Clinical significance of SQSTM1/P62 and nuclear factor-κB expression in pancreatic carcinoma.

BACKGROUND: Overexpression of SQSTM1 (sequestosome 1, P62) and nuclear factor-κB (NF-κB) plays an important role in the invasion and metastasis of a variety of malignant tumors. AIM: To explore the expression of P62 and NF-κB in pancreatic cancer and their relationship with clinicopathological features. METHODS: The expression levels of P62 and NF-κB were analyzed by immunohistochemistry with a tissue chip containing 40 cases of human pancreatic carcinoma. Then we analyzed the correlation among P62 expression, phospho-P65 expression, and clinicopathological features of pancreatic carcinoma samples. RESULTS: P62 expression was mainly observed in the cytoplasm of pancreatic carcinoma cells. Phosphorylated P65 (phospho-P65) was mainly expressed in the nucleus and cytoplasm of pancreatic carcinoma cells. There was a significant difference in P62 expression among T stages. And a significant difference in phosphor-P65 expression among pathology types was noted. In the cases with strongly positive P62 expression, significant differences were found in age. And there were significant differences in T stage and tumor-node-metastasis stage in the cases with strongly positive phosphor-P65 expression. CONCLUSION: In pancreatic carcinoma, P62 expression is significantly correlated with T stage. It may be a valuable malignant indicator for human pancreatic carcinoma.

Interleukin-1 receptor antagonist enhances chemosensitivity to fluorouracil in treatment of Kras mutant colon cancer.

BACKGROUND: Kras mutant colon cancer shows abnormal activation of the nuclear factor kappa-B (NF-κB) pathway, resulting in the proliferation of tumor cells. Treatment with fluorouracil (5-FU) might not achieve the expected inhibition of proliferation of malignant cells based on the fluorouracil-induced activation of the NF-κB pathway. AIM: To detect whether interleukin (IL)-1 receptor antagonist (IL-1RA) could increase the chemosensitivity to 5-FU by decreasing the activation of the NF-κB pathway and reducing the proliferation of colon cancer cells. METHODS: Western blot analysis was performed to detect the persistent activation of the NF-κB pathway in colon cancer cell lines. Reverse transcription-polymerase chain reaction was used to detect the IL-1RA-reduced expression levels of IL-6, IL-8, IL-17, IL-21 and TLR4 in colon cancer cell lines. We used a xenograft nude mouse model to demonstrate the downregulation of the NF-κB pathway by blocking the NF-κB-regulated IL-1α feedforward loop, which could increase the efficacy of chemotherapeutic agents in inhibiting tumor cell growth. RESULTS: IL-1 receptor antagonist could decrease the expression of IL-1α and IL-1ß and downregulate the activity of the NF-κB pathway in Kras mutant colon cancer cells. Treatment with 5-FU combined with IL-1RA could increase the chemosensitivity of the SW620 cell line, and decreased expression of the TAK1/NF-κB and MEK pathways resulted in limited proliferation in the SW620 cell line. CONCLUSION: Adjuvant chemotherapy with IL-1RA and 5-FU has a stronger effect than single chemotherapeutic drugs. IL-1RA combined with fluorouracil could be a potential neoadjuvant chemotherapy in the clinic.

Hypoxia preconditioning protects Ca2+-ATPase activation of intestinal mucosal cells against R/I injury in a rat liver transplantation model.

