Efficacy assessment of sustained intraperitoneal paclitaxel therapy in a murine model of ovarian cancer using bioluminescent imaging

Targeted Delivery of Anticancer Drug Loaded Charged PLGA Polymeric Nanoparticles Using Electrostatic Field

Pure positive electrostatic charges (PPECs) show suppressive effect on the proliferation and metabolism of invasive cancer cells without affecting normal tissues. PPECs are used for the delivery of drug-loaded polymeric nanoparticles (DLNs) capped with negatively charged poly(lactide-co-glycolide) (PLGA) and Poly(vinyl-alcohol) PVA into the tumor site of mouse models. The charged patch is installed on top of the skin in the mouse models' tumor region, and the controlled selective release of the drug is assayed by biochemical, radiological, and histological experiments on both tumorized models and normal rats' livers. It is found that DLNs synthesized by PLGA show great attraction to PPECs due to their stable negative charges, which would not degrade immediately in blood. The burst and drug release after less than 48h of this synthesized DLNs are 10% and 50%, respectively. These compounds can deliver the loaded-drug into the tumor site with the assistance of PPECs, and the targeted-retarded release will take place. Hence, local therapy can be achieved with much lower drug concentration (conventional chemotherapy [2 mg kg-1 ] versus DLNs-based chemotherapy [0.75 mg kg-1 ]) with negligible side effects in non-targeted organs. PPECs have many potential clinical applications for advanced-targeted chemotherapy with the lowest discernible side effects.

Evaluation of the in vitro and in vivo effect of liposomal doxorubicin along with oncolytic Newcastle disease virus on 4T1 cell line: Animal preclinical research

BACKGROUND

Breast cancer is one of the most common malignancies in women, with one in 20 globally. Oncolytic viruses have recently been the first step in the biological treatment of cancer, either genetically engineered or naturally occurring. They increase specifically inside cancer cells and destroy them without damaging normal tissues or producing a host immune response against tumour cells or expressing transgenes. One of the most known members of this family is the Newcastle disease virus (NDV), a natural oncolytic virus that selectively induces apoptosis and DNA fragmentation in human cancer cells.

METHODS

This study performed biochemical and molecular investigations with variable doses of NDV (32, 64, 128 HAU) and liposomal doxorubicin (9 mg/kg) on mouse triple-negative mammary carcinoma cell line 4T1 and BALB/c models tumours for the first time.

RESULTS

Real-time quantitative PCR analysis in NDV-treated animal tumours showed increased expression of P21, P27 and P53 genes and decreased expression of CD34, integrin Alpha 5, VEGF and VEGF-R genes. Additional assessments in treated mouse models also showed that NDV increased ROS production, induced apoptosis, reduced tumour size and significantly improved prognosis, with no adverse effect on normal tissues.

CONCLUSIONS

These findings all together might indicate that NDV in combination with chemotherapy drugs could improve prognosis in cancer patients although many more conditions should be considered.

Nanotechnology-integrated ovarian cancer metastasis therapy: Insights from the metastatic mechanisms into administration routes and therapy strategies

Ovarian cancer is a kind of malignant tumour which locates in the pelvic cavity without typical clinical symptoms in the early stages. Most patients are diagnosed in the late stage while about 60 % of them have suffered from the cancer cells spreading in the abdominal cavity. The high recurrence rate and mortality seriously damage the reproductive needs and health of women. Although recent advances in therapeutic regimes and other adjuvant therapies improved the overall survival of ovarian cancer, overcoming metastasis has still been a challenge and is necessary for achieving cure of ovarian cancer. To present potential targets and new strategies for curbing the occurrence of ovarian metastasis and the treatment of ovarian cancer after metastasis, the first section of this paper explained the metastatic mechanisms of ovarian cancer comprehensively. Nanomedicine, not limited to drug delivery, offers opportunities for metastatic ovarian cancer therapy. The second section of this paper emphasized the advantages of various administration routes of nanodrugs in metastatic ovarian cancer therapy. Furthermore, the third section of this paper focused on advances in nanotechnology-integrated strategies for targeting metastatic ovarian cancer based on the metastatic mechanisms of ovarian cancer. Finally, the challenges and prospects of nanotherapeutics for ovarian cancer metastasis therapy were evaluated. In general, the greatest emphasis on using nanotechnology-based strategies provides avenues for improving metastatic ovarian cancer outcomes in the future.

Combined inhibition of IL‑6 and IL‑8 pathways suppresses ovarian cancer cell viability and migration and tumor growth

Ovarian cancer is the most lethal gynecological cancer type in the United States. The success of current chemotherapies is limited by chemoresistance and side effects. Targeted therapy is a promising future direction for cancer therapy. In the present study, the efficacy of co‑targeting IL‑6 and IL‑8 in human ovarian cancer cells by bazedoxifene (Baze) + SCH527123 (SCH) treatment was examined. ELISA, cell viability, cell proliferation, cell migration, cell invasion, western blotting and peritoneal ovarian tumor mouse model analyses were performed to analyze the expression levels of IL‑6 and IL‑8, tumor growth, tumor migration and invasion, and the possible pathways of human ovarian cancer cell lines (SKOV3, CAOV3 and OVCAR3) and patient‑derived OV75 ovarian cancer cells. Each cell line was treated by monotherapy or combination therapy. The results demonstrated that IL‑6 and IL‑8 were secreted by human ovarian cancer cell lines. Compared with the DMSO control, the combination of IL‑6/glycoprotein 130 inhibitor Baze and IL‑8 inhibitor SCH synergistically inhibited cell viability in ovarian cancer cells. Baze + SCH also inhibited cell migration and invasion, suppressed ovarian tumor growth and inhibited STAT3 and AKT phosphorylation, as well as survivin expression. Therefore, co‑targeting the IL‑6 and IL‑8 signaling pathways may be an effective approach for ovarian cancer treatment.

