GFRA1 promotes cisplatin-induced chemoresistance in osteosarcoma by inducing autophagy

Autophagy in cancer development, immune evasion, and drug resistance

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

The contribution of the novel CLTC-VMP1 fusion gene to autophagy regulation and energy metabolism in cisplatin-resistant osteosarcoma

Osteosarcoma (OS) is a highly malignant tumor, and chemotherapy resistance is a major challenge in the treatment of this disease. This study aims to explore the role of the CLTC-VMP1 gene fusion in the mechanism of chemotherapy resistance in OS and investigate its molecular mechanisms in mediating energy metabolism reprogramming by regulating autophagy and apoptosis balance. Using single-cell transcriptome analysis, the heterogeneity of OS cells and their correlation with resistance to platinum drugs were revealed. Cisplatin-resistant cell lines were established in human OS cell lines for subsequent experiments. Based on transcriptomic analysis, the importance of VMP1 in chemotherapy resistance was confirmed. Lentiviral vectors overexpressing or interfering with VMP1 were used, and it was observed that inhibiting VMP1 could reverse cisplatin resistance, promote cell apoptosis, and inhibit autophagy, and mitochondrial respiration and glycolysis. Furthermore, the presence of CLTC-VMP1 gene fusion was validated, and its ability to regulate autophagy and apoptosis balance, promote mitochondrial respiration, and glycolysis was demonstrated. Mouse model experiments further confirmed the promoting effect of CLTC-VMP1 on tumor growth and chemotherapy resistance. In summary, the CLTC-VMP1 gene fusion mediates energy metabolism reprogramming by regulating autophagy and apoptosis balance, which promotes chemotherapy resistance in OS.NEW & NOTEWORTHY This study identifies the CLTC-VMP1 gene fusion as a key driver of chemotherapy resistance in osteosarcoma by regulating autophagy and reprogramming cellular energy metabolism. Through single-cell transcriptomics, the research reveals the heterogeneity of tumor cells and the role of VMP1 in promoting resistance to cisplatin. The findings suggest that targeting the CLTC-VMP1 fusion gene may offer new therapeutic strategies to overcome chemotherapy resistance in osteosarcoma.

Salidroside overcomes cisplatin resistance in ovarian cancer via the inhibition of CRNDE-mediated autophagy

Cisplatin (DDP) resistance significantly affects the survival rate of patients with ovarian cancer (OC). Autophagy is recognized as a common cause of resistance to DDP. This study aimed to investigate the impact of salidroside on OC progression and explore its potential regulatory effects on DDP resistance and autophagy. A DDP-resistant A2780 (A2780/DDP) cell line was induced by exposure to increasing DDP concentrations. The protein levels of autophagy proteins (p62, Beclin-1, ATG5, and LC3 II/LC3 I), apoptosis proteins (cleaved caspase-3 and cleaved caspase-9), and PI3K/AKT/mTOR pathway were determined by western blotting. Autophagic vacuoles in cells were observed with LC3 dyeing with confocal fluorescent microscopy. Cell viability and apoptosis were evaluated by cell counting kit-8 assays and flow cytometry. RT-qPCR was conducted to measure the relative levels of various lncRNAs in A2780 or A2780/DDP cells. A xenograft model was established by subcutaneous injection of 1 × 107 A2780 cells into the posterior flank of nude mice. Tumor size and weight were recorded. The expression of Ki67, cleaved caspase-3 and LC3 in tumor tissues was assessed by immunohistochemistry staining. The biodistribution of DDP in organs and blood of normal nude mice and tumors of tumor-bearing mice was detected using the ICP-MS. Hematoxylin-eosin staining was used to assess the histopathological changes of kidney, liver, and spleen sections. For in vitro analysis, autophagy was enhanced in DDP-resistant A2780 cells. Additionally, salidroside inhibits DDP resistance to A2780 cells via autophagy inhibition. Mechanistically, salidroside downregulated CRNDE in DDP-resistant A2780 cells. CRNDE knockdown inhibited autophagy, while CRNDE overexpression reversed the protective effects of salidroside. Additionally, salidroside activated the PI3K/AKT/mTOR pathway in DDP-resistant A2780 cells, and inhibition of PI3K reversed the effect of salidroside on inhibiting autophagy and apoptosis of A2780/DDP cells. For in vivo analysis, salidroside inhibited tumor growth, autophagy, and nephrotoxicity of DDP. Additionally, salidroside downregulated CRNDE and activated PI3K/AKT/mTOR signaling in vivo. Salidroside prevents autophagy-mediated DDP resistance in OC by downregulating lncRNA CRNDE and activating the PI3K/AKT/mTOR pathway.

Trends and future directions of autophagy in osteosarcoma: A bibliometric analysis

Background

Osteosarcoma, a highly malignant skeletal tumor, primarily affects children and adolescents. Autophagy plays a crucial role in osteosarcoma pathophysiology. This study utilizes bibliometric analysis to evaluate current research on autophagy in osteosarcoma and forecast future directions.

Methods

We conducted a comprehensive search of publications in the Web of Science Core Collection database from January 1, 2008, to March 15, 2024. Tools like VOSviewer, CiteSpace, R software, Excel, and Scimago were used for analysis and visualization.

Results

Publications increased steadily over 17 years, indicating rising interest. Zhang Yuan was the most influential author, with Shanghai Jiao Tong University leading. Cell Death & Disease was the top journal. "HMGB1 Promotes Drug Resistance in Osteosarcoma" was the most cited paper. Co-cited articles focused on drug resistance, therapeutic targets, autophagy in cancer, and genomic impacts on immunotherapy. Keywords highlighted invasion, migration, cell death, and breast cancer as research hotspots. Future studies will likely focus on therapeutic innovations and integrated management strategies.

Conclusion

This bibliometric analysis offers an overview of current knowledge and emerging trends in autophagy and osteosarcoma, emphasizing key areas like invasion, migration, and cell death. It serves as a valuable resource for researchers developing novel therapies for osteosarcoma.

PFKFB3 deprivation attenuates the cisplatin resistance via blocking its autophagic elimination in colorectal cancer cells

Introduction

6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase isoform 3 (PFKFB3) is highly expressed in several cancers and plays important roles during the whole pathological process of cancer. It is also involved in chemoresistance, while the intrinsic mechanism needs to be further revealed.

Methods

The different responses to cisplatin (DDP) between wild type (WT) and DDP-resistant (DDR) colorectal cancer (CRC) cells were analyzed by several assays. Coumarin conjugated DDP (CP-DDP) was utilized to trace the distribution of DDP. Pharmacological and genetic methods were used to deprive autophagy and PFKFB3, and the effects were investigated. The mouse xenograft model was performed to confirm the effect of the PFKFB3 inhibitor on reversing DDP resistance.

Results

DDR cells showed a lower capacity for apoptosis upon DDP treatment, but exhibited higher levels of autophagy and PFKFB3. CP-DDP partly co-localized with LC3, and its content lessened faster in DDR cells. Deprivation of both autophagy and PFKFB3 attenuated CP-DDP elimination, and reversed the DDP resistance. Moreover, PFKFB3 inhibition reduced DDP-induced autophagy. PFKFB3 inhibitor in combination with DDP led to a remarkable reduction in tumor growth in vivo.

Discussions

Inhibition of PFKFB3 reduced the autophagy induced by DDP, and therefore extended the retention time of CP-DDP. Meanwhile, PFKFB3 deprivation reversed the DDP resistance and made it a potent therapeutic target for CRC.

