[Effects of FoxO6 on proliferation and invasion of colorectal cancer cells].

Objective: To investigate the effects and the mechanism of FoxO6 on the proliferation and invasion of colorectal cancer cells. Methods: FoxO6 siRNA was transfected into colorectal cancer cell HCT116 and SW480. The overexpression vector pcDNA.3.1-c-Myc was constructed and co-transfected into HCT116 and SW480 cells with FoxO6 siRNA. Real-time fluorescent quantitative PCR (RT-qPCR) and western blot were used to detect the mRNA and protein expressions of FoxO6, c-Myc, and p21 in HCT116 and SW480 cells. Bromodeoxyuridine (BrdU) was used to detect cell proliferation and Transwell assay was performed to detect the invasion ability of these cells. SW480 cells transfected with FoxO6 shRNA lentivirus (LV-FoxO6) and were injected into the right armpit of BAL b/c nude mice to construct a tumor-bearing mode and the tumor volumes were measured on the days of 10, 13, 16, 19, 22, and 25 after injection. Results: The FoxO6 mRNA were 0.91±0.04, 1.72±0.07, and 2.03±0.06, and protein expression were 0.70±0.04, 1.35±0.08, and 1.56±0.07 in normal colon cell FHC, colorectal cancer cells HT116 and SW480, respectively. The protein and mRNA levels of FoxO6 in HCT116 and SW480 were significantly higher than those in FHC (both P<0.05). Knockdown of FoxO6 in HCT116 and SW480 cells decreased the mRNA and protein expressions of FoxO6 (both P<0.05), the cell proliferation ability (absorbances were 0.26±0.07 and 0.27±0.06, both P<0.05), cell invasion ability (the invaded cell numbers were 42.3±3.3 and 45.7±4.1, both P<0.05), and the mRNA and protein expressions of c-Myc, while increased the mRNA and protein expressions of p21 (both P<0.01). Overexpression of Myc in FoxO6 silenced HCT116 and SW480 cells decreased the expression of p21, while increased the cell proliferation ability (absorbances were 0.54±0.09 and 0.58±0.07, both P<0.01) and invasion ability (the invaded cell numbers were 79.2±5.9 and 80.5±6.4, both P<0.01). On the 25th day after cell inoculation in nude mice, the tumor volume of LV-FoxO6 group was (190.6±36.2) mm(3), significantly lower than (437.8.6±69.2) mm(3) of LV-NC group (P<0.05). Conclusion: FoxO6 promotes the proliferation and invasion of colorectal cancer cells through facilitating c-Myc mediated p21 expression inhibition.

[Periostin regulated by let-7/miR-98 family mediates the apoptosis and epithelial-mesenchymal transition of colon cancer].

Objective: To observe the expressions of periostin (Postn) in colon cancer tissues and cells, and to investigate its biological effect and mechanism in colon cancer cells. Methods: Real-time quantitative polymerase chain reaction (RT-qPCR) and western blot were used to detect the expressions of Postn, let-7a and miR-98 in 20 pairs of colon cancer tissues and adjacent normal tissues, colon cancer cell lines including SW480, HT-29, HCT-116 and human normal colon epithelial cell NCM460. Small interfering RNAs (siRNAs) of Postn, pcDNA3.1-Postn plasmids, let-7a mimic and its negative control let-7a mimic-NC, miR-98 mimic and its negative control miR-98 mimic-NC were transfected into HCT-116 cells. 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT) was used to detect cell viability. Flow cytometry was used to detect cell apoptosis. Luciferase reporter gene assay was used to determine the targeting relationship between miRNAs and Postn. Results: Compared with adjacent normal tissues, Postn expression was up-regulated (P<0.05) while let-7a/miR-98 expression was down-regulated (P<0.05) in colon cancer tissues. Compared with NCM460 cells, Postn expression was up-regulated (P<0.05) while let-7a/miR-98 expression was down-regulated (P<0.05) in SW480, HT-29 and HCT-116 cells. In colon cancer tissues, the expression of Postn was negatively correlated with the expressions of let-7a and miR-98 (r=-0.69, P<0.001; r=-0.80, P<0.001). Inhibition of Postn in vitro reduced the viability of HCT-116 cells [(53.73±7.63)%, P<0.05], increased the apoptotic rate [(22.88±3.40)%, P<0.05], enhanced the expression of epithelial-mesenchymal transition (EMT) marker E-cadherin (2.44±0.39, P<0.05), while down-regulated the expressions of N-cadherin and Vimentin (0.44±0.07 and 0.38±0.06, P<0.05). Overexpression of Postn in vitro enhanced the cell viability of HCT-116 cells [(134.41±8.82) %, P<0.05], decreased the expression of E-cadherin (0.55±0.09, P<0.05), increased the expressions of N-cadherin and Vimentin (2.93±0.42 and 2.24±0.34, P<0.05), but had no effect on the apoptotic rate (P>0.05). Overexpression of let-7a or miR-98 partially reversed the biological effects of Postn overexpression in colon cancer cells, which implicated that Postn was a target gene of let-7a/miR-98. Conclusions: Postn is a cancer-promoting molecule of colon cancer, and inhibition of Postn expression can increase the apoptotic rate of colon cancer cells and repress EMT. Postn expression and function is regulated by let-7a/miR-98.

