Combination Of Taxol Research Articles

Treatment of CHO cells with Taxol and reversine improves micronucleation and microcell-mediated chromosome transfer efficiency

Microcell-mediated chromosome transfer is an attractive technique for transferring chromosomes from donor cells to recipient cells and has enabled the generation of cell lines and humanized animal models that contain megabase-sized gene(s). However, improvements in chromosomal transfer efficiency are still needed to accelerate the production of these cells and animals. The chromosomal transfer protocol consists of micronucleation, microcell formation, and fusion of donor cells with recipient cells. We found that the combination of Taxol (paclitaxel) and reversine rather than the conventional reagent colcemid resulted in highly efficient micronucleation and substantially improved chromosomal transfer efficiency from Chinese hamster ovary donor cells to HT1080 and NIH3T3 recipient cells by up to 18.3- and 4.9-fold, respectively. Furthermore, chromosome transfer efficiency to human induced pluripotent stem cells, which rarely occurred with colcemid, was also clearly improved after Taxol and reversine treatment. These results might be related to Taxol increasing the number of spindle poles, leading to multinucleation and delaying mitosis, and reversine inducing mitotic slippage and decreasing the duration of mitosis. Here, we demonstrated that an alternative optimized protocol improved chromosome transfer efficiency into various cell lines. These data advance chromosomal engineering technology and the use of human artificial chromosomes in genetic and regenerative medical research.

Abstract 3285: Targeting STAT3 with novel liposome-incorporated antisense oligonucleotide technology enhances the efficacy of paclitaxel (taxol) and 5-fluorouracil (5-FU) in breast and ovarian cancer cells

Abstract Background: STAT3 is a transcription factor that regulates various tumorigenic processes, such as tumor proliferation, metastasis, and drug resistance. Its overexpression and aberrant activation characterize many cancers (including breast, lung, ovarian, liver and colon cancer). Metastasis and drug resistance are two main causes of patient mortality. Activation of the JAK-STAT3 and the FGFR1-STAT3 pathways in breast and ovarian cancer cells promotes tumor initiation, migration, and taxol resistance. STAT3 also contributes to epithelial-mesenchymal transition and promotes 5-FU resistance in colorectal cancer cells. Its role in numerous malignancies has made STAT3 an ideal cancer therapeutic target. BP1003 is a neutral DOPC liposome incorporated with a nuclease-resistant P-ethoxy antisense oligodeoxynucleotide targeting STAT3 mRNA. Here we determine the effects of BP1003 in combination with taxol and 5-FU on breast and ovarian cancer cells. Methods: Western blots determined the extent by which BP1003 reduced STAT3 protein levels. The effect of sequential taxol or 5-FU (5 h pre-treatment) and BP1003 treatments (96 h) on cell viability was analyzed with resazurin-based assays. Migration and colony formation assays were performed to assess the metastatic potential of treated cells. Cells pre-treated with BP1003 (96 h) and taxol (2 h) were placed in chemotaxis chambers and allowed to migrate for 5-18 h before quantification. Colony formation involved the treatment of a low number of cells with chemotherapeutic drugs for 24 h prior to the addition of BP1003 for 10-14 days. Tumor spheroids were used to mimic in vivo solid tumor growth. Three days after formation, spheroids were treated with chemotherapeutic drugs for 1 day before being treated with BP1003 for 3 additional days. Results: Treatment of BT549, SK-Br-3 and SK-Ov-3 cells with 250 μg/ml of BP1003 resulted in a 30%-50% decrease in STAT3 expression. Cell viability decreased by 20-35% with 200 μg/ml of BP1003 and by 45-60% in combination with taxol or 5-FU. BP1003 in combination with taxol also decreased the colony formation potential of BT549 cells by 20%. Migration of BT549 cells was reduced by 30% with 200 μg/ml BP1003 alone and by 50% in combination with taxol. The area of BT549 and SK-Ov-3 spheroids under BP1003 and taxol combination treatments was 40%-50% smaller than control spheroids and 20%-30% smaller than taxol mono-treatment. Conclusions: BP1003 efficiently reduces STAT3 expression and enhances the sensitivity of breast and ovarian cancer cells to taxol and 5-FU. These results are in line with previous work in which BP1003 + gemcitabine displayed enhanced anti-tumor activity in pancreatic ductal adenocarcinoma. Together these results strongly suggest that BP1003 combination therapy is a novel strategy for patients with advanced solid tumors. Citation Format: Maria Gagliardi, Ana Tari Ashizawa. Targeting STAT3 with novel liposome-incorporated antisense oligonucleotide technology enhances the efficacy of paclitaxel (taxol) and 5-fluorouracil (5-FU) in breast and ovarian cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3285.

Radix ranunculus temate saponins sensitizes ovarian cancer to Taxol via upregulation of miR-let-7b.

