Adenosine A2A receptor activation regulates the M1 macrophages activation to initiate innate and adaptive immunity in psoriasis.

Psoriasis is a common inflammatory systemic disease characterized by pro-inflammatory macrophages activation (M1 macrophage) infiltrated in the dermal layer. How M1 macrophage contributes to psoriasis remains unknown. In this study, we found that adenosine A2A receptor (A2AR) agonist CGS 21680 HCl alleviated the imiquimod (IMQ) and mouse IL-23 Protein (rmIL-23)-induced psoriasis inflammation through reducing infiltration of M1. Conversely, Adora2a deletion in mice exacerbated psoriasis-like phenotype. Mechanistically, A2AR activation inhibited M1 macrophage activation via the NF-κB-KRT16 pathway to reduce the secretion of CXCL10/11 and inhibit Th1/17 differentiation. Notably, the KRT16 expression was first found in M1 macrophage in our study, not only in keratinocytes (KCs). CXCL10/11 are first identified as primarily derived from macrophages and dendritic cells (DCs) rather than KCs in psoriasis using single cell RNA sequencing (scRNA-Seq). In total, the study emphasizes the importance of M1 as an innate immune cell in pathogenesis of psoriasis.

Evaluation of the inflammatory parameters as potential biomarkers of systemic inflammation extent and the disease severity in psoriasis patients.

The disease severity of psoriasis is mainly assessed subjectively via  psoriasis area and severity index (PASI) and body surface area (BSA), while an optimal measure of cutaneous response, may overlook systemic inflammation in psoriasis patients. The neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), monocyte to lymphocyte ratio (MLR), monocyte to high density lipoprotein ratio (MHR), and systemic immune-inflammation index (SII) exhibit notable associations with the inflammation severity in multiple diseases. The aim of this retrospective study was to explore the associations between inflammatory parameters and the skin lesions' severity of psoriasis. After analysis, we found that patients with psoriasis had higher NLR, MLR, PLR, MHR, and SII levels compared to the control group. At baseline, the parameters of NLR (r = 0.124, P = 0.003), MLR (r = 0.153, P < 0.001), MHR (r = 0.217, P < 0.001) and SII (r = 0.141, P = 0.001) had a positive correlation with PASI in psoriasis patients. At the same time, we analyzed the patients who received different systemic therapy. We observed a significant decrease in NLR, PLR, MLR, and SII in psoriasis patients after treatment. Notably, TNF-α inhibitors and IL-17A inhibitors subgroups showed a more significant reduction than IL-23/IL-12/23 inhibitors and MTX medication. Additionally, we found the change of NLR (r = 0.194, P < 0.001), PLR (r = 0.104, P = 0.014), MLR (r = 0.191, P < 0.001), MHR (r = 0.106, P = 0.012), and SII (r = 0.228, P < 0.001) had a positive correlation with the change of PASI in psoriasis patients. In conclusion, this study suggests that NLR, MLR, and SII may serve as useful biomarkers for assessing systemic inflammation extent and disease severity in psoriasis patients.

Expert Consensus on the Application of Stem Cells in Psoriasis Research and Clinical Trials.

Psoriasis is an immune-mediated, chronic, relapsing, inflammatory, systemic disease induced by individual-environmental interactions, and is often lifelong because of the difficulty of treatment. In recent years, a variety of targeted therapies, including biologics, have improved the lesions and quality of life of most psoriasis patients, but they still do not address the problem of relapse and may be associated with decreased efficacy or adverse events such as infections over time. Therefore, there is an urgent need for breakthroughs in psoriasis treatment and in relapse-delaying and non-pharmacologic strategies, and stem cell therapy for psoriasis has emerged. In recent years, research on stem cell therapy for psoriasis has received a lot of attention, however, there is no reference standard as well as consensus in this field of research. Therefore, according to the latest consensus and guidelines, combined with relevant literature reports, clinical practice experience and the results of discussions with experts, this consensus specifies the types of stem cells commonly used in the treatment of psoriasis, the methods, dosages, and routes of stem cell therapy for psoriasis, as well as the clinical evaluations (efficacy and safety) of stem cell therapy for psoriasis. In addition, this consensus also provides normative standards for the processes of collection, preparation, preservation and quality control of stem cells and their related products, as well as recommendations for the management of stem cells during infusion for the treatment of psoriasis. This consensus provides the latest specific reference standards and practice guidelines for the field of stem cell therapy for psoriasis.

