A novel orally available seleno-purine molecule suppresses triple-negative breast cancer cell proliferation and progression to metastasis by inducing cytostatic autophagy

Recent advancement in developing small molecular inhibitors targeting key kinase pathways against triple-negative breast cancer

Triple-negative breast cancer (TNBC) stands out as the most formidable variant of breast cancer, predominantly affecting younger women and characterized by a bleak outlook and a high likelihood of spreading. The absence of safe and effective targeted treatments leaves standard cytotoxic chemotherapy as the primary option. The role of protein kinases, frequently altered in many cancers, is significant in the advancement and drug resistance of TNBC, making them a logical target for creating new, potent therapies against TNBC. Recently, an array of promising small molecules aimed at various kinases have been developed specifically for TNBC, with combination studies showing a synergistic improvement in combatting this condition. This review underscores the effectiveness of small molecule kinase inhibitors in battling the most lethal form of breast cancer and sheds light on prospective pathways for crafting novel treatments.

Role of circRNAs in regulating cell death in cancer: a comprehensive review

Despite multiple diagnostic and therapeutic advances, including surgery, radiation therapy, and chemotherapy, cancer preserved its spot as a global health concern. Prompt cancer diagnosis, treatment, and prognosis depend on the discovery of new biomarkers and therapeutic strategies. Circular RNAs (circRNAs) are considered as a stable, conserved, abundant, and varied group of RNA molecules that perform multiple roles such as gene regulation. There is evidence that circRNAs interact with RNA-binding proteins, especially capturing miRNAs. An extensive amount of research has presented the substantial contribution of circRNAs in various types of cancer. To fully understand the linkage between circRNAs and cancer growth as a consequence of various cell death processes, including autophagy, ferroptosis, and apoptosis, more research is necessary. The expression of circRNAs could be controlled to limit the occurrence and growth of cancer, providing a more encouraging method of cancer treatment. Consequently, it is critical to understand how circRNAs affect various forms of cancer cell death and evaluate whether circRNAs could be used as targets to induce tumor death and increase the efficacy of chemotherapy. The current study aims to review and comprehend the effects that circular RNAs exert on cell apoptosis, autophagy, and ferroptosis in cancer to investigate potential cancer treatment targets.

Exploring the Geroprotective Potential of Nutraceuticals

Aging is the result of the accumulation of a wide variety of molecular and cellular damages over time, meaning that "the more damage we accumulate, the higher the possibility to develop age-related diseases". Therefore, to reduce the incidence of such diseases and improve human health, it becomes important to find ways to combat such damage. In this sense, geroprotectors have been suggested as molecules that could slow down or prevent age-related diseases. On the other hand, nutraceuticals are another set of compounds that align with the need to prevent diseases and promote health since they are biologically active molecules (occurring naturally in food) that, apart from having a nutritional role, have preventive properties, such as antioxidant, anti-inflammatory and antitumoral, just to mention a few. Therefore, in the present review using the specialized databases Scopus and PubMed we collected information from articles published from 2010 to 2023 in order to describe the role of nutraceuticals during the aging process and, given their role in targeting the hallmarks of aging, we suggest that they are potential geroprotectors that could be consumed as part of our regular diet or administered additionally as nutritional supplements.

Particulate matters 2.5 induce tumor progression in lung cancer by increasing the activity of hnRNPA2B1 resulting in retarding mRNA decay of oxidative phosphorylation

Particulate matter 2.5 (PM2.5) has been implicated in lung injury and various cancers, yet its precise mechanistic role remains elusive. To elucidate the key signaling pathways underpinning PM2.5-induced lung cancer progression, we embarked on a study examining the impact of PM2.5 both in vitro and in vivo. Lung cancer cell lines, A549 and H157, were employed for the in vitro investigations. Overexpression or knockdown techniques targeting the hnRNPA2B1 protein were implemented. Lung cancer cells were treated with a medium containing PM2.5 and subsequently prepared for in vitro evaluations. Cell growth, invasion, and migration were gauged using transwell and CCK-8 assays. Apoptosis was ascertained through flow cytometry and western blotting of pertinent proteins. Seahorse analyses probed the influence of PM2.5 on lung cancer energy metabolism. The RNA stability assay was employed to discern the impact of PM2.5 on the stability of oxidative phosphorylation-related genes in lung cancer. Our findings revealed that PM2.5 augmented cell proliferation, migration, and invasion rates. Similarly, a diminished apoptosis rate was observed in PM2.5-treated cells. Elevated expression of hnRNPA2B1 was detected in lung cancer cells exposed to PM2.5. Moreover, in cells treated with PM2.5, hnRNPA2B1 knockdown markedly curtailed cell proliferation by inducing G1-S cell cycle arrest and bolstered lung cancer cell apoptosis in vitro; it also curbed xenograft tumor growth. Mechanistically, our data suggest that PM2.5 undermines the stability of mRNA transcripts associated with oxidative phosphorylation (OXPHOS) and augments the formation of processing bodies (P-bodies), leading to an upsurge in OXPHOS levels. In conclusion, PM2.5 appears to drive lung cancer progression and migration by modulating the energy metabolism of lung cancer in a hnRNPA2B1-dependent manner.

Selenium and Triple Negative Breast Cancer

BACKGROUND

The deadliest, most dangerous subtype of breast cancer is triple-negative, which lacks treatment targets and accounts for 30% of all breast cancer-related deaths worldwide. TNBC is characterized by the expression of no estrogen, progesterone, or human epidermal growth factor 2 receptors. This suggests that new treatment modalities with fewer adverse effects are required.

OBJECTIVE

The aim of the present study was to investigate the therapeutic potential of selenium compounds as an adjuvant therapy for Triple Negative Breast Cancer (TNBC), either on their own or in conjunction with nutritional supplements and chemotherapy medications.

METHODS

Using the keywords "selenium" and "triple negative breast cancer", a thorough search was conducted in the PubMed database, yielding 23 articles. The following factors were taken into consideration for inclusion: studies using TNBC cell culture lines or in vivo tumors/specimens; full-text articles from the PubMed database; studies published in the English language; experiments with statistically significant results; and selenium used alone or in combination with other antioxidants or chemotherapy. This led to the evaluation of 13 articles in this review.

RESULTS

The results show that selenium therapy increased the anti-cancer drug's effects and produced tumor cytotoxicity, while reducing the cellular features of the cancer (hyperproliferation, growth, and metastasis).

DISCUSSION

This study evaluated the various selenium compounds tested, the cell lines and model organisms used, the assays performed, and the cellular pathways affected.

CONCLUSION

Examining the possible benefits of selenium in TNBC treatment highlights the need for more studies to confirm selenium compounds as viable co-therapeutic agents.

Linc00707 regulates autophagy and promotes the progression of triple negative breast cancer by activation of PI3K/AKT/mTOR pathway

Triple-negative breast cancer (TNBC) is a pathological subtype of breast cancer (BC) with high malignancy, strong invasiveness and poor prognosis. Long non-coding RNA (LncRNA) plays an important role during tumorigenesis. We identified that Linc00707 was upregulated in TNBC tissues by TCGA database and RT-qPCR assay, compared with normal breast tissues and other subtypes of BC. Linc00707 promoted TNBC cells proliferation, migration and invasion. Furthermore, we found that knockdown of Linc00707 influenced autophagy via PI3K/AKT/mTOR signaling pathway in TNBC cells. Linc00707 affected the progress of TNBC cells through affecting autophagy. Further mechanistic experiments confirmed that Linc00707 could competitively bind with miR-423-5p to up-regulate MARCH2 expression, ultimately promoting TNBC progression and autophagy through PI3K/AKT/mTOR pathway. In conclusion, we demonstrate that Linc00707 is a key molecule in tumor progression and may be an effective target for patients with TNBC.