[The expression and functional mechanism of long non-coding RNA LINC00339 in colorectal cancer].

Objective: To investigate the expression of long non-coding RNA LINC00339 in colorectal cancer patients and its effect and mechanism on proliferation and apoptosis of colorectal cancer cells. Methods: A retrospective analysis of 158 pathology-confirmed colorectal cancer patients, who were enrolled from August 2015 to January 2017, was performed. LINC00339 expression in colorectal cancer tissues and adjacent colorectal sampleswas detected by Real-time PCR. The correlation between LINC00339 expression and clinicopathological features as well as the relationship between LINC00339 and microRNA (miR)-218 expression was assayed. The interaction between LINC00339 and miR-218 was further confirmed by dual luciferase report system. Downregulation of LINC00339 was performed by siRNA interference technology in LoVo and HCT116 cells. Real-time PCR was used to detect miR-218 expression. 3-(4,5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) analysis was carried out to examine cell viability. Flow cytometry was used to determine cell apoptosis. Additionally, LINC00339 siRNA and miR-218 antagomirs (anti-miR-218) were co-transfected into LoVo and HCT116 cells, and then cell viability and apoptosis were detected. Results: LINC00339 expression was significantly increased in colorectal cancer tissues compared with adjacent colorectal tissues (4.69±1.52 vs 1.02±0.38, P<0.05). LINC00339 expression was not related to the age and gender of patients (P>0.05), but was associated with TNM stage, lymphatic metastasis, tumor maximum diameters, and differentiation degree (all P<0.05). LINC00339 expression was negatively correlated with miR-218 expression in colorectal cancer tissues (P<0.05). miR-218 mimics remarkably suppressed the fluorescence intensity of wild-type LINC00339 plasmid (P=0.001), but did not affect the fluorescence intensity of the mutant ones(P=0.88). Knockdown of LINC00339 remarkably inhibited proliferation, but promoted apoptosis of LoVo and HCT116 cells (all P<0.05). Compared with cells transfected with LINC00339 siRNA only, downregulation of miR-218 elevated proliferation and decreased apoptosis of LoVoand HCT116 cells. Conclusions: LINC00339 expression is upregulated in colorectal cancer tissues and correlated with patients' clinicopathological features. LINC00339 promotes proliferation, and suppresses apoptosis of colorectal cancer cells via downregulating miR-218.

Epidemiological features and spatio-temporal clusters of hand-foot-mouth disease at town level in Fuyang, Anhui Province, China (2008-2013).

