Novel mechanisms and approaches to overcome multidrug resistance in the treatment of ovarian cancer

CRISPR/Cas9-mediated silencing of CD44: unveiling the role of hyaluronic acid-mediated interactions in cancer drug resistance

A comprehensive overview of CD44 (CD44 Molecule (Indian Blood Group)), a cell surface glycoprotein, and its interaction with hyaluronic acid (HA) in drug resistance mechanisms across various types of cancer is provided, where CRISPR/Cas9 gene editing was utilized to silence CD44 expression and examine its impact on cancer cell behavior, migration, invasion, proliferation, and drug sensitivity. The significance of the HA-CD44 axis in tumor microenvironment (TME) delivery and its implications in specific cancer types, the influence of CD44 variants and the KHDRBS3 (KH RNA Binding Domain Containing, Signal Transduction Associated 3) gene on cancer progression and drug resistance, and the potential of targeting HA-mediated pathways using CRISPR/Cas9 gene editing technology to overcome drug resistance in cancer were also highlighted.

Efficacy and safety of Trastuzumab Emtansine in treating human epidermal growth factor receptor 2-positive metastatic breast cancer in Chinese population: a real-world multicenter study

Background

Trastuzumab emtansine (T-DM1) has been approved worldwide for treating metastatic breast cancer (mBC) in patients who have received first-line therapy, shown disease progression, and are human epidermal growth factor receptor 2 (HER2)-positive. T-DM1 received approval in China to treat early-stage breast cancer (BC) in 2020 and for mBC in 2021. In March 2023, T-DM1 was included in medical insurance coverage, significantly expanding the eligible population.

Materials and methods

This post-marketing observational study aimed to assess the safety and effectiveness of T-DM1 in real-world clinical practice in China. This study enrolled 31 individuals with HER2-positive early-stage BC and 70 individuals with HER2-positive advanced BC from 8 study centers in Shandong Province, China. The T-DM1 dosage was 3.6 mg/kg injected intravenously every 3 weeks until the disease advanced or the drug toxicity became uncontrollable, whichever occurred earlier. Additionally, efficacy and safety information on T-DM1 were collected.

Results

During the 7-month follow-up period, no recurrence or metastases were observed in patients who had early-stage BC. The disease control rate was 31.43% (22/70) in patients with advanced BC. The most common adverse effect of T-DM1 was thrombocytopenia, with an incidence of 69.31% (70/101), and the probability of Grade ≥ 3 thrombocytopenia was 11.88% (12/101).

Conclusion

This real-world study demonstrated that T-DM1 had good efficacy and was well tolerated by both HER2-positive early-stage BC and mBC patients.

Peroxiredoxin-1 as a molecular chaperone that regulates glutathione S-transferase P1 activity and drives mutidrug resistance in ovarian cancer cells

Ovarian cancer is among the most prevalent gynecological malignancies around the globe. Nonetheless, chemoresistance continues to be one of the greatest obstacles in the treatment of ovarian cancer. Therefore, understanding the mechanisms of chemoresistance and identifying new treatment options for ovarian cancer patients is urgently required. In this study, we found that the mRNA and protein expression levels of PRDX1 were significantly increased in cisplatin resistant A2780/CDDP cells. Cell survival assays revealed that PRDX1 depletion substantially increased ovarian cancer cell sensitivity to cisplatin, docetaxel, and doxorubicin. Additionally, PRDX1 significantly increased GSTP1 activity, resulting in multidrug resistance. Biochemical experiments showed that PRDX1 interacted with GSTP1 through Cysteine 83, which regulated GSTP1 activity as well as chemotherapy resistance in ovarian cancer cells. Our findings indicate that the molecular chaperone activity of PRDX1 is a promising new therapeutic target for ovarian cancer.

Characterization of chemoresistant human non-small cell lung cancer cells by metabolic and lipidomic profiling

INTRODUCTION

Lung cancer is one of the most malignant cancers and the leading cause of cancer-related deaths worldwide, while acquired chemoresistance would represent a major problem in the treatment of non-small cell lung cancer (NSCLC) because of the reduced treatment effect and increased rates of recurrence.

METHODS

To establish the chemoresistant NSCLC cells, doxorubicin was treated to A549 cells over 3 months at gradually increasing concentrations from 0.03 to 0.5 µM. Real-time PCR and Western blotting were employed for investigating mRNA and protein expression of the glutathione peroxidase (GPX) protein family and multidrug resistance protein 1 (MRP1) in A549 and A549/CR cells. We also employed gas chromatography mass-spectrometry and nano electrospray ionization mass-spectrometry coupled with multivariate statistical analysis to characterize the unique metabolic and lipidomic profiles of chemoresistant NSCLC cells in order to identify potential therapeutic targets.

RESULTS

Reactive oxygen species levels were decreased, and mRNA and protein levels of GPX2 and multidrug resistance protein 1 (MRP1) were increased in A549/CR. We identified 87 metabolites and intact lipid species in A549 and A549/CR. Among these metabolites, lactic acid, glutamic acid, glycine, proline, aspartic acid, succinic acid, and ceramide, alongside the PC to PE ratio, and arachidonic acid-containing phospholipids were suggested as characteristic features of chemoresistant NSCLC cells (A549/CR).

CONCLUSIONS

This study reveals characteristic feature differences between drug-resistance NSCLC cells and their parental cells. We suggest potential therapeutic targets in chemoresistant NSCLC. Our results provide new insight into metabolic and lipidomic alterations in chemoresistant NSCLC. This could be used as fundamental information to develop therapeutic strategies for the treatment of chemoresistant NSCLC patients.

Mechanisms of Drug Resistance in Ovarian Cancer and Associated Gene Targets

In the United States, over 100,000 women are diagnosed with a gynecologic malignancy every year, with ovarian cancer being the most lethal. One of the hallmark characteristics of ovarian cancer is the development of resistance to chemotherapeutics. While the exact mechanisms of chemoresistance are poorly understood, it is known that changes at the cellular and molecular level make chemoresistance challenging to treat. Improved therapeutic options are needed to target these changes at the molecular level. Using a precision medicine approach, such as gene therapy, genes can be specifically exploited to resensitize tumors to therapeutics. This review highlights traditional and novel gene targets that can be used to develop new and improved targeted therapies, from drug efflux proteins to ovarian cancer stem cells. The review also addresses the clinical relevance and landscape of the discussed gene targets.

Interaction Analysis of MRP1 with Anticancer Drugs Used in Ovarian Cancer: In Silico Approach

Multidrug resistance (MDR) is one of the major therapeutic challenges that limits the efficacy of chemotherapeutic response resulting in poor prognosis of ovarian cancer (OC). The multidrug resistance protein 1 (MRP1) is a membrane-bound ABC transporter involved in cross resistance to many structurally and functionally diverse classes of anticancer drugs including doxorubicin, taxane, and platinum. In this study, we utilize homology modelling and molecular docking analysis to determine the binding affinity and the potential interaction sites of MRP1 with Carboplatin, Gemcitabine, Doxorubicin, Paclitaxel, and Topotecan. We used AutoDock Vina scores to compare the binding affinities of the anticancer drugs against MRP1. Our results depicted Carboplatin < Gemcitabine < Topotecan < Doxorubicin < Paclitaxel as the order of binding affinities. Paclitaxel has shown the highest binding affinity whereas Carboplatin displayed the lowest affinity to MRP1. Interestingly, our data showed that Carboplatin, Paclitaxel, and Topotecan bind specifically to Asn510 residue in the transmembrane domains 1 of the MRP1. Our results suggest that Carboplatin could be an appropriate therapeutic choice against MRP1 in OC as it couples weakly with Carboplatin. Further, our findings also recommend opting Carboplatin with Gemcitabine as a combinatorial chemotherapeutic approach to overcome MDR phenotype associated with recurrent OC.

