Cancer Therapeutic Resistance Research Articles

Extracellular vesicles in cancer: Golden goose or trojan horse.

Intercellular communication can be mediated by direct cell-to-cell contact and indirect interactions through secretion of soluble chemokines, cytokines, and growth factors. Extracellular vesicles (EVs) have emerged as important mediators of cell-to-cell and cell-to-environment communications. EVs from tumor cells, immune cells, and stromal cells can remodel the tumor microenvironment and promote cancer cell survival, proliferation, metastasis, immune evasion, and therapeutic resistance. Most importantly, EVs as natural nanoparticles can be manipulated to serve as a potent delivery system for targeted cancer therapy. EVs can be engineered or modified to improve their ability to target tumors and deliver therapeutic substances, such as chemotherapeutic drugs, nucleic acids, and proteins, for the treatment of cancer. This review provides an overview of the biogenesis and recycling of EVs, discusses their roles in cancer development, and highlights their potential as a delivery system for targeted cancer therapy.

IL-1α facilitates GSH synthesis to counteract oxidative stress in oral squamous cell carcinoma under glucose-deprivation

Understanding the intrinsic mechanisms underpinning cancer metabolism and therapeutic resistance is of central importance for effective nutrition-starvation therapies. Here, we report that Interleukin 1A (IL1A) mRNA and IL-1α protein facilitate glutathione (GSH) synthesis to counteract oxidative stress and resistance against nutrition-starvation therapy in oral squamous cell carcinoma (OSCC). The expression of IL1A mRNA was elevated in the case of OSCC associated with unfavorable clinical outcomes. Both IL1A mRNA and IL-1α protein expression were increased under glucose-deprivation in vitro and in vivo. The transcription of IL1A mRNA was regulated in an NRF2-dependent manner in OSCC cell lines under glucose-deprivation. Moreover, the IL-1α conferred resistance to oxidative stress via GSH synthesis in OSCC cell lines. The intratumoral administration of siRNAs against IL1A mRNA markedly reversed GSH production and sensitized OSCC cells to Anlotinib in HN6 xenograft models. Overall, the current study demonstrates novel evidence that the autocrine IL-1α favors endogenous anti-oxidative process and confers therapeutic resistance to nutrition-starvation in OSCCs.

Abstract 386: BACH1 is a key regulator of the tumor hypoxia response

Abstract Hypoxia is an important hallmark of aggressive solid tumors and a key driver of metastasis and resistance to therapy. Hypoxic stress induces the activation of various factors, such as hypoxia-inducible factors (HIFs), which facilitate cellular adaptation and promote tumorigenesis. Given the complexity of this mechanism, identifying novel targets that sensitize hypoxic tumors to therapy could have significant clinical impact. Here we show that the pro-metastatic BTB and CNC homology 1 (BACH1) transcription factor is prolyl-hydroxylated by the HIF Prolyl Hydroxylase (PHD), similar to HIFs, in an oxygen-dependent manner. We describe two major prolyl hydroxylation sites in BACH1 and demonstrate that prolyl hydroxylation increases protein turnover and decreases DNA binding in normoxia. We further demonstrate HIF-independent induction of BACH1 within multiple TNBC (Triple-Negative Breast Cancer) cell lines and patient-derived organoids under hypoxic conditions. Utilizing ChIP-seq, bulk, single-cell and spatial transcriptomics across diverse BACH1 knockout tumor models, our study revealed that BACH1 selectively and directly modulates the transcriptional response associated with hypoxia and stress in TNBC. Our findings identify BACH1 as a clinically relevant target for attenuating hypoxia induced, pro-metastatic signaling and therapeutic resistance in cancers. Citation Format: Long Chi Nguyen, Christopher Dann, Dongbo Yang, Madeline Henn, Emily Shi, Thomas Li, Letícia Stock, Wenchao Liu, Margarite Matossian, Andrea Valdespino, Yoo Jane Han, Jing Zhang, Geetha Priyanka Yerradoddi, Yan Li, Mitsuyo Matsumoto, Olufunmilayo I. Olopade, Kazuhiko Igarashi, Marsha R. Rosner. BACH1 is a key regulator of the tumor hypoxia response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 386.

