Autophagy is a double-edged sword in the therapy of colorectal cancer

Isoxazole based nucleosides induce autophagy through the production of ROS and the suppression of the β-catenin pathway in human colorectal carcinoma cells

β-catenin is frequently implicated in signaling pathways that regulate autophagy, and the production of reactive oxygen species (ROS) has been linked to autophagy activation. Isoxazole-based nucleoside compounds have demonstrated anti-cancer properties. In this study, we report the identification of novel isoxazole-nucleosides as anti-tumor agents and their impact on autophagy in human colorectal carcinoma (CRC) cells. Among the ITP series, ITP-7 and ITP-9 (ITP-7/9) exhibited significant cytotoxicity compared to other compounds. Treatment with ITP-7/9 upregulated the expression of key autophagy-related proteins, including LC3 II, Atg7, and phosphorylated Beclin-1. Additionally, ITP-7/9 promoted the formation of LC3 II puncta and increased the number of AO-stained and MDC-stained cells, indicating enhanced autophagy. ROS levels were elevated following ITP-7/9 exposure, and treatment with N-acetyl l-cysteine (NAC), a ROS inhibitor, reduced the ITP-7/9-induced expression of LC3 II. Furthermore, ITP-7/9 inhibited β-catenin's role as a transcription factor, as observed in ICC assays. Moreover, cells with β-catenin gene deletion exhibited stronger autophagy when treated with ITP-7/9 compared to those treated with ITP-7/9 alone. These findings suggest that ITP-7/9 induces autophagy and promotes CRC cell death by downregulating β-catenin.

Epigenetic modulation of autophagy pathway by small molecules in colorectal cancer: a systematic review

PURPOSE

Colorectal cancer (CRC) remains a global health challenge with limited treatment success due to drug resistance. Recent research highlights the potential of small molecules to modulate CRC by targeting epigenetics or autophagy pathways. This systematic review explores the epigenetic effect of small molecules on autophagy in CRC, aiming to identify novel therapeutic strategies.

METHODS

Following PRISMA guidelines, we systematically reviewed 508 studies from PubMed, Scopus, and Web of Science databases until August 13, 2023.

RESULTS

Eight studies met inclusion criteria, examining the role of small molecules as epigenetic modulators (Histone acetylation/deacetylation, DNA methylation/demethylation and gene expression regulation by miRNAs) influencing the autophagy pathway in CRC. The studies encompassed in vitro and animal model in vivo studies. Small molecules exhibited diverse effects on autophagy in CRC. For instance, panobinostat promoted autophagy leading to CRC cell death, while aspirin inhibited autophagy flux, reducing aspirin-mediated CRC cell death. The epigenetic modulation of autophagy by various small molecules differently affects their anticancer effect, which underscores the complexity of therapeutic interventions.

CONCLUSION

Understanding the intricate dynamics among small molecules, epigenetic modifications, and autophagy in CRC is crucial for developing targeted therapeutic strategies. Considering the dual role of autophagy in tumorigenesis and tumor suppression, administration of these small molecules may differently affect the cancer cell fate and drug response or resistance based on their effect on the autophagy pathway. Therefore, recognition of the epigenetics mechanism of anticancer small molecules on autophagy may contribute to deciding how to prescribe them for better CRC treatment.

Application of Nanomaterials and Related Drug Delivery Systems in Autophagy

Autophagy, a lysosomal self-degradation pathway, plays a critical role in cellular homeostasis by degrading endogenous damaged organelles and protein aggregates into recyclable biological molecules. Additionally, it detoxifies extracellular toxic substances, including drugs and toxic materials, thereby preserving the stability of the intracellular environment. The swift progression of nanotechnology has led to an increased focus on understanding the relationship between nanomaterials and autophagy. The effects of various nanomaterials and nano drug delivery systems on autophagy and their biological functions have been preliminarily assessed, revealing that modulation of intracellular autophagy levels by these agents represents a novel cellular response mechanism. Notably, autophagy regulation based on nanomaterials or nano drug delivery systems for a range of diseases is currently the subject of extensive research. Given the close association between autophagy levels and tumors, the regulation of autophagy has emerged as a highly active area of research in the development of innovative tumor therapies. This review synthesizes the current understanding of the application of nanomaterials or nano drug delivery systems on autophagy and their potential biological functions, suggesting a new avenue for nanomaterial-based autophagy regulation.

