Anticancer Cell Effects Research Articles

Modulating the unfolded protein response with ISRIB mitigates cisplatin ototoxicity

Cisplatin is a commonly used chemotherapy agent with a nearly universal side effect of sensorineural hearing loss. The cellular mechanisms underlying cisplatin ototoxicity are poorly understood. Efforts in drug development to prevent or reverse cisplatin ototoxicity have largely focused on pathways of oxidative stress and apoptosis. An effective treatment for cisplatin ototoxicity, sodium thiosulfate (STS), while beneficial when used in standard risk hepatoblastoma, is associated with reduced survival in disseminated pediatric malignancy, highlighting the need for more specific drugs without potential tumor protective effects. The unfolded protein response (UPR) and endoplasmic reticulum (ER) stress pathways have been shown to be involved in the pathogenesis of noise-induced hearing loss and cochlear synaptopathy in vivo, and these pathways have been implicated broadly in cisplatin cytotoxicity. This study sought to determine whether the UPR can be targeted to prevent cisplatin ototoxicity. Neonatal cochlear cultures and HEK cells were exposed to cisplatin, and UPR marker gene expression and cell death measured. Treatment with ISRIB (Integrated Stress Response InhIBitor), a drug that activates eif2B and downregulates the pro-apoptotic PERK/CHOP pathway of the UPR, was tested for its ability to reduce apoptosis in HEK cells, hair-cell death in cochlear cultures, and hearing loss using an in vivo mouse model of cisplatin ototoxicity. Finally, to evaluate whether ISRIB might interfere with cisplatin chemoeffectiveness, we tested it in head and neck squamous cell carcinoma (HNSCC) cell-based assays of cisplatin cytotoxicity. Cisplatin exhibited a biphasic, non-linear dose–response of cell death and apoptosis that correlated with different patterns of UPR marker gene expression in HEK cells and cochlear cultures. ISRIB treatment protected against cisplatin-induced hearing loss and hair-cell death, but did not impact cisplatin’s cytotoxic effects on HNSCC cell viability, unlike STS. These findings demonstrate that targeting the pro-apoptotic PERK/CHOP pathway with ISRIB can mitigate cisplatin ototoxicity without reducing anti-cancer cell effects, suggesting that this may be a viable strategy for drug development.

Modulating the Unfolded Protein Response with ISRIB Mitigates Cisplatin Ototoxicity.

Cisplatin is a commonly used chemotherapy agent with a nearly universal side effect of sensorineural hearing loss. The cellular mechanisms underlying cisplatin ototoxicity are poorly understood. Efforts in drug development to prevent or reverse cisplatin ototoxicity have largely focused on pathways of oxidative stress and apoptosis. An effective treatment for cisplatin ototoxicity, sodium thiosulfate (STS), while beneficial when used in standard risk hepatoblastoma, is associated with reduced survival in disseminated pediatric malignancies, highlighting the need for more specific drugs without potential tumor protective effects. The unfolded protein response (UPR) and endoplasmic reticulum (ER) stress pathways have been shown to be involved in the pathogenesis of noise-induced hearing loss and cochlear synaptopathy in vivo, and these pathways have been implicated broadly in cisplatin cytotoxicity. This study sought to determine whether the UPR can be targeted to prevent cisplatin ototoxicity. Neonatal cochlear cultures and HEK cells were exposed to cisplatin and UPR-modulating drugs, and UPR marker gene expression and cell death measured. Treatment with ISRIB, a drug that activates eif2B and downregulates the pro-apoptotic PERK/CHOP pathway of the UPR, was tested in an in vivo mouse model of cisplatin ototoxicity and well as a head and neck squamous cell carcinoma (HNSCC) cell-based assay of cisplatin cytotoxicity. Cisplatin exhibited a biphasic, non-linear dose-response of cell death and apoptosis that correlated with different patterns of UPR marker gene expression in HEK cells and cochlear cultures. ISRIB treatment protected against cisplatin-induced hearing loss and hair-cell death, but did not impact the cytotoxic effects of cisplatin on HNSCC cell viability, unlike STS. These findings demonstrate that targeting the pro-apoptotic PERK/CHOP pathway with ISRIB can mitigate cisplatin ototoxicity without reducing anti-cancer cell effects, suggesting that this may be a viable strategy for drug development.

