Doxorubicin–polyphosphazene conjugate hydrogels for locally controlled delivery of cancer therapeutics

Poly(organophosphazene)–doxorubicin (DOX) conjugate bearing hydrophobic l-isoleucine ethyl ester (IleOEt) and hydrophilic α-amino-ω-methoxy-poly(ethylene glycol) with molecular weight of 550 Da (AMPEG 550) along with carboxylic acid as a functional group was synthesized to create a drug delivery system, which is based on locally injectable, biodegradable, and thermosensitive hydrogels. In addition to the evaluation of the in vitro and in vivo antitumor activities, the physicochemical properties, hydrolytic degradation, and DOX release profile of the poly(organophosphazene)–DOX conjugate were determined. The aqueous solution of the polymer–DOX conjugate showed a sol–gel transition behavior depending on temperature changes. Based on the in vivo antitumor activities of the locally injected poly(organophosphazene)–DOX conjugate into the tumor-induced nude mice, the conjugate hydrogel after the local injection at the tumor site was shown to inhibit tumor growth more effectively with less toxicity and much longer than doxorubicin and saline as controls, indicating that tumor active DOX from the conjugate hydrogel is released slowly over a longer period of time and effectively accumulated locally in the tumor sites. These results suggest that the poly(organophosphazene)–doxorubicin conjugates hold great potential for use in preclinical and clinical studies as single and/or combination therapies.     

Biodegradable and amphiphilic block copolymer–doxorubicin conjugate as polymeric nanoscale drug delivery vehicle for breast cancer therapy

Polymeric nanoparticles have shown great promise as attractive vehicles for drug delivery. In this study, we designed, prepared and characterized biodegradable amphiphilic triblock HPMA copolymer–doxorubicin (copolymer–DOX) conjugate based nanoparticle as enzyme-sensitive drug delivery vehicle. The enzyme-sensitive peptide GFLGKGLFG was introduced to the main chain of the copolymer with hydrophilic and hydrophobic blocks. The triblock HPMA polymer–DOX conjugate with high molecules (Mw 90 kDa) can be degraded to product with low molecule weight (Mw 44 kDa) below the renal threshold. The copolymer–DOX conjugate can self-assemble into compact nanoparticle, which was characterized by scanning electron microscope (SEM) and atomic force microscope (AFM) studies. This polymeric nanoparticle substantially enhanced antitumor efficacy compared to the free DOX, exhibiting much higher effects on inhibiting proliferation and inducing apoptosis on the 4T1 murine breast cancer model confirmed by the evidences from mice weight shifts, tumor growth curves, tumor growth inhibition (TGI), immunohistochemical analysis and histological assessment. The in vivo toxicity evaluation demonstrated that the polymeric nanoparticle reduced DOX-induced toxicities and presented no significant side effects to normal organs of both tumor bearing and healthy mice as measured by body weight shift, blood routine test and histological analysis. Therefore, the triblock HPMA copolymer–DOX conjugate based nanoparticle is promising as a potential drug delivery vehicle for breast cancer therapy.     

Preparation and in vitro delivery performance of chitosan–alginate microcapsule for IgG

The study aimed to develop chitosan–alginate microcapsule as an oral delivery carrier for IgG. Bovine serum albumin (BSA) was used as the protein to be encapsulated while determining the microcapsule formula by evaluating encapsulation efficiency (EE), loading capacity (LC) and release profile. Results suggested that the optimal formula was composed of 0.1% chitosan, 0.5% CaCl₂, 2% sodium alginate and the loading rate of BSA reached 25%. IgG was substituted for BSA and an IgG microcapsule was prepared following the above formula. The EE and LC of the resulted IgG microcapsule reached 76.83% and 18.53%. After 2?h incubation in simulated gastric fluid, the activity of IgG in the microcapsule remained at 79.79% and the total release rate of IgG in a simulated intestinal fluid reached 82.52%. This encapsulation formula was proved to be an effective oral delivery system which would protect the IgG from severe gastric conditions and guarantee an efficient release in the intestinal tract.     