A miRNA-492 binding-site polymorphism in BSG (basigin) confers risk to psoriasis in central south Chinese population.

Psoriasis (PS; MIM#177900) is a chronic inflammatory immune-mediated skin disorder. Although the disease is believed to be caused by a combination of genetic, immunologic and environmental factors, its complete etiology has not been fully understood. Here, we focused on the BSG (MIM#109480), a member of the immunoglobulin superfamily expressed ubiquitously in circulating immune cell populations. We observed that the expression level of BSG in PBMCs was elevated in psoriasis patients. To understand the underlying mechanism for this change, we genotyped the rs8259 T>A SNP located in the 3'UTR of the BSG gene from 668 psoriasis patients and 1,143 healthy controls. The rs8259 T allele was associated with significantly decreased psoriasis susceptibility (OR = 0.758, 95% CI 0.638-0.901, p = 0.002). Interestingly, the rs8259 polymorphism was located in a seed region for miR-492 binding. The miR-492 was able to bind to the BSG 3'UTR sequence bearing the rs8259 T allele as assayed by luciferase reporter gene assay. The substitution of T with A abolished miR-492 binding. BSG protein expression in PBMCs from patients carrying the rs8259 AA genotype was significantly higher than in those from patients carrying the rs8259 TT genotype. Our study suggests that miR-492 may physiologically suppress BSG expression and the BSG rs8259 polymorphism is associated with decreased psoriasis susceptibility through affecting miR-492 binding.

Inhibition of c-Kit, VEGFR-2 (KDR), and ABCG2 by analogues of OSI-930.

The quinoline domain of OSI-930, a dual inhibitor of receptor tyrosine kinases (RTKs) c-Kit and KDR, was modified in an effort to further understand the SAR of OSI-930, and the binding site characteristics of c-Kit and KDR. A series of 16 compounds with heteroatom substituted pyridyl and phenyl ring systems was synthesized and evaluated against a panel of kinases including c-Kit and KDR. Aminopyridyl derivative 6 was found to be the most active member of the series with 91% and 57% inhibition of c-Kit at 10µM and 1µM, respectively and 88% and 50% inhibition of KDR at 10µM and 1µM, respectively. The target compounds were also tested for their ability to inhibit efflux of mitoxantrone through inhibition of ATP dependent ABCG2 pump. Nitropyridyl derivative 5 and o-nitrophenyl derivative 7 exhibited complete inhibition of the ABCG2 pump with IC(50) values of 13.67µM and 16.67µM, respectively.

Polyethylene Glycol Ointment Alleviates Psoriasis-Like Inflammation Through Down-Regulating the Function of Th17 Cells and MDSCs.

Objective: To explore the possible mechanism of improving the imiquimod (IMQ)-induced psoriasis-like inflammation by using polyethylene glycol (PEG) ointment. Methods: We evaluated the appearance of psoriasis lesions by Psoriasis Area and Severity Index (PASI), observed the epidermal proliferation by histopathological staining and immunohistochemical staining, and explored the key molecules and signaling pathways of improving psoriasis-like inflammation treated with PEG ointment by RNA sequencing. Finally, we verified the expression of inflammatory cells and inflammatory factors by flow cytometry, immunohistochemical staining, and Q-PCR. Results: PEG ointment could improve the appearance of psoriasis lesions and the epidermis thickness of psoriasis mouse, inhibit the proliferation of keratinocytes, and down-regulate the relative mRNA levels of IL-23, IL-22, IL-6, IL-17C, IL-17F, S100A7, S100A8, S100A9, CXCL1, CXCL2, and IL-1ß in the skin lesions of psoriasis mouse by down-regulating the numbers of myeloid-derived suppressor cells (MDSCs) and T helper 17 (Th17) cells. Conclusion: PEG ointment could improve the IMQ-induced psoriasis-like inflammation by down-regulating the functions of Th17 cells and MDSCs.

