Genomic characterization of clonal evolution during oropharyngeal carcinogenesis driven by human papillomavirus 16.

Secondary prevention via earlier detection would afford the greatest chance for a cure in premalignant lesions. We investigated the exomic profiles of non-malignant and malignant changes in head and neck squamous cell carcinoma (HNSCC) and the genomic blueprint of human papillomavirus (HPV)-driven carcinogenesis in oropharyngeal squamous cell carcinoma (OPSCC). Whole-exome (WES) and whole-genome (WGS) sequencing were performed on peripheral blood and adjacent non-tumor and tumor specimens obtained from eight Korean HNSCC patients from 2013 to 2015. Next-generation sequencing yielded an average coverage of 94.3× for WES and 35.3× for WGS. In comparative genomic analysis of non-tumor and tumor tissue pairs, we were unable to identify common cancer-associated early mutations and copy number alterations (CNA) except in one pair. Interestingly, in this case, we observed that non-tumor tonsillar crypts adjacent to HPV-positive OPSCC appeared normal under a microscope; however, this tissue also showed weak p16 expression. WGS revealed the infection and integration of high-risk type HPV16 in this tissue as well as in the matched tumor. Furthermore, WES identified shared and tumor-specific genomic alterations for this pair. Clonal analysis enabled us to infer the process by which this transitional crypt epithelium (TrCE) evolved into a tumor; this evolution was accompanied by the subsequent accumulation of genomic alterations, including an ERBB3 mutation and large-scale CNAs, such as 3q27-qter amplification and 9p deletion. We suggest that HPV16-driven OPSCC carcinogenesis is a stepwise evolutionary process that is consistent with a multistep carcinogenesis model. Our results highlight the carcinogenic changes driven by HPV16 infection and provide a basis for the secondary prevention of OPSCC. [BMB Reports 2018; 51(11): 584-589].

Evidence of effectiveness of preventive dental care in reducing dental treatment use and related expenditures.

OBJECTIVES: Preventive dental health services are intended to reduce the likelihood of development of tooth decay and the need for more intensive treatment overtime. The evidence on the effectiveness of preventive dental care in reducing treatment services and expenditures is lagging for adults, particularly those with lower incomes and chronic conditions. We assessed the impact of preventive dental services on dental treatment service use and expenditures overall and by category of service. METHODS: We calculated the annual numbers of preventive (periodic diagnostic and prophylactic procedures) and treatment (restorative, surgery, prosthodontic, endodontic, and periodontic) services per beneficiary using Medicaid enrollment and claims data for beneficiaries with three categories of conditions (diabetes, heart disease, and respiratory disease) from 10 largest California counties. We used Cragg hurdle exponential regression models controlling for past service use, demographics, length of enrollment, and county. RESULTS: We found that using preventive services in 2005-2007 was associated with higher likelihood and number of treatment dental services used, but associated with lower treatment expenditures in 2008. The reduction in expenditures was noted only in restorative, prosthodontics, and periodontic services. CONCLUSIONS: The findings provide much needed evidence of the contribution of preventive dental care in maintaining oral health of low-income adults with chronic conditions and potential for savings to the Medicaid program. Providing lower cost preventive dental care to the individuals with chronic conditions would achieve better oral health and lower treatment expenditures.

Ad5/35E1aPSESE4: A novel approach to marking circulating prostate tumor cells with a replication competent adenovirus controlled by PSA/PSMA transcription regulatory elements.

Circulating tumor cells serve as useful biomarkers with which to identify disease status associated with survival, metastasis and drug sensitivity. Here, we established a novel application for detecting PSA/PSMA-positive prostate cancer cells circulating in peripheral blood employing an adenovirus called Ad5/35E1aPSESE4. Ad5/35E1aPSESE4 utilized PSES, a chimeric enhancer derived from PSA/PSMA promoters that is highly active with and without androgen. A fluorescence signal mediated by GFP expression upon Ad5/35E1aPSESE4 infection was selectively amplified in PSA/PSMA-positive prostate cancer cells in vitro and ex vivo. Furthermore, for the in vivo model, blood drawn from TRAMP was tested for CTCs with Ad5/35E1aPSESE4 infection and was positive for CTCs at week 16. Validation was performed on patient blood at various clinical stages and found out 1-100 CTCs expressing GFP upon Ad5/35E1aPSESE4 infection. Interestingly, CTC from one patient was confirmed to be sensitive to docetaxel chemotherapeutic reagent and to abundantly express metastasis-related genes like MMP9, Cofilin1, and FCER1G through RNA-seq. Our study established that the usage of Ad5/35E1aPSESE4 is effective in marking PSA/PSMA-positive prostate cancer cells in patient blood to improve the efficacy of utilizing CTCs as a biomarker.

Trends in the supply of dentists in California.