Factors Influencing Luciferase-Based Bioluminescent Imaging in Preclinical Models of Brain Tumor

Bioluminescent imaging (BLI) is a powerful tool in biomedical research to measure gene expression and tumor growth. The current study examined factors that influence the BLI signal, specifically focusing on the tissue distribution of two luciferase substrates, D-luciferin and CycLuc1. D-luciferin, a natural substrate of firefly luciferase, has been reported to have limited brain distribution, possibly due to the efflux transporter, breast cancer resistance protein (Bcrp), at the blood-brain barrier. CycLuc1, a synthetic analog of D-luciferin, has a greater BLI signal at lower doses than D-luciferin, especially in the brain. Our results indicate that limited brain distribution of D-luciferin and CycLuc1 is predominantly dictated by their low intrinsic permeability across the cell membrane, where the efflux transporter, Bcrp, plays a relatively minor role. Both genetic ablation and pharmacological inhibition of Bcrp decreased the systemic clearance of both luciferase substrates, significantly increasing exposure in the blood and, hence, in organs and tissues. These data also indicate that the biodistribution of luciferase substrates can be differentially influenced in luciferase-bearing tissues, leading to a "tissue-dependent" BLI signal. The results of this study point to the need to consider multiple mechanisms that influence the distribution of luciferase substrates. SIGNIFICANCE STATEMENT: Bioluminescence is used to monitor many biological processes, including tumor growth. This study examined the pharmacokinetics, brain distribution, and the role of active efflux transporters on the luciferase substrates D-luciferin and CycLuc1. CycLuc1 has a more sustained systemic circulation time (longer half-life) that can provide an advantage for the superior imaging outcome of CycLuc1 over D-luciferin. The disparity in imaging intensities between brain and peripheral sites is due to low intrinsic permeability of these luciferase substrates across the blood-brain barrier.

Combination of selol nanocapsules and magnetic hyperthermia hinders breast tumor growth in aged mice after a short-time treatment

Short time treatment with reduced dosages of selol-loaded PLGA nanocapsules (NcSel) combined with magnetic hyperthermia (MHT) is evaluated in aged Erhlich tumor-bearing mice. Clinical, hematological, biochemical, genotoxic and histopathological parameters are assessed during 7 d treatment with NcSel and MHT, separately or combined. The time evolution of the tumor volume is successfully modeled using the logistic mathematical model. The combined therapy comprising NcSel and MHT is able to hinder primary tumor growth and a case of complete tumor remission is recorded. Moreover, no metastasis was diagnosed and the adverse effects are negligible. NcSel plus MHT may represent an effective and safe alternative to cancer control in aged patients. Future clinical trials are encouraged.

Bioengineering of virus-like particles as dynamic nanocarriers for in vivo delivery and targeting to solid tumours

Virus-like particles (VLPs) are known as self-assembled, non-replicative and non-infectious protein particles, which imitate the formation and structure of original wild type viruses, however, lack the viral genome and/or their fragments. The capacity of VLPs to encompass small molecules like nucleic acids and others has made them as novel vessels of nanocarriers for drug delivery applications. In addition, VLPs surface have the capacity to achieve variation of the surface display via several modification strategies including genetic modification, chemical modification, and non-covalent modification. Among the VLPs nanocarriers, Hepatitis B virus core (HBc) particles have been the most encouraging candidate. HBc particles are hollow nanoparticles in the range of 30-34 nm in diameter and 7 nm thick envelopes, consisting of 180 or 240 copies of identical polypeptide monomer. They also employ a distinctive position among the VLPs carriers due to the high-level synthesis, which serves as a strong protective capsid shell and efficient self-assembly properties. This review highlights on the bioengineering of HBc particles as dynamic nanocarriers for in vivo delivery and specific targeting to solid tumours.

Z, Shalileh S, Salemizadeh Parizi M, Vanaei S, Ghaderinia M, Abadijoo H, Taheri P, Reza Esmailinejad M, Sanati H, Reza Rostami M, Sadeghian R, Kordehlachin Y, Sadegh Mousavi‐kiasary SM, Mamdouh A, Hossein Miraghaie S, Baharvand H, Abdolahad M. Positive electrostatic therapy of metastatic tumors: selective induction of apoptosis in cancer cells by pure charges

BACKGROUND

We discovered that pure positive electrostatic charges (PECs) have an intrinsic suppressive effect on the proliferation and metabolism of invasive cancer cells (cell lines and animal models) without affecting normal tissues.

METHODS

We interacted normal and cancer cell lines and animal tumors with PECs by connecting a charged patch to cancer cells and animal tumors. many biochemical, molecular and radiological assays were carried out on PEC treated and control samples.

RESULTS

Correlative interactions between electrostatic charges and cancer cells contain critical unknown factors that influence cancer diagnosis and treatment. Different types of cell analyses prove PEC-based apoptosis induction in malignant cell lines. Flowcytometry and viability assay depict selective destructive effects of PEC on malignant breast cancer cells. Additionally, strong patterns of pyknotic apoptosis, as well as downregulation of proliferative-associated proteins (Ki67, CD31, and HIF-1α), were observed in histopathological and immunohistochemical patterns of treated mouse malignant tumors, respectively. Quantitative real-time polymerase chain reaction results demonstrate up/down-regulated apoptotic/proliferative transcriptomes (P21, P27, P53/CD34, integrin α5, vascular endothelial growth factor, and vascular endothelial growth factor receptor) in treated animal tumors. Expression of propidium iodide in confocal microscopy images of treated malignant tissues was another indication of the destructive effects of PECs on such cells. Significant tumor size reduction and prognosis improvement were seen in over 95% of treated mouse models with no adverse effects on normal tissues.

