scholarly journals In vitro Evaluation of Antibacterial, Cytotoxic and Adherence Studies of Selected Commercial Probiotics

2020 ◽  
Vol 14 (3) ◽  
pp. 2085-2091
Author(s):  
Kolli Guna Ranjan ◽  
Girija Sankar G. ◽  
D.V.V. Satyanarayana Raju

There is increasing scientific evidence and commercial interest for using probiotics for eliminating and handling of specific diseases. Probiotics can be evaluated for its role and performance against isolated pathogens from contaminating sources. The present work reports on invitro antimicrobial activity of commercial selected probiotics against pathogenic microbe Vibrio parahaemolyticus. The work also describes cytotoxic activities using MTT assay and adherence studies of selected probiotics. Results for the studies showed maximum zone of inhibition 13.66±0.46mm in probiotic enteroplus,12.33±0.93mm in lactobacillus (NCIM2056) and 10.66±0.93mm in Avant Bact. Cytotoxicity was expressed as IC50(µg/ml) values, observed on CaCO cell lines for different probiotics. Avant Bact showed a IC50 value of 104.7745, Lactobacillus (NCIM2056) a value of 58.13223 and Enteroplus a value of 50.09716. These values expressed different safety aspects of probiotics used for study. Finally the adherence study was done to check probiotic colonizing capacity. The probiotics showed varied adherence capacity against caco cell lines. Enteroplus has % adhesion of 10.25±0.74, Avant Bact. 7.25±0.82 and Lactobacillus (NCIM2056) 7.5±1.12. In conclusion antimicrobial results show importance of probiotics to be used against specific gastro intestinal diseases. Cytotoxicity determines safety aspects of probiotics and adherence study determines probiotic as a promising candidate for in vivo studies.

Cancers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 3487
Author(s):  
Yu-Ling Lu ◽  
Ming-Hsien Wu ◽  
Yi-Yin Lee ◽  
Ting-Chao Chou ◽  
Richard J. Wong ◽  
...  

Differentiated thyroid cancer (DTC) patients are usually known for their excellent prognoses. However, some patients with DTC develop refractory disease and require novel therapies with different therapeutic mechanisms. Targeting Wee1 with adavosertib has emerged as a novel strategy for cancer therapy. We determined the effects of adavosertib in four DTC cell lines. Adavosertib induces cell growth inhibition in a dose-dependent fashion. Cell cycle analyses revealed that cells were accumulated in the G2/M phase and apoptosis was induced by adavosertib in the four DTC tumor cell lines. The sensitivity of adavosertib correlated with baseline Wee1 expression. In vivo studies showed that adavosertib significantly inhibited the xenograft growth of papillary and follicular thyroid cancer tumor models. Adavosertib therapy, combined with dabrafenib and trametinib, had strong synergism in vitro, and revealed robust tumor growth suppression in vivo in a xenograft model of papillary thyroid cancer harboring mutant BRAFV600E, without appreciable toxicity. Furthermore, combination of adavosertib with lenvatinib was more effective than either agent alone in a xenograft model of follicular thyroid cancer. These results show that adavosertib has the potential in treating DTC.


2018 ◽  
Vol 48 (6) ◽  
pp. 2286-2301 ◽  
Author(s):  
Dijiong  Wu ◽  
Keding Shao ◽  
Qihao Zhou ◽  
Jie Sun ◽  
Ziqi Wang ◽  
...  