More than 35,000 dentists were licensed to practice in California in 2012, a number higher than in any other state and representing about 15.6 percent of the total number of dentists nationwide. Despite these numbers, concerns over a sufficient supply of dentists in the state have not diminished. These concerns are due in part to the uneven distribution of dentists in areas with the highest level of need, as well as to demographic and practice characteristics that may limit availability of the dental workforce. This policy brief provides an overview of changes in selected demographic and practice characteristics of California dentists from 2008 to 2012, as well as in the distribution of dentists in California regions. The findings indicate an outward migration of dentists from California, a slowly aging workforce, and low dentist-to-population ratios in some regions of California. These findings highlight the need for the continuation and fine-tuning of policies aimed at both attracting young dentists to areas with low supply and retaining existing dentists in the state.

The impact of Medicaid insurance coverage on dental service use.

The new comprehensive health reform, beginning in 2014, will require Medicaid to expand all elements of coverage to individuals with incomes up to 133 percent of the federal poverty line. With millions more individuals gaining eligibility for adult Medicaid dental benefits, generating an unbiased estimate of the elasticity of demand for dental services is critical. The causal relationship between access to adult Medicaid dental benefits and usage of dental services for low-income adults is estimated, using difference-in-differences estimation procedures to exploit the state-level variation in adult Medicaid dental benefits. Results suggest that adult Medicaid dental benefits increase the probability of a dental visit within 12 months by 16.4-22 percent. A variety of robustness checks are invoked to confirm the finding.

Effect of butyrate on the heregulin/ErbB-mediated proliferation of human colorectal cancer cells.

The expression of ErbB proteins, together with heregulin, was found to be increased in colon cancer cells compared with normal mucosa, and heregulin-stimulated activation of ErbB signaling was observed to contribute to the proliferation of colon cancer cells. Butyrate produced during the fermentation of fiber by intestinal bacteria is known to exert diverse anticancer effects, including the induction of differentiation, cell cycle arrest and growth suppression in human colon cancer cells. In this study, we investigated whether butyrate affects the heregulin/ErbB-mediated proliferation of colon cancer cells. The growth of human CaCo-2 and SNU-C4 colon cancer cells, which express ErbB1-4 proteins, was stimulated by heregulin in a concentration-dependent manner. Pretreatment with sodium butyrate abolished heregulin-stimulated proliferation in both cell lines. Although butyrate did not alter ErbB protein expression and activation, it did block the prolonged activation of Akt and Erk1/2, which are known to be important ErbB downstream molecules mediating heregulin-stimulated proliferation. Our data suggest that the inhibitory effects of butyrate on the heregulin-stimulated proliferation of colorectal cancer cells are, in part, associated with the suppression of the Akt and Erk signaling pathway. Butyrate may act as a preventive and therapeutic agent in the progression of colorectal cancer through the regulation of heregulin-stimulated mitogenic signaling.

Alpha-tocopheryl succinate sensitizes human colon cancer cells to exisulind-induced apoptosis.

Sulindac sulfone (also known as exisulind) and its chemical derivatives are promising anticancer agents capable of inducing apoptosis in a variety of malignant cell types with minimal toxicity to normal cells. Here, we tested the ability of alpha-tocopheryl succinate (TOS), another promising anticancer agent, to sensitize colon cancer cells to exisulind-induced apoptosis. We found that sub-apoptotic doses of TOS greatly enhanced exisulind-induced growth suppression and apoptosis in the HCT116, LoVo and SNU-C4 human colon cancer cell lines. Our results revealed that this was accounted for primarily by an augmented cleavage of poly(ADP-ribose) polymerase (PARP) and enhanced activation of caspase-8, -9 and -3. Pretreatment with z-VAD-FMK (a pan-caspase inhibitor), z-IETD-FMK (a caspase-8 inhibitor) or z-LEHD-FMK (a caspase-9 inhibitor) blocked TOS and exisulind cotreatment-induced PARP cleavage and apoptosis. Furthermore, TOS/exisulind cotreatment induced JNK phosphorylation, while pretreatment with SP600151 (a JNK inhibitor) partially blocked cotreatment-induced caspase-dependent PARP cleavage and apoptosis. Taken together, these findings indicate that TOS sensitizes human colon cancer cells to exisulind-induced apoptosis. Apoptotic synergy induced by exisulind plus TOS seems likely to be mediated through a mechanism involving activation of caspases and JNK.

Alpha-tocopheryl succinate, in contrast to alpha-tocopherol and alpha-tocopheryl acetate, inhibits prostaglandin E2 production in human lung epithelial cells.

