Triangular Relationship between p53, Autophagy, and Chemotherapy Resistance

Loss-of-function mutation of REV1 (p.R704Q) mediates cetuximab primary resistance by activating autophagy in RAS-wild type metastatic colorectal cancer

Cetuximab in combination with FOLFIRI/FOLFOX is the standard first-line treatment for patients with RAS wild-type metastatic colorectal cancer (mCRC). However, some patients experience rapid tumor progression after treatment with cetuximab (primary resistance). Our previous research identified a gene mutation, REV1 p.R704Q, which may be a key biomarker for primary cetuximab resistance. This study aimed to study the mechanism of cetuximab resistance caused by REV1 p.R704Q mutation and reveal a novel mechanism to induce cetuximab resistance. Sanger sequencing and multivariate clinical prognostic analysis of 208 patients with mCRC showed that REV1 p.R704Q mutation is an independent risk factor for tumor progression after treatment with cetuximab in patients with RAS wild-type mCRC (Hazard ratio = 2.481, 95 % Confidence interval: 1.389-4.431, P = 0.002). The sensitivity of REV1 p.R704Q mutant cell lines to cetuximab decreased in vitro Cell Counting Kit-8 assay and in vivo subcutaneous tumor model. In vitro, we observed that decreased stability and accelerated degradation of REV1 mutant protein results in REV1 dysfunction, which activated autophagy and mediated cetuximab resistance. These findings suggested that REV1 p.R704Q mutation could predict cetuximab primary resistance in mCRC. REV1 p.R704Q mutation caused decreased stability and degradation of REV1 protein, as well as dysfunction of p.R704Q protein. REV1 p.R704Q mutation activates autophagy and mediates cetuximab resistance; further, inhibition of autophagy could reverse cetuximab resistance.

Curcumin and its anti-colorectal cancer potential: From mechanisms of action to autophagy

Colorectal cancer (CRC) development and progression, one of the most common cancers globally, is supported by specific mechanisms to escape cell death despite chemotherapy, including cellular autophagy. Autophagy is an evolutionarily highly conserved degradation pathway involved in a variety of cellular processes, such as the maintenance of cellular homeostasis and clearance of foreign bodies, and its imbalance is associated with many diseases. However, the role of autophagy in CRC progression remains controversial, as it has a dual function, affecting either cell death or survival, and is associated with cellular senescence in tumor therapy. Indeed, numerous data have been presented that autophagy in cancers serves as an alternative to cell apoptosis when the latter is ineffective or in apoptosis-resistant cells, which is why it is also referred to as programmed cell death type II. Curcumin, one of the active constituents of Curcuma longa, has great potential to combat CRC by influencing various cellular signaling pathways and epigenetic regulation in a safe and cost-effective approach. This review discusses the efficacy of curcumin against CRC in vitro and in vivo, particularly its modulation of autophagy and apoptosis in various cellular pathways. While clinical studies have assessed the potential of curcumin in cancer prevention and treatment, none have specifically examined its role in autophagy. Nonetheless, we offer an overview of potential correlations to support the use of this polyphenol as a prophylactic or co-therapeutic agent in CRC.

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

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

Nanotherapeutics targeting autophagy regulation for improved cancer therapy

The clinical efficacy of current cancer therapies falls short, and there is a pressing demand to integrate new targets with conventional therapies. Autophagy, a highly conserved self-degradation process, has received considerable attention as an emerging therapeutic target for cancer. With the rapid development of nanomedicine, nanomaterials have been widely utilized in cancer therapy due to their unrivaled delivery performance. Hence, considering the potential benefits of integrating autophagy and nanotechnology in cancer therapy, we outline the latest advances in autophagy-based nanotherapeutics. Based on a brief background related to autophagy and nanotherapeutics and their impact on tumor progression, the feasibility of autophagy-based nanotherapeutics for cancer treatment is demonstrated. Further, emerging nanotherapeutics developed to modulate autophagy are reviewed from the perspective of cell signaling pathways, including modulation of the mammalian target of rapamycin (mTOR) pathway, autophagy-related (ATG) and its complex expression, reactive oxygen species (ROS) and mitophagy, interference with autophagosome-lysosome fusion, and inhibition of hypoxia-mediated autophagy. In addition, combination therapies in which nano-autophagy modulation is combined with chemotherapy, phototherapy, and immunotherapy are also described. Finally, the prospects and challenges of autophagy-based nanotherapeutics for efficient cancer treatment are envisioned.

P53/NANOG balance; the leading switch between poorly to well differentiated status in liver cancer cells

Enforcing a well-differentiated state on cells requires tumor suppressor p53 activation as a key player in apoptosis induction and well differentiation. In addition, recent investigations showed a significant correlation between poorly differentiated status and higher expression of NANOG. Inducing the expression of NANOG and decreasing p53 level switch the status of liver cancer cells from well differentiated to poorly status. In this review, we highlighted p53 and NANOG cross-talk in hepatocellular carcinoma (HCC) which is regulated through mitophagy and makes it a novel molecular target to attenuate cancerous phenotype in the management of this tumor.

Adaptations of membrane trafficking in cancer and tumorigenesis

Membrane trafficking, a fundamental cellular process encompassing the transport of molecules to specific organelles, endocytosis at the plasma membrane and protein secretion, is crucial for cellular homeostasis and signalling. Cancer cells adapt membrane trafficking to enhance their survival and metabolism, and understanding these adaptations is vital for improving patient responses to therapy and identifying therapeutic targets. In this Review, we provide a concise overview of major membrane trafficking pathways and detail adaptations in these pathways, including COPII-dependent endoplasmic reticulum (ER)-to-Golgi vesicle trafficking, COPI-dependent retrograde Golgi-to-ER trafficking and endocytosis, that have been found in cancer. We explore how these adaptations confer growth advantages or resistance to cell death and conclude by discussing the potential for utilising this knowledge in developing new treatment strategies and overcoming drug resistance for cancer patients.

Molecular Mechanism of Natural Food Antioxidants to Regulate ROS in Treating Cancer: A Review

Cancer is the second-highest mortality rate disease worldwide, and it has been estimated that cancer will increase by up to 20 million cases yearly by 2030. There are various options of treatment for cancer, including surgery, radiotherapy, and chemotherapy. All of these options have damaging adverse effects that can reduce the patient's quality of life. Cancer itself arises from a series of mutations in normal cells that generate the ability to divide uncontrollably. This cell mutation can happen as a result of DNA damage induced by the high concentration of ROS in normal cells. High levels of reactive oxygen species (ROS) can cause oxidative stress, which can initiate cancer cell proliferation. On the other hand, the cytotoxic effect from elevated ROS levels can be utilized as anticancer therapy. Some bioactive compounds from natural foods such as fruit, vegetables, herbs, honey, and many more have been identified as a promising source of natural antioxidants that can prevent oxidative stress by regulating the level of ROS in the body. In this review, we have highlighted and discussed the benefits of various natural antioxidant compounds from natural foods that can regulate reactive oxygen species through various pathways.

