Tumor Cell Survival Research Articles

Abstract PO3-09-05: Potential novel treatments for high-risk subsets of breast cancer in postpartum and African American women

Abstract Semaphorin 7a (SEMA7A) is a neuroimmune molecule first recognized for its roles in axonal guidance and inflammation. More recently, SEMA7A has emerged as a driver of tumor progression in multiple types of cancer including lung, glioblastoma and breast. Our studies have focused on the roles of SEMA7A in promoting tumor cell growth and survival as well as invasion and metastasis in mouse models including xenograft and syngeneic. Using patient samples and datamining we have shown that SEMA7A can predict for recurrence in women with postpartum breast cancer (PPBC), or breast cancers diagnosed within 10 years of recent childbirth, and SEMA7A mRNA expression in TCGA is highest in young and African American (AA) women with BC, who typically have poor prognosis. Additionally, our analysis of the Cancer Genome Atlas (TCGA) breast cancer (n=593) and METABRIC cohorts (n=2,136) revealed that SEMA7A is increased in invasive disease and in the top 9% and 27% of upregulated genes (p=1.09E-19&p=0.009), respectively. Additionally, ~1.2 (TCGA) and ~1.1 (METABRIC) fold increases in SEMA7A mRNA conferred significantly decreased 5-year survival rates (p=0.009&p=0.002) and SEMA7A was in the top 4% of mRNAs upregulated in patients who died within 5 years of diagnosis 20,24-26. Cumulatively, these results suggest that identifying therapeutic vulnerabilities of SEMA7A+BC, or direct targeting of SEMA7A, could improve prognosis for these high-risk populations. We have identified several targets in pre-clinical models of SEMA7A+BC that include clinically available, FDA approved drugs, as well as novel inhibitors that exhibit efficacy. In published studies, we have shown that venetoclax, a Bcl-2 inhibitor, reverses ER+SEMA7A+BC resistance to endocrine therapy in mouse models. In unpublished studies, we have extended our observations in ER+SEMA7A+BC to show that alpelisib and a novel PI3K kinase inhibitor, GCT-007, both inhibit growth of human and mouse mammary tumor cells. Furthermore, in models of ER-SEMA7A+BC where we have shown cells to be resistant to chemotherapy, we have utilized age matched cell lines from AA and CA women to dissect the downstream pro-survival signaling that is mediated by SEMA7A and we have shown that anti-PD-1 and anti-PD-L1 therapies are efficacious in reducing tumor growth in vivo. Finally, we have developed a novel monoclonal antibody-based therapy that directly targets SEMA7A signaling via pro-survival pathways and inhibits tumor growth in vivo and in vitro. Collectively our results suggest that SEMA7A+BC should be identified clinically, and alternative treatments advised for this high-risk subset of breast cancer. Citation Format: Traci Lyons, Lyndsey Crump, Rachel Steinmetz, Kelsey Kines, Heather Fairchild, Alan Elder. Potential novel treatments for high-risk subsets of breast cancer in postpartum and African American women [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-09-05.

Abstract PO5-14-10: Dynamics and prognostic value of subtype specific TROP2 expression in matched pair samples of primary (PBC) and metastatic breast cancer (MBC) tissues

Abstract Background: The genotype and phenotype of breast cancer may change during disease progression. This is of particular interest in the advent of targeted treatment adressing extracellular targets such as TROP2, which serves as chemotherapy carrier rather than being required for tumor cell survival. In addition, technical issues may affect biomarker assessment when comparing primary breast cancer (PBC) tissues with biopsies of metastatic breast cancer (MBC) tissues at distant sites. Here we analyzed TROP2 expression on mRNA level by RT-qPCR in primary tumor and metastatic tissues on basis of molecular subtyping to determine subtype specificity and target gene stability/dynamics. Methods: The tumor bank of a single institution was screened for paraffin-embedded pairs of PBC and MBC tissue samples and a total of 34 matched PBC and MBC pairs were retrieved. RNA was extracted using a bead-based extraction method (RNXtract® IVD kits, Cerca Biotech). Multiplex RT-qPCR was performed using TaqMan® based primer probe sets for ESR1/PGR/ERBB2 and MKI67 (MammaTyper® IVD kits, Cerca Biotech) as well as TROP2 (TargetTyper RUO kits, STRATIFYER Molecular Pathology GmbH). Correlation analysis, Scatter Plots, Partitioning tests and Kaplan Meier analysis were performed using the SAS JMP® 9.0.0 software. Results: Samples from 34 patients with MBC and PBC were available. Positivity of PBC RT-qPCR for ESR1, PGR and HER2 was 78%, 70% and 3%. The overall agreement between matched primary and metastatic lesions 90%, 70% and 100% for RT-qPCR of ESR1, PGR and HER2. Median expression of TROP2 was 2 fold lower in metastatic tissues compared to matched primary tumor tissues, while the lower quartile of mRNA expression dropped 4 fold. In primary tumor tissues TROP2 expression was significantly associated with PGR and HER2 expression (Spearman r=0.5284 p=0.0013 and r=0.3950 p=0.0208; respectively), while no significant association was found for ESR1 and MKI67. In contrast, no significant association with neither PGR nor HER2 was found (Spearman r=0.0461 p=0.8041 and r=0.0461 p=0.7955; respectively), while TROP2 trended to be associated with MKI67 in metastatic lesions (Spearman r=0.3247 p=0.0610). In line with the strong positive association of TROP2 with PGR in primary tumor tissues, elevated TROP2 levels were associated with substantially longer median distant metastasis free survival of 72 months, while TROP2 negative tumors exhibited a median DDFS of only 24 months (p=0,0091). In contrast, no prognostic value for TROP2 mRNA level could be determined from metastatic lesions and determining the time from initial metastasis until death. Conclusion: In this selected matched pair, metastatic cohort, TROP2 mRNA in primary tumors is strongly associated with luminal type of breast cancer expressing higher levels of PGR mRNA, while no such correlation was found in matched metastatic tissues. Moreover, TROP2 is significantly downregulated in metastatic lesions. As TROP2 is expressed in luminal tumors, it may serve as a valuable target for luminal tumors of higher progression risk. However, TROP2 expression is unstable and requires careful decision making on actual biopsies rather than archival tissue samples. Citation Format: Thomas Deutsch, Ralph Wirtz, Stefan Stefanovic, Andreas Hartkopf, Hans-Peter Sinn, Andreas Schneeweiss, Markus Wallwiener. Dynamics and prognostic value of subtype specific TROP2 expression in matched pair samples of primary (PBC) and metastatic breast cancer (MBC) tissues [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-14-10.