CONCLUSION

We discovered that pure positive electrostatic charges (PECs) have an intrinsic suppressive effect on the proliferation and metabolism of invasive cancer cells (cell lines and animal models) without affecting normal tissues. The findings were statistically and observationally significant when compared to radio/chemotherapy-treated mouse models. As a result, this nonionizing radiation may be used as a practical complementary approach with no discernible side effects after passing future human model studies.

Effective Detection and Monitoring of Glioma Using [18F]FPIA PET Imaging

BACKGROUND

Reprogrammed cellular metabolism is a cancer hallmark. In addition to increased glycolysis, the oxidation of acetate in the citric acid cycle is another common metabolic phenotype. We have recently developed a novel fluorine-18-labelled trimethylacetate-based radiotracer, [18F]fluoro-pivalic acid ([18F]FPIA), for imaging the transcellular flux of short-chain fatty acids, and investigated whether this radiotracer can be used for the detection of glioma growth.

METHODS

We evaluated the potential of [18F]FPIA PET to monitor tumor growth in orthotopic patient-derived (HSJD-GBM-001) and cell line-derived (U87, LN229) glioma xenografts, and also included [18F]FDG PET for comparison. We assessed proliferation (Ki-67) and the expression of lipid metabolism and transport proteins (CPT1, SLC22A2, SLC22A5, SLC25A20) by immunohistochemistry, along with etomoxir treatment to provide insights into [18F]FPIA uptake.

RESULTS

Longitudinal PET imaging showed gradual increase in [18F]FPIA uptake in orthotopic glioma models with disease progression (p < 0.0001), and high tumor-to-brain contrast compared to [18F]FDG (p < 0.0001). [18F]FPIA uptake correlated positively with Ki-67 (p < 0.01), SLC22A5 (p < 0.001) and SLC25A20 (p = 0.001), and negatively with CPT1 (p < 0.01) and SLC22A2 (p < 0.01). Etomoxir reduced [18F]FPIA uptake, which correlated with decreased Ki-67 (p < 0.05).

CONCLUSIONS

Our findings support the use of [18F]FPIA PET for the detection and longitudinal monitoring of glioma, showing a positive correlation with tumor proliferation, and suggest transcellular flux-mediated radiotracer uptake.

Enhancing delivery of small molecule and cell-based therapies for ovarian cancer using advanced delivery strategies

Ovarian cancer is the most lethal gynecological malignancy with a global five-year survival rate of 30-50%. First-line treatment involves cytoreductive surgery and administration of platinum-based small molecules and paclitaxel. These therapies were traditionally administered via intravenous infusion, although intraperitoneal delivery has also been investigated. Initial clinical trials of intraperitoneal administration for ovarian cancer indicated significant improvements in overall survival compared to intravenous delivery, but this result is not consistent across all studies performed. Recently cell-based immunotherapy has been of interest for ovarian cancer. Direct intraperitoneal delivery of cell-based immunotherapies might prompt local immunoregulatory mechanisms to act synergistically with the delivered immunotherapy. Based on this theory, pre-clinical in vivo studies have delivered these cell-based immunotherapies via the intraperitoneal route, with promising results. However, successful intraperitoneal delivery of cell-based immunotherapy and clinical adoption of this technique will depend on overcoming challenges of intraperitoneal delivery and finding the optimal combinations of dose, therapeutic and delivery route. We review the potential advantages and disadvantages of intraperitoneal delivery of cell-based immunotherapy for ovarian cancer and the pre-clinical and clinical work performed so far. Potential advanced delivery strategies, which might improve the efficacy and adoption of intraperitoneal delivery of therapy for ovarian cancer, are also outlined.

LncRNA TLR8-AS1 promotes metastasis and chemoresistance of ovarian cancer through enhancing TLR8 mRNA stability

Ovarian cancer is diagnosed as the most deadly gynecological tumor. Ovarian cancer metastasis affects chemoresistance and confers poor patient prognosis. In present work, we intended to elucidate whether long non-coding RNAs (lncRNAs) TLR8-AS1 regulated cell metastasis and chemoresistance of ovarian cancer, and uncover the molecular mechanism of TLR8-AS1 in the modulation of ovarian cancer progression. Firstly, bioinformatics analyses identified TLR8-AS1 as a cancer-associated fibroblasts regulated lncRNA in ovarian cancer. Further experiments revealed that TLR8-AS1 augmented cell metastasis and chemoresistance of ovarian cancer in vitro and in vivo. Moreover, TLR8-AS1 upregulates TLR8 by stabilizing TLR8 mRNA, thus activating NF-κB signaling and promoting ovarian cancer metastasis and chemoresistance. Besides, TCGA data analysis suggested that TLR8-AS1 is elevated in ovarian cancer in comparison to adjacent non-cancerous tissues. High TLR8-AS1 expression levels were measured in metastatic ovarian cancer and correlated with poor patient prognosis. The clinical data supported the mechanism and biological significance of TLR8-AS1 dysregulation in ovarian cancer development. Our work demonstrates that TLR8-AS1 can be applied as a diagnostic and prognostic indicator for ovarian cancer, and maybe an alternative target for the treatment of ovarian cancer.

