Autophagy and multidrug resistance in cancer

Recent advances in anti-multidrug resistance for nano-drug delivery system

Chemotherapy for tumors occasionally results in drug resistance, which is the major reason for the treatment failure. Higher drug doses could improve the therapeutic effect, but higher toxicity limits the further treatment. For overcoming drug resistance, functional nano-drug delivery system (NDDS) has been explored to sensitize the anticancer drugs and decrease its side effects, which are applied in combating multidrug resistance (MDR) via a variety of mechanisms including bypassing drug efflux, controlling drug release, and disturbing metabolism. This review starts with a brief report on the major MDR causes. Furthermore, we searched the papers from NDDS and introduced the recent advances in sensitizing the chemotherapeutic drugs against MDR tumors. Finally, we concluded that the NDDS was based on several mechanisms, and we looked forward to the future in this field.

KIF23 promotes autophagy-induced imatinib resistance in chronic myeloid leukaemia through activating Wnt/β-catenin pathway

Imatinib, an inhibitor of tyrosine kinase, shows remarkable efficacy in chronic myeloid leukaemia (CML). Autophagy protects tumour cells against chemotherapeutic stimulation and contributes to imatinib resistance in CML. Kinesin family member 23 (KIF23) is involved in cytokinesis and associated with autophagy. The role of KIF23 in autophagy-induced imatinib resistance in CML was investigated. First, to induce drug resistance, CML cells were exposed to increasing concentrations of imatinib. The concentration of imatinib resistance in CML cells was screened through upregulation of 50% inhibitory concentration (IC₅₀ ) values. KIF23 was elevated in imatinib-resistant tissues and cells of CML. Second, knockdown of KIF23 reduced IC₅₀ values of imatinib-resistant CML cells to imatinib. Moreover, silence of KIF23 also suppressed cell proliferation and promoted apoptosis of imatinib-resistant CML cells. Third, immunofluorescence analysis showed that the number of LC3 bright spots in imatinib-resistant CML cells was reduced by silence of KIF23. Knockdown of KIF23 upregulated p62 expression and downregulated the expression ratio of LC3-II to LC3-I in imatinib-resistant CML cells. Last, silence of KIF23 decreased nuclear β-catenin and increased cytoplasmic β-catenin in imatinib-resistant CML cells. Activator of Wnt/β-catenin attenuated KIF23 silence-induced increase of apoptosis and decrease of autophagy in imatinib-resistant CML cells. In conclusion, loss of KIF23 repressed autophagy-induced imatinib resistance in CML cells through inactivation of Wnt/β-catenin pathway.

Biologic Functions of Hydroxychloroquine in Disease: From COVID-19 to Cancer

Chloroquine (CQ) and Hydroxychloroquine (HCQ), initially utilized in the treatment of malaria, have now developed a long list of applications. Despite their clinical relevance, their mechanisms of action are not clearly defined. Major pathways by which these agents are proposed to function include alkalinization of lysosomes and endosomes, downregulation of C-X-C chemokine receptor type 4 (CXCR4) expression, high-mobility group box 1 protein (HMGB1) inhibition, alteration of intracellular calcium, and prevention of thrombus formation. However, there is conflicting data present in the literature. This is likely the result of the complex overlapping pathways between these mechanisms of action that have not previously been highlighted. In fact, prior research has focused on very specific portions of particular pathways without describing these in the context of the extensive CQ/HCQ literature. This review summarizes the detailed data regarding CQ/HCQ's mechanisms of action while also providing insight into the overarching themes. Furthermore, this review provides clinical context to the application of these diverse drugs including their role in malaria, autoimmune disorders, cardiovascular disease, thrombus formation, malignancies, and viral infections.

The RNA-binding protein RBM24 regulates lipid metabolism and SLC7A11 mRNA stability to modulate ferroptosis and inflammatory response

Lipids play a critical role in many cellular processes by serving as structural components of cell membranes or functioning as energy fuel and signaling molecules. The RNA-binding proteins RBM24 and RBM38 share an identical RNA-binding domain and thereby, regulate a group of same targets, such as p21. However, it is not certain whether RBM24 and RBM38 participates in lipid homeostasis. Here, lipidomic analysis showed that a deficiency in RBM24 or RBM38 leads to altered lipid metabolism, with more profound alteration by loss of RBM24 in MCF7 cells. We also showed that mice deficient in RBM24 were prone to chronic inflammation and liver steatosis, but not spontaneous tumors. These data let us speculate whether RBM24 regulates ferroptosis, a programmed cell death that links inflammation and liver steatosis via lipid peroxidation. Indeed, we found that over-expression of RBM24 protected, whereas knockout of RBM24 sensitized, cells to Erastin-induced ferroptosis by modulating the mRNA stability of SLC7A11, a ferroptosis inhibitor. Moreover, we showed that knockdown of SLC7A11 reversed the effect of RBM24 on ferroptosis. Together, our study revealed that RBM24 regulates lipid metabolism and SLC7A11 mRNA stability to modulate ferroptosis and inflammatory response.

Targeting of non-apoptotic cancer cell death mechanisms by quercetin: Implications in cancer therapy

The ultimate goal of cancer treatment is to kill cancer cells, based on the use of various therapeutic agents, such as chemotherapy, radiotherapy, or targeted therapy drugs. Most drugs exert their therapeutic effects on cancer by targeting apoptosis. However, alterations in apoptosis-related molecules and thus assisting cells to evade death, eventually lead to tumor cell resistance to therapeutic drugs. The increased incidence of non-apoptotic cell death modes such as induced autophagy, mitotic catastrophe, senescence, and necrosis is beneficial to overcoming multidrug resistance mediated by apoptosis resistance in tumor cells. Therefore, investigating the function and mechanism of drug-induced non-apoptotic cell death modes has positive implications for the development of new anti-cancer drugs and therapeutic strategies. Phytochemicals show strong potential as an alternative or complementary medicine for alleviating various types of cancer. Quercetin is a flavonoid compound widely found in the daily diet that demonstrates a significant role in inhibiting numerous human cancers. In addition to direct pro-tumor cell apoptosis, both in vivo and in vitro experiments have shown that quercetin exerts anti-tumor properties by triggering diverse non-apoptotic cell death modes. This review summarized the current status of research on the molecular mechanisms and targets through which quercetin-mediated non-apoptotic mode of cancer cell death, including autophagic cell death, senescence, mitotic catastrophe, ferroptosis, necroptosis, etc.

New Iron Metabolic Pathways and Chelation Targeting Strategies Affecting the Treatment of All Types and Stages of Cancer

There is new and increasing evidence from in vitro, in vivo and clinical studies implicating the pivotal role of iron and associated metabolic pathways in the initiation, progression and development of cancer and in cancer metastasis. New metabolic and toxicity mechanisms and pathways, as well as genomic, transcription and other factors, have been linked to cancer and many are related to iron. Accordingly, a number of new targets for iron chelators have been identified and characterized in new anticancer strategies, in addition to the classical restriction of/reduction in iron supply, the inhibition of transferrin iron delivery, the inhibition of ribonucleotide reductase in DNA synthesis and high antioxidant potential. The new targets include the removal of excess iron from iron-laden macrophages, which affects anticancer activity; the modulation of ferroptosis; ferritin iron removal and the control of hyperferritinemia; the inhibition of hypoxia related to the role of hypoxia-inducible factor (HIF); modulation of the function of new molecular species such as STEAP4 metalloreductase and the metastasis suppressor N-MYC downstream-regulated gene-1 (NDRG1); modulation of the metabolic pathways of oxidative stress damage affecting mitochondrial function, etc. Many of these new, but also previously known associated iron metabolic pathways appear to affect all stages of cancer, as well as metastasis and drug resistance. Iron-chelating drugs and especially deferiprone (L1), has been shown in many recent studies to fulfill the role of multi-target anticancer drug linked to the above and also other iron targets, and has been proposed for phase II trials in cancer patients. In contrast, lipophilic chelators and their iron complexes are proposed for the induction of ferroptosis in some refractory or recurring tumors in drug resistance and metastasis where effective treatments are absent. There is a need to readdress cancer therapy and include therapeutic strategies targeting multifactorial processes, including the application of multi-targeting drugs involving iron chelators and iron-chelator complexes. New therapeutic protocols including drug combinations with L1 and other chelating drugs could increase anticancer activity, decrease drug resistance and metastasis, improve treatments, reduce toxicity and increase overall survival in cancer patients.

d-Borneol enhances cisplatin sensitivity via autophagy dependent EMT signaling and NCOA4-mediated ferritinophagy

BACKGROUND

d-Borneol has been widely used as a drug absorption enhancer, but there are few studies on the anti-resistance ability of d-borneol combined with cisplatin in cisplatin-resistant non-small cell lung cancer cells. Ferroptosis, autophagy and epithelial-mesenchymal transition (EMT) have been reported to be associated with drug resistance.

