aid biomarker identification and patient stratification. However, the heterogenous exposure of tumor cells to nutrients, oxygen and other physical or chemical stresses found in three-dimensional solid tumors also has a role to play in patient response and this is not well mimicked in 2D monolayer cell cultures. To meet the need for high-throughput cell-panel screening in more complex culture systems, we have developed 3D cell-based screens to more closely model the complex physiological environment found in tumors. We have characterised our OncoSignature panel of 300 cell lines for growth as spheroids to produce a 200 strong panel of spheroid forming lines. Using our high-throughput platform to compare drug activity in 2D and 3D cultures, we have identified clear differentials for some compounds in single agent and drug combination screens. For example, MEK and EGFR inhibitors have significantly higher activity in 3D cultures than 2D cultures, with a greater than 10-fold shift in EC50 values. These results were validated in 3D soft agar assays, with similar compound potencies being observed in the HTS spheroid assay and the lower throughput soft-agar assay. We have further extended our 3D screening into organoid cultures. Organoid cultures, with increased complexity in terms of structure and cell heterogeneity compared to spheroids, have historically been challenging to use in high-throughput screening. However, our initial results show encouragingly robust data, with compound activity that is congruent with the genetic characteristics of the organoids. Finally, we used our integrated screening platform to evaluate the power of CRISPR approaches to examine genetic dependencies in KRAS mutant cells in 2D, 3D spheroid and organoid cell cultures. Pooled, next-generation sequencing-linked CRISPRko allows an alternative and complementary genomics approach to arrayed cell panel screening, providing a powerful and robust target identification and validation strategy. Overall, Horizon’s 3D screening platforms will enable large scale interrogation of both drug and gene interactions in more complex cell culture systems. Citation Format: Tim M. Scales, Anett Rada-Kovacs, Helen N. Pemberton, Ceri M. Wiggins, Nicola J. McCarthy, Annette S. Little, David A. Sorrell. High-throughput cell line panel drug screening in organoids and 3D systems [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1927.

Toxicity and anti-prolific properties of Xysmalobium undulatum water extract during short-term exposure to two-dimensional and three-dimensional spheroid cell cultures

Xysmalobium undulatum (Uzara) is one of the most widely used indigenous traditional herbal remedies in Southern Africa. Commercially available Uzara plant material was used to prepare a crude aqueous extract, of which the toxicity potential was investigated in the hepatic HepG2/C3A cell line in both traditional two-dimensional (2D) and rotating three-dimensional (3D) spheroid cell cultures. These cultures were treated over a period of 4 days at concentrations of 200, 350, 500, and 750 mg/kg plant extract to protein content. Basic physiological parameters of the cell cultures were measured during exposure, including cell proliferation, glucose uptake, intracellular adenosine triphosphate levels, and adenylate kinase release. The results indicated that all physiological parameters monitored were affected in a dose dependent manner, with the highest concentration of Uzara crude water extract (750 mg/kg) resulting in toxicity. Anti-proliferating effects of Uzara crude water extract were observed in both the 2D and 3D cell cultures, with the most pronounced effects at concentrations of 350, 500, and 750 mg/kg. Discrepancies between results obtained from the 2D and 3D cell culture models may be attributed to the type of repair system that is initiated upon exposure, depending on where cells are within the cell cycle. DNA repair systems differ in cells within the G1 phase and non-diving cells, (i.e. cells found predominantly in in vitro 3D and the in vivo situation).

A Caspase-3 Reporter for Fluorescence Lifetime Imaging of Single-Cell Apoptosis.

