Cancer cells mimic in vivo spatial-temporal cell-cycle phase distribution and chemosensitivity in 3-dimensional Gelfoam® histoculture but not 2-dimensional culture as visualized with real-time FUCCI imaging

Partial Alleviation of Homologous Superinfection Exclusion of SeMNPV Latently Infected Cells by G1 Phase Infection and G2/M Phase Arrest

Viral infection can regulate the cell cycle, thereby promoting viral replication. Hijacking and altering the cell cycle are important for the virus to establish and maintain a latent infection. Previously, Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV)-latently infected P8-Se301-C1 cells, which grew more slowly than Se301 cells and interfered with homologous SeMNNPV superinfection, were established. However, the effects of latent and superinfection with baculoviruses on cell cycle progression remain unknown. In this study, the cell cycle profiles of P8-Se301-C1 cells and SeMNPV or Autographa californica multiple nucleopolyhedrovirus (AcMNPV)-infected P8-Se301-C1 cells were characterized by flow cytometry. The results showed that replication-related genes MCM4, PCNA, and BAF were down-regulated (p < 0.05) in P8-Se301-C1 cells, and the S phase of P8-Se301-C1 cells was longer than that of Se301 cells. P8-Se301-C1 cells infected with SeMNPV did not arrest in the G2/M phase or affect the expression of Cyclin B and cyclin-dependent kinase 1 (CDK1). Furthermore, when P8-Se301-C1 cells were infected with SeMNPV after synchronized treatment with hydroxyurea and nocodazole, light microscopy and qRT-PCR analysis showed that, compared with unsynchronized cells and S and G2/M phase cells, SeMNPV-infected P8-Se301-C1 cells in G1 phase induced G2/M phase arrest, and the amount of virus adsorption and intracellular viral DNA replication were significantly increased (p < 0.05). In addition, budded virus (BV) production and occlusion body (OB)-containing cells were both increased at 120 h post-infection (p < 0.05). The expression of Cyclin B and CDK1 was significantly down-regulated at 48 h post-infection (p < 0.05). Finally, the arrest of SeMNPV-infected G1 phase cells in the G2/M phase increased BV production (p < 0.05) and the number of OB-containing cells. In conclusion, G1 phase infection and G2/M arrest are favorable to SeMNPV proliferation in P8-Se301-C1 cells, thereby alleviating the homologous superinfection exclusion. The results contribute to a better understanding of the relationship between baculoviruses and insect cell cycle progression and regulation.

Escin-sorafenib synergy up-regulates LC3-II and p62 to induce apoptosis in hepatocellular carcinoma cells

INTRODUCTION

Hepatocellular carcinoma (HCC) is a common solid cancer and the leading cause of cancer deaths worldwide. Sorafenib is the first drug used to treat HCC but its effectiveness needs to be improved, and it is important to find ways to treat cancer that combine sorafenib with other drugs. Synergistic therapies lower effective drug doses and side effects while enhancing the anticancer effect.

PURPOSE

In the present study, the therapeutic potential of sorafenib in combination with escin and its underlying mechanism in targeting liver cancer has been established.

STUDY DESIGN/METHODS

The IC50 of sorafenib and escin against HepG2, PLC/PRF5 and Huh7 cell lines were determined using MTT assay. The combination index, dose reduction index, isobologram and concentrations producing synergy were evaluated using the Chou-Talaly algorithm. The sub-effective concentration of sorafenib and escin was selected to analyze cytotoxic synergistic potential. Cellular ROS, mitochondrial membrane potential, annexin V and cell cycle were evaluated using a flow-cytometer, and autophagy biomarkers were determined using western blotting. Moreover, autophagy was knocked down using ATG5 siRNA to confirm its role. A DEN-induced liver cancer rat model was developed to check the synergy of sorafenib and escin.

RESULTS

Different concentrations of escin reduced the IC50 of sorafenib in HepG2, PLC/PRF5 and Huh7 cell lines. Chou-Talaly algorithm determined cytotoxic synergistic concentrations of sorafenib and escin in these cell lines. Mechanistically, this combination over-expressed p62 and LC-II, reflecting autophagy block and induced late apoptosis, further reconfirmed by ATG5 knockdown. Sorafenib and escin combination  reduced HCC serum biomarker α-feto protein (α-FP) by 1.5 folds. This combination restricted liver weight, tumor number and size, also, conserved morphological features of liver cells. The combination selectively targeted the G0 /G1 phase of cancer cells.

CONCLUSION

Escin and sorafenib combination potentially up-regulates p62 to block autophagy to induce late apoptosis in liver cancer cells.