Abstract 2007: Neurolysin: A novel architect of the prostate cancer microenvironment and therapeutic resistance

Abstract Introduction: Prostate cancer is the second leading cause of cancer-related death in American men, primarily driven by its ability to evade therapeutic interventions. This study uncovers a novel paradigm where neurolysin, a peptidase previously ascribed to neuronal function, orchestrates the tumor microenvironment (TME) by interfacing with cellular motor proteins. This interaction precipitates a series of events that not only fortify the cancer cells' survival but also underpin the resistance to antiandrogen therapies. Experimental Procedures: We deployed advanced prostate cancer models to delve into the extra-neuronal influence of neurolysin, probing its role in the orchestration of the TME. An exhaustive suite of transcriptomic and proteomic analyses, complemented by comprehensive patient cohort studies, laid the foundation for unraveling the complex interplay between neurolysin, motor proteins, and the TME dynamics. Results: Our data elucidates that neurolysin's depletion correlates with an altered TME, conducive to cancer proliferation and resilience against targeted therapies. This shift is mediated through neurolysin's interaction with cellular motor proteins, a liaison that appears to be a cornerstone in TME modulation. A significant subset of prostate cancer cases exhibits a neurolysin deficiency, paralleling more aggressive disease and therapeutic defiance, highlighting its role as a critical biomarker and a novel target for intervention. Conclusions: Neurolysin steps into the limelight as a pivotal modulator of the TME, operating through mechanisms distinct from its known neuronal functions. Its interplay with motor proteins opens a novel avenue in prostate cancer biology, providing a unique perspective on the regulation of the TME and subsequent therapeutic resistance. Targeting this newly discovered regulatory axis presents a promising therapeutic strategy that could potentially redefine the clinical approach to managing prostate cancer and may have implications for other malignancies driven by similar TME alterations. Citation Format: Choushi Wang, Ping Mu. Neurolysin: A novel architect of the prostate cancer microenvironment and therapeutic resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2007.

Abstract 1260: Collapse of cancer cell micronuclei from oxidative damage

Abstract Chromosomal instability, a hallmark of aggressive cancers, disrupts genome integrity through multiple hits by ongoing missegregation of chromosomes. These chromosomes, inherited only by one daughter cell, are subsequently encapsulated in micronuclei (MNi). Micronucleation is detrimental for replication fidelity not only because it sustains chromosomal missegregation, but also because MNi frequently undergo irreversible collapse during interphase exposing their enclosed chromatin to the cytosol. This exposure catalyzes chromosomal rearrangements and heritable epigenetic abnormalities that have been shown to further bolster cancer evolution and therapeutic resistance. Moreover, MNi collapse is known to promote distant metastasis and poor prognosis through eliciting a non-canonical response of otherwise inflammatory signaling pathways. Despite the fundamental role played by MNi catastrophe in compromising genome integrity and sustaining cancer progression, and the subsequent therapeutic potential of targeting this process, the mechanisms underlying MNi collapse are poorly understood. Here, we identify mitochondria-derived reactive oxygen species (ROS) as the main cause of MNi rupture. Notably, we observe that MNi that locate closer to mitochondria are more prone to rupture. Accordingly, increasing ROS chemically and by H2O2 addition increment rupture in a panel of 5 different tumor cell lines, while decreasing ROS using pan-cellular or mitochondrial specific scavengers reduce the frequency of ruptured MNi. By using a combination of advanced super-resolution microscopy, proteomics, transcriptomics, in vitro biochemistry assays, and extensive mutagenesis, we reveal the exact pathway leading to MNi collapse. We demonstrate that ROS promote a noncanonical function of the membrane repair ESCRT-III complex scaffolding protein, CHMP7. ROS reduce CHMP7 interaction with ESCRT-III promoting CHMP7 oligomerization and its binding to the inner nuclear membrane protein, LEMD2. CHMP7, while aggregating, physically pulls the micronuclear envelope together with the LEMD2-associated lamina, thereby disrupting MNi integrity. Finally, we show that hypoxic conditions promote ROS-dependent CHMP7-LEMD2 interaction, inducing MNi rupture and inflammatory signaling. Thus, we observe that human tumors characterized by hypoxia have a significantly increased predominance of ruptured MNi, providing a mechanistic link between tumor hypoxia and downstream processes that drive cancer progression. Citation Format: Melody Di Bona, Yanyang Chen, Albert Agustinus, Matthew Deyell, Mercedes A. Duran, Christy Hong, James Hickling, Daniel Bronder, Sara Martin, Nadeem Riaz, Bill Diplas, Manisha Jalan, Nancy Lee, Alban Ordureau, Benjamin Izar, Ashley Laughney, Simon Powell, Stefano Santaguida, John Maciejowski, Thomas Jeitner, Samuel Bakhoum. Collapse of cancer cell micronuclei from oxidative damage [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1260.