PURPOSE

To investigate the molecular mechanisms and sensitizing effects of d-borneol combined with cisplatin to against drug cisplatin resistance from the perspective of ferroptosis, autophagy and EMT resistance.

METHODS

H460/CDDP xenograft tumor model was established to verify the antitumor activity and safety in vivo. RNA sequencing was used to predict target molecules and signaling pathways. Reactive oxygen species (ROS) were used as marker of ferroptosis, and its level was determined by a dichlorodihydrofluorescein diacetate fluorescent probe and flow cytometry. Levels of glutathione (GSH), malondialdehyde (MDA), and antioxidants such as superoxide dismutase (SOD) and thioredoxin (Trx) involved in the balance of oxidative stress were measured by an assay kit or enzyme-linked immunosorbent assay. Western blotting and real-time polymerase chain reaction were used to assess the regulatory mechanism of EMT markers, autophagy, and ferroptosis signaling pathways.

RESULTS

d-Borneol in combination with cisplatin reduced tumor volume and weight, enhanced tumor-inhibiting effects, and alleviated cisplatin-induced damage to the liver and kidney in vivo. RNA-sequencing showed that differentially expressed genes were enriched in ferroptosis. d-Borneol in combination with cisplatin promoted ROS accumulation, increased the content of MDA levels, and decreased GSH, SOD, Trx, and heme oxygenase-1 expression to induce oxidative damage. d-Borneol combination with cisplatin induced ferroptosis by promoting nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy and regulating intracellular iron ion transport via upregulating PRNP and downregulating PCBP2. In addition, d-borneol combined with cisplatin promoted autophagy by upregulating expression of LC3II/ATG5/Beclin-1 and inhibited the EMT by increasing the expression of epithelial marker E-cadherin and decreasing mesenchymal markers (N-cadherin and vimentin) and transcription factors (Snail and ZEB1).

CONCLUSION

For the first time, our study implies that d-borneol enhanced cisplatin sensitivity by inducing ferroptosis, promoting autophagy and inhibiting EMT progression, thereby enhancing antitumor activity. It suggests that d-borneol could be developed as a novel chemosensitizers.

Heparin and Heparin-Based Drug Delivery Systems: Pleiotropic Molecular Effects at Multiple Drug Resistance of Osteosarcoma and Immune Cells

One of the main problems of modern health care is the growing number of oncological diseases both in the elderly and young population. Inadequately effective chemotherapy, which remains the main method of cancer control, is largely associated with the emergence of multidrug resistance in tumor cells. The search for new solutions to overcome the resistance of malignant cells to pharmacological agents is being actively pursued. Another serious problem is immunosuppression caused both by the tumor cells themselves and by antitumor drugs. Of great interest in this context is heparin, a biomolecule belonging to the class of glycosaminoglycans and possessing a broad spectrum of biological activity, including immunomodulatory and antitumor properties. In the context of the rapid development of the new field of “osteoimmunology,” which focuses on the collaboration of bone and immune cells, heparin and delivery systems based on it may be of intriguing importance for the oncotherapy of malignant bone tumors. Osteosarcoma is a rare but highly aggressive, chemoresistant malignant tumor that affects young adults and is characterized by constant recurrence and metastasis. This review describes the direct and immune-mediated regulatory effects of heparin and drug delivery systems based on it on the molecular mechanisms of (multiple) drug resistance in (onco) pathological conditions of bone tissue, especially osteosarcoma.

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.

FOXM1-mediated NUF2 expression confers temozolomide resistance to human glioma cells by regulating autophagy via the PI3K/AKT/mTOR signaling pathway

Glioma is the most common malignant tumor in the central nervous system and has a high mortality rate. Temozolomide (TMZ) is a widely used chemotherapeutic drug for glioma. NDC80 kinetochore complex (NUF2) is suggested to play a regulatory role in different cancers, but its specific function and mechanism in glioblastoma TMZ resistance remain unknown. NUF2, assessed by reverse transcription quantitative polymerase chain reaction (RT-qPCR), was highly expressed in glioma cell lines. TMZ was used to treat cells to establish a TMZ-resistant cell line. The potential functions of NUF2 in glioma were assessed using cell counting kit-8 (CCK-8) assays, colony formation assays, 5-Ethynyl-2'-deoxyuridine (EdU) assays, flow cytometry, Western blotting, and a tumor xenograft model. The results showed that NUF2 knockdown attenuated malignant phenotypes of TMZ-resistant cells and prevented tumor growth. Mechanistically, as luciferase reporter assays and chromatin immunoprecipitation (ChIP) as showed, Fox transcription factor M1 (FOXM1) had binding sites on the NUF2 promoter. Rescue assays demonstrated that FOXM1 upregulation counteracted the inhibitory effects of NUF2 depletion on the malignancies of TMZ-resistant cells. This study demonstrates that FOXM1-activated NUF2 promotes TMZ to human glioma cells by regulating proliferation, apoptosis, and autophagy.

Establishment and validation of individualized clinical prognostic markers for LUAD patients based on autophagy-related genes

There is considerable heterogeneity in the genomic drivers of lung adenocarcinoma, which has a dismal prognosis. Bioinformatics analysis was performed on lung adenocarcinoma (LUAD) datasets to establish a multi-autophagy gene model to predict patient prognosis. LUAD data were downloaded from The Cancer Genome Atlas (TCGA) database as a training set to construct a LUAD prognostic model. According to the risk score, a Kaplan-Meier cumulative curve was plotted to evaluate the prognostic value. Furthermore, a nomogram was established to predict the three-year and five-year survival of patients with LUAD based on their prognostic characteristics. Two genes (ITGB1 and EIF2AK3) were identified in the autophagy-related prognostic model, and the multivariate Cox proportional risk model showed that risk score was an independent predictor of prognosis in LUAD patients (HR=3.3, 95%CI= 2.3 to 4.6, P< 0.0001). The Kaplan-Meier cumulative curve showed that low-risk patients had significantly better overall (P<0.0001). The validation dataset GSE68465 further confirmed the nomogram’s robust ability to assess the prognosis of LUAD patients. A prognosis model of autophagy-related genes based on a LUAD dataset was constructed and exhibited diagnostic value in the prognosis of LUAD patients. Moreover, real-time qPCR confirmed the expression patterns of EIF2AK3 and ITGB1 in LUAD cell lines. Two key autophagy-related genes have been suggested as prognostic markers for lung adenocarcinoma.

Paclitaxel-loaded ginsenoside Rg3 liposomes for drug-resistant cancer therapy by dual targeting of the tumor microenvironment and cancer cells

INTRODUCTION

Inherent or acquired resistance to paclitaxel (PTX) is a pivotal challenge for chemotherapy treatment of multidrug-resistant (MDR) breast cancer. Although various targeted drug-delivery systems, including nanoparticles and liposomes, are effective for MDR cancer treatment, their efficacy is restricted by immunosuppressive tumor microenvironment (TME).