WTAP-mediated m6A modification of circ_0032463 promotes osteosarcoma progression by sponging miR-145-5p and regulating GFRA1 expression

Osteosarcoma (OS) is the most frequent bone malignancy in humans. Previous evidence suggest that circ_0032463 is an oncogenic circular RNA (circRNA) in various cancers, including OS. However, the molecular mechanism of circ_0032463 involved in OS is still unclear. Circ_0032463, microRNA-145-5p (miR-145-5p), GDNF receptor alpha 1 (GFRA1), and Wilms tumor 1-associated protein (WTAP) levels were determined using real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation, apoptosis, migration, invasion, and angiogenesis were analyzed using 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, transwell, and tube formation assays. Western blot analysis was performed to measure matrix metalloproteinase 2 (MMP2), MMP9, GFRA1, and WTAP protein levels. Binding between miR-145-5p and circ_0032463 or GFRA1 was confirmed using a dual-luciferase reporter and pull-down assay. The biological role of circ_0032463 on OS cell growth was also analyzed using a xenograft tumor model in vivo. Methylated RNA immunoprecipitation assay validated the interaction between WTAP and circ_0032463. Circ_0032463, GFRA1, and WTAP levels were increased, and miR-145-5p was decreased in OS tissues and cells. Circ_0032463 deficiency might hinder OS cell proliferation, migration, invasion, angiogenesis, and promote apoptosis in vitro. Mechanically, circ_0032463 worked as a miR-145-5p sponge to increase GFRA1 expression. Repression of circ_0032463 knockdown on tumor cell growth was proved in vivo. Besides, N6-methyladenosine (m6A) modification facilitates the biogenesis of circ_0032463. Taken together, m6A-mediated biogenesis of circ_0032463 facilitates OS cell malignant biological behavior partly via regulating the miR-145-5p/GFRA1 axis, suggesting a promising molecular marker for OS treatment.

Xenografting Human Musculoskeletal Sarcomas in Mice, Chick Embryo, and Zebrafish: How to Boost Translational Research

Musculoskeletal sarcomas pose major challenges to researchers and clinicians due to their rarity and heterogeneity. Xenografting human cells or tumor fragments in rodents is a mainstay for the generation of cancer models and for the preclinical trial of novel drugs. Lately, though, technical, intrinsic and ethical concerns together with stricter regulations have significantly curbed the employment of murine patient-derived xenografts (mPDX). In alternatives to murine PDXs, researchers have focused on embryonal systems such as chorioallantoic membrane (CAM) and zebrafish embryos. These systems are time- and cost-effective hosts for tumor fragments and near-patient cells. The CAM of the chick embryo represents a unique vascularized environment to host xenografts with high engraftment rates, allowing for ease of visualization and molecular detection of metastatic cells. Thanks to the transparency of the larvae, zebrafish allow for the tracking of tumor development and metastatization, enabling high-throughput drug screening. This review will focus on xenograft models of musculoskeletal sarcomas to highlight the intrinsic and technically distinctive features of the different hosts, and how they can be exploited to elucidate biological mechanisms beneath the different phases of the tumor's natural history and in drug development. Ultimately, the review suggests the combination of different models as an advantageous approach to boost basic and translational research.

METTL3-mediated m6A modification of LINC00520 confers glycolysis and chemoresistance in osteosarcoma via suppressing ubiquitination of ENO1

Chemoresistance remains the main obstacle limiting the treatment of osteosarcoma, seriously affecting the prognosis of adolescent patients with osteosarcoma. Recently, long non-coding RNAs (lncRNAs) were reported to be involved in chemoresistance, while the mechanisms of lncRNAs underlying osteosarcoma resistance to chemotherapy remain elusive. Here, LINC00520 was identified as a novel cisplatin resistance-related lncRNA in osteosarcoma, and its high expression was associated with poor prognosis of osteosarcoma patients. Functionally, LINC00520 could potentiate osteosarcoma resistance to cisplatin in vitro and in vivo. Mechanistically, LINC00520 bound to ENO1 and upregulated ENO1 protein expression by blocking FBXW7-mediated ENO1 ubiquitination and proteasomal degradation, thereby promoting glycolysis and ultimately inducing cisplatin resistance in osteosarcoma. Furthermore, METTL3 could stabilize and upregulate LINC00520 in an m6A-YTHDF2-dependent manner in osteosarcoma. This study proposes a novel lncRNA-driven mechanism for cisplatin resistance in osteosarcoma, and offers a promising therapeutic strategy for reversing chemoresistance in osteosarcoma by targeting the METTL3/LINC00520/ENO1/glycolysis axis.

GDNF-induced phosphorylation of MUC21 promotes pancreatic cancer perineural invasion and metastasis by activating RAC2 GTPase

Perineural invasion (PNI) is an adverse prognostic feature of pancreatic ductal adenocarcinoma (PDAC). However, the understanding of the interactions between tumors and neural signaling within the tumor microenvironment is limited. In the present study, we found that MUC21 servers as an independent risk factor for poor prognosis in PDAC. Furthermore, we demonstrated that MUC21 promoted the metastasis and PNI of PDAC cells by activating JNK and inducing epithelial-mesenchymal transition (EMT). Mechanistically, glial cell-derived neurotrophic factor, secreted by Schwann cells, phosphorylates the intracellular domain S543 of MUC21 via CDK1 in PDAC cells, facilitating the interaction between MUC21 and RAC2. This interaction leads to membrane anchoring and activation of RAC2, which in turn activates the JNK/ZEB1/EMT axis, ultimately enhancing the metastasis and PNI of PDAC cells. Our results present a novel mechanism of PNI, suggesting that MUC21 is a potential prognostic marker and therapeutic target for PDAC.

LncRNAs as potential prognosis/diagnosis markers and factors driving drug resistance of osteosarcoma, a review

Osteosarcoma is a common malignancy that often occurs in children, teenagers and young adults. Although the treatment strategy has improved, the results are still poor for most patients with metastatic or recurrent osteosarcomas. Therefore, it is necessary to identify new and effective prognostic biomarkers and therapeutic targets for diseases. Human genomes contain lncRNAs, transcripts with limited or insufficient capacity to encode proteins. They have been implicated in tumorigenesis, particularly regarding the onset, advancement, resistance to treatment, recurrence and remote dissemination of malignancies. Aberrant lncRNA expression in osteosarcomas has been reported by numerous researchers; lncRNAs have the potential to exhibit either oncogenic or tumor-suppressing behaviors and thus, to govern the advancement of this skeletal cancer. They are suspected to influence osteosarcoma cell growth, replication, invasion, migration, remote dissemination and programmed cell death. Additionally, they have been recognized as clinical markers, and may participate in the development of multidrug resistance. Therefore, the study of lncRNAs in the growth, metastasis, treatment and prognosis of osteosarcoma is very important for the active prevention and treatment of osteosarcoma. Consequently, this work reviews the functions of lncRNAs.

Autophagy in cancer immunotherapy: Perspective on immune evasion and cell death interactions

Both the innate and adaptive immune systems work together to produce immunity. Cancer immunotherapy is a novel approach to tumor suppression that has arisen in response to the ineffectiveness of traditional treatments like radiation and chemotherapy. On the other hand, immune evasion can diminish immunotherapy's efficacy. There has been a lot of focus in recent years on autophagy and other underlying mechanisms that impact the possibility of cancer immunotherapy. The primary feature of autophagy is the synthesis of autophagosomes, which engulf cytoplasmic components and destroy them by lysosomal degradation. The planned cell death mechanism known as autophagy can have opposite effects on carcinogenesis, either increasing or decreasing it. It is autophagy's job to maintain the balance and proper functioning of immune cells like B cells, T cells, and others. In addition, autophagy controls whether macrophages adopt the immunomodulatory M1 or M2 phenotype. The ability of autophagy to control the innate and adaptive immune systems is noteworthy. Interleukins and chemokines are immunological checkpoint chemicals that autophagy regulates. Reducing antigen presentation to induce immunological tolerance is another mechanism by which autophagy promotes cancer survival. Therefore, targeting autophagy is of importance for enhancing potential of cancer immunotherapy.