Yiqi Jiedu decoction attenuates radiation injury of spermatogenic cells via suppressing IκBα/NF-κB pathway-induced excessive autophagy and apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

The prescription of Yiqi Jiedu decoction (YQJD) originated from the classic Chinese herbal prescriptions of Danggui Buxue Decoction and Wuzi Yanzong Pill. A previous study has shown that 4 Gy irradiation induced the apoptosis of spermatocytes and revealed autophagosomes in cells exposed to radiation. YQJD decoction has the effect of preventing radiation injury.

AIM OF THE STUDY

We used spermatocytes (GC-2spd cell line) to investigate the relationship between autophagy and apoptosis of spermatogenic cells after radiation, and the mechanisms of YQJD decoction.

MATERIALS AND METHODS

Establish an in vitro radiation injury model by irradiating GC-2spd cells with 60Co γ-rays (4 Gy or 8 Gy). Autophagy agonists, autophagy inhibitors and YQJD were used to intervene cells. Cell apoptosis and inflammatory factors were measured. NF-κB localization was observed by immunofluorescence. Autophagy and apoptosis-related proteins and IκBα/NF-κB pathway factors were detected.

RESULTS

Ionizing radiation promoted the growth of spermatogenic autophagosomes. After radiation, NF-κB was translocated to the nucleus, inflammatory factors were secreted, and IκBα/NF-κB pathway was activated, which promoted autophagy and apoptosis. YQJD decoction can inhibit the phosphorylation of IκBα/NF-κB pathway related factors, regulate the expression of Beclin-1 and Bcl-2 proteins, and inhibit the occurrence of autophagy and apoptosis of irradiated spermatocyte.

CONCLUSIONS

The research results indicate that ionizing radiation can activate the IκBα/NF-κB signaling pathway in spermatocytes, promote cell autophagy and apoptosis by regulating the expression of Beclin-1 and Bcl-2 factors. The YQJD decoction inhibits the IκBα/NF-κB signaling pathway so as to regulate Beclin-1 and Bcl-2.

Anti-IL-8 monoclonal antibodies inhibits the autophagic activity and cancer stem cells maintenance within breast cancer tumor microenvironment

BACKGROUND

Breast cancer tumor microenvironment (TME) is a promising target for immunotherapy. Autophagy, and cancer stem cells (CSCs) maintenance are essential processes involved in tumorigenesis, tumor survival, invasion, and treatment resistance. Overexpression of angiogenic chemokine interleukin-8 (IL-8) in breast cancer TME is associated with oncogenic signaling pathways, increased tumor growth, metastasis, and poor prognosis.

OBJECTIVE

Thus, we aimed to investigate the possible anti-tumor effect of neutralizing antibodies against IL-8 by evaluating its efficacy on autophagic activity and breast CSC maintenance.

METHODS

IL-8 monoclonal antibody supplemented tumor tissue culture systems from 15 females undergoing mastectomy were used to evaluate the expression of LC3B as a specific biomarker of autophagy and CD44, CD24 as cell surface markers of breast CSCs using immunofluorescence technique.

RESULTS

Our results revealed that anti-IL-8 mAb significantly decreased the level of LC3B in the cultured tumor tissues compared to its non-significant decrease in the normal breast tissues.Anti-IL-8 mAb also significantly decreased the CD44 expression in either breast tumors or normal cultured tissues. While it caused a non-significant decrease in CD24 expression in cultured breast tumor tissue and a significant decrease in its expression in the corresponding normal ones.

CONCLUSIONS

Anti-IL-8 monoclonal antibody exhibits promising immunotherapeutic properties through targeting both autophagy and CSCs maintenance within breast cancer TME.

Highly Similar Tetramerization Domains from the p53 Protein of Different Mammalian Species Possess Varying Biophysical, Functional and Structural Properties

The p53 protein is a transcriptional regulatory factor and many of its functions require that it forms a tetrameric structure. Although the tetramerization domain of mammalian p53 proteins (p53TD) share significant sequence similarities, it was recently shown that the tree shrew p53TD is considerably more thermostable than the human p53TD. To determine whether other mammalian species display differences in this domain, we used biophysical, functional, and structural studies to compare the properties of the p53TDs from six mammalian model organisms (human, tree shrew, guinea pig, Chinese hamster, sheep, and opossum). The results indicate that the p53TD from the opossum and tree shrew are significantly more stable than the human p53TD, and there is a correlation between the thermostability of the p53TDs and their ability to activate transcription. Structural analysis of the tree shrew and opossum p53TDs indicated that amino acid substitutions within two distinct regions of their p53TDs can dramatically alter hydrophobic packing of the tetramer, and in particular substitutions at positions corresponding to F341 and Q354 of the human p53TD. Together, the results suggest that subtle changes in the sequence of the p53TD can dramatically alter the stability, and potentially lead to important changes in the functional activity, of the p53 protein.

Chloroquine enhances the efficacy of chemotherapy drugs against acute myeloid leukemia by inactivating the autophagy pathway

Current therapy for acute myeloid leukemia (AML) is largely hindered by the development of drug resistance of commonly used chemotherapy drugs, including cytarabine, daunorubicin, and idarubicin. In this study, we investigated the molecular mechanisms underlying the chemotherapy drug resistance and potential strategy to improve the efficacy of these drugs against AML. By analyzing data from ex vivo drug-response and multi-omics profiling public data for AML, we identified autophagy activation as a potential target in chemotherapy-resistant patients. In THP-1 and MV-4-11 cell lines, knockdown of autophagy-regulated genes ATG5 or MAP1LC3B significantly enhanced AML cell sensitivity to the chemotherapy drugs cytarabine, daunorubicin, and idarubicin. In silico screening, we found that chloroquine phosphate mimicked autophagy inactivation. We showed that chloroquine phosphate dose-dependently down-regulated the autophagy pathway in MV-4-11 cells. Furthermore, chloroquine phosphate exerted a synergistic antitumor effect with the chemotherapy drugs in vitro and in vivo. These results highlight autophagy activation as a drug resistance mechanism and the combination therapy of chloroquine phosphate and chemotherapy drugs can enhance anti-AML efficacy.