METHODS

Ginsenosides Rg3 was used to formulate unique Rg3-based liposomes loaded with PTX to establish Rg3-PTX-LPs, which were prepared by the thin-film hydration method. The stability of the Rg3-PTX-LPs was evaluated by particle size analysis through dynamic light scattering. The active targeting effect of Rg3-based liposomes was examined in an MCF-7/T xenograft model by an in a vivo imaging system. To evaluate the antitumor activity and mechanism of Rg3-PTX-LP, MTT, apoptosis assays, TAM regulation, and TME remodeling were performed in MCF-7/T cells in vitro and in vivo.

RESULTS

Rg3-PTX-LPs could specifically distribute to MCF7/T cancer cells and TME simultaneously, mainly through the recognition of GLUT-1. The drug resistance reversing capability and in vivo antitumor effect of Rg3-PTX-LPs were significantly improved compared with conventional cholesterol liposomes. The TME remodeling mechanisms of Rg3-PTX-LPs included inhibiting IL-6/STAT3/p-STAT3 pathway activation to repolarize protumor M2 macrophages to antitumor M1 phenotype, suppressing myeloid-derived suppressor cells (MDSCs), decreasing tumor-associated fibroblasts (TAFs) and collagen fibers in TME, and promoting apoptosis of tumor cells. Hence, through the dual effects of targeting tumor cells and TME remodeling, Rg3-PTX-LPs achieved a high tumor inhibition rate of 90.3%.

CONCLUSION

Our multifunctional Rg3-based liposome developed in the present study offered a promising strategy for rescuing the drug resistance tumor treatment.

PSMG2-controlled proteasome-autophagy balance mediates the tolerance for MEK-targeted therapy in triple-negative breast cancer

Although the MAPK pathway is aberrantly activated in triple-negative breast cancers (TNBCs), the clinical outcome of MEK-targeted therapy is still poor. Through a genome-wide CRISPR-Cas9 library screening, we find that inhibition of PSMG2 sensitizes TNBC cells BT549 and MB468 to the MEK inhibitor AZD6244. Mechanistically, PSMG2 knockdown impairs proteasome function, which in turn activates autophagy-mediated PDPK1 degradation. The PDPK1 degradation significantly enhances AZD6244-induced tumor cell growth inhibition by interrupting the negative feedback signals toward the AKT pathway. Consistently, co-targeting proteasomes and MEK with inhibitors synergistically suppresses tumor cell growth. The autophagy inhibitor chloroquine partially relieves the PDPK1 degradation and reverses the growth inhibition induced by combinatorial inhibition of MEK and proteasome. The combination regimen with the proteasome inhibitor MG132 plus AZD6244 synergistically inhibits tumor growth in a 4T1 xenograft mouse model. In summary, our study not only unravels the mechanism of MEK inhibitor resistance but also provides a combinatorial therapeutic strategy for TNBC in clinics.

Natural products exert anti-tumor effects by regulating exosomal ncRNA

Currently, more than 60% of the approved anti-cancer drugs come from or are related to natural products. Natural products and exosomal non-coding RNAs (ncRNAs) exert anti-cancer effects through various regulatory mechanisms, which are of great research significance. Exosomes are a form of intercellular communication and contain ncRNAs that can act as intercellular signaling molecules involved in the metabolism of tumor cells. This review exemplifies some examples of natural products whose active ingredients can play a role in cancer prevention and treatment by regulating exosomal ncRNAs, with the aim of illustrating the mechanism of action of exosomal ncRNAs in cancer prevention and treatment. Meanwhile, the application of exosomes as natural drug delivery systems and predictive disease biomarkers in cancer prevention and treatment is introduced, providing research ideas for the development of novel anti-tumor drugs.

Protein tyrosine kinase inhibitor resistance in malignant tumors: molecular mechanisms and future perspective

Protein tyrosine kinases (PTKs) are a class of proteins with tyrosine kinase activity that phosphorylate tyrosine residues of critical molecules in signaling pathways. Their basal function is essential for maintaining normal cell growth and differentiation. However, aberrant activation of PTKs caused by various factors can deviate cell function from the expected trajectory to an abnormal growth state, leading to carcinogenesis. Inhibiting the aberrant PTK function could inhibit tumor growth. Therefore, tyrosine kinase inhibitors (TKIs), target-specific inhibitors of PTKs, have been used in treating malignant tumors and play a significant role in targeted therapy of cancer. Currently, drug resistance is the main reason for limiting TKIs efficacy of cancer. The increasing studies indicated that tumor microenvironment, cell death resistance, tumor metabolism, epigenetic modification and abnormal metabolism of TKIs were deeply involved in tumor development and TKI resistance, besides the abnormal activation of PTK-related signaling pathways involved in gene mutations. Accordingly, it is of great significance to study the underlying mechanisms of TKIs resistance and find solutions to reverse TKIs resistance for improving TKIs efficacy of cancer. Herein, we reviewed the drug resistance mechanisms of TKIs and the potential approaches to overcome TKI resistance, aiming to provide a theoretical basis for improving the efficacy of TKIs.

Effects of polymer carriers on the occurrence and development of autophagy in drug delivery

Autophagy is an evolutionarily conserved catabolic process that can degrade cytoplasmic materials and recycle energy to maintain metabolite homeostasis in cells. Autophagy is closely related to various physiological or pathological processes. Macromolecular materials are widely used in drug delivery systems and disease treatments due to their intrinsic effects, such as altered pharmacokinetics and biodistribution. Interaction of autophagic flux or the signal pathway with macromolecules may cause autophagy inhibition or autophagy cell death. This review covers autophagy regulation pathways and macromolecular materials (including functional micelles, biodegradable and pH-sensitive polymers, biomacromolecules, dendrimers, coordination polymers, and hybrid nanoparticles) mediated autophagy modulation.

Embelin and Its Derivatives: Design, Synthesis, and Potential Delivery Systems for Cancer Therapy

Embelin is a naturally occurring benzoquinone that inhibits the growth of cancer cells, making it a potent anticancer drug. However, the low water solubility of embelin restricts its clinical applicability. This review provides a concise summary and in-depth analysis of the published literature on the design and synthesis of embelin derivatives possessing increased aqueous solubility and superior therapeutic efficacy. In addition, the potential of drug delivery systems to improve the anticancer capabilities of embelin and its derivatives is discussed.

Potential Therapeutic Agents against Paclitaxel—And Sorafenib-Resistant Papillary Thyroid Carcinoma

Thyroid carcinoma, a disease in which malignant cells form in the thyroid tissue, is the most common endocrine carcinoma, with papillary thyroid carcinoma (PTC) accounting for nearly 80% of total thyroid carcinoma cases. However, the management of metastatic or recurrent therapy-refractory PTC is challenging and requires complex carcinoma therapy. In this study, we proposed a new clinical approach for the treatment of therapy-refractory PTC. We identified sarco/endoplasmic reticulum calcium ATPase (SERCA) as an essential factor for the survival of PTC cells refractory to the treatment with paclitaxel or sorafenib. We validated its use as a potential target for developing drugs against resistant PTC, by using patient-derived paclitaxel- or sorafenib-resistant PTC cells. We further discovered novel SERCA inhibitors, candidates 7 and 13, using the evolutionary chemical binding similarity method. These novel SERCA inhibitors determined a substantial reduction of tumors in a patient-derived xenograft tumor model developed using paclitaxel- or sorafenib-resistant PTC cells. These results could provide a basis for clinically meaningful progress in the treatment of refractory PTC by identifying a novel therapeutic strategy: using a combination therapy between sorafenib or paclitaxel and specific SERCA inhibitors for effectively and selectively targeting extremely malignant cells such as antineoplastic-resistant and carcinoma stem-like cells.