Orchidaceae-Derived Anticancer Agents: A Review

Simple Summary

Orchids are commonly used in folk medicine for the treatment of infections and tumors but little is known about the actual chemical composition of these plants and their anticancer properties. In this paper, the most recent literature on orchid-derived bioactive substances with anticancer properties is reviewed. According to the published data, numerous species of orchids contain potential antitumor chemicals. Still, a relatively insignificant number of species of orchids have been tested for their bioactive properties and most of those studies were on Asian taxa. Broader research, ’including American and African species, as well as the correct identification of samples, is essential for evaluating the usefulness of orchids as a plant family with huge anticancer potential.

Abstract

Species of orchids, which belong to the largest family of flowering plants, are commonly used in folk medicine for the treatment of infections and tumors. However, little is known about the actual chemical composition of these plants and their anticancer properties. In this paper, the most recent literature on orchid-derived bioactive substances with anticancer properties is reviewed. For the assessment, previous papers on the anticancer activity of Orchidaceae published since 2015 were considered. The papers were found by exploring electronic databases. According to the available data, many species of orchids contain potential antitumor chemicals. The bioactive substances in a relatively insignificant number of orchids are identified, and most studies are on Asian taxa. Broader research on American and African species and the correct identification of samples included in the experiments are essential for evaluating the usefulness of orchids as a plant family with vast anticancer potential.

Cajanol Sensitizes A2780/Taxol Cells to Paclitaxel by Inhibiting the PI3K/Akt/NF-κB Signaling Pathway

Ovarian cancer is the second most common gynecological malignancy, and one of the most deadly. The bottleneck restricting the treatment of ovarian cancer is its multi-drug resistance to chemotherapy. Cajanol is an isoflavone from pigeon pea (Cajanus cajan) that has been reported to have anti-tumor activity. In this work, we evaluate the effect of cajanol in reversing paclitaxel resistance of the A2780/Taxol ovarian cancer cell line in vitro and in vivo, and we discuss its mechanism of action. We found that 8 μM cajanol significantly restored the sensitivity of A2780/Taxol cells to paclitaxel, and in vivo experiments demonstrated that the combination of 0.5 mM/kg paclitaxel and 2 mM/kg cajanol significantly inhibited the growth of A2780/Taxol metastatic tumors in mice. Flow cytometry, fluorescence quantitative PCR, western blotting and immunohistochemical staining methods were used to study the mechanism of reversing paclitaxel resistance with cajanol. First, we determined that cajanol inhibits paclitaxel efflux in A2780/Taxol cells by down-regulating permeability glycoprotein (P-gp) expression, and further found that cajanol can inhibit P-gp transcription and translation through the PI3K/Akt/NF-κB pathway. The results of this work are expected to provide a new candidate compound for the development of paclitaxel sensitizers.

Ruthenium(II) and Platinum(II) Complexes with Biologically Active Aminoflavone Ligands Exhibit In Vitro Anticancer Activity

Continuing our studies on the mechanisms underlying the cytotoxicity of potential drugs, we have described several aspects of the in vitro anticancer activity of ruthenium(II) and platinum(II) complexes with bioactive, synthetic aminoflavone ligands. We examined the mechanism of proapoptotic activity of cis-dichlorobis(3-imino-2-methoxyflavanone)ruthenium(II), cis-dichlorobis(3-imino-2-ethoxyflavanone)ruthenium(II), and trans-dichlorobis(3-aminoflavone)platinum(II). Cisplatin was used as a reference compound. The cytotoxicity was investigated by MTT assay. The mechanism of proapoptotic activity of the tested compounds was investigated by evaluation of caspase-8 activity, cytometric analysis of annexin-V positive cells, and mitochondrial potential loss measurement. The results showed that ruthenium compounds break partially or completely the cisplatin resistance by activating the caspase 8-dependent apoptosis pathway and loss of mitochondrial membrane potential. Platinum compounds also have a cytostatic effect, but their action requires more exposure time. Potential mechanisms underlying drug resistance in the two pairs of cancer cell lines were investigated: total glutathione content, P-glycoprotein activity, and differences in the activity of DNA repair induced by nucleotide excision. Results showed that cisplatin-resistant cells have elevated glutathione levels relative to sensitive cells. Moreover, they indicated the mechanisms enabling cells to avoid apoptosis caused by DNA damage. Pg-P activity has no effect on the development of cisplatin resistance in the cell lines described.

Organoruthenium Complexes with Benzo-Fused Pyrithiones Overcome Platinum Resistance in Ovarian Cancer Cells

Drug resistance to existing anticancer agents is a growing clinical concern, with many first line treatments showing poor efficacy in treatment plans of some cancers. Resistance to platinum agents, such as cisplatin, is particularly prevalent in the treatment of ovarian cancer, one of the most common cancers amongst women in the developing world. Therefore, there is an urgent need to develop next generation of anticancer agents which can overcome resistance to existing therapies. We report a new series of organoruthenium(II) complexes bearing structurally modified pyrithione ligands with extended aromatic scaffold, which overcome platinum and adriamycin resistance in human ovarian cancer cells. The mechanism of action of such complexes appears to be unique from that of cisplatin, involving G1 cell cycle arrest without generation of cellular ROS, as is typically associated with similar ruthenium complexes. The complexes inhibit the enzyme thioredoxin reductase (TrxR) in a model system and reduce cell motility towards wound healing. Importantly, this work highlights further development in our understanding of the multi-targeting mechanism of action exhibited by transition metal complexes.

α3 integrin-binding peptide-functionalized polymersomes loaded with volasertib for dually-targeted molecular therapy for ovarian cancer

Ovarian cancer (OC) is a high-mortality malignancy in women with a five-year survival rate of 30-40%. There is an urgent need to develop high-efficacy and low toxic treatments for OC. Herein, we report an appealing strategy that combines α₃ integrin targeted polymersomes (A3-Ps) and targeted molecular drug, polo-like kinase 1 (PLK1) inhibitor volasertib (Vol) for dually targeted molecular therapy of OC in vivo. A3-Ps had good Vol loading of 7.7-8.0 wt.% and small size of 25-32 nm, depending on the density of α₃ integrin binding peptide A3. Interestingly, cellular uptake studies using FITC-labeled Vol revealed that A3-Ps with 20% peptide gave 2.3 and 3.3-fold better internalization in SKOV-3 OC cells compared with non-targeted Ps and free Vol, respectively. Accordingly, Vol loaded in A3-Ps showed the best inhibitory activity to SKOV-3 cells with an IC₅₀ of 49 nM, which was 3.5 times lower than free Vol. Importantly, the in vivo experiments demonstrated that A3-Ps-Vol proficiently repressed the growth of SKOV-3 tumors in mice while continuous tumor growth was observed for Ps-Vol and free Vol-treated mice. A3-Ps-Vol besides boosting anti-OC activity also reduced the systemic toxicity of Vol. This dually targeted molecular drug nanoformulation has appeared to be an especially potent and low toxic treatment modality for human ovarian cancers. STATEMENT OF SIGNIFICANCE: Volasertib provides a potential molecular therapy for PLK1-positive advanced OC patients. The initial clinical outcomes, nevertheless, showed a suboptimal efficacy, possibly resulting from its fast clearance, deficient tumor deposition and dose-limiting toxicities. Here, we show for the first time that dually targeted molecular therapy of OC using α₃ integrin-binding peptide-modified polymersomes as a vehicle gives markedly improved potency, better toleration, and depleted adverse effects in SKOV-3 tumor models, greatly outperforming free volasertib. This dually targeted strategy has emerged as an appealing treatment for malignant PLK1-positive ovarian tumors.

Targeting Nrf2 may reverse the drug resistance in ovarian cancer

Background

Acquired resistance to therapeutic drugs has become an important issue in treating ovarian cancer. Studies have shown that the prevalent chemotherapy resistance (cisplatin, paclitaxel etc.) for ovarian cancer occurs partly because of decreased production of reactive oxygen species within the mitochondria of ovarian cancer cells.