Abstract 7063: Monitoring metabolic plasticity in the tumor microenvironment in vivo by mitophagy generated extracellular vesicles

Abstract Tumor metabolic reprogramming is a hallmark of cancer progression, survival, and therapeutic resistance. A targetable class of cancer metabolic adaptation exploits mitophagy known to be linked to the cancer phenotype. Mitophagy selectively eliminates dysfunctional mitochondria by targeting them, via autophagosome shuttling, to the lysosome for degradation. Cancer cell mitophagy is triggered by elevated oxidative stress and mitochondrial DNA damage caused by hypoxia, radiotherapy, and immunotherapy. A high mitophagy demand can overwhelm the lysosome capacity resulting in the accumulation of damaged mitochondria and can suppress biogenesis of healthy mitochondria. We hypothesize that the newly discovered secretory mitophagy mechanism exports damaged mitochondrial fission-released segments to reduce the overload pressure on the lysosomal system, and thereby sustains cancer cell survival in the face of therapeutic mitochondrial stress. We have discovered a form of secretory mitophagy occurring in vivo in a growing solid tumor. Our molecular analysis of the full repertoire of extracellular vesicles, EVs, shed into the resident tumor interstitial fluid, IF, in vivo yielded a rich set of information about the functional state of mitochondria within the tumor cells, and the host cells. A set of proteins required for sequential steps of fission-induced mitophagy preferentially populated the CD81 positive IF EVs, including PINK1, DRP1 and FIS1. The export of cellular mitochondria proteins to CD81 positive EVs was confirmed by density gradient isolation from the bulk EV isolate followed by anti-CD81 immunoprecipitation, Mito Tracker export into CD81 positive EVs, ultrastructural characterization and Exoview analyzer. Further, we stimulated mitochondrial oxidative stress and blocked the fusion of the mitophagosome with the lysosome, which markedly stimulated the export of the secretory mitophagy unit. The outcome is new understanding of the importance of secretory mitophagy that can constitute a therapeutic target, and a new clinically relevant means of monitoring the in vivo state of mitophagic flux within the tumor microenvironment by means of mitophagy derived EVs. Citation Format: Purva V. Gade, Marissa Howard, Angela Rojas, Layla Hasanzadah, Lance Liotta, Fatah Kashanchi. Monitoring metabolic plasticity in the tumor microenvironment in vivo by mitophagy generated extracellular vesicles [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7063.

Abstract 3935: Involvement of nanoscale physical communication in obesity-associated breast cancer severity