Sipholane triterpenoids: chemistry, reversal of ABCB1/P-glycoprotein-mediated multidrug resistance, and pharmacophore modeling.

This study reports the isolation of nine new terpenoids (2-10), possessing two novel skeletons, from the Red Sea sponge Callyspongia (=Siphonochalina) siphonella. The identity of these novel skeletons was based on X-ray crystallography and extensive spectral analyses. These compounds were evaluated for their ability to reverse P-glycoprotein (P-gp)-mediated multidrug resistance in human epidermoid cancer cells. Sipholenone E (3) was better than sipholenol A (1), a known P-gp modulator from this sponge, in reversing the P-gp-mediated multidrug resistance. Sipholenol L (6) and siphonellinol D (8) were nearly as active as sipholenol A. On the basis of X-ray crystallographic data and the established identity of 3-7, the structure of sipholenol I (11) is revised. A pharmacophore model of three hydrophobic points and two H-bond acceptors was generated for the active sipholane P-gp modulators.

Genetic polymorphism predicting Methotrexate efficacy in Chinese patients with psoriasis vulgaris.

BACKGROUND: Methotrexate is the first systemic therapeutics of psoriasis. It is reported that 40% of the patients achieved a PASI75 after 12 weeks with a small dose of methotrexate (15mg / w) treatment. So far there is not any large-scale exome sequencing been used to predict the efficacy of methotrexate in the treatment of psoriasis vulgaris. OBJECTIVE: To analyze the genetic polymorphism to predict methotrexate efficacy in Chinese patients with psoriasis vulgaris. METHODS: In this study, we used the whole exon high-throughput sequencing technology to detect the DNA sequence of 22 psoriasis vulgaris patients (11 responders, 11 non-responders) treated with methotrexate and captured approximately 236 variants with statistically significant in the whole exon sequencing, then in accordance with statistical differences and clinical relevance, we further selected 36 SNPs and 14 SNPs that have been reported in articles associated with the response of methotrexate. We used MassARRAY method to verify the 50 SNPs in 100 psoriatic patients treated with methotrexate. RESULTS: We found 3 SNPs, rs216195T>C in SMG6, rs1050301G>A in IMMT, rs2285421T>C in UPK1A which might associate with the drug response of methotrexate. CONCLUSION: We have searched 3 new SNPs that could predict the efficacy of methotrexate in psoriasis vulgaris to some extent, providing a theoretical basis for precision medicine of methotrexate in future.

Inhibition of CD147 gene expression via RNA interference reduces tumor cell proliferation, activation, adhesion, and migration activity in the human Jurkat T-lymphoma cell line.

CD147, a leukocyte surface molecule over-expressed in T-lymphoma cells, is reportedly associated with lymphocyte activation and proteinase production via interactions with fibroblasts and plays a role in stromal invasion by lymphoma cells. To determine the role of CD147 in the progression of T-lymphoma, we performed siRNA interference-mediated knockdown of CD147 in a CD147-expressing Jurkat T-cell line. CD147 knockdown resulted in the decreased proliferation and migration of Jurkat cells and reduced the adhesion of Jurkat cells to extracelluar matrix fibronectin in vitro. CD147-siRNA inhibited the activation of Jurkat cells via down-regulation of CD25 expression. Our results indicate that CD147 is involved in T-lymphoma progression, a finding useful in efforts to develop targeted therapies to treat patients with T-lymphoma.

Topical Sunitinib ointment alleviates Psoriasis-like inflammation by inhibiting the proliferation and apoptosis of keratinocytes.