The lncRNA CRNDE is regulated by E2F6 and sensitizes gastric cancer cells to chemotherapy by inhibiting autophagy

Chemotherapy is an important treatment for gastric cancer (GC), but the primary and secondary drug resistance of tumours to chemotherapy seriously affects its curative effect. In recent years, the relationship between long noncoding RNAs (lncRNAs) and malignant tumours has received increasing attention. Based on accumulating evidence, lncRNAs are involved in the chemoresistance of GC, but the underlying mechanisms remain unclear. In this study, we identified the lncRNA colorectal neoplasia differentially expressed (CRNDE) as an important regulator of autophagy-associated chemoresistance in GC. Mechanistically, overexpression of CRNDE inhibits autophagy and induces apoptosis, thereby sensitizing GC cells to chemotherapy drugs. Moreover, E2F6, a classical transcriptional inhibitor, is confirmed to be upregulated in GC and represses the expression of CRNDE. The E2F6-CRNDE axis is clinically related to chemoresistant GC and poor outcomes in patients with advanced GC. Our findings suggest that the E2F6-CRNDE axis is a viable therapeutic target to protect against chemoresistance in GC.

Rutaecarpine prevents the malignant biological properties of breast cancer cells by the miR-149-3p/S100A4 axis

Background

Breast cancer (BC) is a frequent malignancy that endangers women's health, and its fatality rate ranks 1st among female malignancies. Research has shown that rutaecarpine (RUT), which is a Chinese herbal medicine, blocks the proliferation of cancer cells by a variety of molecular mechanisms. However, the possible effects and mechanism of RUT in the autophagy and angiogenesis of BC cells has not been clearly articulated.

Methods

MiR-149-3p and S100A4 expression levels were assessed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and the optimal concentration and time of RUT was confirmed by Cell Counting Kit-8 (CCK-8) assays of the BC cells. After treatment, changes in cell proliferation and the cell cycle were evaluated by CCK-8 assays, clone formation assays, and flow cytometry, and the levels of apoptosis, autophagy, and angiogenesis-related proteins were identified by Western blot. The targeted regulation of miR-149-3p on S100A4 was also examined by luciferase reporter assays.

Results

We found that RUT inhibited cell growth and upregulated miR-149-3p in MDA-MB-231 cells. In relation to the biological function activity, RUT attenuated proliferation and angiogenesis, and induced cell-cycle arrest and autophagy by miR-149-3p in the MDA-MB-231 cells. Additionally, miR-149-3p downregulated S100A4 by targeting binding to S100A4, and S100A4 was required for miR-149-3p to play a role in BC progression. We also discovered that an autophagy agonist (rapamycin) or an angiogenesis inhibitor (TNP-470) changed BC progression mediated by the RUT/miR-149-3p/S100A4 axis.

Conclusions

RUT blocks the malignant behaviors of BC cells through the miR-149-3p/S100A4 axis and thus alters autophagy and angiogenesis. Thus, the RUT-mediated miR-149-3p/S100A4 axis might be an underlying therapeutic agent and target for BC.

Soybean Isoflavones Activating Autophagy and Improving the Chemosensitivity of Carboplatin to Ovarian Cancer Cells

Objection: To discuss soybean isoflavones activating autophagy and improving the chemosensitivity of carboplatin to ovarian cancer cells. Materials and Methods: Using SKOV3 and A2780 cell lines as research object, dividing into Normal, Carb (treated with 50 μmol/L carboplatin) and Carb+Soy (treated with 50 μmol/L carboplatin and 80 μmol/L soybean isoflavone). Evaluating cell proliferation by EdU and MTT assay; measuring cell apoptosis rate by flow cytometry; observation cells’ autophagy by transmission electron microscope (TEM); LC 3B protein expression were evaluated by cellular immunofluorescence and using WB assay to evaluate autophagy relative proteins expression. Results: Compared with Normal group, the cell proliferation were significantly depressed with cell apoptosis rates significantly increasing (P < 0.01, respectively); and autophagy enhancing; with LC 3B, LC 3II/LC 3I ratio and Beclin 1 significantly up-regulation and P62 protein significantly down-regulation (P < 0.01, respectively) in Carb and Carb+Soy groups. And there were significantly differences between Carb and Carb+Soy groups in EdU cell number, cell proliferation, apoptosis rate, autophagy, LC 3B, LC 3II/LC 3I ratio, Beclin 1 and P62 protein expression. Conclusion: Soy activating autophagy and improving the chemosensitivity of carboplatin to ovarian cancer cells.

Autophagy in gastrointestinal cancers

Gastrointestinal cancers are a group of cancers occurred in gastrointestinal tissues with high morbidity and mortality rate. Although numerous studies were conducted on the investigation of gastrointestinal cancers, the real mechanisms haven’t been discovered, and no effective methods of prevention and treatment of gastrointestinal cancers have been developed. Autophagy, a vital catabolic process in organisms, have been proven to participate in various mechanisms and signaling pathways, thus producing a regulatory effect on various diseases. The role of autophagy in gastrointestinal cancers remains unclear due to its high complexity. In this review, firstly, the biological features of autophagy will be introduced. Secondly, the role of autophagy in three popular gastrointestinal cancers, namely esophageal cancer, gastric cancer, and colorectal cancer will be described and discussed by reviewing the related literature. We aimed to bring novel insights in exploring the real mechanisms for gastrointestinal cancers and developing effective and efficient therapeutic methods to treat gastrointestinal cancers.

Oncolytic Impediment/Promotion Balance Disruption by Sonosensitizer-Free Nanoplatforms Unfreezes Autophagy-Induced Resistance to Sonocatalytic Therapy

Autophagy as a double-edged sword features an oncolytic impediment/promotion balance, which manipulates tumor progression. From this perspective, a sonosensitizer-free targeting oncolytic nanoplatform (SFTON) consisting of chloroquine (CQ) and porphyrin-structured metal centers (PMCS) was engineered to break this balance for enhancing antitumor activity. Porphyrin structure retention in a ZIF-8-derived hydrophobic carbon skeleton retained high stability and high sonocatalytic activity, and the hydrophobic carbon skeleton capable of adsorbing air provided cavitation nuclei for further elevating sonocatalytic activity. More significantly, the encapsulated CQ as the autophagy inhibitor reprogrammed autophagy, terminated the autophagy-induced self-protection or self-detoxification, and unfroze the resistances to reactive oxygen species (ROS) therapy associated with ROS accumulation and ROS activity. Systematic experiments reveal the action principles and validate that the induced apoptosis and blockaded autophagosome escalation into the autolysosome were two activated pathways to magnify the antitumor sonocatalytic therapy. Contributed by these actions, the SFTON-unlocked oncolytic impediment/promotion balance disruption strategy acquired considerable antitumor outcomes in vivo and in vitro against liver tumor progression, especially after combining with AS1411-mediated active targeting. This impediment/promotion balance disruption enabled by the SFTON can serve as a general method to elevate ROS-based antitumor activity.

Lidocaine inhibits the proliferation and migration of endometrial cancer cells, and promotes apoptosis by inducing autophagy

As a gynecological malignancy, endometrial cancer (EC) has a high incidence and mortality rate in women. The aim of the present study was to investigate the mechanism of EC and to identify novel effective treatment methods for this disease. The viability and proliferation of the RL95-2 human endometrial cancer cell line were assessed using Cell Counting Kit-8 assays. Colony formation, wound healing, Transwell, TUNEL and immunofluorescence assays were used to assess the effects of 5, 10 and 15 mM lidocaine on the colony formation, migration, invasiveness, apoptosis and Beclin 1 protein expression of RL95-2 cells, respectively. Furthermore, western blotting was used to analyze the protein expression levels of apoptosis- and autophagy-related proteins. The results demonstrated that lidocaine inhibited the viability, proliferation and migration of EC cells, and promoted apoptosis. Furthermore, lidocaine was demonstrated to induce autophagy and Beclin 1 protein expression in EC cells. In conclusion, lidocaine inhibited the proliferation and migration of EC cells, and promoted apoptosis via autophagy induction, which indicated that lidocaine may be a potential therapeutic drug for the treatment of EC.