Icariin exerts anti-tumor activity by inducing autophagy via AMPK/mTOR/ULK1 pathway in triple-negative breast cancer

BACKGROUND

Breast cancer is the most prevalent female tumor, of which triple-negative breast cancer (TNBC) accounts for about 15%. Characterized by its aggressive nature and limited treatment options, TNBC currently stands as a significant clinical challenge. This study aimed to investigate the effects of icariin (ICA) on TNBC and explore the underlying molecular mechanism.

METHODS

Cell viability was assessed using CCK-8 assay, whereas the impact of ICA on cell proliferation was determined using colony formation assay and detection of proliferating cell nuclear antigen protein. Wound healing and transwell assays were used to evaluate the effects of ICA on cell migration and invasion, respectively. Flow cytometry was used to analyze cell cycle distribution and apoptosis. Transmission electron microscopy and monodansylcaverine staining were performed to detect the induction of autophagy, whereas molecular docking was conducted to predict the potential targets associated with autophagy. The in vivo anti-tumor effects of ICA were evaluated using a TNBC 4T1 xenograft mouse model. Protein expression levels were examined using immunoblotting and immunohistochemistry.

RESULTS

In vitro, ICA effectively suppressed the viability, proliferation, migration, and invasion of TNBC cells and induced G0/G1 phase cell cycle arrest, apoptosis, and autophagy in TNBC cells by regulating the adenosine monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR)/Unc-51-like kinase 1 (ULK1) signaling pathway. The knockdown of AMPK and inhibition of autophagy with 3-methyladenine reversed the effects of ICA, highlighting the importance of AMPK and autophagy in the anti-cancer mechanism of ICA. In vivo, ICA significantly inhibited TNBC growth, promoted autophagy, and regulated AMPK/mTOR/ULK1 pathway.

CONCLUSIONS

Our findings demonstrated that ICA exerts anti-cancer effects against TNBC and the associated molecular mechanisms. This study will help to facilitate further preclinical and clinical investigations for the treatment of TNBC.

PSMD2 contributes to the progression of esophageal squamous cell carcinoma by repressing autophagy

BACKGROUND

The ubiquitin-proteasome and autophagy-lysosomal systems collaborate in regulating the levels of intracellular proteins. Dysregulation of protein homeostasis is a central feature of malignancy. The gene encoding 26S proteasome non-ATPase regulatory subunit 2 (PSMD2) of the ubiquitin-proteasome system is an oncogene in various types of cancer. However, the detailed role of PSMD2 in autophagy and its relationship to tumorigenesis in esophageal squamous cell carcinoma (ESCC) remain unknown. In the present study, we have investigated the tumor-promoting roles of PSMD2 in the context of autophagy in ESCC.

METHODS

Molecular approaches including DAPgreen staining, 5-Ethynyl-2'-deoxyuridine (EdU), cell counting kit 8 (CCK8), colony formation, transwell assays, and cell transfection, xenograft model, immunoblotting and Immunohistochemical analysis were used to investigate the roles of PSMD2 in ESCC cells. Data-independent acquisition (DIA) quantification proteomics analysis and rescue experiments were used to study the roles of PSMD2 in ESCC cells.

RESULTS

We demonstrate that the overexpression of PSMD2 promotes ESCC cell growth by inhibiting autophagy and is correlated with tumor progression and poor prognosis of ESCC patients. DIA quantification proteomics analysis shows a significant positive correlation between argininosuccinate synthase 1 (ASS1) and PSMD2 levels in ESCC tumors. Further studies indicate that PSMD2 activates the mTOR pathway by upregulating ASS1 to inhibit autophagy.

CONCLUSIONS

PSMD2 plays an important role in repressing autophagy in ESCC, and represents a promising biomarker to predict prognosis and a therapeutic target of ESCC patients.

Towards dual function of autophagy in breast cancer: A potent regulator of tumor progression and therapy response

As a devastating disease, breast cancer has been responsible for decrease in life expectancy of females and its morbidity and mortality are high. Breast cancer is the most common tumor in females and its treatment has been based on employment of surgical resection, chemotherapy and radiotherapy. The changes in biological behavior of breast tumor relies on genomic and epigenetic mutations and depletions as well as dysregulation of molecular mechanisms that autophagy is among them. Autophagy function can be oncogenic in increasing tumorigenesis, and when it has pro-death function, it causes reduction in viability of tumor cells. The carcinogenic function of autophagy in breast tumor is an impediment towards effective therapy of patients, as it can cause drug resistance and radio-resistance. The important hallmarks of breast tumor such as glucose metabolism, proliferation, apoptosis and metastasis can be regulated by autophagy. Oncogenic autophagy can inhibit apoptosis, while it promotes stemness of breast tumor. Moreover, autophagy demonstrates interaction with tumor microenvironment components such as macrophages and its level can be regulated by anti-tumor compounds in breast tumor therapy. The reasons of considering autophagy in breast cancer therapy is its pleiotropic function, dual role (pro-survival and pro-death) and crosstalk with important molecular mechanisms such as apoptosis. Moreover, current review provides a pre-clinical and clinical evaluation of autophagy in breast tumor.

The Role of Autophagy in Breast Cancer Metastasis

Patient morbidity and mortality is significantly increased in metastatic breast cancer. The metastasis process of breast cancer is very complicated and is delicately controlled by various factors. Autophagy is one of the important regulatory factors affecting metastasis in breast cancer by engaging in cell mobility, metabolic adaptation, tumor dormancy, and cancer stem cells. Here, we discuss the effects of autophagy on metastasis in breast cancer and assess the potential use of autophagy modulators for metastasis treatment.

Anemoside A3 Inhibits Macrophage M2-Like Polarization to Prevent Triple-Negative Breast Cancer Metastasis

Triple negative breast cancer (TNBC) exhibits the characteristics of strong metastatic ability and a high recurrence rate, and M2-type macrophages play an important role in this process. Previous research data suggested that Anemoside A3 (A3), a monomeric component of Pulsatilla Chinensis, could prevent and treat TNBC by converting M0 macrophages into M1 immunogen phenotypes. This study showed that A3 significantly restrained the lung metastases of 4 T1-Luc cells with bioluminescence imaging in vivo and Hematoxylin and Eosin (H&E) staining. Meanwhile, the percentage of M2-type macrophages (CD206+ labeled cells) in the lung tissues was evidently decreased through immunohistochemical assay. We further proved that A3 markedly prevented M2-type polarization induced by IL-4 in vitro, as illustrated by the down-regulated expression of the cell surface marker CD206 protein by FACS and Arg-1, and of the Fizz1 and Ym1 genes by RT-PCR in M2-type macrophages. Furthermore, the invasion and migration of 4 T1 cells, which was promoted by the conditioned medium from M2-type macrophages, could be suppressed by A3. Luminex assay demonstrated that A3 treatment resulted in a reduction of the levels of CCL2, VEGF, CCL7, and MMP-9 in conditioned medium. Additionally, the expression of phosphorylated-STAT3 protein was inhibited by A3, which resulted in the macrophage M2-type polarization arrest, while no significant difference in JAK2 phosphorylation was detected. SiRNA transfection experiments suggested that STAT3 might be the target of A3 inhibiting M2-type polarization of macrophages. In conclusion, these results indicate that A3 could attenuate the metastasis of TNBC by inhibiting the M2-type polarization of macrophages, which may be related to the STAT3 pathway.

