Drug Resistance Protein Research Articles

Coordination of fungal biofilm development by extracellular vesicle cargo

The fungal pathogen Candida albicans can form biofilms that protect it from drugs and the immune system. The biofilm cells release extracellular vesicles (EVs) that promote extracellular matrix formation and resistance to antifungal drugs. Here, we define functions for numerous EV cargo proteins in biofilm matrix assembly and drug resistance, as well as in fungal cell adhesion and dissemination. We use a machine-learning analysis of cargo proteomic data from mutants with EV production defects to identify 63 candidate gene products for which we construct mutant and complemented strains for study. Among these, 17 mutants display reduced biofilm matrix accumulation and antifungal drug resistance. An additional subset of 8 cargo mutants exhibit defects in adhesion and/or dispersion. Representative cargo proteins are shown to function as EV cargo through the ability of exogenous wild-type EVs to complement mutant phenotypic defects. Most functionally assigned cargo proteins have roles in two or more of the biofilm phases. Our results support that EVs provide community coordination throughout biofilm development in C. albicans.

Knockdown lncRNA CRNDE enhances temozolomide chemosensitivity by regulating autophagy in glioblastoma

BackgroundThe regulatory roles of long non-coding RNA (lncRNA) CRNDE in temozolomide (TMZ) chemoresistance to glioblastoma multiforme (GBM) are still poorly understood. Therefore, the function, characteristics, and possible mechanism of CRNDE in TMZ-induced chemoresistance to GBM were explored.MethodsFirstly, the expression level of CRNDE in 58 cases of glioma tissue specimens and 30 cases of normal brain tissues were tested by qRT-PCR. Meanwhile, the correlation between CRNDE expression level, the clinicopathological characteristics, and survival time of patients with glioma were analyzed. Then, the CRNDE expression in various glioma cell lines was detected, and CRNDE knockdown cell models were constructed. Subsequently, to explore the effect of CRNDE on chemosensitivity to TMZ, cell viability was detected by the CCK-8 assay and IC50 values, and cell proliferation was detected by cell clone assay and EdU assay, as well as cell survival was detected by apoptosis with flow cytometry under TMZ treatment. Further, the expression of drug-resistance protein ABCG2, autophagy related proteins, and PI3K/Akt/mTOR pathway were measured by western blot or qRT-PCR in TMZ-treated glioma cells. Finally, the mouse tumor xenograft model was established and the tumor volume and weight were measured, and ABCG2 expression was conducted by immunohistochemistry assay.ResultsThe integrated results demonstrated lncRNA CRNDE was a poor prognosis factor for GBM patient, which was upregulated in patients who were resistant to TMZ, and closely associated with chemotherapeutic response status to TMZ treatment. Further, functional assays revealed that knockdown of CRNDE could notably reduce glioma cell viability and proliferation, and elevate cell apoptosis to enhance the chemosensitivity to TMZ in vitro and in vivo. Mechanistically, the depression of CRNDE could diminish the expression of LC3 II/I, Beclin1 and Atg5 and increase the p62 expression level to inhibit autophagy due to the activation of PI3K/Akt/mTOR pathway as well as highly correlated with ABCG2 expression.ConclusionsOverall, the study provided that lncRNA CRNDE is a reliable clinical predictor of outcome and prognosis and a potential biomarker for predicting TMZ treatment response in GBM by modulating the autophagy through PI3K/Akt/mTOR pathway and ABCG2 expression which may be a novel therapeutic target for regulating TMZ sensitivity to GBM.

