Drug Resistance, Neoplasm ; Humans ; Multiple Myeloma

The study was aimed to investigate the effect of quercetin, flavonoid molecules on reversing leukemia multidrug resistance and its mechanism. K562/A cells were cultured in vitro with different concentrations of quercetin. Cell growth inhibition and adriamycin (ADR) sensitivity were detected by MTT method. Intracellular ADR concentration was determined by flow cytometry. Cell apoptosis was assayed by Annexin V/PI staining method. The expressions of drug transporter and apoptosis related genes were measured by real-time PCR array. The results indicated that quercetin inhibited the proliferation of K562 and K562/A in 5-160 µmol/L and with dose-dependent manner. Quercetin increased the sensitivity of K562/A cells to ADR in a low toxicity concentration. Flow cytometry showed that the quercetin increased the accumulation of ADR in K562/A cells when cells were co-cultured with 5 µmol/L ADR for 2 hours. Quercetin could induce the apoptosis of K562 and K562/A cells with dose dependent manner. Furthermore, some drug transport related genes such as ATP-binding cassette (ABC) and solute carrier (SLC) and some apoptosis-related genes such as BCL-2, tumor necrosis factor (TNF), tumor necrosis factor receptor (TNFR) families were down-regulated by quercetin. It is concluded that quercetin reverses MDR of leukemic cells by multiple mechanisms and the reversing effect is positively related to drug concentration.
Drug Resistance, Multiple ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Humans ; K562 Cells ; Quercetin ; pharmacology

Major progress in the management of osteosarcoma has been made due to advances in diagnostic imaging, operative technique, and chemotherapy, resulting in an improved survival. However, 20~30% of patients with osteosarcoma still develop distant metastases despite combined modality treatment. Currently various experimental efforts are being proposed to the future new strategy include drug resistance, suppression of metastasis mechanism, and targeted therapy to convert the incurable rate of 20~30% upto complete cure rate.
Diagnostic Imaging ; Drug Resistance ; Drug Therapy ; Humans ; Neoplasm Metastasis ; Osteosarcoma*

Drug Resistance, Neoplasm ; Humans ; Stomach Neoplasms ; drug therapy

Drug therapy is one of the efficient methods for prostate cancer treatment. However, drug resistance greatly hindered the treatment of prostate cancer patients. Herein, the mechanisms of drug resistance in prostate cancer have been exhaustively reviewed, and that can provide an alternative strategy and new targets for anti-prostate cancer therapy.
Drug Resistance, Neoplasm ; Humans ; Male ; Prostatic Neoplasms ; drug therapy

Non-Hodgkin's lymphoma (NHL) is a malignant tumor originated in lymphatic hematopoietic tissue. At present, chemotherapy is the main treatment method of NHL, but the chemoresistance is still an important reason for NHL treatment failure. The mechanism of NHL multidrug resistance (MDR) is complex, involving a variety of singnal pathways, in which mutation in the genetic level of the key genes can result in tumor cell resistance phenomenon. MicroRNA are small non-coding RNA that can be widely detected in plants,animal species and viruses. They regulate protein expression by repressing translation mRNA target at the post-transcriptional level, participating in the differentiation and development of tumor cells, as well as the occurrence and development of tumor, the change of the expression level microRNA plays an important role in the genesis and chemoresistance mechanism of NHL. Therefore, the intervening factitiously the expression level of microRNA in NHL through manufacturing antisense oligonucleotide (AMO) or using substitution of microRNA, changing the expression level of their target protein, and combining with the therapy of NHL, there will be an guiding significance in reversing the drug and radiation resistance of NHL, thus improving its poor prognosis. This article reviews the microRNAs closely related with drug and radiation resistance of NHL, and their potential targets. Furthermore, the specific role of these microRNAs in the genesis and chemoresistance mechanism of NHL are deeply elaborated.
Animals ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Lymphoma, Non-Hodgkin ; drug therapy ; genetics ; MicroRNAs ; genetics

Gastric cancer is one of the most common human malignancies and the third cause of death from cancer in China and worldwide. Chemotherapy is still one of the major treatment options for advanced gastric cancer. However,the efficacy of chemotherapy for gastric cancer remains poor due to its insensitivity and the development of multidrug resistance (MDR). While many molecules and mechanisms have been found to be associated with the development of gastric cancer MDR,the specific mechanisms remains unclear. In our current article,we reviews the identification of MDR-related molecules and mechanisms,with an attempt to a better understand the specific mechanisms of gastric cancer MDR and thus provide new insights into the fight against gastric cancer MDR.
Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Humans ; Stomach Neoplasms ; drug therapy