Abstract Obesity is a risk factor for several cancers, including breast cancer, and contributes up to 20% of cancer-related deaths. Growing evidence from both clinical and preclinical studies indicates that increased obesity is associated with increases in cancer incidence, progression, metastasis, and therapeutic resistance. According to the Centers for Disease Control and Prevention (CDC), more than 70% and 40% of American adults can be classified as overweight and obese, respectively. However, treatment strategies for dealing with cancer in obese patients have not advanced apart from lifestyle interventions. However, several signaling mechanisms have been proposed related to the inflammatory and metabolic impact of obese adipocytes in promoting cancer progression. However, a lack of mechanistic understanding led to no specific treatment strategies have been proposed which can specifically downregulate the key regulator by which obese adipocytes promote cancer progression. Thus, translational research initiatives are immediately needed to provide mechanistic justifications for these striking statistics in order to better serve this growing segment of the population. Here, we have shown the role of nanoscale physical communication between breast cancer cells and adipose tissue in promoting cancer progression. Using high-resolution optical and electron microscopy, we have found that breast cancer cells form nanoscale tubular communications with obese adipocytes. Moreover, the cancer cells hijack mitochondria from obese adipocytes. However, coculturing cancer cells and obese adipocytes in the Boyden chamber, allowing exosomal and paracrine communication but blocking direct physical communication, revealed negligible mitochondria transfer. This observation indicates an active transfer of mitochondria via nanotube. A significantly higher rate of mitochondria transfer from obese adipocytes to cancer cells has been observed than non-differentiated pre-adipocytes. The transfer of mitochondria results in an increase in the metabolism of the cancer cells. The mechanistic investigation of the nanotube formation revealed actin's presence as the major component in the nanotube. The exocyst-GTPase protein complex has a prime contribution in actin remodeling and nanotube formation. Inhibition of exocyst-GTPase using a pharmacological inhibitor results in a significant reduction in nanotube-mediated mitochondria transfer. Conclusion: Our goal is to (i) investigate the direct physical connection between adipocytes and cancer cells and the effect on cancer progression and (ii) eliminate mortality related to obesity-associated breast cancer severity by introducing a new therapeutic strategy. Here, we have shown how cancer cells communicate with obese adipocytes and receive additional metabolic power for proliferation. The in vivo investigation of the same is under progress. Citation Format: Tanmoy Saha, Balaaji Baanupriya Srinivasan, Shiladitya Sengupta. Involvement of nanoscale physical communication in obesity-associated breast cancer severity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3935.

Abstract 2782: Characterization of quiescence-associated secretory profile (QuASP) in cancer: A novel defining feature and therapeutic target

Abstract Senescent cells have a unique senescence-associated secretory profile (SASP) and understanding SASP has contributed to numerous advances in knowledge on aging and cancer biology. Quiescence, which is an important yet poorly understood mechanism for chemoresistance, is related but distinct from senescence. Quiescence shares a non-proliferative feature with senescence but is a reversible state in which quiescent cells can reenter the cell cycle. We hypothesized that, analogous to senescent cells, quiescent cells have a distinct quiescence-associated secretory profile (QuASP) and that defining the QuASP will uncover new genes and pathways associated with cancer cell viability and therapeutic resistance. Indeed, suggesting quiescent cells have a unique and biologically important secretome, we found that tumor conditioned medium (TCM) from quiescent ovarian cancer cells (qOvCa) vs. TCM from proliferating cancer cells increased chemoresistance. Similarly, TCM from quiescent cancer cells vs. TCM from proliferating cancer cells suppressed T cell proliferation and INF-gamma/Granzyme B secretion, suggesting a QuASP immunosuppressive effect. RNASeq analysis of qOvCa cells revealed the secreted factor Follistatin (FST) is upregulated in qOvCa and acted as a paracrine pattern to induce chemoresistance. Furthermore, FST was found to be upregulated in peritumoral fluid following chemotherapy and FST levels in patients with OvCa predicted poor prognosis. To identify additional QuASP factors, we used an ER-BIOID labeled system and LC-MS/MS to characterize the secreted proteins from qOvCa induced by serum starvation compared with normal cells in three OvCa cell lines (PT412, PT340, HEY1). Quiescent OvCa cells indeed have a secretome that is highly unique from proliferating cells, with 137/577 upregulated proteins (LFC>1) and 65/577 downregulated proteins (LFC←1 or no detection in quiescence). Several proteins identified as upregulated have been linked to immunosuppression and/or chemoresistance, oncogenesis and cell cycle were selected for validation and further analysis (CLU, VGF, SERPINE1). In conclusion, we find quiescent cells have a unique quiescence associated secretory profile and that the QuASP induces chemoresistance and immunosuppression. As such, this study has important implications for cancer therapy. Citation Format: Qi Jiang, Santiago Panesso-Gómez, Divya Natesan, Matthew L. MacDonald, Ronald J. Buckanovich. Characterization of quiescence-associated secretory profile (QuASP) in cancer: A novel defining feature and therapeutic target [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2782.

Circular RNAs as biomarkers and therapeutic targets for gastrointestinal cancers.