The role of programmed cell death in osteosarcoma: From pathogenesis to therapy

Osteosarcoma (OS) is a prevalent bone solid malignancy that primarily affects adolescents, particularly boys aged 14-19. This aggressive form of cancer often leads to deadly lung cancer due to its high migration ability. Experimental evidence suggests that programmed cell death (PCD) plays a crucial role in the development of osteosarcoma. Various forms of PCD, including apoptosis, ferroptosis, autophagy, necroptosis, and pyroptosis, contribute significantly to the progression of osteosarcoma. Additionally, different signaling pathways such as STAT3/c-Myc signal pathway, JNK signl pathway, PI3k/AKT/mTOR signal pathway, WNT/β-catenin signal pathway, and RhoA signal pathway can influence the development of osteosarcoma by regulating PCD in osteosarcoma cell. Therefore, targeting PCD and the associated signaling pathways could offer a promising therapeutic approach for treating osteosarcoma.

Harnessing ferroptosis for enhanced sarcoma treatment: mechanisms, progress and prospects

Sarcoma is a malignant tumor that originates from mesenchymal tissue. The common treatment for sarcoma is surgery supplemented with radiotherapy and chemotherapy. However, patients have a 5-year survival rate of only approximately 60%, and sarcoma cells are highly resistant to chemotherapy. Ferroptosis is an iron-dependent nonapoptotic type of regulated programmed cell death that is closely related to the pathophysiological processes underlying tumorigenesis, neurological diseases and other conditions. Moreover, ferroptosis is mediated via multiple regulatory pathways that may be targets for disease therapy. Recent studies have shown that the induction of ferroptosis is an effective way to kill sarcoma cells and reduce their resistance to chemotherapeutic drugs. Moreover, ferroptosis-related genes are related to the immune system, and their expression can be used to predict sarcoma prognosis. In this review, we describe the molecular mechanism underlying ferroptosis in detail, systematically summarize recent research progress with respect to ferroptosis application as a sarcoma treatment in various contexts, and point out gaps in the theoretical research on ferroptosis, challenges to its clinical application, potential resolutions of these challenges to promote ferroptosis as an efficient, reliable and novel method of clinical sarcoma treatment.

Autophagy-modulating biomembrane nanostructures: A robust anticancer weapon by modulating the inner and outer cancer environment

Recently, biomembrane nanostructures, such as liposomes, cell membrane-coated nanostructures, and exosomes, have demonstrated promising anticancer therapeutic effects. These nanostructures possess remarkable biocompatibility, multifunctionality, and low toxicity. However, their therapeutic efficacy is impeded by chemoresistance and radiotherapy resistance, which are closely associated with autophagy. Modulating autophagy could enhance the therapeutic sensitivity and effectiveness of these biomembrane nanostructures by influencing the immune system and the cancer microenvironment. For instance, autophagy can regulate the immunogenic cell death of cancer cells, antigen presentation of dendritic cells, and macrophage polarization, thereby activating the inflammatory response in the cancer microenvironment. Furthermore, combining autophagy-regulating drugs or genes with biomembrane nanostructures can exploit the targeting and long-term circulation properties of these nanostructures, leading to increased drug accumulation in cancer cells. This review explores the role of autophagy in carcinogenesis, cancer progression, metastasis, cancer immune responses, and resistance to treatment. Additionally, it highlights recent research advancements in the synergistic anticancer effects achieved through autophagy regulation by biomembrane nanostructures. The review also discusses the prospects and challenges associated with the future clinical translation of these innovative treatment strategies. In summary, these findings provide valuable insights into autophagy, autophagy-modulating biomembrane-based nanostructures, and the underlying molecular mechanisms, thereby facilitating the development of promising cancer therapeutics.

HMGA2 promotes nasopharyngeal carcinoma progression and is associated with tumor resistance and poor prognosis

Nasopharyngeal carcinoma (NPC), as one of the most prevalent malignancies in the head and neck region, still lacks a complete understanding of its pathogenesis. Presently, radiotherapy, concurrent chemoradiotherapy, and targeted therapy stand as the primary modalities for treating NPC. With advancements in medicine, the cure rates for nasopharyngeal carcinoma have been steadily increasing. Nevertheless, recurrence and metastasis persist as the primary reasons for treatment failure. Consequently, a profound exploration of the molecular mechanisms underlying the occurrence and progression of nasopharyngeal carcinoma, along with the exploration of corresponding therapeutic approaches, becomes particularly imperative in the quest for comprehensive solutions to combat this disease. High mobility group AT-hook 2 (HMGA2) is a pivotal protein capable of altering chromatin structure, regulating gene expression, and influencing transcriptional activity. In the realm of cancer research, HMGA2 exhibits widespread dysregulation, playing a crucial role in nearly all malignant tumors. It is implicated in various tumorigenic processes, including cell cycle regulation, cell proliferation, epithelial-mesenchymal transition, angiogenesis, tumor invasion, metastasis, and drug resistance. Additionally, HMGA2 serves as a molecular marker and an independent prognostic factor in certain malignancies. Recent studies have increasingly unveiled the critical role of HMGA2 in nasopharyngeal carcinoma (NPC), particularly in promoting malignant progression, correlating with tumor resistance, and serving as an independent adverse prognostic factor. This review focuses on elucidating the oncogenic role of HMGA2 in NPC, suggesting its potential association with chemotherapy resistance in NPC, and proposing its candidacy as an independent factor in nasopharyngeal carcinoma prognosis assessment.

Versatile function of AMPK signaling in osteosarcoma: An old player with new emerging carcinogenic functions

AMP-activated protein kinase (AMPK) signaling has a versatile role in Osteosarcoma (OS), an aggressive bone malignancy with a poor prognosis, particularly in cases that have metastasized or recurred. This review explores the regulatory mechanisms, functional roles, and therapeutic applications of AMPK signaling in OS. It focuses on the molecular activation of AMPK and its interactions with cellular processes like proliferation, apoptosis, and metabolism. The uncertain role of AMPK in cancer is also discussed, highlighting its potential as both a tumor suppressor and a contributor to carcinogenesis. The therapeutic potential of targeting AMPK signaling in OS treatment is examined, including direct and indirect activators like metformin, A-769662, resveratrol, and salicylate. Further research is needed to determine dosing, toxicities, and molecular mechanisms responsible for the anti-osteosarcoma effects of these compounds. This review underscores the complex involvement of AMPK signaling in OS and emphasizes the need for a comprehensive understanding of its molecular mechanisms. By elucidating the role of AMPK in OS, the aim is to pave the way for innovative therapeutic approaches that target this pathway, ultimately improving the prognosis and quality of life for OS patients.

Autophagy Modulation as a Potential Therapeutic Strategy in Osteosarcoma: Current Insights and Future Perspectives

Autophagy, the process that enables the recycling and degradation of cellular components, is essential for homeostasis, which occurs in response to various types of stress. Autophagy plays an important role in the genesis and evolution of osteosarcoma (OS). The conventional treatment of OS has limitations and is not always effective at controlling the disease. Therefore, numerous researchers have analyzed how controlling autophagy could be used as a treatment or strategy to reverse resistance to therapy in OS. They highlight how the inhibition of autophagy improves the efficacy of chemotherapeutic treatments and how the promotion of autophagy could prove positive in OS therapy. The modulation of autophagy can also be directed against OS stem cells, improving treatment efficacy and preventing cancer recurrence. Despite promising findings, future studies are needed to elucidate the molecular mechanisms of autophagy and its relationship to OS, as well as the mechanisms underlying the functioning of autophagic modulators. Careful evaluation is required as autophagy modulation may have adverse effects on normal cells, and the optimization of autophagic modulators for use as drugs in OS is imperative.