Kernel canonical correlation analysis for assessing gene–gene interactions and application to ovarian cancer

Although single-locus approaches have been widely applied to identify disease-associated single-nucleotide polymorphisms (SNPs), complex diseases are thought to be the product of multiple interactions between loci. This has led to the recent development of statistical methods for detecting statistical interactions between two loci. Canonical correlation analysis (CCA) has previously been proposed to detect gene–gene coassociation. However, this approach is limited to detecting linear relations and can only be applied when the number of observations exceeds the number of SNPs in a gene. This limitation is particularly important for next-generation sequencing, which could yield a large number of novel variants on a limited number of subjects. To overcome these limitations, we propose an approach to detect gene–gene interactions on the basis of a kernelized version of CCA (KCCA). Our simulation studies showed that KCCA controls the Type-I error, and is more powerful than leading gene-based approaches under a disease model with negligible marginal effects. To demonstrate the utility of our approach, we also applied KCCA to assess interactions between 200 genes in the NF-κB pathway in relation to ovarian cancer risk in 3869 cases and 3276 controls. We identified 13 significant gene pairs relevant to ovarian cancer risk (local false discovery rate <0.05). Finally, we discuss the advantages of KCCA in gene–gene interaction analysis and its future role in genetic association studies.     

PEGylated liposomes with NGR ligand and heat-activable cell-penetrating peptide–doxorubicin conjugate for tumor-specific therapy

Cell-penetrating peptides (CPPs) mediated tumor-oriented nanocarriers have been widely studied by researchers recently. However, applications of CPPs in vivo were usually hampered by their loss in untargeted tissues and enzymatic degradation. These shortfalls required strategies to camouflage CPPs before their arrival at the targeted site. In this work, we constructed a thermosensitive liposome (TSL) containing Asparagines–Glycine–Arginine (NGR) peptide as the targeting moiety and heat-activable cell-penetrating peptide–doxorubicin conjugate for enhancing specific cancer therapy. Different to the masking strategies of CPPs reported, CPPs existing in conjugation form of CPPs and doxorubicin (CPP-Dox) were hidden in TSL to cloak and protect CPPs. Meanwhile, NGR moiety and local tumor hyperthermia were utilized to achieve specific targeting of CPPs to the tumor. The nanocarrier (CPP-Dox/NGR-TSL) prepared in this work possessed suitable physiochemical properties such as small particle size of about 90 nm, high drug encapsulation efficiency of approximately 95%, good stability in the medium containing 10% fetal bovine serum (FBS) and so on. In vitro experiments on Human fibrosarcoma cells (HT-1080) and human breast adenocarcinoma cells (MCF-7) verified the specific targeting ability and enhanced intracellular drug delivery of the liposomes to HT-1080 cells. Furthermore, comparing with NGR-targeted TSL containing Dox (Dox/NGR-TSL), the results of intravenous administration showed CPP-Dox/NGR-TSL significantly inhibited tumor growth in nude mice xenografted HT-1080 tumors and excellent body safety. In conclusion, the nanocarrier constructed in this study would be a safe and efficiently drug delivery system for specific cancer treatment.     

Multifunctional polyglycerol-grafted Fe₃O₄@SiO₂ nanoparticles for targeting ovarian cancer cells

Ligand-mediated magnetic resonance (MR) contrast agents would be highly desirable for cancer diagnosis. In the present study, nanoparticles of Fe?O? core with fluorescent SiO? shell were synthesized and grafted with hyperbranched polyglycerol (HPG-grafted Fe?O?@SiO? nanoparticles). These nanoparticles have a hydrodynamic diameter of 47.0 ± 4.0 nm, and are very stable in aqueous solution as well as in cell culture medium. Numerous surface hydroxyl groups of these nanoparticles were conjugated with folic acid by a thiol 'click' reaction. The successful covalent attachment of folic acid on the nanoparticles was confirmed by FTIR and XPS analyses. Both MR imaging and fluorescence microscopy show significant preferential uptake of the folic acid-conjugated polyglycerol-grafted Fe?O?@SiO? (FA-HPG-grafted Fe?O?@SiO?) nanoparticles by human ovarian carcinoma cells (SKOV-3) as compared to macrophages and fibroblasts. Such nanoparticles can potentially be used to provide real-time imaging in ovarian cancer resection.     