Circular RNAs are a class of noncoding RNAs with covalently linked 5' and 3' ends that arise from backsplicing events. The absence of a 5' cap and a 3' poly(A) tail makes circular RNAs relatively more stable than their linear counterparts. They are evolutionary conserved and tissue-specific, and some show disease-specific expression patterns. Although their biological functions remain largely unknown, circular RNAs have been shown to play regulatory roles by acting as microRNA sponges, regulators of RNA-binding proteins, alternative splicing, and parental gene expression, and they could even encode proteins. Over the past few decades, circular RNAs have attracted wide attention in oncology owing to their implications in various tumors. Many circular RNAs have been characterized as key players in gastrointestinal cancers and influence cancer growth, progression, metastasis, and therapeutic resistance. Accumulating evidence reveals that their unique characteristics, coupled with their critical roles in tumorigenesis, make circular RNAs promising non-invasive clinical biomarkers for gastrointestinal cancers. In the present review, we summarized the biological roles of the emerging circular RNAs and their potential as biomarkers and therapeutic targets, which may help better understand their clinical significance in the management of gastrointestinal cancers.

Circulating microRNAs in Cancer: A 5-Year Update with a Focus on Breast and Lung Cancers.

Circulating microRNAs (c-miRNAs) are non-coding RNAs found in different bodily fluids and are highly investigated for their prognostic potential and biological role in cancer. In this narrative review, we provide an update of the last five years' published papers (2018-2023) on PubMed about c-miRNAs in cancer research. We aim to capture the latest research interests in terms of the highly studied cancers and the insights about c-miRNAs. Our analysis revealed that more than 150 papers focusing on c-miRNAs and cancer were published in the last five years. Among these, there was a high prevalence of papers on breast cancer (BC) and lung cancer (LC), which are estimated to be the most diagnosed cancers globally. Thus, we focus on the main evidence and research trends about c-miRNAs in BC and LC. We report evidence of the effectiveness of c-miRNAs in hot topics of cancer research, such as, early detection, therapeutic resistance, recurrence risk and novel detection platform approaches. Moreover, we look at the deregulated c-miRNAs shared among BC and LC papers, focusing on miR-21 and miR-145. Overall, these data clearly indicate that the role of c-miRNAs in cancer is still a hot topic for oncologic research and that blood is the most investigated matrix.

CAFs vs. TECs: when blood feuds fuel cancer progression, dissemination and therapeutic resistance.

Neoplastic progression involves complex interactions between cancer cells and the surrounding stromal milieu, fostering microenvironments that crucially drive tumor progression and dissemination. Of these stromal constituents, cancer-associated fibroblasts (CAFs) emerge as predominant inhabitants within the tumor microenvironment (TME), actively shaping multiple facets of tumorigenesis, including cancer cell proliferation, invasiveness, and immune evasion. Notably, CAFs also orchestrate the production of pro-angiogenic factors, fueling neovascularization to sustain the metabolic demands of proliferating cancer cells. Moreover, CAFs may also directly or indirectly affect endothelial cell behavior and vascular architecture, which may impact in tumor progression and responses to anti-cancer interventions. Conversely, tumor endothelial cells (TECs) exhibit a corrupted state that has been shown to affect cancer cell growth and inflammation. Both CAFs and TECs are emerging as pivotal regulators of the TME, engaging in multifaceted biological processes that significantly impact cancer progression, dissemination, and therapeutic responses. Yet, the intricate interplay between these stromal components and the orchestrated functions of each cell type remains incompletely elucidated. In this review, we summarize the current understanding of the dynamic interrelationships between CAFs and TECs, discussing the challenges and prospects for leveraging their interactions towards therapeutic advancements in cancer.