Molecular imaging-monitored radiofrequency hyperthermia-enhanced intratumoral herpes simplex virus-thymidine kinase gene therapy for rat orthotopic ovarian cancer

Objective: To establish the technique of intratumoral combination therapy of radiofrequency hyperthermia (RFH) with herpes simplex virus-thymidine kinase/ganciclovir (HSV-TK/GCV) gene therapy for rat ovarian cancers.Material and methods: This study consisted of three parts: (1) in vitro experiments to establish the 'proof of principal' that combination of RFH and HSV-TK gene therapy has the synergistic effect on human ovarian cancer cells; (2) creation of bioluminescence imaging-detectable rat ovarian cancer model; and (3) in vivo experiments using this rat model to validate the technical feasibility of the combination therapy. Cells and nude rats were divided into four groups: (i) combination therapy (HSV-TK/GCV + RFH); (ii) RFH; (iii) HSV-TK/GCV; and (iv) phosphate-buffered saline (PBS). Data were analyzed using Dunnett t-test or Kruskal-Wallis test.Results: Cell proliferation assay demonstrated significantly greater reduction in viable cells with the combination therapy [0.52 (0.43, 0.61)] compared to other treatments [RFH 0.90 (0.84, 0.96), HSV-TK/GCV 0.71 (0.53, 0.88), PBS 1 (1, 1); p < .05]. For 24 rat models with bioluminescence imaging-detectable orthotopic ovarian cancer (n = 6 per group), optical imaging demonstrated significantly decreased relative bioluminescence signal with the combination therapy [0.81 (0.52, 1.08)] compared to other treatments [RFH 3.60 (2.34, 4.86), HSV-TK/GCV 2.21 (1.71, 2.71), PBS 3.74 (3.19, 4.29); p < .001]. Ultrasound imaging demonstrated the smallest relative tumor volume with the combination therapy [0.78 (0.45, 1.11) versus 3.50 (2.67, 4.33), 2.10 (0.83, 3.37), 3.70 (1.79, 5.61); p < .05].Conclusion: The feasibility of intratumoral RFH-enhanced HSV-TK/GCV gene therapy was established on a unique rat model with molecular imaging-detectable orthotopic ovarian cancer.

Targeting Pyruvate Kinase M2 and Lactate Dehydrogenase A Is an Effective Combination Strategy for the Treatment of Pancreatic Cancer

Reprogrammed glucose metabolism is one of the hallmarks of cancer, and increased expression of key glycolytic enzymes, such as pyruvate kinase M2 (PKM2) and lactate dehydrogenase A (LDHA), has been associated with poor prognosis in various malignancies. Targeting these enzymes could attenuate aerobic glycolysis and inhibit tumor proliferation. We investigated whether the PKM2 activator, TEPP-46, and the LDHA inhibitor, FX-11, can be combined to inhibit in vitro and in vivo tumor growth in preclinical models of pancreatic cancer. We assessed PKM2 and LDHA expression, enzyme activity, and cell proliferation rate after treatment with TEPP-46, FX-11, or a combination of both. Efficacy was validated in vivo by evaluating tumor growth, PK and LDHA activity in plasma and tumors, and PKM2, LDHA, and Ki-67 expression in tumor tissues following treatment. Dual therapy synergistically inhibited pancreatic cancer cell proliferation and significantly delayed tumor growth in vivo without apparent toxicity. Treatment with TEPP-46 and FX-11 resulted in increased PK and reduced LDHA enzyme activity in plasma and tumor tissues and decreased PKM2 and LDHA expression in tumors, which was reflected by a decrease in tumor volume and proliferation. The targeting of glycolytic enzymes such as PKM2 and LDHA represents a promising therapeutic approach for the treatment of pancreatic cancer.

Enhanced anti-tumor efficacy and safety with metronomic intraperitoneal chemotherapy for metastatic ovarian cancer using biodegradable nanotextile implants

The objective of this study was to evaluate intraperitoneal (IP) metronomic chemotherapy using sustained release paclitaxel (PTX) delivery from electrospun biodegradable polymeric yarns woven into suturable nanotextiles. Following confirmation of in vitro PTX efficacy in ID8-VEGF epithelial ovarian cancer cells, in vivo studies were performed upon surgical peritoneal implantation of nanotextile implants in orthotopic, syngeneic ID8-VEGF tumor-bearing C57BL/6 mice. In comparison to the clinical PTX-solution, there was a significant enhancement of anti-tumor efficacy and safety with PTX-nanotextiles. After 35-days, the peritoneum of tumor-bearing mice with PTX-nanotextiles was completely devoid of tumor nodules and ascitic fluid. Additionally, VEGF levels measured in peritoneal lavage fluid were 300-fold lower compared to PTX-solution and 600-fold lower as compared to untreated tumor-bearing animals. PTX-solution treated group also developed severe metastatic lesions and progressive ascitic fluid buildup. More importantly, no signs of systemic/ organ toxicity were observed in PTX-nanotextile implanted mice, unlike the systemic toxic effects induced by PTX-solution. Collectively, our results show the therapeutic and safety advantages offered by combining clinically translatable metronomic low-dose chemotherapy and IP pharmacokinetics using biodegradable nanotextile implants in addressing the challenges of late-stage ovarian cancer.

Evaluation of COC183B2 antibody targeting ovarian cancer by near-infrared fluorescence imaging

Objective

To evaluate the imaging potential of a novel near-infrared (NIR) probe conjugated to COC183B2 monoclonal antibodies (MAb) in ovarian cancer (OC).

Methods

The expression of OC183B2 antigen in OC was determined by immunohistochemical (IHC) staining using tissue microarrays with the H-score system and immunofluorescence (IF) staining of tumor cell lines. Imaging probes with the NIR fluorescent dye cyanine 7 (Cy7) conjugated to COC183B2 Mab were chemically engineered. OC183B2-positive human OC cells (SKOV3-Luc) were injected subcutaneously into BALB/c nude mice. Bioluminescent imaging (BLI) was performed to detect tumor location and growth. COC183B2-Cy7 at 1.1, 3.3, 10, or 30 μg were used for in vivo fluorescence imaging, and phosphate-buffered saline (PBS), free Cy7 dye and mouse isotype immunoglobulin G (IgG)-Cy7 (delivered at the same doses as COC183B2-Cy7) were used as controls.

