Human immunodeficiency virus-1 Tat protein up-regulates interleukin-6 and interleukin-8 expression in human breast cancer cells.

OBJECTIVE: To examine whether HIV-1 Tat protein increases the metastatic potential of human breast cancer cells through induction of pro-inflammatory tumor microenvironment. METHODS: Real-time RT-PCR and ELISA were employed to determine the mRNA and protein expression of IL-6 and IL-8 in highly metastatic human breast cancer cell line, MDA-MB-231. To investigate the transcriptional regulatory mechanisms of Tat-mediated up-regulation of IL-6 and IL-8, EMSA and reporter gene assay were carried out. RESULTS: Exposure of MDA-MB-231 cells to Tat resulted in a significant and dose-dependent up-regulation of IL-6 and IL-8 mRNA and protein expression. HIV-1 Tat protein also markedly increased NF-kappaB DNA-binding activity and transactivation in MDA-MB-231 cells. Additionally, pretreatment with NF-kappaB inhibitors significantly attenuated the ability of Tat to up-regulate IL-6 and IL-8 expression. It was also found that exposure of MDA-MB-231 cells to Tat induced up-regulation of MMP-9 expression at both mRNA and protein levels. CONCLUSIONS: These results suggest that HIV-1 Tat protein up-regulates expression of IL-6 and IL-8 in human breast cancer cells by NF-kappaB-dependent pathway. These data may contribute to exploration of the new molecular mechanisms leading to novel approaches for the therapeutic drug developments specifically targeted against the inflammatory pathways of breast cancer metastasis in AIDS patients.

Acute renal failure in a hypothyroid patient with rhabdomyolysis.

A 49-year-old hypothyroid man developed rhabdomyolysis and acute renal failure. He had been on thyroid replacement therapy for 17 years following removal of a benign pituitary tumor. Rhabdomyolysis was diagnosed by elevated liver enzymes, CPK, and creatinine. The case illustrates how hypothyroidism can cause rhabdomyolysis and subsequently, acute renal failure.

Thymidine analog and multinucleoside resistance mutations are associated with decreased phenotypic susceptibility to stavudine in HIV type 1 isolated from zidovudine-naive patients experiencing viremia on stavudine-containing regimens.

Studies have demonstrated that HIV-1 isolated from subjects experiencing virologic failure on stavudine (d4T)-containing regimens often contains thymidine analog mutations (TAMs), consisting of reverse transcriptase (RT) mutations M41L, D67N, K70R, L210W, T215Y/F, and K219Q/E, previously associated only with zidovudine (ZDV) resistance. In clinical study NZT40012, HIV-1 was isolated from 86 ZDV-naive subjects experiencing viremia on d4T-based therapies (plasma HIV-1 RNA > or =1000 copies/ml) and analyzed to examine the association between RT mutations and phenotypic resistance to d4T. Resistance-associated mutations were analyzed from HIV-1 isolated from 85 subjects. Of these, 24 samples (28%) had TAMs, and 30 samples (35%) had either TAMs and/or the Q151M multinucleoside resistance (MNR) mutation. Phenotypic susceptibility to d4T was determined by two commercially available methods. Statistically significant increases (p < 0.001) in phenotypic fold resistance to d4T were observed in virus with at least one TAM or MNR mutation. However, the mean increases in phenotypic resistance were 4-fold for the Antivirogram assay and 3-fold for the Phenosense HIV assay, only slightly above the levels used to designate decreased susceptibility to d4T. Subjects can experience viremia on d4T-containing regimens with virus exhibiting only small increases in IC(50), suggesting that relatively small changes in viral susceptibility to d4T may influence drug efficacy.