GWAS provides biological insights into mechanisms of the parasitic plant (Striga) resistance in sorghum

BackgroundSorghum yields in sub-Saharan Africa (SSA) are greatly reduced by parasitic plants of the genus Striga (witchweed). Vast global sorghum genetic diversity collections, as well as the availability of modern sequencing technologies, can be potentially harnessed to effectively manage the parasite.ResultsWe used laboratory assays – rhizotrons to screen a global sorghum diversity panel to identify new sources of resistance to Striga; determine mechanisms of resistance, and elucidate genetic loci underlying the resistance using genome-wide association studies (GWAS). New Striga resistant sorghum determined by the number, size and biomass of parasite attachments were identified. Resistance was by; i) mechanical barriers that blocked parasite entry, ii) elicitation of a hypersensitive reaction that interfered with parasite development, and iii) the inability of the parasite to develop vascular connections with hosts. Resistance genes underpinning the resistance corresponded with the resistance mechanisms and included pleiotropic drug resistance proteins that transport resistance molecules; xylanase inhibitors involved in cell wall fortification and hormonal regulators of resistance response, Ethylene Response Factors.ConclusionsOur findings are of fundamental importance to developing durable and broad-spectrum resistance against Striga and have far-reaching applications in many SSA countries where Striga threatens the livelihoods of millions of smallholder farmers that rely on sorghum as a food staple.

Exploring Drug and Antibody-Based Treatment Options for Creutzfeldt-Jakob Disease

Creutzfeldt-Jakob Disease (CJD) is a neurodegenerative disease characterized by mutant PrP prion proteins, which accumulates and impairs the function of wild-type PrPc proteins. The interaction of prion proteins with wild-type proteins converts the PrPc proteins to mutant PrP proteins. These mutant prion proteins lead to neural tissue degradation and other nervous system problems that can eventually lead to death. The use of antibodies to target and destroy prion proteins can be used to decrease PrP levels that can stop CJD progression. The binding affinities of different anti-PrP Fab antibodies are analyzed to determine which antibody best binds to PrP proteins and targets them for destruction. Through antibody-based targeting of prion proteins, potential treatment methods could be developed for CJD. In addition, the use of drugs, such as quinacrine and doxycycline, also show short-term effects in decreasing the progression of CJD. These drugs extend the average lifespan of tested subjects with CJD but also lead to the development of drug-resistant prion proteins that eventually cause the death of the subject affected by CJD.

Pulmonary surfactants affinity Pluronic-hybridized liposomes enhance the treatment of drug-resistant lung cancer

For a long time, the incidence and mortality of lung cancer have ranked first among all kinds of cancers, of which the major type is non-small cell lung cancer (NSCLC). Until now, chemotherapy and radiotherapy are still the first choice for patients with advanced or metastatic NSCLC. However, the emergence of multi-drug resistance (MDR) always leads to the failure of chemotherapy and increases cancer-related mortality. In this study, we prepared a Pluronic-hybridized paclitaxel-loaded liposome (PPL), which was used in combination with ambroxol (Ax) to not only resensitize drug-resistant tumor cells, but also increase the preparation retention in the lung. On the one hand, Ax induced the production of pulmonary surfactants (PS) and responsively improved the accumulation of pulmonary surfactants affinity liposomes whose skeleton was exogenous pulmonary surfactant phospholipids DPPC, because of the specific affinity of phospholipids related to pulmonary surfactant proteins. On the other hand, drug-resistant tumor cells were resensitized due to the inhibition of autophagy by Ax and the reduced expression of the drug-resistant protein P-glycoprotein (P-gp) by Pluronic P105. Therefore, we concluded that the combination of PPL and Ax achieved excellent killing tumor effects through multi-path and multi-strategy, having great application prospects in the future.

Emodin-loaded polymer-lipid hybrid nanoparticles enhance the sensitivity of breast cancer to doxorubicin by inhibiting epithelial\u2013mesenchymal transition

BackgroundThe role of epithelial–mesenchymal transition (EMT) involved in breast cancer metastasis and chemoresistance has been increasingly recognized. However, it is necessary to search for more effective strategies to inhibit EMT thereby increase the sensitivity of breast cancer cells to chemotherapy drugs. Emodin has a potential in overcoming tumor drug resistance and restraining the development of EMT, but the poor internalization into breast cancer cells limited the application.ResultsMCF-7/ADR cells have more EMT characteristics than MCF-7 cell. EMT in MCF-7/ADR cells promotes the development of drug resistance via apoptosis resistance and facilitating the expression of P-gp. The anti-cancer effect of DOX enhanced by the decreasing of drug resistance protein P-gp and apoptosis-related proteins after EMT inhibited in MCF-7/ADR cells. E-PLNs increase the cellular uptake of EMO and restore DOX sensitivity in MCF-7/ADR cells by inhibiting EMT.ConclusionE-PLNs inhibit EMT to enhance the sensitivity of breast cancer to DOX. The combination of E-PLNs and DOX can improve the efficacy of DOX in the treatment of breast cancer, which provides a new method to prevent or delay clinical drug resistance.