Main Body

Nuclear erythroid-related factor-2 (Nrf2) mainly controls the regulation of transcription of genes through the Keap1-Nrf2-ARE signaling pathway and protects cells by fighting oxidative stress and defending against harmful substances. This protective effect is reflected in the promotion of tumor cell growth and their resistance to chemotherapy drugs. Therefore, inhibition of the Nrf2 pathway may reverse drug resistance. In this review, we describe the functions of Nrf2 in drug resistance based on Nrf2-associated signaling pathways determined in previous studies.

Conclusions

Further studies on the relevant mechanisms of Nrf2 may help improve the outcomes of ovarian cancer therapy.

Delphinidin Increases the Sensitivity of Ovarian Cancer Cell Lines to 3-Bromopyruvate

3-Bromopyruvic acid (3-BP) is a promising anticancer compound. Two ovary cancer (OC) cell lines, PEO1 and SKOV3, showed relatively high sensitivity to 3-BP (half maximal inhibitory concentration (IC₅₀) of 18.7 and 40.5 µM, respectively). However, the further sensitization of OC cells to 3-BP would be desirable. Delphinidin (D) has been reported to be cytotoxic for cancer cell lines. We found that D was the most toxic for PEO1 and SKOV3 cells from among several flavonoids tested. The combined action of 3-BP and D was mostly synergistic in PEO1 cells and mostly weakly antagonistic in SKOV3 cells. The viability of MRC-5 fibroblasts was not affected by both compounds at concentrations of up to 100 µM. The combined action of 3-BP and D decreased the level of ATP and of dihydroethidium (DHE)-detectable reactive oxygen species (ROS), cellular mobility and cell staining with phalloidin and Mitotracker Red in both cell lines but increased the 2’,7’-dichlorofluorescein (DCFDA)-detectable ROS level and decreased the mitochondrial membrane potential and mitochondrial mass only in PEO1 cells. The glutathione level was increased by 3-BP+D only in SKOV3 cells. These differences may contribute to the lower sensitivity of SKOV3 cells to 3-BP+D. Our results point to the possibility of sensitization of at least some OC cells to 3-BP by D.

Long non-coding RNA FAM83H-AS1 as an emerging marker for diagnosis, prognosis and therapeutic targeting of cancer

Incidence and mortality rates of cancer continue to increase greatly despite the improved diagnostic and therapeutic methods. Based on GLOBOCAN estimates, the numbers of new cancer cases reported in 2018 were ~18.1 million, while the numbers of cancer mortalities were ~9.6 million. It remains difficult to diagnose most cancer patients at early stages. Although cancer therapy market is rapidly evolving, the effectiveness of therapy is still inadequate. Therefore, exploring new biomarkers for diagnosis, prognosis and treatment is essential for cancer management. Long non-coding RNAs (lncRNAs) are unique regulatory molecules that control several cellular processes and are implicated in diverse human diseases including cancer. LncRNAs could serve as potential biomarkers for cancer patients to aid diagnosis and determine prognosis. In addition, numerous lncRNAs have proved their ability to predict response to cancer treatment. FAM83H antisense RNA 1 (FAM83H-AS1) is among those highly dysregulated lncRNAs in cancer. FAM83H-AS1 was demonstrated to participate in the progression of different malignancies and also shown to play a vital role in diagnosis, prognosis and treatment. Here, we analyse recent studies concerning the oncogenic role and molecular mechanisms of lncRNA FAM83H-AS1 in the following cancer types: bladder, breast, lung, hepatocellular, colorectal, gastric, pancreatic, ovarian, cervical cancer as well as glioma.

Targeting Notch signaling pathway as an effective strategy in overcoming drug resistance in ovarian cancer

Ovarian cancer, as one of the most common types of gynecological malignancies, has an increasing rate of incidence worldwide. Despite huge amounts of recent efforts in designing novel therapeutic strategies for complete removal of tumors and increasing overall survival of patients, chemotherapy is still the preferred therapy for ovarian cancer. However, chemotherapy is also challenged by development of drug resistance. Therefore, elucidating the underlying mechanisms of drug reissuance is an urgent need in ovarian cancer. Numerous studies have shown the implication of the Notch signaling pathway in the development of various human malignancies. Therefore, this study will provide a brief overview of the published evidence in support of Notch targeting in reverting multidrug resistance as a safer and novel approach for the improvement of ovarian cancer treatment.

MDR1 Gene Polymorphisms and Its Association With Expression as a Clinical Relevance in Terms of Response to Chemotherapy and Prognosis in Ovarian Cancer

In spite of the significant advancements in the treatment modalities, 30% of advanced stage ovarian cancer (OC) patients do not respond to the standard chemotherapeutic regimen and most of the responders finally relapse over time due to the escalation of multidrug resistance (MDR) Phenomenon. Our present study evaluated chemotherapeutic sensitivity response among 47 ovarian tumor patients of which we found 37 (78.8%) sensitive and remaining 10 (21.2%) resistant. Among the resistant, seven tumor samples were found to be platinum resistant or refractory to platinum (CB/TX), one to carboplatin, and two to 5FU. Notably, all these resistant cases were observed in the disease recurrence group of patients identified at stage III or IV. The stage III resistant cases revealed heterozygous mutation (C/T) in exon 12 (C1236T) and 26 (C3435T) and increased level of mRNA, whereas homozygous mutation (T/T) was found at stage IV tumor patients. The genotypic difference was found to be significant (p = 0.03) for exon 12, and p = 0.003 for exon 26 mutant genotypes. No significant association between genotypes of different exons with tumor stages and tumor grade was observed (p > 0.05). However, a significant association was observed between the genotype of exon-12 and histopathology of tumor tissue (p = 0.028). Statistically, the chemotherapy response was found to be significantly associated with the tumor stage (p = 0.019). We also observed a significant difference in PFS (P = 0.019) and OS (P = 0.047) between tumor grades 1 and 3. Notably, the highest mRNA expression was observed in resistant tumor sample T-32, where interestingly we found homozygosity TT in all of the exons 12, 21, and 26. Thus, we suggest that exons 12 (C1236T) and exon 26 (C3435T) polymorphism may play a role in inducing drug resistance by altering the expression level of the MDR1 gene. To summarize, we suggest that the expression of MDR1 in OC is influenced by tumor stage and genotype variants as well as by chemotherapeutic drugs. Thus our findings suggest that inter individual variability in platinum based therapy may be anticipated by MDR1 genotypes. Further studies on a large number of samples shall eventually lead to provide beneficial information for the individualized chemotherapy.

Search for ABCB1 Modulators Among 2-Amine-5-Arylideneimidazolones as a New Perspective to Overcome Cancer Multidrug Resistance

Multidrug resistance (MDR) is a severe problem in the treatment of cancer with overexpression of glycoprotein P (Pgp, ABCB1) as a reason for chemotherapy failure. A series of 14 novel 5-arylideneimidazolone derivatives containing the morpholine moiety, with respect to two different topologies (groups A and B), were designed and obtained in a three- or four-step synthesis, involving the Dimroth rearrangement. The new compounds were tested for their inhibition of the ABCB1 efflux pump in both sensitive (parental (PAR)) and ABCB1-overexpressing (MDR) T-lymphoma cancer cells in a rhodamine 123 accumulation assay. Their cytotoxic and antiproliferative effects were investigated by a thiazolyl blue tetrazolium bromide (MTT) assay. For active compounds, an insight into the mechanisms of action using either the luminescent Pgp-Glo™ Assay in vitro or docking studies to human Pgp was performed. The safety profile in vitro was examined. Structure–activity relationship (SAR) analysis was discussed. The most active compounds, representing both 2-substituted- (11) and Dimroth-rearranged 3-substituted (18) imidazolone topologies, displayed 1.38–1.46 fold stronger efflux pump inhibiting effects than reference verapamil and were significantly safer than doxorubicin in cell-based toxicity assays in the HEK-293 cell line. Results of mechanistic studies indicate that active imidazolones are substrates with increasing Pgp ATPase activity, and their dye-efflux inhibition via competitive action on the Pgp verapamil binding site was predicted in silico.