Tumor metabolism rewiring in epithelial ovarian cancer

The mortality rate of epithelial ovarian cancer (EOC) remains the first in malignant tumors of the female reproductive system. The characteristics of rapid proliferation, extensive implanted metastasis, and treatment resistance of cancer cells require an extensive metabolism rewiring during the progression of cancer development. EOC cells satisfy their rapid proliferation through the rewiring of perception, uptake, utilization, and regulation of glucose, lipids, and amino acids. Further, complete implanted metastasis by acquiring a superior advantage in microenvironment nutrients competing. Lastly, success evolves under the treatment stress of chemotherapy and targets therapy. Understanding the above metabolic characteristics of EOCs helps to find new methods of its treatment.

p53 at the Crossroads between Doxorubicin-Induced Cardiotoxicity and Resistance: A Nutritional Balancing Act

Doxorubicin (DOX) is a highly effective chemotherapeutic drug, but its long-term use can cause cardiotoxicity and drug resistance. Accumulating evidence demonstrates that p53 is directly involved in DOX toxicity and resistance. One of the primary causes for DOX resistance is the mutation or inactivation of p53. Moreover, because the non-specific activation of p53 caused by DOX can kill non-cancerous cells, p53 is a popular target for reducing toxicity. However, the reduction in DOX-induced cardiotoxicity (DIC) via p53 suppression is often at odds with the antitumor advantages of p53 reactivation. Therefore, in order to increase the effectiveness of DOX, there is an urgent need to explore p53-targeted anticancer strategies owing to the complex regulatory network and polymorphisms of the p53 gene. In this review, we summarize the role and potential mechanisms of p53 in DIC and resistance. Furthermore, we focus on the advances and challenges in applying dietary nutrients, natural products, and other pharmacological strategies to overcome DOX-induced chemoresistance and cardiotoxicity. Lastly, we present potential therapeutic strategies to address key issues in order to provide new ideas for increasing the clinical use of DOX and improving its anticancer benefits.

Natural products targeting signaling pathways associated with regulated cell death in gastric cancer: Recent advances and perspectives

Gastric cancer (GC) is one of the most serious gastrointestinal malignancies with high morbidity and mortality. The complexity of GC process lies in the multi-phenotypic linkage regulation, in which regulatory cell death (RCD) is the core link, which largely dominates the fate of GC cells and becomes a key determinant of GC development and prognosis. In recent years, increasing evidence has been reported that natural products can prevent and inhibit the development of GC by regulating RCDs, showing great therapeutic potential. In order to further clarify its key regulatory characteristics, this review focused on specific expressions of RCDs, combined with a variety of signaling pathways and their crosstalk characteristics, sorted out the key targets and action rules of natural products targeting RCD. It is highlighted that a variety of core biological pathways and core targets are involved in the decision of GC cell fate, including the PI3K/Akt signaling pathway, MAPK-related signaling pathways, p53 signaling pathway, ER stress, Caspase-8, gasdermin D (GSDMD), and so on. Moreover, natural products target the crosstalk of different RCDs by modulating above signaling pathways. Taken together, these findings suggest that targeting various RCDs in GC with natural products is a promising strategy, providing a reference for further clarifying the molecular mechanism of natural products treating GC, which warrants further investigations in this area.

Autophagy in Cancer Progression and Therapeutics

Autophagy is a catabolic process that is necessary for cellular homeostasis maintenance [...].

Xiaojianzhong decoction prevents gastric precancerous lesions in rats by inhibiting autophagy and glycolysis in gastric mucosal cells

BACKGROUND

Gastric precancerous lesions (GPL) precede the development of gastric cancer (GC). They are characterized by gastric mucosal intestinal metaplasia and dysplasia caused by various factors such as inflammation, bacterial infection, and injury. Abnormalities in autophagy and glycolysis affect GPL progression, and their effective regulation can aid in GPL treatment and GC prevention. Xiaojianzhong decoction (XJZ) is a classic compound for the treatment of digestive system diseases in ancient China which can inhibit the progression of GPL. However, its specific mechanism of action is still unclear.

AIM

To investigate the therapeutic effects of XJZ decoction on a rat GPL model and the mechanisms underlying its effects on autophagy and glycolysis regulation in GPLs.

METHODS

Wistar rats were randomly divided into six groups of five rats each and all groups except the control group were subjected to GPL model construction for 18 wk. The rats’ body weight was monitored every 2 wk starting from the beginning of modeling. Gastric histopathology was examined using hematoxylin-eosin staining and Alcian blue-periodic acid-Schiff staining. Autophagy was observed using transmission electron microscopy. The expressions of autophagy, hypoxia, and glycolysis related proteins in gastric mucosa were detected using immunohistochemistry and immunofluorescence. The expressions of the following proteins in gastric tissues: B cell lymphoma/Leukemia-2 and adenovirus E1B19000 interacting protein 3 (Bnip-3), microtubule associated protein 1 light chain 3 (LC-3), moesin-like BCL2-interacting protein 1 (Beclin-1), phosphatidylinositol 3-kimase (PI3K), protein kinase B (AKT), mammalian target of rapamycin (mTOR), p53, AMP-activated protein kinase (AMPK), and Unc-51 like kinase 1 (ULK1) were detected using western blot. The relative expressions of autophagy, hypoxia, and glycolysis related mRNA in gastric tissues was detected using reverse transcription-polymerase chain reaction.

RESULTS

Treatment with XJZ increased the rats’ body weight and improved GPL-related histopathological manifestations. It also decreased autophagosome and autolysosome formation in gastric tissues and reduced Bnip-3, Beclin-1, and LC-3II expressions, resulting in inhibition of autophagy. Moreover, XJZ down-regulated glycolysis-related monocarboxylate transporter (MCT1), MCT4, and CD147 expressions. XJZ prevented the increase of autophagy level by decreasing gastric mucosal hypoxia, activating the PI3K/AKT/mTOR pathway, inhibiting the p53/AMPK pathway activation and ULK1 Ser-317 and Ser-555 phosphorylation. In addition, XJZ improved abnormal gastric mucosal glucose metabolism by ameliorating gastric mucosal hypoxia and inhibiting ULK1 expression.

CONCLUSION

This study demonstrates that XJZ may inhibit autophagy and glycolysis in GPL gastric mucosal cells by improving gastric mucosal hypoxia and regulating PI3K/AKT/mTOR and p53/ AMPK/ULK1 signaling pathways, providing a feasible strategy for the GPL treatment.

Chloroquine induces transitory attenuation of proliferation of human lung cancer cells through regulation of mutant P53 and YAP

BACKGROUND

Non-small cell lung carcinoma (NSCLC) is the most common cause of cancer-associated deaths worldwide. Though recent development in targeted therapy has improved NSCLC prognosis, yet there is an unmet need to identify novel causative factors and appropriate therapeutic regimen against NSCLCs.

METHODS AND RESULTS

In this study, we identify key molecular factors de-regulated in NSCLCs. Analyze their expression by real-time PCR and immunoblot; map their localization by immuno-fluorescence microscopy. We further propose an FDA approved drug, chloroquine (CQ) that affects the function of the molecular factors and hence can be repurposed as a therapeutic strategy against NSCLCs. Available NSCLC mutation data reflects a high probabilistic chance of patients harboring a p53 mutation, especially a gain of function (GOF)-R273H mutation. The GOF-P53 mutation enables the P53 protein to potentially interact with non-canonical protein partners facilitating oncogenesis. In this context, analysis of existing transcriptomic data from R273H-P53 expressing cells shows a concomitant up-regulation of Yes-associated protein (YAP) transcriptional targets and its protein partner TEAD1 in NSCLCs, suggesting a possible link between R273H-P53 and YAP. We therefore explored the inter-dependence of R273H-P53 and YAP in NSCLC cells. They were found to co-operatively regulate NSCLC proliferation. Genetic or pharmacological inhibition of YAP and GOF-P53 resulted in sensitization of NSCLC cells. Further analysis of pathways controlled by GOF-P53 and YAP showed that they positively regulate the cellular homeostatic process- autophagy to mediate survival. We hence postulated that a modulation of autophagy might be a potent strategy to curb proliferation. In accordance to above, autophagy inhibition, especially with the FDA-approved drug- chloroquine (CQ) resulted in cytoplasmic accumulation and reduced transcriptional activity of GOF-P53 and YAP, leading to growth arrest of NSCLC cells.