A High Catalytic Activity Nanozyme Based on Cobalt-Doped Carbon Dots for Biosensor and Anticancer Cell Effect

Nanozyme technology as an emerging field has been successfully applied to chemical sensing, biomedicine, and environmental monitoring. It is very significant for the advance of this field to construct nanozymes with high catalytic activity by a simple method and to develop their multifunctional applications. Here, a new type of cobalt-doped carbon dots (Co-CDs) nanozymes was designed using vitamin B12 and citric acid as the precursors. The homogeneous cobalt doping at carbon nuclear led the Co-CDs to show significant peroxidase-like activity resembling natural metalloenzymes. Based on the high affinity of Co-CDs to H2O2 (Km = 0.0598 mM), a colorimetric sensor for glucose detection was constructed by combining Co-CDs with glucose oxidase. On account of the high catalytic activity of nanozymes and the cascade strategy, a good linear relationship was obtained from 0.500 to 200 μM, with a detection limit of 0.145 μM. The biosensor has realized the accurate detection of glucose in human serum samples. Moreover, Co-CDs could specifically catalyze H2O2 in cancer cells to generate a variety of reactive oxygen species, leading to the death of cancer cells, which has useful application potential in tumor catalytic therapy. In this work, the catalytic activity of Co-CDs has been adequately exploited, which extends the application of carbon dots in multiple biotechnologies, including biosensing, disease diagnosis, and treatment.

Radiofrequency Electromagnetic Fields Cause Non-Temperature-Induced Physical and Biological Effects in Cancer Cells.

Non-temperature-induced effects of radiofrequency electromagnetic fields (RF) have been controversial for decades. Here, we established measurement techniques to prove their existence by investigating energy deposition in tumor cells under RF exposure and upon adding amplitude modulation (AM) (AMRF). Using a preclinical device LabEHY-200 with a novel in vitro applicator, we analyzed the power deposition and system parameters for five human colorectal cancer cell lines and measured the apoptosis rates in vitro and tumor growth inhibition in vivo in comparison to water bath heating. We showed enhanced anticancer effects of RF and AMRF in vitro and in vivo and verified the non-temperature-induced origin of the effects. Furthermore, apoptotic enhancement by AM was correlated with cell membrane stiffness. Our findings not only provide a strategy to significantly enhance non-temperature-induced anticancer cell effects in vitro and in vivo but also provide a perspective for a potentially more effective tumor therapy.

Discharge characteristics of a microsecond pulse power supply driven air plasma jet and its anticancer cell effect

In plasma cancer therapy, atmospheric pressure plasma jets have attracted increasing attention in recent years. In this study, from the point of view of economic costs and portability, we have employed atmospheric air as the working gas in order to investigate the effects of the rate of flow, applied voltage, frequency, and pulse width on the characteristics of discharge. The concentrations of reactive oxygen and nitrogen species (RONS) in a plasma-activated medium (PAM) were characterized in order to explore their chemical activity. In addition, the inactivating effect of tumor cells induced by an air plasma jet was investigated and the corresponding inactivation mechanism is also discussed. The results showed that the discharge intensity was positively correlated with frequency and voltage, and negatively correlated with pulse width. Regarding the gas flow rate, when the air flow rate was 1 standard liter per minute (SLM), the discharge intensity was strongest according to the length of the plume. By summarizing the discharge characteristics and emission spectra under different experimental parameters, the stable treatment conditions producing rich active substances were as follows: a frequency of 6 kHz, a voltage of 14 kV, a gas flow rate of 1 SLM, and a pulse width of 1 μs. Furthermore, under these stabilized conditions, the air plasma jet produced rich aqueous RONS in a PAM effectively, which killed cells in significant numbers and reduced the cell survival rate. Therefore, this study demonstrates the potential application of an atmospheric PAM for the treatment of tumor cells and promotes a deeper understanding of plasma liquid chemistry.