Background/Aims: Although the cure rate of acute promyelocytic leukemia (APL) has exceeded 90%, the relapse/refractory APL that resistant to all-trans retinoic acid (ATRA) or ATO was still serious concern. Matrine (MAT) could improve the differentiation ability of ATRA-resistant APL cells. This study aimed to explore how the APL-specific fusion protein was degraded in ATRA-resistant APL with the application of MAT and ATRA. Methods: ATRA-sensitive (NB4) and ATRA-resistant (NB4-LR1) cell lines were used. Nitroblue tetrazolium reduction assay and flow cytometry were used to detect the differentiation ability. The activity of ubiquitin-proteasome and autophagy-mediated pathways in both cells treated with ATRA with or without MAT were compared in protein and mRNA level (Western blot analysis, qRT-PCR), the Fluorescent substrate Suc-LLVY-AMC detection was used to detect the activity of proteasome, and electron microscope for observing autophagosome. MG 132(proteasome inhibitor), rapamycin (autophagy activator), hydroxychloroquine (lysosomal inhibitor) and STI571 [retinoic acid receptor alpha (RARα) ubiquitin stabilizer] were used as positive controls. The effect of MAT was observed in vivo using xenografts. Results: MAT improved the sensitivity of NB4-LR1cells to ATRA treatment, which was consistent with the expression of PML-RARα fusion protein. MAT promoted the ubiquitylation level in NB4-LR1. MG 132 induced the decrease in RARα in both cell lines, and hampered the differentiation of NB4 cells. MAT also promoted the autophagy in NB4-LR1 cells, with an increase in microtubule-associated protein 1 light chain3 (LC3)-II and LC3-II/LC3-I ratio and exhaustion of P62. The expression of LC3II increased significantly in the MAT and ATRA + MAT groups in combination with lysosomal inhibitors. A similar phenomenon was observed in mouse xenografts. MAT induced apoptosis and differentiation. Conclusions: Autophagy and ubiquitin-mediated proteolytic degradation of PML/RARα fusion protein are crucial in MAT-induced differentiation sensitivity recovery of NB4-LR1 cells.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 45-45
Author(s):  
Sushanth Gouni ◽  
Paolo Strati ◽  
Jason Westin ◽  
Loretta J. Nastoupil ◽  
Raphael E Steiner ◽  
...  

Background: Pre-clinical studies show that statins may improve the efficacy of chemoimmunotherapy in patients with DLBCL, through interference with cell membrane-initiated signaling pathways. Clinical retrospective studies, however, yield conflicting data, due to heterogeneous properties of statins, including potency and hydrophilicity. Methods: This is a retrospective analysis of patients with previously untreated, advanced stage DLBCL, non-double hit, treated with frontline R-CHOP between 01/01/2000 and 09/01/2019 (data cut-off 04/15/2020) at MD Anderson Cancer Center, and for whom data regarding statin use at time of initiation of treatment were available. Lugano 2014 response criteria were applied retrospectively for response assessment. Cellular cholesterol levels were analyzed in 6 DLBCL cell lines using an Amplex red fluorometric assay. A doxorubicin (DXR)-resistant cell line was generated exposing SUDHL4 cells to escalating doses of DXR; a DXR-resistant DLBCL patient-derived xenograft (PDX) model was established through serial transplantation and exposure to DXR. Results: 271 patients were included in the analysis, 182 (67%) were older than 60 years, 134 (49%) were male, 212 (72%) had stage IV disease, and 217 (80%) had an IPI score > 3; upon pathological review, 38 (36%) cases were non-GCB type, and 18 (28%) were double-expressors; 214 (79%) were able to complete all planned 6 cycles of RCHOP. Seventy-nine (29%) patients received statins at time of initiation of chemoimmunotherapy: 15 patients received low potency statin, 51 medium and 13 high; 18 patients received hydrophilic statins and 61 lipophilic. Patients receiving statins were significantly older as compared to patients who did not (p<0.001); no other significant difference in baseline characteristics was observed when comparing the 2 groups. Overall, 265 out of 271 patients were evaluable for response, as 6 stopped treatment because of toxicity before first response assessment. Among these, ORR was 95% (252/265) and CR rate was 62% (165/265). ORR rate was identical in patients who were treated with statin and those who did not (95% both, p=1). After a median follow-up of 77 months (95% CI, 70-84 months), 119 patients progressed/died, median PFS was not reached and 6-year PFS was 57%. 6-year PFS rate according to statin intensity was: 48% (low), 72% (medium), 57% (high). PFS. 6-year PFS rate was 64% for hydrophilic and 72% for lipophilic statins. Patients treated with statins had a trend for longer PFS (p=0.06), significantly longer for patients receiving medium potency statins (p=0.04). No significant difference in PFS was observed when comparing patients treated with lipophilic statins to all others (not reached vs 84 months, p=0.22). To confirm these clinical data, in-vitro and in-vivo studies were performed. Six cell lines were tested: 4 with high cholesterol content (SUDHL4, HBL1, HT, and U2932; 5.0-8.0 µg/mg protein), and 2 with low cholesterol content (DOHH2 and OCI-LY19; 1.5-2.0 µg/mg protein); the latter showed the highest sensitivity to DXR-mediated killing. The combination of lovastatin and DXR (10nM) was tested in all 4 cell lines with high cholesterol content, resulting in more cell death than either treatment alone. Lovastatin (at the nanomolar range) resensitized DXR-resistant SUDHL4 cells to DXR. Finally, in a DXR-resistant PDX model, the combination of lovastatin and DXR resulted in delayed tumor growth as compared to chemotherapy alone. Conclusions: Use of medium potency statins is associated with improved outcomes after frontline RCHOP in patients with DLBCL. This was further confirmed in functional in-vitro and in-vivo studies. Future interventional studies, aimed at improving outcomes in these patients using this novel combination, are warranted. Disclosures Westin: Amgen: Consultancy; 47: Research Funding; Kite: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Morphosys: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Curis: Consultancy, Research Funding; Astra Zeneca: Consultancy, Research Funding. Nastoupil:Gamida Cell: Honoraria; Merck: Research Funding; TG Therapeutics: Honoraria, Research Funding; Karus Therapeutics: Research Funding; Janssen: Honoraria, Research Funding; LAM Therapeutics: Research Funding; Novartis: Honoraria, Research Funding; Bayer: Honoraria; Celgene: Honoraria, Research Funding; Genentech, Inc.: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Gilead/KITE: Honoraria. Neelapu:Bristol-Myers Squibb: Other: personal fees, Research Funding; Merck: Other: personal fees, Research Funding; Kite, a Gilead Company: Other: personal fees, Research Funding; Pfizer: Other: personal fees; Celgene: Other: personal fees, Research Funding; Novartis: Other: personal fees; Karus Therapeutics: Research Funding; N/A: Other; Takeda Pharmaceuticals: Patents & Royalties; Acerta: Research Funding; Cellectis: Research Funding; Poseida: Research Funding; Precision Biosciences: Other: personal fees, Research Funding; Legend Biotech: Other; Adicet Bio: Other; Allogene Therapeutics: Other: personal fees, Research Funding; Cell Medica/Kuur: Other: personal fees; Calibr: Other; Incyte: Other: personal fees; Unum Therapeutics: Other, Research Funding. Landgraf:NCI/NIH: Research Funding. Vega:NCI: Research Funding.