Results

The expression of OC183B2 with a high H-score was more prevalent in OC tissue than fallopian tube (FT) tissue. Among 417 OC patients, the expression of OC183B2 was significantly correlated with the histological subtype, histological grade, residual tumor size, relapse state and survival status. IF staining demonstrated that COC183B2 specifically expressed in SKOV3 cells but not HeLa cells. In vivo NIR fluorescence imaging indicated that COC183B2-Cy7 was mainly distributed in the xenograft and liver with optimal tumor-to-background (T/B) ratios in the xenograft at 30 μg dose. The highest fluorescent signals in the tumor were observed at 96 h post-injection (hpi). Ex vivo fluorescence imaging revealed the fluorescent signals mainly from the tumor and liver. IHC analysis confirmed that xenografts were OC183B2 positive.

Conclusions

COC183B2 is a good candidate for NIR fluorescence imaging and imaging-guided surgery in OC.

Reinforcement of polymeric nanoassemblies for ultra-high drug loadings, modulation of stiffness and release kinetics, and sustained therapeutic efficacy

The optimization of current polymeric nanoparticle therapies is restricted by low drug loadings and limited tunability of core properties. To overcome these shortcomings, a novel self-association approach is utilized to fabricate a dual-loaded poly(1,2-glycerol carbonate)-graft-succinic acid-paclitaxel (PGC-PTX) conjugate nanoparticle (NP) in which the physical entrapment of free paclitaxel (PTX) affords unprecedented ultra-high drug loadings >100 wt%, modulation of mechanical stiffness, and tunable release kinetics. Despite high incorporation of free PTX (up to 50 wt%), the dual-loaded PGC-PTX nanocarriers (i.e., PGC-PTX + PTX NPs) exhibit controlled and sustained drug release over 15 days, without burst release effects. Importantly, optimization of drug/material efficiency concomitantly affords improved in vitro efficacy. In vivo, PGC-PTX + PTX NPs are safely administered at doses exceeding the median lethal dose of standard PTX, while a single high dose significantly extends survival relative to weekly PTX administrations in a murine model of peritoneal carcinomatosis.

Intraperitoneal chemotherapy for ovarian cancer using sustained-release implantable devices

INTRODUCTION

Epithelial ovarian cancer (EOC) remains to be the most lethal of all gynecological malignancies mainly due to its asymptomatic nature. The late stages are manifested with predominant metastases confined to the peritoneal cavity. Although there has been a substantial progress in the treatment avenue with different therapeutic interventions, the overall survival rate of patients remain poor due to relapse and drug resistance.

AREAS COVERED

The pharmacokinetic advantages offered by intraperitoneal (IP) chemotherapy due to peritoneal-plasma barrier can be potentially exploited for EOC relapse treatment. The ability to retain high concentrations of chemo-drugs with high AUC peritoneum/plasma for prolonged durations in the peritoneal cavity can be utilized effectively through the clinical adoption of drug delivery systems (DDSs) which obviates the need for indwelling catheters. The metronomic dosing strategy could enhance anti-tumor efficacy with a continuous, low dose of chemo-drugs providing minimal systemic toxicity.

EXPERT OPINION

The development of a feasible, non-catheter based, IP DDS, retaining the peritoneal-drug levels, with less systemic levels could offer significant survival advantages as a patient-compliant therapeutic strategy. Suturable-implantable devices based on metronomic dosing, eluting drug in a sustained manner at low doses, could be implanted surgically post-debulking for treatment of refractory EOC patients.

Engineering hepatitis B virus core particles for targeting HER2 receptors in vitro and in vivo

Hepatitis B Virus core (HBc) particles have been studied for their potential as drug delivery vehicles for cancer therapy. HBc particles are hollow nano-particles of 30–34 nm diameter and 7 nm thick envelopes, consisting of 180–240 units of 21 kDa core monomers. They have the capacity to assemble/dis-assemble in a controlled manner allowing encapsulation of various drugs and other biomolecules. Moreover, other functional motifs, i.e. receptors, receptor binding sequences, peptides and proteins can be expressed. This study focuses on the development of genetically modified HBc particles to specifically recognise and target human epidermal growth factor receptor-2 (HER2)-expressing cancer cells, in vitro and in vivo, for future cancer therapy. The non-specific binding capacity of wild type HBc particles was reduced by genetic deletion of the sequence encoding arginine-rich domains. A specific HER2-targeting was achieved by expressing the Z_HER2 affibodies on the HBc particles surface. In vitro studies showed specific uptake of Z_HER2-ΔHBc particles in HER2 expressing cancer cells. In vivo studies confirmed positive uptake of Z_HER2-ΔHBc particles in HER2-expressing tumours, compared to non-targeted ΔHBc particles in intraperitoneal tumour-bearing mice models. The present results highlight the potential of these nanocarriers in targeting HER2-positive metastatic abdominal cancer following intra-peritoneal administration.