Gossypol synergises antiproliferative effect of sorafenib in metastatic lung cancer cells following Chou-Talalay algorithm

Combination therapy has been proposed as a promising approach for lung cancer treatment, as it can enhance anticancer efficacy, and reduce dosages and adverse effects. This study aimed to explore the therapeutic potential of gossypol, a natural polyphenolic compound with sorafenib for treating lung cancer cells and elucidating its mechanism of action. The MTT assay was utilized to determine the IC50 of sorafenib and gossypol against A549 and NCI H460 cell lines. The Chou-Talaly algorithm was employed to determine the combination index (CI). A sub-effective concentration of sorafenib and gossypol was chosen to investigate the possibility of cytotoxic synergy. Autophagy biomarkers were identified using Western blotting, and the function of autophagy was determined using ATG5 siRNA. Results show that IC50 of sorafenib significantly reduced in A549 and NCI H460 cells when co-treated with gossypol. The combination treatment showed a synergistic cytotoxic effect against tested cell lines. The Chou-Talaly algorithm confirmed sorafenib's dose reduction index (DRI) up to 3.86. In A549 cells, combination treatment down-regulated p62 and up-regulated LC3-II, indicating the initiation of autophagy-dependent cytotoxicity. This was further confirmed by siRNA ATG5 knockdown. Additionally, the combination treatment exclusively targeted G0/G1 phase cancer cells. In conclusion, the combination of gossypol and sorafenib shows a synergistic increase in the cytotoxic effect by promoting autophagy and apoptosis.

Escin enhanced the efficacy of sorafenib by autophagy-mediated apoptosis in lung cancer cells

Combining anti-cancer drugs has been exploited as promising treatment strategy to target lung cancer. Synergistic chemotherapies increase anti-cancer effect and reduce effective drug doses and side effects. In this study, therapeutic potential of escin in combination with sorafenib has been explored. 3-(4,5-Dimethylthiazol-2-yl)-2 5-diphenyltetrazolium bromide assay was used to calculate IC50 values. The synergy was evaluated using Chou-Talaly algorithm. Cellular reactive oxygen species, mitochondrial membrane potential, annexin V, and cell-cycle studies were done by flow-cytometer, and autophagy biomarkers expression were determined using western blotting. Moreover, autophagy was knocked down using ATG5 siRNA to confirm its role, diethylnitrosamine-induced lung cancer model was used to check the synergy of sorafenib/escin. Escin significantly reduced the IC50 of sorafenib in A549 and NCIH460 cells. The combination of sorafenib/escin produced a 2.95 and 5.45 dose reduction index for sorafenib in A549 and NCI-H460 cells. The combination of over-expressed p62 and LC3-II reflects autophagy block-mediated late apoptosis. This phenomenon was reconfirmed by ATG5 knockdown. This combination also selectively targeted G0/G1 phase of cancer cells. In in vivo study, the combination reduced tumour load and lower elevated serum biochemical parameters. The combination of sorafenib/escin synergistically inhibits autophagy to induce late apoptosis in lung cancer cells' G0/G1 phase.

High density lipoprotein nanoparticle as delivery system for radio-sensitising miRNA: An investigation in 2D/3D head and neck cancer models

Radiotherapy is one of the main treatment options for head and neck cancer patients. However, its clinical efficacy is hindered by both radiation induced side effects and radio-resistance. Radio-sensitising approaches with acceptable toxicity are being actively investigated. Among these, RNA therapeutics have great potentials as radio-sensitisers owing to their ability to target pathways specific to radio-resistance. However, their clinical translation is challenging due to delivery issues. Herein, we report the application of high-density lipoprotein nanoparticle (HDL NPs) as a biocompatible delivery system for a well-established radio-sensitising RNA, miR-34a. A simple/fast microfluidic based technique was used to prepare miR-34a-HDL NPs. Profiling of the radiation response in the UM-SCC-1 head and neck cancer cell line confirmed reduced metabolic activity and increased radiation induced apoptosis upon treatment with miR-34a-HDL NPs. The radio-sensitising properties of miR-34a-HDL NPs were further confirmed in a more biologically relevant co-culture spheroid model of head and neck cancer. Increased apoptotic activity and disrupted cell cycle were induced by miR-34a delivered by HDL NPs. The enhanced radio-biologic effects observed in both 2D and 3D models confirmed the utility of HDL NPs as an efficient delivery system for radio-sensitising RNA.