Abstract PO5-20-12: A Case of Bilateral Breast Cancer in a patient on Ocrelizumab

Abstract Background: Ocrelizumab is an anti-CD20 B cell depleting monoclonal antibodies that was FDA approved in 2017 for Relapsing-remitting multiple sclerosis and primary progressive multiple sclerosis based on two large phase III trials (OPERA I and ORATORIO)1. In these trials, patients being treated with Ocrelizumab developed more malignancies compared to placebo. Among these cancers, breast cancer was prominent occurring in about 0.5-0.8% of the patients in the Ocrelizumab group as opposed to 0% in the placebo group. Here we present a case of bilateral breast cancer in a patient with Multiple Sclerosis (MS) treated with Ocrelizumab. Case Presentation A 66-year-old woman with a long-standing history of relapsing-remitting multiple sclerosis (MS) presented to us with concerns of bilateral masses on a screening mammogram. She was diagnosed with MS 30 years prior to presentation and was initially treated with multiple immunomodulators. However, she had progression of disease and was started on Ocrelizumab two years prior to presentation. She was up to date with her screening mammograms which had been unrevealing till now. Family history was significant for breast cancer in her grandmother in her 70s. Her annual mammogram screening showed bilateral irregular masses. A subsequent right breast ultrasound showed three breast masses(1cm, 0.5cm and 0.5cm respectively) and her left breast showed a 0.5 cm mass. Biopsy from the right breast showed invasive ductal and lobular carcinoma(ER+, PR+, HER2-) and that from the left breast showed invasive lobular carcinoma(ER+, PR+, HER2-).She underwent bilateral mastectomies and sentinel lymph node biopsies. The surgical margins and lymph nodes were negative for malignancy hence radiation was not warranted. Genetic testing revealed one pathogenic variant in MSH3 but was negative for BRCA1 and 2. Since her Oncotype dx score was low, adjuvant chemotherapy was not offered. She was started on aromatase inhibitor and her Ocrelizumab was permanently discontinued. Discussion Ocrelizumab is one of the immunomodulator drugs for MS with a probable mechanism being B-cell depletion. The mechanism of how it causes breast cancer is unknown. However, suggested theory is that B cell inhibitors can increase the risk of breast cancer by inhibiting the potentially protective role of the B cells. The B cells are thought to play a role in the tumor micro-environments as antigen presenting cells and activators of natural killer and cytolytic T cells targeted toward lysis of tumors. Also, B cell presence, specifically CD20 B cells, is linked to a better prognosis in breast cancer. One study has also pointed out the importance of timing of anti-b cell therapy in relation to cancer morbidity. Treatment of mice with Anti-CD20 therapy prior to tumor challenge did not result in cancer metastasis. Whereas post tumor challenge, there was increased tumor cell survival and metastasis. Our patient although had a family history of breast cancer, did not have a genetic mutation that could have contributed to her breast cancer. Her breast cancer developed after her therapy with Ocrelizumab hence raising suspicion for causation. With rise in the use of immunosuppressive therapies, further data is needed to delineate pathogenesis. Women with MS have lower all-cause survival after breast cancer diagnosis than women without MS. Hence it is important to identify any risk factors or therapies that might be associated with increased risk of cancer. Citation Format: Kriti Mehra, Mohamad Hejazi. A Case of Bilateral Breast Cancer in a patient on Ocrelizumab [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-20-12.