5'-tRF-GlyGCC promotes breast cancer metastasis by increasing fat mass and obesity-associated protein demethylase activity

tRNA-derived fragments (tRFs) are a class of regulatory non-coding RNAs that play essential biological functions in cancer and stress-induced diseases. Several lines of evidence suggest that 5'-tRF-GlyGCC participates in tumor progression; however, its molecular mechanisms remain unclear. In this study, we explored the function of 5'-tRF-GlyGCC in breast cancer (BC) progression and studied the related potential molecular mechanisms. 5'-tRF-GlyGCC expression increased in human BC, and it promoted the proliferation, migration, and invasion of BC cells in vitro and tumor growth and metastasis in vivo. 5'-tRF-GlyGCC was found for the first time to bind directly to fat mass and obesity-associated proteins, and increase the activity of FTO demethylase, reducing eIF4G1 methylation, inhibiting autophagy, and promoting BC proliferation and metastasis. These findings suggest that 5'-tRF-GlyGCC might be a therapeutic target for treating BC.

circRNAs and their relationship with breast cancer: a review

BACKGROUND

Recently, an increasing number of studies have been conducted on circular RNAs (circRNAs) that have demonstrated their different roles in a variety of biological processes. Moreover, a large number of circRNAs have been shown to be involved in the occurrence and development of breast cancer (BC).

MAIN BODY

Both functional and mechanistic experiments have shown that circular RNAs (circRNAs) can act as competing endogenous RNAs by sponging miRNAs, encoding proteins, and regulating parental genes. In doing so, circRNAs modulate the proliferation, migration, apoptosis, and invasion of BC cells in vitro as well as tumor growth and metastasis in vivo. Moreover, scores of circRNAs have been demonstrated to be related to clinicopathological features, prognosis, and treatment sensitivity in patients with BC; many circRNAs have shown potential as biomarkers for diagnosis, drug sensitivity, and prognosis prediction. Furthermore, researchers have focused on circRNAs as potential therapeutic targets.

CONCLUSION

In this review, we briefly summarize the functions and categories of circRNAs, their different roles in BC, and recent research and therapeutic progress related to circRNAs.

c-Myc-Regulated lncRNA-IGFBP4 Suppresses Autophagy in Cervical Cancer-Originated HeLa Cells

LncRNAs are known to regulate a plethora of key events of cellular processes; however, little is known about the function of lncRNAs in autophagy. Here in the current study, we report lncRNA-IGFBP4 which has previously been known to regulate the proliferation and reprogramming of cancer cells, but its role in autophagy is not yet known. We found that serum starvation provokes autophagy-induced downregulation of lncRNA-IGFBP4 levels. Next, we determined that c-Myc can negatively regulate lncRNA-IGFBP4 in HeLa cells. Phenotypically, we found that upon depletion of lncRNA-IGFBP4, the HeLa cells undergo autophagy through ULK1/Beclin1 signaling. Furthermore, through TCGA data analysis, we found lncRNA-IGFB4 overexpressed in most cancers including cervical cancer. Based on these findings, we conclude that c-Myc maintains cellular homeostasis through negatively regulating lncRNA-IGFBP4 in cervical cancer cells.

Matrine induces autophagy in human neuroblastoma cells via blocking the AKT-mTOR pathway

Neuroblastoma (NB) is one of the most common malignant solid tumors in children. Despite significant advances in the treatment strategy, the long-term survival rate of NB patients is only 50%. Developing new agents for NB patients deserves attention. Recent research indicates that matrine, a natural quinolizidine alkaloid component extracted from the traditional Chinese medicine Sophora root, is widely used for various diseases, including antitumor effects against a variety of cancers. However, the effect of matrine on NB is unknown. Herein, we found that matrine exerted antiproliferative activity in human NB cells in dose- and time-dependent manner. Matrine triggered autophagy in NB cells by blocking the AKT-mTOR signaling pathway and suppressing the phosphorylation of AKT and mTOR. 3-Methyladenine (3-MA), a PI3K inhibitor, protected against matrine-induced inhibition of cell proliferation, further supporting that the antitumor activity of matrine was at least partly autophagy-dependent. In vivo, matrine reduced tumor growth of SK-N-DZ cells in a dose-dependent manner. Matrine treatment significantly declined the phosphorylation of AKT and mTOR and enhanced the LC3 II/GAPDH ratio in NB xenografts. Altogether, our work uncovered the molecular mechanism underlying matrine-induced autophagy in NB and provided implications for matrine as a potential therapeutic agent against NB.

Non-Coding RNAs and Oral Cancer: Small Molecules With Big Functions

Oral cancer remains a major public concern with considerable socioeconomic impact in the world. Despite substantial advancements have been made in treating oral cancer, the five-year survival rate for oral cancer remained undesirable, and the molecular mechanisms underlying OSCC carcinogenesis have not been fully understood. Noncoding RNAs (ncRNAs) include transfer RNAs (tRNAs), as well as small RNAs such as microRNAs, and the long ncRNAs such as HOTAIR are a large segment of the transcriptome that do not have apparent protein-coding roles, but they have been verified to play important roles in diverse biological processes, including cancer cell development. Cell death, such as apoptosis, necrosis, and autophagy, plays a vital role in the progression of cancer. A better understanding of the regulatory relationships between ncRNAs and these various types of cancer cell death is therefore urgently required. The occurrence and development of oral cancer can be controlled by increasing or decreasing the expression of ncRNAs, a method which confers broad prospects for oral cancer treatment. Therefore, it is urgent for us to understand the influence of ncRNAs on the development of different modes of oral tumor death, and to evaluate whether ncRNAs have the potential to be used as biological targets for inducing cell death and recurrence of chemotherapy. The purpose of this review is to describe the impact of ncRNAs on cell apoptosis and autophagy in oral cancer in order to explore potential targets for oral cancer therapy.

Targeting regulated cell death (RCD) with small-molecule compounds in triple-negative breast cancer: a revisited perspective from molecular mechanisms to targeted therapies

Triple-negative breast cancer (TNBC) is a subtype of human breast cancer with one of the worst prognoses, with no targeted therapeutic strategies currently available. Regulated cell death (RCD), also known as programmed cell death (PCD), has been widely reported to have numerous links to the progression and therapy of many types of human cancer. Of note, RCD can be divided into numerous different subroutines, including autophagy-dependent cell death, apoptosis, mitotic catastrophe, necroptosis, ferroptosis, pyroptosis and anoikis. More recently, targeting the subroutines of RCD with small-molecule compounds has been emerging as a promising therapeutic strategy, which has rapidly progressed in the treatment of TNBC. Therefore, in this review, we focus on summarizing the molecular mechanisms of the above-mentioned seven major RCD subroutines related to TNBC and the latest progress of small-molecule compounds targeting different RCD subroutines. Moreover, we further discuss the combined strategies of one drug (e.g., narciclasine) or more drugs (e.g., torin-1 combined with chloroquine) to achieve the therapeutic potential on TNBC by regulating RCD subroutines. More importantly, we demonstrate several small-molecule compounds (e.g., ONC201 and NCT03733119) by targeting the subroutines of RCD in TNBC clinical trials. Taken together, these findings will provide a clue on illuminating more actionable low-hanging-fruit druggable targets and candidate small-molecule drugs for potential RCD-related TNBC therapies.