Hand-foot-mouth disease (HFMD) is a frequently occurring epidemic and has been an important cause of childhood mortality in China. Given the disease's significant impact nationwide, the epidemiological characteristics and spatio-temporal clusters in Fuyang from 2008 to 2013 were analysed in this study. The disease exhibits strong seasonality with a rising incidence. Of the reported HFMD cases, 63·7% were male and 95·2% were preschool children living at home. The onset of HFMD is age-dependent and exhibits a 12-month periodicity, with 12-, 24- and 36-month-old children being the most frequently affected groups. Across the first 60 months of life, children born in April [relative risk (RR) 8·18], May (RR 9·79) and June (RR 8·21) exhibited an elevated infection risk of HFMD relative to January-born children; the relative risk compared with the reference (January-born) group was highest for children aged 24 months born in May (RR 34·85). Of laboratory-confirmed cases, enterovirus 71 (EV71), coxsackie A16 (Cox A16) and other enteroviruses accounted for 60·1%, 7·1% and 32·8%, respectively. Spatio-temporal analysis identified one most likely cluster and several secondary clusters each year. The centre of the most likely cluster was found in different regions in Fuyang. Implications of our findings for current and future public health interventions are discussed.

Long-term efficacy of a rural community-based integrated intervention for prevention and management of chronic obstructive pulmonary disease: a cluster randomized controlled trial in China's rural areas

This study aimed to assess the efficacy of a rural community-based integrated intervention for early prevention and management of chronic obstructive pulmonary disease (COPD) in China. This 18-year cluster-randomized controlled trial encompassing 15 villages included 1008 patients (454 men and 40 women in the intervention group [mean age, 54 ± 10 years]; 482 men and 32 women in the control group [mean age, 53 ± 10 years]) with confirmed COPD or at risk for COPD. Villages were randomly assigned to the intervention or the control group, and study participants residing within the villages received treatment accordingly. Intervention group patients took part in a program that included systematic health education, smoking cessation counseling, and education on management of COPD. Control group patients received usual care. The groups were compared after 18 years regarding the incidence of COPD, decline in lung function, and mortality of COPD. COPD incidence was lower in the intervention group than in the control group (10% vs 16%, <0.05). A decline in lung function was also significantly delayed in the intervention group compared to the control group of COPD and high-risk patients. The intervention group showed significant improvement in smoking cessation compared with the control group, and smokers in the intervention group had lower smoking indices than in the control group (350 vs 450, <0.05). The intervention group also had a significantly lower cumulative COPD-related death rate than the control group (37% vs 47%, <0.05). A rural community-based integrated intervention is effective in reducing the incidence of COPD among those at risk, delaying a decline in lung function in COPD patients and those at risk, and reducing mortality of COPD.

MFG-E8, a clearance glycoprotein of apoptotic cells, as a new marker of disease severity in chronic obstructive pulmonary disease

Milk fat globule epidermal growth factor 8 (MFG-E8) is an opsonin involved in the phagocytosis of apoptotic cells. In patients with chronic obstructive pulmonary disease (COPD), apoptotic cell clearance is defective. However, whether aberrant MFG-E8 expression is involved in this defect is unknown. In this study, we examined the expression of MFG-E8 in COPD patients. MFG-E8, interleukin (IL)-1β and transforming growth factor (TGF)-β levels were measured in the plasma of 96 COPD patients (93 males, 3 females; age range: 62.12±10.39) and 87 age-matched healthy controls (85 males, 2 females; age range: 64.81±10.11 years) using an enzyme-linked immunosorbent assay. Compared with controls, COPD patients had a significantly lower plasma MFG-E8 levels (P<0.01) and significantly higher plasma TGF-β levels (P=0.002), whereas there was no difference in plasma IL-1β levels between the two groups. Moreover, plasma MFG-E8 levels decreased progressively between Global Initiative for Chronic Obstructive Lung Disease (GOLD) I and GOLD IV stage COPD. Multiple regression analysis showed that the forced expiratory volume in 1 s (FEV1 % predicted) and smoking habit were powerful predictors of MFG-E8 in COPD (P<0.01 and P=0.026, respectively). MFG-E8 was positively associated with the FEV1 % predicted and negatively associated with smoking habit. The area under the receiver operating characteristic curve was 0.874 (95% confidence interval: 0.798-0.95; P<0.01). Our findings demonstrated the utility of MFG-E8 as a marker of disease severity in COPD and that cigarette smoke impaired MFG-E8 expression in these patients.