3D modeling in cancer studies

The tumor microenvironment contributes significantly to tumor initiation, progression, and resistance to chemotherapy. Much of our understanding of the tumor and its microenvironment is developed using various methods of cell culture. Throughout the last two decades, research has increasingly shown that 3D cell culture systems can remarkably recapitulate the complexity of tumor architecture and physiology compared to traditional 2D models. Unlike the flat culture system, these novel models enabled more cell-cell and cell-extracellular matrix interactions. By mimicking in vivo microenvironment, 3D culture systems promise to become accurate tools ready to be used in diagnosis, drug screening, and personalized medicine. In this review, we discussed the importance of 3D culture in simulating the tumor microenvironment and focused on the effects of cancer cell-microenvironment interactions on cancer behavior, resistance, proliferation, and metastasis. Finally, we assessed the role of 3D cell culture systems in the contexts of drug screening. 2D culture system is used to study cancer cell growth, progression, behavior, and drug response. It provides contact between cells and supports paracrine crosstalk between host cells and cancer cells. However, this system fails to simulate the architecture and the physiological aspects of in vivo tumor microenvironment due to the absence of cell-cell/ cell-ECM interactions as well as unlimited access to O₂ and nutrients, and the absence of tumor heterogeneity. Recently advanced research has led researchers to generate 3D culture system that can better recapitulate the in vivo environment by providing hypoxic medium, facilitating cell-cell and cell-ECM, interactions, and recapitulating heterogeneity of the tumor. Several approaches are used to maintain and expand cancer cells in 3D culture systems such as tumor spheroids (cell aggregate that mimics the in vivo growth of tumor cells), scaffold-based approaches, bioreactors, microfluidic derives, and organoids. 3D systems are currently used for disease modeling and pre-clinical drug testing.

FUCCI-Red: a single-color cell cycle indicator for fluorescence lifetime imaging

The phase of the cell cycle determines numerous aspects of cancer cell behaviour including invasiveness, ability to migrate and responsiveness to cytotoxic drugs. To non-invasively monitor progression of cell cycle in vivo, a family of genetically encoded fluorescent indicators, FUCCI (fluorescent ubiquitination-based cell cycle indicator), has been developed. Existing versions of FUCCI are based on fluorescent proteins of two or more different colors fused to cell-cycle-dependent degradation motifs. Thus, FUCCI-expressing cells emit light of different colors in different phases providing a robust way to monitor cell cycle progression by fluorescence microscopy and flow cytometry but limiting the possibility to simultaneously visualize other markers. To overcome this limitation, we developed a single-color variant of FUCCI, called FUCCI-Red, which utilizes two red fluorescent proteins with distinct fluorescence lifetimes, mCherry and mKate2. Similarly to FUCCI, these proteins carry cell cycle-dependent degradation motifs to resolve G1 and S/G2/M phases. We showed utility of FUCCI-Red by visualizing cell cycle progression of cancer cells in 2D and 3D cultures and monitoring development of tumors in vivo by confocal and fluorescence lifetime imaging microscopy (FLIM). Single-channel registration and red-shifted spectra make FUCCI-Red sensor a promising instrument for multiparameter in vivo imaging applications, which was demonstrated by simultaneous detection of cellular metabolic state using endogenous fluorescence in the blue range.

Global computational alignment of tumor and cell line transcriptional profiles

Cell lines are key tools for preclinical cancer research, but it remains unclear how well they represent patient tumor samples. Direct comparisons of tumor and cell line transcriptional profiles are complicated by several factors, including the variable presence of normal cells in tumor samples. We thus develop an unsupervised alignment method (Celligner) and apply it to integrate several large-scale cell line and tumor RNA-Seq datasets. Although our method aligns the majority of cell lines with tumor samples of the same cancer type, it also reveals large differences in tumor similarity across cell lines. Using this approach, we identify several hundred cell lines from diverse lineages that present a more mesenchymal and undifferentiated transcriptional state and that exhibit distinct chemical and genetic dependencies. Celligner could be used to guide the selection of cell lines that more closely resemble patient tumors and improve the clinical translation of insights gained from cell lines.