Machine learning determines stemness associated with simple and basal-like canine mammary carcinomas

Simple and complex carcinomas are the most common type of malignant Canine Mammary Tumors (CMTs), with simple carcinomas exhibiting aggressive behavior and poorer prognostic. Stemness is an ability associated with cancer initiation, malignancy, and therapeutic resistance, but is still few elucidated in canine mammary tumor subtypes. Here, we first validated, using CMT samples, a previously published canine one-class logistic regression machine learning algorithm (OCLR) to predict stemness (mRNAsi) in canine cancer cells. Then, using the canine mRNAsi, we observed that simple carcinomas exhibit higher stemness than complex carcinomas and other histological subtypes. Also, we confirmed that stemness is higher and associated with basal-like CMTs and with NMF2 metagene signature, a tumor-specific DNA-repair metagene signature. Using correlation analysis, we selected the top 50 genes correlated with higher stemness, and the top 50 genes correlated with lower stemness and further performed a gene set enrichment analysis to observe the biological processes enriched for these genes. Finally, we suggested two promise stemness-associated targets in CMTs, POLA2 and APEX1, especially in simple carcinomas. Thus, our work elucidates stemness as a potential mechanism behind the aggressiveness and development of canine mammary tumors, especially in simple carcinomas, describing evidence of a promising strategy to target this disease.

Immune checkpoints between epithelial-mesenchymal transition and autophagy: A conflicting triangle

Inhibitory immune checkpoint (ICP) molecules are pivotal in inhibiting innate and acquired antitumor immune responses, a mechanism frequently exploited by cancer cells to evade host immunity. These evasion strategies contribute to the complexity of cancer progression and therapeutic resistance. For this reason, ICP molecules have become targets for antitumor drugs, particularly monoclonal antibodies, collectively referred to as immune checkpoint inhibitors (ICI), that counteract such cancer-associated immune suppression and restore antitumor immune responses. Over the last decade, however, it has become clear that tumor cell-associated ICPs can also induce tumor cell-intrinsic effects, in particular epithelial-mesenchymal transition (EMT) and macroautophagy (hereafter autophagy). Both of these processes have profound implications for cancer metastasis and drug responsiveness. This article reviews the positive or negative cross-talk that tumor cell-associated ICPs undergo with autophagy and EMT. We discuss that tumor cell-associated ICPs are upregulated in response to the same stimuli that induce EMT. Moreover, ICPs themselves, when overexpressed, become an EMT-inducing stimulus. As regards the cross-talk with autophagy, ICPs have been shown to either stimulate or inhibit autophagy, while autophagy itself can either up- or downregulate the expression of ICPs. This dynamic equilibrium also extends to the autophagy-apoptosis axis, further emphasizing the complexities of cellular responses. Eventually, we delve into the intricate balance between autophagy and apoptosis, elucidating its role in the broader interplay of cellular dynamics influenced by ICPs. In the final part of this article, we speculate about the driving forces underlying the contradictory outcomes of the reciprocal, inhibitory, or stimulatory effects between ICPs, EMT, and autophagy. A conclusive identification of these driving forces may allow to achieve improved antitumor effects when using combinations of ICIs and compounds acting on EMT and/or autophagy. Prospectively, this may translate into increased and/or broadened therapeutic efficacy compared to what is currently achieved with ICI-based clinical protocols.

Cell state dependent effects of Bmal1 on melanoma immunity and tumorigenicity.

The circadian clock regulator Bmal1 modulates tumorigenesis, but its reported effects are inconsistent. Here, we show that Bmal1 has a context-dependent role in mouse melanoma tumor growth. Loss of Bmal1 in YUMM2.1 or B16-F10 melanoma cells eliminates clock function and diminishes hypoxic gene expression and tumorigenesis, which could be rescued by ectopic expression of HIF1α in YUMM2.1 cells. By contrast, over-expressed wild-type or a transcriptionally inactive mutant Bmal1 non-canonically sequester myosin heavy chain 9 (Myh9) to increase MRTF-SRF activity and AP-1 transcriptional signature, and shift YUMM2.1 cells from a Sox10high to a Sox9high immune resistant, mesenchymal cell state that is found in human melanomas. Our work describes a link between Bmal1, Myh9, mouse melanoma cell plasticity, and tumor immunity. This connection may underlie cancer therapeutic resistance and underpin the link between the circadian clock, MRTF-SRF and the cytoskeleton.