High Expression of RING Finger Protein 126 Predicts Unfavorable Prognosis of Epithelial Ovarian Cancer

Background

Ovarian cancer (OC) is one of the leading causes of cancer-related mortality worldwide. The clinical outcome of EOC remains unsatisfactory with current therapeutic approaches such as surgery and platinum/taxane-based chemotherapy. Therefore, novel prognostic markers and personalized therapies targeting specific molecules are urgently needed. Here, we explored whether RNF126, an E3 ubiquitin ligase, is a potential biomarker for epithelial ovarian cancer (EOC).

Material/Methods

This was a retrospective cohort study of 122 EOC patients. The chi-square test was used to assess correlations between RNF126 level and clinical characteristics of enrolled patients. Univariate and multivariate analyses were performed to monitor the prognosis of enrolled patients. In addition, proliferation and invasion assays were conducted to assess the cellular effects of RNF126 on SKOV3 cell progression.

Results

Immunohistochemistry analysis (IHC) revealed that RNF126 was upregulated in EOC tissues compared to adjacent ovarian tissues. In addition, RNF126 expression was remarkably associated with LN metastasis, pathological differentiation, and FIGO stage. RNF126 protein level was found to be an independent biomarker for predication of prognosis in ovarian cancer patients. Cellular results showed that RNF126 enhanced the proliferation and invasion abilities of SKOV3 cells.

Conclusions

Upregulated protein level of RNF126 in EOC tissues is a biomarker predicting poor outcomes of EOC patients.

The Pyrazolo[3,4-d]pyrimidine Derivative, SCO-201, Reverses Multidrug Resistance Mediated by ABCG2/BCRP

ATP-binding cassette (ABC) transporters, such as breast cancer resistance protein (BCRP), are key players in resistance to multiple anti-cancer drugs, leading to cancer treatment failure and cancer-related death. Currently, there are no clinically approved drugs for reversal of cancer drug resistance caused by ABC transporters. This study investigated if a novel drug candidate, SCO-201, could inhibit BCRP and reverse BCRP-mediated drug resistance. We applied in vitro cell viability assays in SN-38 (7-Ethyl-10-hydroxycamptothecin)-resistant colon cancer cells and in non-cancer cells with ectopic expression of BCRP. SCO-201 reversed resistance to SN-38 (active metabolite of irinotecan) in both model systems. Dye efflux assays, bidirectional transport assays, and ATPase assays demonstrated that SCO-201 inhibits BCRP. In silico interaction analyses supported the ATPase assay data and suggest that SCO-201 competes with SN-38 for the BCRP drug-binding site. To analyze for inhibition of other transporters or cytochrome P450 (CYP) enzymes, we performed enzyme and transporter assays by in vitro drug metabolism and pharmacokinetics studies, which demonstrated that SCO-201 selectively inhibited BCRP and neither inhibited nor induced CYPs. We conclude that SCO-201 is a specific, potent, and potentially non-toxic drug candidate for the reversal of BCRP-mediated resistance in cancer cells.

3-Aryl-4-nitrobenzothiochromans S,S-dioxide: From Calcium-Channel Modulators Properties to Multidrug-Resistance Reverting Activity

Our research groups have been involved for many years in studies aimed at identifying new active organic compounds endowed with pharmacological properties. In this work, we focused our attention on the evaluation of cardiovascular and molecular drug resistance (MDR) reverting activities of some nitrosubstituted sulphur-containing heterocycles. Firstly, we have examined the effects of 4-nitro-3-(4-methylphenyl)-3,6-dihydro-2H-thiopyran S,S-dioxide 5, and have observed no activity. Then we have extended our investigation to the 3-aryl-4-nitrobenzothiochromans S,S-dioxide 6 and 7, and have observed an interesting biological profile. Cardiovascular activities were assessed for all compounds using ex vivo studies, while the MDR reverting effect was evaluated only for selected compounds using tumor cell lines. All compounds were shown to affect cardiovascular parameters. Compound 7i exerted the most effect on negative inotropic activity, while 6d and 6f could be interesting molecules for the development of more active ABCB1 inhibitors. Both 6 and 7 represent structures of large possible biological interest, providing a scaffold for the identification of new ABCB1 inhibitors.

10-Gingerol Inhibits Ovarian Cancer Cell Growth by Inducing G2 Arrest

Purpose: Gingerol homologs found in the rhizomes of ginger plants have the potential to benefit human health, including the prevention and treatment of cancer. This study evaluated the effect of 10-gingerol on ovarian cancer cell (HEY, OVCAR3, and SKOV-3) growth. Methods: Cell growth was measured by MTT assays, flow cytometry was used to assess cell proliferation, cytotoxicity and cell cycle progression, and western blotting was used to measure cyclin protein expression. Results: Ovarian cancer cells that were treated with 10-gingerol experienced a time- and dose-dependent decrease in cell number, which was due to a reduction in cell proliferation rather than a cytotoxic effect. Reduced proliferation of 10-gingerol-treated ovarian cancer cells was associated with an increased percentage of cells in G2 phase of the cell cycle and a corresponding reduction in the percentage of cells in G1. Ovarian cancer cells also showed decreased cyclin A, B1, and D3 expression following exposure to 10-gingerol. Conclusion: These findings revealed that 10-gingerol caused a G2 arrest-associated suppression of ovarian cancer cell growth, which may be exploited in the management of ovarian cancer.

Strategies for Delivery of siRNAs to Ovarian Cancer Cells

The unmet need for novel therapeutic options for ovarian cancer (OC) deserves further investigation. Among the different novel drugs, small interfering RNAs (siRNAs) are particularly attractive because of their specificity of action and efficacy, as documented in many experimental setups. However, the fragility of these molecules in the biological environment necessitates the use of delivery materials able to protect them and possibly target them to the cancer cells. Among the different delivery materials, those based on polymers and lipids are considered very interesting because of their biocompatibility and ability to carry/deliver siRNAs. Despite these features, polymers and lipids need to be engineered to optimize their delivery properties for OC. In this review, we concentrated on the description of the therapeutic potential of siRNAs and polymer-/lipid-based delivery systems for OC. After a brief description of OC and siRNA features, we summarized the strategies employed to minimize siRNA delivery problems, the targeting strategies to OC, and the preclinical models available. Finally, we discussed the most interesting works published in the last three years about polymer-/lipid-based materials for siRNA delivery.

What sustains the multidrug resistance phenotype beyond ABC efflux transporters? Looking beyond the tip of the iceberg

Identification of multidrug (MDR) efflux transporters that belong to the ATP-Binding Cassette (ABC) superfamily, represented an important breakthrough for understanding cancer multidrug resistance (MDR) and its possible overcoming. However, recent data indicate that drug resistant cells have a complex intracellular physiology that involves constant changes in energetic and oxidative-reductive metabolic pathways, as well as in the molecular circuitries connecting mitochondria, endoplasmic reticulum (ER) and lysosomes. The aim of this review is to discuss the key molecular mechanisms of cellular reprogramming that induce and maintain MDR, beyond the presence of MDR efflux transporters. We specifically highlight how cancer cells characterized by high metabolic plasticity - i.e. cells able to shift the energy metabolism between glycolysis and oxidative phosphorylation, to survive both the normoxic and hypoxic conditions, to modify the cytosolic and mitochondrial oxidative-reductive metabolism, are more prone to adapt to exogenous stressors such as anti-cancer drugs and acquire a MDR phenotype. Similarly, we discuss how changes in mitochondria dynamics and mitophagy rates, changes in proteome stability ensuring non-oncogenic proteostatic mechanisms, changes in ubiquitin/proteasome- and autophagy/lysosome-related pathways, promote the cellular survival under stress conditions, along with the acquisition or maintenance of MDR. After dissecting the complex intracellular crosstalk that takes place during the development of MDR, we suggest that mapping the specific adaptation pathways underlying cell survival in response to stress and targeting these pathways with potent pharmacologic agents may be a new approach to enhance therapeutic efficacy against MDR tumors.