MFG-E8, a clearance glycoprotein of apoptotic cells, as a new marker of disease severity in chronic obstructive pulmonary disease.

Milk fat globule epidermal growth factor 8 (MFG-E8) is an opsonin involved in the phagocytosis of apoptotic cells. In patients with chronic obstructive pulmonary disease (COPD), apoptotic cell clearance is defective. However, whether aberrant MFG-E8 expression is involved in this defect is unknown. In this study, we examined the expression of MFG-E8 in COPD patients. MFG-E8, interleukin (IL)-1ß and transforming growth factor (TGF)-ß levels were measured in the plasma of 96 COPD patients (93 males, 3 females; age range: 62.12±10.39) and 87 age-matched healthy controls (85 males, 2 females; age range: 64.81±10.11 years) using an enzyme-linked immunosorbent assay. Compared with controls, COPD patients had a significantly lower plasma MFG-E8 levels (P<0.01) and significantly higher plasma TGF-ß levels (P=0.002), whereas there was no difference in plasma IL-1ß levels between the two groups. Moreover, plasma MFG-E8 levels decreased progressively between Global Initiative for Chronic Obstructive Lung Disease (GOLD) I and GOLD IV stage COPD. Multiple regression analysis showed that the forced expiratory volume in 1 s (FEV1 % predicted) and smoking habit were powerful predictors of MFG-E8 in COPD (P<0.01 and P=0.026, respectively). MFG-E8 was positively associated with the FEV1 % predicted and negatively associated with smoking habit. The area under the receiver operating characteristic curve was 0.874 (95% confidence interval: 0.798-0.95; P<0.01). Our findings demonstrated the utility of MFG-E8 as a marker of disease severity in COPD and that cigarette smoke impaired MFG-E8 expression in these patients.

Long-term efficacy of a rural community-based integrated intervention for prevention and management of chronic obstructive pulmonary disease: a cluster randomized controlled trial in China's rural areas.

This study aimed to assess the efficacy of a rural community-based integrated intervention for early prevention and management of chronic obstructive pulmonary disease (COPD) in China. This 18-year cluster-randomized controlled trial encompassing 15 villages included 1008 patients (454 men and 40 women in the intervention group [mean age, 54 ± 10 years]; 482 men and 32 women in the control group [mean age, 53 ± 10 years]) with confirmed COPD or at risk for COPD. Villages were randomly assigned to the intervention or the control group, and study participants residing within the villages received treatment accordingly. Intervention group patients took part in a program that included systematic health education, smoking cessation counseling, and education on management of COPD. Control group patients received usual care. The groups were compared after 18 years regarding the incidence of COPD, decline in lung function, and mortality of COPD. COPD incidence was lower in the intervention group than in the control group (10% vs 16%, <0.05). A decline in lung function was also significantly delayed in the intervention group compared to the control group of COPD and high-risk patients. The intervention group showed significant improvement in smoking cessation compared with the control group, and smokers in the intervention group had lower smoking indices than in the control group (350 vs 450, <0.05). The intervention group also had a significantly lower cumulative COPD-related death rate than the control group (37% vs 47%, <0.05). A rural community-based integrated intervention is effective in reducing the incidence of COPD among those at risk, delaying a decline in lung function in COPD patients and those at risk, and reducing mortality of COPD.

Orthotopic liver transplantation for incurable alveolar echinococcosis: report of five cases from west China.

Alveolar echinococcosis of the liver, caused by the larval stage of Echinococcus multilocularis, has the characteristics of a slow-growing liver cancer. The aim of the present work was to report a series of patients who received orthotopic liver transplantation (OLT) for life-threatening disease. Our article summarizes the medical history, diagnosis, treatment, and prognosis of five patients who received OLT between 2001 and 2002. Most patients had a long history of symptomatic disease (iterative cholangitis, obstructive jaundice) and repeated abdominal surgery. One patient died during the hospitalization mostly related to bacterial infection and multiple organ failure. Another accidental death happened 3 months later from heart failure. Three patients are alive in good condition verifying that OLT is a feasible option for these end-stage cases. In general, combination therapy-chemotherapy, interventional therapy, radical surgery or/and OLT at an early stage-is proposed in advanced cases of which OLT has clearly played a vital role. Despite major technical difficulties, OLT for incurable disease is feasible. Specific management is needed to improve the results: earlier decision for OLT in symptomatic disease, routine pre- and post-transplant therapy, reduced immunosuppression, and regular follow-up.