Multifunctional Green Synthetic Hematite (α-Fe2O3) Nanoparticles Mediated by Camellia Sinensis (Indian Tea Plant) Extracts towards Antioxidant and Antiproliferative Activities against MCF-7 Cell Lines

Among nanoparticles used for medical applications, Camellia Sinensis Nanoparticles (CSNPs) are among the least investigated. This study was undertaken to develop CSNPs by green synthesis using Camellia sinensis tea (Theaceae) plant extract to produce the NPs. The Camellia sinensis, Indian tea plant used from ancient time to increase appetite. Other medicinal uses have also been employed for the synthesis of super paramagnetic α Fe2O3 nanoparticles (NPs). The plant extracts revealed the phenolic groups bifunctional nature and capping nature through the –OH bonding over the nanoparticles (NPs) surface. The prepared nanoparticles (NPs) shows α-Fe2O3 phase among iron oxides and spherical morphology with an average size around 5 nm. The magnetic measurements proved the superparamagnetic behaviour of NPs with non-saturating MS value of 8.5 emu/g at room temperature (300 K). The CSNPs were characterized by UV-V is spectroscopy and X-ray Diffractometry, and evaluated with Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR). The CSNPs were spherical (size 7-20 nm) and contained phenols and flavonoids acquired from the Camellia sinensis extract. CSNPs has good 1-Diphenyl-2-Picrylhydrazyl (DPPH), OH, and NO scavenging properties. MTT assay showed that CSNPs (IC50 = 0.006 μM) were more antiproliferative toward the human MCF-7 cells than the Camellia sinensis tea extract (IC50 = 0.894 μM), Gemcitabin (IC50 = 2.133 μM). The anticancer cell effects of CSNPs on MCF 7 are mediated through the induction of apoptosis and G2/M cell-cycle arrest.

Compound C enhances the anticancer effect of aspirin in HER-2-positive breast cancer by regulating lipid metabolism in an AMPK-independent pathway.

Various clinical studies have determined that aspirin shows anticancer effects in many human malignant cancers, including human epidermal growth factor receptor-2 (HER-2)-positive breast cancer. However, the anti-tumor mechanism of aspirin has not been fully defined. The aim of this study was to determine the role of Compound C in enhancing the anticancer effect of aspirin. HER-2-positive breast cancer cell lines were treated with aspirin with or without Compound C pre-treatment; their phenotypes and mechanisms were then analyzed in vitro and in vivo. Aspirin exhibited anticancer effects in HER-2-positive breast cancer by inhibiting cell growth and inducing apoptosis through the activation of AMP-activated protein kinase (AMPK). Unexpectedly, pre-treatment with Compound C, a widely used AMPK inhibitor, induced robust anticancer effects in cells compared to aspirin monotherapy. This anticancer effect was not distinct in HER-2 negative breast cancer MDA-MB-231 cells and may be due to the inhibition of lipid metabolism mediated by c-myc. Besides, c-myc re-expression or palmitic acid supply could partially restored cell proliferation. Aspirin exhibits anticancer effects in HER-2-positive breast cancer by regulating lipid metabolism mediated by c-myc, and Compound C strengthens these effects in an AMPK-independent manner. Our results potentially provide a novel therapeutic strategy exploiting combined aspirin and Compound C therapy for HER-2-positive breast cancer, which acts by reducing de novo lipid synthesis.

Doxorubicin-Loaded Delta Inulin Conjugates for Controlled and Targeted Drug Delivery: Development, Characterization, and In Vitro Evaluation.