Paeoniflorin and albiflorin regulate P-gp-mediated aconitine and hypaconitine transport through an Madin Darby canine kidney-multi drug resistance protein 1 cell model

Aconitine and hypaconitine are the main active ingredients of Radix Aconiti, paeoniflorin and albiflorin are the primary components of Radix Paeoniae Alba. Both Radix Aconiti and Radix Paeoniae Alba are herbs that are commonly used in traditional Chinese medicine. This study sought to explore the mechanistic transport of aconitine and hypaconitine across MDCK-MDR1 cells and to assess the effect of paeoniflorin and albiflorin on aconitine and hypaconitine transmembrane transport as a potential attenuation mechanism. Drug cytotoxicity was tested via the MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, and transport studies were performed in both directions. The effects of drugs on P-gp ATPase activity, P-gp efflux function, MDR1 mRNA and P-gp expression were evaluated in MDCK-MDR1 cells. Aconitine and hypaconitine treatment with the verapamil could significantly decrease the efflux rate (ER). The ER of aconitine and hypaconitine were significantly increased with the coadministration of paeoniflorin and albiflorin, suggesting that paeoniflorin and albiflorin can promote the efflux of these two alkaloids. Aconitine and hypaconitine can induce P-gp enzymatic activity, inhibit P-gp-mediated efflux, and downregulate the expression of P-gp protein to produce cytotoxic effects. When treatment in combination with paeoniflorin and albiflorin, it could stimulated P-gp ATPase activity, increasing mRNA expression, enhance P-gp efflux function, and upregulate P-gp protein expression.

Evaluation of KCTD12 and Cripto-1 as novel upregulated proteins participating in breast cancer development and drug resistance

Background: Potassium channel tetramerization domain containing 12 (KCTD12) showed contradictory roles in many cancers, however, its role in breast cancer is unknown. Cripto-1 participates activates the Notch signaling pathway which was inhibited by KCTD12 in esophageal squamous cell carcinoma (ESCC). Uncoordinated 51-like kinase 2 (ULK2) with established roles in cancer was negatively regulated by KCTD12. Multidrug resistance protein 1 (MDR1) promotes resistance by an active transport efflux pump. KCTD12 downregulates the expression of drug-resistant proteins as ABCC4 and ABCG2 in ESCC patients. Purpose: We investigated the markers role in the early breast cancer. Methods: Sixty-five patient’s serum samples were compared with 10 controls and 15 benign ones. Results: Higher serum levels of KCTD12, Cripto-1, MDR1, and ULK2 in all malignant cases suggesting novel roles with better sensitivity and specificity along with CA15.3, where the resistant group was the highest suggesting value for de-novo breast cancer diagnosis. Conclusion: Positive correlations for KCTD12 with Cripto-1, MDR1, and ULK2 suggesting a new role of KCTD12. The cumulated ROC curves with CA15.3 revealed better sensitivity and specificity highlighting the add on of using more than one marker.

Exploration into natural variation for genes associated with fruit shape and size among Capsicum chinense collections