CONCLUSION

Our study highlights the importance of GOF-P53 and YAP in NSCLC proliferation and proposes autophagy inhibition as an efficient strategy to attenuate NSCLC tumorigenesis.

PRIMA-1 inhibits Y220C p53 amyloid aggregation and synergizes with cisplatin in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide. Although many therapeutic options are available, several factors, including the presence of p53 mutations, impact tumor development and therapeutic resistance. TP53 is the second most frequently mutated gene in HCC, comprising more than 30% of cases. Mutations in p53 result in the formation of amyloid aggregates that promote tumor progression. The use of PRIMA-1, a small molecule capable of restoring p53, is a therapeutic strategy to pharmacologically target the amyloid state mutant p53. In this study, we characterize an HCC mutant p53 model for the study of p53 amyloid aggregation in HCC cell lines, from in silico analysis of p53 mutants to a 3D-cell culture model and demonstrate the unprecedented inhibition of Y220C mutant p53 aggregation by PRIMA-1. In addition, our data show beneficial effects of PRIMA-1 in several "gain of function" properties of mutant-p53 cancer cells, including migration, adhesion, proliferation, and drug resistance. We also demonstrate that the combination of PRIMA-1 and cisplatin is a promising approach for HCC therapy. Taken together, our data support the premise that targeting the amyloid-state of mutant p53 may be an attractive therapeutic approach for HCC, and highlight PRIMA-1 as a new candidate for combination therapy with cisplatin.

Resistance Mechanism of Acute Myeloid Leukemia Cells Against Daunorubicin and Cytarabine: A Literature Review

Acute myeloid leukemia (AML) is a hematological malignancy commonly found in adult patients. Low overall survival and resistance to therapy are the main issues in AML. The first line of treatment for AML chemotherapy is the induction phase, namely, the phase to induce remission by administering a combination of daunorubicin (DNR) for three days followed by administration of cytarabine (Ara-C) with continuous infusion for seven days, which is referred to as "3 + 7." Such induction therapy has been the standard therapy for AML for the last four decades. This review article is made to discuss daunorubicin and cytarabine from their chemical structure, pharmacodynamics, pharmacokinetics, and mechanisms of resistance in AML.

Novel Platinum Nanoclusters Activate PI3K/AKT/mTOR Signaling Pathway-Mediated Autophagy for Cisplatin-Resistant Ovarian Cancer Therapy

Platinum (Pt)-based chemotherapy drugs such as cisplatin are the first line and core options for the treatment of ovarian cancer (OC), while cisplatin resistance has a worse prognosis and low 5 year survival rate for patients. Chemotherapeutic drugs synthesized from nanomaterials have shown great potential in biomedicine; however, research into their application for OC resistance is rarely discussed. This study is proposed to elucidate the anti-tumor effects of polyethylenimine (PEI)-caged platinum nanoclusters (Pt NCs) on cisplatin-resistant OC. The results of confocal microscopy showed that Pt NCs entered cisplatin-resistant OC cells dose-dependently and aggregated both in the cytoplasm and inside the nucleus. Subsequently, according to the results of CCK8 assay, wound healing assay, clone formation assay, Transwell assay, Ki-67 immunofluorescence assay, and flow cytometry assay, the proliferation and migration of cisplatin-resistant OC cells were inhibited by Pt NCs, as well as their apoptosis was promoted. In addition, we validated the anti-tumor effect of Pt NCs on regulating autophagy via monodansylcadaverine (MDC) staining, transmission electron microscopy observation of the autophagic ultrastructure, LC3-II-GFP and P62-GFP adenovirus single-label immunofluorescence, and western blotting; meanwhile, the role of Pt NCs in adjusting autophagy through modulation of the PI3K-AKT-mTOR signaling was verified. Based on these results, it appears that cisplatin-resistant OC cells can undergo apoptosis when Pt NCs activate autophagy by inhibiting the PI3K/AKT/mTOR pathway, exhibiting a promising potential of Pt NCs in the development of a novel chemotherapeutic agent for patients suffering from cisplatin-resistant OC.

Apoptotic effect of sulfated galactofucan from marine macroalga Turbinaria ornata on hepatocellular and ductal carcinoma cells

Tumor protein or cellular tumor antigen p53, is considered a critical transcriptional regulation factor, which can suppress the growth of tumor cells by activating other functional genes. The current study appraised the p53 activation pathways, which could be used as an alternative therapeutic strategy for the treatment of hepatocellular and ductal carcinoma. Algal polysaccharides have been used as emerging sources of bioactive natural pharmacophores. A sulfated galactofucan characterized as [→1)-O-4-sulfonato-α-fucopyranose-(3 → 1)-α-fucopyranose-(3→] as the main branch with [→1)-6-O-acetyl-β-galactopyranose-(4→] as side chain isolated from marine macroalga Turbinaria ornata exhibited prospective apoptosis on HepG2 (hepatocellular carcinoma) and MCF7 (ductal carcinoma) cells. Annexin V-fluorescein isothiocyanate-propidium iodide study displayed higher early apoptosis in MCF7 and HepG2 cell lines (56 and 24.2%, respectively) treated with TOP-3 (at IC50 concentration) than those administered with standard camptothecin. Upregulation of the p53 gene expression was perceived in TOP-3 treated HepG2 and MCF7 cells.

Unravelling the roles of Autophagy in OSCC: A renewed perspective from mechanisms to potential applications

Oral squamous cell carcinoma (OSCC) is associated with a low survival rate and a high disability rate, making it a serious health burden, particularly in Southeast Asian countries. Therefore, improvements in the diagnosis, treatment, and prognosis prediction of OSCC are highly warranted. Autophagy has a significant impact on cancer development. Studies on autophagy in various human cancers have made outstanding contributions; however, the relationship between autophagy and OSCC remains to be explored. This review highlights the roles of autophagy in OSCC and discusses the relationship between autophagy and Epithelial–mesenchymal transition. Considering the lack of OSCC biomarkers, we focus on the studies involving OSCC-related bioinformatics analysis and molecular targets. Based on some classical targets, we summarize several key autophagy-related biomarkers with a considerable potential for clinical application, which may become the hotspot of OSCC research. In conclusion, we elaborate on the interrelationship between autophagy and OSCC and highlight the shortcomings of current studies to provide insights into the potential clinical strategies.