Designer Self-Assembling Peptide Hydrogels to Engineer 3D Cell Microenvironments for Cell Constructs Formation and Precise Oncology Remodeling in Ovarian Cancer

Designer self-assembling peptides form the entangled nanofiber networks in hydrogels by ionic-complementary self-assembly. This type of hydrogel has realistic biological and physiochemical properties to serve as biomimetic extracellular matrix (ECM) for biomedical applications. The advantages and benefits are distinct from natural hydrogels and other synthetic or semisynthetic hydrogels. Designer peptides provide diverse alternatives of main building blocks to form various functional nanostructures. The entangled nanofiber networks permit essential compositional complexity and heterogeneity of engineering cell microenvironments in comparison with other hydrogels, which may reconstruct the tumor microenvironments (TMEs) in 3D cell cultures and tissue-specific modeling in vitro. Either ovarian cancer progression or recurrence and relapse are involved in the multifaceted TMEs in addition to mesothelial cells, fibroblasts, endothelial cells, pericytes, immune cells, adipocytes, and the ECM. Based on the progress in common hydrogel products, this work focuses on the diverse designer self-assembling peptide hydrogels for instructive cell constructs in tissue-specific modeling and the precise oncology remodeling for ovarian cancer, which are issued by several research aspects in a 3D context. The advantages and significance of designer peptide hydrogels are discussed, and some common approaches and coming challenges are also addressed in current complex tumor diseases.

Three-Dimensional Model of Dorsal Root Ganglion Explant as a Method of Studying Neurotrophic Factors in Regenerative Medicine

Neurotrophic factors play a key role in the development, differentiation, and survival of neurons and nerve regeneration. In the present study, we evaluated the effect of certain neurotrophic factors (NGF, BDNF, and GDNF) on axon growth and migration of Nestin-green fluorescent protein (GFP)-positive cells using a 3D model of dorsal root ganglion (DRG) explant culture in Matrigel. Our method generally represents a convenient model for assessing the effects of soluble factors and therapeutic agents on axon growth and nerve regeneration in R&D studies. By analyzing the DRG explants in ex vivo culture for 21 days, one can evaluate the parameters of neurite outgrowth and the rate of cell migration from the DRG explants into the Matrigel. For the current study, we used Nestin-GFP-expressing mice in which neural precursors express Nestin and the green fluorescent protein (GFP) under the same promoter. We revealed that GDNF significantly (two fold) stimulated axon outgrowth (p < 0.05), but not BDNF or NGF. It is well-known that axon growth can be stimulated by activated glial cells that fulfill a trophic function for regenerating nerves. For this reason, we evaluated the number of Nestin-GFP-positive cells that migrated from the DRG into the Matrigel in our 3D ex vivo explant model. We found that NGF and GDNF, but not BDNF, stimulated the migration of Nestin-GFP cells compared to the control (p < 0.05). On the basis of the aforementioned finding, we concluded that GDNF had the greatest stimulating potential for axon regeneration, as it stimulated not only the axon outgrowth, but also glial cell migration. Although NGF significantly stimulated glial cell migration, its effect on axon growth was insufficient for axon regeneration.

Screening of cytotoxic or cytostatic flavonoids with quantitative Fluorescent Ubiquitination-based Cell Cycle Indicator-based cell cycle assay

The Fluorescent Ubiquitination-based Cell Cycle Indicator (FUCCI) system can be used not only to study gene expression at a specific cell cycle stage, but also to monitor cell cycle transitions in real time. In this study, we used a single clone of FUCCI-expressing HeLa cells (FUCCI-HeLa cells) and monitored the cell cycle in individual live cells over time by determining the ratios between red fluorescence (RF) of RFP-Cdt1 and green fluorescence (GF) of GFP-Geminin. Cytotoxic and cytostatic compounds, the latter of which induced G2 or mitotic arrest, were identified based on periodic cycling of the RF/GF and GF/RF ratios in FUCCI-HeLa cells treated with anti-cancer drugs. With this cell cycle monitoring system, ten flavonoids were screened. Of these, apigenin and luteolin, which have a flavone backbone, were cytotoxic, whereas kaempferol, which has a flavonol backbone, was cytostatic and induced G2 arrest. In summary, we developed a system to quantitatively monitor the cell cycle in real time. This system can be used to identify novel compounds that modulate the cell cycle and to investigate structure-activity relationships.

Expression and Targeting of Tumor Markers in Gelfoam® Histoculture: Potential Individualized Assays for Immuno-Oncology

Tumor-specific antigens are important in the study of tumor biology, tumor diagnosis, and prognosis and as targets for tumor therapy. This chapter reviews patient colon, breast, and ovarian tumors in 3-dimensional Gelfoam^® histoculture maintaining in vivo-like expression of the important tumor antigens, for example TAG-72 and CEA. We have also reviewed that fluorescent antibodies can target tumors in Gelfoam^® histoculture, thereby providing an assay for individual patients for sensitivity to therapeutic antibodies which have become so important in immuno-oncology and other cancer therapies.