The use of α-conotoxin ImI to actualize the targeted delivery of paclitaxel micelles to α7 nAChR-overexpressing breast cancer

Alpha7 nicotinic acetylcholine receptor (α7 nAChR), a ligand-gated ion channel, is increasingly emerging as a new tumor target owing to its expression specificity and significancy for cancer. In an attempt to increase the targeted drug delivery to the α7 nAChR-overexpressing tumors, herein, α-conotoxin ImI, a disulfide-rich toxin with highly affinity for α7 nAChR, was modified on the PEG-DSPE micelles (ImI-PMs) for the first time. The DLS, TEM and HPLC detections showed the spherical nanoparticle morphology about 20 nm with negative charge and high drug encapsulation. The ligand modification did not induce significant differences. The immunofluorescence assay confirmed the expression level of α7 nAChR in MCF-7 cells. In vitro and in vivo experiments demonstrated that the α7 nAChR-targeted nanomedicines could deliver more specifically and faster into α7 nAChR-overexpressing MCF-7 cells. Furthermore, fluo-3/AM fluorescence imaging technique indicated that the increased specificity was attributed to the ligand-receptor interaction, and the inducitivity for intracellular Ca²⁺ transient by ImI was still remained after modification. Moreover, paclitaxel, a clinical frequently-used anti-tumor drug for breast cancer, was loaded in ImI-modified nanomedicines to evaluate the targeting efficacy. Besides of exhibiting greater cytotoxicity and inducing more cell apoptosis in vitro, paclitaxel-loaded ImI-PMs displayed stronger anti-tumor efficacy in MCF-7 tumor-bearing nu/nu mice. Finally, the active targeting system showed low systemic toxicity and myelosuppression evidenced by less changes in body weight, white blood cells, neutrophilic granulocyte and platelet counts. In conclusion, α7 nAChR is also a promising target for anti-tumor drug delivery and in this case, α-conotoxin ImI-modified nanocarrier is a potential delivery system for targeting α7 nAChR-overexpressing tumors.     

The anticancer efficacy of pixantrone-loaded liposomes decorated with sialic acid–octadecylamine conjugate

Based on the knowledge that sialic acid is a critical element for tumor development and its receptors are highly expressed on the tumor-associated macrophages (TAMs) which play important roles in the growth and metastasis of tumors, we synthesized a sialic acid–octadecylamine conjugate (SA–ODA) and anchored it on the surface of pixantrone (Pix)-loaded liposomes, to achieve an improved anticancer effect. Four Pix formulations (Pix-S, Pix-CL, Pix-PL and Pix-SAL represent solution, conventional liposome, stealth liposome, and SA–ODA modified liposome, respectively) were developed, and various parameters, including drug loading, stability, in vitro release, cytotoxicity and pharmacokinetics, were evaluated. The tumor growth inhibition and toxicity studies were performed in S180-bearing Kunming mice. Pix-S exhibited a strong toxicity to the immune system, accelerated the growth of tumors and reduced the lifespan of mice. In contrast, Pix-SAL displayed the strongest anticancer and life-prolonging effects among all of the formulations in this study. More importantly, injection of Pix-SAL induced a phenomenon whereby the cancerous tissues were “shed” from mice, after which the wound healed. We speculate that this special efficacy may be partly due to the killing of TAMs by Pix-SAL. This study suggests that SA–ODA modified liposomes may serve as an effective intravenous delivery vehicle for Pix.     

Targeted depletion of tumour-associated macrophages by an alendronate–glucomannan conjugate for cancer immunotherapy

Tumour-associated macrophages (TAMs) are a set of macrophages residing in the tumour microenvironment. They play essential roles in mediating tumour angiogenesis, metastasis and immune evasion. Delivery of therapeutic agents to eliminate TAMs can be a promising strategy for cancer immunotherapy but an efficient vehicle to target these cells is still in pressing need. In this study, we developed a bisphosphonate–glucomannan conjugate that could efficiently target and specifically eliminate TAMs in the tumour microenvironment. We employed the polysaccharide from Bletilla striata (BSP), a glucomannan affinitive for macrophages that express abundant mannose receptors, to conjugate alendronate (ALN), a bisphosphonate compound with in vitro macrophage-inhibiting activities. In both in vitro and in vivo tests, the prepared ALN-BSP conjugate could preferentially accumulate in macrophages and induced them into apoptosis. In the subcutaneous S180 tumour-bearing mice model, the treatment using ALN-BSP effectively eliminated TAMs, remarkably inhibited angiogenesis, recovered local immune surveillance, and eventually suppressed tumour progression, without eliciting any unwanted effect such as systematic immune response. Interestingly, ALN alone failed to exhibit any anti-TAM activity in vivo, probably because this compound was susceptible to the mildly acidic tumour microenvironment. Taken together, these results demonstrate the potential of ALN-BSP as a safe and efficient tool targeted at direct depletion of TAMs for cancer immunotherapy.     