Tumorigenicity of racemic and optically pure bay region diol epoxides and other derivatives of the nitrogen heterocycle dibenz[a,h]acridine on mouse skin.

CD-1 female mice were initiated with a single topical application of 500 nmol dibenz[a,h]acridine (DB[a,h]Acr), its racemic trans-1,2-, 3,4-, 8,9- and 10,11-dihydrodiols, racemic DB[a,h]Acr 3,4-diol 1,2-epoxide-1 and -2 or racemic DB[a,h]Acr 10,11-diol 8,9-epoxide-1 and -2, where the benzylic hydroxyl group is either cis (isomer 1) or trans (isomer 2) to the epoxide oxygen. The mice were subsequently treated twice weekly with 12-O-tetradecanoylphorbol 13-acetate for 25 weeks. High tumorigenicity was observed only for DB[a,h]Acr, its 10,11-dihydrodiol and DB[a,h]Acr 10,11-diol 8,9-epoxide-2 (3.3, 1.2 and 1.6 tumors/mouse, respectively). The tumor-initiating activity of a 50 nmol dose of DB[a,h]Acr and the optically active (+)- and (-)-enantiomers of DB[a,h]Acr 10,11-dihydrodiol and of the optically active DB[a,h]Acr 10,11-diol 8,9-epoxide-1 and -2 were also studied. Only DB[a,h]Acr, (-)-DB[a,h]Acr (10R,11R)-dihydrodiol and the bay region (+)-(8R,9S,10S,11R)-diol epoxide-2 were highly active (1.6, 1.7 and 2.4 tumors/mouse, respectively). These results are consistent with previous studies which showed that the corresponding bay region RSSR diol epoxides of benzo[a]pyrene, benz[a]anthracene, chrysene and benzo[c]phenanthrene as well as the aza-polycyclic dibenz[c,h]acridine are the most tumorigenic isomers.

Stimulatory effect of oral administration of green tea or caffeine on ultraviolet light-induced increases in epidermal wild-type p53, p21(WAF1/CIP1), and apoptotic sunburn cells in SKH-1 mice.

Pretreatment of SKH-1 mice with p.o.-administered 0.6% green tea (6 mg of lyophilized tea solids/ml) or 0.044% caffeine (0.44 mg/ml; concentration present in 0.6% green tea) for 2 weeks enhanced UV-induced increases in the number of p53-positive cells, p21(WAF1/CIP1)-positive cells, and apoptotic sunburn cells in the epidermis. These effects of p.o.-administered green tea or caffeine on early adaptive responses to UV provide the first demonstration of in vivo up-regulation of a tumor suppressor gene by a chemopreventive agent. The stimulatory effect of green tea and caffeine on UV-induced increases in the number of p53-positive cells, p21(WAF1/CIP1)-positive cells, and apoptotic sunburn cells may play a role in the inhibitory effects of tea and caffeine on UV-induced carcinogenesis.

Anti-tumor and anti-carcinogenic activities of triterpenoid, beta-boswellic acid.

Boswellin (BE), a methanol extract of the gum resin exudate of Boswellia serrata, contains naturally occurring triterpenoids, beta-boswellic acid and its structural related derivatives, has been used as a traditional medicine for the treatment of inflammatory and arthritic diseases. Topical application of BE to the backs of mice markedly inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced increases in skin inflammation, epidermal proliferation, the number of epidermal cell layers, and tumor promotion in 7,12-dimethylbenz[a]anthracene (DMBA)-initiated mice. Feeding 0.2% of BE in the diet to CF-1 mice for 10-24 weeks reduced the accumulation of parametrial fat pad weight under the abdomen, and inhibited azoxymethane (AOM)-induced formation of aberrant crypt foci (ACF) by 46%. Addition of pure beta-boswellic acid, 3-O-acetyl-beta-boswellic acid, 11-keto-beta-boswellic acid or 3-O-acetyl-11-keto-beta-boswellic acid to human leukemia HL-60 cell culture inhibited DNA synthesis in HL-60 cells in a dose-dependent manner with IC50 values ranging from 0.6 to 7.1 microM. These results indicate that beta-boswellic acid and its derivatives (the major constituents of Boswellin) have anti-carcinogenic, anti-tumor, and anti-hyperlipidemic activities.

