Cancer cells are characterized by malignant proliferation and aberrant metabolism and are thereby liable to the depletion of nutrients and accumulation of metabolic waste. To maintain cellular homeostasis, cancer cells are prone to upregulating the canonical autophagy pathway. Here, we identified paroxetine hydrochloride (Paxil) as a late autophagy inhibitor and investigated its killing effect on lung cancer cells and with a xenograft mouse model in vivo. Upregulated LC3-II and p62 expression indicated that Paxil inhibited autophagy. Acid-sensitive dyes (e.g., LysoTracker and AO staining) indicated reduced lysosomal acidity following Paxil treatment; consequently, the maturation of the pH-dependent hydroxylases (e.g., cathepsin B and D) substantially declined. Paxil also induced the fragmentation of mitochondria and further intensified ROS overproduction. Since the autophagy pathway was blocked, ROS rapidly accumulated, which activated JNK and p38 kinase. Such activity promoted the localization of Bax, which led to increased mitochondrial outer membrane permeability. The release of Cytochrome c with the loss of the membrane potential triggered a caspase cascade, ultimately leading to apoptosis. In contrast, the clearance of ROS by its scavenger, NAC, rescued Paxil-induced apoptosis accompanied by reduced p38 and JNK activation. Thus, Paxil blocked the autophagic flux and induced the mitochondria-dependent apoptosis via the ROS-MAPK pathway.

Chemoresistance is a major limiting factor that impairs the outcome of non-small cell lung cancer (NSCLC) chemotherapy. Paclitaxel (Tax) induces protective autophagy in NSCLC cells, leading to the development of drug resistance. We recently identified a new autophagy inhibitor (alpha-hederin) and hypothesized that it may promote the killing effect of Tax on NSCLC cells. We found that alpha-hederin (α-Hed) could block late autophagic flux in NSCLC cells by altering lysosomal pH and inhibiting lysosomal cathepsin D maturation. Combination treatment of α-Hed and Tax synergistically reduced NSCLC cell proliferation and increased NSCLC cell apoptosis compared with treatment with α-Hed or Tax alone. Furthermore, α-Hed plus Tax enhanced the accumulation of intracellular reactive oxygen species (ROS) in NSCLC cells, while the ROS inhibitor N-acetylcysteine reversed the inhibitory effect of the combination treatment. Our findings suggest that α-Hed can increase the killing effect of Tax on NSCLC cells by promoting ROS accumulation, and that combining α-Hed with classical Tax represents a novel strategy for treating NSCLC.

The main mechanistic function of most chemotherapeutic drugs is mediated by inducing mitochondria-dependent apoptosis. Tumor cells usually respond to upregulate autophagy to eliminate impaired mitochondria for survival. Hypothetically, inhibiting autophagy might promote mitochondria-dependent apoptosis, thus enhancing the efficacy of chemotherapeutic therapies. We previously identified N-methylparoxetine (NMP) as an inducer of mitochondrial fragmentation with subsequent apoptosis in non-small cell lung cancer (NSCLC) cells. We discovered that ROS was accumulated in NMP-treated NSCLC cells, followed by c-Jun N-terminal kinase (JNK) and p38 MAP kinase (p38) activation. This was reversed by the application of a reactive oxygen species (ROS) scavenger, N-acetylcysteine (NAC), leading to a reduction in apoptosis. Our data suggested that NMP induced apoptosis in NSCLC cells by activating mitogen-activated protein kinase (MAPK) pathway. We further speculated that the remarkable increase of ROS in NMP-treated NSCLC cells might result from an inhibition of autophagy. Our current data confirmed that NMP blocked autophagy flux at late stage wherein lysosomal acidification was inhibited. Taken together, this study demonstrated that NMP could exert dual apoptotic functions—mitochondria impairment and, concomitantly, autophagy inhibition. NMP-related excessive ROS accumulation induced apoptosis by activating the MAPK pathway in NSCLC cells.

This project achieved a significant improvement in evidence-based practice for the management of non-adherence to fluid-intake restrictions in HD patients. An increase in the number of HD patients found to be adherent to fluid-intake restrictions was reported during this process.

Hepatocellular carcinoma (HCC) is the fifth most common cancer in the world. Ubiquitin-proteasome system has been shown to play a pivotal role in the pathophysiology of HCC and other malignancies. UBE2Q1 is a putative E2 ubiquitin conjugating enzyme, and may be involved in the regulation of cancer-related proteins. In this study, we investigated the expression pattern of UBE2Q1 in HCC cell lines and human HCC specimens, and its potential clinical and biological significance in HCC. Western blot and immunohistochemical analyses revealed that UBE2Q1 was significantly upregulated in HCC tumorous tissues compared with the adjacent noncancerous ones. Next, univariate and multivariate survival analyses were performed to determine the prognostic significance of UBE2Q1 in HCC. The results showed that upregulated expression of UBE2Q1 was positively correlated with high histological grades of HCC and predicted poor prognosis. In addition, the expression of UBE2Q1 was progressively increased in serum-refed HCC cells. UBE2Q1 depletion by small interfering RNA inhibited cell proliferation and led to G1 phase arrest in HepG2 and BEL-7404 cells. Furthermore, we showed that cells transfected with UBE2Q1-targeting siRNA resulted in significant increase in the levels of p53, p21 in HepG2 and BEL-7404 cells. These data imply that UBE2Q1 is upregulated in liver cancer cell lines and tumorous samples and may play a role in the development of HCC.