Autophagy and cancer treatment: four functional forms of autophagy and their therapeutic applications

Cancer is the leading cause of death worldwide. Drugs play a pivotal role in cancer treatment, but the complex biological processes of cancer cells seriously limit the efficacy of various anticancer drugs. Autophagy, a self-degradative system that maintains cellular homeostasis, universally operates under normal and stress conditions in cancer cells. The roles of autophagy in cancer treatment are still controversial because both stimulation and inhibition of autophagy have been reported to enhance the effects of anticancer drugs. Thus, the important question arises as to whether we should try to strengthen or suppress autophagy during cancer therapy. Currently, autophagy can be divided into four main forms according to its different functions during cancer treatment: cytoprotective (cell survival), cytotoxic (cell death), cytostatic (growth arrest), and nonprotective (no contribution to cell death or survival). In addition, various cell death modes, such as apoptosis, necrosis, ferroptosis, senescence, and mitotic catastrophe, all contribute to the anticancer effects of drugs. The interaction between autophagy and these cell death modes is complex and can lead to anticancer drugs having different or even completely opposite effects on treatment. Therefore, it is important to understand the underlying contexts in which autophagy inhibition or activation will be beneficial or detrimental. That is, appropriate therapeutic strategies should be adopted in light of the different functions of autophagy. This review provides an overview of recent insights into the evolving relationship between autophagy and cancer treatment.

Autophagy related long non-coding RNA and breast cancer prognosis analysis and prognostic risk model establishment

Background

The role of autophagy-related long-stranded non-coding RNA (lncRNA) in breast cancer (BRCA) is unclear. We proposed to screen autophagy-related lncRNAs in BRCA and construct a prognostic risk assessment model to explore prognostic correlates.

Methods

We extracted BRCA lncRNAs from The Cancer Genome Atlas (TCGA) database and autophagy-related genes from the Human Autophagy Database (HADb), to screen for autophagy-related lncRNA pairs (ARLP) in BRCA. Single-factor Cox regression analysis and multi-factor Cox regression analysis were used to screen lncRNAs associated with BRCA prognosis, and risk models were established. We divided BRCA patients into high-risk and low-risk groups based on median risk scores. The single-sample gene set enrichment analysis (ssGSEA) algorithm was used to calculate the abundance of 28 immune cells in the TCGA-BRCA cohort and to analyze the relationship between the risk score and the level of immune cell infiltration by ARLP characteristics.

Results

Univariate Cox regression results showed that 42 ARLPs were significantly associated with overall survival (OS) in BRCA patients. Further multifactorial analysis showed that a total of 11 lncRNAs, including SEMA3B-AS1, ST7-AS1, AL136295.7, AC090912.1, LINC01871, AL136531.1, AC024361.1, OTUD6B-AS1, LINC01786, AL122010.1, and MAPT-AS1, were prognostically independent influencers of BRCA. The risk model developed was further validated as a new independent prognostic factor for BRCA patients by Kaplan-Meier (KM) analysis, univariate and multivariate Cox regression analysis to calculate the risk score. In addition, the results of the relationship between risk score and immune infiltration showed that low risk score was associated with T-lymphocyte subpopulation.

Conclusions

Our study suggested that a risk model consisting of 11 autophagy-related lncRNAs can be used to assess the prognosis of BRCA patients.

Myricetin Induces Autophagy and Cell Cycle Arrest of HCC by Inhibiting MARCH1-Regulated Stat3 and p38 MAPK Signaling Pathways

Myricetin is a type of natural flavonol known for its anticancer activity. However, the molecular mechanism of myricetin in anti-hepatocellular carcinoma (HCC) is not well defined. Previous studies indicated that downregulation of membrane-associated RING-CH finger protein 1 (MARCH1) contributed to the treatment of a variety of cancers. Whether the anticancer property of myricetin is associated with MARCH1 expression remains to be investigated. This research explored the anti-HCC mechanism of myricetin. Our results indicate that myricetin induces autophagy and arrests cell cycle at the G2/M phase to suppress the proliferation of HCC cells by downregulating MARCH1. Myricetin reduces MARCH1 protein in Hep3B and HepG2 cells. Interestingly, myricetin upregulates the MARCH1 mRNA level in Hep3B cells but downregulates it in HepG2 cells. The knockdown of MARCH1 by siRNAs (small interfering RNAs) decreases the phosphorylated p38 MAPK (p-p38 MAPK) and Stat3 (p-Stat3), and inhibits HCC cell viability. Moreover, myricetin inhibits p38 MAPK and Stat3 signaling pathways by downregulating MARCH1 to repress HCC growth both in vitro and in vivo. Bafilomycin A1 (BafA1), an autophagy inhibitor, has synergetic effect with myricetin to inhibit HCC growth. Taken together, our results reveal that myricetin inhibits the proliferation of HCC cells by inhibiting MARCH1-regulated p38 MAPK and Stat3 signaling pathways. This research provides a new molecular mechanism for myricetin in anti-HCC and suggests that targeting MARCH1 could be a novel treatment strategy in developing anticancer therapeutics.

Let-7e modulates the proliferation and the autophagy of human granulosa cells by suppressing p21 signaling pathway in polycystic ovary syndrome without hyperandrogenism

Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder in reproductive-aged women, and its pathogenesis is still under debate. Recent studies suggest crucial roles for microRNAs (miRNAs) in PCOS development. The let-7 family miRNAs constitute the most abundant miRNAs in human granulosa cells (GCs), and plays an important role in follicular development. However, research on the let-7e implications of the non-hyperandrogenic (non-HA) phenotype remains unclear. This study aimed at determining the role of let-7e in the progression of PCOS. We performed quantitative real-time PCR to examine the levels of let-7e in fifty-two non-HA PCOS patients and fifty-two controls. A receiver operating characteristic (ROC) curve were used to reveal the diagnostic value of let-7e in non-HA PCOS. Using an immortalized human granulosa cell line, KGN, we investigated the influence of let-7e on cell proliferation and autophagy. Our data substantiated the expression of let-7e was significantly increased in non-HA PCOS group, and associated with an increased antral follicle count. The ROC curve indicated a major separation between non-HA PCOS group and the control group. Let-7e knockdown suppressed cell proliferation and enhanced cell autophagy by activating p21 pathway. Conversely, let-7e overexpression promoted cell proliferation and inhibited cell autophagy by suppressing p21 pathway. Our results indicate that increased let-7e levels in non-HA PCOS GCs may contribute to excessive follicular activation and growth, thereby involving in the pathogenesis of PCOS. Let-7e may thus be a potential therapeutic target in non-HA PCOS.

Small Molecules Targeting Programmed Cell Death in Breast Cancer Cells

Targeted chemotherapy has become the forefront for cancer treatment in recent years. The selective and specific features allow more effective treatment with reduced side effects. Most targeted therapies, which include small molecules, act on specific molecular targets that are altered in tumour cells, mainly in cancers such as breast, lung, colorectal, lymphoma and leukaemia. With the recent exponential progress in drug development, programmed cell death, which includes apoptosis and autophagy, has become a promising therapeutic target. The research in identifying effective small molecules that target compensatory mechanisms in tumour cells alleviates the emergence of drug resistance. Due to the heterogenous nature of breast cancer, various attempts were made to overcome chemoresistance. Amongst breast cancers, triple negative breast cancer (TNBC) is of particular interest due to its heterogeneous nature in response to chemotherapy. TNBC represents approximately 15% of all breast tumours, however, and still has a poor prognosis. Unlike other breast tumours, signature targets lack for TNBCs, causing high morbidity and mortality. This review highlights several small molecules with promising preclinical data that target autophagy and apoptosis to induce cell death in TNBC cells.