A common cause of treatment failure in ovarian cancer is acquired drug resistance. Therefore, effective novel drugs against chemoresistance need to be developed. MicroRNAs (miRNAs or miRs) serve key regulatory roles in tumorigenesis and chemoresistance. The objective of the present study was to explore the role of miR-let-7b in ovarian cancer chemoresistance, and to develop novel strategy for the treatment of drug-resistant ovarian cancer. For this purpose, reverse transcription-quantitative PCR was performed to evaluate the expression level of miR-let-7b in fresh ovarian cancer tissues and cell lines. miR-let-7b mimic was transfected into ovarian cancer cell lines. Functional experiments, cell apoptosis and cell viability assays were carried out to identify the tumor-suppressor function of miR-let-7b. The treatment effect of Radix ranunculus temate saponins (RRTS), one of the primary constituents extracted from the traditional Chinese medicine radix Ranunculi ternati, was identified in vitro and in vivo. The results revealed that miR-let-7b was downregulated significantly in chemoresistant ovarian cancer patients. miR-let-7b overexpression suppressed cell growth and invasion and enhanced sensitivity to Taxol of ovarian cancer cells. Furthermore, miR-let-7b levels in ovarian cancer tissue were inversely associated with collagen type III α1 chain (COL3A1) levels. COL3A1, a non-fibrillar collagen associated with chemoresistance, was targeted by miR-let-7b. RRTS showed cytotoxic effects on ovarian cancer cells through inducing miR-let-7b expression and decreasing COL3A1 expression. In addition, RRTS sensitized ovarian cancer to Taxol both in vitro and in vivo. In conclusion, the present results revealed synergistic cytotoxicity of RRTS and Taxol on against ovarian cancer cells via upregulating expression of miR-let-7b. Combination of Taxol and RRTS may be a novel treatment strategy for patients with TR ovarian cancer.

Combination of ruthenium (II) polypyridyl complex Δ-Ru1 and Taxol enhances the anti-cancer effect on Taxol-resistant cancer cells through Caspase-1/GSDMD-mediated pyroptosis

Taxol is the first-line drug for cancer treatment. However, tumor resistance to Taxol is still a significant challenge in clinical practice. Here, we studied the synergistic effect of a ruthenium (II) polypyridyl complex, Δ-[Ru(bpy)2(HPIP)](ClO4)2(Δ-Ru1, where bpy = 2,2′-bipyridine, HPIP = 2-(2-hydroxyphenyl) imidazo[4,5-f] [1, 10] phenanthroline) combined with Taxol (Δ-Ru1 & Taxol) on Taxol resistant cervical cancer HeLa cell line (HeLa/Taxol). The results of the Chou-Talalay and Synergyfinder analytical test show that the Δ-Ru1 & Taxol combination has a synergistic effect in HeLa/Taxol cells. Especially, vesicles structures were observed on the membranes of HeLa/Taxol cells treated with Δ-Ru1 & Taxol, accompanied by cell swelling, which characterizes pyroptosis. Furthermore, the release of Interleukin-1β (IL-1β) and Lactate Dehydrogenase (LDH) were increased. At the same time, the activation and cleavage of Caspase-1 and Gasdermin D (GSDMD), the key molecules of the pyroptosis pathway, were detected. In addition, the Δ-Ru1 & Taxol combination had a synergistic anti-tumor effect in the mice model and could effectively inhibit tumor growth and significantly reduce the side effects on the lungs and the neuroethology of Taxol. Taken together, the Δ-Ru1 & Taxol combination can induce cell death through Caspase-1/GSDMD-mediated pyroptosis to enhance the therapeutic effect on HeLa/Taxol cells. This study provides a novel idea for the combined application of ruthenium complexes and other drugs, which may be utilized to overcome cancer drug resistance.

Cytotoxicity of Taxol in Combination with Vincristine and Vinblastine Against A375 Cell Line

Background: Annually, various types of cancer cause thousands of deaths globally, and identifying an appropriate therapeutic option for these disorders is of crucial importance. Side effects of anticancer drugs can be reduced through the promising strategy of combination therapy. Objectives: The present paper has investigated the in vitro cytotoxicity of Taxol, carboplatin, vinblastine, and vincristine alone and in combination against human malignant melanoma A375 cells and non-cancerous fibroblast HU2 cells to examine the possible side effects of the drugs. Methods: The cells were subjected to the examined compounds for 48 h, and the MTT test was conducted to evaluate the cytotoxicity. Results: The results indicated that the most significant effect was related to 120 μg/mL vincristine and 7.5 μg/mL Taxol+ vincristine treatments, with the survival amounts of 24 ± 0.6 and 28 ± 0%, respectively. In addition, the best 50% inhibitory effect was found to be related to Taxol + vincristine, vinblastine, and Taxol+ vinblastine treatments at the concentrations of 0.04, 2.2, and 3.4 μg/mL, respectively. Conclusions: According to the findings of in vitro toxicity, the evaluated complexes are not cytotoxic against human fibroblast HU2 cells. Also, the most significant effect on A375 cells was associated with vincristine treatment. No synergistic reaction was recorded among the different combinations of drugs based on the calculated CI values.

