Antidepressants synergize with chemotherapy against cancer stem cells

Desmethylclomipramine triggers mitochondrial damage and death in TGF-β-induced mesenchymal type of A549 cells

Lung cancer is the leading cause of cancer deaths, where the metastasis often causes chemodrug resistance and leads to recurrence after treatment. Desmethylclomipramine (DCMI), a bioactive metabolite of clomipramine, shows the therapeutic efficacy with antidepressive agency as well as potential cytostatic effects on lung cancer cells. Here, we demonstrated that DCMI effectively caused transforming growth factor (TGF)-β1-mediated mesenchymal type of A549 cells to undergo mitochondrial death via myeloid cell leukemia-1 (Mcl-1) suppression and activation of truncated Bid (tBid). TGF-β1 induced epithelial mesenchymal transition in A549 cells with the increase of fibronectin and decrease of E-cadherin, the activation of Akt/glycogen synthase kinase-3β (GSK-β)/Mcl-1 axis, and the hypo-responsiveness to cisplatin. DCMI initiated a dose-dependent cytotoxicity on TGF-β1-mediated mesenchymal type of A549 cells through inactivating Akt/GSK-β/Mcl-1 axis, in which mitochondria instability and caspase-9/3 activation also occurred concurrently. Pharmacological inhibition of caspase-8 and cathepsin B partly reversed tBid expression and mitochondrial damage to further attenuate DCMI-mediated cytotoxicity. Additionally, DCMI presented partial therapeutic effects in treating mesenchymal type of A549 tumor bearing nude mice through an acceleration of cancer cell death. Taken together, DCMI exerts antitumor effects via initiating the mechanisms of Akt/GSK-β/Mcl-1 inactivation and cathepsin B/caspase-8-regulated mitochondrial death, which suggests its potential role in mesenchymal type of cancer cell therapy.

Use of Selective Serotonin Reuptake Inhibitors Is Associated with a Lower Risk of Colorectal Cancer among People with Family History

Individuals with a family history of colorectal cancer (CRC) are at a high risk of developing CRC. Preclinical and population-based evidence suggests that selective serotonin reuptake inhibitors (SSRIs) might play a role in preventing CRC. We performed a nationwide cohort study to explore whether the use of SSRIs could reduce CRC risk among individuals with family history. We identified individuals aged 50 and above who had one or more first-degree relatives diagnosed with CRC. A total of 38,617 incident SSRI users were identified and matched with 115,851 non-users, on a ratio of 1:3. The Cox regression model was used to calculate hazard ratios (HRs) and 95% CI confidence intervals (CIs). We found a significant negative association between SSRI use and the risk of CRC (adjusted HR, 0.77; 95% CI, 0.70-0.85). Restricted cubic spline regression showed a non-linear dose-responded relationship between SSRI use and CRC risk. The association was stronger in rectal cancer than colon cancer (adjusted HR, 0.73 vs. 0.79), and more pronounced in advanced-stage CRC than early-stage CRC (adjusted HR, 0.73 vs. 0.80). This population-based cohort study suggests that the use of SSRIs is associated with a reduced risk of CRC among individuals with a family history of CRC.

Ultraconserved long non-coding RNA uc.63 in breast cancer

Transcribed-ultraconserved regions (T-UCRs) are long non-coding RNAs (lncRNA) encoded by a subset of long ultraconserved stretches in the human genome. Recent studies revealed that the expression of several T-UCRs is altered in cancer and growing evidences underline the importance of T-UCRs in oncogenesis, offering also potential new strategies for diagnosis and prognosis. We found that overexpression of one specific T-UCRs named uc.63 is associated with bad outcome in luminal A subtype of breast cancer patients. uc.63 is localized in the third intron of exportin-1 gene (XPO1) and is transcribed in the same orientation of its host gene. Interestingly, silencing of uc.63 induces apoptosis in vitro. However, silencing of host gene XPO1 does not cause the same effect suggesting that the transcription of uc.63 is independent of XPO1. Our results reveal an important role of uc.63 in promoting breast cancer cells survival and offer the prospect to identify a signature associated with poor prognosis.