Screening and cloning of multi-drug resistant genes in HL-60/MDR cells

All-trans retinoic acid in anticancer therapy: how nanotechnology can enhance its efficacy and resolve its drawbacks

Introduction: All-trans retinoic acid (ATRA, tretinoin) is the main drug used in the treatment of acute promyelocytic leukemia (APL). Despite its impressive activity against APL, the same could not be clinically observed in other types of cancer. Nanotechnology can be a tool to enhance ATRA anticancer efficacy and resolve its drawbacks in APL as well as in other malignancies.Areas covered: This review covers ATRA use in APL and non-APL cancers, the problems that were found in ATRA therapy and how nanoencapsulation can aid to circumvent them. Pre-clinical results obtained with nanoencapsulated ATRA are shown as well as the two ATRA products based on nanotechnology that were clinically tested: ATRA-IV® and Apealea®.Expert opinion: ATRA presents interesting properties to be used in anticancer therapy with a notorious differentiation and antimetastatic activity. Bioavailability and resistance limitations impair the use of ATRA in non-APL cancers. Nanotechnology can circumvent these issues and provide tools to enhance its anticancer activities, such as co-loading of multiple drug and active targeting to tumor site.

PLCB4 upregulation is associated with unfavorable prognosis in pediatric acute myeloid leukemia

Phospholipase C (PLC) is a membrane-associated enzyme that regulates several cellular behaviors including cell motility, growth, transformation and differentiation. PLC is involved in cancer migration, invasion and drug resistance. However, the expression status and prognostic role of PLCB4 in acute myeloid leukemia (AML) remain unclear. In the present study, the complete clinical and mRNA expression data of 285 pediatric patients with de novo AML were obtained from the Therapeutically Available Research to Generate Effective Treatments database. The association between PLCB4 expression and clinical and molecular features was explored. The expression of PLCB4 was significantly higher in patients with AML who relapsed compared with those with long-term complete remission. Patients with PLCB4 upregulation had significantly lower overall survival (OS) and event free survival (EFS) rate compared with those with low PLCB4 expression. Multivariate Cox's regression analyses demonstrated that high PLCB4 expression was an independent risk factor of adverse OS (P<0.01; HR, 2.081) and EFS (P<0.01; HR, 2.130). Following stratification analysis according to transplant status in cases of first complete remission, the patients with high expression of PLCB4 had significantly lower OS and EFS rate in the chemotherapy group, but not the stem cell transplant group. Furthermore, PLCB4-associated genes were identified using Spearman's rank correlation analysis. KEGG pathway analysis revealed that PLCB4 and its associated genes were mainly involved in three potential pathways, including the Rap1 signaling pathway. Overall, the findings of the present study suggest that increased PLCB4 expression is associated with poor clinical outcome in pediatric patients with AML, and thus may represent a potential prognostic biomarker and therapeutic target for AML.

Potential association of long noncoding RNA HA117 with tetralogy of Fallot

Tetralogy of Fallot (TOF) is a congenital heart disease characterized by abnormal cardiomyocyte differentiation in the right ventricular outflow tract (RVOT), and HA117 is a novel long noncoding RNA (lncRNA) with anti-differentiation roles. To investigate the potential association of HA117 with TOF, we collected 84 RVOT tissues from patients with TOF. We determined the expression of HA117 in RVOT samples from TOF patients and collected clinical data to conduct a cross-sectional and short-term follow-up study. McGoon ratio, Nakata index, and left ventricular end-diastolic volume index (LVEDVI) were negatively correlated with the expression of HA117 based on subgroup analysis, correlation analysis and logistic regression analysis. Additionally, cardiopulmonary bypass (CPB) time and ICU stay were longer in patients with higher expression of HA117 than in patients with lower expression of HA117. Furthermore, percentage improvement in SPO₂ was significantly reduced in patients with increased HA117 expression at 6 months after surgery. Our results suggested that the increased expression of the novel lncRNA HA117 is a risk factor for unfavorable McGoon ratio, Nakata index and LVEDVI in TOF patients. Additionally, an increased expression of HA117 might lead to adverse short-term outcomes in TOF patients.

RNA Sequencing Uncovers Molecular Mechanisms Underlying Pathological Complete Response to Chemotherapy in Patients with Operable Breast Cancer

Background

This study aimed to identify key genes contributing to pathological complete response (pCR) to chemotherapy by mRNA sequencing (RNA-seq).

Material/Methods

RNA was extracted from the frozen biopsy tissue of patients with pathological complete response and patients with non-pathological complete response. Sequencing was performed on the HiSeq2000 platform. Differentially expressed genes (DEGs) were identified between the pCR group and non-pCR (NpCR) group. Pathway enrichment analysis of DEGs was performed. A protein-protein interaction network was constructed, then module analysis was performed to identify a subnetwork. Finally, transcription factors were predicted.