Synergistic effect of meta-tetra(hydroxyphenyl)chlorin-based photodynamic therapy followed by cisplatin on malignant Hep-2 cells

Purpose

Tumor drug resistance limits the response to chemotherapy. Interestingly, sequential combination therapy enhances the anticancer efficacy of drugs like cisplatin (CDDP) via synergistic effects. We assayed the synergistic effects of combined photodynamic therapy programmed death receptor-ligand 1 (PDT) and chemotherapy in malignant Hep-2 cells.

Methods

In the cultured Hep-2 cells, meta-tetra(hydroxyphenyl)chlorin (m-THPC) and CDDP were administered separately or in combination. The cellular viability and apoptosis were assessed, accompanied by measurement of the expression of Bax, Bcl-2, ATG-7, and LC3 (LC3-I and LC3-II). Additionally, nuclear chromatin changes, drug retention, and PD-L1 expression were further investigated following different treatments.

Results

The sequential treatment significantly diminished cell viability and induced cell apoptosis, in consistency with the usage of single therapeutic strategies, as reflected by an increase in Bax expression and decrease of Bcl-2 expression. Moreover, ATG-7 and LC3-II/LC3-I ratio were reduced after administration of the sequential treatment. Synergetic effect of nuclear chromatin configuration, negative effects of cellular drug retention, and a decrease in PD-L1 expression were observed following the sequential treatment.

Conclusion

The application of sequential treatment of PDT in combination with chemotherapy offers a promising therapeutic option for cancer treatment, by regulating the PD-L1 expression, autophagy, and non-mitochondrial pathways.

Similar Safety Profile of the Enantiomeric N-Aminoalkyl Derivatives of Trans-2-Aminocyclohexan-1-ol Demonstrating Anticonvulsant Activity

Epilepsy is one of the most common neurological disorder in the world. Many antiepileptic drugs cause multiple adverse effects. Moreover, multidrug resistance is a serious problem in epilepsy treatment. In the present study we evaluated the safety profile of three (1–3) new chiral N-aminoalkyl derivatives of trans-2-aminocyclohexan-1-ol demonstrating anticonvulsant activity. Our aim was also to determine differences between the enantiomeric compounds with respect to their safety profile. The results of the study indicated that compounds 1–3 are non-cytotoxic for astrocytes, although they exhibit cytotoxic activity against human glioblastoma cells. Moreover, 1–3 did not affect the viability of HepG2 cells and did not produce adducts with glutathione. Compounds 1–3 demonstrated no mutagenic activity either in the Salmonella typhimurium or in Vibrio harveyi tests. Additionally, the compounds displayed a strong or moderate antimutagenic effect. Finally, the P-glycoprotein (P-gp) ATPase assay demonstrated that both enantiomers are potent P-gp inhibitors. To sum up, our results indicate that the newly synthesized derivatives may be considered promising candidates for further research on anticonvulsant drug discovery and development. Our study indicated the similar safety profile of the enantiomeric N-aminoalkyl derivatives of trans-2-aminocyclohexan-1-ol, although in the previous studies both enantiomers differ in their biotransformation pathways and pharmacological activity.

MicroRNA-936 targets FGF2 to inhibit epithelial ovarian cancer aggressiveness by deactivating the PI3K/Akt pathway

Purpose

MicroRNA-936 (miR-936) was previously reported to be dysregulated and involved in the development of non-small cell lung cancer and glioma. However, the functional roles of miR-936 in epithelial ovarian cancer (EOC) remain unclear. In this study, we aimed to evaluate miR-936 expression in EOC and investigate its regulatory role in EOC cell behavior.

Methods

The expression of miR-936 in EOC was measured by RT-qPCR. Cell proliferation, apoptosis, migration, and invasion in vitro, as well as tumor growth in vivo, were determined by CCK-8, flow cytometry, migration and invasion assays, and xenograft models in nude mice, respectively. Bioinformatics analysis, luciferase reporter assays, RT-qPCR, and Western blot analysis were performed to investigate the relationship between miR-936 and fibroblast growth factor 2 (FGF2).

Results

miR-936 expression was significantly downregulated in EOC tissues and cell lines. Low miR-936 expression was found to be correlated with the tumor size, FIGO stage, and lymphatic metastasis in EOC patients. Functional experiments indicated that ectopic miR-936 expression suppressed EOC cell proliferation, migration, and invasion; promoted cell apoptosis; and decreased tumor growth in vivo. In addition, the FGF2 gene was verified to be a direct target of miR-936 in EOC cells. FGF2 expression levels were upregulated in EOC tissues and were inversely correlated with miR-936 expression. Furthermore, effects of FGF2 silencing were similar to those of miR-936 overexpression in EOC cells. Recovered FGF2 expression rescued the miR-936-induced inhibitory effects in EOC cells. Notably, miR-936 was able to deactivate the PI3K/Akt signaling pathway in EOC cells by regulating FGF2 both in vitro and in vivo.

Conclusion

Altogether, our findings provided initial evidence that miR-936 inhibits the aggressiveness of EOC cells in vitro and in vivo, at least partially, by targeting FGF2-mediated suppression of the PI3K/Akt pathway. Therefore, the miR-936/FGF2/PI3K/Akt pathway is a promising therapeutic target for the treatment of EOC patients.

A Novel Drug Design Strategy: An Inspiration from Encaging Tumor by Metallofullerenol Gd@C82(OH)22

Cancer remains a major threat to human health worldwide. Cytotoxicity has imposed restrictions on the conventional cytotoxic drug-based chemotherapy. The rapidly-developing nanomedicine has shown great promise in revolutionizing chemotherapy with improved efficiency and reduced toxicity. Gd@C₈₂(OH)₂₂, a novel endohedral metallofullerenol, was first reported by our research group to suppress tumor growth and metastasis efficiently without obvious toxicity. Gd@C₈₂(OH)₂₂ imprisons tumors by facilitating the formation of surrounding fibrous layers which is different from chemotherapeutics that poison tumor cells. In this review, the authors first reported the antineoplastic activity of metallofullerenol Gd@C₈₂(OH)₂₂ followed by further discussions on its new anti-cancer molecular mechanism—tumor encaging. On this basis, the unparalleled advantages of nanomedicine in the future drug design are discussed. The unique interaction modes of Gd@C₈₂(OH)₂₂ with specific targeted biomolecules may shed light on a new avenue for drug design. Depending on the surface characteristics of target biomolecules, nanomedicine, just like a transformable and dynamic key, can self-assemble into suitable shapes to match several locks for the thermodynamic stability, suggesting the target-tailoring ability of nanomedicine.

Downregulation of BAG3 attenuates cisplatin resistance by inhibiting autophagy in human epithelial ovarian cancer cells

Epithelial ovarian cancer (EOC) is one of the most common malignant gynecological tumors. Interval cytoreductive surgery and cisplatin-based chemotherapy are the standard treatments. However, acquired resistance to cisplatin presents a major challenge for improving the overall survival and prognosis of patients. Recent evidence indicates that cytoprotective functions of autophagy in cancer cells is a potential mechanism for chemoresistance. The present study aimed to investigate the mechanisms responsible for cisplatin resistance in EOC cell lines. The results revealed that cisplatin activated autophagy, measured by an increase in the expression of LC3-II by western blot analysis, protecting ovarian cancer cells from cisplatin toxicity. The present study also identified Bcl-2-associated athanogene 3 (BAG3) as a novel autophagy regulator that serves a role in cisplatin resistance. Treatment with cisplatin was observed to enhance BAG3 expression in parental and cisplatin-resistant ovarian cancer cell lines, and the downregulation of BAG3 blocked cisplatin-induced autophagy, thereby increasing cisplatin sensitivity in the EOC cell lines. In conclusion, BAG3 attenuates cisplatin resistance by inhibiting autophagy, suggesting that downregulation of BAG3 may be a useful therapeutic strategy to overcome cisplatin resistance by preventing cytoprotective autophagy in EOC.

