Gemcitabine promotes autophagy and lysosomal function through ERK- and TFEB-dependent mechanisms

Small non-coding RNAs and pancreatic ductal adenocarcinoma: Linking diagnosis, pathogenesis, drug resistance, and therapeutic potential

This review comprehensively investigates the intricate interplay between small non-coding RNAs (sncRNAs) and pancreatic ductal adenocarcinoma (PDAC), a devastating malignancy with limited therapeutic options. Our analysis reveals the pivotal roles of sncRNAs in various facets of PDAC biology, spanning diagnosis, pathogenesis, drug resistance, and therapeutic strategies. sncRNAs have emerged as promising biomarkers for PDAC, demonstrating distinct expression profiles in diseased tissues. sncRNA differential expression patterns, often detectable in bodily fluids, hold potential for early and minimally invasive diagnostic approaches. Furthermore, sncRNAs exhibit intricate involvement in PDAC pathogenesis, regulating critical cellular processes such as proliferation, apoptosis, and metastasis. Additionally, mechanistic insights into sncRNA-mediated pathogenic pathways illuminate novel therapeutic targets and interventions. A significant focus of this review is dedicated to unraveling sncRNA mechanisms underlying drug resistance in PDAC. Understanding these mechanisms at the molecular level is imperative for devising strategies to overcome drug resistance. Exploring the therapeutic landscape, we discuss the potential of sncRNAs as therapeutic agents themselves as their ability to modulate gene expression with high specificity renders them attractive candidates for targeted therapy. In summary, this review integrates current knowledge on sncRNAs in PDAC, offering a holistic perspective on their diagnostic, pathogenic, and therapeutic relevance. By elucidating the roles of sncRNAs in PDAC biology, this review provides valuable insights for the development of novel diagnostic tools and targeted therapeutic approaches, crucial for improving the prognosis of PDAC patients.

Cell Death and Survival Mechanisms in Cholangiocarcinogenesis

Cholangiocarcinoma (CCA) and other liver cancer subtypes often develop in damaged organs. Physiological agents or extrinsic factors, like toxins, can induce cell death in such tissues, triggering compensatory proliferation and inflammation. Depending on extracellular and intracellular factors, different mechanisms, like apoptosis, necroptosis, ferroptosis, or autophagy, can be triggered. Each of them can lead to protumorigenic or anti-tumorigenic events within a cell or through regulation of the microenvironment. However, the exact role of each cell death mechanism in CCA onset, progression, and treatment is not well known. Here, we summarize current knowledge of different cell death mechanisms in patients with CCA and preclinical CCA research. We discuss cell death-related drugs with relevance to CCA treatment and how they could be used in the future to improve targeted CCA therapy.

Inhibition of autophagy induced by tetrandrine promotes the accumulation of reactive oxygen species and sensitizes efficacy of tetrandrine in pancreatic cancer

Pancreatic cancer, characterized by its poor prognosis, exhibits a marked resistance to conventional chemotherapy and immunotherapy, underscoring the urgent need for more effective treatment modalities. In light of this, the present study is designed to assess the potential antineoplastic efficacy of a combined regimen involving tetrandrine, a plant-derived alkaloid, and autophagy inhibitors in the context of pancreatic cancer. Electron microscopy and immunoblots showed that tetrandrine promoted the formation of autophagosomes and the upregulation of LC3II and the downregulation of p62 expression, indicating that tetrandrine induced autophagy in pancreatic cancer cells. Western blot revealed that tetrandrine inhibited the phosphorylation of AKT and mTOR, as well as the expression of Bcl-2, while upregulating Beclin-1 expression. Moreover, tetrandrine promoted the transcription and protein expression of ATG7. Following the combination of autophagy inhibitors and tetrandrine, the apoptotic rate and cell death significantly increased in pancreatic cancer cells. Consistent results were obtained when ATG7 was silenced. Additionally, tetrandrine induced the generation of ROS, which was involved in the activation of autophagy and apoptosis. Further investigation revealed that upon autophagy inhibition, ROS accumulated in pancreatic cancer cells, resulting in decreased mitochondrial membrane potential and further induction of apoptosis. The results of treating subcutaneous xenograft tumors with a combination of tetrandrine and chloroquine validated that autophagy inhibition enhances the toxicity of tetrandrine against pancreatic cancer in vivo. Altogether, our study demonstrates that tetrandrine induces cytoprotective autophagy in pancreatic cancer cells. Inhibiting tetrandrine-induced autophagy promotes the accumulation of ROS and enhances its toxicity against pancreatic cancer.