Endoplasmic reticulum stress and quality control in relation to cisplatin resistance in tumor cells

The endoplasmic reticulum (ER) is a crucial organelle that orchestrates key cellular functions like protein folding and lipid biosynthesis. However, it is highly sensitive to disturbances that lead to ER stress. In response, the unfolded protein response (UPR) activates to restore ER homeostasis, primarily through three sensors: IRE1, ATF6, and PERK. ERAD and autophagy are crucial in mitigating ER stress, yet their dysregulation can lead to the accumulation of misfolded proteins. Cisplatin, a commonly used chemotherapy drug, induces ER stress in tumor cells, activating complex signaling pathways. Resistance to cisplatin stems from reduced drug accumulation, activation of DNA repair, and anti-apoptotic mechanisms. Notably, cisplatin-induced ER stress can dualistically affect tumor cells, promoting either survival or apoptosis, depending on the context. ERAD is crucial for degrading misfolded proteins, whereas autophagy can protect cells from apoptosis or enhance ER stress-induced apoptosis. The complex interaction between ER stress, cisplatin resistance, ERAD, and autophagy opens new avenues for cancer treatment. Understanding these processes could lead to innovative strategies that overcome chemoresistance, potentially improving outcomes of cisplatin-based cancer treatments. This comprehensive review provides a multifaceted perspective on the complex mechanisms of ER stress, cisplatin resistance, and their implications in cancer therapy.

The role of autophagy in prostate cancer and prostatic diseases: a new therapeutic strategy

BACKGROUND

Autophagy is a well-conserved catabolic process that plays a key role in cell homeostasis. In the prostate, defective autophagy has been implicated in the genesis and progression of several pathological conditions.

AIM

The present review explored the autophagy pathway in prostate-related dysfunctions, focusing on prostate cancer (PCa), benign prostatic hyperplasia (BPH) and prostatitis.

RESULTS

Impaired autophagy activity has been shown in animal models of BPH and prostatitis. Moreover, autophagy activation by specific and non-specific drugs improved both conditions in pre-clinical studies. Conversely, the efficacy of autophagy inducers in PCa remains controversial, depending on intrinsic PCa characteristics and stage of progression. Intriguingly, autophagy inhibitors have shown beneficial effects in PCa suppression or even to overcome chemotherapy resistance. However, there are still open questions regarding the upstream mechanisms by which autophagy is deregulated in the prostate and the exact role of autophagy in PCa. The lack of specificity and increased toxicity associated with the currently autophagy inhibitors limits its use clinically, reflecting in reduced number of clinical data.

CONCLUSION

New therapeutic strategies to treat prostatic diseases involving new autophagy modulators, combination therapy and new drug formulations should be explored. Understanding the autophagy signaling in each prostatic disease is crucial to determine the best pharmacological approach.

Osthole impairs mitochondrial metabolism and the autophagic flux in colorectal cancer

BACKGROUND

Osthole is active constituent of Cnidium monnieri (L.) Cuss. with various physiological functions including anti-inflammation and anti-lipedemic effects. However, the regulatory activity of osthole in colorectal cancer development, focusing on mitochondrial metabolism, is not well known.

HYPOTHESIS/PURPOSE

We hypothesized that osthole may suppress progression of colorectal cancer and aimed to determine the underlying mitochondrial metabolism and the autophagic flux.

STUDY DESIGN

In this study, we elucidated the mechanism of action of osthole in colorectal cancer using an in vivo azoxymethane/dextran sodium sulfate (AOM/DSS) mouse model and an in vitro cell culture system.

METHODS

AOM/DSS mouse model was established and analyzed the effects of osthole on survival rate, diseases activity index, number of tumor and histopathology. Then, cell based assays including viability, cell cycle, reactive oxygen species (ROS), apoptosis, calcium efflux, and mitochondrial function were analyzed. Moreover, osthole-mediated signaling was demonstrated by western blot analyses.

RESULTS

Osthole effectively suppressed the growth of colorectal tumors and alleviated AOM/DSS-induced intestinal injury. Osthole restored the function of goblet cells and impaired the expression of Claudin1 and Axin1 impaired by AOM/DSS. In addition, osthole specifically showed cytotoxicity in colorectal carcinoma cells, but not in normal colon cells. Osthole decreased the ASC/caspase-1/IL-1β inflammasome pathway and induced mitochondrial dysfunction in redox homeostasis, calcium homeostasis. Furthermore, osthole inhibited both oxidative phosphorylation (OXPHOS) and glycolysis, leading to the suppression of ATP production. Moreover, via combination treatment with chloroquine (CQ), we demonstrated that osthole impaired autophagic flux, leading to apoptosis of HCT116 and HT29 cells. Finally, we elucidated that the functional role of tiRNAHisGTG regulated by osthole directly affects the cellular fate of colon cancer cells.

CONCLUSION

These results suggest that osthole has the potential to manage progression of colorectal cancer by regulating autophagy- and mitochondria-mediated signal transduction.

The Role of Beclin 1 and HER2 in Colorectal Carcinoma; An Immunohistochemical Study

OBJECTIVE

This study aimed to evaluate the expression of Beclin 1 and HER2 proteins using immunohistochemistry in CRC tissues compared to colonic adenoma, and to investigate the correlation of their expression with clinicopathological parameters and survival outcomes in CRC patients.

METHODS

The study utilized paraffin-embedded blocks from 17 colonic adenoma and 81 CRC cases. Immunohistochemical analysis was performed to assess the expression of Beclin 1 and HER2 proteins.