An acid-labile temperature-responsive sol–gel reversible polymer for enhanced gene delivery to the myocardium and skeletal muscle cells

The work demonstrates the development of acid-labile temperature-responsive sol–gel reversible polymer for enhanced in vivo myocardium and skeletal muscle gene delivery. In this report, multi-block copolymers (MBCPs) synthesized from pluronic^® and di-(ethylene glycol) divinyl ether (DEGDVE) were used as a delivery vehicle for controlled and sustained release of plasmid DNA (pDNA) in in vitro as well as in vivo experiments. The non-ionic MBCP/pDNA complex showed remarkable transfection efficiencies against the myocardium cells as well as muscle cells in vivo, which is otherwise very difficult to achieve by using cationic polymers. In in vitro experimental settings, this intelligent stimuli-responsive polymer is shown to improve the transfection efficiency of branched polyethylenimine (BPEI)/pDNA complex when used together. The effect of MBCP on the surface charge and particle size of its various complexes with pDNA and BPEI was also studied. The release profile of pDNA from the MBCP gel was investigated and pH of the degraded polymer was also monitored to ascertain its non-cytotoxicity arising due to the increased acidity as observed with other PLGA-based polymers. The rapid sol–gel transition of MBCP under thermal stimuli with concomitant release of pDNA under acidic stimulation has potential for site specific, efficient and controlled transfection of therapeutic gene. In short, MBCP provides the silver lining in combat against the hurdles encountered in transfection to myocardial or other muscle cells.     

Structure–transfection activity relationships with glucocorticoid–polyethyl-enimine conjugate nuclear gene delivery systems

Efficient nuclear gene delivery is essential for successful gene therapy. It was previously reported that the transport of DNA into nucleus may be facilitated by glucocorticoid (GC). In this study, five glucocorticoids with different structures and potencies were conjugated with low molecular weight PEI 1800, and the degree of substitution of glucocorticoids was controlled to be close to each other. The glucocorticoid–polyethylenimine (GC–PEI)/pDNA complexes were prepared and their physico-chemical properties and transfection efficiency were investigated. The results showed that the complexes had similar physico-chemical properties, but their transfection activities were different statistically. In order to explore the reason of this difference, the affinity of GC–PEI polymer with GC receptor was analyzed by the application of molecular docking, and the correlation between transfection activity and the potency of five GC was investigated. The result showed that receptor binding of five GC was different and transgene expression enhanced linearly with the increasing GC potency, but log P. In addition, confocal microscopy examination confirmed that GC–PEI/DNA complexes were more effectively translocated in the nucleus than PEI 25 K or PEI 1800 complexes and the cytotoxicities of the GC–PEI polymers were lower than that of PEI 25 K. These results demonstrated that transfection activity of GC–PEI polymer correlated with its GC potency, and this regularity might be useful for the development of more efficient GC substituted polymer as promising nuclear-targeting carrier.     

5-Fluorouracil–lipid conjugate: Potential candidate for drug delivery through encapsulation in hydrophobic polyester-based nanoparticles

The encapsulation of 5-fluorouracil (5-FU) in hydrophobic polymeric materials is made feasible by a lipid-based prodrug approach. A lipid–5-FU conjugate of 5-FU with palmitic acid was synthesized in two-step process. A synthesized dipalmitoyl derivative (5-FUDIPAL) was characterized using Fourier transform infrared spectroscopy and ¹H-nuclear magnetic resonance. The 5-FUDIPAL was encapsulated in polyester-based polymers by the double emulsion–solvent evaporation method. The nanoparticles were characterized by scanning electron microscopy, transmission electron microscopy and dynamic light scattering. The thermal stability was assessed by differential scanning calorimetry data. In vitro release kinetics measurements of the drug from nanoparticles showed the controlled release pattern over a period of time. Cytotoxicity measurements by MTT assay confirmed that dipalmitoyl derivative in nano formulation successfully inhibited the cell growth. Thus the combined physical and biological evaluation of the different polyester-based nanoparticle containing the modified drug showed a facile approach to delivering 5-FU to the tumour site with enhanced efficacy.     