Psoriasis is a chronic auto-immune inflammation disease with skin lesions and abnormal keratinocyte proliferation. Sunitinib, a multi-targeted tyrosine kinase inhibitor, is known to selectively inhibit several growth factor receptors, including vascular endothelial growth factor receptor, platelet-derived growth factor receptor and stem cell factor. It was reported that a patient with renal cell carcinoma (RCC) whose psoriatic lesion was resolved dramatically during treatment with Sunitinib, however, the mechanism is still unclear. We applied Sunitinib ointment to treat imiquimod-induced mouse model of psoriasis and found that Sunitinib ointment could alleviate imiquimod-induced psoriasis-like inflammation and reduce the Ki67 expression, while Sunitinib ointment couldn't reduce imiquimod-induced splenomegaly of the mouse model, then we concentrated on studying the effect of Sunitinib on the proliferation and apoptosis of keratinocytes, we cultivated HaCaT cells with epidermal growth factor (HaCaT/E cells) to represent as a state of highly proliferative psoriatic keratinocytes. We found that Sunitinib could inhibit the proliferation of Hacat/E cell in a time and concentration dependent manner by influencing the expression level of cell cycle protein D1, cycle protein E1, in addition, Sunitinib could induce the apoptosis of Hacat/E cell and up-regulate the expression of poly ADP-ribose polymerase (PARP). Sunitinib down-regulated the expression of phosphorylated signal transduction and activator of transcription 3 (p-Stat3) of Hacat/E cells significantly. We conclude that Sunitinib alleviates imiquimod-induced psoriasis-like inflammation by regulating the proliferation and apoptosis of HaCaT cells through inhibiting the expression of p-Stat3.

[Effect of pSUPER/CD147siRNA on the growth of malignant melanoma in nude mice].

OBJECTIVE: To investigate the effect of pSUPER/CD147siRNA on the formation, proliferation, and angiogenesis of malignant melanoma in nude mice. METHODS: The nude mouse subcutaneous xenotransplantation models of malignant melanoma were constructed and observed using morphological analysis. The protein expression of PCNA and CD31 in tumors was detected using immunohistochemical technique. Tumoral proliferative activity in the nude mice was quantitatively evaluated by proliferation cell nuclear antigen (PCNA). Microvessel density( MVD) was counted based on the endothelial cells positively stained with anti-CD31 antibody. RESULTS: The subcutaneous tumors appeared in all the nude mice 5 days later after the transplantation, but the volume of malignant melanoma in the experiment group significantly decreased compared with the control group (P<0.01). PCNA expression and MVD were significantly lower in the experiment group than those in the control group ( P<0.01). CONCLUSION: CD147 siRNA inhibits the growth and angiogenesis of malignant melanoma in vivo, suggesting that CD147 might be a new gene therapy target molecule for malignant melanoma.

The association between GJB2 gene polymorphism and psoriasis: a verification study.

Psoriasis is a chronic inflammatory skin disease with multifactorial etiology. Connexin 26 (Cx26), an important gap junction protein, has been found highly expressed in plaques of psoriasis. Recently, genome wide association studies (GWAS) identified one new single nucleotide polymorphism (SNP) in GJB2 gene coding for Cx26 protein associated with psoriasis in Chinese Han population. In this paper, we verified the GWAS data in Chinese Han population. Here we genotyped the polymorphism of GJB2 rs3751385:C>T in 371 psoriasis patients and 330 healthy controls in Chinese Han population using polymerase chain reaction restriction fragment length polymorphism assay (PCR-RFLP). Our case-control assay indicated decreased frequency of the GJB2 rs3751385 C allele in psoriasis patients compared with that in the healthy controls [p = 6.02 × 10(-5), Odds ratio (OR) = 0.793, 95 % confidence interval (CI) 0.706-0.889]. The result suggested that GJB2 gene polymorphism rs3751385:C>T was associated with psoriasis susceptibility of Chinese Han population.

OSI-930 analogues as novel reversal agents for ABCG2-mediated multidrug resistance.