RESULTS

The cytoplasmic expression of Beclin 1 was significantly higher in CRC tissues compared to adenoma specimens (P=0.051). High Beclin 1 expression was significantly associated with distal colon location (P=0.028). High HER2 cytoplasmic expression was significantly associated with vascular invasion (P=0.05), perineural invasion (P=0.03), and shorter overall survival (P=0.035).

CONCLUSIONS

The findings suggest that Beclin 1 plays a role in colorectal carcinogenesis, with higher expression observed in CRC cases compared to adenoma cases.  Furthermore, HER2 carries poor prognostic impact in CRC cases.

Adjuvant role of Salvia miltiorrhiza bunge in cancer chemotherapy: A review of its bioactive components, health-promotion effect and mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

Chemotherapy is a common cancer treatment strategy. However, its effectiveness is constrained by toxicity and adverse effects. The Lamiaceae herb Salvia miltiorrhiza Bunge has a long history of therapeutic use in the treatment of blood stasis illnesses, which are believed by traditional Chinese medicine to be connected to cancer.

AIM OF THE STUDY

This review summarized the common toxicity of chemotherapy and the potential chemo-adjuvant effect and mechanisms of active ingredients from S. miltiorrhiza, hoping to provide valuable information for the development and application of S. miltiorrhiza resources.

MATERIALS AND METHODS

The literatures were retrieved from PubMed, Web of Science, Baidu Scholar and Google Scholar databases from 2002 to 2022. The inclusion criteria were studies reporting that S. miltiorrhiza or its constituents enhanced the efficiency of chemotherapy drugs or reduced the side effects.

RESULTS

Salvianolic acid A, salvianolic acid B, salvianolic acid C, rosmarinic acid, tanshinone I, tanshinone IIA, cryptotanshinone, dihydrotanshinone I and miltirone are the primary adjuvant chemotherapy components of S. miltiorrhiza. The mechanisms mainly involve inhibiting proliferation, metastasis, and angiogenesis, inducing apoptosis, regulating autophagy and tumor microenvironment. In addition, they also improve chemotherapy drug-induced side effects.

CONCLUSIONS

The bioactive compounds of S. miltiorrhiza are shown to inhibit proliferation, metastasis, and angiogenesis, induce apoptosis and autophagy, regulate immunity and tumor microenvironment when combined with chemotherapy drugs. However, further clinical studies are required to validate the current studies.

Cell death in cancer chemotherapy using taxanes

Cancer cells evolve to be refractory to the intrinsic programmed cell death mechanisms, which ensure cellular tissue homeostasis in physiological conditions. Chemotherapy using cytotoxic drugs seeks to eliminate cancer cells but spare non-cancerous host cells by exploring a likely subtle difference between malignant and benign cells. Presumably, chemotherapy agents achieve efficacy by triggering programmed cell death machineries in cancer cells. Currently, many major solid tumors are treated with chemotherapy composed of a combination of platinum agents and taxanes. Platinum agents, largely cis-platin, carboplatin, and oxaliplatin, are DNA damaging agents that covalently form DNA addicts, triggering DNA repair response pathways. Taxanes, including paclitaxel, docetaxel, and cabazitaxel, are microtubule stabilizing drugs which are often very effective in purging cancer cells in clinical settings. Generally, it is thought that the stabilization of microtubules by taxanes leads to mitotic arrest, mitotic catastrophe, and the triggering of apoptotic programmed cell death. However, the precise mechanism(s) of how mitotic arrest and catastrophe activate the caspase pathway has not been established. Here, we briefly review literature on the involvement of potential cell death mechanisms in cancer therapy. These include the classical caspase-mediated apoptotic programmed cell death, necroptosis mediated by MLKL, and pore forming mechanisms in immune cells, etc. In particular, we discuss a newly recognized mechanism of cell death in taxane-treatment of cancer cells that involves micronucleation and the irreversible rupture of the nuclear membrane. Since cancer cells are commonly retarded in responding to programmed cell death signaling, stabilized microtubule bundle-induced micronucleation and nuclear membrane rupture, rather than triggering apoptosis, may be a key mechanism accounting for the success of taxanes as anti-cancer agents.

Apatinib combined with olaparib induces ferroptosis via a p53-dependent manner in ovarian cancer

OBJECTIVE

PARP inhibitors combined with antiangiogenic drugs have been reported to improve outcomes in BRCA wild-type ovarian cancer patients, the mechanism of the combination is unclear. In this study, we explored the mechanism of apatinib combined with olaparib in the treatment of ovarian cancer.

METHODS

In this study, human ovarian cancer cell lines A2780 and OVCAR3 were used as experimental objects, and the expression of ferroptosis-related protein GPX4 after treatment with apatinib and olaparib was detected by Western blot. The SuperPred database was used to predict the target of the combined action of apatinib and olaparib, and the predicted results were verified by Western blot experiment to explore the mechanism of ferroptosis induced by apatinib and olaparib.