Tolerable glycometabolic stress boosts cancer cell resilience through altered N-glycosylation and Notch signaling activation

Chronic metabolic stress paradoxically elicits pro-tumorigenic signals that facilitate cancer stem cell (CSC) development. Therefore, elucidating the metabolic sensing and signaling mechanisms governing cancer cell stemness can provide insights into ameliorating cancer relapse and therapeutic resistance. Here, we provide convincing evidence that chronic metabolic stress triggered by hyaluronan production augments CSC-like traits and chemoresistance by partially impairing nucleotide sugar metabolism, dolichol lipid-linked oligosaccharide (LLO) biosynthesis and N-glycan assembly. Notably, preconditioning with either low-dose tunicamycin or 2-deoxy-D-glucose, which partially interferes with LLO biosynthesis, reproduced the promoting effects of hyaluronan production on CSCs. Multi-omics revealed characteristic changes in N-glycan profiles and Notch signaling activation in cancer cells exposed to mild glycometabolic stress. Restoration of N-glycan assembly with glucosamine and mannose supplementation and Notch signaling blockade attenuated CSC-like properties and further enhanced the therapeutic efficacy of cisplatin. Therefore, our findings uncover a novel mechanism by which tolerable glycometabolic stress boosts cancer cell resilience through altered N-glycosylation and Notch signaling activation.

Suppression of Bcl3 Disrupts Viability of Breast Cancer Cells through Both p53-Dependent and p53-Independent Mechanisms via Loss of NF-κB Signalling.

The NF-κB co-factor Bcl3 is a proto-oncogene that promotes breast cancer proliferation, metastasis and therapeutic resistance, yet its role in breast cancer cell survival is unclear. Here, we sought to determine the effect of Bcl3 suppression alone on breast cancer cell viability, with a view to informing future studies that aim to target Bcl3 therapeutically. Bcl3 was suppressed by siRNA in breast cancer cell lines before changes in viability, proliferation, apoptosis and senescence were examined. Bcl3 suppression significantly reduced viability and was shown to induce apoptosis in all cell lines tested, while an additional p53-dependent senescence and senescence-associated secretory phenotype was also observed in those cells with functional p53. The role of the Bcl3/NF-κB axis in this senescence response was confirmed via siRNA of the non-canonical NF-κB subunit NFKB2/p52, which resulted in increased cellular senescence and the canonical subunit NFKB1/p50, which induced the senescence-associated secretory phenotype. An analysis of clinical data showed a correlation between reduced relapse-free survival in patients that expressed high levels of Bcl3 and carried a p53 mutation. Together, these data demonstrate a dual role for Bcl3/NF-κB in the maintenance of breast cancer cell viability and suggests that targeting Bcl3 may be more beneficial to patients with tumours that lack functional p53.

The pleiotropic enhancer enh9 promotes cell proliferation and migration in non-small cell lung cancer via ERMP1 and PD-L1

Enhancers, cis-acting DNA elements for transcriptional regulation, are important regulators of cell identity and disease. However, of the hundreds of thousands of enhancers annotated in the human genome, only a few have been studied for their regulatory mechanisms and functions in cancer progression and therapeutic resistance. Here, we report the pleiotropy of one enhancer (named enh9) in both cell proliferation and migration in non-small cell lung cancer (NSCLC) cells. By integrating multi-genomic data, ERMP1 and PD-L1 were screened out as potential targets of enh9. CUT&Tag sequencing demonstrated that enh9 was involved in the genomic interactions between the transcription factor RELA and the promoters of ERMP1 and PD-L1. In addition, ERMP1 and PD-L1 were validated to be involved in cell proliferation and migration, respectively. Our study fully elucidated the function and transcriptional regulation mechanisms of enh9 in NSCLC. The exploration on enhancers is promising to provide new insights for cancer diagnosis and therapy.

Mitochondria driven innate immune signaling and inflammation in cancer growth, immune evasion, and therapeutic resistance.