OSI-930, a dual c-Kit and KDR tyrosine kinase inhibitor, is reported to have undergone a Phase I dose escalation study in patients with advanced solid tumors. A series of fifteen pyridyl and phenyl analogues of OSI-930 were designed and synthesized. Extensive screening of these compounds led to the discovery that nitropyridyl and ortho-nitrophenyl analogues, VKJP1 and VKJP3, were effective in reversing ABC subfamily G member 2 (ABCG2) transporter-mediated multidrug resistance (MDR). VKJP1 and VKJP3 significantly sensitized ABCG2-expressing cells to established substrates of ABCG2 including mitoxantrone, SN-38, and doxorubicin in a concentration-dependent manner, but not to the non-ABCG2 substrate cisplatin. However, they were unable to reverse ABCB1- or ABCC1-mediated MDR indicating their selectivity for ABCG2. Western blotting analysis was performed to evaluate ABCG2 expression and it was found that neither VKJP1 nor VKJP3 significantly altered ABCG2 protein expression for up to 72 h. [(3)H]-mitoxantrone accumulation study demonstrated that VKJP1 and VKJP3 increased the intracellular accumulation of [(3)H]-mitoxantrone, a substrate of ABCG2. VKJP1 and VKJP3 also remarkably inhibited the transport of [(3)H]-methotrexate by ABCG2 membrane vesicles. Importantly, both VKJP1 and VKJP3 were efficacious in stimulating the activity of ATPase of ABCG2 and inhibited the photoaffinity labeling of this transporter by its substrate [(125)I]-iodoarylazidoprazosin. The results suggested that VKJP1 and VKJP3, specifically inhibit the function of ABCG2 through direct interaction with its substrate binding site(s). Thus VKJP1 and VKJP3 represent a new class of drugs for reducing MDR in ABCG2 over-expressing tumors.

Lapatinib and erlotinib are potent reversal agents for MRP7 (ABCC10)-mediated multidrug resistance.

In recent years, a number of TKIs (tyrosine kinase inhibitors) targeting epidermal growth factor receptor (EGFR) family have been synthesized and some have been approved for clinical treatment of cancer by the FDA. We recently reported a new pharmacological action of the 4-anilinoquinazoline derived EGFR TKIs, such as lapatinib (Tykerb) and erlotinib (Tarceva), which significantly affect the drug resistance patterns in cells expressing the multidrug resistance (MDR) phenotype. Previously, we showed that lapatinib and erlotinib could inhibit the drug efflux function of P-glycoprotein (P-gp, ABCB1) and ABCG2 transporters. In this study, we determined if these TKIs have the potential to reverse MDR due to the presence of the multidrug resistance protein 7 (MRP7, ABCC10). Our results showed that lapatinib and erlotinib dose-dependently enhanced the sensitivity of MRP7-transfected HEK293 cells to several established MRP7 substrates, specifically docetaxel, paclitaxel, vinblastine and vinorelbine, whereas there was no or a less effect on the control vector transfected HEK293 cells. [(3)H]-paclitaxel accumulation and efflux studies demonstrated that lapatinib and erlotinib increased the intracellular accumulation of [(3)H]-paclitaxel and inhibited the efflux of [(3)H]-paclitaxel from MRP7-transfected cells but not in the control cell line. Lapatinib is a more potent inhibitor of MRP7 than erlotinib. In addition, the Western blot analysis revealed that both lapatinib and erlotinib did not significantly affect MRP7 expression. We conclude that the EGFR TKIs, lapatinib and erlotinib reverse MRP7-mediated MDR through inhibition of the drug efflux function, suggesting that an EGFR TKI based combinational therapy may be applicable for chemotherapeutic practice clinically.

Nilotinib (AMN107, Tasigna) reverses multidrug resistance by inhibiting the activity of the ABCB1/Pgp and ABCG2/BCRP/MXR transporters.