Significant position of C-myc in colorectal cancer: a promising therapeutic target

Colorectal cancer (CRC) is a malignant tumor initiating from the mucosa of the colorectum. According to the 2020 statistics from the World Health Organization, there are 10.0% CRC cases among all 19.3 million new cancers, followed by lung and breast cancer, and 9.4% CRC cases among all 9.9 million cancer deaths, ranking second. The population of CRC patients in China is large, and its incidence and mortality continue to increase each year. Despite the continuous development of surgical methods, chemotherapy, radiotherapy, targeted therapy and immunotherapy, the overall survival of CRC patients remains low. Past research has suggested that c-myc plays a pivotal role in the development of CRC. A higher expression level of c-Myc is a negative prognostic marker in CRC. However, there are few drugs targeting c-myc directly. Therefore, we focused on discovering the mechanism of c-myc in CRC to provide a reference for a better therapy choice for patients.

Identification of an autophagy-related 12-lncRNA signature and evaluation of NFYC-AS1 as a pro-cancer factor in lung adenocarcinoma

Objective: To develop an autophagy-related lncRNA-based risk signature and corresponding nomogram to predict overall survival (OS) for LUAD patients and investigate the possible meaning of screened factors.

Methods: Differentially expressed lncRNAs and autophagy genes were screened between normal and LUAD tumor samples from the TCGA LUAD dataset. Univariate and multivariate Cox regression analyses were performed to construct the lncRNA-based risk signature and nomogram incorporating clinical information. Then, the accuracy and sensitivity were confirmed by the AUC of ROC curves in both training and validation cohorts. qPCR, immunoblot, shRNA, and ectopic expression were used to verify the positive regulation of NFYC-AS1 on BIRC6. CCK-8, immunofluorescence, and flow cytometry were used to confirm the influence of NFYC-AS1 on cell proliferation, autophagy, and apoptosis via BIRC6.

Results: A 12-lncRNA risk signature and a nomogram combining related clinical information were constructed. Furthermore, the abnormal increase of NFYC-AS1 may promote LUAD progression through the autophagy-related gene BIRC6.

Conclusion: 12-lncRNA signature may function as a predictive marker for LUAD patients, and NFYC-AS1 along with BIRC6 may function as carcinogenic factors in a combinatorial manner.

A Systematic Review of Apoptosis in Correlation With Cancer: Should Apoptosis Be the Ultimate Target for Cancer Treatment?

Targeting apoptosis in cancer therapy has become increasingly popular, and there has been an increasing debate on whether apoptosis should be one of the main targets of therapy in cancer management. This study demonstrates the definition of apoptosis, the signaling pathways, and the pathogenesis behind it. We also show the correlation between apoptosis and cancer and how cancer can evade apoptosis to develop resistance to therapy. In addition, we illustrate the efficacy of adding pro-apoptotic therapy to conventional radio-chemotherapy cancer treatment. A systematic review was conducted using PubMed, PubMed Central (PMC), and ResearchGate, including papers written in English, focusing on adult and geriatric populations, in literature reviews, systematic reviews, and randomized controlled trials published in the last 25 years with relevance to the question. Based on the findings of this review, we conclude that apoptosis is a very sophisticated programmed cellular death with many signaling pathways. Its evasion should be considered one of the hallmarks of cancer and is responsible for multiple drug resistance (MDR) to cancer therapy. Targeting apoptosis seems promising, especially if combined with radio-chemotherapy.

Emerging role of lncRNAs in drug resistance mechanisms in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) originates in the squamous cell lining the mucosal surfaces of the head and neck region, including the oral cavity, nasopharynx, tonsils, oropharynx, larynx, and hypopharynx. The heterogeneity, anatomical, and functional characteristics of the patient make the HNSCC a complex and difficult-to-treat disease, leading to a poor survival rate and a decreased quality of life due to the loss of important physiologic functions and aggressive surgical injury. Alteration of driver-oncogenic and tumor-suppressing lncRNAs has recently been recently in HNSCC to obtain possible biomarkers for diagnostic, prognostic, and therapeutic approaches. This review provides current knowledge about the implication of lncRNAs in drug resistance mechanisms in HNSCC. Chemotherapy resistance is a major therapeutic challenge in HNSCC in which lncRNAs are implicated. Lately, it has been shown that lncRNAs involved in autophagy induced by chemotherapy and epithelial–mesenchymal transition (EMT) can act as mechanisms of resistance to anticancer drugs. Conversely, lncRNAs involved in mesenchymal–epithelial transition (MET) are related to chemosensitivity and inhibition of invasiveness of drug-resistant cells. In this regard, long non-coding RNAs (lncRNAs) play a pivotal role in both processes and are important for cancer detection, progression, diagnosis, therapy response, and prognostic values. As the involvement of more lncRNAs is elucidated in chemoresistance mechanisms, an improvement in diagnostic and prognostic tools could promote an advance in targeted and specific therapies in precision oncology.

Brucea javanica Oil Emulsion Promotes Autophagy in Ovarian Cancer Cells Through the miR-8485/LAMTOR3/mTOR/ATG13 Signaling Axis

Background: Ovarian cancer is a common malignant tumor of the female reproductive tract, with the highest mortality rate. At present, no effective approaches to improve the survival rate exist. B. javanica Oil Emulsion (BJOE), an extract from B. javanica (L.) Merr. [Simaroubaceae], exhibits antitumor effects and can increase the sensitivity of radiotherapy and chemotherapy in many types of cancers. MiR-8485, a discovered miRNA, has been shown to be involved in the occurrence and development of tumors. The purpose of this study was to investigate the effect of BJOE on the regulation of mammalian rapamycin target protein (mTOR) autophagy signal pathway and related autophagy factors on ovarian cancer cells through miR-8485.

Methods: The main chemical constituents of BJOE were determined by UHPLC-MS/MS. Detection of miR-8485 expression in ovarian cancer cells treated with BJOE by quantitative reverse transcription polymerase chain reaction (qRT-PCR). CCK8 experiment and flow cytometry were used to observe the effects of BJOE and overexpression of miR-8485 on cell proliferation and apoptosis. Then, monodansylcadaverine (MDC) fluorescence staining was used to observe the changes of autophagy vesicles before and after the effect of BJOE and overexpressed miR-8485 on cancer cells. Next, the binding sites between miR8485 and mammalian rapamycin target protein activator 3 (LAMTOR3) were detected by double luciferase reporter assay. Furthermore, qRT-PCR and Western blot experiments were used to explore the changes of autophagy-related factors LAMTOR3, mTOR and autophagy-related 13 (ATG13), and microtubule associated protein 1 light chain 3 beta (LC3-Ⅱ) after BJOE and overexpression of miR-8485, in addition to autophagy inhibitor (3-MA) for rescue experiment verification.

Results: The qRT-PCR results showed that the expression of miR-8485 increased after BJOE treatment in the SKOV3 cell. The CCK8 assay and flow cytometry analysis revealed that both BJOE and miR-8485 overexpression inhibited the proliferation and promoted the apoptosis of the SKOV3 cell. MDC fluorescence staining showed that BJOE and miR-8485 overexpression led to a significant increase in autophagy vesicles in the SKOV3 cell. Double luciferase reporter assay confirmed the existence of binding sites between miR8485 and LAMTOR3. The results of qRT-PCR and Western blot showed that BJOE and overexpressed miR-8485 downregulated the expression of LAMTOR3 and mTOR and up-regulated the expression of ATG13 and LC3-Ⅱ.