The A986S calcium sensing receptor variant supports the adaptation of breast cancer cells to high calcium — a novel paradigm in breast cancer progression

Breast cancer and other solid tumors that metastasize to bone are frequently accompanied by a progressive increase in circulating calcium as the disease becomes more malignant. The increase in circulating calcium not only disrupts systemic calcium homeostasis but also alters the ability of cells to sense slight changes in extracellular Ca2+ via the ubiquitous calcium sensing receptor (CaSR). Of the CASR polymorphisms at rs1801725 (p.A986S), rs1801726 (p.Q1011E), and rs1042636 (p.R990G) in exon 7 of the receptor, previous studies have shown that only the A986S CaSR variant is associated with calcium in breast, prostate and skin cancers. In this study, we assessed if exon 7 inactivating A986S (AS-CaSR) and Q1011E (QE-CaSR) variants of the receptor influence the survival of breast tumor cells at higher Ca2+. We generated isogenic HEK293T and BT-549 cells expressing these CaSR variants and carried out bulk RNA sequencing of high Ca2+ adapted control and breast cancer cells. CaSR expression was detected by western blotting using anti-flag M2 (Sigma) antibody. By using phospho-ERK1/2 as the readout, the activation of AS-CaSR required higher concentrations of Ca2+ (EC50 ~5.28 mM) compared to the QE-CaSR (EC50 of ~3.81 mM) and the wild type (WT-CaSR; EC50 ~3.69 mM) receptor. When the CaSR variants transfected cells initially cultured at 7.5 mM for 6 days, and then sub-cultured in medium containing 7.5 to 20 mM Ca2+, the viability of empty vector control and WT-CaSR transfected cells strongly decreased at Ca2+ levels beyond 7.5 mM and these cells were mostly necrotic at ≥15 mM Ca2+. The QE-CaSR variant transfected cells on the other hand exhibited limited cell death beyond 10 mM Ca2+, while the surviving colonies of the AS-CaSR variant were viable at up to 15 mM Ca2+ with invasive tendencies. Analysis of differentially expressed genes in high Ca2+ adapted mesenchymal-like BT-549 and epithelial MDA-MB-468 breast cancer cells compared to MCF10A control cells revealed a small set of differentially expressed genes that were significantly associated with relapse free survival of basal-like breast cancer patients. Among these genes are ligands and negative regulators of the WNT/FZD pathway. Our data suggest that the A986S-CaSR variant with reduced sensitivity to Ca2+ supported adaptation of TNBC cells at high Ca2+, and that high Ca2+ adaptation of breast cancer cells may be mediated via a panel of high Ca2+ inducible genes with implications in bone metastasis. This study is supported by NIH SC1GM139814, T32AI007281, T32GM144927, T32HL007737; and the American Cancer Society. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

YY2/BUB3 Axis promotes SAC Hyperactivation and Inhibits Colorectal Cancer Progression via Regulating Chromosomal Instability.

Spindle assembly checkpoint (SAC) is a crucial safeguard mechanism of mitosis fidelity that ensures equal division of duplicated chromosomes to the two progeny cells. Impaired SAC can lead to chromosomal instability (CIN), a well-recognized hallmark of cancer that facilitates tumor progression; paradoxically, high CIN levels are associated with better therapeutic response and prognosis. However, the mechanism by which CIN determines tumor cell survival and therapeutic response remains poorly understood. Here, using a cross-omics approach, YY2 is identified as a mitotic regulator that promotes SAC activity by activating the transcription of budding uninhibited by benzimidazole 3 (BUB3), a component of SAC. While both conditions induce CIN, a defect in YY2/SAC activity enhances mitosis and tumor growth. Meanwhile, hyperactivation of SAC mediated by YY2/BUB3 triggers a delay in mitosis and suppresses growth. Furthermore, it is revealed that YY2/BUB3-mediated excessive CIN causes higher cell death rates and drug sensitivity, whereas residual tumor cells that survived DNA damage-based therapy have moderate CIN and increased drug resistance. These results provide insights into the role of SAC activity and CIN levels in influencing tumor cell survival and drug response, as well as suggest a novel anti-tumor therapeutic strategy that combines SAC activity modulators and DNA-damage agents.

RadPhysBio: A Radiobiological Database for the Prediction of Cell Survival upon Exposure to Ionizing Radiation.

Based on the need for radiobiological databases, in this work, we mined experimental ionizing radiation data of human cells treated with X-rays, γ-rays, carbon ions, protons and α-particles, by manually searching the relevant literature in PubMed from 1980 until 2024. In order to calculate normal and tumor cell survival α and β coefficients of the linear quadratic (LQ) established model, as well as the initial values of the double-strand breaks (DSBs) in DNA, we used WebPlotDigitizer and Python programming language. We also produced complex DNA damage results through the fast Monte Carlo code MCDS in order to complete any missing data. The calculated α/β values are in good agreement with those valued reported in the literature, where α shows a relatively good association with linear energy transfer (LET), but not β. In general, a positive correlation between DSBs and LET was observed as far as the experimental values are concerned. Furthermore, we developed a biophysical prediction model by using machine learning, which showed a good performance for α, while it underscored LET as the most important feature for its prediction. In this study, we designed and developed the novel radiobiological 'RadPhysBio' database for the prediction of irradiated cell survival (α and β coefficients of the LQ model). The incorporation of machine learning and repair models increases the applicability of our results and the spectrum of potential users.