3D Sponge-Matrix Histoculture: An Overview

Three-dimensional cell culture and tissue culture (histoculture) is much more in vivo-like than 2D culture on plastic. Three-dimensional culture allows investigation of crucial events in tumor biology such as drug response, proliferation and cell cycle progression, cancer cell migration, invasion, metastasis, immune response, and antigen expression that mimic in vivo conditions. Three-dimensional sponge-matrix histoculture maintains the in vivo phenotype, including the formation of differentiated structures of normal and malignant tissues, perhaps due to cells maintaining their natural shape in a sponge-gel matrix such as Gelfoam^®. Sponge-matrix histoculture can also support normal tissues and their function including antibody-producing lymphoid tissue that allows efficient HIV infection, hair-growing skin, excised hair follicles that grow hair, pluripotent stem cells that form nerves, and much more.

Clinical Correlation of the Histoculture Drug Response Assay for Head and Neck Cancer

Gelfoam^® histoculture was utilized to develop the histoculture drug response assay (HDRA) for head and neck cancer. Specimens of head and neck tumors were evaluated for sensitivity to the following drugs: cisplatinum (CDDP), 5-fluorouracil (5-FU), and the combination of CDDP and 5-FU. In the first clinical study at UCSD, 10 of 12 patients with tumors that were drug sensitive in Gelfoam^® histoculture had either complete or partial response clinically. Comparisons of HDRA results, obtained with [³H]thymidine incorporation as the endpoint were made with clinical responses, i.e., complete response, partial response, or no response. The overall accuracy of the HDRA was 74% in this correlative clinical trial; the predictive positive value was 83%, the sensitivity was 71%, and the specificity was 78%. Seven of 11 patients with HDRA-resistant tumors demonstrated no response for a predictive negative value of 64%. In a subsequent study at Memorial Sloan Kettering Cancer Center, tumor specimens from 41 to 42 patients undergoing treatment for head and neck cancer were successfully evaluated by the HDRA. The histocultured tumors were treated with 5-FU and/or CDDP and a control group received no drug treatment. After completion of drug treatment, the relative cell survival in the tumors was determined using the MTT endpoint. Sensitivity was defined as a tumor inhibition rate (IR) of greater than 30%. Survival comparisons were performed using the generalized Wilcoxon test for the comparison of Kaplan-Meier survival curves. Resistance to 5-FU was observed in 13 cases (32%), to CDDP in 13 cases (32%), and to both agents in 11 cases (27%). The 2-year cause-specific survival was significantly greater for patients sensitive to 5-FU than patients who were resistant (85% vs. 64%), CDDP (86% vs. 64%), or both agents (85% vs. 63%). These results demonstrate the clinical usefulness of the HDRA for head and neck cancer.

Dynamic changes in the cell membrane on three dimensional low coherent quantitative phase microscopy (3D LC-QPM) after treatment with the near infrared photoimmunotherapy

Near infrared photoimmunotherapy (NIR-PIT) is a newly developed cancer therapy that relies on the binding of a near-infrared antibody photoabsorber conjugate (APC) to a cancer cell. Subsequent exposure to NIR light selectively induces rapid necrotic cell death on target-expressing cells with minimal off-target effects. When treated with NIR-PIT, targeted cells become swollen, develop blebs and burst within minutes of light exposure. Detailed spatial and temporal morphological changes of the cellular membrane of targeted cells treated with NIR-PIT have not been fully explored with state-of-the-art microscopic methods. In this study, we investigated the morphologic and kinetic effects of PIT on two types of cells, a spindle-shaped 3T3/Her cell and a spheric-shaped MDA-MB468 cell, after NIR-PIT using three-dimensional low-coherent quantitative phase microscopy (3D LC-QPM). Adhesive cells treated with NIR-PIT demonstrated region-specific cell membrane rupture occurring first on the distal free edge of the cell near the site of adhesion, in a process that was independent of cell shape. The results show that the peripheral portions of the cell membrane near the site of adhesion are particularly vulnerable to the effects of NIR-PIT, likely because these sites exhibit higher baseline surface tension.