Phenotype diversity within cultivated Capsicum chinense is particularly evident for fruit shape and size. We used this diversity in C. chinense to further unravel the genetic mechanisms underlying fruit shape variation in pepper and related Solanaceous species. We identified candidate genes for C. chinense fruit shape, explored their contribution to population structure, and characterized their potential function in pepper fruit shape. Using genotyping by sequencing, we identified 43,081 single nucleotide polymorphisms (SNPs) from diverse collections of C. chinense. Principal component, neighbor-joining tree, and population structure analyses resolved 3 phylogenetically robust clusters associated with fruit shapes. Genome-wide association study (GWAS) was used to identify associated genomic regions with various fruit shape traits obtained from image analysis with Tomato Analyzer software. In our GWAS, we selected 12 SNPs associated with locule number trait and 8 SNP markers associated with other fruit shape traits such as perimeter, area, obovoid, ellipsoid and morphometrics (5y, 6y and 7y). The SNPs in CLAVATA1, WD-40, Auxin receptor, AAA type ATPase family protein, and RNA polymerase III genes were the major markers identified for fruit locule number from our GWAS results. Furthermore, we found SNPs in tetratricopeptide-repeat thioredoxin-like 3, enhancer of ABA co-receptor 1, subunit of exocyst complex 8 and pleiotropic drug resistance proteins associated with various fruit shape traits. CLAVATA1, WD-40 and Auxin receptor genes are known genes that affect tomato fruit shape. In this study, we used Arabidopsis thaliana T-DNA insertion knockout mutants and expression profiles for functional characterization of newly identified genes and to understand their role in fruit shape.

The Impact of Extracellular Ca2+ and Nanosecond Electric Pulses on Sensitive and Drug-Resistant Human Breast and Colon Cancer Cells.

Simple SummaryThe drug resistance phenomenon in cancer constantly induces problems in therapeutic protocols. Pulsed electric fields (PEFs) seem to be a promising method in drug molecule delivery. Here we have proved that electroporation supported by calcium ions can alternate the activity of drug resistance proteins. Our results indicated that MDR1 expression is not significantly modified by nanosecond electroporation in multidrug-resistant cells. However, PEF significantly inhibited MDR1 activity and cell viability when combined with calcium ions.(1) Background: Calcium electroporation (CaEP) is based on the application of electrical pulses to permeabilize cells (electroporation) and allow cytotoxic doses of calcium to enter the cell. (2) Methods: In this work, we have used doxorubicin-resistant (DX) and non-resistant models of human breast cancer (MCF-7/DX, MCF-7/WT) and colon cancer cells (LoVo, LoVo/DX), and investigated the susceptibility of the cells to extracellular Ca2+ and electric fields in the 20 ns–900 ns pulse duration range. (3) Results: We have observed that colon cancer cells were less susceptible to PEF than breast cancer cells. An extracellular Ca2+ (2 mM) with PEF was more disruptive for DX-resistant cells. The expression of glycoprotein P (MDR1, P-gp) as a drug resistance marker was detected by the immunofluorescent (CLSM) method and rhodamine-123 efflux as an MDR1 activity. MDR1 expression was not significantly modified by nanosecond electroporation in multidrug-resistant cells, but a combination with calcium ions significantly inhibited MDR1 activity and cell viability. (4) Conclusions: We believe that PEF with calcium ions can reduce drug resistance by inhibiting drug efflux activity. This phenomenon of MDR mechanism disruption seems promising in anticancer protocols.