Delta inulin, also known as microparticulate inulin (MPI), was modified by covalently attaching doxorubicin to its nanostructured surface for use as a targeted drug delivery vehicle. MPI is readily endocytosed by monocytes, macrophages, and dendritic cells and in this study, we sought to utilize this property to develop a system to target anti-cancer drugs to lymphoid organs. We investigated, therefore, whether MPI could be used as a vehicle to deliver doxorubicin selectively, thereby reducing the toxicity of this antibiotic anthracycline drug. Doxorubicin was covalently attached to the surface of MPI using an acid–labile linkage to enable pH-controlled release. The MPI-doxorubicin conjugate was characterized using FTIR and SEM, confirming covalent attachment and indicating doxorubicin coupling had no obvious impact on the physical nanostructure, integrity, and cellular uptake of the MPI particles. To simulate the stability of the MPI-doxorubicin in vivo, it was stored in artificial lysosomal fluid (ALF, pH 4.5). Although the MPI-doxorubicin particles were still visible after 165 days in ALF, 53% of glycosidic bonds in the inulin particles were hydrolyzed within 12 days in ALF, reflected by the release of free glucose into solution. By contrast, the fructosidic bonds were much more stable. Drug release studies of the MPI-doxorubicin in vitro, demonstrated a successful pH-dependent controlled release effect. Confocal laser scanning microscopy studies and flow cytometric analysis confirmed that when incubated with live cells, MPI-doxorubicin was efficiently internalized by immune cells. An assay of cell metabolic activity demonstrated that the MPI carrier alone had no toxic effects on RAW 264.7 murine monocyte/macrophage-like cells, but exhibited anti-cancer effects against HCT116 human colon cancer cells. MPI-doxorubicin had a greater anti-cancer cell effect than free doxorubicin, particularly when at lower concentrations, suggesting a drug-sparing effect. This study establishes that MPI can be successfully modified with doxorubicin for chemotherapeutic drug delivery.

Abstract IA22: Autoimmune rheumatic diseases and cancer

Abstract Some rheumatic disease autoantibodies are powerful markers of subgroups of patients who have distinct disease phenotypes and trajectories. Of particular interest are markers of several disease subgroups in whom cancer and rheumatic disease onset are clustered together in time. For example, a subgroup of scleroderma patients have coincident onset of cancer and scleroderma. This is observed in scleroderma patients with autoantibodies against RNA polymerase-3 (POLR3), and more recently with autoantibodies recognizing the minor spliceosome. In autoimmune myopathies, temporal clustering of diagnosis of cancer and myositis is associated with autoantibodies to NXP2 and components of the TIF1 complex. Interestingly, although the incidence of cancer is higher in patients with these autoantibodies, most patients with these autoantibodies do not manifest cancer, even with extended periods of follow-up. These observations provide an important opportunity to investigate the potential mechanisms which operate at the cancer-immune interface during development of rheumatic diseases. In cancers from anti-POLR3-positive scleroderma patients with a short scleroderma-cancer interval, we found genetic alterations of the POLR3A locus in six of eight patients with antibodies to POLR3 but not in eight patients without these antibodies. 3 antibody-positive patients had somatic mutations in POLR3A; 5 patients had loss of heterozygosity at the POLR3A locus. Analyses of peripheral blood lymphocytes and serum suggested that POLR3A mutations sparked cellular immunity and cross-reactive humoral immune responses. In a larger scleroderma cohort (>2300 patients), the incidence of cancer in various autoantibody subgroups was compared to data from the Surveillance, Epidemiology and End Results (SEER) Program. An increase in cancer incidence in scleroderma patients with POLR3 autoantibodies was observed compared to the general population; strikingly, patients with anti-centromere autoantibodies had a lower cancer incidence than observed in the general population. The finding that distinct serologic subgroups have different cancer risks suggests that cancer immunity may be a common principle across the scleroderma spectrum, with cancer emergence influenced by the effectiveness of the different immune responses. For example, in scleroderma patients with anti-centromere antibodies, cancer emergence may be inhibited, while inhibition of cancer emergence may only be partial for anti-POLR3. Prior studies in small cohorts of breast cancer patients have demonstrated that anti-centromere antibodies may be present, and may associate with improved disease-free and overall survival. Additionally, recent data also suggest that anti-DNA antibodies can have direct anti-cancer effects in cells with DNA repair defects, possibly explaining the decreased risk of breast and other cancers observed among patients with SLE.Taken together, these data suggest that at least some patients with autoimmune rheumatic diseases such as scleroderma may represent natural cancer immunoediting in humans. In the simplest model, somatic mutations in autoantigens in different cancers initiate an immune response to the mutated autoantigen, which spreads to include the wild type version, and exerts both an anti-cancer effect as well as causes damage or dysfunction of normal tissues. Understanding the mechanisms underlying the range of efficacies of the anti-cancer effects in different patients and subgroups may provide important insights into how the anti-cancer immune response in autoimmune diseases might be more effectively harnessed therapeutically. Citation Format: Livia Casciola-Rosen, Ami Shah, Antony Rosen. Autoimmune rheumatic diseases and cancer [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr IA22.