Unveiling the Neural Environment in Cancer: Exploring the Role of Neural Circuit Players and Potential Therapeutic Strategies

The regulation of the immune environment within the tumor microenvironment has provided new opportunities for cancer treatment. However, an important microenvironment surrounding cancer that is often overlooked despite its significance in cancer progression is the neural environment surrounding the tumor. The release of neurotrophic factors from cancer cells is implicated in cancer growth and metastasis by facilitating the infiltration of nerve cells into the tumor microenvironment. This nerve-tumor interplay can elicit cancer cell proliferation, migration, and invasion in response to neurotransmitters. Moreover, it is possible that cancer cells could establish a network resembling that of neurons, allowing them to communicate with one another through neurotransmitters. The expression levels of players in the neural circuits of cancers could serve as potential biomarkers for cancer aggressiveness. Notably, the upregulation of certain players in the neural circuit has been linked to poor prognosis in specific cancer types such as breast cancer, pancreatic cancer, basal cell carcinoma, and stomach cancer. Targeting these players with inhibitors holds great potential for reducing the morbidity and mortality of these carcinomas. However, the efficacy of anti-neurogenic agents in cancer therapy remains underexplored, and further research is necessary to evaluate their effectiveness as a novel approach for cancer treatment. This review summarizes the current knowledge on the role of players in the neural circuits of cancers and the potential of anti-neurogenic agents for cancer therapy.

Molecular biology of microRNA-342 during tumor progression and invasion

Cancer is considered as one of the main causes of human deaths and health challenges in the world. Various factors are involved in the high death rate of cancer patients, including late diagnosis and drug resistance that result in treatment failure and tumor recurrence. Invasive diagnostic methods are one of the main reasons of late tumor detection in cancer patients. Therefore, it is necessary to investigate the molecular tumor biology to introduce efficient non-invasive markers. MicroRNAs (miRNAs) are involved in regulation of the cellular mechanisms such as cell proliferation, apoptosis, and migration. MiRNAs deregulations have been also frequently shown in different tumor types. Here, we discussed the molecular mechanisms of miR-342 during tumor growth. MiR-342 mainly functions as a tumor suppressor by the regulation of transcription factors and signaling pathways such as WNT, PI3K/AKT, NF-kB, and MAPK. Therefore, miR-342 mimics can be used as a reliable therapeutic strategy to inhibit the tumor cells growth. The present review can also pave the way to introduce the miR-342 as a non-invasive diagnostic/prognostic marker in cancer patients.

circGFRA1: A circular RNA with important roles in human carcinogenesis

Circular RNAs (circRNAs) are a type of covalently closed RNA molecules, which are mainly formed by back splicing of a precursor mRNA upstream exon into a downstream exon. Abnormally expressed circRNAs can modulate gene transcription by indirectly interacting with microRNAs (miRNAs). According to the current studies, circGFRA1 has been suggested to be upregulated in various cancers. circGFRA1 (hsa_circ_005239) is a type of cancer-related circRNA, which is predicted to be originated from the GFRA1 on chromosome 10. circGFRA1 can act as a sponge for several miRNAs, including miR-34a, miR-1228, miR-361-5p, miR-149, miR-498, miR-188-3p, miR-3064-5p, miR-449a. Additionally, it can regulate signaling pathways such as TGF-β and PI3K/ AKT. circGFRA1 upregulation has been correlated with patients' poor overall survival in diverse cancers. In the present review, we have summarized the oncogenic effect of circGFRA1 in various cancers according to the adopted criteria from in vitro, in vivo, and clinical research. Moreover, functional enrichment analysis was performed on the circGFRA1 host gene and its protein interaction network to detect gene ontology and related pathways.

Autophagy Regulators in Cancer

Autophagy plays a complex impact role in tumor initiation and development. It serves as a double-edged sword by supporting cell survival in certain situations while also triggering autophagic cell death in specific cellular contexts. Understanding the intricate functions and mechanisms of autophagy in tumors is crucial for guiding clinical approaches to cancer treatment. Recent studies highlight its significance in various aspects of cancer biology. Autophagy enables cancer cells to adapt to and survive unfavorable conditions by recycling cellular components. However, excessive or prolonged autophagy can lead to the self-destruction of cancer cells via a process known as autophagic cell death. Unraveling the molecular mechanisms underlying autophagy regulation in cancer is crucial for the development of targeted therapeutic interventions. In this review, we seek to present a comprehensive summary of current knowledge regarding autophagy, its impact on cancer cell survival and death, and the molecular mechanisms involved in the modulation of autophagy for cancer therapy.

ERRα contributes to HDAC6-induced chemoresistance of osteosarcoma cells

Chemotherapy resistance is an important problem for clinical therapy of osteosarcoma (OS). The potential effects of histone deacetylases (HDACs) on OS chemoresistance are studied. The expression of HDACs in OS cells resistance to doxorubicin (Dox) and cisplatin (CDDP) is checked. Among 11 members of HDACs, levels of HDAC6 are significantly upregulated in OS cells resistance to Dox and CDDP. Inhibition of HDAC6 via its specific inhibitor ACY1215 restores chemosensitivity of OS-resistant cells. Further, HDAC6 directly binds with estrogen-related receptors alpha (ERRα) to regulate its acetylation and protein stability. Inhibition of ERRα further strengthens ACY1215-increased chemosensitivity of OS-resistant cells. Mechanistically, K129 acetylation is the key residue for HDAC6-regulated protein levels of ERRα. Collectively, we find that ERRα contributes to HDAC6-induced chemoresistance of OS cells. Inhibition of HDAC6/ERRα axis might be a potential approach to overcome chemoresistance and improve therapy efficiency for OS treatment. 1. HDAC6 was significantly upregulated in Dox and CDDP resistant OS cells; 2. Inhibition of HDAC6 can restore chemosensitivity of OS cells; 3. HDAC6 binds with ERRα at K129 to decrease its acetylation and increase protein stability; 4. ERRα contributes to HDAC6-induced chemoresistance of OS cells.

MicroRNAs as the critical regulators of autophagy-mediated cisplatin response in tumor cells

Chemotherapy is one of the most common therapeutic methods in advanced and metastatic tumors. Cisplatin (CDDP) is considered as one of the main first-line chemotherapy drugs in solid tumors. However, there is a high rate of CDDP resistance in cancer patients. Multi-drug resistance (MDR) as one of the main therapeutic challenges in cancer patients is associated with various cellular processes such as drug efflux, DNA repair, and autophagy. Autophagy is a cellular mechanism that protects the tumor cells toward the chemotherapeutic drugs. Therefore, autophagy regulatory factors can increase or decrease the chemotherapy response in tumor cells. MicroRNAs (miRNAs) have a pivotal role in regulation of autophagy in normal and tumor cells. Therefore, in the present review, we discussed the role of miRNAs in CDDP response through the regulation of autophagy. It has been reported that miRNAs mainly increased the CDDP sensitivity in tumor cells by inhibition of autophagy. PI3K/AKT signaling pathway and autophagy-related genes (ATGs) were the main targets of miRNAs in the regulation of autophagy-mediated CDDP response in tumor cells. This review can be an effective step to introduce the miRNAs as efficient therapeutic options to increase autophagy-mediated CDDP sensitivity in tumor cells.