Abrogating Treatment Resistance By Mir-451 in FLT3-ITD-Positive Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a fatal malignant hematologic disorder. Although many patients with AML initially respond to standard chemotherapy and achieve complete remission (CR), the majority of patients relapse due to the development and clonal expansion of chemoresistant subclones. Albeit being a heterogenous disease, individual mutations are still scarcely considered in the current treatment regimen.Approximately 30% of AML patients exhibit gain-of-function mutations in the FMS-like tyrosine kinase 3 receptor (FLT3-receptor) gene. Here, an internal tandem duplication (ITD) in the juxtamembrane region of the receptor is among the most frequently observed mutations. This usually entails a constitutive activation of FLT3 receptor downstream signaling pathways, leading to differential gene expression patterns and aberrant cell growth. Clinically, FLT3-ITD mutations confer adverse prognosis. Thus, many promising FLT3 signaling inhibitor-based therapies are currently utilized to improve patient survival. However, the phenomenon of treatment resistant subclones persists and constantly calls for new angles of treatment.MicroRNAs, a group of small non-coding RNAs, regulate gene expression on a posttranscriptional level by a complementary binding to 3'UTRs of protein-coding mRNAs. They have been shown to influence healthy and malignant hematopoiesis and to predict treatment response in cancer. In addition, several candidates have been connected to treatment resistance or sensitivity in AML.Within this study, we hypothesized that microRNAs are biological important players in the adverse treatment response and the development of chemoresistance in FLT3-ITD associated AML.Initially, we were interested in the microRNA expression pattern in FLT3-ITD associated AML. Therefore, we performed a next generation sequencing screen in bone marrow mononuclear cells from healthy donors, AML patients with FLT3-wildtype and AML patients with FLT3-ITD mutation. Here, we identified miR-451 to be significantly lower expressed in AML compared to healthy individuals. Furthermore, it was nearly absent in FLT3-ITD associated AML. In addition, we compared our results to the AML patient cohort of “The Cancer Genome Atlas” (TCGA) and found a similar miR-451 expression distribution. In agreement with this, miR-451 expression increased during differentiation of primary human and mouse hematopoietic cells. Moreover, transduction of U937 as well as 32D cells with FLT3-ITD led to a decrease in miR-451 expression.Downregulation of miR-451 has been shown for various cancerous diseases to correlate with an increased cancer persistence as well as recurrence, as one established target of miR-451 is multi drug resistance protein 1 (MDR1). MDR1 is an ATP dependent efflux pump that mediates chemoresistance by transporting drugs out of the cell. Today, only limited data are available on the miR-451-MDR1 axis in FLT3-ITD associated AML. Thus, we hypothesized that low miR-451 expression and high MDR1 activity is associated with treatment resistance.Therefore, we showed an inverse correlation of miR-451 expression and MDR1 protein levels in various leukemic cells lines. Furthermore, we observed that a repression of FLT3-ITD signaling by both Quizartinib and Gilteritinib causes a miR-451 expression increment and a subsequent reduction of MDR1 protein levels. By luciferase activity assay, we could demonstrate a direct binding of miR-451 to the 3'UTR of MDR1. In order to investigate whether miR-451 alone is able to abrogate treatment resistance, we overexpressed miR-451 in both normal MV4;11 and treatment resistant MV4;11 cells (MV4;11-R). Subsequently, MDR1 protein levels were decreased and cells exhibited an enhanced sensitivity towards both FLT3-ITD inhibitor and chemotherapeutic agent-based treatment. Moreover, exogenous miR-451 was able to restore drug sensitivity in MV4;11-R cells comparable to that of normal MV4;11 cells. As proof of principle, MDR1 inhibitor Tariquidar mimicked miR-451-mediated effects and sensitized MV4;11-R cells to FLT3-ITD inhibitor Quizartinib.In conclusion, we identified a novel mechanism by which FLT3-ITD is able to alter treatment response and confer a poor prognosis. Hence, not only inhibiting FLT3-ITD but mimicking the effects of negatively regulated downstream targets such as miR-451 presents as promising new avenue for FLT3-ITD AML treatment. DisclosuresThiede:Bayer: Consultancy, Speakers Bureau; Roche: Consultancy; Novartis: Consultancy, Speakers Bureau; Agendix: Employment.

CXCL8 Facilitates the Survival and Paclitaxel-Resistance of Triple-Negative Breast Cancers

BackgroundThis study aimed to demonstrate CXCL8 expression in TNBC tissues and cells, and elucidate the functional mechanism of CXCL8 in paclitaxel (PTX)-resistant TNBC. MethodsBioinformatics analysis was performed to identify differentially expressed genes (DEGs) in PTX-resistant TNBC using publicly available data from the GEO, TCGA and METABRIC databases. STRING was used to identify the interacting partners of CXCL8. Kaplan-Meier software was used to analyze the relationship between CXCL8 expression and patient survival rate. The protein expression and distribution of CXCL8 were examined by immunohistochemistry, MTT assay and colony formation assay were performed to determine cell viability of TNBC cells treated with PTX. Western blotting was used to assess the levels of drug resistance and apoptosis-related proteins. GO-KEGG analysis was conducted on the DEGs to identify enriched signaling pathways. ResultsThe results of bioinformatics analysis demonstrated a high expression of CXCL8 in TNBC tissues and cells. Kaplan-Meier analysis revealed that the expression of CXCL8 is associated with poor prognosis. CXCL8 was upregulated in PTX-resistant TNBC cells. Knockdown of CXCL8 increased the sensitivity of TNBC cells to PTX. Mechanically, CXCL8 deficiency regulated PTX resistance in TNBC cells via cell apoptosis signaling pathway. ConclusionOur work demonstrated that CXCL8 may be a potential molecule to be targeted for the treatment of PTX-resistant TNBC.

