Loperamide induces protective autophagy and apoptosis through the ROS/JNK signaling pathway in bladder cancer

Maackiain induces apoptosis and autophagy via ROS-mediated endoplasmic reticulum stress in endometrial cancer

Endometrial cancer (EC) is a common gynecological cancer, characterized by increasing incidence and mortality rates. Maackiain (MA), a natural flavonoid compound, has multiple biological activities, but little is known about how it affects EC cells. In the present study, CCK-8, EdU, colony formation, and flow cytometry assays were used to evaluate the effects of MA on EC cell proliferation, apoptosis, and reactive oxygen species (ROS) levels. The effect of MA on autophagy in EC cells were examined through the observation of cell morphology and ultrastructure, and cells were transfected with AdPlus-mCherry-GFP-LC3B for further analysis. Transcriptomic and western blot analyses revealed the underlying mechanism. To evaluate the anti-EC effect of MA in vivo, a xenograft model was established. The results demonstrated that MA inhibited KLE and Ishikawa cell growth in a dose-dependent manner. Furthermore, MA significantly suppressed EC xenograft tumor growth in vivo while exhibiting low toxicity. In addition, EC cells treated with MA exhibited pro-apoptotic and pro-autophagic responses, with the latter exhibiting cytoprotective properties. MA also induced the accumulation of ROS, which promoted endoplasmic reticulum (ER) stress. Notably, the use of the N-acetyl-L-cysteine (NAC) ROS scavenger and the 4-phenylbutyric acid (4-PBA) ER stress inhibitor effectively mitigated the autophagy and apoptosis induced by MA. These results collectively implied that MA triggers autophagy and apoptosis in EC cells through ROS-mediated ER stress, highlighting its potential as a therapeutic agent against EC.

Autophagy in cancer development, immune evasion, and drug resistance

Macroautophagy/autophagy is a highly conserved evolutionary mechanism involving lysosomes for the degradation of cytoplasmic components including organelles. The constitutive, basal level of autophagy is fundamental for preserving cellular homeostasis; however, alterations in autophagy can cause disease pathogenesis, including cancer. The role of autophagy in cancer is particularly complicated, since this process acts both as a tumor suppressor in precancerous stages but facilitates tumor progression during carcinogenesis and later stages of cancer progression. This shift between anti-tumor and pro-tumor roles may be influenced by genetic and environmental factors modulating key pathways such as those involving autophagy-related proteins, the PI3K-AKT-MTOR axis, and AMPK, which often show dysregulation in tumors. Autophagy regulates various cellular functions, including metabolism of glucose, glutamine, and lipids, cell proliferation, metastasis, and several types of cell death (apoptosis, ferroptosis, necroptosis and immunogenic cell death). These multifaceted roles demonstrate the potential of autophagy to affect DNA damage repair, cell death pathways, proliferation and survival, which are critical in determining cancer cells' response to chemotherapy. Therefore, targeting autophagy pathways presents a promising strategy to combat chemoresistance, as one of the major reasons for the failure in cancer patient treatment. Furthermore, autophagy modulates immune evasion and the function of immune cells such as T cells and dendritic cells, influencing the tumor microenvironment and cancer's biological behavior. However, the therapeutic targeting of autophagy is complex due to its dual role in promoting survival and inducing cell death in cancer cells, highlighting the need for strategies that consider both the beneficial and detrimental effects of autophagy modulation in cancer therapy. Hence, both inducers and inhibitors of autophagy have been introduced for the treatment of cancer. This review emphasizes the intricate interplay between autophagy, tumor biology, and immune responses, offering insights into potential therapeutic approaches that deploy autophagy in the cancer suppression.

Targeting autophagy in urological system cancers: From underlying mechanisms to therapeutic implications

The urological system, including kidneys, ureters, bladder, urethra and prostate is known to be vital for blood filtration, waste elimination and electrolyte balance. Notably, urological system cancers represent a significant portion of global cancer diagnoses and mortalities. The current therapeutic strategies for early-stage cancer primarily involve resection surgery, which significantly affects the quality of life of patients, whereas advanced-stage cancer often relies on less effective chemo- or radiotherapy. Recently, accumulating evidence has revealed that autophagy, a crucial process in which excess organelles or inclusions within cells are removed to maintain cell homeostasis, has numerous links to urological system cancers. In this review, we focus on summarizing the underlying two-sided mechanisms of autophagy in urological system cancers. We also review the current clinical drugs targeting autophagy, which demonstrate significant potential in improving treatment outcomes for urological system cancers. In addition, we provide an overview of the research status of novel small molecule compounds targeting autophagy that are in the preclinical stages of investigation. Furthermore, drug combinations based on autophagy modulation strategies in urological system cancers are systematically summarized and discussed. These findings provide comprehensive new insight for the future discovery of more autophagy-related drug candidates.