2019 ◽  
Vol 21 (Supplement_3) ◽  
pp. iii36-iii36
Author(s):  
V Laspidea ◽  
M Puigdelloses ◽  
M García-Moure ◽  
I Iñigo-Marco ◽  
J Gallego ◽  
...  

Abstract BACKGROUND Diffuse intrinsic pontine glioma (DIPG) is an aggressive brain tumor, being the leading cause of pediatric death caused by cancer. We previously showed that administration of the oncolytic virus Delta-24-RGD to DIPG murine models was safe and led to an increase in the median survival of these animals. However, not all the animals responded, underscoring the need to improve this therapy. In order to increase the antitumoral effect of the virus, we have engineered Delta-24-RGD with the costimulatory ligand 4-1BBL (Delta24-ACT). 4-1BB is a costimulatory receptor that promotes the survival and expansion of activated T cells, and the generation and maintenance of memory CD8+ T cells. In this project, we evaluated the oncolytic effect of Delta24-ACT and the antitumor immune response in DIPG murine models. MATERIALS AND METHODS We use the NP53 and XFM murine DIPG cell lines. Flow cytometry was used to assess cell infectivity and ligand expression. We analyzed viral replication using a method based in hexon detection, and viral cytotoxic effect using the MTS assay. For immunogenic cell death analysis, we measured ATP secretion by a luminometric assay and calreticulin location by flow cytometry and immunofluorescence. For in vivo studies, cells and virus were injected in the pons of the mice, using the screw-guided system. RESULTS In vitro, Delta24-ACT was able to infect and induce cell death in a dose-dependent manner in murine DIPG cell lines. In addition, Delta24-ACT was able to replicate in these tumor cells and to express viral proteins. Moreover, infected cells expressed 41BBL in their membranes. Delta24-ACT could induce immunogenic cell death due to an increased secretion of ATP and calreticulin translocation to the membrane of infected cells (in no-infected cells it located in the ER), DAMPs that can trigger the immune response activation. In vivo, Delta24-ACT demonstrated to be safe in all the tested doses and was able to induce a significant increase in the median survival of the treated animals. Moreover, long-term survivors display immunological memory. CONCLUSIONS Delta24-ACT treatment led to antitumoral effect in DIPG murine cell lines in vitro. Of significance, we have demonstrated that in vivo administration of Delta24-ACT is safe and results in an enhanced antitumor effect. Future in vivo studies will explore the underlying immune mechanism of the virus.


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Farzaneh Naghibi ◽  
Somayeh Esmaeili ◽  
Noor Rain Abdullah ◽  
Mehdi Nateghpour ◽  
Mahdieh Taghvai ◽  
...  