Real-time monitoring of microdistribution of antibody-photon absorber conjugates during photoimmunotherapy in vivo

Photoimmunotherapy (PIT) is an emerging low side effect cancer therapy based on a monoclonal antibody (mAb) conjugated with a near-infrared (NIR) phthalocyanine dye IRDye 700DX. IR700 is fluorescent, can be used as an imaging agent, and also is phototoxic. It induces rapid cell death after exposure to NIR light. PIT induces highly selective cancer cell death, while leaving most of tumor blood vessels unharmed, leading to an effect called super-enhanced permeability and retention (SUPR). SUPR significantly improves the effectiveness of the anticancer drug. Currently, the therapeutic effects of PIT are monitored using the IR700 fluorescent signal based on macroscopic fluorescence reflectance imagery. This technique, however, lacks the resolution and depth information to reveal the intratumor heterogeneity of mAb-IR700 distribution. We applied a minimally invasive two-channel fluorescence fiber imaging system by combining the traditional fluorescence imaging microscope with two imaging fiber bundles (~0.85mm). This method monitored mAb-IR700 distribution and therapeutic effects during PIT at different intratumor locations (e.g., tumor surface vs. deep tumor) in situ and in real time simultaneously. This enabled evaluation of the therapeutic effects in vivo and treatment regimens. The average IR700 fluorescence intensity recovery after PIT to the tumor surface is 91.50%, while it is 100.63% in deep tumors. To verify the results, two-photon microscopy combined with a microprism was also used to record the mAb-IR700 distribution and fluorescence intensity of green fluorescent protein (GFP) at different tumor depths during PIT. After PIT treatment, there was significantly higher IR700 fluorescence recovery in deep tumor than in the tumor surface. This phenomenon can be explained by increased vascular permeability immediately after NIR-PIT. Fluorescence intensity of GFP at the tumor surface decreased significantly more compared to that of deep tumor and in controls (no PIT).

Therapeutic Cell-Cycle-Decoy Efficacy of a Telomerase-Dependent Adenovirus in an Orthotopic Model of Chemotherapy-Resistant Human Stomach Carcinomatosis Peritonitis Visualized With FUCCI Imaging

We have established an orthotopic nude-mouse model of gastric cancer carcinomatosis peritonitis, a recalcitrant disease in human patients. Human MKN45 poorly-differentiated human gastric cancer cells developed carcinomatosis peritonitis upon orthotopic transplantation in nude mice. The MKN45 cells expressed the fluorescent ubiquitination-based cell cycle indicator (FUCCI) that color codes the phases of the cell cycle. The intra-peritoneal tumors and ascites contained mostly quiescent G₁ /G_o cancer cells visualized as red by FUCCI imaging. Cisplatinum (CDDP) treatment did not reduce bloody ascites, and larger tumors formed in the peritoneal cavity after CDDP treatment in an early-stage carcinomatosis peritonitis orthotopic mouse model. Paclitaxel-treated mice had reduced ascites, but also had large tumor masses in the peritonium after treatment with cancer cells mostly in G₀ /G₁ , visualized by FUCCI red. In contrast, OBP-301 telomerase-dependent adenovirus-treated mice had no ascites and only small tumor nodules consisting of cancer cells mostly in S/G₂ phases in the early-stage carcinomatosis peritonitis model, visualized by FUCCI green. Furthermore, OBP-301 significantly reduced the size of tumors (P < 0.01) and ascites even in a late-stage carcinomatosis peritonitis model. These results suggest that quiescent peritoneally-disseminated gastric cancer cells are resistant to conventional chemotherapy, but OBP-301 significantly reduced the weight of the tumors and increased survival, suggesting clinical potential. J. Cell. Biochem. 118: 3635-3642, 2017. © 2016 Wiley Periodicals, Inc.

Cell-cycle-dependent drug-resistant quiescent cancer cells induce tumor angiogenesis after chemotherapy as visualized by real-time FUCCI imaging

We previously demonstrated that quiescent cancer cells in a tumor are resistant to conventional chemotherapy as visualized with a fluorescence ubiquitination cell cycle indicator (FUCCI). We also showed that proliferating cancer cells exist in a tumor only near nascent vessels or on the tumor surface as visualized with FUCCI and green fluorescent protein (GFP)-expressing tumor vessels. In the present study, we show the relationship between cell-cycle phase and chemotherapy-induced tumor angiogenesis using in vivo FUCCI real-time imaging of the cell cycle and nestin-driven GFP to detect nascent blood vessels. We observed that chemotherapy-treated tumors, consisting of mostly of quiescent cancer cells after treatment, had much more and deeper tumor vessels than untreated tumors. These newly-vascularized cancer cells regrew rapidly after chemotherapy. In contrast, formerly quiescent cancer cells decoyed to S/G2 phase by a telomerase-dependent adenovirus did not induce tumor angiogenesis. The present results further demonstrate the importance of the cancer-cell position in the cell cycle in order that chemotherapy be effective and not have the opposite effect of stimulating tumor angiogenesis and progression.