Phosphoinositide species and filamentous actin formation mediate engulfment by senescent tumor cells

Cancer cells survive chemotherapy and cause lethal relapse by entering a senescent state that facilitates expression of many phagocytosis/macrophage-related genes that engender a novel cannibalism phenotype. We used biosensors and live-cell imaging to reveal the basic steps and mechanisms of engulfment by senescent human and mouse tumor cells. We show filamentous actin in predator cells was localized to the prey cell throughout the process of engulfment. Biosensors to various phosphoinositide (PI) species revealed increased concentration and distinct localization of predator PI(4) P and PI(4,5)P2 at the prey cell during early stages of engulfment, followed by a transient burst of PI(3) P before and following internalization. PIK3C2B, the kinase responsible for generating PI(3)P, was required for complete engulfment. Inhibition or knockdown of Clathrin, known to associate with PIK3C2B and PI(4,5)P2, severely impaired engulfment. In sum, our data reveal the most fundamental cellular processes of senescent cell engulfment, including the precise localizations and dynamics of actin and PI species throughout the entire process.

Multiple Strikes Achieve Remarkable Tumor-Inhibition Efficiency via Multi-mechanism Combination

Breast cancer treatment has been challenging all the time because cancer cells have multiple signaling pathways; so, breast cancer still remains a threat to the lives and health of many patients. While common single drug therapies inhibit only one pathway, the combination of multiple mechanisms offers the potential to simultaneously suppress multiple targets and pathways to kill cancer cells more effectively. It is reported that autophagy caused by autophagy inducers and apoptosis caused by some chemotherapeutic drugs can promote ferroptosis to some extent; herein, we combined these three pathways and constructed a multifunctional dual-responsive release nanosystem of Rap@mFe₃O₄-DOX-HA that achieved the ferroptosis-autophagy-apoptosis synergistic effect for cancer treatment. Mesoporous Fe₃O₄ (mFe₃O₄) was set as the carrier and can also release Fe ions for ferroptosis, the autophagy inducer rapamycin (Rap) was wrapped in the carrier to trigger autophagy, and the chemotherapeutic drug doxorubicin (DOX) was used as the apoptosis inducer. At the tumor site, the prepared Rap@mFe₃O₄-DOX-HA nanoparticles split and released DOX/Rap in response to H⁺/GSH. From in vivo and in vitro studies, it was found that Rap@mFe₃O₄-DOX-HA nanoparticles effectively inhibited the migration of 4T1 cells, furthermore, they struck cancer cells through multiple pathways and greatly improved the anti-tumor effect. Therefore, the strategy of multi-mechanism combination achieved a therapeutic effect of 1 + 1 > 2.

Construction and validation of an autophagy-related long non-coding RNA signature to predict the prognosis of kidney renal papillary cell carcinoma

To identify the autophagy-related long non-coding RNAs (ARlncRNAs) associated with the prognosis of kidney renal papillary cell carcinoma (KIRP), thereby establishing a clinical prognostic model. The gene expression matrix and clinical survival information of patients with KIRP were downloaded from The Cancer Genome Atlas database, and were divided into the training and testing groups. ARlncRNAs associated with the KIRP prognosis were analyzed by univariate, Least Absolute Shrinkage and Selection Operator (LASSO(, and multivariate Cox regression to construct a signature. We combined clinical factors associated with the prognosis with ARlncRNAs to establish a prognostic model of patients with KIRP. A nomogram was established to predict 1-year, 3-year, and 5-year survival of patients with KIRP. Besides, we built the lncRNA-messenger RNA co-expression network and used Kyoto Encyclopedia of Genes and Genomes and Gene Set Enrichment Analysis to detect the biological functions of ARlncRNAs. LEF1-AS1, CU634019.6, C2orf48, AC027228.2, and AC107464.3 were identified. A prognosis-related ARlncRNAs signature was constructed in the training group and validated in the testing group. Patients with KIRP with a low risk score had significantly longer survival time than those with a high risk score. The risk score significantly affected the prognosis of patients, thereby being used for modeling. The area under the receiver operating characteristic curve values of 1-year, 3-year, and 5-year overall survival were 0.80, 0.78, and 0.84 in the training group, respectively. The signature had high concordance index and good accuracy in predicting the prognosis, which were confirmed by the nomogram. The prognosis-related ARlncRNAs signature we identified had a more accurate prediction for the prognosis of patients with KIRP.

Therapy resistance: opportunities created by adaptive responses to targeted therapies in cancer

Normal cells explore multiple states to survive stresses encountered during development and self-renewal as well as environmental stresses such as starvation, DNA damage, toxins or infection. Cancer cells co-opt normal stress mitigation pathways to survive stresses that accompany tumour initiation, progression, metastasis and immune evasion. Cancer therapies accentuate cancer cell stresses and invoke rapid non-genomic stress mitigation processes that maintain cell viability and thus represent key targetable resistance mechanisms. In this Review, we describe mechanisms by which tumour ecosystems, including cancer cells, immune cells and stroma, adapt to therapeutic stresses and describe three different approaches to exploit stress mitigation processes: (1) interdict stress mitigation to induce cell death; (2) increase stress to induce cellular catastrophe; and (3) exploit emergent vulnerabilities in cancer cells and cells of the tumour microenvironment. We review challenges associated with tumour heterogeneity, prioritizing actionable adaptive responses for optimal therapeutic outcomes, and development of an integrative framework to identify and target vulnerabilities that arise from adaptive responses and engagement of stress mitigation pathways. Finally, we discuss the need to monitor adaptive responses across multiple scales and translation of combination therapies designed to take advantage of adaptive responses and stress mitigation pathways to the clinic.

Hsa_circ_0072309 enhances autophagy and TMZ sensitivity in glioblastoma

Aims

Circular RNAs have been reported to play key roles in the progression of various cancers, including gliomas. The present study was designed to investigate the role of hsa_circ_0072309 in autophagy and temozolomide (TMZ) sensitivity in glioblastoma (GBM).

Methods

The effect of hsa_circ_0072309 on autophagy and TMZ sensitivity were examined by GFP‐RFP‐LC3, transmission electron microscopy(TEM), flow cytometry, Western blot, and immunofluorescence. The mechanism of hsa_circ_0072309 regulating p53 signaling pathway was analyzed using Western blot, IP, and rescue experiments.

Results

Low hsa_circ_0072309 expression predicts poor prognosis for glioma patients. The regulation of hsa_circ_0072309 on autophagy and TMZ sensitivity depends on the status of p53. Hsa_circ_0072309 promoted autophagy by p53 signaling pathway and enhanced sensitivity of glioblastoma to temozolomide (TMZ) in p53 wild‐type GBM, but not in p53 mutant GBM. Hsa_circ_0072309 inhibits p53 ubiquitination and increases the stability of p53 protein in the context of p53 wild‐type. MiR‐100 mediates hsa_circ_0072309 regulating p53. P53 inhibitor or autophagy inhibitor could reverse the effect of hsa_circ_0072309 on TMZ sensitivity in p53 wild‐type GBM.