Fluorescence lifetime imaging (FLIM) is a powerful imaging modality used to gather fluorescent reporter data independent of intracellular reporter intensity or imaging depth. We applied this technique to image real-time activation of a reporter for the proteolytic enzyme, caspase-3, in response to apoptotic cell death. This caspase-3 reporter activity provides valuable insight into cancer cell responsiveness to therapy and overall viability at a single-cell scale. Cleavage of a aspartate-glutamate-valine-aspartate (DEVD) linkage sequence alters Förster resonance energy transfer (FRET) within the reporter, affecting its lifetime. Cellular apoptosis was quantified in multiple environments ranging from 2D flat and 3D spheroid cell culture systems to in vivo murine mammary tumor xenografts. We evaluated cell-by-cell apoptotic responses to multiple pharmacological and genetic methods of interest involved in cancer cell death. Within this article, we describe methods for measuring caspase-3 activation at single-cell resolution in various complex environments using FLIM.

Abstract B35: An innovative in vivo model of metastasizing prostate cancer using orthotopic xenografts

Abstract Introduction: In this study, we aimed to develop a versatile in vivo model of prostate cancer using orthotopic xenografts, which adequately represents intraprostatic tumor growth as well as the natural routes of metastatic spread. Materials and Methods: 5x105 VCaP-, LuCaP136-, and LuCaP147 cells were injected into the prostate of male CB17-SCID mice (n=8 for each cell line; VCaP cultured as monolayer, LuCaP136 and LuCaP147 as three-dimensional spheroid culture). During 12 weeks of follow-up, orthotopic tumor growth and the development of metastases was monitored by repetitive serum-PSA measurements and imaging studies (ultrasonography, CT, MRI). At autopsy, primary tumors and metastases were harvested and examined by conventional histology (H&E) and immunohistochemistry (CK5, CK8, AMACR, AR, Ki67, ERG, PSA). From the results of the imaging studies and PSA measurements, tumor volume doubling time, tumor-specific growth rate, and PSA-density were calculated for each cell line. Results: All 24 mice developed orthotopic tumors, whose growth could be reliably monitored by ultrasonography, CT, MRI, and serum-PSA measurements. 4 animals died during follow-up (1 in the VCaP group, 1 in the LuCaP136 group, 2 in the LuCaP147 group). Mean PSA-density was 433.9 ng/ml per ml tumor in the VCaP group, 6.5 ng/ml per ml tumor in the LuCaP136 group, and 11.2 ng/ml per ml tumor in the LuCaP147 group. Tumor-specific growth rate and tumor volume doubling time were 3.87% per day and 21.24 days in the VCaP group, 3.11% and 27.57 days in the LuCaP136 group, and 4.47% and 16.2 days in the LuCaP147 group, respectively. In up to 100% of animals, lymph node metastases could be detected after 12 weeks (5/7 in the VCaP group, 6/7 in the LuCaP136 group, 6/6 in the LuCaP147 group). These could also be visualized by ultrasonography and MRI. Immunohistochemistry showed positive CK8, AR, and AMACR as well as negative CK5 reactions in all tumors. ERG-straining was positive in VCaP and negative in both LuCaP tumors, Ki67 proliferation indices were >90% in all groups. Conclusions: By using different monolayer as well as 3D spheroid cell cultures in an orthotopic xenograft model, we could establish an innovative, versatile in vivo model of prostate cancer, which enables the study of both intraprostatic tumor growth as well as metastatic spread to regional lymph nodes. Citation Format: Johannes Linxweiler, Christina Körbel, Andreas Müller, Markus Hammer, Michael Stöckle, Kerstin Junker, Michael D. Menger. An innovative in vivo model of metastasizing prostate cancer using orthotopic xenografts [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr B35.