Results

A total of 673 DEGs were identified, including 419 upregulated ones and 254 downregulated ones. The PPI network constructed consisted of 276 proteins forming 471 PPI pairs, and a subnetwork containing 18 protein nodes was obtained. Pathway enrichment analysis revealed that PLCB4 and ADCY6 were enriched in pathways renin secretion, gastric acid secretion, gap junction, inflammatory mediator regulation of TRP channels, retrograde endocannabinoid signaling, melanogenesis, cGMP-PKG signaling pathway, calcium signaling pathway, chemokine signaling pathway, cAMP signaling pathway, and rap1 signaling pathway. CNR1 was enriched in the neuroactive ligand-receptor interaction pathway, retrograde endocannabinoid signaling pathway, and rap1 signaling pathway. The transcription factor-gene network consists of 15 transcription factors and 16 targeted genes, of which 5 were downregulated and 10 were upregulated.

Conclusions

We found key genes that may contribute to pCR to chemotherapy, such as PLCB4, ADCY6, and CNR1, as well as some transcription factors.

HA117 endows HL60 cells with a stem-like signature by inhibiting the degradation of DNMT1 via its ability to down-regulate expression of the GGL domain of RGS6

All-trans retinoic acid (ATRA) induces complete remission in almost all patients with acute promyelocytic leukemia (APL) via its ability to induce the in vivo differentiation of APL blasts. However, prolonged ATRA treatment can result in drug resistance. In previous studies, we generated a multi-drug-resistant HL60/ATRA cell line and found it to contain a new drug resistance-related gene segment, HA117. In this study, we demonstrate that ATRA induces multi-drug-resistant subpopulations of HL60 cells with a putative stem-like signature by up-regulating the expression of the new gene segment HA117. Western blot analysis and quantitative real-time PCR demonstrated that HA117 causes alternative splicing of regulator of G-protein signaling 6 (RGS6) and down-regulation of the expression of the GGL domain of RGS6, which plays an important role in DNA methyltransferase 1 (DNMT1) degradation. Moreover, DNMT1 expression was increased in multi-drug resistance HL60/ATRA cells. Knockdown of HA117 restored expression of the GGL domain and blocked DNMT1 expression. Moreover, resistant cells displayed a putative stem-like signature with increased expression of cancer steam cell markers CD133 and CD123. The stem cell marker, Nanog, was significantly up-regulated. In conclusion, our study shows that HA117 potentially promotes the stem-like signature of the HL60/ATRA cell line by inhibiting by the ubiquitination and degradation of DNMT1 and by down-regulating the expression of the GGL domain of RGS6. These results throw light on the cellular events associated with the ATRA-induced multi-drug resistance phenotype in acute leukemia.

Screening siRNAs targeting a novel gene (HA117) and the development of a derivative recombinant adenovirus delivery system

A novel gene, HA117, was discovered in our previous work. Using the pSOS-HUS vector method which we designed at previous study, we screened for small interfering RNAs (siRNAs) that targeted HA117. The pSOS-HUS siRNA screening results were verified and a delivery system was developed that contained a recombinant adenovirus carrying DNA templates for the transcription of the HA117 siRNAs. Of five pairs of DNA templates, siRNA transcribed from HAi5 produced the strongest effect against HA117. A recombinant adenovirus containing HAi5 (Ad-HAi5) was successfully constructed and evaluated. This work has laid the foundation for further study of HA117 gene function using RNA interference technology and has showed the pSOS-HUS vector method was successfully utilized as a rapid and effective screen of siRNAs for a target gene.

Construction, screening and evaluation of a derivative recombinant adenovirus for the optimal siRNA targeting of a novel gene (HA117)

At this study, we screened for an optimal siRNA to target a novel gene named HA117 and constructed and evaluated a recombinant adenovirus carrying the DNA template for the transcription of the optimal HA117 siRNA to examine the function of HA117 and its possible mechanism of action in CW-2 cell lines. An HAi5-carrying recombinant adenovirus (Ad-HAi5) was successfully constructed and evaluated. The results show that, among five pairs of DNA templates, siRNA transcribed from HAi5 gave the strongest interference with the novel gene HA117. The expression of the exogenous HA117 gene increased drug resistance in CW-2 cells. We hypothesized that this action may be a result of HA117 through inhibiting apoptosis in CW-2 cells.