Efficacy of a Cell-Cycle Decoying Killer Adenovirus on 3-D Gelfoam®-Histoculture and Tumor-Sphere Models of Chemo-Resistant Stomach Carcinomatosis Visualized by FUCCI Imaging

Stomach cancer carcinomatosis peritonitis (SCCP) is a recalcitrant disease. The goal of the present study was to establish an in vitro-in vivo-like imageable model of SCCP to develop cell-cycle-based therapeutics of SCCP. We established 3-D Gelfoam^® histoculture and tumor-sphere models of SCCP. FUCCI-expressing MKN-45 stomach cancer cells were transferred to express the fluorescence ubiquinized cell-cycle indicator (FUCCI). FUCCI-expressing MKN-45 cells formed spheres on agarose or on Gelfoam^® grew into tumor-like structures with G₀/G₁ cancer cells in the center and S/G₂ cancer cells located in the surface as indicated by FUCCI imaging when the cells fluoresced red or green, respectively. We treated FUCCI-expressing cancer cells forming SCCP tumors in Gelfoam^® histoculture with OBP-301, cisplatinum (CDDP), or paclitaxel. CDDP or paclitaxel killed only cycling cancer cells and were ineffective against G₁/G₂ MKN-45 cells in tumors growing on Gelfoam^®. In contrast, the telomerase-dependent adenovirus OBP-301 decoyed the MKN-45 cells in tumors on Gelfoam^® to cycle from G₀/G₁ phase to S/G₂ phase and reduced their viability. CDDP- or paclitaxel-treated MKN-45 tumors remained quiescent and did not change in size. In contrast, OB-301 reduced the size of the MKN-45 tumors on Gelfoam^®. We examined the cell cycle-related proteins using Western blotting. CDDP increased the expression of p53 and p21 indicating cell cycle arrest. In contrast, OBP-301 decreased the expression of p53 and p21 Furthermore, OBP-301 increased the expression of E2F and pAkt as further indication of cell cycle decoy. This 3-D Gelfoam^® histoculture and FUCCI imaging are powerful tools to discover effective therapy of SCCP such as OBP-301.

Engineered bacteria detect spatial profiles in glucose concentration within solid tumor cell masses

Tumor heterogeneity makes cancer difficult to treat. Many small molecule cancer drugs target rapidly dividing cells on the periphery of tumors but have difficulty in penetrating deep into tumors and are ineffective at treating entire tumors. Targeting both rapidly dividing and slower growing regions of tumors is essential to effectively treat cancer. A cancer drug carrier that penetrates deep into tumors and identifies metabolically activity could supply treatment to those areas based on the local microenvironment. We hypothesized that glucose sensing bacteria could identify sugar gradients in solid tumors. To test this hypothesis, a genetic circuit was designed to trigger expression of a green fluorescent protein (GFP) reporter through the chemotaxis-osmoporin fusion protein, Trz1, a receptor for sensing glucose and ribose sugars. E. coli equipped with the Trz1-GFP expression system, were administered to an in vitro model of a continuously perfused tumor tissue that mimics systemic delivery and clearance of bacteria through a blood vessel adjacent to a solid tumor. The level of GFP expressed, per bacterium, was time independent and indicated the glucose concentration as a function of penetration depth within the microfluidic tumors. The measured glucose concentration, correlated (P-value = 2.6 × 10(-5) ) with tumor cell viability as a function of depth. Mathematical analysis predicted drug delivery by glucose-sensing bacteria would eliminate a higher percentage of the viable tumor cell population than a systemically administered drug. Glucose-sensing bacteria could deliver cancer therapies with increased drug penetration and nutrient-dependent dosing to continuously treat viable regions of cancer tissue that have a higher prevalence for metastatic dissemination. Biotechnol. Bioeng. 2016;113: 2474-2484. © 2016 Wiley Periodicals, Inc.