Repression of the AURKA-CXCL5 axis induces autophagic cell death and promotes radiosensitivity in non-small-cell lung cancer

Aurora kinase A (AURKA) regulates apoptosis and autophagy in various diseases and has shown promising clinical effects. Nevertheless, the complex regulatory mechanism of AURKA and autophagy in non-small-cell lung cancer (NSCLC) radiosensitivity remains to be elucidated. Here, we showed that AURKA was upregulated in NSCLC cell lines and tissues and that AURKA overexpression was significantly related to a poor prognosis, tumor stage and lymph node metastasis in NSCLC. Interestingly, AURKA expression was significantly increased after 8Gy radiotherapy. Silencing of AURKA enhanced radiosensitivity and impaired migration and invasion in vivo and in vitro. Mechanistically, we determined that CXCL5, a member of the chemokine family, was a key downstream effector of AURKA, and the phenotype induced by AURKA silencing was partly due to CXCL5 inhibition. We further demonstrated that the AURKA-CXCL5 axis played an essential role in NSCLC autophagy and that the activation of cytotoxic autophagy attenuated the malignant biological behavior of NSCLC cells mediated by AURKA-CXCL5. In general, we revealed the role of the AURKA-CXCL5 axis and autophagy in regulating the sensitivity of NSCLC cells to radiotherapy, which may provide potential therapeutic targets and new strategies for combatting NSCLC resistance to radiotherapy.

Endoplasmic reticulum stress manipulates autophagic response that antagonizes polybrominated diphenyl ethers quinone induced cytotoxicity in microglial BV2 cells

Polybrominated diphenyl ethers (PBDEs) were widely used as flame retardants. Previously, we reported that their quinone-type metabolite (PBDEQ) induced selective autophagy, but its biological consequences remain obscure. Here, we illustrated the possible link of PBDEQ-induced autophagy with endoplasmic reticulum (ER) stress and cytotoxicity in microglial BV2 cells. We found PBDEQ increased the formation of autophagosomes, promoted autophagic degradation, suggesting an improved autophagy flux in BV2 cells. Interestingly, both pharmacologic autophagy inhibitors and autophagy-related 5 gene small interfering RNA (ATG5 siRNA) aggravated the cytotoxicity of PBDEQ, suggesting the antagonizing role of autophagy. PBDEQ induced ER stress and activated protein kinase R-like ER kinase (PERK)-eukaryotic translation initiation factor 2α (eIF2α)-activating transcription factor 4 (ATF4)-C/EBP homologous protein (CHOP) axis of classic unfolded protein response (UPR) pathway, whilst ER stress inhibitor blocked PBDEQ-induced autophagy. Moreover, N-acetyl-L-cysteine (NAC) alleviated PBDEQ-induced activation of ER stress and autophagy, suggesting reactive oxygen species (ROS) were involved in regulating PBDEQ-induced ER stress and autophagy. Taken together, our results demonstrate a new mechanism of PBDEQ-associated toxicity.

A novel autophagy-related genes prognostic risk model and validation of autophagy-related oncogene VPS35 in breast cancer

BACKGROUND

Accumulating evidence implies that autophagy plays a critical role in breast cancer development and progression. It is crucial to screen out autophagy-related encoding genes (ARGs) with prognostic value in breast cancer and reveal their biological properties in the aggressiveness of breast cancer.

METHODS

Univariate and multivariate Cox proportional hazards analyses were used to identify a prognostic risk model of ARGs from The Cancer Genome Atlas (TCGA). Kaplan-Meier analysis, univariate and multivariate Cox regression analyses and receiver operating characteristic (ROC) curve analysis were performed to validate the risk model. Western blot and immunohistochemistry (IHC) were conducted to assess the expression of VPS35 (one of ARGs in risk model). CCK8, Colony formation assay, Transwell migration/invasion assays and autophagy flux assay were used to confirm biological function of VPS35 in breast cancer.

RESULTS

In this study, the prognostic risk model consisting of six ARGs (VPS35, TRIM21, PRKAB2, RUFY4, MAP1LC3A and LARP1) in breast cancer were identified. The risk model was further verified as a novel independent prognostic factor for breast cancer patients. We also clarified that vacuolar protein sorting-associated protein 35 (VPS35), one of ARGs in the risk model, was upregulated in breast cancer samples and cell lines. VPS35 overexpression was correlated with more aggressive phenotype of breast cancer and indicated worse prognosis in both progression-free survival and overall survival analyses. Meanwhile, VPS35 knockdown inhibited breast cancer cell proliferation, migration and invasion, suggesting that VPS35 promoted the progression of breast cancer. VPS35 silence also influenced autophagy process, indicating that VPS35 was essential for autophagy completion.

CONCLUSION

Taken together, the six ARGs risk model has a remarkably prognostic value for breast cancer. Among them, VPS35 might exert as a significant oncogenic and prognostic factor for breast cancer and could be a promising autophagy-related therapeutic target in clinical practice.

Natural products as geroprotectors: An autophagy perspective

Over the past decade, significant attention has been given to repurposing Food and Drug Administration approved drugs to treat age-related diseases. In contrast, less consideration has been given to natural bioactive compounds. Consequently, there have been limited attempts to translate these compounds. Autophagy is a fundamental biological pathway linked to aging, and numerous strategies to enhance autophagy have been shown to extend lifespan. Interestingly, there are a number of natural products that are reported to modulate autophagy, and here we describe a number of them that activate autophagy through diverse molecular and cellular mechanisms. Among these, Urolithin A, Spermidine, Resveratrol, Fatty Acids and Phospholipids, Trehalose and Lithium are featured in detail. Finally, we outline possible strategies to optimise and increase the translatability of natural products, with the overall aim of delaying the ageing process and improving human healthspan.

LINCS gene expression signature analysis revealed bosutinib as a radiosensitizer of breast cancer cells by targeting eIF4G1

Radioresistance is the predominant cause for radiotherapy failure and disease progression, resulting in increased breast cancer‑associated mortality. Using gene expression signature analysis of the Library of Integrated Network‑Based Cellular Signatures (LINCS) and Gene Expression Omnibus (GEO), the aim of the present study was to systematically identify potential candidate radiosensitizers from known drugs. The similarity of integrated gene expression signatures between irradiated eukaryotic translation initiation factor 4 γ 1 (eIF4G1)‑silenced breast cancer cells and known drugs was measured using enrichment scores (ES). Drugs with positive ES were selected as potential radiosensitizers. The radiosensitizing effects of the candidate drugs were analyzed in breast cancer cell lines (MCF‑7, MX‑1 and MDA‑MB‑231) using CCK‑8 and colony formation assays following exposure to ionizing radiation. Cell apoptosis was measured using flow cytometry. The expression levels of eIF4G1 and DNA damage response (DDR) proteins were analyzed by western blotting. Bosutinib was identified as a promising radiosensitizer, as its administration markedly reduced the dosage required both for the drug and for ionizing radiation, which may be associated with fewer treatment‑associated adverse reactions. Moreover, combined treatment of ionizing radiation and bosutinib significantly increased cell killing in all three cell lines, compared with ionizing radiation or bosutinib alone. Among the three cell lines, MX‑1 cells were identified as the most sensitive to both ionizing radiation and bosutinib. Bosutinib markedly downregulated the expression of eIF4G1 in a dose‑dependent manner and also reduced the expression of DDR proteins (including ATM, XRCC4, ATRIP, and GADD45A). Moreover, eIF4G1 was identified as a key target of bosutinib that may regulate DNA damage induced by ionizing radiation. Thus, bosutinib may serve as a potential candidate radiosensitizer for breast cancer therapy.