Nilotinib, a BCR-Abl tyrosine kinase inhibitor (TKI), was developed to surmount resistance or intolerance to imatinib in patients with Philadelphia positive chronic myelogenous leukemia. Recently, it was shown that several human multidrug resistance (MDR) ATP-binding cassette (ABC) proteins could be modulated by specific TKIs. MDR can produce cancer chemotherapy failure, typically due to overexpression of ABC transporters, which are involved in the extrusion of therapeutic drugs. Here, we report for the first time that nilotinib potentiates the cytotoxicity of widely used therapeutic substrates of ABCG2, such as mitoxantrone, doxorubicin, and ABCB1 substrates including colchicine, vincristine, and paclitaxel. Nilotinib also significantly enhances the accumulation of paclitaxel in cell lines overexpressing ABCB1. Similarly, nilotinib significantly increases the intracellular accumulation of mitoxantrone in cells transfected with ABCG2. Furthermore, nilotinib produces a concentration-dependent inhibition of the ABCG2-mediated transport of methotrexate (MTX), as well as E(2)17betaG a physiological substrate of ABCG2. Uptake studies in membrane vesicles overexpressing ABCG2 have indicated that nilotinib inhibits ABCG2 similar to other established TKIs as well as fumitremorgin C. Nilotinib is a potent competitive inhibitor of MTX transport by ABCG2 with a K(i) value of 0.69+/-0.083 microM as demonstrated by kinetic analysis of nilotinib. Overall, our results indicate that nilotinib could reverse ABCB1- and ABCG2-mediated MDR by blocking the efflux function of these transporters. These findings may be used to guide the design of present and future clinical trials with nilotinib, elucidating potential pharmacokinetic interactions. Also, these findings may be useful in clinical practice for cancer combination therapy with nilotinib.

RNA interference targeting the CD147 induces apoptosis of multi-drug resistant cancer cells related to XIAP depletion.

CD147 (basigin, EMMPRIN) is a widely distributed cell surface glycoprotein that belongs to the Ig superfamily. It is highly expressed on the surface of malignant tumor cells to promote their invasiveness and chemo-resistance. The present study aimed to reveal the anti-apoptotic effect of CD147 on the multi-drug resistant (MDR) phenotype of human oral squamous carcinoma cells (SCC) and its possible pathways. Data presented herein showed that MDR derivative SCC KB/V cell line expressed significantly higher CD147 and X-linked inhibitor of apoptosis (XIAP) than its sensitive counterpart KB cells by RT-PCR and Western blot analysis. Down-regulation of CD147 by transfection with CD147 siRNA resulted in decreased XIAP expression. Flow cytometric analysis and electron microscopic observation revealed differential cell apoptotic status related to CD147 expression. Additionally, chemo-sensitivity to 5-fluorouracil of KB/V was increased by CD147 silencing as measured by MTT colorimetric assay. These results suggest that inhibition of CD147 and subsequent XIAP depletion may have an anti-tumor effect through enhancing the susceptibility of cancer cells to apoptosis.

Imatinib and nilotinib reverse multidrug resistance in cancer cells by inhibiting the efflux activity of the MRP7 (ABCC10).

BACKGROUND: One of the major mechanisms that could produce resistance to antineoplastic drugs in cancer cells is the ATP binding cassette (ABC) transporters. The ABC transporters can significantly decrease the intracellular concentration of antineoplastic drugs by increasing their efflux, thereby lowering the cytotoxic activity of antineoplastic drugs. One of these transporters, the multiple resistant protein 7 (MRP7, ABCC10), has recently been shown to produce resistance to antineoplastic drugs by increasing the efflux of paclitaxel. In this study, we examined the effects of BCR-Abl tyrosine kinase inhibitors imatinib, nilotinib and dasatinib on the activity and expression of MRP7 in HEK293 cells transfected with MRP7, designated HEK-MRP7-2. METHODOLOGY AND/OR PRINCIPAL FINDINGS: We report for the first time that imatinib and nilotinib reversed MRP7-mediated multidrug resistance. Our MTT assay results indicated that MRP7 expression in HEK-MRP7-2 cells was not significantly altered by incubation with 5 microM of imatinib or nilotinib for up to 72 hours. In addition, imatinib and nilotinib (1-5 microM) produced a significant concentration-dependent reversal of MRP7-mediated multidrug resistance by enhancing the sensitivity of HEK-MRP7-2 cells to paclitaxel and vincristine. Imatinib and nilotinib, at 5 microM, significantly increased the accumulation of [(3)H]-paclitaxel in HEK-MRP7-2 cells. The incubation of the HEK-MRP7-2 cells with imatinib or nilotinib (5 microM) also significantly inhibited the efflux of paclitaxel. CONCLUSIONS: Imatinib and nilotinib reverse MRP7-mediated paclitaxel resistance, most likely due to their inhibition of the efflux of paclitaxel via MRP7. These findings suggest that imatinib or nilotinib, in combination with other antineoplastic drugs, may be useful in the treatment of certain resistant cancers.