Dose-dependent mutation profile in the c-Ha-ras proto-oncogene of skin tumors in mice initiated with benzo[a]pyrene.

Female CD-1 mice were treated topically with a low (25-50 nmol) or high (800 nmol) dose of benzo[a]pyrene (BP) or acetone vehicle, followed by 5 nmol 12-O-tetradecanoylphorbol 13-acetate (TPA) twice a week for 26 weeks. Selective UV radiation fractionation followed by PCR methods were used to analyze histologically defined subsets of cells (approximately 100-200 cells) on formalin-fixed, paraffin-embedded and H&E stained microscope sections. DNA samples from normal-appearing, hyperplastic or tumor regions from the skin of animals from each treatment group were isolated and amplified by PCR with c-Ha-ras-specific primers. Single-strand conformation polymorphism (SSCP) analyses were performed on both exon 1 and 2 products from each sample. DNA extracted from each aberrant band of SSCP analyses was amplified by PCR for further sequence analysis. The data indicate that c-Ha-ras mutations can be detected in normal-looking and hyperplastic epidermal cells as well as in tumor cells obtained from mice initiated with BP and promoted with TPA. The frequencies of c-Ha-ras mutations for normal-looking, hyperplastic and tumor samples were 3/20 (15%), 8/17 (47%) and 58/68 (85%), respectively, for the low dose group and 8/18 (44%), 10/20 (50%) and 64/86 (74%), respectively, for the high dose group. These observations indicate that there were no dose dependencies in the mutation frequencies for normal-looking, hyperplastic and tumor samples. For combined high dose and low dose samples, differences in mutation frequencies of the c-Ha-ras gene between the normal-looking, hyperplastic and tumor samples were highly significant (P < 0.0001, Fisher's exact test). All mutations detected were located at codons 12, 13 and 61 of the c-Ha-ras gene. With the numbers in parentheses indicating the nucleotide position in the coding sequence of the c-Ha-ras proto-oncogene, the distributions of mutations for G-->A (35), G-->T (35), G-->C (37), G-->T (38), C-->A (181), A-->T (182) and A-->G (182) in the low dose tumors were 5, 2, 11, 74, 0, 7 and 2%, respectively, and the distribution of mutations in tumors from animals treated with a high dose of BP were 3, 7, 13, 61, 15, 1 and 0%, respectively. Differences in the global mutation spectra (site and kind of all mutations) for the c-Ha-ras gene between the high and low dose group tumors were statistically significant (P < 0.004, Fisher's exact test) and the major difference between these two groups was C-->A (181) base substitutions. In summary, our data indicate that: (i) 79% of the BP/TPA skin tumors in CD-1 mice had c-Ha-ras mutations for the combined data for high dose and low dose tumors; (ii) the major mutations detected in BP/TPA skin tumors were G-->T transversions; (iii) the global mutation profile in the c-Ha-ras proto-oncogene in skin tumors obtained after initiation with a low dose of BP was different from that obtained after initiation with a high dose of BP.

Effects of oral administration of tea, decaffeinated tea, and caffeine on the formation and growth of tumors in high-risk SKH-1 mice previously treated with ultraviolet B light.

