Omega-3 fatty acids reduce obesity-induced tumor progression independent of GPR120 in a mouse model of postmenopausal breast cancer.

Obesity and inflammation are both risk factors for a variety of cancers, including breast cancer in postmenopausal women. Intake of omega-3 polyunsaturated fatty acids (ω-3 PUFAs) decreases the risk of breast cancer, and also reduces obesity-associated inflammation and insulin resistance, but whether the two effects are related is currently unknown. We tested this hypothesis in a postmenopausal breast cancer model using ovariectomized, immune-competent female mice orthotopically injected with Py230 mammary tumor cells. Obesity, whether triggered genetically or by high-fat diet (HFD) feeding, increased inflammation in the mammary fat pad and promoted mammary tumorigenesis. The presence of tumor cells in the mammary fat pad further enhanced the local inflammatory milieu. Tumor necrosis factor-alpha (TNF-α) was the most highly upregulated cytokine in the obese mammary fat pad, and we observed that TNF-α dose-dependently stimulated Py230 cell growth in vitro. An ω-3 PUFA-enriched HFD (referred to as fish oil diet, FOD) reduced inflammation in the obese mammary fat pad in the absence of tumor cells and inhibited Py230 tumor growth in vivo. Although some anti-inflammatory effects of ω-3 PUFAs were previously shown to be mediated by the G-protein-coupled receptor 120 (GPR120), the FOD reduced Py230 tumor burden in GPR120-deficient mice to a similar degree as observed in wild-type mice, indicating that the effect of FOD to reduce tumor growth does not require GPR120 in the host mouse. Instead, in vitro studies demonstrated that ω-3 PUFAs act directly on tumor cells to activate c-Jun N-terminal kinase, inhibit proliferation and induce apoptosis. Our results show that obesity promotes mammary tumor progression in this model of postmenopausal breast cancer and that ω-3 PUFAs, independent of GPR120, inhibit mammary tumor progression in obese mice.

Prognostic implication of mucinous histology in colorectal cancer patients treated with adjuvant FOLFOX chemotherapy.

BACKGROUND: There have been controversies in prognostic impact of mucinous histology on colorectal cancer, and its implication in patients treated with adjuvant 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX) is unclear. METHODS: Stage II and III colorectal cancer patients who underwent curative resection followed by adjuvant FOLFOX were included. Patients were grouped according to the mucinous content: >50%, mucinous adenocarcinoma (MAC); <50%, adenocarcinoma with intermediated mucinous component (AIM); and without any mucinous component, non-MAC (NMA). Clinicopathological features and disease-free survival (DFS) were compared. RESULTS: Among a total of 521 patients, 27 patients (5.2%) had MAC, 41 patients (7.9%) had AIM, and 453 patients (86.9%) had NMA. Mucinous adenocarcinoma and AIM had higher frequency of proximal location and microsatellite instability, but lower frequency of angiolymphatic invasion. Disease-free survival was significantly worse in the MAC compared with NMA (3-year DFS 57% and 86%, respectively; P<0.001) and AIM (3-year DFS 87%, P=0.01 vs MAC). Multivariate analysis revealed MAC as an independent negative prognostic factor of DFS (adjusted hazard ratio 7.96, 95% confidence interval 3.76-16.8). CONCLUSION: Adenocarcinoma with intermediated mucinous component and MAC have distinct clinicopathological features compared with NMA. Mucinous adenocarcinoma has an adverse prognostic impact on stage II or III colorectal cancer treated with adjuvant FOLFOX.

Postoperative chemoradiotherapy for gallbladder cancer.

PURPOSE: The goal of this work was to analyze the outcome of adjuvant chemoradiotherapy for patients with gallbladder cancer who underwent surgical resection and to identify the prognostic factors for these patients. PATIENTS AND METHODS: Between August 1989 and November 2006, 47 patients with gallbladder cancer underwent surgical resection followed by adjuvant radiotherapy. There were 21 males and 26 females, and median age was 60 years (range 44-75 years). Postoperative radiotherapy was delivered to the tumor bed and regional lymph nodes up to 40-50 Gy at 2 Gy/fraction; 41 patients also received intravenous 5-fluorouracil as a radiosensitizer. Median follow-up duration was 48 months for survivors. RESULTS: There were 2 isolated locoregional recurrences, 14 isolated distant metastases, and 7 combined locoregional and distant relapses. The 5-year overall survival rate was 43.7%. According to the extent of resection, the 5-year overall survival rates were 52.8%, 20.0%, and 0% in R0-, R1-, and R2-resected patients, respectively (p = 0.0038). On multivariate analysis incorporating extent of resection, T stage, N stage, performance of lymph node dissection, and histologic differentiation, extent of resection was the only prognostic factor associated with overall survival (p = 0.0075). Among the 37 patients with R0 resection, there was no difference of 5-year overall survival rates in patients with N0, N1, and Nx diseases (46.2%, 60.0%, and 44.4%, respectively, p = 0.6246). As for significant treatment-related morbidity, there was only 1 patient with grade 4 gastric ulcer. CONCLUSION: Adjuvant chemoradiotherapy after R0 resection can achieve a good long-term survival rate in gallbladder cancer patients, even in those with lymph node metastases, and may play a role for patients who underwent R0 resection of primary tumor without lymph node dissection.

Granzyme A activates an endoplasmic reticulum-associated caspase-independent nuclease to induce single-stranded DNA nicks.

The cytotoxic T lymphocyte protease granzyme A (GzmA) initiates a novel caspase-independent cell death pathway characterized by single-stranded DNA nicking. The previously identified GzmA substrate SET is in a multimeric 270-420-kDa endoplasmic reticulum-associated complex that also contains the tumor suppressor protein pp32. GzmA cleaved the nucleosome assembly protein SET after Lys(176) and disrupted its nucleosome assembly activity. The purified SET complex required only GzmA to reconstitute single-stranded DNA nicking in isolated nuclei. DNA nicking occurred independently of caspase activation. The SET complex contains a 25-kDa Mg(2+)-dependent nuclease that degrades calf thymus DNA and plasmid DNA. Thus, GzmA activates a DNase (GzmA-activated DNase) within the SET complex to produce a novel form of DNA damage during cytotoxic T lymphocyte-mediated death.