Curcumin induces apoptotic cell death and protective autophagy by inhibiting AKT/mTOR/p70S6K pathway in human ovarian cancer cells

PURPOSE

Curcumin (Cur), a yellow-colored dietary flavor from the plant (Curcuma longa), has been demonstrated to potentially resist diverse diseases, including ovarian cancer, but drug resistance becomes a major limitation of its success clinically. The key molecule or mechanism associated with curcumin resistance in ovarian cancer still remains unclear. The aim of our study was to investigate the effects of curcumin on autophagy in ovarian cancer cells and elucidate the underlying mechanism.

METHODS

In our study, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), EdU proliferation assay and colony-forming assay were used to assess cell viability. Apoptosis was detected by western blot and flow cytometric analysis of apoptosis. Autophagy was defined by both electron microscopy and immunofluorescence staining markers such as microtubule-associated protein 1 light chain 3 (LC3). Plasmid construction and shRNA transfection helped us to confirm the function of curcumin.

RESULTS

Curcumin reduced cell viability and induced apoptotic cell death by MTT assay in human ovarian cancer cell lines SK-OV-3 and A2780 significantly. Electron microscopy, western blot and immunofluorescence staining proved that curcumin could induce protective autophagy. Moreover, treatment with autophagy-specific inhibitors or stable knockdown of LC3B by shRNA could markedly enhance curcumin-induced apoptosis. Finally, the cells transiently transfected with AKT1 overexpression plasmid demonstrated that autophagy had a direct relationship with the AKT/mTOR/p70S6K pathway.

CONCLUSIONS

Curcumin can induce protective autophagy of human ovarian cancer cells by inhibiting the AKT/mTOR/p70S6K pathway, indicating the synergistic effects of curcumin and autophagy inhibition as a possible strategy to overcome the limits of current therapies in the eradication of epithelial ovarian cancer.

Low Expression of Protocadherin-8 Promotes the Progression of Ovarian Cancer

OBJECTIVE

Ovarian cancer (OC) is the second most lethal gynecological cancer among women throughout the world. Protocadherin-8 (PCDH8) could function as a candidate tumor suppressor. However, the link between PCDH8 and OC development is poorly understood.

MATERIALS AND METHODS

A total of 68 OC patients were retrospectively enrolled. Clinical information was collected and cancer tissues were used for tissue microarray. The PCDH8 expression was determined on tissue microarray by immunohistochemical staining, and PCDH8 protein was detected in cancer tissues and adjacent tissue by western blotting. Human OC cell lines (SKOV-3 and OVCAR-3) were used to assess the effects of PCDH8 overexpression by western blot and real-time PCR analysis. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cell proliferation assay, wound healing migration assay, colony formation assay and invasion assays were performed to assess the influence of PCDH8 on cell function. Cells with Luc-nonspecific Lentiviral or Luc-Lentiviral with PCDH8 gene were subcutaneously injected into nude mice to observe the effect of PCDH8 gene on tumor growth. Bioluminescence imaging was used to observe tumor volume.

RESULTS

We found a low expression of PCDH8 in OC tissues versus the corresponding adjacent tissue. The PCDH8 expression, International Federation of Gynecology and Obstetrics stage, metastasis and recurrence were the independent prognostic factors for over-all survival by multivariate analyses. Furthermore, the patients with recurrence presented a low level of PCDH8 in OC tissues, and patients with advanced tumor stage also had a low PCDH8 expression. Importantly, the low expression of PCDH8 in OC tissues had a poor prognosis with a low overall survival rate. Overexpression of PCDH8 could inhibit OC cell growth/proliferation, migration, invasion, and colony formation in vitro. In vivo experiments also proved that overexpression of PCDH8 could inhibit OC cell growth/proliferation.

CONCLUSIONS

Protocadherin-8 might be considered as a candidate tumor suppressor and play a crucial role in the progression of OC.

Determination of the DNA binding properties of a novel PARP inhibitor MK-4827 with calf-thymus DNA by molecular simulations and detailed spectroscopic investigations

The binding interaction of niraparib (MK-4827), a poly(ADP-ribose) polymerase inhibitor, with calf thymus deoxyribonucleic acid (ctDNA) has been explored by various theoretical and experimental techniques.

Human Wharton's Jelly Stem Cell (hWJSC) Extracts Inhibit Ovarian Cancer Cell Lines OVCAR3 and SKOV3 in vitro by Inducing Cell Cycle Arrest and Apoptosis

Ovarian cancer is a highly lethal and the second highest in mortality among gynecological cancers. Stem cells either naïve or engineered are reported to inhibit various human cancers in both in-vitro and in-vivo. Herein we report the cancer inhibitory properties of human Wharton's jelly stem cell (hWJSC) extracts, namely its conditioned medium (hWJSC-CM) and cell lysate (hWJSC-CL) against two ovarian cancer cell lines (OVCAR3 and SKOV3) in-vitro. Cell metabolic activity assay of OVCAR3 and SKOV3 cells treated with hWJSC-CM (12.5, 25, 50, 75, 100%) and hWJSC-CL (5, 10, 15, 30, and 50 μg/ml) demonstrated concentration dependent inhibition at 24-72 h. Morphological analysis of OVCAR3 and SKOV3 cells treated with hWJSC-CM (50, 75, 100%) and hWJSC-CL (15, 30, and 50 μg/ml) for 24-72 h showed cell shrinkage, membrane damage/blebbings and cell death. Cell cycle assay demonstrated an increase in the sub-G1 and G2M phases of cell cycle following treatment with hWJSC-CM (50, 75, 100%) and hWJSC-CL (10, 15, and 30 μg/ml) at 48 h. Both OVCAR3 and SKOV3 cells demonstrated mild positive expression of activated caspase 3 following treatment with hWJSC-CM (50%) and hWJSC-CL (15 μg/ml) for 24 h. Cell migration of OVCAR3 and SKOV3 cells were inhibited following treatment with hWJSC-CM (50%) and hWJSC-CL (15 μg/ml) for 48 h. Tumor spheres (TS) of OVCAR3 and SKOV3 treated with hWJSC-CM (50, 75, 100%) and hWJSC-CL (10, 15, 30 μg/ml) for 48 h showed altered surface changes including vacuolations and reduction in size of TS. TS of OVCAR3 and SKOV3 also showed the presence of few ovarian cancer stem cells (CSCs) in minimal numbers following treatment with hWJSC-CM (50%) or hWJSC-CL (15 μg/ml) for 48 h. Real-time gene expression analysis of OVCAR3 and SKOV3 treated with hWJSC-CM (50%) or hWJSC-CL (15 μg/ml) for 48 h demonstrated decreased expression of cell cycle regulatory genes (cyclin A2, Cyclin E1), prostaglandin receptor signaling genes (EP2, EP4) and the pro-inflmmatory genes (IL-6, TNF-α) compared to untreated controls. The results indicate that hWJSC-CM and hWJSC-CL inhibit ovarian cancer cells at mild to moderate levels by inducing cellular changes, cell cycle arrest, apoptosis, decreasing the expression of CSC markers and related genes regulation. Therefore, the stem cell factors in hWJSCs extracts can be useful in cancer management.

Microarray-based identification of genes associated with prognosis and drug resistance in ovarian cancer

The outcome for patients with ovarian cancer (OC) is poor because of drug resistance. Therefore, identification of factors that affect drug resistance and prognosis in OC is needed. In the present study, we identified 131 genes significantly dysregulated in 90 platinum-resistant OC tissues compared with 197 sensitive tissues, of which 30 were significantly associated with disease-free survival (DFS; n = 16), overall survival (OS; n = 6), or both (n = 8) in 489 OC patients of the The Cancer Genome Atlas cohort. Of these 30 genes, 17 were significantly upregulated and 13 were downregulated in the 90 resistant tissues, and with one exception, all of the up-/downregulated genes in resistant tissues were predictors of shorter DFS or/and OS. LAX1, MECOM, and PDIA4 were independent risk factors for DFS, and KLF1, SLC7A11, and PDIA4 for OS; combining these genes provided more accurate predictions for DFS and OS than any of the genes used individually. We further verified downregulation of PDIA4 protein in 51 specimens of patients with OC (24 drug resistant's and 27 sensitive's), which confirmed that downregulated PDIA4 predicted DFS and OS. PDIA4 also consistently predicted OS in a larger sample of 1656 patients with OC. These 30 genes, particularly the PDIA4, could be therapeutic targets or biomarkers for managing OC.