AIM: To investigate the effect of ischaemia and reperfusion (I/R) injury on the Ca2+-ATPase activation in the intestinal tissue of a rat autologous orthotopic liver transplantation model and to determine if hypoxia preconditioning (HP) therapy induces HIF-1α to protect rat intestinal tissue against I/R injury. METHODS: Rats received non-lethal hypoxic preconditioning therapy to induce HIF-1α expression. We used an autologous orthotopic liver transplantation model to imitate the I/R injury in intestinal tissue. Then, we detected the microstructure changes in small intestinal tissues, Ca2+-ATPase activity, apoptosis, and inflammation within 48 h postoperatively. RESULTS: HIF-1α expression was significantly increased in intestinal tissue at 12 h postoperatively in rats that were exposed to a hypoxic environment for 90 min compared with a non-HP group (HP vs AT, P = 0.0177). Pathological analysis was performed on the intestinal mucosa cells, and the cells in the HP group appeared healthier than the cells in the AT group. The Ca2+-ATPase activity in the small intestinal cells in the AT group was significantly lower after the operation, and the Ca2+-ATPase activity in the HP group recovered faster than that in the AT group at 6 h postoperatively (HP vs AT, P = 0.0106). BCL-2 expression in the HP group was significantly higher than that in the AT group at 12 h postoperatively (HP vs AT P = 0.0010). The expression of the inflammatory factors NO, SOD, IL-6, and TNF-α was significantly lower in the HP group than in the AT group. CONCLUSION: Hypoxia-induced HIF-1α could protect intestinal mucosal cells against mitochondrial damage after I/R injury. HP could improve hypoxia tolerance in small intestinal mucosal cells and increase Ca2+-ATPase activity to reduce the apoptosis of and pathological damage to intestinal cells. HP could be a useful way to promote the earlier recovery of intestinal function after graft procedure.

Regulation of the Nampt-mediated NAD salvage pathway and its therapeutic implications in pancreatic cancer.

Nicotinamide adenine dinucleotide (NAD) is a crucial cofactor for the redox reactions in the metabolic pathways of cancer cells that have elevated aerobic glycolysis (Warburg effect). Cancer cells are reported to rely on NAD recycling and inhibition of the NAD salvage pathway causes metabolic collapse and cell death. However, the underlying regulatory mechanisms and clinical implications for the NAD salvage pathway in pancreatic ductal adenocarcinoma (PDAC) remain unclear. This study showed that the expression of Nampt, the rate-limiting enzyme of the NAD salvage pathway, was significantly increased in PDAC cells and PDAC tissues. Additionally, inhibition of Nampt impaired tumor growth in vitro and tumorigenesis in vivo, which was accompanied by a decreased cellular NAD level and glycolytic activity. Mechanistically, the Nampt expression was independent of Kras and p16 status, but it was directly regulated by miR-206, which was inversely correlated with the expression of Nampt in PDAC tissues. Importantly, pharmacological inhibition of Nampt by its inhibitor, FK866, significantly enhanced the antitumor activity of gemcitabine in PDAC cells and in orthotopic xenograft mouse models. In conclusion, the present study revealed a novel regulatory mechanism for Nampt in PDAC and suggested that Nampt inhibition may override gemcitabine resistance by decreasing the NAD level and suppressing glycolytic activity, warranting further clinical investigation for pancreatic cancer treatment.

Integrin αvß6 and matrix metalloproteinase 9 correlate with survival in gastric cancer.

AIM: To investigate the expression of integrin αvß6 and matrix metalloproteinase 9 (MMP-9), their association with prognostic factors and to assess their predictive role in gastric cancer patients. METHODS: Immunohistochemistry was used to determine the expressions of integrin αvß6 and MMP-9 in 126 specimens from patients with primary gastric carcinoma. Associations between immunohistochemical staining and various clinic pathologic variables of tissue specimens were evaluated by the χ(2) test and Fisher's exact test. Expression correlation of αvß6 and MMP-9 was assessed using bivariate correlation analysis. The patients were followed-up every 3 mo in the first two years and at least every 6 mo afterwards, with a median follow-up of 56 mo (ranging from 2 mo to 94 mo). Four different combinations of αvß6 and MMP-9 levels (that is, both markers positive, both markers negative, αvß6 positive with MMP-9 negative, and αvß6 negative with MMP-9 positive) were evaluated for their relative effect on survival. The difference in survival curves was evaluated with a log-rank test. Survival analysis was conducted using the Kaplan-Meier survival and Cox proportional hazards model analysis. RESULTS: The expressions of integrin αvß6 and MMP-9 were investigated in 126 cases, among which 34.92% were positive for αvß6 expression, and 42.06% for MMP-9 expression. The expression of αvß6 was associated with Lauren type, differentiation, N stage, and TNM stage (the P values were 0.006, 0.038, 0.016, and 0.002, respectively). While MMP-9 expression was associated with differentiation, T stage, N stage, and TNM stage (the P values were 0.039, 0.014, 0.033, and 0.008, respectively). The positive correlation between αvß6 and MMP-9 in gastric cancer was confirmed by a correlation analysis. The Kaplan-Meier survival analysis showed that patients with expression of αvß6 or MMP-9 alone died earlier than those with negative expression and that patients who were both αvß6 and MMP-9 positive had a shorter overall survival than those with the opposite pattern (both αvß6 and MMP-9 negative) (P = 0.000). A Cox model indicated that positive expression of αvß6 and MMP-9, diffuse Lauren type, as well as a senior grade of N stage, M stage, and TNM stage were predictors of a poor prognosis in univariate analysis. Only αvß6 and MMP-9 retained their significance when adjustments were made for other known prognostic factors in multivariate analysis (RR = 2.632, P = 0.003 and RR = 1.813, P = 0.007). CONCLUSION: The expression of αvß6 and MMP-9 are closely correlated, and the combinational pattern of αvß6 and MMP-9 can serve as a more effective prognostic index for gastric cancer patients.