Conclusions

This study revealed a function of hsa_circ_0072309 promoting autophagy by p53 signaling pathway and enhancing TMZ sensitivity. These findings demonstrated that hsa_circ_0072309 may be a potential and promising target in designing the treatment strategy for GBM.

Targeting autophagy in colorectal cancer: An update on pharmacological small-molecule compounds

Autophagy, an evolutionarily highly conserved cellular degradation process, plays the Janus role (either cytoprotective or death-promoting) in colorectal cancer, so the targeting of several key autophagic pathways with small-molecule compounds may be a new therapeutic strategy. In this review, we discuss autophagy-associated cell death pathways and key cytoprotective autophagy pathways in colorectal cancer. Moreover, we summarize a series of small-molecule compounds that have the potential to modulate autophagy-associated cell death or cytoprotective autophagy for therapeutic purposes. Taken together, these findings demonstrate the Janus role of autophagy in colorectal cancer, and shed new light on the exploitation of a growing number of small-molecule compounds to target autophagy in future cancer drug discovery.

Activation of Esterase D by FPD5 Inhibits Growth of A549 Lung Cancer Cells via JAB1/p53 Pathway

Esterase D (ESD) is widely distributed in mammals, and it plays an important role in drug metabolism, detoxification, and biomarkers and is closely related to the development of tumors. In our previous work, we found that a chemical small-molecule fluorescent pyrazoline derivative, FPD5, an ESD activator, could inhibit tumor growth by activating ESD, but its molecular mechanism is still unclear. Here, by using RNA interference (RNAi), andco-immunoprecipitation techniques, we found that ESD suppressed the nucleus exportation of p53 through reducing the interaction between p53 and JAB1. The protein level of p53 in the nucleus was upregulated and the downstream targets of p53 were found by Human Gene Expression Array. p53 inhibited the expression of CDCA8 and CDC20. Lastly, the cell cycle of A549 cells was arrested at the G0/G1 phase. Together, our data suggest that ESD inhibited the cancer cell growth by arresting the cell cycle of A549 cells via the JAB1/p53 signaling pathway. Our findings provide a new insight into how to inhibit the growth of lung cancer with the activation of ESD by FPD5.

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.

S-20, a steroidal saponin from the berries of black nightshade, exerts anti-multidrug resistance activity in K562/ADR cells through autophagic cell death and ERK activation

Multidrug resistance (MDR) is a major cause of chemotherapy failure. Adriamycin (ADR) has been widely used to treat cancer, however, as a substrate of the adenosine triphosphate binding cassette (ABC) transporter, it is easy to develop drug resistance during the treatment. Here, we demonstrated that steroidal saponin S-20 isolated from the berries of black nightshade has comparable cytotoxicity in ADR-sensitive and resistant K562 cell lines. Autophagy is generally considered to be a protective mechanism to mediate MDR during treatment. However, we found that S-20-induced cell death in K562/ADR is associated with autophagy. We further explored the underlying mechanisms and found that S-20 induces caspase-dependent apoptosis in ADR-sensitive and resistant K562 cell lines. Most importantly, S-20-induced autophagy activates the ERK pathway and then inhibits the expression of drug resistance protein, which is the main reason to overcome K562/ADR resistance, rather than apoptosis. Taken together, our findings emphasize that S-20 exerts anti-multidrug resistance activity in K562/ADR cells through autophagic cell death and ERK activation, which may be considered as an effective strategy.

Autophagy Modulation and Cancer Combination Therapy: A Smart Approach in Cancer Therapy

The autophagy pathway is the process whereby cells keep cellular homeostasis and respond to stress via recycling their damaged cellular proteins, organelles, and other cellular components. In the context of cancer, autophagy is a dual-edge sword pro- and anti-tumorigenic role depending on the oncogenic context and stage of tumorigenesis. Cancer cells have a higher dependency on autophagy compared with normal cells because of cellular damages and high demands for energy. The carbon, nitrogen, and molecular oxygen are building blocks for highly proliferative cancer cells which extremely depend on glutaminolysis and aerobic glycolysis; when a cancer cell is restricted to glucose and glutamine, it initiates to activate a stress response pathway using autophagy. Oncogenic tyrosine kinases (OncTKs) and receptor tyrosine kinases (RTKs) activation result in autophagy modulation through activation of the PI3K/AKT/mTORC1 and RAS/MAPK signaling pathways. Targeted inhibition of tyrosine kinases (TKs) and RTKs have recently been considered as cancer therapy but drug resistance and cancer relapse continue to be a major limitation of tyrosine kinase inhibitors (TKIs). Manipulation of autophagy pathway along with TKIs may be a promising strategy to circumvent unknown existing drug-resistance mechanisms that may emerge in a treated patient. In this way, clinical trials are ongoing to modulate autophagy to treat cancer. This review aims to summarize the combination therapy of autophagy affecting compounds with anticancer drugs which target cell signaling pathways, metabolism mechanisms, and epigenetics modification to improve therapeutic efficacy against cancers.

Biosynthetic cell membrane vesicles to enhance TRAIL-mediated apoptosis driven by photo-triggered oxidative stress

Due to the tumor-specificity and limited side effects, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) shows great potential in cancer treatments. However, the short half-life of TRAIL protein and the poor...

Extracellular HMGB1 interacts with RAGE and promotes chemoresistance in acute leukemia cells

Background

Nowadays, acute leukemia (AL) among children has favorable outcome, yet some of them get refractory or relapse mainly due to drug resistance. High-mobility group box 1 (HMGB1) has been proven to have a important role in drug resistance via upregulation of autophagy after chemotherapy treatment in acute leukemia. However, the mechanism how extracellular HMGB1 acts on AL cells and leads to chemoresistance remains elusive.

Method

CCK8 was used to examine the toxicity of chemotherapeutic drug. Elisa was performed to detect the release of HMGB1. Western blot and mRFP-GFP-LC3 adenoviral particles as well as transmission electron microscopy were used to detect the autophagy flux. Western blot and flow cytometry were applied to evaluate the apoptosis. qPCR and western blot were conducted to detect the expression of drug efflux protein. Lentivirus infection was applied to knock down RAGE. In addition, T-ALL NOD/SCID mice xenograft model was used to observe the effect of inhibiting HMGB1/RAGE axis.

Results

We found that extracellular HMGB1 do upregulate autophagy and in the meantime downregulate apoptosis, primarily through interaction with receptor for advanced glycation end products (RAGE). Suppression of RAGE by RNA interference alleviated the level of autophagy and enhanced apoptosis. What’s more, HMGB1/RAGE induced autophagy was associated with the activation of ERK1/2 and decreased phosphorylation of mammalian target of rapamycin (mTOR), while HMGB1/RAGE limited apoptosis in a Bcl-2-regulated way mediated by P53. On the other hand, we found that HMGB1/RAGE activated the NF-κB pathway and promoted the expression of P-glycation protein (P-gp) as well as multidrug resistance-associated protein (MRP), both are ATP-binding cassette transporters. In vivo experiment, we found that blocking HMGB1/RAGE axis do have a mild pathological condition and a better survival in T-ALL mice.

