Effects of α-adrenoceptor antagonists on ABCG2/BCRP-mediated resistance and transport

Getting to the Heart of the Matter: A Review of Drug Interactions Between HIV Antiretrovirals and Cardiology Medications

The past 20 years have seen remarkable advances in the treatment of HIV such that most people diagnosed with HIV today can live long, healthy lives by taking antiretrovirals which are usually life-long. Advancements in antiretroviral therapy include the availability of well tolerated, single tablet regimens that are associated with a lower risk of drug-drug interactions. Despite this, many people living with HIV infection might be taking antiretroviral agents that are associated with significant drug-drug interactions. Because HIV infection itself is associated with cardiovascular complications and this population is living longer, concomitant use of antiretrovirals and medications to treat cardiovascular-related diseases is often required. For this reason, it is imperative that clinicians are aware of the potential for clinically significant drug-drug interactions between antiretroviral agents and cardiac medications as well as the useful HIV drug interaction resources that might provide guidance. Available data on significant interactions are summarized and suggested guidance regarding management is discussed.

Identification of side population cells in human lung adenocarcinoma A549 cell line and elucidation of the underlying roles in lung cancer

The present study aimed to isolate and characterize side population (SP) cells in the human lung cancer A549 cell line, and elucidate the molecular mechanism of SP cells underlying lung cancer. The SP and non-SP (NSP) cells in A549 cells were isolated and their differentiation was analyzed by fluorescence-activated cell sorting. An in vitro plate clone assay, Matrigel^® Transwell assay and chemoresistance analysis of the sorted SP and NSP cells were performed. In addition, the sorted SP and NSP cells were injected into BALB/c nude mice to detect their tumorigenic potential in vivo. The expression of ATP-binding cassette sub-family G member 2 (ABCG2) in transplanted tumors was detected by immunohistochemistry. The SP and NSP cells were successfully isolated. The results demonstrated that SP cells accounted for 1.09% of live A549 cells. SP cells produced SP and NSP cells, while NSP cells only produced NSP cells. In addition, SP cells formed more colonies, exhibited improved invasive ability and increased levels of chemoresistance compared with NSP cells in vitro. SP cells demonstrated a higher tumorigenic potential in BALB/c nude mice, and the number of ABCG2-positive cells in the SP xenograft tumors were significantly increased compared with that in the NSP xenograft tumors. The present study indicated that SP cells isolated from the human lung cancer A549 cell line demonstrated increased tumorigenicity, and improved invasive ability and chemoresistance compared with NSP cells. In addition, detection of ABCG2 expression may assist in predicting the chemotherapeutic outcome of patients, and serve as a target for treating lung cancer.

Isolation and sequencing of swine carbonic anhydrase VI, an enzyme expressed in the swine kidney

Background

Carbonic anhydrase VI (CA-VI) is produced by the salivary gland and is secreted into the saliva. Although CA-VI is found in the epithelial cells of distal straight tubule of swine kidneys, the exact function of CA-VI in the kidneys remains unclear.

Results

CA-VI was located in the epithelial cells of distal straight tubule of swine kidneys.

A full-length cDNA clone of CA-VI was generated from the swine parotid gland by reverse transcription polymerase chain reaction, using degenerate primers designed based on conserved regions of the same locus in human and bovine tissues.

The cDNA sequence was 1348 base pairs long and was predicted to encode a 317 amino acid polypeptide with a putative signal peptide of 17 amino acids. The deduced amino acid sequence of mature CA-VI was most similar (77.4%) to that of human CA-VI. CA-VI expression was confirmed in both normal and nephritic kidneys, as well as parotid. As the primers used in this study spanned two exons, the influence of genomic DNA was not detected. The expression of CA-VI was demonstrated in both normal and nephritic kidneys, and mRNA of CA-VI in the normal kidneys which was the normalised to an endogenous β–actin was 0.098 ± 0.047, while it was significantly lower in the diseased kidneys (0.012 ± 0.007). The level of CA-VI mRNA in normal kidneys was 19-fold lower than that of the parotid gland (1.887).

Conclusions

The localisation of CA-VI indicates that it may play a specialised role in the kidney.

Everolimus-induced human keratinocytes toxicity is mediated by STAT3 inhibition

Background

Mammalian target of rapamycin (mTOR) inhibitors are associated with dermatological adverse events. The chief aim of this study was to examine the relation between the signal transducer and activator of transcription 3 (STAT3) protein and the dermatological adverse events associated with the mTOR inhibitor everolimus.

Methods

We evaluated the effects of STAT3 activity and related signal transduction activities on everolimus-induced cell growth inhibition in the human keratinocyte HaCaT cell line via a WST-8 assay, and on signal transduction mechanisms involved in everolimus treatments via a western blot analysis. Apoptosis was evaluated using an imaging cytometric assay.

Results

The cell growth inhibitory effects of everolimus were enhanced by stattic or STA-21, which are selective inhibitors of STAT3, treatment in HaCaT cells, although such effects were not observed in Caki-1 and HepG2 cells. Phosphorylation at tyrosine 705 of STAT3 was decreased by treatment with everolimus in a dose-dependent manner in HaCaT cells; in contrast, phosphorylation at serine 727 was not decreased by everolimus, but slightly increased. Furthermore, we found that pretreatment of p38 MAPK inhibitor and transfection with constitutively active form of STAT3 in HaCaT cells resisted the cytostatic activity of everolimus.

Conclusions

These findings suggest that STAT3 activity may be a biomarker of everolimus-induced dermatological toxicity.

Heat shock proteins and heat shock factor 1 in carcinogenesis and tumor development: an update

Heat shock proteins (HSP) are a subset of the molecular chaperones, best known for their rapid and abundant induction by stress. HSP genes are activated at the transcriptional level by heat shock transcription factor 1 (HSF1). During the progression of many types of cancer, this heat shock transcriptional regulon becomes co-opted by mechanisms that are currently unclear, although evidently triggered in the emerging tumor cell. Concerted activation of HSF1 and the accumulation of HSPs then participate in many of the traits that permit the malignant phenotype. Thus, cancers of many histologies exhibit activated HSF1 and increased HSP levels that may help to deter tumor suppression and evade therapy in the clinic. We review here the extensive work that has been carried out and is still in progress aimed at (1) understanding the oncogenic mechanisms by which HSP genes are switched on, (2) determining the roles of HSF1/HSP in malignant transformation and (3) discovering approaches to therapy based on disrupting the influence of the HSF1-controlled transcriptome in cancer.