MicroRNA-424-5p enhances chemosensitivity of breast cancer cells to Taxol and regulates cell cycle, apoptosis, and proliferation.

Combination therapy has been considered as a potential method to overcome the BC chemoresistance. MicroRNAs (miRs) have been suggested as a therapeutic factor in the combination therapy of BC. This project aimed at examining the possible activity and molecular function of miR-424-5p and Taxol combination in the human BC cell line. MDA-MB-231 cells were treated with miR-424-5p mimics and Taxol, in a combined manner or separately. We used the MTT test for assessing the cell proliferation. In addition, flow-cytometry was used for evaluating apoptosis and cell-cycle. Expression levels of underlying molecular factors of miR-424-5p were assessed using western-blotting and qRT-PCR. The obtained results demonstrated that miR-424-5p repressed BC cell proliferation and sensitized these cells to Taxol treatment through the induction of apoptosis. Further investigations showed that miR-424-5p might increase BC chemosensitivity through the regulation of apoptosis-related factors including P53, Caspase-3, Bcl-2, and Bax as well as the proliferation-related gene c-Myc. Moreover, miR-424-5p restoration in combination with Taxol treatment decreased the colony formation by regulating Oct-4 and led to G2 arrest via modulating Cdk-2 expression. Western-blotting demonstrated that miR-424-5p may perform its anti-chemoresistance role by regulating the PD-L1 expression and controlling PTEN/PI3K/AKT/mTOR. Overall, the upregulation of miR-424-5p was indicated to upregulate the sensitivity of BC cells to treatment with Taxol. MiR-424-5p might regulate the chemosensitivity of the BC cell line by modulating PD-L1 and controlling the PTEN/mTOR axis. Therefore, the combination of miR-424-5p with Taxol would represent a novel procedure to treat against BC.

Paclitaxel skin delivery by micelles-embedded Carbopol 940 hydrogel for local therapy of melanoma.

Local application of anticancer drugs provides a potential mode of chemotherapy for cutaneous melanoma with high compliance. However, the efficiency of drug delivery is highly limited by the physiological barrier from the skin to the tumor, which can not achieve the desired therapeutic effect. In the study, we designed ibuprofen-modified methoxy poly (ethylene glycol)-poly (ethylene imine) polymer to prepare paclitaxel-loaded micelles (PTX-M) and Carbopol 940 hydrogel containing PTX-M (PTX-Gel) to improve skin paclitaxel delivery for the local melanoma treatment. The PTX-M performed well both in the skin penetration and retention study. FT-IR analysis showed that PTX-M or PTX-Gel mainly changed the spatial structure of skin lipid and keratin, thus increasing the fluidity of lipid molecules in the stratum corneum, and the polymer was positively charged to enhance the skin permeation and deposition. Moreover, the positive charge also promoted the cellular uptake of PTX-M in B16 melanoma, resulting in better in vitro cytotoxicity of PTX-M to B16 cells Taxol®. As for in vivo against B16 cells solid tumor test, the Taxol® plus PTX-M/Gel group showed preferable anticancer activity than Taxol® alone.

Plasticity in Ovarian Cancer: The Molecular Underpinnings and Phenotypic Heterogeneity

Cellular plasticity, by large, is the ability through which cells morph into new phenotypic identity by trading-off with the previous one. This phenomenon has been observed in the normal and tumor cells in a very similar fashion. Occurrence of cellular plasticity, in malignancies like epithelial ovarian carcinoma (EOC) are well known but highly debated in terms of origin of the tumor for the inherent heterogeneity across subtypes. EOC has been termed as a clinically challenging malady for its subversive nature against chemotherapy. The management of ovarian cancer is mostly hindered by relapse with recalcitrance towards primary chemotherapy regimen e.g. platinum–taxol combination. Also, late detection preceded by peritoneal metastasis poses another challenge to the treatment. Underlying both these aspects of the disease, tumor heterogeneity turns out as the most critical factor. In the light of heterogeneity that can be across patients (inter-tumoral) and/or within a tumor (intra-tumoral), ovarian carcinoma is a multifactorial ailment. The governing factors behind this heterogeneity are—diverse genetic landscape among subtypes of EOC; the presence of cancer stem cell (CSC) niche and inherent plasticity of the cancer cells themselves. Apart from the well-studied mechanisms of plasticity, there are several emerging molecular players like lncRNAs, Hippo pathway and also phenomena like dedifferentiation of non-CSC neoplastic cells ,and transdifferentiation of CSCs. Here, we present an overview of the current knowledge on the evolution of EOC through cellular plasticity with emphasis on the three major aspects namely, subtype-specific genetic diversity; ovarian CSC and cancer cell duality between epithelial and mesenchymal lineages.