Conclusion

HMGB1/RAGE have a important role in drug resistance after chemotherapy treatment, mainly by regulating autophagy and apoptosis as well as promoting the expression of drug efflux protein such as P-gp and MRP. HMGB1/RAGE might be a promising target to cure AL, especially for those met with relapse and refractory.

Targeting ERK induced cell death and p53/ROS-dependent protective autophagy in colorectal cancer

In recent years, many studies have shown that autophagy plays a vital role in the resistance of tumor chemotherapy. However, the interaction between autophagy and cell death has not yet been clarified. In this study, a new specific ERK inhibitor CC90003 was found to suppress colorectal cancer growth by inducing cell death both in vitro and in vivo. Studies have confirmed that higher concentrations of ROS leads to autophagy or cell death. In this research, the role of CC90003-induced ROS was verified. But after inhibiting ROS by two kinds of ROS inhibitors NAC and SFN, the autophagy induced by CC90003 decreased, while cell death strengthened. In parallel, protective autophagy was also induced, while in a p53-dependent manner. After silencing p53 or using the p53 inhibitor PFTα, the autophagy induced by CC90003 was weakened and the rate of cell death increases. Therefore, we confirmed that CC90003 could induce autophagy by activating ROS/p53. Furthermore, in the xenograft mouse model, the effect was obtained remarkably in the combinational treatment group of CC90003 plus CQ, comparing with that of the single treatment groups. In a word, our results demonstrated that targeting ERK leads to cell death and p53/ROS-dependent protective autophagy simultaneously in colorectal cancer, which offers new potential targets for clinical therapy.

In Vitro Assessment of the Role of p53 on Chemotherapy Treatments in Neuroblastoma Cell Lines

Neuroblastoma is the most frequent malignant extracranial solid tumor of infancy. The overall objective of this work consists of determining the presence of alterations in the p53/MDM2/p14ARF signaling pathway in neuroblastoma cell lines and deciphering their possible relationship with resistance to known antineoplastic drugs and to differentiation agents. Firstly, we characterized 10 neuroblastoma cell lines for alterations at the p53/MDM2/p14ARF signaling pathway by analysis of TP53 point mutations, MYCN and MDM2 amplification, and p14ARF methylation, homozygous deletions, and expression. Secondly, we chose SK-N-FI (mutated at TP53) and SK-N-Be(2) (wild-type TP53) cell lines, treated them with chemotherapeutic agents (doxorubicin, etoposide, cisplatin, and melphalan) and with two isomers of retinoic acid (RA): (9-cis and all-trans). Finally, we analyzed the distribution of the cell cycle, the induction of apoptosis, and the expression levels of p53, p21, and Bcl-2 in those two cell lines. P14ARF did not present promoter methylation, homozygous deletions, and protein expression in any of the 10 neuroblastoma cell lines. One TP53 point mutation was detected in the SK-N-FI cell line. MYCN amplification was frequent, while most cell lines did not present MDM2 amplification. Treatment of SK-N-FI and SK-N-Be(2) cells with doxorubicin, etoposide, cisplatin, and melphalan increased apoptosis and blocked the cycle in G2/M, while retinoic acid isomers induced apoptosis and decreased the percentage of cells in S phase in TP53 mutated SK-N-FI cells, but not in TP53 wild-type SK-N-Be(2) cells. Treatment with cisplatin, melphalan, or 9-cis RA decreased p53 expression levels in SK-N-FI cells but not in SK-N-Be (2). The expression of p21 was not modified in either of the two cell lines. Bcl-2 levels were reduced only in SK-N-FI cells after treatment with cisplatin. However, treatments with doxorubicin, etoposide, or 9-cis-RA did not modify the levels of this protein in either of the two cell lines. In conclusion, TP53 mutated SK-N-FI cells respond better to the retinoic isomers than TP53 wild-type SK-N-Be(2) cells. Although these are in vitro results, it seems that deciphering the molecular alterations of the p53/MDM2/p14ARF signaling pathway prior to treating patients of neuroblastoma might be useful for standardizing therapies with the aim of improving survival.

p53-Induced Autophagy Regulates Chemotherapy and Radiotherapy Resistance in Multidrug Resistance Cancer Cells

Background

Multidrug resistance (MDR), a major problem in oncology therapy, limits the effectiveness of anticancer drugs. Although p53 functions as a tumor suppressor, the associations between p53 status, autophagy, and MDR are complicated and conditional.

Method

 In this report, p53-null human ovarian cancer cell line SKOV3 and its MDR phenotype SKVCR and human leukemia cell line CEM and its MDR phenotype CEM-VLB) (p53 mutant cell line) were used.

Results

 Compared to parental SKOV3, the mRNA and protein levels of MAPLC3-II and Beclin1 were higher in SKVCR cells. The inhibition of autophagy by 3-MA significantly sensitized SKVCR to VCR. Conversely, in drug-resistant leukemic cells CEM-VLB, the expressions of Beclin1 and MAPLC3-II were lower than CEM. CEM and CEM-VLB cells were treated with VLB .01 or 0.5 μg/mL, respectively, and the expression of p53 and autophagy up-regulated after VLB (.01 μg/mL) treatment in CEM cells. The percentage of S-phase and G2/M phase cells up-regulated significantly by .01 μg/mL VLB in CEM, which may relate to the status of p53 of CEM cells. A combination of radiation with 3-MA significantly increased apoptosis in CEM-VLB cells.

Conclusion

 Our discovery found that p53 is an important regulator controlling the balance between autophagy and MDR, as a potential drug target for ovarian cancer and leukemia.

A-24, a steroidal saponin from Allium chinense, induced apoptosis, autophagy and migration inhibition in p53 wild-type and p53-deficient gastric cancer cells

Allium chinense is a vegetable with nutrition and unique flavor, and it is used as traditional Chinese medicine. We previously reported that the active compound A-24 induces apoptosis and autophagy in p53 wild-type gastric cancer cells through the PI3K/Akt/mTOR pathway. Our present work indicates that A-24 also has a significant proliferation inhibition effect on p53-deficient KATO-III cells, and the p53 status did not affect A-24 induced migration inhibition, but negatively controlled the occurrence of autophagy. We also found that the accumulation of reactive oxygen species (ROS) mediated A-24 induced apoptosis is p53-independent. Besides, p-Akt was not downregulated by A-24 in p53-deficient gastric cancer cells. Taken together, our results indicate that A-24 induced apoptosis and autophagy via the ROS-PI3K/Akt/mTOR pathway in p53 wild-type gastric cancer cells and through the ROS-mTOR pathway in p53-deficient gastric cancer cells. Our study recommended A-24 as a promising future phytotherapeutic candidate for gastric cancer treatment.