RESULTS

Apatinib combined with olaparib-induced ferroptosis in p53 wild-type cells, and p53 mutant cells developed drug resistance. The p53 activator RITA sensitized drug-resistant cells to ferroptosis induced by apatinib combined with olaparib. Apatinib combined with olaparib-induced ferroptosis via a p53-dependent manner in ovarian cancer. Further studies showed that apatinib combined with olaparib-induced ferroptosis by inhibiting the expression of Nrf2 and autophagy, thereby inhibiting the expression of GPX4. The Nrf2 activator RTA408 and the autophagy activator rapamycin rescued the combination drug-induced ferroptosis.

CONCLUSION

This discovery revealed the specific mechanism of ferroptosis induced by apatinib combined with olaparib in p53 wild-type ovarian cancer cells and provided a theoretical basis for the clinical combined use of apatinib and olaparib in p53 wild-type ovarian cancer patients.

High-Dose Spermidine Supplementation Does Not Increase Spermidine Levels in Blood Plasma and Saliva of Healthy Adults: A Randomized Placebo-Controlled Pharmacokinetic and Metabolomic Study

(1) Background: Spermidine is a biogenic polyamine that plays a crucial role in mammalian metabolism. As spermidine levels decline with age, spermidine supplementation is suggested to prevent or delay age-related diseases. However, valid pharmacokinetic data regarding spermidine remains lacking. Therefore, for the first time, the present study investigated the pharmacokinetics of oral spermidine supplementation. (2) Methods: This study was designed as a randomized, placebo-controlled, triple-blinded, two-armed crossover trial with two 5-day intervention phases separated by a washout phase of 9 days. In 12 healthy volunteers, 15 mg/d of spermidine was administered orally, and blood and saliva samples were taken. Spermidine, spermine, and putrescine were quantified by liquid chromatography-mass spectrometry (LC-MS/MS). The plasma metabolome was investigated using nuclear magnetic resonance (NMR) metabolomics. (3) Results: Compared with a placebo, spermidine supplementation significantly increased spermine levels in the plasma, but it did not affect spermidine or putrescine levels. No effect on salivary polyamine concentrations was observed. (4) Conclusions: This study's results suggest that dietary spermidine is presystemically converted into spermine, which then enters systemic circulation. Presumably, the in vitro and clinical effects of spermidine are at least in part attributable to its metabolite, spermine. It is rather unlikely that spermidine supplements with doses <15 mg/d exert any short-term effects.

Induction of Apoptosis and Decrease of Autophagy in Colon Cancer Cells by an Extract of Lyophilized Mango Pulp

Previous studies have indicated that mango fruit has a chemopreventive capacity against colorectal cancer cells. The objective of this research was to evaluate the effect of an aqueous extract of lyophilized mango pulp (LMPE) on colon adenocarcinoma cells (SW480) and their metastatic derivatives (SW620) death and cellular invasion. DNA fragmentation was assessed by TUNEL assay; autophagy and expression of DR4 and Bcl-2 by flow cytometry; the expression of 35 apoptosis-related proteins and of matrix metalloproteinases 7 and 9 by immunodetection; and the invasive capacity of the cells by Boyden chamber. The results showed that LMPE at 30 mg/mL and 48 h of exposure results in DNA fragmentation and apoptosis in SW480 (p < 0.001) and SW620 (p < 0.01) cells. Additionally, LMPE decreased autophagy in the SW480 and SW620 cell lines (p < 0.001), which could sensitize them to the DNA damage generated by LMPE. The LMPE did not modulate the expression of matrix metalloproteinases 7 and 9, nor did it affect cellular invasion processes in the SW480 and SW620 cell lines. In conclusion, LMPE induces apoptosis and decreases autophagy in SW480 and SW620 cells.

Autophagy and the Insulin-like Growth Factor (IGF) System in Colonic Cells: Implications for Colorectal Neoplasia

Colorectal cancer (CRC) is one of the most common human malignancies worldwide. Along with apoptosis and inflammation, autophagy is one of three important mechanisms in CRC. The presence of autophagy/mitophagy in most normal mature intestinal epithelial cells has been confirmed, where it has mainly protective functions against reactive oxygen species (ROS)-induced DNA and protein damage. Autophagy regulates cell proliferation, metabolism, differentiation, secretion of mucins and/or anti-microbial peptides. Abnormal autophagy in intestinal epithelial cells leads to dysbiosis, a decline in local immunity and a decrease in cell secretory function. The insulin-like growth factor (IGF) signaling pathway plays an important role in colorectal carcinogenesis. This is evidenced by the biological activities of IGFs (IGF-1 and IGF-2), IGF-1 receptor type 1 (IGF-1R) and IGF-binding proteins (IGF BPs), which have been reported to regulate cell survival, proliferation, differentiation and apoptosis. Defects in autophagy are found in patients with metabolic syndrome (MetS), inflammatory bowel diseases (IBD) and CRC. In neoplastic cells, the IGF system modulates the autophagy process bidirectionally. In the current era of improving CRC therapies, it seems important to investigate the exact mechanisms not only of apoptosis, but also of autophagy in different populations of tumor microenvironment (TME) cells. The role of the IGF system in autophagy in normal as well as transformed colorectal cells still seems poorly understood. Hence, the aim of the review was to summarize the latest knowledge on the role of the IGF system in the molecular mechanisms of autophagy in the normal colon mucosa and in CRC, taking into account the cellular heterogeneity of the colonic and rectal epithelium.