Unveiling the hidden role of extracellular vesicles in brain metastases: a comprehensive review.

Extracellular vesicles (EVs) are small, transparent vesicles that can be found in various biological fluids and are derived from the amplification of cell membranes. Recent studies have increasingly demonstrated that EVs play a crucial regulatory role in tumorigenesis and development, including the progression of metastatic tumors in distant organs. Brain metastases (BMs) are highly prevalent in patients with lung cancer, breast cancer, and melanoma, and patients often experience serious complications and are often associated with a poor prognosis. The immune microenvironment of brain metastases was different from that of the primary tumor. Nevertheless, the existing review on the role and therapeutic potential of EVs in immune microenvironment of BMs is relatively limited. This review provides a comprehensive analysis of the published research literature, summarizing the vital role of EVs in BMs. Studies have demonstrated that EVs participate in the regulation of the BMs immune microenvironment, exemplified by their ability to modify the permeability of the blood-brain barrier, change immune cell infiltration, and activate associated cells for promoting tumor cell survival and proliferation. Furthermore, EVs have the potential to serve as biomarkers for disease surveillance and prediction of BMs. Overall, EVs play a key role in the regulation of the immune microenvironment of brain metastasis and are expected to make advances in immunotherapy and disease diagnosis. Future studies will help reveal the specificmechanisms of EVs in brain metastases and use them as new therapeutic strategies.

Structure-Activity Relationship Studies on Highly Functionalized Pyrazole Hydrazones and Amides as Antiproliferative and Antioxidant Agents.

Aminopyrazoles represent interesting structures in medicinal chemistry, and several derivatives showed biological activity in different therapeutic areas. Previously reported 5-aminopyrazolyl acylhydrazones and amides showed relevant antioxidant and anti-inflammatory activities. To further extend the structure-activity relationships in this class of derivatives, a novel series of pyrazolyl acylhydrazones and amides was designed and prepared through a divergent approach. The novel compounds shared the phenylamino pyrazole nucleus that was differently decorated at positions 1, 3, and 4. The antiproliferative, antiaggregating, and antioxidant properties of the obtained derivatives 10-22 were evaluated in in vitro assays. Derivative 11a showed relevant antitumor properties against selected tumor cell lines (namely, HeLa, MCF7, SKOV3, and SKMEL28) with micromolar IC50 values. In the platelet assay, selected pyrazoles showed higher antioxidant and ROS formation inhibition activity than the reference drugs acetylsalicylic acid and N-acetylcysteine. Furthermore, in vitro radical scavenging screening confirmed the good antioxidant properties of acylhydrazone molecules. Overall, the collected data allowed us to extend the structure-activity relationships of the previously reported compounds and confirmed the pharmaceutical attractiveness of this class of aminopyrazole derivatives.

The C1q and gC1qR axis as a novel checkpoint inhibitor in cancer.

Understanding at the molecular level of the cell biology of tumors has led to significant treatment advances in the past. Despite such advances however, development of therapy resistance and tumor recurrence are still unresolved major challenges. This therefore underscores the need to identify novel tumor targets and develop corresponding therapies to supplement existing biologic and cytotoxic approaches so that a deeper and more sustained treatment responses could be achieved. The complement system is emerging as a potential novel target for cancer therapy. Data accumulated to date show that complement proteins, and in particular C1q and its receptors cC1qR/CR and gC1qR/p33/HABP1, are overexpressed in most cancer cells and together are involved not only in shaping the inflammatory tumor microenvironment, but also in the regulation of angiogenesis, metastasis, and cell proliferation. In addition to the soluble form of C1q that is found in plasma, the C1q molecule is also found anchored on the cell membrane of monocytes, macrophages, dendritic cells, and cancer cells, via a 22aa long leader peptide found only in the A-chain. This orientation leaves its 6 globular heads exposed outwardly and thus available for high affinity binding to a wide range of molecular ligands that enhance tumor cell survival, migration, and proliferation. Similarly, the gC1qR molecule is not only overexpressed in most cancer types but is also released into the microenvironment where it has been shown to be associated with cancer cell proliferation and metastasis by activation of the complement and kinin systems. Co-culture of either T cells or cancer cells with purified C1q or anti-gC1qR has been shown to induce an anti-proliferative response. It is therefore postulated that in the tumor microenvironment, the interaction between C1q expressing cancer cells and gC1qR bearing cytotoxic T cells results in T cell suppression in a manner akin to the PD-L1 and PD-1 interaction.