Inhibition of bone loss with surface-modulated, drug-loaded nanoparticles in an intraosseous model of prostate cancer

Advanced-stage prostate cancer usually metastasizes to bone and is untreatable due to poor biodistribution of intravenously administered anticancer drugs to bone. In this study, we modulated the surface charge/composition of biodegradable nanoparticles (NPs) to sustain their blood circulation time and made them small enough to extravasate through the openings of the bone's sinusoidal capillaries and thus localize into marrow. NPs with a neutral surface charge, achieved by modulating the NP surface-associated emulsifier composition, were more effective at localizing to bone marrow than NPs with a cationic or anionic surface charge. These small neutral NPs (~150nm vs. the more usual ~320nm) were also ~7-fold more effective in localizing in bone marrow than large NPs. We hypothesized that NPs that effectively localize to marrow could improve NP-mediated anticancer drug delivery to sites of bone metastasis, thereby inhibiting cancer progression and preventing bone loss. In a PC-3M-luc cell-induced osteolytic intraosseous model of prostate cancer, these small neutral NPs demonstrated greater accumulation in bone within metastatic sites than in normal contralateral bone as well as co-localization with the tumor mass in marrow. Significantly, a single-dose intravenous administration of these small neutral NPs loaded with paclitaxel (PTX-NPs), but not anionic PTX-NPs, slowed the progression of bone metastasis. In addition, neutral PTX-NPs prevented bone loss, whereas animals treated with the rapid-release drug formulation Cremophor EL (PTX-CrEL) or saline (control) showed >50% bone loss. Neutral PTX-NPs did not cause acute toxicity, whereas animals treated with PTX-CrEL experienced weight loss. These results indicate that NPs with appropriate physical and sustained drug-release characteristics could be explored to treat bone metastasis, a significant clinical issue in prostate and other cancers.

The challenges facing block copolymer micelles for cancer therapy: In vivo barriers and clinical translation

The application of block copolymer micelles (BCMs) in oncology has benefitted from advances in polymer chemistry, drug formulation and delivery as well as in vitro and in vivo biological models. While great strides have been made in each of these individual areas, there remains some disappointment overall, citing, in particular, the absence of more BCM formulations in clinical evaluation and practice. In this review, we aim to provide an overview of the challenges presented by in vivo systems to the effective design and development of BCMs. In particular, the barriers posed by systemic administration and tumor properties are examined. The impact of critical features, such as the size, stability and functionalization of BCMs is discussed, while key pre-clinical endpoints and models are critiqued. Given clinical considerations, we present this work as a means to stimulate a renewed focus on the unique chemical versatility bestowed by BCMs and a measured grasp of representative in vitro and in vivo models.

Significant Therapeutic Efficacy with Combined Radioimmunotherapy and Cetuximab in Preclinical Models of Colorectal Cancer

Despite extensive efforts to improve the clinical management of patients with colorectal cancer, approved treatments for advanced disease offer limited survival benefit. Therefore, the identification of novel treatment strategies is essential. We evaluated the preclinical efficacy of combination radioimmunotherapy, using a humanized (131)I-labeled anti-carcinoembryonic antigen antibody ((131)I-huA5B7), with cetuximab in colorectal cancer (CRC).

METHODS

Three human CRC cell lines--SW1222, LoVo, and LS174T--were used to generate subcutaneous xenografts, and stably luciferase-transfected SW1222 cells were used to establish a model of hepatic metastases in immunocompromised mice. Imaging and biodistribution studies were conducted to confirm the selective tumor localization of (131)I-huA5B7. Efficacy was evaluated on the basis of tumor growth delay and survival, along with markers of DNA damage response, cell cycle, proliferation, and apoptosis.

RESULTS

Selective tumor targeting was achieved with (131)I-huA5B7 alone or in combination with cetuximab without observable toxicity. Compared with monotherapy, combining cetuximab with radioimmunotherapy significantly and synergistically reduced tumor growth and prolonged survival of mice in 2 of the subcutaneous and in the metastatic tumor model. Evidence of DNA damage, G2/M arrest, significantly decreased proliferation, and increased apoptosis were observed with radioimmunotherapy and the combination therapy. However, a significant decrease in DNA-protein kinase expression with the combination regimen suggests that the addition of cetuximab suppressed DNA repair.

CONCLUSION

Our results demonstrate enhanced therapeutic efficacy with the combination of cetuximab and radioimmunotherapy in CRC, which could potentially translate into successful clinical outcomes. This strategy could improve the treatment of residual disease postoperatively and ultimately prevent or delay recurrence. Furthermore, other carcinoembryonic antigen-expressing malignancies could also benefit from this approach.

Pharmacodynamic assays to facilitate preclinical and clinical development of pre-mRNA splicing modulatory drug candidates

The spliceosome has recently emerged as a new target for cancer chemotherapy and novel antitumor spliceosome targeted agents are under development. Here, we describe two types of novel pharmacodynamic assays that facilitate drug discovery and development of this intriguing class of innovative therapeutics; the first assay is useful for preclinical optimization of small-molecule agents that target the SF3B1 spliceosomal protein in animals, the second assay is an ex vivo validated, gel-based assay for the measurement of drug exposure in human leukocytes. The first assay utilizes a highly specific bioluminescent splicing reporter, based on the skipping of exons 4–11 of a Luc-MDM2 construct, which specifically yields active luciferase when treated with small-molecule spliceosome modulators. We demonstrate that this reporter can be used to monitor alternative splicing in whole cells in vitro. We describe here that cell lines carrying the reporter can be used in vivo for the efficient pharmacodynamic analysis of agents during drug optimization and development. We also demonstrate dose- and time-dependent on-target activity of sudemycin D6 (SD6), which leads to dramatic tumor regression. The second assay relies on the treatment of freshly drawn human blood with SD6 ex vivo treatment. Changes in alternative splicing are determined by RT-PCR using genes previously identified in in vitro experiments. The Luc-MDM2 alternative splicing bioluminescent reporter and the splicing changes observed in human leukocytes should allow for the more facile translation of novel splicing modulators into clinical application.