The Activation of Reticulophagy by ER Stress through the ATF4-MAP1LC3A-CCPG1 Pathway in Ovarian Granulosa Cells Is Linked to Apoptosis and Necroptosis

Female infertility is caused by premature ovarian failure (POF), which is triggered by the endoplasmic reticulum (ER) stress-mediated apoptosis of granulosa cells. The ER unfolded protein response (UPR^er) is initiated to promote cell survival by alleviating excessive ER stress, but cellular apoptosis is induced by persistent or strong ER stress. Recent studies have reported that reticulophagy is initiated by ER stress. Whether reticulophagy is activated in the ER stress-mediated apoptosis of granulosa cells and which pathway is initiated to activate reticulophagy during the apoptosis of granulosa cells are unknown. Therefore, the role of reticulophagy in granulosa cell death and the relationship between ER stress and reticulophagy were investigated in this work. Our results suggest that the ER stress inducer tunicamycin causes POF in mice, which is attributed to the apoptosis of granulosa cells and is accompanied by the activation of UPR^er and reticulophagy. Furthermore, granulosa cells were treated with tunicamycin, and granulosa cell apoptosis was triggered and increased the expression of UPR^er and reticulophagy molecules. The expression of ATF4 was then downregulated by RNAi, which decreased the levels of autophagy and the reticulophagy receptor CCGP1. Furthermore, ATF4 targets MAP1LC3A, as revealed by the ChIP sequencing results, and co-IP results demonstrated that MAP1LC3A interacts with CCPG1. Therefore, reticulophagy was activated by ER stress through the ATF4-MAP1LC3A-CCPG1 pathway to mitigate ER stress. Additionally, the role of reticulophagy in granulosa cells was investigated by the knockdown of CCPG1 with RNAi. Interestingly, only a small number of granulosa cells died by apoptosis, whereas the death of most granulosa cells occurred by necroptosis triggered by STAT1 and STAT3 to impair ER proteostasis and the ER protein quality control system UPR^er. Taken together, the results indicate that the necroptosis of granulosa cells is triggered by up- and downregulating the reticulophagy receptor CCPG1 through STAT1/STAT3-(p)RIPK1-(p)RIPK3-(p)MLKL and that reticulophagy is activated by ER stress through the ATF4-MAP1LC3A-CCPG1 pathway.

Polyphyllin II induced apoptosis of NSCLC cells by inhibiting autophagy through the mTOR pathway

CONTEXT

Polyphyllin II (PPII) is a steroidal saponin isolated from Rhizoma Paridis. It exhibits significant antitumor activity such as anti-proliferation and pro-apoptosis in lung cancer.

OBJECTIVE

To explore whether PPII induce autophagy and the relationship between autophagy and apoptosis in non-small cell lung cancer (NSCLC) cells.

MATERIALS AND METHODS

The effects of PPII (0, 1, 5, and 10 μM) were elucidated by CCK8 assay, colony formation test, TUNEL staining, MDC method, and mRFP-GFP-LC3 lentivirus transfection in A549 and H1299 cells for 24 h. DMSO-treated cells were selected as control. The protein expression of autophagy (LC3-II, p62), apoptosis (Bcl-2, Bax, caspase-3) and p-mTOR was detected by Western blotting. We explored the relationship between autophagy and apoptosis by autophagy inhibitor CQ (10 μM) and 3-MA (5 mM).

RESULTS

PPII (0, 1, 5, and 10 μM) inhibited the proliferation and induced apoptosis. The IC₅₀ values of A549 and H1299 cells were 8.26 ± 0.03 and 2.86 ± 0.83 μM. We found that PPII could induce autophagy. PPII promoted the formation of autophagosome, increased the expression of LC3-II/LC3-I (p < 0.05), while decreased p62 and p-mTOR (p < 0.05). Additionally, the co-treatment with autophagy inhibitors promoted the protein expression of c-caspase-3 and rate of Bax/Bcl-2 (p < 0.05), compared with PPII-only treatment group. Therefore, our results indicated that PPII-induced autophagy may be a mechanism to promote cell survival, although it can also induce apoptosis.

CONCLUSIONS

PPII-induced apoptosis exerts its anticancer activity by inhibiting autophagy, which will hopefully provide a prospective compound for NSCLC treatment.