Based on the collected ethnobotanical data from the Traditional Medicine and Materia Medica Research Center (TMRC), Iran,Myrtus communisL. (myrtle) was selected for the assessment ofin vitroandin vivoantimalarial and cytotoxic activities. Methanolic extract of myrtle was prepared from the aerial parts and assessed for antiplasmodial activity, using the parasite lactate dehydrogenase (pLDH) assay against chloroquine-resistant (K1) and chloroquine-sensitive (3D7) strains ofPlasmodium falciparum. The 4-day suppressive test was employed to determine the parasitemia suppression of the myrtle extract againstP. berghei  in vivo. The IC50values of myrtle extract were 35.44 µg/ml against K1 and 0.87 µg/ml against 3D7. Myrtle extract showed a significant suppression of parasitaemia (84.8 ± 1.1% at 10 mg/kg/day) in mice infected withP. bergheiafter 4 days of treatment. Cytotoxic activity was carried out against mammalian cell lines using methyl thiazol tetrazolium (MTT) assay. No cytotoxic effect on mammalian cell lines up to 100 µg/mL was shown. The results support the traditional use of myrtle in malaria. Phytochemical investigation and understanding the mechanism of action would be in our upcoming project.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2467-2467
Author(s):  
Richard A. Campbell ◽  
Haiming Chen ◽  
Daocheng Zhu ◽  
Janice C. Santos ◽  
Benjamin Bonavida ◽  
...  

Abstract Arsenic trioxide (ATO) induces apoptosis of plasma cells through a number of mechanisms including inhibiting DNA binding by NF-κB. These results suggest that this agent may be synergistic when combined with other active anti-myeloma drugs. To evaluate this we examined the effect of ATO alone and in combination with anti-myeloma treatments evaluated in vitro with MTT assays and using our severe combined immunodeficient (SCID)-hu murine myeloma models. First, we determined the effects of combining ATO with bortezomib or melphalan on the myeloma cell lines RPMI8226 and U266. Cell proliferation assays demonstrated marked synergistic anti-proliferative effects of ATO at concentrations ranging from 5x10−5M – 5x10−9M and melphalan concentrations ranging from 3x10−5M – 3x10−9M. Similar effects were observed when these cell lines were treated with bortezomib and varying concentrations of ATO (5x10−5 M – 5x10−10 M). We also investigated the potential of ATO to increase the efficacy of anti-myeloma therapies in our SCID-hu murine model LAGλ–1 (Yang H et al. Blood 2002). Each SCID mouse was implanted with a 0.5 cm3 LAGλ–1 tumor fragment into the left hind limb muscle. Mice were treated with ATO alone at 6.0 mg/kg, 1.25 mg/kg, 0.25 mg/kg, and 0.05 mg/kg intraperitoneally (IP) daily x5/week starting 19 days post-implantation. Mice receiving the highest dose of ATO (6.0 mg/kg) showed marked inhibition of tumor growth and reduction of paraprotein levels while there was no effect observed in all other treatment groups. Next, 27 days following implantation of our LAGλ–1 intramuscular (IM) tumor, LAGλ–1 mice were treated with ATO (1.25 mg/kg) IP, bortezomib (0.25 mg/kg), or the combination of both drugs at these doses in the schedules outlined above. ATO or bortezomib treatment alone had no anti-myeloma effects at these low doses consistent with our previous results whereas there was a marked decrease in both tumor volume (57%) and paraprotein levels (53%) in mice receiving the combined therapy. The combination of melphalan and ATO was also evaluated in this model. LAGλ–1 bearing mice received therapy with melphalan IP x1/weekly at 12.0 mg/kg, 6.0 mg/kg, 0.6 mg/kg, and 0.06 mg/kg starting 22 days post-implantation and showed no anti-myeloma effects. Twenty-eight days following implantation of LAGλ–1 tumor, mice received ATO (1.25 mg/kg) or melphalan (0.6 mg/kg) alone at doses without anti-myeloma effects, or the combination of these agents at these doses. The animals treated with these drugs alone showed a similar growth and increase in paraprotein levels to control mice whereas the combination of ATO and melphalan at these low doses markedly suppressed the growth of the tumor by >50% and significantly reduced serum paraprotein levels. These in vitro and in vivo studies suggest that the addition of ATO to other anti-myeloma agents is likely to result in improved outcomes for patients with drug resistant myeloma. Based on these results, these combinations are now in clinical trials with promising early results for patients with drug resistant myeloma.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3345-3345
Author(s):  
Anargyros Xenocostas ◽  
Benjamin D Hedley ◽  
Jenny E Chu ◽  
D. George Ormond ◽  
Michel Beausoleil ◽  
...  