The production of prostaglandin E2 (PGE2), a key proinflammatory mediator, is regulated by the availability of its substrate, arachidonic acid (AA), and the activity of the enzyme cyclooxygenase (COX). Increased PGE2 production and COX-2 expression have been observed frequently in specimens from lung cancer patients. Agents that decrease PGE2 production may prevent the initiation and progression of lung cancer. We, therefore, tested the effects of alpha-tocopherol (alphaTOL) analogs on PGE2 production in human lung epithelial cells. Alpha-tocopheryl succinate (alphaTOS), but not alphaTOL or alpha-tocopheryl acetate (alphaTOA), inhibited the phorbol 12-myristate 13-acetate (PMA)-stimulated PGE2 production in three human lung epithelial cell lines (BEAS-2B, H460 and A549 cells). The effect of these compounds on PGE2 production was not correlated with their antioxidant activities, since alphaTOS alone did not inhibit PMA-induced generation of reactive oxygen species. alphaTOS had no effect on PMA-induced AA release or COX-2 expression, although post-incubation with alphaTOS inhibited COX activity and prostaglandin (PGE2 and PGF(2alpha)) production in PMA-stimulated cells. alphaTOS also blocked the COX activity in A549 cells with endogenous high levels of COX enzymes in the absence of PMA stimulation. In addition, the ability of alphaTOS to inhibit COX was affected by AA concentration, suggesting that alphaTOS may compete with AA for interaction with COX proteins. These results suggest that alphaTOS inhibits COX activity, thereby inhibiting PGE2 production in human lung epithelial cells, despite the lack of antioxidant activity. Administration of alphaTOS may block inflammatory responses mediated by PGE2, thereby inhibiting the initiation and progression of lung cancer.

5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-trifluoromethylpyrazole acts in a reactive oxygen species-dependent manner to suppress human lung cancer growth.

PURPOSE: 5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-trifluoromethylpyrazole (SC-560) is a structural analog of celecoxib. Recent studies suggested that SC-560 inhibits the in vivo proliferation of colon and breast cancer cells to an extent similar to that observed in celecoxib, and that SC-560 exerts their growth inhibitory effects in a cyclooxygenase-independent manner. METHODS: In the current study, we sought to investigate the mechanism by which SC-560 inhibits the growth of human lung cancer cells. RESULTS: SC-560 more potently inhibited the growth of human A549, H460, and H358 lung cancer cell lines compared with that of human BEAS-2B normal bronchial epithelial cells. SC-560-induced growth inhibition was mainly due to the induction of cell-cycle arrest at the G1 phase without apoptosis induction. SC-560 rapidly and dose-dependently induced the generation of reactive oxygen species (ROS), followed by accumulation of cells at the G1 phase. Antioxidant pretreatment blocked the cell-cycle arrest and growth inhibition induced by SC-560. Combination treatment with other ROS-inducing agents such as alpha-tocopheryl succinate (TOS) augmented cellular response against SC-560, leading to synergistic apoptosis induction and growth suppression. Our data also showed that the apoptosis induced by combination treatment with SC-560 and TOS was mediated through ROS-dependent caspase activation. CONCLUSION: Collectively, our results demonstrate that SC-560 acts in a ROS-dependent manner to induce growth suppression in human lung cancer cells.

Enhanced anticancer efficacy of alpha-tocopheryl succinate by conjugation with polyethylene glycol.

Alpha-tocopheryl polyethylene glycol succinate (TPGS) has been used to enhance the bioavailability of poorly absorbed drugs and as a vehicle for drug delivery systems. In response to recent reports that alpha-tocopheryl succinate (TOS) acts as an anticancer agent, we investigated whether its polyethylene glycol (PEG) conjugate, TPGS, also possesses anticancer activity. TPGS inhibited the growth of human lung carcinoma cells implanted in nude mice, and in an in vitro cell culture, even more potently than TOS. The time-dependent uptake of TPGS into cells did not differ from that of TOS, indicating that the enhanced antitumor efficacy of TPGS was not due to its increased uptake into cells. Compared with TOS, TPGS was more effective at inducing apoptosis and the generation of reactive oxygen species, suggesting that the superior anticancer efficacy of TPGS is associated with its increased ability to induce apoptosis. Our data suggest that further studies assessing the potential usefulness of TPGS in cancer therapeutics are warranted, since its use as a vehicle in the formulation of anticancer drugs may provide an effective way to improve their therapeutic efficacy.

Role of reactive oxygen species in the induction of apoptosis by alpha-tocopheryl succinate.

Alpha-tocopheryl succinate (TOS), a vitamin E analog, is a promising anticancer agent due to its abilities to inhibit proliferation and to induce apoptosis in a variety of human malignant cell lines, while being relatively less active toward normal cells. However, the molecular mechanisms underlying the apoptotic effects of TOS are not precisely understood. Reports that TOS can generate reactive oxygen species (ROS) prompted us to investigate the role of ROS in TOS-induced apoptosis in cancer cells. We found that the human lung cancer A549 and H460 cell lines were much more sensitive to TOS-induced apoptosis than the human glioblastoma T98G and U87MG cell lines. Our data suggested that the differential TOS sensitivity was not caused by differences in the uptake and retention of TOS between TOS-sensitive and -resistant cancer cells. The differential ability of cancer cells to generate ROS in response to TOS appears to be an important factor in determining the susceptibility of cells to TOS-induced apoptosis. Our results further suggest that TOS-induced generation of ROS is involved in caspase-independent apoptosis. Taken together, our findings suggest an important role of ROS generation in TOS-induced, caspase-independent apoptosis of cancer cells.