Cepharanthine is a potent reversal agent for MRP7(ABCC10)-mediated multidrug resistance.

Multidrug resistance protein 7 (MRP7; ABCC10) is an ABC transporter that confers resistance to anticancer agents such as the taxanes. We previously reported that several inhibitors of P-gp and MRP1 were able to inhibit the in vitro transport of E(2)17betaG by MRP7 in membrane vesicles transport assays. However, compounds that are able to reverse MRP7-mediated cellular resistance have not been identified. In this study, we examined the effects of cepharanthine (6',12'-dimethoxy-2,2'-dimethyl-6,7-[methylenebis(oxy)]oxyacanthan), an herbal extract isolated from Stephania cepharantha Hayata, to reverse paclitaxel resistance in MRP7-transfected HEK293 cells. Cepharanthine, at 2microM, completely reversed paclitaxel resistance in MRP7-transfected cells. In contrast, the effect of cepharanthine on the parental transfected cells was significantly less than that on the MRP7-transfected cells. In addition, cepharanthine significantly increased the accumulation of paclitaxel in MRP7-transfected cells almost to the level of control cells in the absence of cepharanthine. The efflux of paclitaxel from MRP7-transfected cells was also significantly inhibited by cepharanthine. The ability of cepharanthine to inhibit MRP7 was analyzed in membrane vesicle assays using E(2)17betaG, an established substrate of MRP7, as a probe. E(2)17betaG transport was competitively inhibited by cepharanthine with a K(i) value of 4.86microM. These findings indicate that cepharanthine reverses MRP7-mediated resistance to paclitaxel in a competitive manner.

Proteome analysis of multidrug resistance of human oral squamous carcinoma cells using CD147 silencing.

There is a correlation between the multidrug-resistance (MDR) of cancer cells and their enhanced invasive or metastatic potential. We studied the expression of CD147, a plasma membrane glycoprotein that plays a key role in tumor metastasis by stimulating the production of matrix metalloproteinases (MMPs), in sensitive human oral squamous KB and MDR derivative KB/V cells. Reverse transcription-PCR and flow cytometric analysis revealed that KB/V cells expressed CD147 at significantly higher levels than their parental KB cells. Using stable RNA interference, we succeeded in establishing a CD147 knock-down KB/V cell line (KB/VsiCD147). MTT colorimetric assay showed an increase in the chemosensitivity to vincristine (VCR), all transretinoic acid (ATRA), taxol, and 5-fluorouracil (5-Fu) of KB/VsiCD147 cells. Proteome analysis of KB, KB/V, and KB/VsiCD147 cell lines identified 21 differently expressed proteins. The enhanced expression of representative active proteins, GRP75 and CyPA, was confirmed by Western blotting and RT-PCR. In addition, pretreatment of KB/V cells with a CyPA-binding immunosuppressive drug, cyclosporine A (CsA), enhanced their chemosensitivity to VCR and 5-Fu. We document an abundance of molecules that interact with CD147 in the MDR of human oral squamous carcinoma cells. Additional studies are needed to investigate these novel target proteins of CD147.