Chemopreventive and Anticancer Property of Selenoproteins in Obese Breast Cancer

Obesity is a significant risk factor for various cancers including breast cancer resulting in an increased risk of recurrence as well as morbidity and mortality. Extensive studies on various pathways have been successful in establishing a biological relationship between obesity and breast cancer. The molecular classification of breast cancer includes five groups each having different responses to treatment. Increased levels of inflammatory cytokines seen in obese conditions drive the pro-proliferative pathways, such as the influx of macrophages, angiogenesis, and antiapoptotic pathways. Increased peripheral aromatization of androgens by aromatase increases the circulating estrogen levels which are also responsible for the association of obesity with breast cancer. Also, increased oxidative stress due to chronic low-grade inflammation in obese women plays an important role in carcinogenesis. Despite the availability of safe and effective treatment options for breast cancer, obese women are at increased risk of adverse outcomes including treatment-related toxicities. In the recent decade, selenium compounds have gained substantial interest as chemopreventive and anticancer agents. The chemical derivatives of selenium include inorganic and organic compounds that exhibit pro-oxidant properties and alter cellular redox homeostasis. They target more than one metabolic pathway by thiol modifications, induction of reactive oxygen species, and chromatin modifications to exert their chemopreventive and anticancer activities. The primary functional effectors of selenium that play a significant role in human homeostasis are selenoproteins like glutathione peroxidase, thioredoxin reductase, iodothyronine deiodinases, and selenoprotein P. Selenoproteins play a significant role in adipose tissue physiology by modulating preadipocyte proliferation and adipogenic differentiation. They correlate negatively with body mass index resulting in increased oxidative stress that may lead to carcinogenesis in obese individuals. Methylseleninic acid effectively suppresses aromatase activation thus reducing the estrogen levels and acting as a breast cancer chemopreventive agent. Adipose-derived inflammatory mediators influence the selenium metabolites and affect the proliferation and metastatic properties of cancer cells. Recently selenium nanoparticles have shown potent anticancer activity which may lead to a major breakthrough in the management of cancers caused due to multiple pathways. In this review, we discuss the possible role of selenoproteins as chemopreventive and an anticancer agent in obese breast cancer.

Identification and optimization of 3-bromo-N'-(4-hydroxybenzylidene)-4-methylbenzohydrazide derivatives as mTOR inhibitors that induce autophagic cell death and apoptosis in triple-negative breast cancer

Triple negative breast cancer (TNBC) has a worse prognosis than other types of breast cancer due to its special biological behavior and clinicopathological characteristics. TNBC cell proliferation and progression to metastasis can be suppressed by inducing cytostatic autophagy. mTOR is closely related to autophagy and is involved in protein synthesis, nutrient metabolism and activating mTOR promotes tumor growth and metastasis. In this paper, we adopted the strategy of structure simplification, aimed to look for novel small-molecule inhibitors of mTOR by pharmacophore-based virtual screening and biological activity determination. We found a lead compound with 3-bromo-N'-(4-hydroxybenzylidene)-4-methylbenzohydrazide for rational drug design and structural modification, then studied its structure-activity relationship. After that, compound 7c with the best TNBC cells inhibitory activities and superior mTOR enzyme inhibitory activity was obtained. In addition, we found that compound 7c could induce autophagic cell death and apoptosis in MDA-MB-231 and MDA-MB-468 cell lines. In conclusion, these findings provide new clues for our 3-bromo-N'-(4-hydroxybenzylidene)-4-methylbenzohydrazide derivatives, which are expected to become drug candidates for the treatment of TNBC in the future.

New Insight into Triple-Negative Breast Cancer Therapy: The Potential Roles of Endoplasmic Reticulum Stress and Autophagy Mechanisms

BACKGROUND

Breast cancer is accounted as the fifth leading cause of mortality among the other cancers. Notwithstanding, Triple Negative Breast Cancer (TNBC) is responsible for 15-20% of breast cancer mortality. Despite many investigations, it remains incurable in part due to insufficient understanding of its exact mechanisms.

METHODS

A literature search was performed in PubMed, SCOPUS and Web of Science databases using the keywords autophagy, Endoplasmic Reticulum (ER) stress, apoptosis, TNBC and the combinations of these keywords.

RESULTS

It was found that autophagy plays a dual role in cancer, so that it may decrease the viability of tumor cells or act as a cytoprotective mechanism. It then appears that using compounds having modulatory effects on autophagy is of importance in terms of induction of autophagic cell death and diminishing the proliferation and metastasis of tumor cells. Also, ER stress can be modulated in order to stimulate apoptotic and autophagic cell death in tumor cells.

CONCLUSION

Perturbation in the signaling pathways related to cell survival leads to the initiation and progression of cancer. Regarding the advancement in the cancer pathology, it seems that modulation of autophagy and ER stress are promising.

A novel autophagy-related lncRNA prognostic risk model for breast cancer

Long non-coding RNAs (lncRNAs) are well known as crucial regulators to breast cancer development and are implicated in controlling autophagy. LncRNAs are also emerging as valuable prognostic factors for breast cancer patients. It is critical to identify autophagy-related lncRNAs with prognostic value in breast cancer. In this study, we identified autophagy-related lncRNAs in breast cancer by constructing a co-expression network of autophagy-related mRNAs-lncRNAs from The Cancer Genome Atlas (TCGA). We evaluated the prognostic value of these autophagy-related lncRNAs by univariate and multivariate Cox proportional hazards analyses and eventually obtained a prognostic risk model consisting of 11 autophagy-related lncRNAs (U62317.4, LINC01016, LINC02166, C6orf99, LINC00992, BAIAP2-DT, AC245297.3, AC090912.1, Z68871.1, LINC00578 and LINC01871). The risk model was further validated as a novel independent prognostic factor for breast cancer patients based on the calculated risk score by Kaplan-Meier analysis, univariate and multivariate Cox regression analyses and time-dependent receiver operating characteristic (ROC) curve analysis. Moreover, based on the risk model, the low-risk and high-risk groups displayed different autophagy and oncogenic statues by principal component analysis (PCA) and Gene Set Enrichment Analysis (GSEA) functional annotation. Taken together, these findings suggested that the risk model of the 11 autophagy-related lncRNAs has significant prognostic value for breast cancer and might be autophagy-related therapeutic targets in clinical practice.