3,5,4′-Trimethoxy-trans-stilbene loaded microemulsion for cutaneous melanoma therapy by transdermal drug delivery

For therapy of skin cancer, transdermal administration has been a potential way to enhance chemotherapy. However, the drug delivery efficacy remained unsatisfactory because of the physiological barriers from the skin to the tumor, which hindered the effect of 3,5,4'-trimethoxy-trans-stilbene (BTM), a drug that has toxicity to cancer. Herein, we prepared an oil-in-water (O/W) microemulsion to load BTM (BTM-ME) for transdermal therapy of melanoma. BTM-ME was characterized by size, zeta potential, and polymer disperse index (PDI). B16F10 melanoma cell line was used for cell experiments and animal models. And cell uptake, viability assay, and flow cytometry were to test the cell internalization and the ability of BTM-ME to induce cancer cell apoptosis. Skin penetration testing was to detect its penetration efficiency to the skin. And tumor-bearing mice were used to prove the improvement of anti-cancer efficacy of BTM-ME with the combination of Taxol. BTM was successfully loaded in O/W microemulsion, with a drug loading capacity of 24.82mg/mL. BTM-ME can penetrate the skin and increase the retention of BTM in the epidermis. And the combination of Taxol and BTM-ME effectively suppressed tumor growth and has lower toxicity to normal organs. BTM-ME provides adjuvant therapy to cutaneous melanoma and the combination of Taxol and BTM-ME has the clinical potential for skin cancer therapy. Graphical abstract.

MicroRNA‐193a and taxol combination: A new strategy for treatment of colorectal cancer

Micro RNAs (miRNAs) show a considerable promise as a therapeutic agent for combination therapy of colorectal cancer (CRC). Given that, the current study was purposed to explore the potential therapeutic role and underlying mechanism of miR-193a as a promising tumor suppressor in human CRC cell lines in combination with Taxol. Therefore, HT-29 cells with the lowest expression levels of miR-193a were treated with miR-193a mimics and Taxol, separately or in combination. Functional analyses showed that the combination therapy inhibited migration and colony formation of HT-29 cells and arrested the cell cycle at the G1 phase. Moreover, treatment with Taxol reduced cell survival with an increase in mRNA expression of metastasis-related genes caspase-3 and caspase-9, whereas miR-193a transfection alone didn't significantlyinfluence cell viability and apoptosis induction. Quantitative reverse transcription polymerase chain reaction results also revealed that miR-193a replacement decreased the expression levels of c-Myc, MMP-9, vimentin, and ROCK in treatment groups compared to the controls. Therefore, it could be concluded miR-193a inactivates cell migration via suppression of metastasis pathways in CRC and through downregulation of c-Myc, acts as a negative regulator of cell cycle and growth. Then, our findings imply that miR-193a replacement combined with Taxol chemotherapy could be considered as a new potential therapeutic approach for improvement of CRC treatment.

MiR-1207-5p regulates the sensitivity of triple-negative breast cancer cells to Taxol treatment via the suppression of LZTS1 expression.

Taxol-based chemotherapy is a conventional therapeutic approach for the treatment of triple-negative breast cancer (TNBC). However, the insensitivity of TNBC cells to Taxol greatly limits the anticancer effect of the drug and leads to patient mortality. The present study first evaluated the expression levels of microRNA (miR)-1207-5p in human normal breast epithelial MCF-10A cells and TNBC cell lines (MDA-MB-231, MDA-MB-436 and MDA-MB-453). The results revealed that the highest miR-1207-5p level was in MDA-MB-231, which suggested an oncogenic role of miR-1207-5p in TNBC. Therefore, MDA-MB-231 served as the present study's research model in subsequent experiments. The mRNAs that functioned as tumor suppressor factors for miR-1207-5p were then determined. Leucine zipper tumor suppressor gene 1 (LZTS1), which was predicted by TargetScan 6.2 and was supported by the results of a dual luciferase assay, was identified as a target of miR-1207-5p. AntagomiR-1207-5p increased LZTS1 mRNA and protein expressions, enhanced cell growth arrest and cell apoptosis induced by Taxol in MDA-MB-231 cells. Additionally, it was observed that, when compared with Taxol treatment, the combination of Taxol and antagomiR-1207-5p induced a sharp decrease in B-cell lymphoma 2 (Bcl-2) and phosphorylated-protein kinase B expression accompanied by an increase in the Bcl-2-associated X protein expression. Finally, miR-1207-5p expression was significantly increased, while LZTS1 expression was significantly decreased, in TNBC tissues when compared with normal adjacent tissues, and there was a negative correlation between miR-1207-5p and LZTS1 expression. In addition, there was a notable elevation in the expression of miR-1207-5p and a reduction in the expression of LZTS1 in the Taxol non-responsive TNBC tissues when compared with the Taxol-responsive TNBC tissues. The results of the present study suggested that miR-1207-5p may be a promising predictor of sensitivity towards Taxol in TNBC.