Escin-induced DNA damage promotes escin-induced apoptosis in human colorectal cancer cells via p62 regulation of the ATM/γH2AX pathway

Escin, a triterpene saponin isolated from horse chestnut seed, has been used to treat encephaledema, tissue swelling and chronic venous insufficiency. Recent studies show that escin induces cell cycle arrest, tumor proliferation inhibition and tumor cell apoptosis. But the relationship between escin-induced DNA damage and cell apoptosis in tumor cells remains unclear. In this study, we investigated whether and how escin-induced DNA damage contributed to escin-induced apoptosis in human colorectal cancer cells. Escin (5-80 μg/mL) dose-dependently inhibited the cell viability and colony formation in HCT116 and HCT8 cells. Escin treatment induced DNA damage, leading to p-ATM and γH2AX upregulation. Meanwhile, escin treatment increased the expression of p62, an adaptor protein, which played a crucial role in controlling cell survival and tumorigenesis, and had a protective effect against escin-induced DNA damage: knockdown of p62 apparently enhanced escin-induced DNA damage, whereas overexpression of p62 reduced escin-induced DNA damage. In addition, escin treatment induced concentration- and time-dependent apoptosis. Similarly, knockdown of p62 significantly increased escin-induced apoptosis in vitro and produced en escin-like antitumor effect in vivo. Overexpression of p62 decreased the rate of apoptosis. Further studies revealed that the functions of p62 in escin-induced DNA damage were associated with escin-induced apoptosis, and p62 knockdown combined with the ATM inhibitor KU55933 augmented escin-induced DNA damage and further increased escin-induced apoptosis. In conclusion, our results demonstrate that p62 regulates ATM/γH2AX pathway-mediated escin-induced DNA damage and apoptosis.

P-glycoprotein targeted and near-infrared light-guided depletion of chemoresistant tumors

Drug resistance remains a formidable challenge to cancer therapy. P-glycoprotein (Pgp) contributes to multidrug resistance in numerous cancers by preventing accumulation of anticancer drugs in cancer cells. Strategies to overcome this resistance have been vigorously sought for over 3 decades, yet clinical solutions do not exist. The main reason for the failure is lack of cancer specificity of small-molecule Pgp inhibitors, thus causing severe toxicity in normal tissues. In this study, Pgp-targeted photodynamic therapy (PDT) was developed to achieve superior cancer specificity through antibody targeting plus locoregional light activation. Thus, a Pgp monoclonal antibody was chemically modified with IR700, a porphyrin photosensitizer. In vitro studies showed that the antibody-photosensitizer conjugates specifically bind to Pgp-expressing drug resistant cancer cells, and caused dramatic cytotoxicity upon irradiation with a near infrared light. We then tested our Pgp-targeted approach in mouse xenograft models of chemoresistant ovarian cancer and head and neck cancer. In both models, targeted PDT produced rapid tumor shrinkage, and significantly prolonged survival of tumor-bearing mice. We conclude that our targeted PDT approach produces molecularly targeted and spatially selective ablation of chemoresistant tumors, and thereby provides an effective approach to overcome Pgp-mediated multidrug resistance in cancer, where conventional approaches have failed.

Novel oxazolinoanthracyclines as tumor cell growth inhibitors-Contribution of autophagy and apoptosis in solid tumor cells death

Chemical modification of known, effective drugs are one method to improve the chemotherapy of tumors. We reported ability of oxazoline analogs of doxorubicin (O-DOX) and daunorubicin (O-DAU) to induce apoptosis and autophagy in ovarian and liver cancer cells. Reactive oxygen and nitrogen species (ROS and RNS, respectively), together with intracellular calcium-mediated downstream signaling, are essential for the anticancer effect of these new anthracycline analogs. The changes of mitochondrial membrane potential and induction of the ceramide pathway suggests that these compounds induce cell death by apoptosis. In addition, a significant increase of autophagosome formation was observed by fluorescence assay and acridine orange staining, indicating that the new analogs also induce autophagic cell death. Compared to free DOX- and DAU-treated cells, we observed inhibition of colony formation and migration, a time-dependency between ROS/RNS levels and a greater fall in mitochondrial membrane potential. Altogether, our research broadens the base of molecular oxazolinoanthracyclines targets and reveals that derivatives mediated oxidative stress, ceramide production and increase in intracellular calcium level by mitochondria. Furthermore, our data highlight the importance of mitochondria that simultaneously assume the role of activator of autophagy and apoptosis signals.

MicroRNA-138 inhibits SOX12 expression and the proliferation, invasion and migration of ovarian cancer cells

The aim of the present study was to investigate the expression and biological functions of microRNA (miR)-138 in ovarian cancer at the tissue and cellular levels, as well as its underlying mechanisms. A total of 47 patients with ovarian cancer were included in the present study. Ovarian cancer tissues were subjected to staging classification according to the FIGO 2000 criteria. Lymphatic metastasis was also examined. Ovarian cancer A2780 cells were transfected using liposomes. Reverse transcription-quantitative polymerase chain reaction was used to measure the expression of miR-138. A Cell-Counting Kit 8 assay was used to examine cell viability, while a Transwell assay was employed to study cell invasion and migration. The effects of miR-138 on SOX12 protein expression were examined by western blot analysis. A dual luciferase reporter assay was performed to identify the direct interaction between miR-138 and SOX12 gene. Expression of miR-138 was downregulated in ovarian cancer tissues. The level of miR-138 in patients with ovarian cancer with lymphatic metastasis was significantly lower compared with patients without lymphatic metastasis. However, expression of miR-138 was not associated with the stage of ovarian cancer. Upregulation of miR-138 inhibited the proliferation and suppressed the invasion and migration of A2780 cells. SOX12 promoted the proliferation, invasion and migration of A2780 cells. In addition, miR-138 downregulated the expression of SOX12 via binding with the 3′-UTR of SOX12 gene. The present study demonstrates that miR-138 expression is downregulated in ovarian cancer tissues and miR-138 acts as a tumor suppressor gene by inhibiting SOX12 expression and the proliferation, invasion and migration of ovarian cancer cells.

Immune Curbing of Cancer Stem Cells by CTLs Directed to NANOG

Cancer stem cells (CSCs) have been identified as the source of tumor growth and disease recurrence. Eradication of CSCs is thus essential to achieve durable responses, but CSCs are resistant to current anti-tumor therapies. Novel therapeutic approaches that specifically target CSCs will, therefore, be crucial to improve patient outcome. Immunotherapies, which boost the body's own immune system to eliminate cancerous cells, could be an alternative approach to target CSCs. Vaccines of dendritic cells (DCs) loaded with tumor antigens can evoke highly specific anti-tumor T cell responses. Importantly, DC vaccination also promotes immunological memory formation, paving the way for long-term cancer control. Here, we propose a DC vaccination that specifically targets CSCs. DCs loaded with NANOG peptides, a protein required for maintaining stem cell properties, could evoke a potent anti-tumor immune response against CSCs. We hypothesize that the resulting immunological memory will also control newly formed CSCs, thereby preventing disease recurrence.