Utility of a 3D spheroid cell culture system in neuroendocrine tumors

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

A novel mouse model of human prostate cancer to study intraprostatic tumor growth and the development of lymph node metastases

In this study, we aimed to establish a versatile in vivo model of prostate cancer, which adequately mimics intraprostatic tumor growth, and the natural routes of metastatic spread. In addition, we analyzed the capability of high-resolution ultrasonography (hrUS), in vivo micro-CT (μCT), and 9.4T MRI to monitor tumor growth and the development of lymph node metastases. A total of 5 × 105 VCaP cells or 5 × 105 cells of LuCaP136- or LuCaP147 spheroids were injected into the prostate of male CB17-SCID mice (n = 8 for each cell type). During 12 weeks of follow-up, orthotopic tumor growth, and metastatic spread were monitored by repetitive serum-PSA measurements and imaging studies including hrUS, μCT, and 9.4T MRI. At autopsy, primary tumors and metastases were harvested and examined by histology and immunohistochemistry (CK5, CK8, AMACR, AR, Ki67, ERG, and PSA). From imaging results and PSA-measurements, tumor volume doubling time, tumor-specific growth rate, and PSA-density were calculated. All 24 mice developed orthotopic tumors. The tumor growth could be reliably monitored by a combination of hrUS, μCT, MRI, and serum-PSA measurements. In most animals, lymph node metastases could be detected after 12 weeks, which could also be well visualized by hrUS, and MRI. Immunohistochemistry showed positive signals for CK8, AMACR, and AR in all xenograft types. CK5 was negative in VCaP- and focally positive in LuCaP136- and LuCaP147-xenografts. ERG was positive in VCaP- and negative in LuCaP136- and LuCaP147-xenografts. Tumor volume doubling times and tumor-specific growth rates were 21.2 days and 3.9 %/day for VCaP-, 27.6 days and 3.1 %/day for LuCaP136- and 16.2 days and 4.5 %/day for LuCaP147-xenografts, respectively. PSA-densities were 433.9 ng/mL per milliliter tumor for VCaP-, 6.5 ng/mL per milliliter tumor for LuCaP136-, and 11.2 ng/mL per milliliter tumor for LuCaP147-xenografts. By using different monolayer and 3D spheroid cell cultures in an orthotopic xenograft model, we established an innovative, versatile in vivo model of prostate cancer, which enables the study of both intraprostatic tumor growth as well as metastatic spread to regional lymph nodes. HrUS and MRI are feasible tools to monitor tumor growth and the development of lymph node metastases while these cannot be visualized by μCT.

Using 3D spheroid cell cultures to investigate photodynamic therapy in colorectal cancer

Using 3D spheroid cell cultures to investigate photodynamic therapy in colorectal cancer

Using 3D spheroid cell cultures to investigate photodynamic therapy in colorectal cancer

Using 3D spheroid cell cultures to investigate photodynamic therapy in colorectal cancer

Cell-free DNA in a three-dimensional spheroid cell culture model: A preliminary study

BackgroundInvestigating the biological functions of cell-free DNA (cfDNA) is limited by the interference of vast numbers of putative sources and causes of DNA release into circulation. Utilization of three-dimensional (3D) spheroid cell cultures, models with characteristics closer to the in vivo state, may be of significant benefit for cfDNA research. MethodsCfDNA was isolated from the growth medium of C3A spheroid cultures in rotating bioreactors during both normal growth and treatment with acetaminophen. Spheroid growth was monitored via planimetry, lactate dehydrogenase activity and glucose consumption and was related to isolated cfDNA characteristics. ResultsChanges in spheroid growth and stability were effectively mirrored by cfDNA characteristics. CfDNA characteristics correlated with that of previous two-dimensional (2D) cell culture and human plasma research. Conclusions3D spheroid cultures can serve as effective, simplified in vivo-simulating “closed-circuit” models since putative sources of cfDNA are limited to only the targeted cells. In addition, cfDNA can also serve as an alternative or auxiliary marker for tracking spheroid growth, development and culture stability. Biological significance3D cell cultures can be used to translate “closed-circuit” in vitro model research into data that is relevant for in vivo studies and clinical applications. In turn, the utilization of cfDNA during 3D culture research can optimize sample collection without affecting the stability of the growth environment. Combining 3D culture and cfDNA research could, therefore, optimize both research fields.