Dual-layer surface coating of PLGA-based nanoparticles provides slow-release drug delivery to achieve metronomic therapy in a paclitaxel-resistant murine ovarian cancer model

Development of drug resistance is a central challenge to the treatment of ovarian cancer. Metronomic chemotherapy decreases the extent of drug-free periods, thereby hindering development of drug resistance. Intraperitoneal chemotherapy allows for treatment of tumors confined within the peritoneum, but achieving sustained tumor-localized chemotherapy remains difficult. We hypothesized that modulating the surface properties of poly(lactic-co-glycolic acid) (PLGA)-based nanoparticles could enhance their drug retention ability and extend their release profile, thereby enabling metronomic, localized chemotherapy in vivo. Paclitaxel was encapsulated in particles coated with a layer of polydopamine and a subsequent layer of poly(ethylene glycol) (PEG). These particles achieved a 3.8-fold higher loading content compared to that of nanoparticles formulated from linear PLGA-PEG copolymers. In vitro release kinetic studies and in vivo drug distribution profiles demonstrate sustained release of paclitaxel. Although free drug conferred no survival advantage, low-dose intraperitoneal administration of paclitaxel-laden surface-coated nanoparticles to drug-resistant ovarian tumor-bearing mice resulted in significant survival benefits in the absence of any apparent systemic toxicity.

Continuous intraperitoneal carboplatin delivery for the treatment of late-stage ovarian cancer

The rate of failure of chemotherapy treatment in ovarian cancer remains high, resulting in a low 5-year survival rate of 20-40% in patients that present with advanced-stage disease. Treatment-free periods between cycles of chemotherapy may contribute to accelerated tumor cell proliferation and decreased treatment response. The elimination of treatment-free breaks has been deemed beneficial in the context of cell-cycle-specific agents. The potential benefit of this approach for non-cell-cycle-specific agents has not yet been elucidated. The present study is the first to address this issue by investigating the impact of continuous versus intermittent intraperitoneal administration of carboplatin over a 14 day period to SCID mice bearing SKOV-3 ovarian cancer xenografts. Immunostaining of tumor sections was employed to quantify tumor proliferation, angiogenesis, and apoptosis using Ki-67, CD-31, caspase-3 (CASP3), and terminal deoxytransferase-mediated dUTP nick-end labeling (TUNEL). Continuous ip administration of carboplatin resulted in greater tumor growth inhibition than intermittent therapy (p < 0.05). Significantly greater tumor cell apoptosis and less cell proliferation and angiogenesis were measured in tumors of mice treated with continuous carboplatin as compared to both intermittent and control groups. These results indicate that continuous local administration may be a promising approach to improve the effectiveness of platinum-based chemotherapy regimens.

Thermosensitive depot-forming injectable phosphatidylcholine blends tailored for localized drug delivery

A thermosensitive depot-forming system was developed for sustained and localized delivery of the anticancer drug, paclitaxel. The formulation is injectable as a melt slightly above the body temperature and forms a solid depot upon cooling to 37°C. The thermosensitive system was prepared by blending various combinations of phosphatidylcholines at specific weight ratios solubilized in laurinaldehyde. Of the blends investigated, distearoyl-phosphatidylcholine (DSPC) and egg-phosphatidylcholine (ePC) were found to be most miscible. A liquid-to-gel phase transition temperature (TC ) of 39°C was observed for the 70:30 (w/w) DSPC-ePC blend and a TC of 38.4°C with the addition of paclitaxel. Blends containing higher concentrations of ePC had a greater degree of swelling and weight loss. Furthermore, microscopy revealed an increase in porosity and erosion as the amount of ePC was increased in blends incubated in biologically relevant media. DSPC-ePC blends provided sustained release of paclitaxel over a 30-day period and the rate of drug release increased as the amount of ePC increased. Overall, the relationships established between the composition and properties of the blend may be employed to tailor the thermosensitive injectable formulation for localized chemotherapy of solid tumors.

Poly(ethylene glycol)-block-poly(ε-caprolactone) micelles for combination drug delivery: evaluation of paclitaxel, cyclopamine and gossypol in intraperitoneal xenograft models of ovarian cancer

Ovarian cancer is the most lethal gynecological malignancy, characterized by a high rate of chemoresistance. Current treatment strategies for ovarian cancer focus on novel drug combinations of cytotoxic agents and molecular targeted agents or novel drug delivery strategies that often involve intraperitoneal (IP) injection. Poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-b-PCL) micelles were loaded with paclitaxel (cytotoxic agent), cyclopamine (hedgehog inhibitor), and gossypol (Bcl-2 inhibitor). After physicochemical studies focusing on combination drug solubilization, 3-drug PEG-b-PCL micelles were evaluated in vitro in 2-D and 3-D cell culture and in vivo in xenograft models of ovarian cancer, tracking bioluminescence signals from ES-2 and SKOV3 human ovarian cancer cell lines after IP injection. 3-Drug PEG-b-PCL micelles were not significantly more potent in 2-D cell culture in comparison to paclitaxel; however, they disaggregated ES-2 tumor spheroids, whereas single drugs or 2-drug combinations only slowed growth of ES-2 tumor spheroids or had no noticeable effects. In ES-2 and SKOV3 xenograft models, 3-drug PEG-b-PCL micelles had significantly less tumor burden than paclitaxel based on bioluminescence imaging, 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) PET imaging, and overall survival. (18)F-FLT-PET images clearly showed that 3-drug PEG-b-PCL micelles dramatically reduce tumor volumes over paclitaxel and vehicle controls. In summary, PEG-b-PCL micelles enable the IP combination drug delivery of paclitaxel, cyclopamine and gossypol, resulting in tumor growth inhibition and prolonged survival over paclitaxel alone. These results validate a novel treatment strategy for ovarian cancer based on drug combinations of cytotoxic agents and molecular targeted agents, delivered concurrently by a nanoscale drug delivery system, e.g. PEG-b-PCL micelles.