Focusing on the Role of Natural Products in Overcoming Cancer Drug Resistance: An Autophagy-Based Perspective

Autophagy is a critical cellular adaptive response in tumor formation. Nutritional deficiency and hypoxia exacerbate autophagic flux in established malignancies, promoting tumor cell proliferation, migration, metastasis, and resistance to therapeutic interventions. Pro-survival autophagy inhibition may be a promising treatment option for advanced cancer. Furthermore, excessive or persistent autophagy is cytotoxic, resulting in tumor cell death. Targeted autophagy activation has also shown significant promise in the fight against tumor drug resistance. Several research groups have examined the ability of natural products (NPs) such as alkaloids, terpenoids, polyphenols, and anthraquinones to serve as autophagy inhibitors or activators. The data support the capacity of NPs that promote lethal autophagy or inhibit pro-survival autophagy from being employed against tumor drug resistance. This paper discusses the potential applications of NPs that regulate autophagy in the fight against tumor drug resistance, some limitations of the current studies, and future research needs and priorities.

The marine natural product, dicitrinone B, induces apoptosis through autophagy blockade in breast cancer

Being a highly conserved catabolic process, autophagy is induced by various forms of cellular stress, and its modulation has considerable potential as a cancer therapeutic approach. In the present study, it was demonstrated that dicitrinone B (DB), a rare carbon-bridged citrinin dimer, may exert anticancer effects by blocking autophagy at a late stage, without disrupting lysosomal function in MCF7 breast cancer and MDA-MB-231 triple-negative breast cancer cells. Furthermore, it was discovered that DB significantly enhanced intracellular reactive oxygen species (ROS) production and that the removal of ROS was followed by the attenuation of autophagy inhibition. In addition, DB exerted notable inhibitory effects on the proliferation and promoting effects on the apoptosis of MCF7 and MDA-MB-231 cells. In combination with conventional chemotherapeutic drugs, DB exhibited a further enhanced synergistic effect than when used as a single agent. Overall, the data of the present study demonstrate that DB may prove to be a promising autophagy inhibitor with anticancer activity against breast cancer.

Nuclear Beclin 1 Destabilizes Retinoblastoma Protein to Promote Cell Cycle Progression and Colorectal Cancer Growth

Simple Summary

The role of autophagy core-protein Beclin 1 in colorectal cancer (CRC) development remains controversial. Here, we show that nuclear Beclin 1 is up-regulated in CRC with a negative correlation to RB protein expression. Silencing of BECN1 up-regulates RB expression resulting in cell cycle G1 arrest and inhibition of xenograft tumor growth independent of p53. Ablation of BECN1 facilitates MDM2–MDMX complex formation to promote MDMX polyubiquitination and degradation, consequently leading to RB protein stabilization. These results reveal that nuclear Beclin 1 can promote CRC growth through modulation of RB protein stability and imply that nuclear Beclin 1 may be a prognostic indicator in human colorectal cancer.

Abstract

Autophagy is elevated in colorectal cancer (CRC) and is generally associated with poor prognosis. However, the role of autophagy core-protein Beclin 1 remains controversial in CRC development. Here, we show that the expression of nuclear Beclin 1 protein is upregulated in CRC with a negative correlation to retinoblastoma (RB) protein expression. Silencing of BECN1 upregulates RB resulting in cell cycle G1 arrest and growth inhibition of CRC cells independent of p53. Furthermore, ablation of BECN1 inhibits xenograft tumor growth through elevated RB expression and reduced autophagy, while simultaneous silencing of RB1 restores tumor growth but has little effect on autophagy. Mechanistically, knockdown of BECN1 promotes the complex formation of MDM2 and MDMX, resulting in MDM2-dependent MDMX instability and RB stabilization. Our results demonstrate that nuclear Beclin 1 can promote cell cycle progression through modulation of the MDM2/X-RB pathway and suggest that Beclin 1 promotes CRC development by facilitating both cell cycle progression and autophagy.

Apigenin in cancer therapy: From mechanism of action to nano-therapeutic agent

Apigenin (APG) is a flavonoid presence in beverages, vegetables, and fruits containing anti-diabetic, anti-oxidant, and anti-viral activities, as well as cancer management properties. There is growing evidence that APG presented extensive anti-cancer effects in several cancer types by modulating various cellular processes, including angiogenesis, apoptosis, metastasis, autophagy, cell cycle, and immune responses, through activation or inhibition of different cell signaling pathways and molecules. By emerging nanotechnology and its advent in the biomedicine field, cancer therapy has been changed based on nanotechnology-based delivery systems. APG nanoformulations have been used to target tumor cells specifically, improve cellular uptake of APG, and overcome limitations of the free form of APG, such as low solubility and poor bioavailability. In this review, the biotherapeutic activity of APG and its mechanisms, both in free form and nanoformulation, toward cancer cells are discussed to shed some light on APG anti-tumor activity in different cancers.