Efficacy, maximal tolerated dose, and toxicokinetics of TTC-352 in rats and dogs, a partial ER agonist for metastatic ER+ breast cancer.

e14090 Background: The high prevalence of treatment resistance for estrogen receptor positive (ER+) breast cancer cause more deaths than all other breast cancers, despite the availability of endocrine therapeutics including selective ER downregulators (SERDs). Before tamoxifen, high dose estradiol (E2) delivered clinical efficacy slightly superior to tamoxifen. While recent clinical trials have shown efficacy of low dose E2, unacceptable side effects including vaginal bleeding, endometrial hypertrophy, and the negative perceptions of both patients and physicians limit acceptance. In preclinical models, tamoxifen resistant (TR) breast cancer is sensitive to treatment by E2. TTC-352 is an orally bioavailable selective human ERα partial agonist (ShERPA) designed to mimic E2 in causing tumor regression of TR breast cancer xenografts without uterine proliferation caused by E2 and tamoxifen. Methods: The published preclinical efficacy studies were extended to multiple TR ER+ cell lines in 3D spheroid cell cultures comparing to E2 and the SERD GDC0810. The maximum tolerated dose (MTD) was determined in Sprague-Dawley rats at: 200, 300, 600, 1000 and 2000 mg/kg by oral gavage (N = 3). Animals were observed for 7 days prior to necropsy. A single MTD range finding study was performed in dogs at: 50, 100, and 200 mg/kg TTC-352, administered orally in gelatin capsules. Based on these results, a 7-day repeated dose studies were completed at 30, 100, 300 and 1000 mg/kg/day in rats (3/sex/dose) and 15, 75, and 150 mg/kg (2/sex/dose) in dogs. Results: Growth of three TR ER+ breast cancer cell cultures in 3D was inhibited by TTC-352, which mimicked E2 and was equivalent to GDC0810. In female rats MTD was 1000 mg/kg and TTC-352 was well tolerated following a single oral dose of 200, 300, 600 mg/kg. The oral administration of TTC-352 at doses of 30, 100, and 300 mg/kg/day in rats (both sexes) and 15, 75 or 150 mg/kg/day in dogs (both sexes) for seven days was generally well tolerated. Conclusions: TTC-352 has demonstrated efficacy in preclinical models of TR breast cancer. Completed rat and dog studies indicated favorable tolerability and rapid absorption up to 300 mg/kg/day in rats and 150 mg/kg/day in dogs.

Evaluation of cell-surface interaction using a 3D spheroid cell culture model on artificial extracellular matrices

Since decades, cell-surface interactions are studied in 2D cell culture approaches, but cells organized in 3D (spheroids) reflect the normal situation of cells in tissues much better due to intense cell-cell-contacts. Accordingly, this study aimed to prove, if spheroids could be used to study cell-surface interaction.Spheroids consisting of fibroblasts and/or osteoblasts were seeded on artificial extracellular matrices. Here, non-sulfated hyaluronan as a biological relevant compound of the extracellular matrix was chemically sulfated to different extents and co-fibrillised with collagen. The changes of the spheroid diameters and the migration distance of outgrown cells after seeding on the matrices were used as parameters to evaluate cell-surface interaction quantitatively.Fibroblast-based spheroids reacted in the initial phase of adhesion with different spheroid sizes on the contact with the matrices. In contrast, the reaction of osteoblasts was more pronounced at later time points exhibiting a decrease of the size of the spheroids with increasing sulfation degree of the matrix. The migration of the cells was impaired by increasing sulfation degree, which might be caused by an increased expression of focal adhesion relevant proteins. In summary, spheroids can be used in cell-surface interaction studies and additional analytical tools could be implemented.