Abstract Abstract 3345 Background: Erythropoietin (EPO) is a key regulator of erythropoiesis, and has been shown to stimulate growth, maintain viability, and promote differentiation of red blood cell precursors. The EPO receptor (EPO-R) is expressed by erythroid cells and by several non-hematopoietic cell types including various neoplastic cells. Erythropoiesis-stimulating agents (ESAs) are used clinically for the treatment of chemotherapy-induced anemia. The results of some recent randomized clinical trials have reported an increased incidence in adverse events and reduced survival in ESA-treated metastatic breast cancer patients receiving chemotherapy, potentially related to EPO-induced cancer progression. These results have raised concerns over ESA treatment in metastatic cancer patients. However, very little pre-clinical data is available regarding the impact of EPO on breast cancer metastasis. The goal of the current study was therefore to determine if EPO can influence the malignant behavior of breast cancer cells and/or influence the metastatic process. Methods: MDA-MB-468, MDA-MB-231, MDA-MB-435, and 4T-1 breast cancer cell lines were treated with recombinant human EPO (rHuEPO; 10 U/ml) or control media and screened for EPO-R mRNA expression levels by RT-PCR, and for EPO-R protein expression by Western blot and flow cytometry. MDA-MB-231 (231) and MDA-MB-435 (435) cell lines were used for functional assays in vitro and in vivo. Untreated or rHuEPO treated cells were grown in 2D and 3D in vitro systems (standard tissue culture plates and 0.6% soft agar, respectively) to determine if rHuEPO influenced growth. In vitro cell survival was also assessed in response to treatment with rHuEPO in the presence or absence of paclitaxel chemotherapy (10mg/ml), radiation (10G), or hypoxic conditions (1% O2). Following mammary fat pad injection, in vivo effects of rHuEPO (300U/kg) alone or in combination with paclitaxel treatment (10mg/kg) were assessed in mouse models of tumorigenicity and spontaneous metastasis. Results: Expression analysis of EPO-R mRNA and protein revealed a large variation in levels across different cell lines. The majority of cell lines did not express cell surface EPO-R by flow cytometry, although two cell lines (231 and 435) did show weak expression of EPO-R mRNA, with only the 231 cell line showing EPO-R expression by Western blot. In vitro, a small protective effect from rHuEPO on radiation-treated 435 cells was seen (p<0.05); however, rHuEPO treatment alone or combined with chemotherapy or hypoxia did not cause a significant increase in cell survival relative to untreated controls cells. In contrast, in vivo studies demonstrated that rHuEPO increased the incidence and burden of lung metastases in immunocompromised mice injected with 231 or 435 cells and treated with paclitaxel relative to mice treated with paclitaxel alone (p<0.05). Conclusions: The lack of an in vitro effect of rHuEPO highlights the importance of in vivo studies to delineate the effects of EPO on the metastatic process. Our novel findings demonstrate that rHuEPO can reduce the efficacy of chemotherapy in the metastatic setting in vivo, and in some cases enhance the inherent metastatic growth potential of human breast cancer cells. This work was supported by funding from the London Regional Cancer Program and Janssen Ortho Canada Disclosures: Xenocostas: Janssen Ortho: Consultancy, Honoraria, Research Funding. Allan:Janssen Ortho: Research Funding.


2015 ◽  
Vol 33 (7_suppl) ◽  
pp. 205-205
Author(s):  
Thomas Nelius ◽  
Courtney Jarvis ◽  
Dalia Martinez-Marin ◽  
Stephanie Filleur