Dihydrotanshinone I inhibits gallbladder cancer growth by targeting the Keap1-Nrf2 signaling pathway and Nrf2 phosphorylation

BackgroundGallbladder cancer (GBC) poses a significant risk to human health. Its development is influenced by numerous factors, particularly the homeostasis of reactive oxygen species (ROS) within cells. This homeostasis is crucial for tumor cell survival, and abnormal regulation of ROS is associated with the occurrence and progression of many cancers. Dihydrotanshinone I (DHT I), a biologically effective ingredient isolated from Salvia miltiorrhiza, has exhibited cytotoxic properties against various tumor cells by inducing apoptosis. However, the precise molecular mechanisms by which dht I exerts its cytotoxic effects remain unclear. PurposeTo explore the anti-tumor impact of dht I on GBC and elucidate the potential molecular mechanisms. MethodsThe proliferation of GBC cells, NOZ and SGC-996, was assessed using various assays, including CCK-8 assay, colony formation assay and EdU staining. We also examined cell apoptosis, cell cycle progression, ROS levels, and alterations in mitochondrial membrane potential to delve into the intricate molecular mechanism. Quantitative PCR (qPCR), immunofluorescence staining, and Western blotting were performed to evaluate target gene expression at both the mRNA and protein levels. The correlation between nuclear factor erythroid 2-related factor 2 (Nrf2) and kelch-like ECH-associated protein 1 (Keap1) were examined using co-immunoprecipitation. Finally, the in vivo effect of dht I was investigated using a xenograft model of gallbladder cancer in mice. ResultsOur research findings indicated that dht I exerted cytotoxic effects on GBC cells, including inhibiting proliferation, disrupting mitochondrial membrane potential, inducing oxidative stress and apoptosis. Our in vivo studies substantiated the inhibition of dht I on tumor growth in xenograft nude mice. Mechanistically, dht I primarily targeted Nrf2 by promoting Keap1 mediated Nrf2 degradation and inhibiting protein kinase C (PKC) induced Nrf2 phosphorylation. This leads to the suppression of Nrf2 nuclear translocation and reduction of its target gene expression. Moreover, Nrf2 overexpression effectively counteracted the anti-tumor effects of dht I, while Nrf2 knockdown significantly enhanced the inhibitory effect of dht I on GBC. Meanwhile, PKC inhibitors and nuclear import inhibitors increased the sensitivity of GBC cells to dht I treatment. Conversely, Nrf2 activators, proteasome inhibitors, antioxidants and PKC activators all antagonized dht I induced apoptosis and ROS generation in NOZ and SGC-996 cells. ConclusionOur findings indicated that dht I inhibited the growth of GBC cells by regulating the Keap1-Nrf2 signaling pathway and Nrf2 phosphorylation. These insights provide a strong rationale for further investigation of dht I as a potential therapeutic agent for GBC treatment.

Androgen receptor and estrogen receptor variants in prostate and breast cancers

The androgen receptor (AR) and estrogen receptor alpha (ERα) are steroid receptor transcription factors with critical roles in the development and progression of prostate and breast cancers. Advances in the understanding of mechanisms underlying the ligand-dependent activation of these transcription factors have contributed to the development of small molecule inhibitors that block AR and ERα actions. These inhibitors include competitive antagonists and degraders that directly bind the ligand binding domains of these receptors, luteinizing hormone releasing hormone (LHRH) analogs that suppress gonadal synthesis of testosterone or estrogen, and drugs that block specific enzymes required for biosynthesis of testosterone or estrogen. However, resistance to these therapies is frequent, and is often driven by selection for tumor cells with alterations in the AR or ESR1 genes and/or alternatively spliced AR or ESR1 mRNAs that encode variant forms AR or ERα. While most investigations involving AR have been within the context of prostate cancer, and the majority of investigations involving ERα have been within the context of breast cancer, important roles for AR have been elucidated in breast cancer, and important roles for ERα have been elucidated in prostate cancer. Here, we will discuss the roles of AR and ERα in breast and prostate cancers, outline the effects of gene- and mRNA-level alterations in AR and ESR1 on progression of these diseases, and identify strategies that are being developed to target these alterations therapeutically.

Empowering γδ T-cell functionality with vitamin C.

Vitamin C (ascorbic acid) is a potent antioxidant and a cofactor for various enzymes including histone demethylases and methylcytosine dioxygenases. Vitamin C also exerts direct cytotoxicity toward selected tumor cells including colorectal carcinoma. Moreover, vitamin C has been shown to impact immune cell differentiation at various levels including maturation and/or functionality of T cells and their progenitors, dendritic cells, B cells, and NK cells. γδ T cells have recently attracted great interest as effector cells for cell-based cancer immunotherapy, due to their HLA-independent recognition of a large variety of tumor cells. While γδ T cells can thus be also applied as an allogeneic off-the-shelf product, it is obvious that the effector function of γδ T cells needs to be optimized to ensure the best possible clinical efficacy. Here we review the immunomodulatory mechanisms of vitamin C with a special focus on how vitamin C enhances the effector function of γδ T cells. We also discuss future directions of how vitamin C can be used in the clinical setting to boost the efficacy of adoptive cell therapies.