Anti-cancer effects of F16: A novel vascular endothelial growth factor receptor-specific inhibitor.

Vascular endothelial growth factor receptor-2 is a dynamic target for therapeutic intervention in various types of cancers. This study was aimed to explore the anti-angiogenic activity of a novel vascular endothelial growth factor receptor-specific inhibitor named F16 in both in vitro and in vivo experimental models. This compound effectively reduced cell proliferation, tube formation, and migration of human umbilical vein endothelial cells in a concentration-dependent manner by directly inhibiting vascular endothelial growth factor binding and subsequent vascular endothelial growth factor receptor-2 phosphorylation. The F16 was also able to inhibit the phosphoinositide 3-kinase/protein kinase B-mediated survival and migration pathways in cancer in addition to inhibiting the focal adhesion kinase and mitogen-activated protein kinases-mediated signaling in GI-101A cancer cells. The chorioallantoic membrane assay followed by tumor growth inhibition measurements with GI-101A breast cancer xenograft implanted athymic nude mice confirmed the in vivo tumor reductive effects of F16. It was interesting to observe a decrease in tumor burden after F16 treatment which correlated very well with the decrease in the plasma levels of mucin-1 (MUC-1). Our studies so far have confirmed that F16 is a specific inhibitor of angiogenesis in both in vitro and in vivo models. The F16 also works very efficiently with Taxol in combination by limiting the tumor growth that is better than the monotherapy with any one of the drugs that were tested individually. Thus, F16 offers a promising anti-proliferative and anti-angiogenic effects with better specificity than some of the existing multi-kinase inhibitors.

Protective role of tocopherol and ascorbic acid in taxol-treated human erythrocytes in vitro

Taxol is a well-known anticancer agent. It is used for the treatment of several kinds of cancer, including breast cancer, lung cancer and ovarian cancer. In spite of being a good chemotherapeutic agent, taxol has several side effects. Drug-induced haemolytic anaemia is one of the most common side effects of taxol. This study investigated the haemolytic effect of taxol on normal erythrocytes and the protective effect of natural antioxidants ascorbic acid and tocopherol in the presence of taxol. We evaluated the osmotic fragility and the activity of enzymes superoxide dismutase and catalase of erythrocytes in the presence of taxol alone and taxol in combination with tocopherol and ascorbic acid. Taxol-induced haematological perturbation significantly caused haemolysis and reduced the activities of superoxide dismutase and catalase in erythrocytes. The antioxidants tocopherol and ascorbic acid demonstrated a protective effect when added to taxol. The combination of tocopherol with taxol significantly protected the osmotic lysis of erythrocytes and increased the activities of superoxide dismutase but had less effect on catalase. Ascorbic acid showed significant protection of erythrocytes from osmotic lysis but didn’t show any significant effect on superoxide and catalase. The results suggest that both antioxidants, especially tocopherol, could exhibit a protective effect against taxol-induced haematological toxicity.

Silencing Op18/stathmin by RNA Interference Promotes the Sensitivity of Nasopharyngeal Carcinoma Cells to Taxol and High-Grade Differentiation of Xenografted Tumours in Nude Mice.

Nasopharyngeal carcinoma (NPC) is a refractory tumour, and chemotherapy is one of the primary treatment modalities. Oncoprotein 18 (Op18)/stathmin is a conserved small cytosolic phosphoprotein and highly expressed in tumours, which plays a vital role in maintaining the malignant phenotype of tumours. Taxol is a clinically widely used chemotherapeutic agent for a broad range of taxol-resistant tumours. This study showed that Op18/stathmin silencing by RNA interference (RNAi) combined taxol cooperatively improved cellular apoptosis in CNE1 cells mainly via initiating endogenous death receptor pathway, impaired the capabilities of cellular proliferation and cellular migration and down-regulated the half maximal inhibitory concentration (IC50 ) of taxol, meanwhile decreased the expression of the upstream extracellular regulated kinase 1 (ERK1) in vitro. Evidence also showed that taxol cytotoxicity was markedly augmented for Op18/stathmin RNAi in other NPC cells. In vivo animal experiments have demonstrated that early combination of Op18/stathmin silencing and taxol evidently inhibited tumourigenicity of CNE1 cells and growth of xenografted tumours in nude mice. Remarkably, silencing Op18/stathmin by RNAi still promoted transformation of late-stage CNE1 cells in NPC-xenografted tumours from moderately to highly differentiated and inhibited the pleiotropic cytokine interleukin-10 (IL-10) autocrine by transplanted tumours. These findings suggest that silencing Op18/stathmin by RNAi promotes chemosensitization of NPC to taxol and reverses malignant phenotypes of NPC, which provides a new clue for treating drug-resistant tumours.

SMIFH2-mediated mDia formin functional inhibition potentiates chemotherapeutic targeting of human ovarian cancer spheroids.

