Limonin inhibits the stemness of cancer stem-like cells derived from colorectal carcinoma cells potentially via blocking STAT3 signaling.

BACKGROUND: Limonin is one of the most abundant active ingredients of Tetradium ruticarpum. It exerts antitumor effects on several kinds of cancer cells. However, whether limonin exerts antitumor effects on colorectal cancer (CRC) cells and cancer stem-like cells (CSCs), a subpopulation responsible for a poor prognosis, is unclear. AIM: To evaluate the effects of limonin on CSCs derived from CRC cells. METHODS: CSCs were collected by culturing CRC cells in serum-free medium. The cytotoxicity of limonin against CSCs and parental cells (PCs) was determined by cholecystokinin octapeptide-8 assay. The effects of limonin on stemness were detected by measuring stemness hallmarks and sphere formation ability. RESULTS: As expected, limonin exerted inhibitory effects on CRC cell behaviors, including cell proliferation, migration, invasion, colony formation and tumor formation in soft agar. A relatively low concentration of limonin decreased the expression stemness hallmarks, including Nanog and ß-catenin, the proportion of aldehyde dehydrogenase 1-positive CSCs, and the sphere formation rate, indicating that limonin inhibits stemness without presenting cytotoxicity. Additionally, limonin treatment inhibited invasion and tumor formation in soft agar and in nude mice. Moreover, limonin treatment significantly inhibited the phosphorylation of STAT3 at Y705 but not S727 and did not affect total STAT3 expression. Inhibition of Nanog and ß-catenin expression and sphere formation by limonin was obviously reversed by pretreatment with 2 µmol/L colievlin. CONCLUSION: Taken together, these results indicate that limonin is a promising compound that targets CSCs and could be used to combat CRC recurrence and metastasis.

Incidence, clinical characteristics, and outcome of interstitial pneumonia in patients with lymphoma.

Interstitial pneumonia (IP) is a lethal complication in lymphoma patients undergoing chemotherapy. A total of 2212 consecutive patients diagnosed with lymphoma between 2009 and 2014 were enrolled in the present study. IP was defined as diffuse pulmonary interstitial infiltrate found on computed tomography scans. IP was observed in 106 patients. Of these, 23 patients were excluded from the study. Finally, 83 patients with IP were included in this study. The incidence of IP was 3.9% (7/287) in Hodgkin lymphoma and 2.4% (76/1925) in non-Hodgkin lymphoma (P = 0.210). The median number of chemotherapy cycles before IP was 3. The median time from the cessation of chemotherapy to IP was 17 days. Eighty-two (98.8%) patients recovered after the treatment with glucocorticoids. Sixty-six (79.5%) patients had a delay in chemotherapy, and 14 (16.9%) patients had premature termination of chemotherapy. Sixty-nine patients were re-treated with chemotherapy after remission from IP, of which 22 (31.9%) experienced IP recurrence. The incidence of IP recurrence was significantly higher in patients re-treated with a similar regimen than in those re-treated with an alternative regimen (65.4 vs. 11.6%, P < 0.001). In a multivariate Cox regression analysis, B symptoms and a history of drug allergies were identified as risk factors for IP. In conclusion, IP is a life-threatening complication in lymphoma patients. Glucocorticoid therapy with continuous monitoring of chest radiographic changes may be a favourable strategy for treating IP. However, IP may recur, especially in patients re-treated with a similar chemotherapy regimen.

PARP1 Val762Ala polymorphism reduces enzymatic activity.

Poly(ADP-ribose) polymerase 1 (PARP1) modifies a variety of nuclear proteins by poly(ADP-ribosyl)ation, and plays diverse roles in molecular and cellular processes. A common PARP1 single nucleotide polymorphism (SNP) at codon 762, resulting in the substitution of alanine (Ala) for valine (Val) in the catalytic domain has been implicated in susceptibility to cancer. To characterize the functional effect of this polymorphism on PARP1, we performed in vitro enzymatic analysis on PARP1-Ala762 and PARP1-Val762. We found that PARP1-Ala762 displayed 57.2% of the activity of PARP1-Val762 for auto-poly(ADP-ribosyl)ation and 61.9% of the activity of PARP1-Val762 for trans-poly(ADP-ribosyl)ation of histone H1. The kinetic characterization revealed that the K(m) of PARP1-Ala762 was increased to a 1.2-fold of the K(m) of PARP1-Val762 for trans-poly(ADP-ribosyl)ation. Thus, the PARP1 Val762Ala polymorphism reduces the enzymatic activity of PARP1 by increasing K(m). This finding suggests that different levels of poly(ADP-ribosyl)ation by PARP1 might aid in understanding the cancer risk of carriers of the PARP1 Val762Ala polymorphism.