Alendronate sodium induces G1 phase arrest and apoptosis in human umbilical vein endothelial cells by inhibiting ROS-mediated ERK1/2 signaling

Bisphosphonates are potent bone resorption inhibitors, among which alendronate sodium (ALN) is commonly prescribed for most osteoporosis patients, but long-term application of ALN can cause bisphosphonate-related osteonecrosis of jaw (BRONJ), the pathogenesis of which remains unclear. Previous studies have suggested that bisphosphonates cause jaw ischemia by affecting the biological behavior of vascular endothelial cells, leading to BRONJ. However, the impacts of ALN on vascular endothelial cells and its mechanism remain unclear. The purpose of this work is to assess the influence of ALN on human umbilical vein endothelial cells (HUVECs) and clarify the molecular pathways involved. We found that high concentration of ALN induced G1 phase arrest in HUVECs, demonstrated by downregulation of Cyclin D1 and Cyclin D3. Moreover, high concentration of ALN treatment showed pro-apoptotic effect on HUVECs, demonstrated by increased levels of the cleaved caspase-3, the cleaved PARP and Bax, along with decreased levels of anti-apoptotic protein Bcl-2. Further experiments showed that ERK1/2 phosphorylation was decreased. Additionally, ALN provoked the build-up of reactive oxygen species (ROS) in HUVECs, leading to ERK1/2 pathway suppression. N-acetyl-L-cysteine (NAC), a ROS scavenger, efficiently promoted the ERK1/2 phosphorylation and mitigated the G1 phase arrest and apoptosis triggered by ALN in HUVECs. PD0325901, an inhibitor of ERK1/2 that diminishes the ERK1/2 phosphorylation enhanced the ALN-induced G1 phase arrest and apoptosis in HUVECs. These findings show that ALN induces G1 phase arrest and apoptosis through ROS-mediated ERK1/2 pathway inhibition in HUVECs, providing novel insights into the pathogenic process, prevention and treatment of BRONJ in individuals receiving extended use of ALN.

Betulinic acid induces apoptosis of HeLa cells via ROS-dependent ER stress and autophagy in vitro and in vivo

Betulinic acid (BA), a naturally occurring lupane-type triterpenoid, possesses a wide range of potential activities against different types of cancer. However, the molecular mechanisms involved in anti-cervical cancer about BA were rarely investigated. Herein, the role of BA in cervical cancer suppression by ROS-mediated endoplasmic reticulum stress (ERS) and autophagy was deeply discussed. The findings revealed that BA activated Keap1/Nrf2 pathway and triggered mitochondria-dependent apoptosis due to ROS production. Furthermore, BA increased the intracellular Ca2+ levels, inhibited the expression of Beclin1 and promoted the expression of GRP78, LC3-II, and p62 associated with ERS and autophagy. Besides, BA initiated the formation of autophagosomes and inhibited autophagic flux by the co-administration of BA with 3-methyladenine (3-MA) and chloroquine (CQ), respectively. The in vivo experiment manifested that hydroxychloroquine (HCQ) enhanced the apoptosis induced by BA. For the first time, we demonstrated that BA could initiate early autophagy, inhibit autophagy flux, and induce protective autophagy in HeLa cells. Thus, BA could be a potential chemotherapy drug for cervical cancer, and inhibition of autophagy could enhance the anti-tumor effect of BA. However, the interactions of signaling factors between ERS-mediated and autophagy-mediated apoptosis deserve further attention.

Autophagy flux in bladder cancer: Cell death crosstalk, drug and nanotherapeutics

Autophagy, a self-digestion mechanism, has emerged as a promising target in the realm of cancer therapy, particularly in bladder cancer (BCa), a urological malignancy characterized by dysregulated biological processes contributing to its progression. This highly conserved catabolic mechanism exhibits aberrant activation in pathological events, prominently featured in human cancers. The nuanced role of autophagy in cancer has been unveiled as a double-edged sword, capable of functioning as both a pro-survival and pro-death mechanism in a context-dependent manner. In BCa, dysregulation of autophagy intertwines with cell death mechanisms, wherein pro-survival autophagy impedes apoptosis and ferroptosis, while pro-death autophagy diminishes tumor cell survival. The impact of autophagy on BCa progression is multifaceted, influencing metastasis rates and engaging with the epithelial-mesenchymal transition (EMT) mechanism. Pharmacological modulation of autophagy emerges as a viable strategy to impede BCa progression and augment cell death. Notably, the introduction of nanoparticles for targeted autophagy regulation holds promise as an innovative approach in BCa suppression. This review underscores the intricate interplay of autophagy with cell death pathways and its therapeutic implications in the nuanced landscape of bladder cancer.