Pipeline for Characterizing Alternative Mechanisms (PCAM) based on bi-clustering to study colorectal cancer heterogeneity

The cells of colorectal cancer (CRC) in their microenvironment experience constant stress, leading to dysregulated activity in the tumor niche. As a result, cancer cells acquire alternative pathways in response to the changing microenvironment, posing significant challenges for the design of effective cancer treatment strategies. While computational studies on high-throughput omics data have advanced our understanding of CRC subtypes, characterizing the heterogeneity of this disease remains remarkably complex. Here, we present a novel computational Pipeline for Characterizing Alternative Mechanisms (PCAM) based on biclustering to gain a more detailed understanding of cancer heterogeneity. Our application of PCAM to large-scale CRC transcriptomics datasets suggests that PCAM can generate a wealth of information leading to new biological understanding and predictive markers of alternative mechanisms. Our key findings include: 1) A comprehensive collection of alternative pathways in CRC, associated with biological and clinical factors. 2) Full annotation of detected alternative mechanisms, including their enrichment in known pathways and associations with various clinical outcomes. 3) A mechanistic relationship between known clinical subtypes and outcomes on a consensus map, visualized by the presence of alternative mechanisms. 4) Several potential novel alternative drug resistance mechanisms for Oxaliplatin, 5-Fluorouracil, and FOLFOX, some of which were validated on independent datasets. We believe that gaining a deeper understanding of alternative mechanisms is a critical step towards characterizing the heterogeneity of CRC. The hypotheses generated by PCAM, along with the comprehensive collection of biologically and clinically associated alternative pathways in CRC, could provide valuable insights into the underlying mechanisms driving cancer progression and drug resistance, which could aid in the development of more effective cancer therapies and guide experimental design towards more targeted and personalized treatment strategies. The computational pipeline of PCAM is available in GitHub (https://github.com/changwn/BC-CRC).

Ebastine exerts antitumor activity and induces autophagy by activating AMPK/ULK1 signaling in an IPMK-dependent manner in osteosarcoma

Numerous studies have confirmed that in addition to interfering with the tumor inflammatory environment, anti-inflammatory agents can directly increase apoptosis and sensitivity to conventional therapies and decrease invasion and metastasis, making them useful candidates for cancer therapy. Here, we first used high-throughput screening and had screened one compound candidate, ebastine (a H1-histamine receptor antagonist), for osteosarcoma therapy. Cell viability assays, colony formation assays, wound healing assays, and Transwell assays demonstrated that ebastine elicited antitumor effects in osteosarcoma cells. In addition, ebastine treatment exerted obvious effects on cell cycle arrest, metastasis inhibition, apoptosis and autophagy induction both in vitro and in vivo. Mechanistically, we observed that ebastine treatment triggered proapoptotic autophagy by activating AMPK/ULK1 signaling in osteosarcoma cells. Treatment with the AMPK inhibitor dorsomorphin reversed ebastine-induced apoptosis and autophagy. More importantly, we found that IPMK interacted with AMPK and functioned as a positive regulator of AMPK protein in osteosarcoma cells. A rescue study showed that the induction of autophagy and activation of the AMPK/ULK1 signaling pathway by ebastine treatment were reversed by IPMK knockdown, indicating that the activity of ebastine was IPMK dependent. We provide experimental evidence demonstrating that ebastine has antitumor activity in osteosarcoma and promotes autophagy by activating the AMPK/ULK1 signaling pathway, which is IPMK dependent. Our results provide insight into the clinical application potential of ebastine, which may represent a new potential therapeutic candidate for the treatment of osteosarcoma.

Superenhancers activate the autophagy-related genes Beclin1 and LC3B to drive metastasis and drug resistance in osteosarcoma

Metastasis and drug resistance are the leading causes of poor prognosis in patients with osteosarcoma. Identifying the relevant factors that drive metastasis and drug resistance is the key to improving the therapeutic outcome of osteosarcoma. Here, we reported that autophagy was highly activated in metastatic osteosarcoma. We found increased autophagolysosomes in metastatic osteosarcoma cell lines by using electron microscopy, Western blot, and immunofluorescence experiments. We further examined the expression of the autophagy-related genes Beclin1 and LC3B in 82 patients through immunohistochemistry and found that Beclin1 and LC3B were highly related to unfavorable prognosis of osteosarcoma. Knockdown of Beclin1 and LC3B reduced invasion, metastasis, and proliferation in metastatic osteosarcoma cells. In vitro and in vivo studies also demonstrated that inhibiting by 3-MA inhibited cell growth and metastasis. Moreover, we demonstrated that autophagy-related genes were activated by SEs and that the inhibition of SEs by JQ-1 decreased the metastasis of osteosarcoma. Overall, our findings highlighted the association of autophagy with osteosarcoma progression and shed new light on autophagy-targeting therapy for osteosarcoma.

Receptor Tyrosine Kinase Inhibitors for the Treatment of Recurrent and Unresectable Bone Sarcomas

Bone sarcomas are a heterogeneous group of rare tumors with a predominance in the young population. Few options of systemic treatment are available once they become unresectable and resistant to conventional chemotherapy. A better knowledge of the key role that tyrosine kinase receptors (VEGFR, RET, MET, AXL, PDGFR, KIT, FGFR, IGF-1R) may play in the pathogenesis of these tumors has led to the development of multi-target inhibitors (TKIs) that are progressively being incorporated into our therapeutic arsenal. Osteosarcoma (OS) is the most frequent primary bone tumor and several TKIs have demonstrated clinical benefit in phase II clinical trials (cabozantinib, regorafenib, apatinib, sorafenib, and lenvatinib). Although the development of TKIs for other primary bone tumors is less advanced, preclinical data and early trials have begun to show their potential benefit in advanced Ewing sarcoma (ES) and rarer bone tumors (chondrosarcoma, chordoma, giant cell tumor of bone, and undifferentiated pleomorphic sarcoma). Previous reviews have mainly provided information on TKIs for OS and ES. We aim to summarize the existing knowledge regarding the use of TKIs in all bone sarcomas including the most recent studies as well as the potential synergistic effects of their combination with other systemic therapies.

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.

Identification of ATG7 as a Regulator of Proferroptosis and Oxidative Stress in Osteosarcoma

Background

Ferroptosis has gained significant attention from oncologists as a vital outcome of oxidative stress. The aim of this study was to develop a prognostic signature that was based on the ferroptosis-related genes (FRGs) for osteosarcoma patients and explore their specific role in osteosarcoma.

Methods

The training cohort dataset was extracted from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database. Different techniques like the univariate Cox regression, least absolute shrinkage and selection operator (LASSO) regression, multivariate Cox regression analyses, and the Kaplan-Meier (KM) survival analyses were utilized to develop a prognostic signature. Then, the intrinsic relationship between the developed gene signature and the infiltration levels of the immune cells was further investigated. An external validation dataset from the Gene Expression Omnibus (GEO) database was employed to assess the predictive ability of the developed gene signature. Subsequently, the specific function of potential FRG in affecting the oxidative stress reaction and ferroptosis of osteosarcoma cells was identified.

Results

A prognostic signature based on 5 FRGs (CBS, MUC1, ATG7, SOCS1, and PEBP1) was developed, and the patients were classified into the low- and high-risk groups (categories). High-risk patients displayed poor overall survival outcomes. The risk level was seen to be an independent risk factor for determining the prognosis of osteosarcoma patients (p < 0.001, hazard ratio: 7.457, 95% CI: 3.302-16.837). Additionally, the risk level was associated with immune function, which might affect the survival status of osteosarcoma patients. Moreover, the findings of the study indicated that the expression of ATG7 was related to the regulation of oxidative stress in osteosarcoma. Silencing the ATG7 gene promoted the proliferation and migration in osteosarcoma cells, suppressing the oxidative stress and ferroptosis process.