The role of PFKFB3 in maintaining colorectal cancer cell proliferation and stemness

Since generally confronting with the hypoxic and stressful microenvironment, cancer cells alter their glucose metabolism pattern to glycolysis to sustain the continuous proliferation and vigorous biological activities. Bifunctional 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2/FBPase-2) isoform 3 (PFKFB3) functions as an effectively modulator of glycolysis and also participates in regulating angiogenesis, cell death and cell stemness. Meanwhile, PFKFB3 is highly expressed in a variety of cancer cells, and can be activated by several regulatory factors, such as hypoxia, inflammation and cellular signals. In colorectal cancer (CRC) cells, PFKFB3 not only has the property of high expression, but also probably relate to inflammation-cancer transformation. Recent studies indicate that PFKFB3 is involved in chemoradiotherapy resistance as well, such as breast cancer, endometrial cancer and CRC. Cancer stem cells (CSCs) are self-renewable cell types that contribute to oncogenesis, metastasis and relapse. Several studies indicate that CSCs utilize glycolysis to fulfill their energetic and biosynthetic demands in order to maintain rapid proliferation and adapt to the tumor microenvironment changes. In addition, elevated PFKFB3 has been reported to correlate with self-renewal and metastatic outgrowth in numerous kinds of CSCs. This review summarizes our current understanding of PFKFB3 roles in modulating cancer metabolism to maintain cell proliferation and stemness, and discusses its feasibility as a potential target for the discovery of antineoplastic agents, especially in CRC.

Blue light irradiation inhibits the growth of colon cancer and activation of cancer‑associated fibroblasts

Irradiation with a specific wavelength of light using light‑emitting diodes (LEDs) has various effects on cells and organisms. Recently, the antitumor effects of visible blue light on tumor cells were reported; however, the mechanism and effects on the tumor microenvironment remain unclear. Human colon cancer cells (HCT‑116) were injected into the rectal wall of nude mice. Tumors were irradiated with a 465‑nm LED light at 30 mW/cm² for 30 min. Tumor volumes and the expression levels of opsin 3 (Opn3), autophagy‑related factors, cancer‑associated fibroblast (CAF) markers, and programmed cell death 1‑ligand (PD‑L1) were measured. Additionally, human intestinal fibroblasts were cultured in HCT116‑conditioned medium (CM) to prepare CAFs. CAFs were divided into an LED group and a control group, and the effect of the LED light on CAF activation in colon cancer cells was examined. Irradiation with blue LED light suppressed tumor growth; Opn3 expression was localized to the cell membrane in the LED group. Irradiated tumors exhibited increased autophagy‑related gene expression. Furthermore, in the LED group, TGF‑β and α‑SMA expression levels in the fibroblasts were decreased. Regarding CAFs, α‑SMA and IL‑6 expression levels were decreased in the LED group. HCT‑116 cells cultured in CAF‑CM with LED irradiation showed no enhanced migration or invasion. In the HCT‑116 cells cultured in CM of CAFs irradiated with LED, the relative increase in PD‑L1 expression was lower than that noted in the CAF‑CM without LED irradiation. Blue LED light may have a direct antitumor effect on colon cancer and also an inhibitory effect on CAFs.

Autophagy-associated HMGB-1 as a novel potential circulating non-invasive diagnostic marker for detection of Urothelial Carcinoma of Bladder

Urothelial carcinoma of bladder (UBC), a highly prevalent urological malignancy associated with high mortality and recurrence rate. Standard diagnostic method currently being used is cystoscopy but its invasive nature and low sensitivity stresses for identifying predictive diagnostic marker. Autophagy, a cellular homeostasis maintaining process, is usually dysregulated in cancer and its role is still enigmatic in UBC. In this study, 30 UBC patients and healthy controls were enrolled. Histopathologically confirmed tumor and adjacent normal tissue were acquired from patients. Molecular expression and tissue localization of autophagy-associated molecules (HMGB-1, RAGE, beclin, LC-3, and p62) were investigated. Serum HMGB-1 concentration was measured in UBC patients and healthy controls. ROC curves were plotted to evaluate diagnostic potential. Transcript, protein, and IHC expression of HMGB-1, RAGE, beclin, and LC-3 displayed upregulated expression, while p62 was downregulated in bladder tumor tissue. Serum HMGB-1 levels were elevated in UBC patients. Transcript and circulatory levels of HMGB-1 showed positive correlation and displayed a positive trend with disease severity. Upon comparison with clinicopathological parameters, HMGB-1 emerged as molecule of statistical significance to exhibit association. HMGB-1 exhibited optimum sensitivity and specificity in serum. The positive correlation between tissue and serum levels of HMGB-1 showcases serum as a representation of in situ scenario, suggesting its clinical applicability for non-invasive testing. Moreover, optimum sensitivity and specificity displayed by HMGB-1 along with significant association with clinicopathological parameters makes it a potential candidate to be used as diagnostic marker for early detection of UBC but requires further validation in larger cohort.