English

Clausenidin is a pyranocoumarin majorly found in medicinal herbs of the Rutaceae family used to treat cancer patients locally in Asia. The compound is presumed to have anti-cancer cell effect but its exact mechanism of action is still unknown. The study aimed to evaluate the effect of pure clausenidin on p53-mediated apoptosis as well as other cell death pathways in colon cancer (HT-29) cell lines. The anti-proliferative effect of clausenidin by cell cycle and annexin V assay using flow cytometry was evaluated. Morphological analysis of the treated cells was performed using scanning and transmission electron microscopy. Furthermore, the effect of p53 mRNA on cell cycle and apoptosis-related genes and proteins in clausenidin-treated HT-29 cells was investigated using qPCR and Western blot assays, respectively. Clausenidin induced a p53 dependent G0/G1 cell cycle arrest in HT-29 cells. It was also observed that the anti-cancer cell effect of clausenidin occurred via p53 mediated activation of p21, bax and transrepression of survivin and bcl 2 that culminated in the apoptosis of colon cancer cells. The transmission electron microscopy (TEM) micrographs confirmed the occurrence of apoptosis in clausenidin-treated HT-29 cells. Clausenidin is a potent anti-HT-29 cell agent that can be used to treat colon tumors. Key words: Clausenidin, p53, p21, apoptosis, cell cycle.

Green synthesis palladium nanoparticles mediated by white tea (Camellia sinensis) extract with antioxidant, antibacterial, and antiproliferative activities toward the human leukemia (MOLT-4) cell line.

Among nanoparticles used for medical applications, palladium nanoparticles (PdNPs) are among the least investigated. This study was undertaken to develop PdNPs by green synthesis using white tea (W.tea; Camellia sinensis) extract to produce the Pd@W.tea NPs. The Pd@W.tea NPs were characterized by UV–vis spectroscopy and X-ray diffractometry, and evaluated with transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The Pd@W.tea NPs were spherical (size 6–18 nm) and contained phenols and flavonoids acquired from the W.tea extract. Pd@W.tea NPs has good 1-diphenyl-2-picrylhydrazyl (DPPH), OH, and NO-scavenging properties as well as antibacterial effects toward Staphylococcus epidermidis and Escherichia coli. MTT assay showed that Pd@W.tea NPs (IC50 =0.006 μM) were more antiproliferative toward the human leukemia (MOLT-4) cells than the W.tea extract (IC50 =0.894 μM), doxorubicin (IC50 =2.133 μM), or cisplatin (IC50 =0.013 μM), whereas they were relatively innocuous for normal human fibroblast (HDF-a) cells. The anticancer cell effects of Pd@W.tea NPs are mediated through the induction of apoptosis and G2/M cell-cycle arrest.