Conclusion: 1) MiR-8485 may be the key factor of BJOE in promoting autophagy and apoptosis and inhibiting cell proliferation of ovarian cancer cells; 2) BJOE may play an antitumor role by regulating LAMTOR3/mTOR/ATG13 signaling axis through miR-8485 to promote autophagy in ovarian cancer cells.

Nodosin Exerts an Anti-Colorectal Cancer Effect by Inhibiting Proliferation and Triggering Complex Cell Death in Vitro and in Vivo

Colorectal cancer (CRC) is one of the most common digestive system cancer in the world. Its incidence and mortality are increasing annually. Presently, CRC lacks long-term effective treatment methods and drugs. Therefore, finding new treatment methods and drugs is of great significance for CRC treatment. Compounds derived from natural plants have been widely used in tumor research and treatment because of their good antitumor activity these years. This study found that nodosin, a diterpenoid extracted from the medicinal plant Rabdosia serra (Maxim.) Hara, inhibited the growth of CRC cells SW480, HT-29 and LoVo in a dose- and time-dependent manner, with inhibitory concentrations (IC50) of 7.4, 7.7, and 6.6 μM respectively. We selected highly metastatic and poorly differentiated SW480 cells for further studies. We found that nodosin could inhibit cell proliferation by inhibiting DNA synthesis and induce cell death by inducing oxidative stress, apoptosis and autophagy in cells. Through in vitro assays combined with transcriptomic analysis, it was found that nodosin could downregulate tribbles pseudokinase 3 and upregulate oxidative stress-induced growth inhibitor 1 to induce oxidative stress in cells; nodosin-induced reactive oxygen species were able to upregulate the expression of heme oxygenase 1 to induce apoptosis and the expression of cathepsin L. and light chain-3 to induce autophagy. In vivo, we found that nodosin inhibited tumor growth and induced cells to undergo apoptosis and autophagy without significant toxic effects. In conclusion, our findings suggest that nodosin exerts anti-CRC effects mainly through its ability to induce apoptosis and autophagy in vitro and in vivo. Therefore, our study contributes to the development of nodosin-based potential CRC therapeutic drugs.

The Role of Pyroptosis and Autophagy in Ischemia Reperfusion Injury

Pyroptosis is a process of programmed cell death mediated by gasdermin (GSDM) found in recent years. In the process of pyroptosis, caspase-1 or caspase-11/4/5 is activated, which cleaves gasdermin D and separates its N-terminal pore-forming domain (PFD). The oligomers of PFD bind to the cell membrane and form macropores on the membrane, resulting in cell swelling and membrane rupture. Increasing evidence indicates that pyroptosis is involved in many diseases, including ischemia reperfusion injury. Autophagy is a highly conserved catabolic process in eukaryotic cells. It plays an important role in the survival and maintenance of cells by degrading organelles, proteins, and macromolecules in the cytoplasm and recycling degradation products. Increasing evidence shows that dysfunctional autophagy participates in many diseases. Recently, autophagy and pyroptosis have been reported to play a vital role in the process of ischemia/reperfusion injury, but the related mechanisms are not completely clear. Therefore, this article reviews the role of autophagy and pyroptosis in ischemia–reperfusion injury and analyzes the related mechanisms to provide a basis for future research.

Mutual regulation between N6-methyladenosine (m6A) modification and circular RNAs in cancer: impacts on therapeutic resistance

The resistance of tumor cells to therapy severely impairs the efficacy of treatment, leading to recurrence and metastasis of various cancers. Clarifying the underlying mechanisms of therapeutic resistance may provide new strategies for overcoming cancer resistance. N6-methyladenosine (m6A) is the most prevalent RNA modification in eukaryotes, and is involved in the regulation of RNA splicing, translation, transport, degradation, stability and processing, thus affecting several physiological processes and cancer progression. As a novel type of multifunctional non-coding RNAs (ncRNAs), circular RNAs (circRNAs) have been demonstrated to play vital roles in anticancer therapy. Currently, accumulating studies have revealed the mutual regulation of m6A modification and circRNAs, and their interaction can further influence the sensitivity of cancer treatment. In this review, we mainly summarized the recent advances of m6A modification and circRNAs in the modulation of cancer therapeutic resistance, as well as their interplay and potential mechanisms, providing promising insights and future directions in reversal of therapeutic resistance in cancer.

Chemopreventive Potential of Dietary Nanonutraceuticals for Prostate Cancer: An Extensive Review

There are more than two hundred fifty different types of cancers, that are diagnosed around the world. Prostate cancer is one of the suspicious type of cancer spreading very fast around the world, it is reported that in 2018, 29430 patients died of prostate cancer in the United State of America (USA), and hence it is expected that one out of nine men diagnosed with this severe disease during their lives. Medical science has identified cancer at several stages and indicated genes mutations involved in the cancer cell progressions. Genetic implications have been studied extensively in cancer cell growth. So most efficacious drug for prostate cancer is highly required just like other severe diseases for men. So nutraceutical companies are playing major role to manage cancer disease by the recommendation of best natural products around the world, most of these natural products are isolated from plant and mushrooms because they contain several chemoprotective agents, which could reduce the chances of development of cancer and protect the cells for further progression. Some nutraceutical supplements might activate the cytotoxic chemotherapeutic effects by the mechanism of cell cycle arrest, cell differentiation procedures and changes in the redox states, but in other, it also elevate the levels of effectiveness of chemotherapeutic mechanism and in results, cancer cell becomes less reactive to chemotherapy. In this review, we have highlighted the prostate cancer and importance of nutraceuticals for the control and management of prostate cancer, and the significance of nutraceuticals to cancer patients during chemotherapy.

MicroRNAs as Predictors of Lung-Cancer Resistance and Sensitivity to Cisplatin

BACKGROUND

Platinum-based chemotherapy, cisplatin (DDP) specifically, is the main strategy for treating lung cancer (LC). However, currently, there is a lack of predictive drug-resistance markers, and there is increased interest in the development of a reliable and sensitive panels of markers for DDP chemotherapy-effectiveness prediction. MicroRNAs represent a perspective pool of markers for chemotherapy effectiveness.

OBJECTIVES

Data on miRNAs associated with LC DDP chemotherapy response are summarized and analyzed.

MATERIALS AND METHODS

A comprehensive review of the data in the literature and an analysis of bioinformatics resources were performed. The gene targets of miRNAs, as well as their reciprocal relationships with miRNAs, were studied using several databases.

RESULTS AND DISCUSSION

The complex analysis of bioinformatics resources and the literature indicated that the expressions of 12 miRNAs have a high predictive potential for LC DDP chemotherapy responses. The obtained information was discussed from the point of view of the main mechanisms of LC chemoresistance.

CONCLUSIONS

An overview of the published data and bioinformatics resources, with respect to the predictive microRNA markers of chemotherapy response, is presented in this review. The selected microRNAs and gene panel have a high potential for predicting LC DDP sensitiveness or DDP resistance as well as for the development of a DDP co-therapy.

Transcriptome Profiling of N7-Methylguanosine Modification of Messenger RNA in Drug-Resistant Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is an aggressive hematological tumor caused by the malignant transformation of myeloid progenitor cells. Although intensive chemotherapy leads to an initial therapeutic response, relapse due to drug resistance remains a significant challenge. In recent years, accumulating evidence has suggested that post-transcriptional methylation modifications are strongly associated with tumorigenesis. However, the mRNA profile of m7G modification in AML and its role in drug-resistant AML are unknown. In this study, we used MeRIP-seq technology to establish the first transcriptome-wide m7G methylome profile for AML and drug-resistant AML cells, and differences in m7G between the two groups were analyzed. In addition, bioinformatics analysis was conducted to explore the function of m7G-specific methylated transcripts. We found significant differences in m7G mRNA modification between AML and drug-resistant AML cells. Furthermore, bioinformatics analysis revealed that differential m7G-modified mRNAs were associated with a wide range of cellular functions. Importantly, down-methylated m7G modification was significantly enriched in ABC transporter-related mRNAs, which are widely recognized to play a key role in multidrug resistance. Our results provide new insights into a novel function of m7G methylation in drug resistance progression of AML.

