The Facilitates Chromatin Transcription (FACT) chromatin remodeling complex, comprised of two subunits, SSRP1 and SPT16, is involved in transcription, replication and DNA repair. We recently showed that curaxins, small molecules with anti-cancer activity, target FACT and kill tumor cells in a FACT-dependent manner. We also found that FACT is overexpressed in human and mouse tumors and that tumor cells are sensitive to FACT downregulation. To clarify the clinical potential of FACT inhibition, we were interested in physiological role(s) of FACT in multicellular organisms. We analyzed SSRP1 and SPT16 expression in different cells, tissues and conditions using Immunohistochemical (IHC) staining of mouse and human tissues and analysis of publically available high-content gene expression datasets. Both approaches demonstrated coordinated expression of the two FACT subunits, which was primarily associated with the stage of cellular differentiation. Most cells of adult tissues do not have detectable protein level of FACT. High FACT expression was associated with stem or less-differentiated cells, while low FACT levels were seen in more differentiated cells. Experimental manipulation of cell differentiation and proliferation in vitro, as well as tissue staining for the Ki67 proliferation marker, showed that FACT expression is related more to differentiation than to proliferation. Thus, FACT may be part of a stem cell-like gene expression signature and play a role in maintaining cells in an undifferentiated state, which is consistent with its potential role as an anti-cancer target.

Reported herein are the results of a structured literature review that was undertaken to (a) determine if human buccal (mouth) cell changes are associated with smoking and smokeless (''chewing'') tobacco, (b) tabulate different buccal cell alterations that have been reported, (c) delineate buccal cell assays that have been used successfully, (d) determine whether buccal cell changes correlate with oral cancer as defined in clinicopathologic investigations, and (e) assess the feasibility of developing a high-throughput buccal cell assay for screening smokers for the early detection of oral cancer. The results of the studies reported herein have established that diverse buccal cell changes are associated with smoking and smokeless tobacco. This review documents also that buccal cells have been collected in a noninvasive manner, and repetitively for serial studies, from different sites of the mouth (e.g., cheek, gum, and tongue) and from normal tissue, preneoplastic lesions (leukoplakia), and malignant tumors. Tobacco-associated genetic mutations and nongenetic changes have been reported; a partial listing includes (a) micronuclei, (b) bacterial adherence, (c) genetic mutations, (d) DNA polymorphisms, (d) carcinogen-DNA adducts, and (e) chromosomal abnormalities. Clinical studies have correlated buccal cell changes with malignant tumors, and some oral oncologists have reported that the buccal cell changes are practical biomarkers. Summarily, the literature has established that buccal cells are useful not only for characterizing the molecular mechanisms underlying tobacco-associated oral cancers but also as exfoliative cells that express diverse changes that offer promise as candidate biomarkers for the early detection of oral cancer. (Cancer Epidemiol Biomarkers Prev 2006;15(6):1061 -77)

The TOR (Target of Rapamycin) pathway accelerates cellular and organismal aging. Similar to rapamycin, p53 can inhibit the mTOR pathway in some mammalian cells. Mice lacking one copy of p53 (p53+/− mice) have an increased cancer incidence and a shorter lifespan. We hypothesize that rapamycin can delay cancer in heterozygous p53+/− mice. Here we show that rapamycin (given in a drinking water) extended the mean lifespan of p53+/− mice by 10% and when treatment started early in life (at the age less than 5 months) by 28%. In addition, rapamycin decreased the incidence of spontaneous tumors. This observation may have applications in management of Li-Fraumeni syndrome patients characterized by heterozygous mutations in the p53 gene.

Endogenously generated protoporphyrin IX (PpIX) from exogenous ALA can be an effective photosensitizer. PpIX accumulation is inversely dependent on available intracellular iron, which is required for the conversion of PpIX to heme. Iron also is necessary for cell replication. Since iron can be toxic, intracellular iron levels are tightly controlled. Activated and proliferating cells respond to the demand for intracellular iron by upregulating membrane expression of the transferrin receptor (CD71) which is needed for iron uptake. We predicted that activated lymphocytes (CD71+) would preferentially accumulate PpIX because of their lower intracellular iron levels and because of competition for iron between ALA-induced heme production and cellular growth processes. Thus, the CD71+ cells could serve as PDT targets. Stimulation of human peripheral blood lymphocytes (PBL) with the mitogens, phytohemagglutinin A, concanavalin A and pokeweed prior to incubation with ALA results in PpIX accumulation correlating with level of activation. Activated lymphocytes expressing high levels of surface CD71 transferrin receptors generated more PpIX than those with low CD71 expression. Incubating activated cells in transferrin depleted medium (thereby decreasing the iron availability) further increased PpIX levels. Malignant, CD71+ T lymphocytes from a patient with cutaneous T-cell lymphoma (CTCL)/Sezary syndrome also accumulated increased PpIX levels in comparison to normal lymphocytes. PDT of activated lymphocytes and Sezary cells after ALA incubation demonstrated preferential killing compared to normal, unstimulated PBL. These findings suggest a possible mechanism for the selectivity of ALA PDT for activated CD71+ cells. They also indicate a clinical use for ALA-PDT in therapy directed towards the malignant lymphocytes in leukemias and lymphomas, and as animmunomodulatory agent.