Bufalin reverses ABCB1-mediated drug resistance in colorectal cancer

Multidrug resistance (MDR), mainly mediated by ABCB1 transporter, is a major cause for chemotherapy failure. Bufalin (BU), an active component of the traditional Chinese medicine chan’su, has been reported to have antitumor effects on various types of cancer cells. The purpose of this present study was to investigate the reversal effect of BU on ABCB1-mediated multidrug resistance in colorectal cancer. BU at safe concentration (5, 10, 20 nM) could reverse chemosensitivity of ABCB1-overexpression HCT8/ADR, LoVo/ADR and HCT8/ABCB1 nearly back to their parental cells level. In addition, results from the drug accumulation studies revealed that BU was able to enhance intracellular accumulation of doxorubicin (DOX) and Rhodamine 123 (Rho-123) in a dose-dependent manner. Furthermore, Western blot assays showed that BU significantly inhibited the expression level of ABCB1 protein. Meanwhile, BU stimulated the ATPase activity of ABCB1, which suggested that BU might be a substrate of ABCB1. More interestingly, docking analysis predicted that BU could be docked into the large hydrophobic drug-binding cavity of human ABCB1. Importantly, BU remarkable increased the effect of DOX against the ABCB1 resistant HCT8/ADR colorectal cell xenografts in nude mice, without inducing any obvious toxicity. Overall, we concluded that BU efficiently reversed ABCB1-mediated MDR through not only inhibited the efflux function of ABCB1, but also down-regulate its protein expression, which might represent a potential and superior ABCB1 modulator in colorectal cancer.

MicroRNA-519a inhibits the proliferation and promotes the apoptosis of ovarian cancer cells through targeting signal transducer and activator of transcription 3

Ovarian cancer is a highly prevalent cancer among women. Recent studies have indicated that microRNAs (miRs) may serve important roles in the pathogenesis of ovarian cancer. miR-519a was observed to be downregulated in tissue samples of patients with ovarian cancer; however, its role in ovarian cancer requires further investigation. The aim of the present study was to examine the role of miR-519a in the pathogenesis of ovarian cancer and determine its direct target. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to examine the expression of miR-519a in 20 patients ovarian cancer and 20 normal ovarian tissue samples. Subsequently, SKOV3 cells were cultured and transfected with miR-519a mimics, while MTT and Annexin V assays were performed to investigate the role of miR-519a in the proliferation and apoptosis of SKOV3 cells. In addition, RT-qPCR and western blotting were used to determine the expression levels of miR-519a, signal transducer and activator of transcription 3 (STAT3), myeloid cell leukemia 1 (Mcl-1) and B-cell lymphoma-extra large (Bcl-xl) in untransfected and miR-519a mimic-transfected SKOV3 cells. Dual-luciferase reporter assay was also performed to confirm whether STAT3 was a direct target of miR-519a. The results revealed that miR-519a was significantly downregulated in tissue samples of patients with ovarian cancer as compared with the normal ovarian tissues. Furthermore, transient overexpression of miR-519a inhibited the proliferation and promoted the apoptosis of SKOV3 cells, as well as decreased the mRNA and protein expression levels of STAT3, Mcl-1 and Bcl-xl. Finally, dual-luciferase reporter assay confirmed that STAT3 was a direct target of miR-519a. In conclusion, the present study proved for the first time that miR-519a functions as a tumor suppressor by targeting STAT3 in ovarian cancer, suggesting that miR-519a may be a potential biomarker for the diagnosis and treatment of ovarian cancer.

Discovering drugs to overcome chemoresistance in ovarian cancers based on the cancer genome atlas tumor transcriptome profile

Ovarian cancer accounts for the highest mortality among gynecologic cancers, mainly due to intrinsic or acquired chemoresistance. While mechanistic-based methods have been used to identify compounds that can overcome chemoresistance, an effective comprehensive drug screening has yet to be developed. We applied a transcriptome based drug sensitivity prediction method, to the Cancer Genome Atlas (TCGA) ovarian cancer dataset to impute patient tumor response to over 100 different drugs. By stratifying patients based on their predicted response to standard of care (SOC) chemotherapy, we identified drugs that are likely more sensitive in SOC resistant ovarian tumors. Five drugs (ABT-888, BIBW2992, gefitinib, AZD6244 and lenalidomide) exhibit higher efficacy in SOC resistant ovarian tumors when multi-platform of transcriptome profiling methods were employed. Additional in vitro and clinical sample validations were carried out and verified the effectiveness of these agents. Our candidate drugs hold great potential to improve clinical outcome of chemoresistant ovarian cancer.

Synthesis of Homoverrucosanoid-Derived Esters and Evaluation as MDR Modulators

The synthesis of the A-B-cis,B-C-trans-annulated cyclohepta[e]hydrindane core of a gagunin E analogue is reported in detail. The tricarbocyclic scaffold was assembled starting from an easily accessible A ring building block by a (4 + 2)-cycloaddition for annulation of the B ring. A ring-closing metathesis served for construction of the seven-membered C ring. The angular methyl groups were attached by electrophilic cyclopropanation-ring opening. A library based on the most active lead compound was made accessible by esterification of the terpenols with commercially available acids. A transannular etherification reaction gave access to tetracyclic derivatives of the synthetic inhibitors. The members of the compound library of non-natural homoverrucosanoid-derived esters were examined as modulators of the membrane transporter proteins ABCB1 (P-gp), ABCG2 (BCRP), and ABCC1 (MRP1), which are involved in the formation of multidrug resistance (MDR) in cancer chemotherapy.

Tobacco Mosaic Virus-Delivered Cisplatin Restores Efficacy in Platinum-Resistant Ovarian Cancer Cells

Platinum resistance in ovarian cancer is the major determinant of disease prognosis. Resistance can first appear at the onset of disease or develop in response to platinum-based chemotherapy. Due to poor response to alternate chemotherapies and lack of targeted therapies, there is an urgent clinical need for a new avenue toward treatment of platinum-resistant (PR) ovarian cancer. Nanoscale delivery systems hold potential to overcome resistance mechanisms. In this work, we present tobacco mosaic virus (TMV) as a nanocarrier for cisplatin for treatment of PR ovarian cancer cells. The TMV-cisplatin conjugate (TMV-cisPt) was synthesized using a charge-driven reaction that, like a classic click reaction, is simple and reliable for large-scale production. Up to ∼1900 cisPt were loaded per TMV-cisPt with biphasic release profiles characterized by a fast half-life ( t₁) of ∼1 h and slow half-life ( t₂) of ∼12 h independent of pH. Efficient cell uptake of TMV was observed when incubated with ovarian cancer cells, and TMV-cisPt demonstrated superior cytotoxicity and DNA double strand breakage (DSB) in platinum-sensitive (PS) and PR cancer cells when compared to free cisplatin. The cytotoxicity in PR ovarian cancer cells and overall lower effective dosage requirement makes TMV-cisPt a powerful candidate for improved ovarian cancer treatment strategies.

Investigating isoquinoline derivatives for inhibition of inhibitor of apoptosis proteins for ovarian cancer treatment

Objective

To discover novel isoquinoline derivatives for inhibition of inhibitor of apoptosis proteins (IAP) for the treatment of ovarian cancer.

Methods

We first synthesized 533 isoquinoline derivatives, and screened them using CCK-8 to measure their antiproliferative activity. These compounds were further tested by Hoechst staining and flow cytometric analysis to assess proapoptotic activity. The in vivo antitumor efficacy and safety of the screened compounds were evaluated on the xenograft mouse model. Ki-67 staining and TUNEL assay were used to evaluate proliferation and apoptosis in the resected tumors, respectively. Western blot and polymerase chain reaction (PCR) were conducted to evaluate the levels of proliferating cell nuclear antigen (PCNA), caspase-3, PARP, and IAP in resected tumors.

Results

Compound B01002 and C26001 displayed antiproliferative and proapoptotic activity on SKOV3 ovarian cancer with an IC50 of 7.65 and 11.68 µg/mL, respectively. Both compounds inhibited tumor growth in a xenografted mouse model with good safety profiles, and tumor growth inhibition (TGI) of B01002 and C26001 was 99.53% and 84.23%, respectively. Resected tumors showed that both compounds inhibited tumor cell proliferation and induced apoptosis in vivo. Caspase-3 and PARP were activated, whereas IAP proteins were downregulated at the protein level.

Conclusion

Compound B01002 and C26001 could inhibit ovarian tumor growth and promote tumor apoptosis, partly by downregulating the IAPs, and, thus, might be promising candidates for treatment of ovarian cancer.