Mitochondria play an important and multifaceted role in cellular function, catering to the cell's energy and biosynthetic requirements. They modulate apoptosis while responding to diverse extracellular and intracellular stresses including reactive oxygen species (ROS), nutrient and oxygen scarcity, endoplasmic reticulum stress, and signaling via surface death receptors. Integral components of mitochondria, such as mitochondrial DNA (mtDNA), mitochondrial RNA (mtRNA), Adenosine triphosphate (ATP), cardiolipin, and formyl peptides serve as major damage-associated molecular patterns (DAMPs). These molecules activate multiple innate immune pathways both in the cytosol [such as Retionoic Acid-Inducible Gene-1 (RIG-1) and Cyclic GMP-AMP Synthase (cGAS)] and on the cell surface [including Toll-like receptors (TLRs)]. This activation cascade leads to the release of various cytokines, chemokines, interferons, and other inflammatory molecules and oxidative species. The innate immune pathways further induce chronic inflammation in the tumor microenvironment which either promotes survival and proliferation or promotes epithelial to mesenchymal transition (EMT), metastasis and therapeutic resistance in the cancer cell's. Chronic activation of innate inflammatory pathways in tumors also drives immunosuppressive checkpoint expression in the cancer cells and boosts the influx of immune-suppressive populations like Myeloid-Derived Suppressor Cells (MDSCs) and Regulatory T cells (Tregs) in cancer. Thus, sensing of cellular stress by the mitochondria may lead to enhanced tumor growth. In addition to that, the tumor microenvironment also becomes a source of immunosuppressive cytokines. These cytokines exert a debilitating effect on the functioning of immune effector cells, and thus foster immune tolerance and facilitate immune evasion. Here we describe how alteration of the mitochondrial homeostasis and cellular stress drives innate inflammatory pathways in the tumor microenvironment.

Charting the course of ferroptosis research in lung cancer: Insights from a bibliometric analysis

BackgroundLung cancer, a major cause of cancer-related mortality globally, necessitates innovative therapeutic strategies. Ferroptosis, an iron-dependent, non-apoptotic cell death form, has risen as a crucial therapeutic target. This study aims to conduct a comprehensive bibliometric analysis of ferroptosis in lung cancer, highlighting principal research trends, influential publications, and prospective future directions. MethodsThis study utilized bibliometric tools such as VOSviewer, CiteSpace, and the R package “bibliometrix” to thoroughly analyze 488 articles on ferroptosis in lung cancer from 2014 to October 2023. Data from the Web of Science Core Collection were analyzed to determine spatial and temporal trends, identify prominent authors and seminal works, and uncover emerging hotspots and frontiers of the field. The literature was segmented into coherent thematic groups through cluster analysis. ResultsOur analysis revealed a significant exponential growth in publications from 2019 to 2023, mirroring the increasing interest in this area. Predominantly, the influential research was published in high-impact journals, with Scott J. Dixon's works being the most cited. The study identified four primary research themes: Lung Cancer Specifics; Biomarker Identification and Prognosis; Cellular Death Mechanisms and Metabolic Regulation; and Cancer Stem Cells and Therapeutic Resistance. Recent studies have increasingly focused on areas such as the immune microenvironment and mitochondrial dysfunction. Furthermore, the analysis highlighted the field's global collaborative nature, with significant contributions from China, the USA, and Germany. ConclusionThis extensive bibliometric analysis emphasizes the growing importance of ferroptosis in lung cancer research. The identified themes and emerging topics underline the field's complexity and suggest new research avenues. This study promotes a holistic research approach, advocating for the exploration of innovative ferroptosis-targeting therapies that could revolutionize lung cancer treatment.

Single-cell morphological and transcriptome analysis unveil inhibitors of polyploid giant breast cancer cells in vitro

Considerable evidence suggests that breast cancer therapeutic resistance and relapse can be driven by polyploid giant cancer cells (PGCCs). The number of PGCCs increases with the stages of disease and therapeutic stress. Given the importance of PGCCs, it remains challenging to eradicate them. To discover effective anti-PGCC compounds, there is an unmet need to rapidly distinguish compounds that kill non-PGCCs, PGCCs, or both. Here, we establish a single-cell morphological analysis pipeline with a high throughput and great precision to characterize dynamics of individual cells. In this manner, we screen a library to identify promising compounds that inhibit all cancer cells or only PGCCs (e.g., regulators of HDAC, proteasome, and ferroptosis). Additionally, we perform scRNA-Seq to reveal altered cell cycle, metabolism, and ferroptosis sensitivity in breast PGCCs. The combination of single-cell morphological and molecular investigation reveals promising anti-PGCC strategies for breast cancer treatment and other malignancies.