Retinoblastoma tumor suppressor gene 1 enhances 5-Fluorouracil chemosensitivity through SDF-1/CXCR4 axis by regulating autophagy in gastric cancer

Due to lack of effective biomarkers for early diagnosis, most patients are diagnosed with advanced gastric cancer and have lower survival rates. 5-Fluorouracil (5-FU) is one of commonly used drugs for chemotherapy of gastric cancer, but drug resistance limits the wide application of agents. Retinoblastoma tumor suppressor gene 1 (RB1) is a key regulator in the progression of various human cancers, including gastric cancer. However, the effects of RB1 on chemosensitivity and the underlying mechanisms in gastric cancer (GC) are not clear. In this study, expressions of RB1 in GC cell lines were evaluated by RT-qPCR and western blot assay. CCK-8 was applied to examine the effect of 5-FU on cell viability. Meanwhile, IC50 values were calculated. The drug-resistance protein MDR1 and autophagy-related proteins were detected by western blot assay. Flow cytometry was used to detect cell cycle. The results showed that RB1 expressions were downregulated in GC cell lines and had significant differences between 5-FU resistance cell lines (SNU-620/5-FU and NUGC-3/5-FU) and non-resistance cell lines (SNU-620 and NUGC-3). Overexpression of RB1 enhanced 5-FU sensitivity of GC cells and caused cell cycle arrest in the S phase. Meanwhile, autophagy-related proteins were downregulated. Mechanistically, SDF-1/CXCR4 participated in the regulation of RB1 on cell autophagy. Autophagy activator, SDF-1 treatment and CXCR4 activation reversed the promoted effects of RB1 on 5-FU sensitivity in GC cells. In conclusion, our data revealed that RB1 was downregulated in GC cell lines. RB1 overexpression enhanced 5-FU chemosensitivity in GC cells by regulating cell autophagy via SDF-1/CXCR4 pathway. RB1 might serve as a promising therapeutic target of GC.

Combination therapy with miR34a and doxorubicin synergistically inhibits Dox-resistant breast cancer progression via down-regulation of Snail through suppressing Notch/NF-κB and RAS/RAF/MEK/ERK signaling pathway

Resistance to breast cancer (BCa) chemotherapy severely hampers the patient's prognosis. MicroRNAs provide a potential therapeutic prospect for BCa. In this study, the reversal function of microRNA34a (miR34a) on doxorubicin (Dox) resistance of BCa and the possible mechanism was investigated. We found that the relative level of miR34a was significantly decreased in Dox-resistant breast cancer cell MCF-7 (MCF-7/A) compared with Dox-sensitive MCF-7 cells. Transfection with miR34a significantly suppressed the invasion, migration, adhesion of MCF-7/A cells without inhibiting their growth obviously. The combination of miR34a and Dox could significantly inhibit the proliferation, migration, invasion and induce the apoptosis of MCF-7/A cells. The synergistic effect of this combination on resistant MCF-7/A cells has no obvious relation with the expressions of classical drug-resistant proteins P-GP, MRP and GST-π, while closely related with the down-regulation on TOP2A and BCRP. Moreover, we found both protein and mRNA expression of Snail were significantly up-regulated in MCF-7/A cells in comparison with MCF-7 cells. Transfection with small interfering RNA (siRNA) of Snail could inhibit the invasion, migration and adhesion of drug-resistant MCF-7/A cells, while high-expression of Snail could remarkably promote the invasion, migration and adhesion of MCF-7 cells, which might be related with regulation of N-cadherin and E-cadherin. Transfection with miR34a in MCF-7/A cells induced a decrease of Snail expression. The potential binding sites of miR34a with 3′ UTR of Snail were predicted by miRDB target prediction software, which was confirmed by luciferase reporter gene method. Results showed that the relative activity of luciferase was reduced in MCF-7/A cells after co-transfection of miR34a and wild type (wt)-Snail, while did not change by co-transfection with miR34a and 3′ UTR mutant type (mut) Snail. Combination of miR34a and Dox induced a stronger decrease of Snail in MCF-7/A cells in comparison to miR34a or Dox treatment alone. What’ more, for the first time, we also found miR34a combined with Dox could obviously inhibit the expression of Snail through suppressing Notch/NF-κB and RAS/RAF/MEK/ERK pathway in MCF-7/A cells. In vivo study indicated that combination of miR34a and Dox significantly slowed down tumor growth in MCF-7/A nude mouse xenograft model compared with Dox alone, which was manifested by the down-regulation of Snail and pro-apoptosis effect in tumor xenografts. These results together underline the relevance of miR34a-driven regulation of Snail in drug resistance and co-administration of miR34a and Dox may produce an effective therapy outcome in the future in clinic.