PPT1 Reduction Contributes to Erianin-Induced Growth Inhibition in Oral Squamous Carcinoma Cells

The anticancer properties of erianin have been recently discovered. However, the antitumor effect of erianin in oral squamous cell carcinoma (OSCC) remains unclear. In this study, we demonstrated that erianin can hamper OSCC cells growth both in vitro and in vivo. Erianin induced obvious G2/M arrest as well as apoptosis and gasdermin E (GSDME)-dependent pyroptosis in OSCC cells. Moreover, erianin increased autophagosome formation but decreased autolysosome function. Further study indicated that erianin significantly suppressed the expression of protein-palmitoyl thioesterase 1 (PPT1) and mTOR signaling. PPT1 has been reported to be a critical regulator of cancer progression by its modulation of autophagy and mTOR signaling. According to online databases, higher expression of PPT1 has been observed in OSCC tissues and is associated with poorer patient prognosis. As overexpression of PPT1 significantly reversed erianin-induced growth inhibition in OSCC cells, we identified the importance of PPT1 reduction in erianin-induced growth suppression. With the xenograft model, we confirmed the antitumor effect of erianin in vivo. Erianin efficiently decreased the tumor sizes, together with visibly reduced expression of PPT1 and phosphorylation of mTOR in the xenograft tumor tissues. Therefore, the present study indicated that erianin may be potentially used in OSCC therapy.

Inhibition of the cell migration, invasion and chemoresistance of colorectal cancer cells through targeting KLF3 by miR-365a-3p

Background: Metastasis and chemoresistance limit treatment efficacy of colorectal cancer (CRC) patients. MicroRNAs (miRNAs) have been believed to be candidate biomarkers for tumor cell proliferation, metastasis and chemoresistance, but the related molecular mechanisms are not clear for prognosis prediction.

Aims: We aimed to investigate the role of miR-365a-3p in metastasis and chemoresistance of CRC.

Methods: The expression levels of miR-365a-3p in clinical CRC tissues were analyzed. The effects of miR-365a-3p expression levels on tumor chemoresistance, invasion and migration were also determined. A dual luciferase reporter gene assay was used to determine the effect of miR-365a-3p on its target gene, Kruppel-like factor 3 (KLF3), and the effect of the miR-365a-3p/KLF3 axis on CRC cell chemoresistance, migration and invasion was further investigated.

Results: In patients with CRC with lymph node or distant organ metastasis or in CRC cell lines, the expression levels of miR-365a-3p were significantly downregulated. In addition, the findings of Transwell assays demonstrated that miR-365a-3p significantly suppressed CRC cell migration and invasion. The dual luciferase reporter gene assay results suggested that miR-365a-3p may play an important role in the regulation of migration, invasion and chemoresistance in CRC cells.

Conclusions: The findings of present study provided evidence to suggest that miR-365a-3p may be a potential tumor suppressor gene in CRC and may inhibit the migration, invasion and chemoresistance of CRC cells. These results suggested that targeting miR-365a-3p/KLF3 axis may represent a potential therapeutic intervention for metastatic disease in patients with CRC.

Liquiritigenin exerts the anti-cancer role in oral cancer via inducing autophagy-related apoptosis through PI3K/AKT/mTOR pathway inhibition in vitro and in vivo

Operative treatment on oral cancer greatly damages the chewing and language function of the patient, we aim to find better solution with fewer side effects. The anti-tumor effects of Liquiritigenin (LQ) have been explored in kinds of cancers, but not in oral cancer. In this study, our purpose is to reveal the effects of LQ on oral cancer and the associated mechanism.Cell proliferation was examined through 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and 5-Ethynyl-2'- deoxyuridine (EDU) staining. Cell apoptosis in cells and tissues were assessed by flow cytometry and terminal dexynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining, respectively. Expressions of AKT and light chain 3 (LC3) were detected through Immunofluorescence. In addition, xenograft model was established by injecting the CAL-27 cells (2 × 10⁶) subcutaneously into the right flanks of mice. Expression of Ki67 and Beclin1 in tissues was valued by Immunohistochemistry (IHC).We found that cell viability of CAL-27 and SCC-9 was effectively inhibited by LQ. Besides, obvious cell apoptosis and cell autophagy were induced by LQ. In addition, PI3K/AKT/mTOR pathway was sharply inactivated by LQ in oral cancer cells. Corresponding in vivo experiments demonstrated that tumor growth was largely restricted, cell apoptosis was augmented and autophagy was enhanced by LQ. What is more, phosphorylation of AKT in tumor tissues could also be inhibited by LQ. LQ inhibited the progression of oral cancer through inducing autophagy-associated apoptosis via PI3K/AKT/mTOR pathway inhibition, revealing a new possible scheme for the treatment of oral cancer.