Isoliquiritigenin as a cause of DNA damage and inhibitor of ataxia-telangiectasia mutated expression leading to G2/M phase arrest and apoptosis in oral squamous cell carcinoma

BACKGROUND

Isoliquiritigenin (ISL), a natural compound extracted from licorice, has chemopreventive and antitumor activities. The purpose of this study was to investigate the anticancer effect of ISL on human oral squamous cell carcinoma (OSCC).

METHODS

The anti-OSCC effects of ISL were evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test, flow cytometry, reverse transcription-polymerase chain reaction, Western blotting, promoter activity, terminal deoxynucleotidyl transferase dUTP nick-end labeling assay, malignant phenotype analysis, microRNA, and xenografting.

RESULTS

ISL induced OSCC cell cycle G2/M phase arrest, apoptosis, and DNA damage. However, the DNA repair-associated ataxia telangiectasia mutated (ATM) and phospho-ATM were downregulated, ATM mRNA remained unchanged, and the downstream signals were inhibited. ATM recovered when the caspase activity was blocked by Z-DVED-FMK. A low dose of ISL inhibited OSCC malignancy in vitro and reduced the tumor size in vivo.

CONCLUSION

ATM was cleaved by ISL-activated caspase, thus inhibiting DNA repair in OSCC cells. Therefore, ISL is a promising chemopreventive agent against oral cancer. © 2015 Wiley Periodicals, Inc. Head Neck 38: E360-E371, 2016.

Routine CD4 cell count monitoring seldom contributes to clinical decision-making on antiretroviral therapy in virologically suppressed HIV-infected patients

OBJECTIVES

In Australia, CD4 cell count is monitored approximately every 6 months in HIV-infected patients during antiretroviral therapy (ART). The aim of this study was to determine if routine CD4 monitoring contributed to decisions on changes to ART, and to estimate how reduced CD4 monitoring could contribute to cost savings in Australia.

METHODS

We conducted a retrospective cohort analysis investigating all HIV-infected patients who attended the Melbourne Sexual Health Centre (MSHC) in Australia from 1 April 2011 to 1 October 2013. We reviewed the electronic medical records of all patients who changed or stopped antiretroviral regimens during this time period to determine whether CD4 cell count could have contributed to this clinical decision.

RESULTS

Among 1004 patients with HIV infection on ART, none [95% confidence interval (CI) 0-2.3%] of the 162 clinical decisions to change or stop treatment were influenced by CD4 cell counts. Reducing the current biannual CD4 monitoring strategy to annually could potentially save ∼AU$ 1.5 million (US$ 1.4 million) each year in Australia [i.e. ∼AU$ 74 700 (US$ 67 700) could be saved per 1000 HIV-infected patients during ART].

CONCLUSIONS

Routine CD4 monitoring in HIV-infected patients during ART could be reduced from biannually to annually, as it rarely influences clinical decisions in patients' management. Not only could this avoid patients being unnecessarily anxious about normal fluctuations in their CD4 counts but it would also result in cost savings.

Cloning and expression analysis of Wnt6 and Hox6 during intestinal regeneration in the sea cucumber Apostichopus japonicus

Many developmental genes play important roles in regeneration. Here, we cloned the two developmental genes, Wnt6 and Hox6, from Apostichopus japonicus by rapid amplification of cDNA ends (RACE) polymerase chain reaction (PCR). The Wnt6 full-length cDNA is 1140 bp long with a 1029-bp open reading frame encoding 342 amino acids. The deduced Wnt6 protein contained a 22-amino acid signal peptide and a 274-amino acid mature peptide. The Hox6 (AjHBOX6) full-length cDNA contained 1312 bp with a 966-bp open reading frame encoding 321 amino acids. Its deduced amino acid sequence included one homeodomain (60 amino acids) and three domains with low compositional complexity. Comparison and phylogenetic analysis revealed that Wnt6 and Hox6 in A. japonicus had the nearest relationship to those in sea urchins. Further expression analysis by real-time PCR showed that Wnt6 and Hox6 were apparently upregulated during intestine regeneration, which suggested that they were involved in the intestinal regeneration of sea cucumbers.

Curcumin-loaded nanoparticles induce apoptotic cell death through regulation of the function of MDR1 and reactive oxygen species in cisplatin-resistant CAR human oral cancer cells

Curcumin is a polyphenolic compound which possesses anticancer potential. It has been shown to induce cell death in a variety of cancer cells, however, its effect on CAL27‑cisplatin-resistant human oral cancer cells (CAR cells) has not been elucidated to date. The low water solubility of curcumin which leads to poor bioavailability, however, has been highlighted as a major limiting factor. In this study, we utilized water-soluble PLGA curcumin nanoparticles (Cur-NPs), and investigated the effects of Cur-NPs on CAR cells. The results showed Cur-NPs induced apoptosis in CAR cells but exhibited low cytotoxicity to normal human gingival fibroblasts (HGFs) and normal human oral keratinocytes (OKs). Cur-NPs triggered DNA concentration, fragmentation and subsequent apoptosis. Compared to untreated CAR cells, a more detectable amount of Calcein-AM accumulation was found inside the treated CAR cells. Cur-NPs suppressed the protein and mRNA expression levels of MDR1. Both the activity and the expression levels of caspase-3 and caspase-9 were elevated in the treated CAR cells. The Cur-NP-triggered apoptosis was blocked by specific inhibitors of pan-caspase (z-VAD-fmk), caspase-3 (z-DEVD-fmk), caspase-9 (z-LEHD-fmk) and antioxidant agent (N-acetylcysteine; NAC). Cur-NPs increased reactive oxygen species (ROS) production, upregulated the protein expression levels of cleaved caspase-3/caspase-9, cytochrome c, Apaf-1, AIF, Bax and downregulated the protein levels of Bcl-2. Our results suggest that Cur-NPs triggered the intrinsic apoptotic pathway through regulating the function of multiple drug resistance protein 1 (MDR1) and the production of reactive oxygen species (ROS) in CAR cells. Cur-NPs could be potentially efficacious in the treatment of cisplatin-resistant human oral cancer.

Size of anal squamous cell carcinomas at diagnosis: a retrospective case series

Anal squamous cell carcinoma is more common in HIV-positive homosexual men than in the general population and prognosis worsens with increasing tumour size. To identify opportunities for earlier diagnosis, we aimed to determine size and visibility of anal squamous cell carcinoma at diagnosis. We conducted a retrospective review of medical records between 1992 and 2010 from one hospital radiotherapy centre, a major centre for HIV care, in Melbourne, Australia. Of 128 cases of anal squamous cell carcinoma, 24 (19%) were in HIV-positive men. At diagnosis, half (52%) of the tumours were externally visible and mean estimated tumour size was 36 mm (29 mm in HIV-positive and 38 mm in HIV-negative patients; p = 0.04) and 114/121 (94%) tumours were 1 cm or larger. The most frequent symptoms were bleeding (43%) and pain (36%) and mean duration of symptoms was 22 weeks. This suggests most anal squamous cell carcinoma were visible or palpable for some time before diagnosis, meaning that screening high-risk groups by anal inspection and palpation is plausible.