Extracellular Vesicles: A Novel Tool Facilitating Personalized Medicine and Pharmacogenomics in Oncology.

Biomarkers that can guide cancer therapy based on patients’ individual cancer molecular signature can enable a more effective treatment with fewer adverse events. Data on actionable somatic mutations and germline genetic variants, studied by personalized medicine and pharmacogenomics, can be obtained from tumor tissue or blood samples. As tissue biopsy cannot reflect the heterogeneity of the tumor or its temporal changes, liquid biopsy is a promising alternative approach. In recent years, extracellular vesicles (EVs) have emerged as a potential source of biomarkers in liquid biopsy. EVs are a heterogeneous population of membrane bound particles, which are released from all cells and accumulate into body fluids. They contain various proteins, lipids, nucleic acids (miRNA, mRNA, and DNA) and metabolites. In cancer, EV biomolecular composition and concentration are changed. Tumor EVs can promote the remodeling of the tumor microenvironment and pre-metastatic niche formation, and contribute to transfer of oncogenic potential or drug resistance during chemotherapy. This makes them a promising source of minimally invasive biomarkers. A limited number of clinical studies investigated EVs to monitor cancer progression, tumor evolution or drug resistance and several putative EV-bound protein and RNA biomarkers were identified. This review is focused on EVs as novel biomarker source for personalized medicine and pharmacogenomics in oncology. As several pharmacogenes and genes associated with targeted therapy, chemotherapy or hormonal therapy were already detected in EVs, they might be used for fine-tuning personalized cancer treatment.

Genome-wide characterization and expression profiling of the PDR gene family in tobacco (Nicotiana tabacum).

The pleiotropic drug resistance (PDR) proteins of the ATP-binding cassette (ABC) family play essential roles in physiological processes and have been characterized in many plant species. However, no comprehensive investigation of tobacco (Nicotiana tabacum), an important economic crop and a useful model plant for scientific research, has been presented. We identified 32 PDR genes in the tobacco genome and explored their domain organization, chromosomal distribution and evolution, promoter cis-elements, and expression profiles. A phylogenetic analysis revealed that tobacco has a significantly expanded number of PDR genes involved in plant defense. It also revealed that two tobacco PDR proteins may function as strigolactone transporters to regulate shoot branching, and several NtPDR genes may be involved in cadmium transport. Moreover, tissue expression profiles of NtPDR genes and their responses to several hormones and abiotic stresses were assessed using quantitative real-time PCR. Most of the NtPDR genes were regulated by jasmonate or salicylic acid, suggesting the important regulatory roles of NtPDRs in plant defense and secondary metabolism. They were also responsive to abiotic stresses, like drought and cold, and there was a strong correlation between the presence of promoter cis-elements and abiotic/biotic stress responses. These results provide useful clues for further in-depth studies on the functions of the tobacco PDR genes.