Specific cell targeting with APRPG conjugated PEG–PLGA nanoparticles for treating ovarian cancer

Good biocompatibility, specific tumor targeting, effective drug loading capacity and persistence in the circulation in vivo are imperative prerequisites for the antitumor efficiency of nanoparticles and their further clinical application. In this study, APRPG (Ala-Pro-Arg-Pro-Gly) peptide-modified poly (ethylene glycol)–poly (lactic acid) (PEG–PLA) nanoparticles (NP-APRPG) encapsulating inhibitors of angiogenesis (TNP-470) (TNP-470-NP-APRPG) were fabricated. TNP-470-NP-APRPG was designed to feature maleimide-PEG–PLA and mPEG–PLA as carrier materials, the APRPG peptide for targeting angiogenesis, PEG for prolonging circulation in vivo and PLA for loading TNP-470. TNP-470-NP-APRPG was confirmed to be approximately 130 nm in size with negative ζ-potential (−14.3 mV), narrow distribution (PDI = 0.27) and spherical morphology according to dynamic light scattering (DLS) and transmission electron microscopy (TEM) analyses. In addition, X-ray photoelectron spectra (XPS) analyses confirmed 7.73% APRPG grafting on the TNP-470-NP. In vitro, TNP-470-NP-APRPG exhibited effective inhibition of proliferation, migration and tube formation in human umbilical vein endothelial cells (HUVECs). Similar findings were observed for the retardation of tumor growth in SKOV3 ovarian cancer-bearing mice, suggesting the significant inhibition of angiogenesis and antitumor efficiency of TNP-470-NP-APRPG. Moreover, no obvious toxic drug responses were observed. Further evidence obtained from the immunohistochemical examination demonstrated that the tumor growth inhibition was closely correlated with the high rate of apoptosis among endothelial cells and the effective blockade of endothelial cell proliferation. These results demonstrate that NP-APRPG is a promising carrier for delivering TNP-470 to treat ovarian cancer and that this approach has the potential to achieve broad tumor coverage in the clinic.     

Self-assembled pH-responsive hyaluronic acid–g-poly(l-histidine) copolymer micelles for targeted intracellular delivery of doxorubicin

Hyaluronic acid (HA) was conjugated with hydrophobic poly(l-histidine) (PHis) to prepare a pH-responsive and tumor-targeted copolymer, hyaluronic acid–g-poly(l-histidine) (HA-PHis), for use as a carrier for anti-cancer drugs. The effect of the degree of substitution (DS) on the pH-responsive behaviour of HA-PHis copolymer micelles was confirmed by studies of particles of different sizes. In vitro drug release studies demonstrated that doxorubicin (DOX) was released from HA-PHis micelles in a pH-dependent manner. In vitro cytotoxicity assays showed that all the blank micelles were nontoxic. However, MTT assay against Michigan Cancer Foundation-7 (MCF-7) cells (overexpressed CD44 receptors) showed that DOX-loaded micelles with a low PHis DS were highly cytotoxic. Cellular uptake experiments revealed that these pH-responsive HA-PHis micelles taken up in great amounts by receptor-mediated endocytosis and DOX were efficiently delivered into cytosol. Moreover, micelles with the lowest DS exhibited the highest degree of cellular uptake, which indicated that the micelles were internalized into cells via CD44 receptor-mediated endocytosis and the carboxylic groups of HA are the active binding sites for CD44 receptors. Endocytosis inhibition experiments and confocal images demonstrated that HA-PHis micelles were internalized into cells mainly via clathrin-mediated endocytosis and delivered to lysosomes, triggering release of DOX into the cytoplasm. These results confirm that the biocompatible pH-responsive HA-PHis micelles are a promising nanosystem for the intracellular targeted delivery of DOX.     

PEG–PCL based micelle hydrogels as oral docetaxel delivery systems for breast cancer therapy