Due to a lack of effective screening or prevention protocol for epithelial ovarian cancer (EOC), there is a critical unmet need to develop therapeutic interventions for EOC treatment. EOC metastasis is unique. Initial dissemination is not primarily hematogenous, yet is facilitated through shedding of primary tumor cells into the peritoneal fluid and accumulating ascites. Increasingly, isolated patient spheroids point to a clinical role for spheroids in EOC metastasis. EOC spheroids are highly invasive structures that disseminate upon peritoneal mesothelium, and visceral tissues including liver and omentum. Selection for this subset of chemoresistant EOC cells could influence disease progression and/or recurrence. Thus, targeting spheroid integrity/structure may improve the chemotherapeutic responsiveness of EOC. We discovered a critical role for mammalian Diaphanous (mDia)-related formin-2 in maintaining EOC spheroid structure. Both mDia2 and the related mDia1 regulate F-actin networks critical to maintain cell-cell contacts and the integrity of multi-cellular epithelial sheets. We investigated if mDia2 functional inhibition via a small molecule inhibitor SMIFH2 combined with chemotherapeutics, such as taxol and cisplatin, inhibits the viability of EOC monolayers and clinically relevant spheroids. SMIFH2-mediated mDia formin inhibition significantly reduced both ES2 and Skov3 EOC monolayer viability while spheroid viability was minimally impacted only at the highest concentrations. Combining either cisplatin or taxol with SMIFH2 did not significantly enhance the effects of either drug alone in ES2 monolayers, while Skov3 monolayers treated with taxol or cisplatin and SMIFH2 showed significant additive inhibition of viability. ES2 spheroids were highly responsive with clear additive anti-viability effects with dual taxol or cisplatin when combined with SMIFH2 treatments. While combined taxol with SMIFH2 in spheroids showed an additive effect relative to single treatments, Skov3 spheroids showed no additive effects from combined cisplatin and SMIFH2 treatments. Our data indicate that mDia formin inhibition combined with taxol to drive enhanced and/or additive anti-viability effects targeting 3D EOC structures, including ES2 and Skov3 spheroids. Combined mDia formin inhibition with cisplatin may be most effective in EOC spheroids where cisplatin sensitivity is retained at moderate levels, such as ES2 cells.

Abstract B172: RP10107, a novel and potent glutaminase inhibitor, potentiates taxol activity in breast cancer cell lines

Abstract Background: Breast cancer is the leading cause of cancer-related death among women worldwide. While early detection techniques, adjuvant therapy, and hormone replacement therapy, have led to a substantial decrease in mortality rates, breast cancer, especially triple negative breast cancer (TNBC) remains an important unmet clinical challenge. Although, Taxol, a mitotic inhibitor, is widely used in conjunction with other chemotherapeutic drugs for both early and late stage breast cancer, it is fraught with adverse effects. With cancer cell metabolism emerging as a critical regulator of tumor progression, combining Taxol with an inhibitor of the metabolic machinery represents a potential therapeutic strategy to prevent breast cancer progression. RP10107 is a novel, potent, and selective glutaminase (GLS-1) inhibitor that demonstrated high potency against mouse (IC50 = 21.2 nM), rat (IC50 = 18.2 nM) and human (IC50 = 26.4 nM) enzymes with selectivity over GLS-2 (>380-fold). The objective of this study was to evaluate the effect of a combination of Taxol and RP10107 in breast cancer cell lines. Methods: Half-maximal growth inhibition of MDA-MB-231 (TNBC), MCF-7 (ER+, PR+), and ZR 75.1 (ER+) cells was assessed using the colorimetric MTT reagent following incubation with Taxol or in combination with 30 nM RP10107 for 72 h. Additionally, synergism between Taxol and RP10107 was determined using different concentrations of the compounds in a 5 × 5 grid. Synergism, additivity, or antagonism was calculated based on the BLISS score. Apoptosis was determined by Annexin V/7AAD staining using a MUSE® Annexin V and dead cell assay kit (Millipore). Results: Taxol inhibited growth of MDA-MB-231, MCF-7, and ZR 75.1 cells with GI50 of 48.9, 2.9, and 1.6 nM, respectively. Although the shift in GI50 upon addition of 30 nM RP10107 in MCF-7 and ZR 75.1 was modest, a >480-fold reduction was observed in the TNBC cell line, MDA-MB-231 (GI50 = 0.9 nM). Similarly, while synergism (BLISS score >10) between Taxol and RP10107 was noticed in all the cell lines tested, effect was most pronounced in MDA-MB-231 cells with >70% growth inhibition seen upon combining of 3 nM Taxol with 10 nM RP10107. Additionally, incubation with the combination (1 nM Taxol + 1 nM RP10107) for 72 h increased the percent of apoptotic cells in MDA-MB-231 cells (35%) compared to the individual agents. Conclusions: Addition of RP10107, a potent and selective GLS-1 inhibitor, potentiated Taxol activity in breast cancer cells with remarkable synergy evident in the TNBC cell line, MDA-MB-231. Findings provide a rationale for use of the combination in future clinical trials involving hard-to-treat TNBC patients thereby providing a safer and much effective option compared to currently available therapy. Citation Format: Kumar V. Penmetsa, Satyanarayana Eleswarapu, Saketh Sriram Dinavahi, Srikant Viswanadha, Swaroop Vakkalanka. RP10107, a novel and potent glutaminase inhibitor, potentiates taxol activity in breast cancer cell lines. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B172.