The Role of RNA Modifications and RNA-modifying Proteins in Cancer Therapy and Drug Resistance

The Role of RNA Modifications and RNA-modifying Proteins in Cancer Therapy and Drug Resistance

MicroRNA-95-3p serves as a contributor to cisplatin resistance in human gastric cancer cells by targeting EMP1/PI3K/AKT signaling.

MicroRNAs (miRNAs) are thought to be involved in the development of cisplatin (DDP) resistance in gastric cancer (GC). Using RNA sequencing analysis (RNA-seq), we found that miR-95-3p is associated with DDP resistance in GC. We discovered that miR-95-3p is highly expressed in DDP-resistant GC tissues and cell lines (SGC7901/DDP and AGS/DDP). Furthermore, results from the BrdU and MTT assays indicated that miR-95-3p promotes GC cell proliferation. Additionally, data from transwell chamber assay, wound healing test and in vivo experiments illustrated that miR-95-3p can effectively promote invasion, migration and tumorigenic capacity, respectively, of DDP-resistant GC cells. Subsequently, results from dual luciferase assay and qRT-PCR collectively indicated that EMP1 is a target of miR-95-3p with inhibitory function through suppression of the EMT process and drug-resistance proteins. Furthermore, PI3K/AKT was identified as a downstream pathway of miR-95-3p, which promotes DDP resistance in GC. In summary, miR-95-3p helped develop DDP-resistance through down-regulation of EMP1 and increasing phosphorylation of the PI3K/Akt pathway in GC.

Knockdown of sorcin increases HEI-OC1 cell damage induced by cisplatin in vitro

Hearing loss caused by ototoxic drugs is a kind of acquired hearing loss. Cisplatin is one of the most commonly used drugs and its main action sites are hair cells (HCs). Sorcin is a drug-resistant calcium-binding protein belonging to the small penta-EF-hand protein family. Sorcin is highly expressed in many tissues, including bone, heart, brain, lung, and skin tissues. Single-cell RNA sequencing showed that sorcin was expressed in the outer HCs of mice, but its role remained unknown. We also found that sorcin was highly expressed in the cytoplasm of cochlear HCs and HEI-OC1 cells. After cisplatin injury, the expression of sorcin in HCs and HEI-OC1 cells decreased significantly. SiRNA transfection technology was used to knock down the expression of sorcin. The results showed that the number of apoptotic cells, the expression of cleaved caspased-3, and the expression of Bax increased while the anti-apoptotic factor Bcl-2 decreased in the siRNA-Sorcin + CIS group. The observed increase in apoptosis was related to the increase of reactive oxygen species (ROS) and the destruction of the mitochondrial membrane potential (MMP). Finally, we found that the downregulated sorcin worked by activating the P-ERK1/2 signaling pathway. Overall, this study showed that sorcin can be used as a new target to prevent the ototoxicity of platinum drugs.

The Role of RNA Modifications and RNA-modifying Proteins in Cancer Therapy and Drug Resistance.

The advent of new genome-wide sequencing technologies has uncovered abnormal RNA modifications and RNA editing in a variety of human cancers. The discovery of reversible RNA N6-methyladenosine (RNA: m6A) by fat mass and obesity-associated protein (FTO) demethylase has led to exponential publications on the pathophysiological functions of m6A and its corresponding RNA modifying proteins (RMPs) in the past decade. Some excellent reviews have summarized the recent progress in this field. Compared to the extent of research into RNA: m6A and DNA 5-methylcytosine (DNA: m5C), much less is known about other RNA modifications and their associated RMPs, such as the role of RNA: m5C and its RNA cytosine methyltransferases (RCMTs) in cancer therapy and drug resistance. In this review, we will summarize the recent progress surrounding the function, intramolecular distribution and subcellular localization of several major RNA modifications, including 5' cap N7-methylguanosine (m7G) and 2'-O-methylation (Nm), m6A, m5C, A-to-I editing, and the associated RMPs. We will then discuss dysregulation of those RNA modifications and RMPs in cancer and their role in cancer therapy and drug resistance.