In this study, a composite drug delivery system was developed and evaluated for oral delivery of docetaxel: docetaxel-loaded micelles in pH-responsive hydrogel (DTX-micelle–hydrogel). Docetaxel was successfully loaded in micelles with small particle size of 20 nm and high drug loading of 7.76%, which contributed to the drug absorption in the intestinal tract. The experiments of cytotoxicity on 4T1 cells demonstrated the effective antitumor activity of DTX micelles. Meanwhile, a pH-responsive hydrogel was synthesized and optimized for incorporating the docetaxel micelles. The pH-responsiveness and reversibility of the hydrogel were investigated under the pH conditions of the gastrointestinal tract. Furthermore, the DTX-micelle–hydrogel system showed much quicker diffusion of micelles in simulated intestinal fluid than in simulated gastric fluid, which was mainly caused by the change of pH value. The docetaxel released from the micelle–hydrogel system quite slowly, so it had little influence on the absorption of DTX micelles in small intestine. More important, the pharmacokinetic study revealed that the DTX-micelle–hydrogel significantly improved the oral bioavailability of docetaxel (75.6%) about 10 times compared to DTX micelles, and this increase in bioavailability was probably due to the small intestine targeting release of the pH-responsive hydrogel. Consequently, the oral DTX-micelle–hydrogel system was effective in inhibiting tumor growth in subcutaneous 4T1 breast cancer model, and decreased systemic toxicity compared with intravenous treatment. The apoptosis cells in the immunofluorescent studies and the proliferation-positive cells in the immunohistochemical studies were also consistent with the results. Therefore, the DTX-micelle–hydrogel system might be a promising candidate oral drug for breast cancer therapy.     

Singularity in cancer causation: are breast and ovarian cancer each due to a single cause? Proposals for investigation

The cause of most cancers is unknown, appearing apparently sporadically in the population. Where causality is known, some have a single cause only. It is hypothesised that some cancers, currently of unknown cause, are due to a single cause. Databases relating to the aetiology and epidemiology of a number of selected cancers and to theories of cancer causation were systematically searched. Data review shows that some cancers have a single cause, even in all known settings; others have single causes in specific settings and different causes in alternative settings; others have multiple causes. It is further hypothesised that, particularly for breast and ovarian cancer, specific directed investigations might be successful in elucidating the aetiology if due to single cause. Such investigations should occur in groups of diseased subjects, non-diseased but at-risk subjects, and normal (control) populations. These investigations should include tests for trace elements, chemicals, antibodies to infective agents, and markers of inflammation. Systematic differences between groups might give strong clues to aetiology.     

Drug carrier systems based on collagen–alginate composite structures for improving the performance of GDNF-secreting HEK293 cells

Glial cell line-derived neurotrophic factor (GDNF) is a potent neurotrophic factor. Development of drug delivery technologies facilitating controlled release of GDNF is critical to applying GDNF in treating neurodegenerative diseases. We previously developed 3D collagen microspheres and demonstrated enhanced GDNF secretion after encapsulation of HEK293 cells, which were transduced to overexpress GDNF in these microspheres. However, the entrapped HEK293 cells were able to migrate out of the collagen microspheres, making it undesirable for clinical applications. In this report, we investigate two new carrier designs, namely collagen–alginate composite gel and collagen microspheres embedded in alginate gel in preventing cell leakage, maintaining cell growth and controlling GDNF secretion in the HEK293 cells. We demonstrated that inclusion of alginate gel in both designs is efficient in preventing cell leakage to the surrounding yet permitting the GDNF secretion, although the cellular growth rate is reduced in an alginate concentration dependent manner. Differential patterns of GDNF secretion in the two designs were demonstrated. The collagen–alginate composite gel maintains a more or less constant GDNF secretion over time while the collagen microspheres embedded in alginate gel continue to increase the secretion level of GDNF over time. This study contributes towards the development of cell-based GDNF delivery devices for the future therapeutics of neurodegenerative diseases.     

Altered uterine contractility in response to β-adrenoceptor agonists in ovarian cancer

We aimed to prospectively examine β-adrenoceptor-mediated uterine contractility in women suffering from gynecological malignancies. Myometrial specimens were obtained from non-pregnant women undergoing hysterectomy for benign gynecological disorders, and ovarian, endometrial, synchronous ovarian–endometrial, and cervical cancer. Contractions of myometrial strips in an organ bath before and after cumulative dosages of β₂- and β₃-adrenoceptor agonists with preincubation of propranolol, SR 59230A, and butoxamine were studied. All agonists induced a dose-dependent attenuation for uterine contractility in endometrial or cervical cancer, similar to that observed in the reference group. Contradictory effects were observed for ovarian cancer alone or in combination with endometrial cancer. CL 316243 or ritodrine abolished the relaxation, whereas BRL 37344 increased the uterine contractility in ovarian cancer. Moreover, β-adrenoceptor antagonists caused varied effects for β₂- or β₃-adrenoceptor agonists. Our experiments demonstrate that ovarian cancer, alone or as synchronous ovarian–endometrial cancer, substantially alters uterine contractility in response to β-adrenoceptor agonists.