Abstract A2-27: Effects of C-Phycocyanin in combination with anticancer drugs in lung cancer implanted mice

Abstract The C-Phycocyanin (C-PC) is a pigmented phycobiliprotein that is produced by the blue-green algae (cyanobacterium) named Spirulina platensis and Limnothrix sp. For the first time we have tested the anticancer properties of C-PC from the cyanobacterial isolate Limnothrix sp., that is found in Florida's Everglades, using cancer cells and xenograft tumor model. Our preliminary studies confirm that C-PC from Limnothrix have antiproliferative activity against LNCaP prostate cancer cells. However, as expected the required concentration of C-PC for anticancer activity is well above the usual doses of anticancer drugs normally used. Therefore, we speculated that C-PC could potentiate the anticancer effects of certain therapeutic agents when used in combination treatment. Initially the cytotoxic effects of C-PC and Topotecan (TPT) were confirmed using cell viability assays in A-549 lung cancer cells. Also, it was determined that C-PC treatment could significantly down regulate the levels of Bcl-2, an anti-apoptotic protein, to induce apoptosis. Furthermore, our in vivo experiments confirmed the efficacy of C-PC in potentiating the anticancer effects of Taxol, Topotecan and Cisplatin in athymic nude mice that were sub-cutaneously implanted with the xenograft tumors established from A549 lung cancer cells. During the treatment period the experimental mice had free access to C-PC dissolved in drinking water at a dose of 100 mg/Kg body weight. All the other anticancer drugs were given as intraperitoneal (i.p.) injections at a dose of 1.0 mg/kg body weight twice a week for a period of 60 days. Tumor growth was assessed once in every two weeks using caliper measurements. At the end of the treatment period the level of lung tumor biomarker CYFRA 21-1 in serum was analyzed. As a result of the treatment, the tumor growth was found to be 54%, 46% and 33% less in Taxol; TPT and Cisplatin treated groups compared to the control group. Interestingly C-PC + Taxol combination showed 75% inhibition while C-PC + TPT showed 51% and C-PC + Cisplatin showed 40% inhibition of tumor growth. Thus, the mice treated with the C-PC + Taxol combination showed an additional 21% tumor growth inhibition when compared to group treated with Taxol alone. Furthermore, the decreased level of CYFRA 21-1in serum showed a good correlation with the inhibition of tumor growth in C-PC + Taxol treated animals. Results from our study confirm that C-PC from Limnothrix sp., can significantly enhance the anticancer activity of Taxol against the A549 lung tumor in athymic nude mice possibly by decreasing the levels of Bcl-2. (This project was supported by the PFRDG grant of NSU and grants from the James & Esther King Biomedical Research Program of the State of Florida and the Royal Dames of Cancer Research Inc., Ft. Lauderdale, Florida). Citation Format: Sivanesan Dhandayuthapani, Miroslav Gantar, Appu Rathinavelu. Effects of C-Phycocyanin in combination with anticancer drugs in lung cancer implanted mice. [abstract]. In: Proceedings of the AACR Special Conference on Translation of the Cancer Genome; Feb 7-9, 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 1):Abstract nr A2-27.

Abstract 5318: Effect of C-phycocyanin on the anticancer properties of taxol and topotecan in lung cancer implanted athymic nude mice