Benzyl Isothiocyanate-Induced Cytotoxicity via the Inhibition of Autophagy and Lysosomal Function in AGS Cells

Gastric adenocarcinoma is among the top causes of cancer-related death and is one of the most commonly diagnosed carcinomas worldwide. Benzyl isothiocyanate (BITC) has been reported to inhibit the gastric cancer metastasis. In our previous study, BITC induced apoptosis in AGS cells. The purpose of the present study was to investigate the effect of BITC on autophagy mechanism in AGS cells. First, the AGS cells were treated with 5, 10, or 15 μM BITC for 24 h, followed by an analysis of the autophagy mechanism. The expression level of autophagy proteins involved in different steps of autophagy, such as LC3B, p62/SQSTM1, Atg5-Atg12, Beclin1, p-mTOR/mTOR ratio, and class III PI3K was measured in the BITC-treated cells. Lysosomal function was investigated using cathepsin activity and Bafilomycin A1, an autophagy degradation stage inhibitor. Methods including qPCR, western blotting, and immunocytochemistry were employed to detect the protein expression levels. Acridine orange staining and omnicathepsin assay were conducted to analyze the lysosomal function. siRNA transfection was performed to knock down the LC3B gene. BITC reduced the level of autophagy protein such as Beclin 1, class III PI3K, and Atg5-Atg12. BITC also induced lysosomal dysfunction which was shown as reducing cathepsin activity, protein level of cathepsin, and enlargement of acidic vesicle. Overall, the results showed that the BITC-induced AGS cell death mechanism also comprises the inhibition of the cytoprotective autophagy at both initiation and degradation steps.

The Role of microRNAs in Multidrug Resistance of Glioblastoma

Glioblastoma (GBM) is an aggressive brain tumor that develops from neuroglial stem cells and represents a highly heterogeneous group of neoplasms. These tumors are predominantly correlated with a dismal prognosis and poor quality of life. In spite of major advances in developing novel and effective therapeutic strategies for patients with glioblastoma, multidrug resistance (MDR) is considered to be the major reason for treatment failure. Several mechanisms contribute to MDR in GBM, including upregulation of MDR transporters, alterations in the metabolism of drugs, dysregulation of apoptosis, defects in DNA repair, cancer stem cells, and epithelial-mesenchymal transition. MicroRNAs (miRNAs) are a large class of endogenous RNAs that participate in various cell events, including the mechanisms causing MDR in glioblastoma. In this review, we discuss the role of miRNAs in the regulation of the underlying mechanisms in MDR glioblastoma which will open up new avenues of inquiry for the treatment of glioblastoma.

Autophagy responsive intra-intercellular delivery nanoparticles for effective deep solid tumor penetration

Deep tumor cells (cells in the center of solid tumors) play a crucial role in drug tolerance, metastasis, recurrence and microenvironment immune suppression. However, their deep location endows them with an untouched abdomen and makes them refractory to current treatments. Herein, we exploited the characteristic of higher autophagy in deep tumor cells than in superficial tumor cells and designed autophagy-responsive multifunctional nanoparticles (PGN) to enhance drug accumulation in deep tumor cells. PGNs were prepared by densely coating poly (lactic-co-glycolic acid) (PLGA) with cationic autophagy-responsive cell-penetrating peptide (GR9) and anionic 2,3-dimethylmaleic anhydride (DMA)-modified DSPE-PEG. The suitable nanoparticle size (122.4 nm) and charge-neutral surface (0.21 mV) of the NPs enabled long blood circulation. The hydrolysis of surface-anchored anionic DMA in the acidic microenvironment led to the exposure of the GR9 peptide and enhance tumor penetration. Once the PGN arrived in deep tumor cells with strong autophagy, GR9 was cut off by an autophagy shear enzyme, and the nanoparticles remained in the cells to undergo degradation. Furthermore, we prepared docetaxel (DTX) and chloroquine (CQ) loaded d-PGN. CQ inhibits autophagosome fusion with lysosomes, resulting in autophagosome accumulation, which further enhances the sensitivity of d-PGN to autophagy and their deep tumor retention. In vivo experiments showed that drug-loaded d-PGN achieved excellent antitumor efficacy with a peak inhibition rate of 82.1%. In conclusion, autophagy-responsive multifunctional nanoparticles provide a novel potential strategy for solid tumor treatment.

Current Advancements in Antitumor Properties and Mechanisms of Medicinal Components in Edible Mushrooms

Edible and medicinal fungi, a group of eukaryotic organisms with numerous varieties, including Coriolus versicolor, Ganoderma lucidum, Cordyceps sinensis, Pleurotus ostreatus, and Grifola frondosa, have been demonstrated to possess a board range of pharmaceutical properties, including anti-virus, anti-inflammation, and neuroprotection. Moreover, edible and medicinal fungi have been traditionally consumed as food to provide multiple nutrients and as drugs owing to having the activities of invigorating blood circulation, reinforcing the healthy qi, clearing away heat, and eliminating stasis for thousands of years in China. Malignant tumors, well-known as the second leading cause of death globally, accounted for nearly 10 million deaths in 2020. Thus, in-depth exploration of strategies to prevent and treat cancer is extremely urgent. A variety of studies have reported that the main bioactive components of edible and medicinal fungi, mainly polysaccharides and triterpenoids, exhibit diverse anticancer activities via multiple mechanisms, including inhibition of cell proliferation and metastasis, induction of apoptosis and autophagy, reversing multidrug resistance, and regulation of immune responses, thus suggesting their substantial potential in the prevention and treatment of cancer. Our review summarizes the research progress on the anticancer properties of edible and medicinal fungi and the underlying molecular mechanism, which may offer a better understanding of this field. Additionally, few studies have reported the safety and efficacy of extracts from edible and medicinal fungi, which may limit their clinical application. In summary, there is a need to continue to explore the use of those extracts and to further validate their safety and efficacy.

NRBF2 regulates the chemoresistance of small cell lung cancer by interacting with the P62 protein in the autophagy process

Reversing chemotherapy resistance in small cell lung cancer (SCLC) is crucial to improve patient prognosis. The present study aims to investigate the underlying mechanisms in SCLC chemoresistance. We see that nuclear receptor binding factor 2 (NRBF2) is a poor prognostic factor in SCLC. The effects of NRBF2 on chemoresistance were determined in SCLC. The underlying molecular mechanisms of NRBF2 in the autophagy process in SCLC were examined. NRBF2 positively regulated autophagy, leading to drug resistance in SCLC. The MIT domain of NRBF2 directly interacted with the PB1 domain of P62. This interaction increased autophagic P62 body formation, revealing the regulatory role of NRBF2 in autophagy. Notably, NRBF2 was directly modulated by the transcription factor XRCC6. The MIT domain of NRBF2 interacts with the PB1 domain of P62 to regulate the autophagy process, resulting in SCLC chemoresistance. NRBF2 is likely a useful chemotherapy response marker and therapeutic target in SCLC.