Mechanisms of Overcoming Intrinsic Resistance to Gemcitabine in Pancreatic Ductal Adenocarcinoma through the Redox Modulation.

Pancreatic ductal adenocarcinoma (PDAC) frequently develops therapeutic resistances, which can be divided into extrinsic and intrinsic resistance. The extrinsic resistance that arises from the surrounding dense tumor stroma is much better understood. However, the mechanisms of intrinsic resistance are not well understood. Here, we report that reactive oxygen species (ROS) induced by gemcitabine treatment, a newly discovered cytotoxic activity, served as a probe in our study to reveal the mechanisms of the intrinsic therapeutic resistance. Our results showed that gemcitabine-induced ROS is generated by NOX and through the increase of p22(-phox) expression via NF-κB activation. As a feedback mechanism, nuclear translocation of Nrf2 stimulated the transcription of cytoprotective antioxidant genes, especially genes encoding enzymes that catalyze glutathione (GSH) production to reduce elevated ROS as an intrinsic resistance countermeasure. RNAi-mediated depletion of Nrf2 or addition of ß-phenylethyl isothiocyanate inhibited the ROS detoxification process by reducing GSH levels, which, in turn, increased the efficacy of gemcitabine in vitro and in vivo. Thus, our study suggests that a redox-mediated pathway contributes to the intrinsic resistance of PDAC to gemcitabine and provides a basis for developing strategies to preferentially kill PDAC cells through ROS-mediated mechanism. The combination of gemcitabine and PEITC has a selective cytotoxic effect against pancreatic cancer cells in vivo and could thus prove valuable as a cancer treatment.

Clinical significance of integrin ß6 as a tumor recurrence factor in follicular thyroid carcinoma.

BACKGROUND: Overexpression of integrin ß6 plays an important role in a variety of malignant tumor invasion and metastasis. METHODS: The expression levels of integrin ß6, matrix metalloproteinase (MMP)-2 and MMP-9 were analyzed by immunohistochemistry with human follicular thyroid carcinomas. Then we investigated their correlation with clinical outcomes parameters, relationship, and the survival time. RESULTS: The integrin ß6 staining was expressed in cellular membrane and cytoplasm of follicular thyroid carcinoma cells. The MMP-2 and MMP-9 expressions were mainly found in cellular cytoplasm. In correlation with the clinical outcome parameters of 60 patients, there were significant statistical differences of integrin ß6, MMP-2, and MMP-9 expression levels in different size of tumor. Integrin ß6 and MMP-9 expressions have significant statistical differences in T classifications. MMP-2 and MMP-9 expressions have significant statistical differences in different M classification. Other clinical outcome parameters had no significant statistical differences. CONCLUSION: Integrin ß6 expression correlated significantly with MMP-9 expression, and may be a valuable recurrence indicator for follicular thyroid carcinomas.