205 Background: Docetaxel/DTX and cabazitaxel/CBZ have shown promise in the treatment of metastatic Castration-Refractory Prostate Cancer/mCPRC however, comparative studies are missing. Toxicities of these drugs are significant, urging the need to modify taxane regimens. Recently, low-dose metronomic/LDM treatments using conventional chemotherapeutic drugs have shown benefits in CPRC in improving the effect of anti-angiogenic agents. Previously, we have demonstrated that LDM-DTX in combination with PEDF curbs significantly CRPC growth, limits metastases formation and prolongs survival in vivo. In this study, we intended to compare the cytotoxic effect of CBZ and DTX on CRPC cells in vitro and CL1 tumors in vivo. Methods: PC3, DU145 cell lines were from ATCC.CL1 cells were obtained from androgen-deprived LNCaP cells. Cell proliferation was assessed by crystal violet staining and cell cycle analyses. In vitro cytotoxicity assays were performed on CL1 cells/RAW264.7 macrophages co-cultures treated with PEDF and increasing doses of taxanes. For the in vivo studies, CL1 cells were engineered to stably express the DsRed Express protein +/- PEDF. PEDF anti-tumor effects were assessed on s.c. xenografts treated with DTX (5mg/kg ip ev. 4 day) as reference, CBZ (5mg/kg ip ev. 4 days, 1mg/kg for 10 days, 0.5mg/kg q.a.d. and 0.1mg/kg daily) or placebo. Results: CBZ limits cell proliferation with a greater efficacy than DTX in all CRPC cell lines tested. DU145 presented the largest difference. High doses of taxane blocked tumor cells in mitosis, whereas LDM increased the SubG1 population. This effect was significantly higher in DU145 cells treated with CBZ. In vivo, 5mg/kg CBZ delayed tumor growth more efficiently than 5mg/kg DTX. PEDF/5mg/kg CBZ markedly delayed tumor growth compared to all treatments. Finally, engulfment of tumor cells by macrophages was higher in combined treatments suggesting an inflammation-related process. Conclusions: CBZ is more efficient than DTX both in vitro and in vivo.The data also reinforce PEDF as a promising anti-neoplasic agent in combination with LDM taxane chemotherapies.


2020 ◽  
Vol 38 (15_suppl) ◽  
pp. e18108-e18108
Author(s):  
Michael Driscoll Toboni ◽  
Barbara Blachut ◽  
Mary M Mullen ◽  
Jo'an Tankou ◽  
Hollie M Noia ◽  
...  

e18108 Background: Evidence suggests DNA repair is a therapeutic target in endometrial cancer (EC). Given this, we determined whether combination therapy with AVB500, an AXL inhibitor, could improve response in a uterine serous cancer (USC) model. Methods: Two USC cell lines (ARK1 & ARK4) were treated with AVB500 (Aravive Biologics, Houston, TX) in combination with the poly ADP ribose polymerase (PARP) inhibitor, olaparib. Colony forming assays were assessed after 4 days of treatment with either AVB500 alone, olaparib alone or combination treatment (olaparib + AVB500); colonies were stained and absorbance was obtained to calculate relative cell viability using Graph Pad Prism. Baseline homologous recombination (HR) status was determined after radiating cells with 10Gy and identifying RAD51 foci by immunofluorescence (IF). Cell lines were considered to be HR proficient if over 30% of the cells expressed RAD51 ( > 5 foci per cell). IF was conducted using a Leica confocal microscope and foci were quantified using FociCounter. In vivo studies were performed using NOD-SCID mice injected with 1 x 107 ARK1 cells intraperitoneally followed by treatment q3 days for a 14 and 21 day treatment period. Treatment groups were vehicle control, AVB500 alone, olaparib alone and olaparib with AVB500. Results: The absorbance for olaparib + AVB500 was significantly less than the olaparib only group in two assays involving ARK1s (0.417nm vs 0.756nm, p = 0.001; 0.320nm vs 0.620nm, p = 0.008) as well as in ARK4s (0.186nm vs 0.641nm, p = 0.003). The HR assay indicated both cell lines were HR proficient. After baseline HR proficiency was established, the cell lines were pretreated with AVB500 prior to radiation. When compared to cells without treatment with AVB500, IF showed a decrease in RAD51 foci per cell in ARK1 (2.7 vs 7.3, p = 0.0003) and ARK4 (6.3 vs 13.0, p = 0.0054). The proportion of ARK1 cells expressing RAD51 decreased to 21%, indicating HR deficiency. Lastly, NOD-SCID mice receiving olaparib + AVB500 had less tumor weight than those treated with olaparib alone (0.008g vs 0.138g, p = 0.002) and AVB500 alone (0.008g vs 0.145g, p = 0.0006) in a 14 day and a 21 day treatment period (0.212g vs 0.586g, p = 0.027 and 0.212 vs 0.494g, p = 0.005, respectively). Conclusions: HR proficient USC cell lines treated in vitro and in vivo with the combination of AVB500 and olaparib demonstrate an improved response to olaparib or AVB500 alone with a greater decrease in tumor burden. AVB500 appears to induce HR deficiency. Additional therapeutic and mechanistic experiments are ongoing.


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