Activation of the cGMP/PKG/ERK signaling pathway associated with PDE5Is inhibits fibroblast activation by downregulating autophagy in early progressive benign prostatic hyperplasia

PURPOSE

Benign prostatic hyperplasia (BPH) is one of the most prevalent diseases affecting aging males. However, approximately, 8% of the BPH patients under 50-year-old experience remarkably early progression, for reasons that remain elusive. Among the various factors implicated in promoting BPH advancement, the activation of fibroblasts and autophagy hold particular importance. Our research endeavors to explore the mechanisms behind the accelerated progression in these patients.

METHODS

Immunohistochemistry and immunofluorescence were performed to detect the expression levels of LC3, p62, PDE5, and α-SMA in diverse BPH tissues and prostate stromal cells. The autophagy activator rapamycin, the autophagy suppressor chloroquine, and siRNA transfection were used to identify the impact of autophagy on fibroblast activation.

RESULTS

Prostatic stromal fibroblasts in early progressive BPH tissues displayed activation of autophagy with an upregulation of LC3 and a concurrent downregulation of p62. After starvation or rapamycin treatment to a heightened level of autophagy, fibroblasts exhibited activation. Conversely, chloroquine treatment and ATG-7-knockdown effectively suppressed the level of autophagy and fibroblast activation. High expression of PDE5 was found in early progressive BPH stromal cells. The administration of PDE5 inhibitors (PDE5Is) hindered fibroblast activation through suppressing autophagy by inhibiting the ERK signaling pathway.

CONCLUSION

Our findings suggest that autophagy plays a pivotal role in promoting BPH progression through fibroblast activation, while PDE5Is effectively suppress autophagy and fibroblast activation via the ERK signaling pathway. Nevertheless, further investigations are warranted to comprehensively elucidate the role of autophagy in BPH progression.

Bortezomib modulated the autophagy-lysosomal pathway in a TFEB-dependent manner in multiple myeloma

OBJECTIVE

To explore the involvement of TFEB-mediated autophagy-lysosomal mechanisms in multiple myeloma (MM) during bortezomib treatment.

METHODS

MM cells were exposed to bortezomib or subjected to TFEB knockdown. CCK assay was used to assess the cell proliferation. Western blotting and fluorescent staining were conducted to examine autophagy and lysosomes. The TFEB expression pattern was analyzed, and whole transcriptome sequencing was carried out. Additionally, TFEB target genes were predicted using the GTRD(http://gtrd.biouml.org/) website, and pathway analysis was performed.

RESULTS

Bortezomib demonstrated a dose-dependent and time dependent inhibition of cell proliferation. In MM cells treated with bortezomib, LC3B, Beclin-1, TFEB, and Lamp1 exhibited upregulation in a time- and concentration-dependent manner. LysoTracker dye labeling showed an increase in lysosomes in the bortezomib-treated group. Moreover, bortezomib elevated the expression of lysosome-associated factor Lamp1. Bortezomib promoted the nuclear translocation of TFEB, leading to decreased cytoplasmic TFEB and increased nuclear TFEB. TFEB gene silencing reversed bortezomib's inhibitory effect on MM cell lines, significantly reducing autophagosome expression and lysosome numbers. Furthermore, bioinformatic analysis identified the MAPK pathway as a potential downstream target of TFEB.

CONCLUSION

Bortezomib effectively inhibits MM cell proliferation and induces autophagy, partly through TFEB-mediated mechanisms, with potential involvement of the MAPK pathway.