Conclusions

A novel FRG signature was developed in this study to predict the prognosis of osteosarcoma patients. The results indicated that ATG7 might regulate the process of oxidative stress and ferroptosis in osteosarcoma cells and could be used as a potential target to develop therapeutic strategies for treating osteosarcoma.

Targeting O-GlcNAcylation to overcome resistance to anti-cancer therapies

In cancer cells, metabolic reprogramming is associated with an alteration of the O-GlcNAcylation homeostasis. This post-translational modification (PTM) that attaches O-GlcNAc moiety to intracellular proteins is dynamically and finely regulated by the O-GlcNAc Transferase (OGT) and the O-GlcNAcase (OGA). It is now established that O-GlcNAcylation participates in many features of cancer cells including a high rate of cell growth, invasion, and metastasis but little is known about its impact on the response to therapies. The purpose of this review is to highlight the role of O-GlcNAc protein modification in cancer resistance to therapies. We summarize the current knowledge about the crosstalk between O-GlcNAcylation and molecular mechanisms underlying tumor sensitivity/resistance to targeted therapies, chemotherapies, immunotherapy, and radiotherapy. We also discuss potential benefits and strategies of targeting O-GlcNAcylation to overcome cancer resistance.

Origin and Therapies of Osteosarcoma

Simple Summary

Osteosarcoma is the most common malignant bone tumor in children, with a 5-year survival rate ranging from 70% to 20% depending on the aggressiveness of the disease. The current treatments have not evolved over the past four decades due in part to the genetic complexity of the disease and its heterogeneity. This review will summarize the current knowledge of OS origin, diagnosis and therapies.

Abstract

Osteosarcoma (OS) is the most frequent primary bone tumor, mainly affecting children and young adults. Despite therapeutic advances, the 5-year survival rate is 70% but drastically decreases to 20–30% for poor responders to therapies or for patients with metastasis. No real evolution of the survival rates has been observed for four decades, explained by poor knowledge of the origin, difficulties related to diagnosis and the lack of targeted therapies for this pediatric tumor. This review will describe a non-exhaustive overview of osteosarcoma disease from a clinical and biological point of view, describing the origin, diagnosis and therapies.

M6 A Demethylase FTO Regulates Cisplatin Resistance of Gastric Cancer by Modulating Autophagy Activation via ULK1

Drug resistance is an important factor for treatment failure of gastric cancer. N⁶‐methyladenosine (m⁶A) is the predominant mRNA internal modification in eukaryotes. The roles of m⁶A modification in drug resistance of gastric cancer remains unclear. In the present study, the m⁶A methylated RNA level was significantly decreased while the expression of m⁶A demethylase fat mass and obesity‐associated protein (FTO) was obviously elevated in cisplatin‐resistant (SGC‐7901/DDP) gastric cancer cells. Knockdown of FTO reversed cisplatin resistance of SGC‐7901/DDP cells both in vitro and in vivo, which was attributed to the inhibition of Unc‐51‐like kinase 1 (ULK1)‐mediated autophagy. Mechanistically, ULK1 expression was regulated in an FTO‐m⁶A‐dependent and YTHDF2‐mediated manner. Collectively, our findings indicate that the FTO/ULK1 axis exerts crucial roles in cisplatin resistance of gastric cancer.

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

Comprehensive Network Analysis of Dysregulated Genes Revealed MNX1‐AS1/ hsa‐miR‐4697‐3p/ HOXB13 Axis in OC Chemotherapy Response

Poor chemotherapy response is the main obstacle of ovarian cancer (OC) treatment. Platinum‐refractory and ‐resistant patients are associated with a worse outcome than platinum‐sensitive and partially sensitive patients, but the comprehensive similarities and differences among them are not yet clear. In this study, we analyzed the data of patients with different chemotherapy response in The Cancer Genome Atlas. We found a minority of altered genes were overlapped in refractory and resistant groups, as did the enriched pathways and Gene Ontology terms. We noticed that the neural signaling and drug metabolism enzymes were more significantly enriched and the protein–protein interaction supported these results. The transcription analysis highlighted PDX1 as the common and central transcription factor in both refractory and resistant groups. The competing endogenous RNA (ceRNA) network shared no common ceRNA pairs, indicating a major difference in noncoding RNA post‐transcriptional regulation. In the end, we validated the expression, regulation, binding, and effect on chemotherapy response for selected MNX1‐AS1/hsa‐miR‐4697‐3p/HOXB13 in OC cell lines. Our study offered a novel and comprehensive insight into chemotherapy response, and potential targets for improving chemotherapy response in OC.

Melatonin Increases the Sensitivity of Osteosarcoma Cells to Chemotherapy Drug Cisplatin

Chemotherapy, which is one of the common treatments for osteosarcoma (OS), has many side effects and in some cases has low effectiveness due to chemoresistance, hence it is vital to study new therapies for OS. In this regard, we combined melatonin with cisplatin and evaluate their effect on MG63 OS cells. Since melatonin has anti-cancer properties, we hypothesized that its combination with cisplatin could increase the effectiveness of cisplatin. Firstly, MTT assay was used to evaluate the cell viability and cytotoxicity of cisplatin on MG63 cells and the results showed that melatonin in combination with cisplatin increases the sensitivity of MG63 cells to cisplatin. In addition, qRT-PCR results showed that the expressions of miR-181 and P53, CYLD, CBX7 and BCL2 genes change in MG63 cells after treatment with the combination of cisplatin and melatonin, so that the expression of P53, CYLD and CBX7 increased and the expression of BCL2 and miR-181b decreases significantly. Furthermore, analysis of Annexin V/FITC assay data revealed that the rate of apoptosis in MG63 OS cell line remarkably promoted after treated with cisplatin and melatonin combination. As a result, our findings show that melatonin in combination with cisplatin increases the effectiveness of cisplatin in osteosarcoma cells and this study provides a new therapeutic approach for OS.

Is Autophagy Always a Barrier to Cisplatin Therapy?

Cisplatin has long been a first-line chemotherapeutic agent in the treatment of cancer, largely for solid tumors. During the course of the past two decades, autophagy has been identified in response to cancer treatments and almost uniformly detected in studies involving cisplatin. There has been increasing recognition of autophagy as a critical factor affecting tumor cell death and tumor chemoresistance. In this review and commentary, we introduce four mechanisms of resistance to cisplatin followed by a discussion of the factors that affect the role of autophagy in cisplatin-sensitive and resistant cells and explore the two-sided outcomes that occur when autophagy inhibitors are combined with cisplatin. Our goal is to analyze the potential for the combinatorial use of cisplatin and autophagy inhibitors in the clinic.

The nerve-tumour regulatory axis GDNF-GFRA1 promotes tumour dormancy, imatinib resistance and local recurrence of gastrointestinal stromal tumours by achieving autophagic flux

Complete surgical resection, accessible therapeutic targets and effective tyrosine kinase inhibitors (TKIs) have not completely cured gastrointestinal stromal tumours (GISTs), with most patients suffering from residual tumours and recurrence. The existence of nerve infiltration in GIST provides a way for tumour cells to escape local resection and systemic targeted therapy, which may challenge the previous understanding of its behaviour patterns and inspire the development of more radical excision and more precise targeted therapy. Moreover, tumour dormancy has emerged as a major cause of drug resistance and tumour relapse. Among these pathways, the nerve-tumour regulatory axis GDNF-GFRA1 is activated in GISTs, assists tumour cells in achieving dormancy and protects them from apoptosis under environmental stress by enhancing autophagic flux. The concrete mechanism is that the GDNF-regulating interaction between GFRA1 and the lysosomal calcium channel MCOLN1 activates Ca²⁺-dependent TFEB signalling. Activated TFEB transcriptionally regulates intracellular lysosome levels, which could achieve feedback upregulation of cellular autophagy flux during TKI treatment. This dormancy-transition axis fills parts of the mechanistic vacancy before the onset of secondary mutations, and strategies for TKIs combined with targeting GFRA1-dependent autophagy have distinct promise as prospective clinical therapies.