Galectin-8 inhibition and functions in immune response and tumor biology.

Galectins are among organisms' most abundantly expressed lectins (carbohydrate-binding proteins) that specifically bind β-galactosides. They act not only outside the cell, where they bind to extracellular matrix glycans, but also inside the cell, where they have a significant impact on signaling pathways. Galectin-8 is a galectin family protein encoded by the LGALS8 gene. Its role is evident in both T- and B-cell immunity and in the innate immune response, where it acts directly on dendritic cells and induces some pro-inflammatory cytokines. Galectin-8 also plays an important role in the defense against bacterial and viral infections. It is known to promote antibacterial autophagy by recognizing and binding glycans present on the vacuolar membrane, thus acting as a danger receptor. The most important role of galectin-8 is the regulation of cancer growth, metastasis, tumor progression, and tumor cell survival. Importantly, the expression of galectins is typically higher in tumor tissues than in noncancerous tissues. In this review article, we focus on galectin-8 and its function in immune response, microbial infections, and cancer. Given all of these functions of galectin-8, we emphasize the importance of developing new and selective galectin-8 inhibitors and report the current status of their development.

Targeting BRD4: Potential therapeutic strategy for head and neck squamous cell carcinoma (Review).

As a member of BET (bromodomain and extra-terminal) protein family, BRD4 (bromodomain‑containing protein 4) is a chromatin‑associated protein that interacts with acetylated histones and actively recruits regulatory proteins, leading to the modulation of gene expression and chromatin remodeling. The cellular and epigenetic functions of BRD4 implicate normal development, fibrosis and inflammation. BRD4 has been suggested as a potential therapeutic target as it is often overexpressed and plays a critical role in regulating gene expression programs that drive tumor cell proliferation, survival, migration and drug resistance. To address the roles of BRD4 in cancer, several drugs that specifically target BRD4 have been developed. Inhibition of BRD4 has shown promising results in preclinical models, with several BRD4 inhibitors undergoing clinical trials for the treatment of various cancers. Head and neck squamous cell carcinoma (HNSCC), a heterogeneous group of cancers, remains a health challenge with a high incidence rate and poor prognosis. Conventional therapies for HNSCC often cause adverse effects to the patients. Targeting BRD4, therefore, represents a promising strategy to sensitize HNSCC to chemo‑ and radiotherapy allowing de‑intensification of the current therapeutic regime and subsequent reduced side effects. However, further studies are required to fully understand the underlying mechanisms of action of BRD4 in HNSCC in order to determine the optimal dosing and administration of BRD4‑targeted drugs for the treatment of patients with HNSCC.

Mechanisms underlying reversed TRAIL sensitivity in acquired bortezomib-resistant non-small cell lung cancer cells.

Aim: The therapeutic targeting of the tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) death receptors in cancer, including non-small cell lung cancer (NSCLC), is a widely studied approach for tumor selective apoptotic cell death therapy. However, apoptosis resistance is often encountered. The main aim of this study was to investigate the apoptotic mechanism underlying TRAIL sensitivity in three bortezomib (BTZ)-resistant NSCLC variants, combining induction of both the intrinsic and extrinsic pathways. Methods: Sensitivity to TRAIL in BTZ-resistant variants was determined using a tetrazolium (MTT) and a clonogenic assay. A RT-qPCR profiling mRNA array was used to determine apoptosis pathway-specific gene expression. The expression of these proteins was determined through ELISA assays and western Blotting, while apoptosis (sub-G1) and cytokine expression were determined using flow cytometry. Apoptotic genes were silenced by specific siRNAs. Lipid rafts were isolated with fractional ultracentrifugation. Results: A549BTZR (BTZ-resistant) cells were sensitive to TRAIL in contrast to parental A549 cells, which are resistant to TRAIL. TRAIL-sensitive H460 cells remained equally sensitive for TRAIL as H460BTZR. In A549BTZR cells, we identified an increased mRNA expression of TNFRSF11B [osteoprotegerin (OPG)] and caspase-1, -4 and -5 mRNAs involved in cytokine activation and immunogenic cell death. Although the OPG, interleukin-6 (IL-6), and interleukin-8 (IL-8) protein levels were markedly enhanced (122-, 103-, and 11-fold, respectively) in the A549BTZR cells, this was not sufficient to trigger TRAIL-induced apoptosis in the parental A549 cells. Regarding the extrinsic apoptotic pathway, the A549BTZR cells showed TRAIL-R1-dependent TRAIL sensitivity. The shift of TRAIL-R1 from non-lipid into lipid rafts enhanced TRAIL-induced apoptosis. In the intrinsic apoptotic pathway, a strong increase in the mRNA and protein levels of the anti-apoptotic myeloid leukemia cell differentiation protein (Mcl-1) and B-cell leukemia/lymphoma 2 (Bcl-2) was found, whereas the B-cell lymphoma-extra large (Bcl-xL) expression was reduced. However, the stable overexpression of Bcl-xL in the A549BTZR cells did not reverse the TRAIL sensitivity in the A549BTZR cells, but silencing of the BH3 Interacting Domain Death Agonist (BID) protein demonstrated the importance of the intrinsic apoptotic pathway, regardless of Bcl-xL. Conclusion: In summary, increased sensitivity to TRAIL-R1 seems predominantly related to the relocalization into lipid rafts and increased extrinsic and intrinsic apoptotic pathways.