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NRBF2 promoted the chemoresistance of SCLC in vitro and in vivo

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The chemoresistance induced by NRBF2 was mediated via autophagy in SCLC

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NRBF2 interacting with P62 contributed to autophagic P62 bodies' formation

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NRBF2 was regulated by XRCC6 via direct binding to the NRBF2 gene promoter

miR-214 Modulates the Growth and Migration of Oral Cancer before and after Chemotherapy through Mediating ULK1

The role of miRNAs as crucial components in carcinogenesis has been well documented. However, whether and how miR-214 influences oral cancer cells' drug resistance remains to be elucidated, and its downstream targets are still under investigation. Hence, this research is aimed at determining miR-214 and ULK1 expression in oral cancer before and after chemotherapy and their correlations with cancer cell growth. Human oral normal epithelial cells and human tongue squamous cell carcinoma CAL-27 cells were cultured to detect miR-214 and ULK1 levels. It was found that before chemotherapy, miR-214 was higher, while ULK1 was underexpressed in CAL-27 cells, versus normal epithelial cells. After chemotherapy, miR-214 decreased obviously in CAL-27 cells, while ULK1 level increased significantly. In addition, autophagy-related genes (Beclin 1, mTOR, and P53) in CAL-27 cells were found to be significantly inhibited before chemotherapy and were obviously increased after chemotherapy. Moreover, to further determine the impacts of miR-214 and ULK1 on oral cancer cell growth after chemotherapy, the two were overexpressed or silenced in CAL-27 cells after transfection. We found that ULK1 could effectively decrease the activity and invasion of CAL-27 cells and increase their apoptosis level, while miR-214 could antagonize its antitumor effect. Therefore, miR-214 can be used as an early prognostic biomarker for oral cancer, and ULK1 is a new candidate therapeutic target.

Present and Future Perspective on PLK1 Inhibition in Cancer Treatment

Polo-like kinase 1 (PLK1) is the principle member of the well conserved serine/threonine kinase family. PLK1 has a key role in the progression of mitosis and recent evidence suggest its important involvement in regulating the G2/M checkpoint, in DNA damage and replication stress response, and in cell death pathways. PLK1 expression is tightly spatially and temporally regulated to ensure its nuclear activation at the late S-phase, until the peak of expression at the G2/M-phase. Recently, new roles of PLK1 have been reported in literature on its implication in the regulation of inflammation and immunological responses. All these biological processes are altered in tumors and, considering that PLK1 is often found overexpressed in several tumor types, its targeting has emerged as a promising anti-cancer therapeutic strategy. In this review, we will summarize the evidence suggesting the role of PLK1 in response to DNA damage, including DNA repair, cell cycle progression, epithelial to mesenchymal transition, cell death pathways and cancer-related immunity. An update of PLK1 inhibitors currently investigated in preclinical and clinical studies, in monotherapy and in combination with existing chemotherapeutic drugs and targeted therapies will be discussed.

Induction of autophagy-dependent ferroptosis to eliminate drug-tolerant human retinoblastoma cells

Carboplatin is the most used first-line drug for the treatment of human retinoblastoma (RB), a rare form of cancer in infancy and childhood. However, the clinical application of carboplatin is restricted due to the emergence of acquired multi-drug resistance (MDR) after long-term treatment. Here, we report a new strategy to eliminate MDR RB cells by inducing autophagy-dependent ferroptosis. Compared with parent cells, carboplatin-resistant human RB cells have higher autophagy activity, which drives the formation of MDR to other chemotherapeutic drugs (e.g., etoposide and vincristine). In addition to confirming the traditional strategy of inhibiting autophagy to overcome MDR, we also establish an approach of inducing selective ferritinophagy to eliminate drug-resistant cells. We evaluate the effectiveness and safety of 4-octyl itaconate, a cell-permeable derivative of the metabolite itaconate, in inducing ferritinophagy-dependent ferroptosis in the treatment of MDR RB cells in vitro and in xenograft mouse models. These findings may provide essential clues for initiating clinical trials that target autophagy-dependent ferroptosis to kill drug-tolerant persistent cells during RB therapy.

Exosomal CTCF Confers Cisplatin Resistance in Osteosarcoma by Promoting Autophagy via the IGF2-AS/miR-579-3p/MSH6 Axis

Cancer-derived exosomes participate in carcinogenesis and progression of cancers, including metastasis and drug-resistance. Of note, CTCF has been suggested to induce drug resistance in various cancers. Herein, we aim to investigate the role of cisplatin- (CDDP-) resistant osteosarcoma- (OS-) derived exosomal CTCF in OS cell resistance to CDDP and its mechanistic basis. Differentially expressed transcription factors, long noncoding RNAs (lncRNAs), miRNAs, and genes in OS were retrieved using bioinformatics approaches. Exosomes were extracted from CDDP-resistant OS cells and then cocultured with parental OS cells, followed by lentiviral transduction to manipulate the expression of CTCF, IGF2-AS, miR-579-3p, and MSH6. We assessed the in vitro and in vivo effects on malignant phenotypes, autophagy, CDDP sensitivity, and tumor formation of OS cells. It was established that CTCF and IGF2-AS were highly expressed in CDDP-resistant OS cells, and the CDDP-resistant OS cell-derived exosomal CTCF enhanced IGF2-AS transcription. CDDP-resistant OS-derived exosomes transmitted CTCF to OS cells and increased CDDP resistance in OS cells by activating an autophagy-dependent pathway. Mechanistically, CTCF activated IGF2-AS transcription and IGF2-AS competitively bound to miR-579-3p to upregulate MSH6 expression. Additionally, the promoting function of exosomal CTCF-mediated IGF2-AS/miR-579-3p/MSH6 in OS cell resistance to CDDP was confirmed in vivo. Taken together, CDDP-resistant OS-derived exosomal CTCF enhanced resistance of OS cells to CDDP via activating the autophagy-dependent pathway, providing a potential therapeutic consideration for OS treatment.

SIRT1 regulates mitotic catastrophe via autophagy and BubR1 signaling

Mitotic catastrophe (MC) is a suppressive mechanism that mediates the elimination of mitosis-deficient cells through apoptosis, necrosis or senescence after M phase block. SIRT1 is involved in the regulation of several cellular processes, including autophagy. However, the relationship between SIRT1 and MC has been largely obscure. Our study highlights that SIRT1 might be involved in the regulation of MC. We have shown that degradation of the SIRT1 protein via proteasome and lysosomal pathway was accompanied by MC induced via BMH-21. Overexpression of SIRT1 alleviated MC by decreasing the proportion of apoptotic and multinuclear cells induced by G2/M block and triggered autophagy whereas knockdown of SIRT1 aggravated MC and repressed autophagy. Furthermore, we found that serum starvation triggered autophagy evidently generated lower MC whereas siRNA of ATG5/7 suppressed autophagy leading to higher MC. ChIP analysis revealed that SIRT1 could bind to the promoter of BubR1, a component of spindle assembly checkpoint (SAC), to upregulate its expression. Overexpression of BubR1 decreased MC whereas knockdown of BubR1 increased it. These results reveal that SIRT1 regulates MC through autophagy and BubR1 signaling, and provide evidence for SIRT1, autophagy and BubR1 being the potential cancer therapeutic targets.

SIRT1 ameliorates renal ischemia-reperfusion injury through suppressing endoplasmic reticulum stress-mediated autophagy

BACKGROUND

Renal ischemia-reperfusion (IR) injury is a therapeutic challenge for surgeons. Sirtuin 1 (SIRT1) is an NAD⁺-dependent deacetylase that plays a vital role in modulating cellular senescence and aging. In this study, we determined whether SIRT1 upregulation could alleviate renal IR injury and the underlying mechanism.

METHODS

A renal IR model was induced in male C57BL/6 mice. Blood urea nitrogen and serum creatinine were evaluated as markers of kidney function, and renal injury was assessed by pathological examination. The inflammatory milieu was analyzed by real-time RT-PCR and myeloperoxidase immunofluorescence assays. Western blotting was used to quantify SIRT1 protein expression, endoplasmic reticulum stress, and autophagy.

RESULTS

SIRT1 was upregulated in renal tissue after IR. Blood analysis and histopathologic examination demonstrated that SIRT1 preserved renal function and reduced renal damage. Further evaluation illustrated that IR induced autophagy and endoplasmic reticulum stress, while SIRT1 upregulation reduced endoplasmic reticulum stress-mediated autophagy levels.

CONCLUSIONS

SIRT1 upregulation protects the kidney against IR-induced injury by inhibiting endoplasmic reticulum stress-mediated autophagy.