Circ-PKD2 promotes Atg13-mediated autophagy by inhibiting miR-646 to increase the sensitivity of cisplatin in oral squamous cell carcinomas

Autophagy is an evolutionally conserved catabolic process that degrades cells to maintain homeostasis. Cisplatin-activated autophagy promotes the expression of circ-PKD2, which plays a role as a tumor suppressor gene in the proliferation, migration, and invasion in oral squamous cell carcinoma (OSCC). However, the role of circ-PKD2 in regulating the sensitivity of OSCC patients to cisplatin remains to be elucidated. Overexpression of circ-PKD2 increased the formation of autophagosomes in OSCC cells and activation of proteins, such as LC3 II/I. Its activation effect on autophagy was, however, alleviated by 3-MA. Bioinformatics analyses and double luciferases reporter assays conducted in this study confirmed the existence of targeted relationships between circ-PKD2 and miR-646 and miR-646 and Atg13. Functional experiments further revealed that miR-646 reversed the autophagy and apoptosis effects of circ-PKD2 in OSCC cells treated with cisplatin. In addition, circ-PKD2 promoted the expression of ATG13 by adsorption of miR-646. Its interference with Atg13 alleviated the activation effects of circ-PKD2 on autophagy and apoptosis of miR-646. Notably, the in vivo animal experiments also confirmed that circ-PKD2 inhibited tumor proliferation and activated autophagy in OSCC cells. This study provides a theoretical basis for using circ-PKD2 as a target to regulate the sensitivity of OSCC patients to cisplatin, thus increasing its chemotherapeutic effects.

Exosomal Long Non-Coding RNA ANCR Mediates Drug Resistance in Osteosarcoma

Osteosarcoma (OS) is rare cancer with bimodal age distribution with peaks observed in children and young adults. Typically, OS is treated with pre-surgery neoadjuvant therapy, surgical excision, and post-surgery chemotherapy. However, the efficacy of treatment on disease prognosis and objective response is not currently optimal, often resulting in drug resistance; in turn, highlighting the need to understand mechanisms driving resistance to therapy in OS patients. Using Doxycycline (Dox)-sensitive and resistant variants of OS cells lines KHOS and U2OS, we found that the resistant variants KHOS-DR and U2OS-DR have significantly higher in vitro proliferation. Treating the Dox-sensitive KHOS/U2OS cells with exosomes isolated from KHOS-DR/U2OS-DR made them resistant to treatment with Dox in vitro and in vivo and enhanced tumor growth and progression, while decreasing overall survival. Expression of the long non-coding RNA (lncRNA) ANCR was significantly higher in the KHOS-DR and U2OS-DR variants. SiRNA-mediated knockdown of ANCR decreased in vitro proliferation, while increasing sensitivity to Dox treatment in the KHOS-DR/U2OS-DR cells. Expression of the exosomal lncRNA ANCR was critical for drug resistance and OS tumor progression in xenografts and was correlated to resistance to Adriamycin and overall survival is patients with OS. These results establish lncRNA ANCR as a critical mediator of resistance to therapy in OS patients, highlighting it as a potential therapeutic target in OS patients.

Investigating the cellular responses of osteosarcoma to cisplatin by confocal Raman microspectroscopy

Confocal Raman Microspectroscopy (CRM) was employed to clarify the cellular response of cisplatin in osteosarcoma (OS) cells with different dosages and incubation times. The K7M2 mouse osteosarcoma cells were treated by cisplatin in 0 μM (UT group), 20 μM (20 T group), and 40 μM (40 T group) doses for 24-h (24H group) and 48-h (48H group), respectively. Raman spectroscopy was utilized to analyze the drug induced variations of intracellular biochemical components in osteosarcoma cells. The spectral results shows that the main changes in its biochemical composition come from nucleic acids. By adopting three different kernel functions (linear, polynomial, and Gaussian radial basis function (RBF)), principal component analysis combined with support vector machine models (PCA-SVM) was built to address the spectral variations among all investigated groups. Meanwhile, multivariate curve resolution alternating least squares (MCR-ALS) was further utilized to discuss on the chemical interpretation on the acquired spectral results. Moreover, Raman spectral images, which is reconstructed by K-means cluster analysis (KCA) with point-scanned hyperspectral dataset, was applied to illustrate the drug induced compositional and morphological variations in each subcellular region. The achieved results not only prove the application potential of Raman based analytical technique in non-labeled intracellular studies, but also illustrate the detailed compositional and structural information of cisplatin induced OS cell responses from the perspective of multivariate analysis and imaging of Raman spectroscopy.

The Emerging Portrait of Glial Cell Line-derived Neurotrophic Factor Family Receptor Alpha (GFRα) in Cancers

Glial cell line-derived neurotrophic factor family receptor alpha (GFRα) members have been widely connected to the mechanisms contributing to cell growth, differentiation, cell migration and tissue maturation. Here we review GFRα biological functions and discussed the evidence indicating whether GFRα signaling complex present novel opportunities for oncogenic intervention and treatment resistance. Thus, our work systematically reviewed the emerging role of GFRα family members in cancers, and provided novel insights for further researches.

Aloin induced apoptosis by enhancing autophagic flux through the PI3K/AKT axis in osteosarcoma

Background

Osteosarcoma is a malignant tumor of bone and soft tissue in adolescents. Due to its tumor biological behavior pattern, osteosarcoma usually generates poor prognosis. Autophagy is an important self-defense mechanism in osteosarcoma.

Methods

Cell viability in IC₅₀ testing and reverse assays was examined by the MTT assay. Cell apoptosis conditions were examined by flow cytometry, Hoechst 33,342 staining and apoptosis-related protein immunoblotting. Autophagy conditions were tested by autophagy-related protein immunoblotting, transmission electron microscopic observation and dual fluorescence autophagy flux detection. The possible targets of aloin were screened out by network pharmacology and bioinformatic methods. Osteosarcoma xenografts in nude BALB/c mice were the model for in vivo research on tumor suppression, autophagy induction, pathway signaling and toxicity tests. In vivo bioluminescence imaging systems, immunohistochemical assays, and gross tumor volume comparisons were applied as the main research methods in vivo.

Results

Aloin induced osteosarcoma apoptosis in a dose-dependent manner. Its possible effects on the PI3K/AKT pathway were screened out by network pharmacology methods. Aloin increased autophagic flux in osteosarcoma by downregulating the PI3K/AKT pathway. Aloin promoted autophagic flux in the osteosarcoma cell lines HOS and MG63 in a dose-dependent manner by promoting autophagosome formation. Chloroquine reversed the apoptosis-promoting and autophagy-enhancing effects of aloin. Autophagy induced by starvation and rapamycin significantly enhanced the autophagic flux and apoptosis induced by aloin, which verified the role of the PI3K/AKT axis in the pharmacological action of aloin. Therapeutic effects, autophagy enhancement and regulatory effects on the PI3K/AKT/mTOR pathway were demonstrated in a nude mouse xenogeneic osteosarcoma transplantation model.

Conclusions

Aloin inhibited the proliferation of osteosarcoma by inhibiting the PI3K/AKT/mTOR pathway, increasing autophagic flux and promoting the apoptosis of osteosarcoma cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-021-00520-4.