Co-operation of MCL-1 and BCL-XL anti-apoptotic proteins in stromal protection of MM cells from carfilzomib mediated cytotoxicity.

BCL-2 family proteins are important for tumour cell survival and drug resistance in multiple myeloma (MM). Although proteasome inhibitors are effective anti-myeloma drugs, some patients are resistant and almost all eventually relapse. We examined the function of BCL-2 family proteins in stromal-mediated resistance to carfilzomib-induced cytotoxicity in MM cells. Co-cultures employing HS5 stromal cells were used to model the interaction with stroma. MM cells were exposed to CFZ in a 1-hour pulse method. The expression of BCL-2 family proteins was assessed by flow cytometry and WB. Pro-survival proteins: MCL-1, BCL-2 and BCL-XL were inhibited using S63845, ABT-199 and A-1331852 respectively. Changes in BIM binding partners were examined by immunoprecipitation and WB. CFZ induced dose-dependent cell death of MM cells, primarily mediated by apoptosis. Culture of MM cells on HS-5 stromal cells resulted in reduced cytotoxicity to CFZ in a cell contact-dependent manner, upregulated expression of MCL-1 and increased dependency on BCL-XL. Inhibiting BCL-XL or MCL-1 with BH-3 mimetics abrogated stromal-mediated protection only at high doses, which may not be achievable in vivo. However, combining BH-3 mimetics at sub-therapeutic doses, which alone were without effect, significantly enhanced CFZ-mediated cytotoxicity even in the presence of stroma. Furthermore, MCL-1 inhibition led to enhanced binding between BCL-XL and BIM, while blocking BCL-XL increased MCL-1/BIM complex formation, indicating the cooperative role of these proteins. Stromal interactions alter the dependence on BCL-2 family members, providing a rationale for dual inhibition to abrogate the protective effect of stroma and restore sensitivity to CFZ.

Autophagy flux in bladder cancer: Cell death crosstalk, drug and nanotherapeutics

Autophagy, a self-digestion mechanism, has emerged as a promising target in the realm of cancer therapy, particularly in bladder cancer (BCa), a urological malignancy characterized by dysregulated biological processes contributing to its progression. This highly conserved catabolic mechanism exhibits aberrant activation in pathological events, prominently featured in human cancers. The nuanced role of autophagy in cancer has been unveiled as a double-edged sword, capable of functioning as both a pro-survival and pro-death mechanism in a context-dependent manner. In BCa, dysregulation of autophagy intertwines with cell death mechanisms, wherein pro-survival autophagy impedes apoptosis and ferroptosis, while pro-death autophagy diminishes tumor cell survival. The impact of autophagy on BCa progression is multifaceted, influencing metastasis rates and engaging with the epithelial-mesenchymal transition (EMT) mechanism. Pharmacological modulation of autophagy emerges as a viable strategy to impede BCa progression and augment cell death. Notably, the introduction of nanoparticles for targeted autophagy regulation holds promise as an innovative approach in BCa suppression. This review underscores the intricate interplay of autophagy with cell death pathways and its therapeutic implications in the nuanced landscape of bladder cancer.

Abstract LB008: Integrative dynamic MultiOMICs analysis identifies cell cycle and DNA damage response phenotypes as downstream consequences of using the PRMT5 inhibitor AZD3470