Brassinin Combined with Capsaicin Enhances Apoptotic and Anti-metastatic Effects in PC-3 Human Prostate Cancer Cells.

Brassinin (BSN), a type of indole compound derived from cruciferous vegetables, has shown anti-cancer effects in cells and animals. Capsaicin (CAP), an alkaloid derived from the chilli pepper, is also of interest in for its reported efficacy against various malignancies. The objective of our study was to analyze the potential synergistic anti-tumor effects of BSN combined with CAP on prostate cancer PC-3 cells. After treatment with BSN and CAP at various concentrations, the synergistic cytotoxic effect of PC-3 cells was analyzed by MTT method, proliferation, apoptosis, mitochondrial membrane potential, colony formation, and Western blotting. Moreover, the inhibitory effects of BSN and CAP on the constitutive expressions of MMP-9/2, their enzymatic activities, cellular migration, and cell invasion were also investigated. The cytotoxicity was synergistically increased in combination compared with the single drug used; moreover, proliferation, apoptosis, mitochondrial membrane potential, and colony formation were significantly suppressed and anti-apoptotic-, proliferative-, and metastatic-related proteins were clearly abolished in the combination group. Besides, constitutive MMP-9/2 expression, their enzymatic activities, cell migration, and tumor cell invasion were inhibited, and TIMP-1 was up-regulated in the combination group in PC-3 cells. Our results indicate, for the first time, that BSN and CAP in combination exert synergistic anticancer effects in prostate carcinoma.

Hyperthermia Using Antibody-Conjugated Magnetic Nanoparticles and Its Enhanced Effect with Cryptotanshinone

Heat dissipation by magnetic nanoparticles (MNPs) under an alternating magnetic field can be used to selectively treat cancer tissues. Antibodies conjugated to MNPs can enhance the therapeutic effects of hyperthermia by altering antibody-antigen interactions. Fe3O4 nanoparticles (primary diameter, 20–30 nm) coated with polyethylenimine (PEI) were prepared and conjugated with CH11, an anti-Fas monoclonal antibody. HeLa cell growth was then evaluated as a function of antibody and MNP/antibody complex doses. HeLa cell growth decreased with increased doses of the antibody and complexes. However, MNPs alone did not affect cell growth; thus, only the antibody affected cell growth. In hyperthermia experiments conducted using an alternating magnetic field frequency of 210 kHz, cell viability varied with the intensity of the applied alternating magnetic field, because the temperature increase of the culture medium with added complexes was dependent on magnetic field intensity. The HeLa cell death rate with added complexes was significantly greater as compared with that with MNPs alone. Cryptotanshinone, an anti-apoptotic factor blocker, was also added to cell cultures, which provided an additional anti-cancer cell effect. Thus, an anti-cancer cell effect using a combination of magnetic hyperthermia, an anti-Fas antibody and cryptotanshinone was established.

Intravenous administration of Reolysin®, a live replication competent RNA virus is safe in patients with advanced solid tumors