An injectable depot system for sustained intraperitoneal chemotherapy of ovarian cancer results in favorable drug distribution at the whole body, peritoneal and intratumoral levels

The current study characterizes the impact of docetaxel (DTX) distribution on efficacy following sustained intraperitoneal (IP) chemotherapy in murine models of ovarian cancer. A polymer-lipid biodegradable depot (PoLigel) was used to deliver DTX in a sustained manner over 21-days following IP administration. Distribution and efficacy studies were carried out in SCID mice bearing SKOV3 IP solid tumors or C57BL/6 mice with ID8 IP ascites fluid. In addition, a subcutaneous (SC) SKOV3 model was used to determine whether systemic drug levels that result from IP administration of the PoLigel influence antitumor efficacy. Immunostained IP and SC SKOV3 tumor sections were used to study cell death, intratumoral drug distribution and tumor penetration. Sustained concentrations of DTX were observed in plasma, tissue, tumor and ascites over the entire study period. Drug accumulation was several fold greater in tumors and ascites when compared to plasma levels. Sustained chemotherapy resulted in significant reduction in tumor burden and ascites volume. IP tumors showed greater cell death compared to the SC tumors as seen by higher TUNEL and caspase-3 expression. At the intratumoral level, DTX distributed more towards the core of IP tumors compared to the SC tumors. Tumor penetration of drug from nearest blood vessel was 1.5 fold greater in the IP tumors than the SC tumors. Overall, favorable drug distribution at the whole-body, peritoneal and intratumoral levels in combination with local and systemic sustained drug exposure contribute to the high efficacy observed. These results encourage the clinical use of IP sustained chemotherapy for ovarian cancer.

Intraperitoneal administration of novel doxorubicin loaded polymeric delivery systems against peritoneal carcinomatosis: experimental study in a murine model of ovarian cancer

OBJECTIVE

Peritoneal spread is an adverse outcome in ovarian cancer. Despite clinical efficiency, intraperitoneal (i.p.) chemotherapy after cytoreductive surgery is associated with high systemic and local toxicity. Two polymer-drug delivery systems (P-HYD1-DOX and P-HYD2-DOX) were developed for i.p. administration by conjugating doxorubicin (DOX) to a poly(l-Lysine citramide) polymer carrier with a hydrazone-based degradable spacer. The aim of this study was to assess the antitumoral efficacy of these two conjugates in a xenograft model of human ovarian carcinomatosis.

METHODS

Peritoneal carcinomatosis was generated in athymic mice by i.p. injection of SKOV3-Luc cells. Free DOX, P-HYD1-DOX and P-HYD2-DOX solutions were administered i.p. at the same dose of 10 mg/kg (DOX eq.). For each treatment, tumor load and therapeutic efficacy were compared to untreated mice and assessed by bioluminescence imaging and survival rates. Toxicity profiles in each group and biodistribution of P-HYD2-DOX after i.p. administration were also determined.

RESULTS

P-HYD-1-DOX and P-HYD-2-DOX demonstrated significant antitumoral efficacy against peritoneal carcinomatosis. Compared to untreated group, P-HYD1-DOX improved median survival times from 58 to 105 days. For P-HYD2-DOX, median survival was not reached after a follow-up of 120 days. Bioluminescence showed high efficacy of P-HYD-2-DOX compared to free DOX but the difference was not significant. Biodistribution study confirmed that free and active DOX were successively released from P-HYD2-DOX in vivo. P-HYD-DOX conjugates were well tolerated by mice after i.p. injection.

CONCLUSION

P-HYD-DOX conjugates demonstrated significant activity against peritoneal carcinomatosis in a xenograft model of ovarian carcinomatosis and their ability to release active DOX in i.p. deposits and tumor. These features are of clinical interest for i.p. administration in the treatment of ovarian peritoneal carcinomatosis after cytoreductive surgery.

Chemotherapy dosing schedule influences drug resistance development in ovarian cancer

Drug resistance leads to chemotherapy failure and is responsible for the death of a great majority of patients with metastatic, late-stage ovarian cancer. The present study addressed whether changes in the chemotherapy dosing schedule affect the development, further worsening, or circumvention of drug resistance in chemosensitive and chemoresistant ovarian cancer. Severe combined immunodeficient mice bearing HeyA8 and HeyA8-MDR xenografts were treated with docetaxel intermittently (1×/wk or 3×/wk) or continuously for 21 days. Tumor mRNA expression of genes implicated in docetaxel resistance was measured by quantitative real-time-PCR. Analyzed genes included those encoding for the drug efflux transporters mdr1 and mrp7 and for molecules that interfere with or overcome the effects of docetaxel, including β-tubulinIII, actinin4, stathmin1, bcl2, rpn2, thoredoxin, and akt2. In both models, continuous docetaxel resulted in greater antitumor efficacy than 1×/wk or 3×/wk dosing and did not induce upregulation of any analyzed genes. Once weekly dosing caused upregulation of various drug resistance-related genes, especially in chemoresistant xenografts. More frequent, 3×/wk dosing diminished this effect, although levels of various genes were higher than for continuous chemotherapy. Drug efflux transporter expression was further examined by Western blotting, confirming that intermittent, but not continuous, docetaxel induced significant upregulation. Overall, our results show that the presence and length of treatment-free intervals contribute to the development of drug resistance. Elimination of these intervals by continuous dosing resulted in superior antitumor efficacy and prevented drug resistance induction in chemosensitive and chemoresistant disease. These results encourage the clinical implementation of continuous chemotherapy to overcome and/or prevent drug resistance in newly diagnosed and recurrent, refractory ovarian cancer.