Abstract 3902: Novel selective estrogen receptor downregulators developed using endocrine-independent breast cancer cell lines

Abstract Approximately 70% of breast cancer patients are estrogen receptor positive (ER+). Aromatase inhibitors and the selective estrogen receptor modulator (SERM), tamoxifen, are the first line treatments for these patients; however, almost 50% of patients either do not respond or acquire resistance. Multiple mechanisms, including mutations of the ESR1 gene, contribute to resistance via ligand-independent constitutive activation of ER. Selective estrogen down-regulators (SERDs) that block ligand-dependent and independent ER signaling by ablation of ER, offer a therapeutic approach to treatment-resistant, advanced stage and early stage ER+ breast cancer. Therapeutic use of the first generation SERD, fulvestrant (Faslodex), has largely remained 2nd and 3rd line, because of poor physiochemical/pharmacokinetic properties. Novel benzothiophene based SERDs were designed, synthesized, and optimized and assayed in three tamoxifen-resistant (TR), endocrine-independent ER+ MCF-7 and T-47D cell lines. Cell viability, ERE-luciferase response, and ER degradation was measured and compared to parent endocrine-dependent MCF-7 and T-47D cell lines in 2D and/or 3D spheroid cell cultures and compared to SERDs, fulvestrant and GDC-0810. Pharmacokinetic analysis was used to select novel SERDs for xenograft studies. Citation Format: Rui Xiong, Jiong Zhao, Lauren Gutgesell, Debra Tonetti, Gregory Thatcher. Novel selective estrogen receptor downregulators developed using endocrine-independent breast cancer cell lines. [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 3902.

Intratracheal Administration of Hyaluronan-Cisplatin Conjugate Nanoparticles Significantly Attenuates Lung Cancer Growth in Mice.

To determine aerosol administration capability and therapeutic efficacy of the new formulation of hyaluronan cisplatin conjugates, HylaPlat™ (HA-Pt), for lung cancer treatment. In vitro formulation stability test, 2D and 3D spheroid cell culture and in vivo efficacy studies using mouse orthotopic allograft models were conducted. The HA-Pt effectively attenuated cell growth in 2D and 3D cultures with IC50 of 2.62 and 5.36μM, respectively, which were comparable to those with unconjugated control cisplatin-dependent growth inhibition (IC50 1.64 and 4.63μM, respectively). A single dose of either 7.5 or 15mg/kg HA-Pt (cisplatin equivalent) by intratracheal aerosol spray 7days after Lewis lung carcinoma (LLC) cell inoculation markedly inhibited growth of LLC allografts in mouse lungs and resulted in a 90 or 94% reduction of tumor nodule numbers, respectively, as compared to those from the PBS control. Cancer stem cells and cisplatin resistant cells marker, CD44 expression decreased in the tumor nodules of the HA-Pt but not in those of cisplatin treated groups. The current study suggests that an intratracheal aerosol administration of the HA-Pt nanoparticles offers an effective strategy for lung cancer treatment and this treatment may induce only limited cisplatin resistance.

Calcium Electroporation: Evidence for Differential Effects in Normal and Malignant Cell Lines, Evaluated in a 3D Spheroid Model

BackgroundCalcium electroporation describes the use of high voltage electric pulses to introduce supraphysiological calcium concentrations into cells. This promising method is currently in clinical trial as an anti-cancer treatment. One very important issue is the relation between tumor cell kill efficacy–and normal cell sensitivity.MethodsUsing a 3D spheroid cell culture model we have tested the effect of calcium electroporation and electrochemotherapy using bleomycin on three different human cancer cell lines: a colorectal adenocarcinoma (HT29), a bladder transitional cell carcinoma (SW780), and a breast adenocarcinoma (MDA-MB231), as well as on primary normal human dermal fibroblasts (HDF-n).ResultsThe results showed a clear reduction in spheroid size in all three cancer cell spheroids three days after treatment with respectively calcium electroporation (p<0.0001) or electrochemotherapy using bleomycin (p<0.0001). Strikingly, the size of normal fibroblast spheroids was neither affected after calcium electroporation nor electrochemotherapy using bleomycin, indicating that calcium electroporation, like electrochemotherapy, will have limited adverse effects on the surrounding normal tissue when treating with calcium electroporation. The intracellular ATP level, which has previously been shown to be depleted after calcium electroporation, was measured in the spheroids after treatment. The results showed a dramatic decrease in the intracellular ATP level (p<0.01) in all four spheroid types—malignant as well as normal.ConclusionIn conclusion, calcium electroporation seems to be more effective in inducing cell death in cancer cell spheroids than in a normal fibroblast spheroid, even though intracellular ATP level is depleted in all spheroid types after treatment. These results may indicate an important therapeutic window for this therapy; although further studies are needed in vivo and in patients to investigate the effect of calcium electroporation on surrounding normal tissue when treating tumors.