Functional study of the novel multidrug resistance gene HA117 and its comparison to multidrug resistance gene 1

BACKGROUND

The novel gene HA117 is a multidrug resistance (MDR) gene expressed by all-trans retinoic acid-resistant HL-60 cells. In the present study, we compared the multidrug resistance of the HA117 with that of the classical multidrug resistance gene 1 (MDR1) in breast cancer cell line 4T1.

METHODS

Transduction of the breast cancer cell line 4T1 with adenoviral vectors encoding the HA117 gene and the green fluorescence protein gene (GFP) (Ad-GFP-HA117), the MDR1 and GFP (Ad-GFP-MDR1) or GFP (Ad-GFP) was respectively carried out. The transduction efficiency and the multiplicity of infection (MOI) were detected by fluorescence microscope and flow cytometry. The transcription of HA117 gene and MDR1 gene were detected by reverse transcription polymerase chain reaction (RT-PCR). Western blotting analysis was used to detect the expression of P-glycoprotein (P-gp) but the expression of HA117 could not be analyzed as it is a novel gene and its antibody has not yet been synthesized. The drug-excretion activity of HA117 and MDR1 were determined by daunorubicin (DNR) efflux assay. The drug sensitivities of 4T1/HA117 and 4T1/MDR1 to chemotherapeutic agents were detected by Methyl-Thiazolyl-Tetrazolium (MTT) assay.

RESULTS

The transducted efficiency of Ad-GFP-HA117 and Ad-GFP-MDR1 were 75%-80% when MOI was equal to 50. The transduction of Ad-GFP-HA117 and Ad-GFP-MDR1 could increase the expression of HA117 and MDR1. The drug resistance index to Adriamycin (ADM), vincristine (VCR), paclitaxel (Taxol) and bleomycin (BLM) increased to19.8050, 9.0663, 9.7245, 3.5650 respectively for 4T1/HA117 and 24.2236, 11.0480, 11.3741, 0.9630 respectively for 4T1/MDR1 as compared to the control cells. There were no significant differences in drug sensitivity between 4T1/HA117 and 4T1/MDR1 for the P-gp substrates (ADM, VCR and Taxol) (P < 0.05), while the difference between them for P-gp non-substrate (BLM) was statistically significant (P < 0.05). DNR efflux assay confirmed that the multidrug resistance mechanism of HA117 might not be similar to that of MDR1.

CONCLUSIONS

These results confirm that HA117 is a strong MDR gene in both HL-60 and 4T1 cells. Furthermore, our results indicate that the MDR mechanism of the HA117 gene may not be similar to that of MDR1.

Multidrug resistance strength of the novel multidrug resistance gene HA117: compared with MRP1

The novel gene HA117 is a multidrug resistance (MDR) gene in all-trans retinoic acid resistance HL-60 cells. The transduction of adenovirus vectors encoding HA117 conferred breast cancer cell line 4T1 MDR not only to MRP1 substrate drugs but also to MRP1 non-substrate drugs and the MDR strength of HA117 was similar to that of multidrug resistance-associated protein-1 (MRP1) for MRP1 substrate, but HA117 had no daunorubicin-excretion function.

HA117 gene increased the multidrug resistance of K562 cells in vitro: an investigation to the function of a novel gene related to drug resistance

OBJECTIVE

A novel multi-drug resistance gene named as HA117 has been screened and cloned in multidrug resisitant leukemia cell lines in our previous research, but its function is still unknown. In this study, HA117 gene was investigated whether it could increase the drug resistance in chronic myelogenous myeloid leukemia cell line K562.

METHODS

HA117 was cloned and adenovirus vectors were constructed with the HA117 gene (Adeasy-HA117). K562 cells were infected by Ad-HA117 to get the K562/Ad-HA117 cells with HA117 gene expression. The infection efficiency and the multiplicity of infection (MOI) were detected by fluorescence and flow cytometry. The expression of HA117 gene was detected by RT-PCR. The drug sensitivities of K562/Ad-HA117 cells were detected by Methyl Thiazolyl Tetrazolium (MTT) assay.

RESULTS

Recombinant adenovirus vectors were constructed and a MOI of 100 is most suitable to infect K562 cells. The infected K562 cells demonstrated in vitro production of HA117 mRNA as measured by reverse-transcriptase polymerase chain reaction. There were no significant changes in K562/Ad-HA117 cells growth, while the drug sensitivities of K562/Ad-HA117 cells to Vincristine, Adriamycin, Etoposide, Daunorubicin, Mitomycin and Cyclophosphamide decreased 4.44, 7.18, 3.01, 9.53, 3.48 and 3.61 times than that of uninfected K562 cells, respectively (P < 0.05).

CONCLUSION

Expression of the novel gene HA117 could significantly increased the multi-drug resistance of K562 cells, which indicated that HA117 is a functionally relevant multidrug resistance gene.