Mutations of p53 associated with pancreatic cancer and therapeutic implications

Pancreatic adenocarcinoma is a malignancy with rising incidence and grim prognosis. Despite improvements in therapeutics for treating metastatic pancreatic cancer, this disease is invariably fatal with survival time less than a few years. New molecular understanding of the pathogenesis of pancreatic adenocarcinoma based on efforts led by The Cancer Genome Atlas and other groups has elucidated the landscape of this disease and started to produce therapeutic results, leading to the first introduction of targeted therapies for subsets of pancreatic cancers bearing specific molecular lesions such as BRCA mutations. These efforts have highlighted that subsets of pancreatic cancers are particularly sensitive to chemotherapy. The most common molecular lesions in pancreatic adenocarcinomas are mutations in an oncogene KRAS and the TP53 gene that encodes for tumor suppressor protein p53. This paper will review the landscape of pancreatic cancers, focusing on mutations of p53, a major tumor suppressor protein, in pancreatic cancers and possible therapeutic repercussions.

The Crosstalk Between Long Non-Coding RNAs and Various Types of Death in Cancer Cells

With the increasing aging population, cancer has become one of the leading causes of death worldwide, and the number of cancer cases and deaths is only anticipated to grow further. Long non-coding RNAs (lncRNAs), which are closely associated with the expression level of downstream genes and various types of bioactivity, are regarded as one of the key regulators of cancer cell proliferation and death. Cell death, including apoptosis, necrosis, autophagy, pyroptosis, and ferroptosis, plays a vital role in the progression of cancer. A better understanding of the regulatory relationships between lncRNAs and these various types of cancer cell death is therefore urgently required. The occurrence and development of tumors can be controlled by increasing or decreasing the expression of lncRNAs, a method which confers broad prospects for cancer treatment. Therefore, it is urgent for us to understand the influence of lncRNAs on the development of different modes of tumor death, and to evaluate whether lncRNAs have the potential to be used as biological targets for inducing cell death and predicting prognosis and recurrence of chemotherapy. The purpose of this review is to provide an overview of the various forms of cancer cell death, including apoptosis, necrosis, autophagy, pyroptosis, and ferroptosis, and to describe the mechanisms of different types of cancer cell death that are regulated by lncRNAs in order to explore potential targets for cancer therapy.

Role of Dietary Antioxidants in p53-Mediated Cancer Chemoprevention and Tumor Suppression

Cancer arises through a complex interplay between genetic, behavioral, metabolic, and environmental factors that combined trigger cellular changes that over time promote malignancy. In terms of cancer prevention, behavioral interventions such as diet can promote genetic programs that may facilitate tumor suppression; and one of the key tumor suppressors responsible for initiating such programs is p53. The p53 protein is activated by various cellular events such as DNA damage, hypoxia, heat shock, and overexpression of oncogenes. Due to its role in cell fate decisions after DNA damage, regulatory pathways controlled by p53 help to maintain genome stability and thus “guard the genome” against mutations that cause cancer. Dietary intake of flavonoids, a C₁₅ group of polyphenols, is known to inhibit cancer progression and assist DNA repair through p53-mediated mechanisms in human cells via their antioxidant activities. For example, quercetin arrests human cervical cancer cell growth by blocking the G₂/M phase cell cycle and inducing mitochondrial apoptosis through a p53-dependent mechanism. Other polyphenols such as resveratrol upregulate p53 expression in several cancer cell lines by promoting p53 stability, which in colon cancer cells results in the activation of p53-mediated apoptosis. Finally, among vitamins, folic acid seems to play an important role in the chemoprevention of gastric carcinogenesis by enhancing gastric epithelial apoptosis in patients with premalignant lesions by significantly increased expression of p53. In this review, we discuss the role of these and other dietary antioxidants in p53-mediated cell signaling in relation to cancer chemoprevention and tumor suppression in normal and cancer cells.

The Multifaceted Functions of Autophagy in Breast Cancer Development and Treatment

Macroautophagy (herein referred to as autophagy) is a complex catabolic process characterized by the formation of double-membrane vesicles called autophagosomes. During this process, autophagosomes engulf and deliver their intracellular content to lysosomes, where they are degraded by hydrolytic enzymes. Thereby, autophagy provides energy and building blocks to maintain cellular homeostasis and represents a dynamic recycling mechanism. Importantly, the clearance of damaged organelles and aggregated molecules by autophagy in normal cells contributes to cancer prevention. Therefore, the dysfunction of autophagy has a major impact on the cell fate and can contribute to tumorigenesis. Breast cancer is the most common cancer in women and has the highest mortality rate among all cancers in women worldwide. Breast cancer patients often have a good short-term prognosis, but long-term survivors often experience aggressive recurrence. This phenomenon might be explained by the high heterogeneity of breast cancer tumors rendering mammary tumors difficult to target. This review focuses on the mechanisms of autophagy during breast carcinogenesis and sheds light on the role of autophagy in the traits of aggressive breast cancer cells such as migration, invasion, and therapeutic resistance.

Autophagic Markers in Chordomas: Immunohistochemical Analysis and Comparison with the Immune Microenvironment of Chordoma Tissues

Simple Summary

In contrast to normal notochords, autophagic factors are often present in chordomas. Furthermore, PD-L1+ immune cells also express LC3B, suggesting the need for further investigations between autophagy and the immune microenvironment.

Abstract

Chordomas are notably resistant to chemotherapy. One of the cytoprotective mechanisms implicated in chemoresistance is autophagy. There are indirect data that autophagy could be implicated in chordomas, but its presence has not been studied in chordoma tissues. Sixty-one (61) chordomas were immunohistochemically studied for autophagic markers and their expression was compared with the expression in notochords, clinicopathological data, as well as the tumor immune microenvironment. All chordomas strongly and diffusely expressed cytoplasmic p62 (sequestosome 1, SQSTM1/p62), whereas 16 (26.2%) tumors also showed nuclear p62 expression. LC3B (Microtubule-associated protein 1A/1B-light chain 3B) tumor cell expression was found in 44 (72.1%) tumors. Autophagy-related 16‑like 1 (ATG16L1) was also expressed by most tumors. All tumors expressed mannose-6-phosphate/insulin-like growth factor 2 receptor (M6PR/IGF2R). LC3B tumor cell expression was negatively associated with tumor size, while no other parameters, such as age, sex, localization, or survival, were associated with the immunohistochemical factors studied. LC3B immune cell expression showed a significant positive association with programmed death-ligand 1 (PD-L1)+ immune cells and with a higher vascular density. ATG16L1 expression was also positively associated with higher vascular density. Notochords (n = 5) showed different immunostaining with a very weak LC3B and M6PR expression, and no p62 expression. In contrast to normal notochords, autophagic factors such as LC3B and ATG16L1 are often present in chordomas, associated with a strong and diffuse expression of p62, suggesting a blocked autophagic flow. Furthermore, PD-L1+ immune cells also express LC3B, suggesting the need for further investigations between autophagy and the immune microenvironment.