Heterogeneous cell-cycle behavior in response to UVB irradiation by a population of single cancer cells visualized by time-lapse FUCCI imaging

The present study analyzed the heterogeneous cell-cycle dependence and fate of single cancer cells in a population treated with UVB using a fluorescence ubiquitination-based cell-cycle (FUCCI) imaging system. HeLa cells expressing FUCCI were irradiated by 100 or 200 J/m(2) UVB. Modulation of the cell-cycle and apoptosis were observed by time-lapse confocal microscopy imaging every 30 min for 72 h. Correlation between cell survival and factors including cell-cycle phase at the time of the irradiation of UVB, mitosis and the G1/S transition were analyzed using the Kaplan-Meier method along with the log rank test. Time-lapse FUCCI imaging of HeLa cells demonstrated that UVB irradiation induced cell-cycle arrest in S/G2/M phase in the majority of the cells. The cells irradiated by 100 or 200 J/m(2) UVB during G0/G1 phase had a higher survival rate than the cells irradiated during S/G2/M phase. A minority of cells could escape S/G2/M arrest and undergo mitosis which significantly correlated with decreased survival of the cells. In contrast, G1/S transition significantly correlated with increased survival of the cells after UVB irradiation. UVB at 200 J/m(2) resulted in a greater number of apoptotic cells.

Improved micro-distribution of antibody-photon absorber conjugates after initial near infrared photoimmunotherapy (NIR-PIT)

Near infrared photoimmunotherapy (NIR-PIT), a targeted cancer therapy which uses an antibody-photo absorber conjugate (APC) and near infrared light exposure, dramatically improves nano-drug delivery into treated tumor beds due to enhanced vascular permeability. We investigated the micro-distribution of APCs in a variety of NIR-PIT treated tumors. Either cetuximab (cet) or trastuzumab (tra) conjugated with IR700 (cet-tra-IR700) was administered, as appropriate, to each mouse model of tumor. Tumor-bearing mice implanted with A431-GFP, MDAMB468-GFP, 3T3Her2-GFP or N87-GFP were separated into 5 groups: group 1=no treatment; group 2=cet-tra-IR700 i.v., no light exposure; group 3=cet-tra-IR700 i.v., NIR light exposure; group 4=cet-tra-IR700 i.v. and additional cet-tra-IR700 i.v. at 24h but no light exposure; group 5=cet-tra-IR700 i.v., NIR light exposure and additional cet-tra-IR700 i.v. immediately after NIR but no additional NIR light exposure. In vivo, ex vivo and microscopic fluorescence imaging was performed. Fluorescence from the surface of the tumor (s-tumor) was compared to fluorescence from deeper areas of the tumor (d-tumor). In general, there was no significant difference in the fluorescence intensity of GFP in the tumors among all groups, however the highest IR700 fluorescence intensity was consistently shown in group 5 tumors due to added APC after NIR-PIT. Fluorescence microscopy in all tumor types demonstrated that GFP relative fluorescence intensity (RFI) in s-tumor was significantly lower in group 3 and 5 (NIR-PIT groups) than in group 1, 2, and 4 (no NIR-PIT) yet there was no significant difference in d-tumor RFI among all groups. IR700 fluorescent RFI in the d-tumor was highest in group 5 (NIR-PIT+additional APC) compared to the other groups. Cell killing after NIR-PIT was primarily on the surface, however, APCs administered immediately after NIR-PIT penetrated deeper into tissue resulting in improved cell killing after a 2nd NIR-PIT session. This phenomenon is explained by increased vascular permeability immediately after NIR-PIT.

Anticancer efficacy of a nitric oxide-modified derivative of bifendate against multidrug-resistant cancer cells

The development of multidrug resistance (MDR) not only actively transports a wide range of cytotoxic drugs across drug transporters but is also a complex interaction between a number of important cellular signalling pathways. Nitric oxide donors appear to be a new class of anticancer therapeutics for satisfying all the above conditions. Previously, we reported furoxan‐based nitric oxide‐releasing compounds that exhibited selective antitumour activity in vitro and in vivo. Herein, we demonstrate that bifendate (DDB)‐nitric oxide, a synthetic furoxan‐based nitric oxide‐releasing derivative of bifendate, effectively inhibits the both sensitive and MDR tumour cell viability at a comparatively low concentration. Interestingly, the potency of DDB‐nitric oxide is the independent of inhibition of the functions and expressions of three major ABC transporters. The mechanism of DDB‐nitric oxide appears to be in two modes of actions by inducing mitochondrial tyrosine nitration and apoptosis, as well as by down‐regulating HIF‐1α expression and protein kinase B (AKT), extracellular signal‐regulated kinases (ERK), nuclear factor κB (NF‐κB) activation in MDR cells. Moreover, the addition of a typical nitric oxide scavenger significantly attenuated all the effects of DDB‐nitric oxide, indicating that the cytotoxicity of DDB‐nitric oxide is as a result of higher levels of nitric oxide release in MDR cancer cells. Given that acquired MDR to nitric oxide donors is reportedly difficult to achieve and genetically unstable, compound like DDB‐nitric oxide may be a new type of therapeutic agent for the treatment of MDR tumours.