Reolysin is reovirus serotype 3-Dearing strain, a double-stranded replication-competent RNA non-enveloped icosahedral virus. It induces cytopathic and anti-cancer effects in cells with an activated ras pathway due to inhibition of the dsRNA-activated protein kinase. This was a single center dose escalation trial of Reolysin administered intravenously every 4 weeks in doses ranging from 1 x 10(8) to 3 x 10(10) tissue culture infective dose (TCID)(50). Serum for neutralizing antibody, and serum, stool, saliva, and urine for viral shedding were collected. Tumor samples were analyzed for activating mutations in the ras and braf oncogenes. Eighteen patients received 27 doses of Reolysin in 6 dose cohorts accomplishing a 300 fold dose escalation without a protocol-defined dose limiting toxicity. Drug related grade 2 toxicities included fatigue and fever (1 patient each). All patients developed neutralizing antibody during the course of the study. Viral shedding was observed in 6 patients. One patient with anthracycline and taxane refractory breast cancer experienced a partial response (PR) and her tumor had a ras G12A mutation. Biopsy from her chest wall mass showed evidence of necrosis and viral replication by electron microscopy. Overall clinical benefit (1 PR + 7 stable disease) rate was 45%, and appeared higher in patients with viral shedding (67%) than those without (33%). Reolysin administered monthly as a one-hour infusion is safe and well-tolerated even in multiple doses. Reolysin has anti-tumor activity as a single agent warranting further evaluation, including in combination with chemotherapy. Viral shedding may suggest intrapatient replication yielding a benefit and should be studied carefully in future studies.

Dose escalation and pharmacodynamic study of intravenous adminstration of Reolysin, a live replication competent RNA virus in patients with advanced solid tumors

3583 Background: Reolysin is reovirus serotype 3 - Dearing strain, a double-stranded replication- competent RNA non-enveloped icosahedral virus. It induces cytopathic and anti-cancer effects in cells with an activating mutation in the ras proto-oncogene. Methods: This was a single center dose escalation trial of Reolysin administered intravenously every four weeks in doses ranging from 1X108 to 3X1010 tissue culture infective dose (TCID)50. Serum for neutralizing antibody, and serum, stool, saliva, and urine for viral shedding were collected. Tumor samples were analyzed for activating mutations in the ras and braf oncogenes. Results: Eighteen patients received 27 doses of Reolysin in 6 dose cohorts accomplishing a 300 fold dose escalation without a protocol-defined dose limiting toxicity. Drug related grade 2 toxicities included fatigue and fever (1 patient each). All patients developed neutralizing antibody during the course of the study. Viral shedding was observed in 6 patients [urine (5), serum (4), saliva (3), and stool (2)]. One patient with anthracycline and taxane refractory breast cancer experienced a partial response (PR) and her tumor had a mutation in the ras oncogene. Biopsy from a chest wall mass showed evidence of necrosis and viral replication by electron microscopy. The overall clinical benefit rate was 45% and appeared higher in patients with viral shedding (67%) than those without (33%). Conclusions: Reolysin administered as a one hour infusion on a monthly schedule is safe and well-tolerated even in multiple doses. Reolysin has anti-tumor activity as a single agent warranting further evaluation, including in combination with chemotherapy. Viral shedding may suggest intrapatient replication yielding a benefit and should be studied carefully in future studies. [Table: see text]

Activity of mevalonate pathway inhibitors against breast and ovarian cancers in the ATP-based tumour chemosensitivity assay

Previous data suggest that lipophilic statins such as fluvastatin and N-bisphosphonates such as zoledronic acid, both inhibitors of the mevalonate metabolic pathway, have anti-cancer effects in vitro and in patients. We have examined the effect of fluvastatin alone and in combination with zoledronic acid in the ATP-based tumour chemosensitivity assay (ATP-TCA) for effects on breast and ovarian cancer tumour-derived cells. Both zoledronic acid and fluvastatin showed activity in the ATP-TCA against breast and ovarian cancer, though fluvastatin alone was less active, particularly against breast cancer. The combination of zoledronic acid and fluvastatin was more active than either single agent in the ATP-TCA with some synergy against breast and ovarian cancer tumour-derived cells. Sequential drug experiments showed that pre-treatment of ovarian tumour cells with fluvastatin resulted in decreased sensitivity to zoledronic acid. Addition of mevalonate pathway components with zoledronic acid with or without fluvastatin showed little effect, while mevalonate did reduced inhibition due to fluvastatin. These data suggest that the combination of zoledronic acid and fluvastatin may have activity against breast and ovarian cancer based on direct anti-cancer cell effects. A clinical trial to test this is in preparation.