Abstract The biodiversity of marine environment and the associated chemical multiplicity offers unlimited resource for discovering new antitumor agents. For the first time we have tested the anticancer properties of C-phycocyanin (C-PC) isolated from a unique cyanobacterial strain named Limnothrix sp., which is found in Florida's Everglades. Our preliminary studies originally confirmed antiproliferative activity of C-PC against LNCaP prostate cancer cells and subsequently against A549 lung cancer cells also. Therefore, we speculated that C-PC could potentiate the anticancer effects of certain therapeutic agents when used in combination treatments. For this purpose the cytotoxic effects of C-PC and topotecan were confirmed using cell viability assays in A549 lung cancer cells. Subsequently, our in vivo experiments confirmed the efficacy of C-PC in potentiating the anticancer effects of taxol and topotecan in athymic nude mice that were sub-cutaneously implanted with the xenograft tumors established from A549 lung cancer cells. During the treatment period the experimental mice had free access to C-PC that was dissolved in drinking water at a dose of 100 mg/kg body weight. The anticancer drugs were given as intraperitoneal injections at a dose of 1.0 mg/kg body weight twice a week for a period of 60 days. The tumor growth was assessed once in every two weeks using caliper measurements. At the end of the treatment period the levels of lung tumor biomarkers CYFRA 21-1 (Cytokeratin 19 fragments) and CEA (Carcino Embryonic Antigen) in serum were analyzed. As a result of the treatment, the tumor growth was found to be 54% and 46% less in taxol and topotecan treated groups compared to the control group. Interestingly C-PC + taxol combination showed 75% inhibition of tumor growth. Thus, the mice treated with the C-PC + taxol combination showed an additional 21% tumor growth inhibition when compared to the group treated with taxol alone. Furthermore, the levels of the tumor biomarkers CYFRA 21-1 and CEA in serum were significantly reduced by the treatment showing a good correlation with the inhibition of tumor growth in C-PC + taxol treated animals. The C-PC + taxol combination treated animals showed 91% decrease while C-PC alone was able to reduce the levels of CYFRA 21-1 by 85%. Similarly, the CEA levels were reduced by 97% following the C-PC + taxol combination treatment. It was further determined that C-PC treatment could significantly down regulate the levels of anti-apoptotic protein such as Bcl-2 to trigger apoptosis in lung cancer cells. Thus, results from our study confirm that C-PC from Limnothrix sp., can significantly enhance the anticancer activity of taxol against the A549 lung tumor in athymic nude mice possibly by decreasing the levels of Bcl-2. (Project was supported by the PFRDG grant of NSU, James & Esther King Biomedical Research Program of the State of Florida and The Royal Dames of Cancer Research Inc., Ft. Lauderdale, Florida). Citation Format: Sivanesan Dhandayuthapani, Miroslav Gantar, Thanigaivelan Kanagasabai, Manasa Subbarao, Appu Rathinavelu. Effect of C-phycocyanin on the anticancer properties of taxol and topotecan in lung cancer implanted athymic nude mice. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5318. doi:10.1158/1538-7445.AM2015-5318

Role of Immune Modulators in Drug‐drug Interaction between Irinotecan and Taxol

Drug-drug interaction (DDIs) is one of the major contributors to adverse drug reaction. Alterations of drug metabolizing enzymes (DMEs) by a drug can lead to changes in metabolism of other co-administrated drugs, which can in turn cause DDIs. Inflammation-mediated impairment of DMEs has been known to occur, however, the molecular mechanism is still not fully known. One of the primary mediators of inflammatory responses in the body are the Toll-like receptors (TLRs) and represents the first line of host defense against pathogens. So far 13 TLRs have been identified in mammals. We have previously shown activation of TLR2 and TLR4 leads to down-regulation of expression and activity of DMEs during inflammation, thus they may have a role in DDIs. In Phase I study of irinotecan and taxol combination therapy for advanced non-small cell lung cancer, preceding taxol treatment increased the levels of both irinotecan and its active metabolite, SN-38. Interestingly, we found that taxol induced the enzymes; Ugt1a1and Cyp 3a11 involved in irinotecan metabolism in TLR4 dependent manner. Therefore, we hypothesize that taxol will alter pharmacokinetics of irinotecan and SN-38 by regulating expression of Ugt1a1 & Cyp3a11 in TLR4-dependent manner. Taxol significantly induced expression of Cyp3a11 (~600fold) and Ugt1a1 (~4 fold) in TLR4WT hepatocytes whereas the induction was attenuated in TLR4 mutant. This TLR4 dependent induction of Ugt1a1 & Cyp3a11 by taxol resulted in higher levels of SN-38G by ~2 fold at 24h when treated along with irinotecan at 50 & 20 µM but SN38 only at 50 µM. Our result indicates the role of TLR4 in DDI between taxol and Irinotecan and proposes the need for dose adjustment in patients with TLR4 polymorphism.

Combination of Taxol® and dichloroacetate results in synergistically inhibitory effects on Taxol-resistant oral cancer cells under hypoxia

Cancer cells preferentially catalyze glucose through the glycolytic pathway in the presence of adequate oxygen. This phenomenon is known as the Warburg effect. As is the case with numerous cancer therapeutic agents, resistance remains a significant problem when using Taxol® to treat malignancies. The present study reported that expression of pyruvate dehydrogenase kinase 1 (PDK1) was induced by Taxol treatment at low toxic concentrations in oral cancer cells. In addition, Taxol‑resistant cells exhibited upregulated PDK1 protein and mRNA expression. Elevated PDK1 levels contribute to Taxol resistance under hypoxic conditions. Inhibition of PDK1 expression was observed when oral cancer cells were treated with the PDK1 inhibitor dichloroacetate (DCA). The combination of Taxol with DCA showed synergistic inhibitory effects on Taxol‑resistant cells under hypoxic conditions; these effects were not observed in Taxol‑sensitive oral cancer cells under normoxic conditions. The present study provides a novel mechanism for overcoming Taxol resistance in oral cancer cells, and will contribute towards the development of clinical therapeutics for cancer patients.