Abstract 5533: A local chemotherapy with hyaluronan-cisplatin conjugate significantly attenuates growth of lung adenocarcinoma xenografts in mouse model

Abstract Nanoparticle-based chemotherapy, while promising, remains clinically unsuccessful, mainly due to a lack of targeted delivery methods of the therapeutics into cancer tissues and the side effect of chemotherapeutics. We have demonstrated that the nanoparticle formulation with hyaluronan-cisplatin conjugates (HylaPlat) is suggested to be an effective chemotherapeutic delivery method in breast cancer mouse models (Cai, et al., J Surg Res., 2008; Cai, et al., Ther Deliv, 2011). The objectives of the present study were to examine the growth inhibition efficacy of HylaPlat formulation on lung adenocarcinoma cells in cell culture and to examine the therapeutic efficiency of the local administration of HylaPlat on lung adenocarcinoma in mice. Effect of the HylaPlat on the growth of lung carcinoma was evaluated using Lewis Lung carcinoma (LLC) cells in 2D culture and 3D spheroid cell culture, as well as, orthotopic autografts in C57BL/6 mice lungs. Cell culture studies clarified that the HylaPlat effectively attenuated cell growth in 2D and 3D spheroid culture with IC50 of 0.35μM and 1.35 μM, respectively; whereas control cisplatin-dependent growth inhibition was achieved with several fold higher concentrations (IC50 1.64 and 3.6 μM, respectively). The 3D spheroid cell culture study also revealed that the treatment with HylaPlat induced apoptosis in the cells located on the peripheral area of the spheroid first, this effect lasted for several days. A single intratracheal administration of 7.5mg/kg HylaPlat (1mg cisplatin equivalent/kg) seven days after LLC cell inoculation almost completely inhibited growth of LLC autografts in the mouse lungs. Histological analysis of dissected lungs revealed that a small number of microscopic tumor nodules were detected in the treated mouse lungs, whereas several large tumors were detected in the untreated control mouse lungs. Normal lung architectures of the trachea, bronchioles and alveoli were maintained in the treated mice although small inflammation spots can be detected at peripheral areas. Apoptotic index was significantly higher in the treated tumors than PBS treated control tumors, suggesting that cisplatin was successfully delivered to the tumor tissues by nanoparticle formulated HylaPlat and caused apoptosis of tumor cells. The pharmacokinetics of cisplatin 14 days after intratracheal administration of HylaPlat is under investigation. Taken together, the current study suggests that an intratracheal administration of HylaPlat nanoparticles offer an effective strategy for lung cancer treatment. This work was supported by the Kansas State University Johnson Cancer Research Center, Kansas Bioscience Authority Collaborative Cancer Research grant, 1R01CA173292 (LF) and American Cancer Society RSG-08-133-01-CDD (LF). Citation Format: Susumu Ishiguro, Deepthi Uppalapati, Shuang Cai, Katie Turner, Jacob Hodge, Laird Forest, Masaaki Tamura. A local chemotherapy with hyaluronan-cisplatin conjugate significantly attenuates growth of lung adenocarcinoma xenografts in mouse model. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5533. doi:10.1158/1538-7445.AM2015-5533