Therapeutic potential of IBP as an autophagy inducer for treating lung cancer via blocking PAK1/Akt/mTOR signaling

Lung cancer is the most frequent and fatal malignancy in humans worldwide, yet novel successful drugs for control of this disease are still lacking. Ipomoea batatas polysaccharides (IBPs) have been implicated in inhibiting diverse cancer types, but their functions in mitigating lung cancer are largely unknown. In this study, we identify a role of IBP in inhibiting lung cancer proliferation. We found that IBP significantly impedes the proliferation of lung cancer cells by inducing cytostatic macroautophagy both in vitro and in vivo. Mechanistically, IBP specifically promotes ubiquitination-mediated degradation of PAK1 (p21-activated kinase 1) and blocks its downstream Akt1/mTOR signaling pathway, leading to increased autophagic flux. In lung cancer xenografts in mice, IBP-induced cytostatic autophagy suppresses tumor development. Through site-directed mutational analysis, the underlying signaling augments ubiquitination via PAK1-ubiquitin interaction. Collectively, this work unravels the molecular mechanism underpinning IBP-induced cytostatic autophagy in lung cancer and characterizes IBP as a potential therapeutic agent for lung cancer treatment.

Flubendazole elicits anti-cancer effects via targeting EVA1A-modulated autophagy and apoptosis in Triple-negative Breast Cancer

Background: Triple-negative breast cancer (TNBC) is one of the most prevalent neoplastic diseases worldwide, but efficacious treatments for this pathological condition are still challenging. The lack of an effective targeted therapy also leads to a poor prognosis for patients affected by TNBC. In the present study, we repurposed the distinctive inhibitory effects of flubendazole, a traditional anthelmintic drug, towards the putative modulation of proliferation and migration of TNBC in vitro and in vivo.

Methods: According to a series of experimental approaches, including immunofluorescence (IF), immunoblotting (IB), siRNA and GFP-mRFP-LC3 plasmid transfection, respectively, we have found that flubendazole is capable of inducing autophagic cell death and apoptosis, thus exerting some anti-proliferative and anti-migration activity in TNBC cells. The therapeutic effects of flubendazole were evaluated by xenograft mouse models, followed by immunohistochemistry (IHC), IF and IB. Changes in the gene expression profiles of flubendazole-treated TNBC cells were analyzed by RNA sequencing (RNA-seq) and validated by IB. The potential binding mode of flubendazole and EVA1A was predicted by molecular docking and demonstrated by site-directed mutagenesis.

Results: We have presently found that flubendazole exhibits a considerable anti-proliferative activity in vitro and in vivo. Mechanistically, the induction of autophagic cell death appears to be pivotal for flubendazole-mediated growth inhibition of TNBC cells, whereas blocking autophagy was able to improve the survival rate and migration ability of flubendazole-treated TNBC cells. Specifically, RNA-seq analysis showed that flubendazole treatment could promote the up-regulation of EVA1A. Flubendazole may regulate autophagy and apoptosis by targeting EVA1A, thus affecting the mechanisms of TNBC proliferation and migration. Furthermore, Thr113 may be the key amino acid residues for the binding of flubendazole to EVA1A.

Conclusion: Our results provide novel insights towards the putative anti-cancer efficacy of flubendazole. Furthermore, here we show that flubendazole could serve as a potential therapeutic drug in TNBC. Altogether, this study highlights the possibility of this repurposed autophagic inducer for future cancer treatments.

The Gαh/phospholipase C-δ1 interaction promotes autophagosome degradation by activating the Akt/mTORC1 pathway in metastatic triple-negative breast cancer

Lung metastasis (LM) is commonly found in triple-negative breast cancer (TNBC); however, the molecular mechanism underlying TNBC metastasis to lungs remains largely unknown. We thus aimed to uncover a possible mechanism for the LM of TNBC. Here we show that the phosphorylation of Akt and mTORC1 was positively but the autophagy activity was negatively correlated with endogenous Gαh levels and cell invasion ability in TNBC cell lines. Whereas the knockdown of Gαh, as well as blocking its binding with PLC-δ1 by a synthetic peptide inhibitor, in the highly invasive MDA-MB231 cells dramatically suppressed Akt/mTORC1 phosphorylation and blocked autophagosome degradation, the overexpression of Gαh in the poorly invasive HCC1806 cells enhanced Akt/mTORC1 phosphorylation but promoted autophagosome degradation. The pharmaceutical inhibition of autophagy initiation by 3-methyladenine was found to rescue the cell invasion ability and LM potential of Gαh-silenced MDA-MB231 cells. In contrast, the inhibition of mTORC1 activity by rapamycin suppressed autophagosome degradation but mitigated the cell invasion ability and LM potential of Gαh-overexpressing HCC1806 cells. These findings demonstrate that the induction of autophagy activity or the inhibition of Akt-mTORC1 axis provides a useful strategy to combat the Gαh/PLC-δ1-driven LM of TNBC.

Role of autophagy in regulation of cancer cell death/apoptosis during anti-cancer therapy: focus on autophagy flux blockade

Autophagy is a self-degradation process in which the cytoplasmic cargoes are delivered to the lysosomes for degradation. As the cargoes are degraded/recycled, the autophagy process maintains the cellular homeostasis. Anti-cancer therapies induce apoptosis and autophagy concomitantly, and the induced autophagy normally prevents stress responses that are being induced. In such cases, the inhibition of autophagy can be a reasonable strategy to enhance the efficacy of anti-cancer therapies. However, recent studies have shown that autophagy induced by anti-cancer drugs causes cell death/apoptosis induction, indicating a controversial role of autophagy in cancer cell survival or death/apoptosis. Therefore, in the present review, we aimed to assess the signaling mechanisms involved in autophagy and cell death/apoptosis induction during anti-cancer therapies. This review summarizes the process of autophagy, autophagy flux and its blockade, and measurement and interpretation of autophagy flux. Further, it describes the signaling pathways involved in the blockade of autophagy flux and the role of signaling molecules accumulated by autophagy blockade in cell death/apoptosis in various cancer cells during anti-cancer therapies. Altogether, it implies that factors such as types of cancer, drug therapies, and characteristics of autophagy should be evaluated before targeting autophagy for cancer treatment.

Targeted tumor therapy by autophagy of nanoparticles

Autophagy is an important biological mechanism that regulates the growth, death and energy metabolism of eukaryotic cells. It is also an active and evolutionarily conservative catabolic process to maintain homeostasis during cell stress response and cell survival. Autophagy maintains the body’s stability by degrading damaged proteins, organelles, cytoplasm and invasive microorganisms. Studies have found that autophagy also has a significant impact on the occurrence and development of tumors. Simultaneously, nanoparticles (NPs) can induce autophagy in cells, and the level of autophagy can be regulated by the synthesis design of NPs. Therefore, the study of the regulation of autophagy by NPs is of great significance for the treatment of cancer autocorrelation.

Autophagy-associated circRNA circCDYL augments autophagy and promotes breast cancer progression

BACKGROUND

Although both circular RNAs (circRNAs) and autophagy are associated with the function of breast cancer (BC), whether circRNAs regulate BC progression via autophagy remains unknown. In this study, we aim to explore the regulatory mechanisms and the clinical significance of autophagy-associated circRNAs in BC.

METHODS

Autophagy associated circRNAs were screened by circRNAs deep sequencing and validated by qRT-PCR in BC tissues with high- and low- autophagic level. The biological function of autophagy associated circRNAs were assessed by plate colony formation, cell viability, transwells, flow cytometry and orthotopic animal models. For mechanistic study, RNA immunoprecipitation, circRNAs pull-down, Dual luciferase report assay, Western Blot, Immunofluorescence and Immunohistochemical staining were performed.