Treatment of SKH-1 mice with ultraviolet B light (UV-B, 30 mJ/cm2) twice a week for 22-23 weeks resulted in tumor-free animals with a high risk of developing malignant and nonmalignant tumors during the next several months in the absence of further UV-B treatment (high-risk mice). In three separate experiments, oral administration of green tea or black tea (4-6 mg tea solids/ml) as the sole source of drinking fluid for 18-23 weeks to these high-risk mice inhibited the formation and decreased the size of nonmalignant squamous cell papillomas and keratoacanthomas as well as the formation and size of malignant squamous cell carcinomas. In one experiment all these inhibitory effects of tea were statistically significant, whereas in the two other experiments many but not all of the inhibitory effects of tea were statistically significant. The decaffeinated teas were inactive or less effective inhibitors of tumor formation than the regular teas, and adding caffeine back to the decaffeinated teas restored biological activity. Oral administration of caffeine alone (0.44 mg/ml) as the sole source of drinking fluid for 18-23 weeks inhibited the formation of nonmalignant and malignant tumors, and this treatment also decreased tumor size in these high-risk mice.

Effect of dietary curcumin and dibenzoylmethane on formation of 7,12-dimethylbenz[a]anthracene-induced mammary tumors and lymphomas/leukemias in Sencar mice.

Female Sencar mice (6 weeks old) were administered 1 mg of 7,12-dimethylbenz[a]anthracene (DMBA) by oral gavage once a week for 5 weeks. At 20 weeks after the first dose of DMBA, 68% of mice developed mammary tumors (the average 1.08 tumors per mouse) and 45% had lymphomas/leukemias. Feeding 1% dibenzoylmethane (DBM) in AIN 76A diet, starting at 2 weeks before the first dose of DMBA and continuing until the end of the experiment, inhibited both the multiplicity and incidence of DMBA-induced mammary tumor by 97%. The incidence of lymphomas/leukemias was completely inhibited by 1% DBM diet. In contrast, feeding 2% curcumin diet had little or no effect on the incidence of mammary tumors, and the incidence of lymphomas/leukemias was reduced by 53%.

Inhibitory effect of black tea on the growth of established skin tumors in mice: effects on tumor size, apoptosis, mitosis and bromodeoxyuridine incorporation into DNA.

Female CD-1 mice were initiated with a single topical application of 7,12-dimethylbenz[a]anthracene and promoted with 12-O-tetradecanoylphorbol-13-acetate. Mice with established papillomas were then treated with black tea or decaffeinated black tea (approximately 4 mg tea solids/ml) as the sole source of drinking fluid for 11-15 weeks. In four separate experiments, oral administration of black tea inhibited the growth of papillomas (increase in tumor volume/mouse) by an average of 35%, 37%, 41% and 48%, respectively. Studies with decaffeinated black tea gave inconsistent results. In one experiment, administration of decaffeinated black tea inhibited papilloma growth (increase in tumor volume/mouse) by 27%, but in two additional experiments papilloma growth was stimulated by 14% and 193%, respectively. In a separate experiment, skin tumors were generated by treating SKH-1 female mice with ultraviolet B light (UVB; 30 mJ/cm2) twice weekly for 22 weeks, after which UVB administration was stopped. Tumors were allowed to develop during the following 13 weeks, and tumor-bearing mice were then treated with black tea (6 mg/ml tea solids) as the drinking fluid for 11 weeks. In this experiment, tumor growth (increase in tumor volume/mouse) was inhibited by 70%. Histological examination revealed that tea-treated mice had a 58% decrease in the number of nonmalignant tumors (primarily keratoacanthomas)/mouse and a 54% decrease in the number of squamous cell carcinomas/mouse. In addition, administration of black tea decreased the volume per tumor by 60% for nonmalignant tumors and by 84% for carcinomas. Mechanistic studies with tumors from these mice revealed that administration of black tea decreased the bromodeoxyuridine labeling index in squamous cell papillomas, keratoacanthomas and squamous cell carcinomas by 56%, 45% and 35%, respectively, and the apoptosis index was increased by 44%, 100% and 95%, respectively. Administration of black tea decreased the mitotic index in keratoacanthomas and squamous cell carcinomas by 42% and 16%, respectively. The results indicate that oral administration of black tea to tumor-bearing mice inhibited proliferation and enhanced apoptosis in nonmalignant and malignant skin tumors.