OBJECTIVE: To investigate the effect of Bmi-1 gene silencing on drug resistance of leukemia cell K562/ADR and to explore its possible mechanism. METHODS: After two sequences of Bmi-1-siRNA were transfected into drug-resistant K562/ADR cells, the mRNA and protein expressions of Bmi-1 gene were detected. After Bmi-1 gene silencing the expression of P-gp and MDR1 were detected and the accumulation of doxorubicin in K562/ADR cells were detected by flow cytometry to determine the effect of Bmi-1 gene silencing on drug resistance of K562/ADR cells. The protein expression of NF-κB was analyzed after Bmi-1 gene silencing. Then after K562/ADR cells were treated with NF-κB inhibitor PDTC, the protein expression of P-gp and its functional changes were analyzed to determine the effect of NF-κB on drug resistance of leukemia cells. The protein expressions of PTEN, AKT and p-AKT after Bmi-1 gene silencing were detected and the effect of Bmi-1 gene silencing on PTEN/PI3K/AKT signaling pathway in drug-resistant cells was determined. After K562/ADR cells were treated with PI3K/AKT pathway inhibitor LY294002, the protein expressions of NF-κB and P-gp were analyzed to determine the regulation of AKT on the expression of NF-κB and P-gp. The protein expressions of AKT, p-AKT, NF-κB and P-gp were detected after the Bmi-1-siRNA transfected cells were treated by PTEN inhibitor BPV. Above-mentioned expression of mRNA was detected by RT-PCR, and the protein expression was detected by Western blot. RESULTS: The expression of Bmi-1 gene in K562/ADR cells decreased at both mRNA and protein levels and the doxorubicin accumulation increased after Bmi-1 gene silencing. The expression of MDR1/P-gp in Bmi-1-siRNA transfected cells was lower than that in K562/ADR cells (P＜0.05). After Bmi-1 gene silencing, the activity of NF-κB decreased. The activity of NF-κB and P-gp expression was inhibited and the function of P-gp in K562/ADR cells was reduced by using NF-κB inhibitor (PDTC). The protein expression of PTEN increased while the protein expression of p-AKT decreased after Bmi-1 gene silencing (P＜0.05). The protein expressions of p-AKT, P-gp and the activity of NF-κB were inhibited significantly by using PI3K/AKT inhibitor LY294002 (P＜0.05). After the Bmi-1-siRNA transfected cells were treated by PTEN inhibitor BPV, the activity of NF-κB and the protein expressions of P-gp were restored. CONCLUSION Bmi-1 plays a key role in MDR-mediated multidrug resistance in K562/ADR cells, which may be mediated by activating PTEN/AKT pathway to regulate NF-κB.
Doxorubicin ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Humans ; K562 Cells ; Mitogen-Activated Protein Kinase 7

OBJECTIVE: To explore the reversal effect of pioglitazone (PIO) on multidrug resistance in K562/ADR cells and its mechanism. METHODS: The proliferation inhibition rate, half inhibition concentration (IC) and drug-resistance reversal multipe were detected and the curve of proliferation inhibition rate was drawn by MTT assay, the transcription of PPARγ, CYP2C8 and CYP2J2 genes was detected by RT-PCR; the expression of PPARγ, CYP2C8 and CYP2J2 proteins was detected by Western blot. RESULTS: The IC of PIO on K562 and K562/ADR cells for 60 h was 326.7 μmol/L and 349.1 μmol/L respectively. The reversal multiple of 30 μmol/L PIO on ADR-resistance of K562/ADR cells was 6.4. After treatment of K562/ADR cells with PIO, the transcription of CYP2C8 and CYP2J2 and the protein expression of CYP2C8 and CYP2J2 significantly decreased, the transcription of PPARγ gene and the expression of PPARγ protein were not changed. CONCLUSIONS Pioglitazone can reverse the adriamycin-resistance in K562/ADR cells that is closely related to the decrease of protein expression of CYP2C8 and CYP2J2. Pioglitazone is an effective multidrug resistance reversal agent for tumors.
Doxorubicin ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Humans ; K562 Cells ; Pioglitazone

OBJECTIVE: To explore the effect of Bushen Yanggu Decoction (BYD) on drug resistance and proliferation of human multiple myeloma-resistant KM3/BTZ cells. METHODS: Human multidrug-resistant KM3/BTZ cells were established by Bortezomib (BTZ) gradient induction. The effects of commonly used chemotherapeutic drugs and serum containing Bushen Yanggu Decoction (BYD) on the proliferation of KM3 cells and KM3/BTZ cells were detected by MTT assay. RT-qPCR and Western blot were used to detect the expression of Par-4, HSP27 and P-gp genes. Flow cytometry was used to detect cell apoptosis. RESULTS: The established KM3/BTZ cells could produce varying degree of resistance to commonly used chemotherapeutic drugs. Among them, the highest resistance index (RI) to BTZ was 20.269. MTT assay showed that the proliferation of KM3/BTZ cells treated with serum containing Bushen Yanggu Decoction was inhibited, and the inhibitory effect increased with the serum concentration incranse of Bushen Yanggu Decoction. The serum containing Bushen Yanggu Decoction could inhibit the proliferation of KM3/BTZ cells, and induce apoptosis, significantly reduce the drug-resistance of KM3/BTZ cells, up-regulate the expression of Par-4, down-regulate the expression of HSP27 and P-gp. CONCLUSION Bushen Yanggu Decoction can effectively inhibit the proliferation of KM3/BTZ cells and induce apoptosis. Bushen Yanggu Decoction can effectively reverse the multidrug-resistance of KM3/BTZ cells. The mechanism may be related with the decrease of expression of HSP27 and P-gp and the increase of expression of Par-4.
Apoptosis ; Bortezomib ; Cell Line, Tumor ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Humans ; Multiple Myeloma