Recent discoveries have revealed the key role of mTOR (target of rapamycin) in aging. Furthermore, rapamycin extends lifespan in mice, especially in female mice. Here, we treated obese male mice on high-fat diet with rapamycin given intermittently: either weekly (once a week) or alternating bi-weekly (three injections every other week). While only marginally reducing obesity, intermittent administration of rapamycin significantly extended lifespan. Significance was achieved for weekly treated group and for the three rapamycin-received groups combined. In weekly treatment group, 100% mice were alive by the age of 2 years, whereas 60% of mice died in untreated group by this age. The effect of weekly treatment on survival was highly significant and cannot be fully explained by partial reduction in obesity. Alternating bi-weekly treatments seem to be less effective than weekly treatment, although effects of additional factors (see Discussion) may not be excluded. After one year of treatment, all survived mice were sacrificed 8 days after the last administration of rapamycin to avoid its direct interference with parameters examined. Fasting levels of cardiac and hepatic p-S6, a marker of mTORC1 activity, were lower in weekly treatment group compared with control mice. In contrast, levels of p-Akt (S473), glucose, triglycerides and insulin were unchanged, whereas leptin and IGF-1 tended to be lower. Thus, weekly treatment with rapamycin may slow down aging in obese male mice on high-fat diet.

Although breast cancer (BrCa) may be detected at an early stage, there is a shortage of markers that predict tumor aggressiveness and a lack of targeted therapies. Histone chaperone FACT, expressed in a limited number of normal cells, is overexpressed in different types of cancer, including BrCa. Recently, we found that FACT expression in BrCa correlates with markers of aggressive BrCa, which prompted us to explore the consequences of FACT inhibition in BrCa cells with varying levels of FACT.FACT inhibition using a small molecule or shRNA caused reduced growth and viability of all BrCa cells tested. Phenotypic changes were more severe in high- FACT cells (death or growth arrest) than in low-FACT cells (decreased proliferation). Though inhibition had no effect on the rate of general transcription, expression of individual genes was changed in a cell-specific manner. Initially distinct transcriptional profiles of BrCa cells became similar upon equalizing FACT expression. In high-FACT cells, FACT supports expression of genes involved in the regulation of cell cycle, DNA replication, maintenance of an undifferentiated cell state and regulated by the activity of several proto-oncogenes. In low-FACT cells, the presence of FACT reduces expression of genes encoding enzymes of steroid metabolism that are characteristic of differentiated mammary epithelia.Thus, we propose that FACT is both a marker and a target of aggressive BrCa cells, whose inhibition results in the death of BrCa or convertion of them to a less aggressive subtype.

Chronic inflammation associated with cigarette smoke fosters malignant transformation and tumor cell proliferation and promotes certain nonneoplastic pulmonary diseases. The question arises as to whether chronic inflammation and/or colonization of the airway can be attributed, at least in part, to tobacco-associated microbes (bacteria, fungi, and spores) and/or microbial toxins (endotoxins and mycotoxins) in tobacco. To address this question, a literature search of documents in various databases was performed. The databases included PubMed, Legacy Tobacco Documents Library, and US Patents. This investigation documents that tobacco companies have identified and quantified bacteria, fungi, and microbial toxins at harvest, throughout fermentation, and during storage. Also characterized was the microbial flora of diverse smoking and smokeless tobacco articles. Evidence-based health concerns expressed in investigations of microbes and microbial toxins in cigarettes, cigarette smoke, and smokeless tobacco products are reasonable; they warrant review by regulatory authorities and, if necessary, additional investigation to address scientific gaps.

Males, who are bigger and stronger than females, die younger in most species from flies to mammals including humans. Cellular mass growth is driven in part by mTOR (Target of Rapamycin). When developmental growth is completed, then, instead of growth, mTOR drives aging, manifested by increased cellular functions, such as hyper-secretion by fibroblasts, thus altering homeostasis, leading to age-related diseases and death. We hypothesize that MTOR activity is elevated in male mice compared with females. Noteworthy, 6 months old males were 28 % heavier than females. Also levels of phosphorylated S6 (pS6) and phospho-AKT (p-AKT, Ser 473), markers of the mTOR activity, were higher in male organs tested. Levels of pS6 were highly variable among mice and correlated with body weight and p-AKT. With age, the difference between levels of pS6 between sexes tended to minimize, albeit males still had hyperactive mTOR. Unlike fasting, the intraperitoneal (i.p.) administration of rapamycin eliminated pS6 in all organs of all females measured by immunoblotting and immunohistochemistry without affecting p-AKT and blood insulin. Although i.p. rapamycin dramatically decreased levels of pS6 in males too, it was still detectable by immunoblotting upon longer exposure. Our study demonstrated that both tissue p-AKT and pS6 were higher in young males than young females and were associated with increased body weight and insulin. These data can explain larger body size and faster aging in males. Our data suggest higher efficacy of rapamycin compared to fasting. Higher sensitivity of females to rapamycin may explain more pronounced life extension by rapamycin observed in females compared to males in several studies.