Autophagy in Cisplatin Nephrotoxicity during Cancer Therapy

Cisplatin is a widely used chemotherapeutic agent but its clinical use is often limited by nephrotoxicity. Autophagy is a lysosomal degradation pathway that removes protein aggregates and damaged or dysfunctional cellular organelles for maintaining cell homeostasis. Upon cisplatin exposure, autophagy is rapidly activated in renal tubule cells to protect against acute cisplatin nephrotoxicity. Mechanistically, the protective effect is mainly related to the clearance of damaged mitochondria via mitophagy. The role and regulation of autophagy in chronic kidney problems after cisplatin treatment are currently unclear, despite the significance of research in this area. In cancers, autophagy may prevent tumorigenesis, but autophagy may reduce the efficacy of chemotherapy by protecting cancer cells. Future research should focus on developing drugs that enhance the anti-tumor effects of cisplatin while protecting kidneys during cisplatin chemotherapy.

Establishment of an Autophagy-Related Clinical Prognosis Model for Predicting the Overall Survival of Osteosarcoma

Purpose

Osteosarcoma is the most common primary and highly invasive bone tumor in children and adolescents. The purpose of this study is to construct a multi-gene expression feature related to autophagy, which can be used to predict the prognosis of patients with osteosarcoma. Materials and methods. The clinical and gene expression data of patients with osteosarcoma were obtained from the target database. Enrichment analysis of autophagy-related genes related to overall survival (OS-related ARGs) screened by univariate Cox regression was used to determine OS-related ARGs function and signal pathway. In addition, the selected OS-related ARGs were incorporated into multivariate Cox regression to construct prognostic signature for the overall survival (OS) of osteosarcoma. Use the dataset obtained from the GEO database to verify the signature. Besides, gene set enrichment analysis (GSEA) were applied to further elucidate the molecular mechanisms. Finally, the nomogram is established by combining the risk signature with the clinical characteristics.

Results

Our study eventually included 85 patients. Survival analysis showed that patients with low riskScore had better OS. In addition, 16 genes were included in OS-related ARGs. We also generate a prognosis signature based on two OS-related ARGs. The signature can significantly divide patients into low-risk groups and high-risk groups, and has been verified in the data set of GEO. Subsequently, the riskScore, primary tumor site and metastasis status were identified as independent prognostic factors for OS and a nomogram were generated. The C-index of nomogram is 0.789 (95% CI: 0.703~0.875), ROC curve and calibration chart shows that nomogram has a good consistency between prediction and observation of patients.

Conclusions

ARGs was related to the prognosis of osteosarcoma and can be used as a biomarker of prognosis in patients with osteosarcoma. Nomogram can be used to predict OS of patients and improve treatment strategies.

Deficiency of GFRα1 promotes hepatocellular carcinoma progression but enhances oxaliplatin-mediated anti-tumor efficacy

Neurotrophic factors and their receptors have been identified to promote tumor progression. GFRα1, the receptor for glial cell line-derived neurotrophic factor (GDNF), has been demonstrated to be predominantly expressed in adult liver tissue. Our preliminary data showed that GFRα1 is significantly downregulated in hepatocellular carcinoma (HCC) tissue, compared to the matched non-neoplastic tissue. However, the role of GFRα1 in HCC progression remains unknown. Here we found that the expression of GFRα1 in HCC tissue is inversely correlated with the poorer prognosis of HCC patients. Silencing of GFRα1 expression markedly enhances HCC cell growth, tumor metastasis, as well as shortens the survival of HCC tumor-bearing mice. Forced expression of GFRα1 in HCC cells significantly reverses the tumor-promoting effects of GFRα1 silencing, and AAV8-mediated GFRα1 transfection in HCC tumor tissues significantly impedes tumor growth and prolongs the survival of HCC tumor-bearing mice. These results are also verified in vivo in GFRα1 knock-out mice model, with increased DEN-induced HCC carcinogenesis. Mechanistically, GFRα1 could inhibit epithelial-to-mesenchymal transition (EMT) of HCC cells, by upregulating expression of Claudin-1 and ZO-1. Of note, silencing of GFRα1 expression promotes oxaliplatin-mediated HCC cell apoptosis resulting in prolonged survival of HCC-bearing mice, and forced expression of GFRα1 markedly increased oxaliplatin resistance of HCC cells. These results demonstrate that deficiency of GFRα1 promotes HCC progression but enhances chemotherapeutic anti-tumor efficacy, suggesting that GFRα1 may be a candidate prognostic biomarker and a potential therapeutic target in HCC.

Unveiling osteosarcoma responses to DAPT combined with cisplatin by using confocal Raman microscopy

The aim of this study was to clarify the dose- and time-dependent effect of the γ-secretase inhibitor (DAPT) combined with cisplatin on osteosarcoma (OS) cells, evaluated by confocal Raman microspectral imaging (CRMI) technology. The intracellular composition significantly changed after combined drug action compared with the sole cisplatin treatment, proving the synergistic effect of DAPT combined with cisplatin on OS cells. The principal component analysis-linear discriminant analysis revealed the main compositional variations by distinguishing spectral characteristics. K-means cluster and univariate imaging were used to visualize the changes in subcellular morphology and biochemical distribution. The results showed that the increase of the DAPT dose and cisplatin treatment time in the combination treatment induced the division of the nucleus in OS cells, and other organelles also showed significant physiological changes compared with the effect of sole cisplatin treatment. After understanding the cellular response to the combined drug treatment at a molecular level, the achieved results provide an experimental fact for developing suitable individualized tumor treatment protocols.

Characteristics of circRNA and its approach as diagnostic tool in melanoma

One of the most common types of cancer in the world is skin cancer, which has been divided into two groups: non-melanoma and melanoma skin cancer. Different external and internal agents are considered as risk factors for melanoma skin cancer pathogenesis but the exact mechanisms are not yet confirmed. Genetic and epigenetic changes, UV exposure, arsenic compounds, and chemical substances are contributory factors to the development of melanoma. A correlation has emerged between new therapies and the discovery of a basic molecular pattern for skin cancer patients. Circular RNAs (circRNAs) are described as a unique group of extensively expressed endogenous regulatory RNAs with closed-loop structure bonds connecting the 5' and 3' ends, which are commonly expressed in mammalian cells. In this review, we describe the biogenesis of circular RNAs and its function in cancerous conditions focusing on the crosstalk between different circRNAs and melanoma. Increasing evidence suggests that circRNAs appears to be relative to the origin and development of skin-related diseases like malignant melanoma. Different circular RNAs like hsa_circ_0025039, hsa_circRNA006612, circRNA005537, and circANRIL, by targeting different cellular and molecular targets (e.g., CDK4, DAB2IP, ZEB1, miR-889, and let-7 c-3p), can participate in melanoma cancer progression.

miR-339-5p Inhibits Autophagy to Reduce the Resistance of Laryngeal Carcinoma on Cisplatin via Targeting TAK1

Laryngeal carcinoma is a malignant disease with high morbidity and mortality. Several studies have indicated that miRNA dysfunction involves in the development of laryngeal carcinoma. In this study, the connection of miR-339-5p and laryngeal carcinoma was investigated, and qRT-PCR, CCK-8, and flow cytometry assay were used to observe the function of miR-339-5p on laryngeal carcinoma. Besides, the target database, dual-luciferase reporter assay, and western blot were used to explore the regulation mechanism of miR-339-5p on the progression of laryngeal carcinoma. The results showed that miR-339-5p was significantly downregulated in cisplatin-resistant cells of laryngeal carcinoma, and miR-339-5p upregulation could weaken the resistance of laryngeal carcinoma cells on cisplatin. Moreover, miR-339-5p could directly react with 3'-UTR of TAK1, and TAK1 could reverse the effects of miR-339-5p on the progression of autophagy. In conclusion, this study suggests that miR-339-5p can inhibit the autophagy to decrease the cisplatin resistance of laryngeal carcinoma via targeting TAK1.