Abstract Background: PRMT5 is an epigenetic enzyme that catalyzes symmetric di-methylation of arginine (SDMA) of multiple substrates that regulate biological processes including RNA splicing and cell cycle. The role of PRMT5 in controlling chromatin accessibility has been investigated in some cancer contexts, but its role in non-small cell lung cancer (NSCLC) global chromatin regulation is not known. AstraZeneca has developed an MTA-cooperative PRMT5 inhibitor (AZD3470) that selectively inhibits PRMT5 in MTAP-null tumors and currently is in Phase I clinical trial (NCT06130553, NCT06130553). Here we applied integrative dynamic MultiOMICs analysis upon AZD3470 treatment in six MTAP-null NSCLC cancer cell lines to inform on PRMT5’s function in maintaining tumor cell growth and survival. Methods: Utilizing an integrative approach, our study explored the effects of AZD3470 on human MTAP-deleted NSCLC cells. MultiOMICs analysis including SDMA post-translational modification (PTM) scans, ATAC-seq, RNA-seq, and mass spectrometry proteomics were employed to delineate the immediate effects and downstream phenotypes of AZD3470 PRMT5 inhibition. Results: AZD3470 induced significant SDMA modification of splicing factors consistent with known roles for PRMT5. PRMT5 inhibition by AZD3470 led to changes in global chromatin accessibility in NSCLC cells. Specific changes in genes involved in the cell cycle pathway were observed including CDK6. Integrative analysis of transcriptomics and proteomics data consistently showed alterations in cell cycle, DNA damage repair and splicing related pathways upon treatment, consistent with the established biological roles of PRMT5. Alternative splicing analysis showed that AZD3470 treatment induced a unique retained intron within the ATM gene and resulted in reduced ATM protein levels. Conclusion: Here we identify AZD3470-induced changes to protein post-translational modification, chromatin accessibility, gene expression and RNA splicing in MTAP-deficient NSCLC cancer cell lines. Different area of MultiOMICs data together pointed to changes in cell cycle and DNA repair pathways. Further, we identified alternative splicing of ATM as a consequence of AZD3470 PRMT5i treatment resulting in significant reduction of ATM protein expression. Keywords: AZD3470, NSCLC, PRMT5 Inhibition, Chromatin Accessibility, Alternative Splicing, DNA Repair, ATM Gene. Citation Format: Ted Hong, Steven Criscione, Andrew Jarnuczak, Jelena Urosevic, Stephanie Ashenden, Ghaith Hamza, Praveen Kumar, Nevena Cvetesic, Lauren Bradshaw, Shaun Moore, Daniel Karl, Tianhui Zhang, Abel Sousa, Jonathan Cairns, Anthony Iannetta, Andrew Zhang, Eric Miele, John Reicha, Chris Chambers, Ramy Elgendy, Julia Lindgren, Daniel Jachimowicz, Maryam Clausen, Graham Belfield, Tony Cheung, Michael Grondine, James T. Lynch, Ho Man Chan, Susan Critchlow, Emma Dean. Integrative dynamic MultiOMICs analysis identifies cell cycle and DNA damage response phenotypes as downstream consequences of using the PRMT5 inhibitor AZD3470 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB008.

Thioredoxin Domain Containing 5 (TXNDC5): Friend or Foe?

This review focuses on the thioredoxin domain containing 5 (TXNDC5), also known as endoplasmic reticulum protein 46 (ERp46), a member of the protein disulfide isomerase (PDI) family with a dual role in multiple diseases. TXNDC5 is highly expressed in endothelial cells, fibroblasts, pancreatic β-cells, liver cells, and hypoxic tissues, such as cancer endothelial cells and atherosclerotic plaques. TXNDC5 plays a crucial role in regulating cell proliferation, apoptosis, migration, and antioxidative stress. Its potential significance in cancer warrants further investigation, given the altered and highly adaptable metabolism of tumor cells. It has been reported that both high and low levels of TXNDC5 expression are associated with multiple diseases, such as arthritis, cancer, diabetes, brain diseases, and infections, as well as worse prognoses. TXNDC5 has been attributed to both oncogenic and tumor-suppressive features. It has been concluded that in cancer, TXNDC5 acts as a foe and responds to metabolic and cellular stress signals to promote the survival of tumor cells against apoptosis. Conversely, in normal cells, TXNDC5 acts as a friend to safeguard cells against oxidative and endoplasmic reticulum stress. Therefore, TXNDC5 could serve as a viable biomarker or even a potential pharmacological target.

Equivalent uniform aerobic dose in radiotherapy for hypoxic tumors

Objective. Equivalent uniform aerobic dose (EUAD) is proposed for comparison of integrated cell survival in tumors with different distributions of hypoxia and radiation dose. Approach. The EUAD assumes that for any non-uniform distributions of radiation dose and oxygen enhancement ratio (OER) within a tumor, there is a uniform distribution of radiation dose under hypothetical aerobic conditions with OER = 1 that produces equal integrated survival of clonogenic cells. This definition of EUAD has several advantages. First, the EUAD allows one to compare survival of clonogenic cells in tumors with intra-tumor and inter-tumor variation of radio sensitivity due to hypoxia because the cell survival is recomputed under the same benchmark oxygen level (OER = 1). Second, the EUAD for homogeneously oxygenated tumors is equal to the concept of equivalent uniform dose. Main results. We computed the EUAD using radiotherapy dose and the OER derived from the 18F-Fluoromisonidazole PET (18F-FMISO PET) images of hypoxia in patients with glioblastoma, the most common and aggressive type of primary malignant brain tumor. The 18F-FMISO PET images include a distribution of SUV (Standardized Uptake Value); therefore, the SUV is converted to partial oxygen pressure (pO2) and then to the OER. The prognostic value of EUAD in radiotherapy for hypoxic tumors is demonstrated using correlation between EUAD and overall survival (OS) in radiotherapy for glioblastoma. The correction to the EUAD for the absolute hypoxic volume that traceable to the tumor control probability improves the correlation with OS. Significance. While the analysis proposed in this research is based on the 18F-FMISO PET images for glioblastoma, the EUAD is a universal radiobiological concept and is not associated with any specific cancer or any specific PET or MRI biomarker of hypoxia. Therefore, this research can be generalized to other cancers, for example stage III lung cancer, and to other hypoxia biomarkers.