RESULTS

An autophagy associated circRNA circCDYL was elevated by 3.2 folds in BC tissues as compared with the adjacent non-cancerous tissues, and circCDYL promoted autophagic level in BC cells via the miR-1275-ATG7/ULK1 axis; Moreover, circCDYL enhanced the malignant progression of BC cells in vitro and in vivo. Clinically, increased circCDYL in the tumor tissues and serum of BC patients was associated with higher tumor burden, shorter survival and poorer clinical response to therapy.

CONCLUSIONS

circCDYL promotes BC progression via the miR-1275-ATG7/ULK1-autophagic axis and circCDYL could act as a potential prognostic and predictive molecule for breast cancer patients.

A Review of ULK1-Mediated Autophagy in Drug Resistance of Cancer

The difficulty of early diagnosis and the development of drug resistance are two major barriers to the successful treatment of cancer. Autophagy plays a crucial role in several cellular functions, and its dysregulation is associated with both tumorigenesis and drug resistance. Unc-51-like kinase 1 (ULK1) is a serine/threonine kinase that participates in the initiation of autophagy. Many studies have indicated that compounds that directly or indirectly target ULK1 could be used for tumor therapy. However, reports of the therapeutic effects of these compounds have come to conflicting conclusions. In this work, we reviewed recent studies related to the effects of ULK1 on the regulation of autophagy and the development of drug resistance in cancers, with the aim of clarifying the mechanistic underpinnings of this therapeutic target.

AURKA Enhances Autophagy of Adipose Derived Stem Cells to Promote Diabetic Wound Repair via Targeting FOXO3a

AURKA regulates apoptosis and autophagy in a diverse range of diseases and exhibits promising clinical efficacy; however, the role of AURKA in regulating adipose-derived stem cells (ADSCs) and repairing diabetic wound remains unclear. Here, we showed that ADSCs subjected to high glucose stress displayed an obvious induction of AURKA and FOXO3a, and a significant increase in autophagy and apoptosis. AURKA was confirmed to regulate autophagy through FOXO3a. AURKA-mediated autophagy inhibited high-glucose-induced apoptosis of ADSCs. Furthermore, co-immunoprecipitation and chromatin immunoprecipitation assays were employed to investigate the interaction of AURKA and FOXO3a. FOXO3a bound to its own promoter and transactivated its own expression. AURKA was found to interact with FOXO3a to regulate FOXO3a activity. In diabetic mice, ADSCs overexpressing AURKA led to a decrease of apoptosis of ADSCs and promoted wound healing in the skin. Taken together, our data suggest that transcriptional regulation of FOXO3a by high-glucose-mediated AURKA is necessary for ADSCs autophagy. Our data reveal a potential therapeutic strategy for targeting AURKA involved in high-glucose-induced anti-apoptotic autophagy in ADSCs.

Development of prognostic index based on autophagy-related genes analysis in breast cancer

BACKGROUND

Autophagy is a self-digesting process that can satisfy the metabolic needs of cells, and is closely related to development of cancer. However, the effect of autophagy-related genes (ARGs) on the prognosis of breast cancer remains unclear.

RESULTS

We first found that 27 ARGs were significantly associated with overall survival in breast cancer. The prognosis-related ARGs signature established using the Cox regression model consists of 12 ARGs that can be divided patients into high-risk and low-risk groups. The overall survival of patients with high-risk scores (HR 3.652, 2.410-5.533; P < 0.001) was shorter than patients with low-risk scores. The area under the receiver operating characteristic (ROC) curve for 1-year, 3-year, and 5-year survival rates were 0.739, 0.727, and 0.742, respectively.

CONCLUSION

The12-ARGs marker can predict the prognosis of breast cancer and thus help individualized treatment of patients at different risks.

METHODS

Based on the TCGA dataset, we integrated the expression profiles of ARGs in 1,039 breast cancer patients. Differentially expressed ARGs and survival-related ARGs were evaluated by computational difference algorithm and COX regression analysis. In addition, we also explored the mutations in these ARGs. A new prognostic indicator based on ARGs was developed using multivariate COX analysis.

XIAOPI formula promotes breast cancer chemosensitivity via inhibiting CXCL1/HMGB1-mediated autophagy

XIAOPI formula is a national approved drug prescribed to patients with high breast cancer risk. Previously we demonstrated that XIAOPI formula could inhibit breast cancer metastasis via suppressing CXCL1 expression, and postulated that "autophagy in cancer" might be one of its most core anti-cancer mechanisms. However, whether XIAOPI formula could be simultaneously applied with chemodrugs and their synergistic mechanisms are still remained unknown. In the present study, XIAOPI formula at non-cytotoxic doses could synergistically enhance the chemosensitivity of breast cancer cells MDA-MB-231 and MCF-7. We found that rapamycin-induced autophagy could reduce the chemosensitivity of breast cancer cells to XIAOPI formula, and the autophagy suppression and chemosensitizing activity of this formula was CXCL1-dependent. The evidence came from that XIAOPI formula was associated with a lower expression of CXCL1 combined with either rapamycin or taxol alone. Besides, the inhibitory effect of XIAOPI formula on the LC3-II and ABCG2 signals was weakened following CXCL1 over-expression, whereas P62 upregulation induced by XIAOPI formula was re-declined. A high throughput - qPCR (HT-qPCR) assay identified HMGB1 as the main autophagic target of XIAOPI formula in chemosensitizing breast cancer. and furhter validation suggested XIAOPI formula exerted chemosensitivity mainly via CXCL1/HMGB1 autophagic axis. Finally, we generated both mice and zebrafish xenotransplantation models bearing MDA-MB-231 breast cancer cells, and found that XIAOPI formula safely enhanced in vivo taxol chemosensitivity on breast cancer. Taken together, XIAOPI formula is a potential adjuvant drug via inhibiting CXCL1/HMGB1-mediated autophagy for breast cancer treatment with good safety.

CircCDR1as upregulates autophagy under hypoxia to promote tumor cell survival via AKT/ERK½/mTOR signaling pathways in oral squamous cell carcinomas

Autophagy, as an important non-selective degradation mechanism, could promote tumor initiation and progression by maintaining cellular homeostasis and the cell metabolism as well as cell viability. CircCDR1as has been shown to function as an oncogene in cancer progression, however, it remains largely unknown as to how autophagy is regulated by circCDR1as in oral squamous cell carcinoma (OSCC). In this study, we validated the functional roles of circCDR1as in regulation of autophagy in OSCC cells and further investigated how circCDR1as contributed to cell survival via up-regulating autophagy under a hypoxic microenvironment by using combination of human tissue model, in vitro cell experiments and in vivo mice model. We found that hypoxia promoted the expression level of circCDR1as in OSCC cells and elevated autophagy. In addition, circCDR1as further increased hypoxia-mediated autophagy by targeting multiple key regulators of autophagy. We revealed that circCDR1as enhanced autophagy in OSCC cells via inhibition of rapamycin (mTOR) activity and upregulation of AKT and ERK_½ pathways. Overexpression of circCDR1as enhanced OSCC cells viability, endoplasmic reticulum (ER) stress, and inhibited cell apoptosis under a hypoxic microenvironment. Moreover, circCDR1as promoted autophagy in OSCC cells by sponging miR-671-5p. Collectively, these results revealed that high expression of circCDR1as enhanced the viability of OSCC cells under a hypoxic microenvironment by promoting autophagy, suggesting a novel treatment strategy involving circCDR1as and the inhibition of autophagy in OSCC cells.