bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Protein Kinase C Alpha is a Central Node for Tumorigenic Transcriptional Networks in Human Prostate Cancer
Authors: Cooke Mariana , Zhang Xuyao , Zhang Suli , Eruslanov Evgeniy , Lal Priti , Daniel Reba E. , Feldman Michael D. , Abba Martin C. , Kazanietz Marcelo G.
Published: April 2023

Aberrant expression of protein kinase C (PKC) isozymes is a hallmark of cancer. The different members of the PKC family control cellular events associated with cancer development and progression. Whereas the classical/conventional PKCα isozyme has been linked to tumor suppression in most cancer types, here we demonstrate that this kinase is required for the mitogenic activity of aggressive human prostate cancer cells displaying aberrantly high PKCα expression. IHC analysis showed abnormal upregulation of PKCα in human primary prostate tumors. Interestingly, silencing PKCα expression from aggressive prostate cancer cells impairs cell-cycle progression, proliferation, and invasion, as well as their tumorigenic activity in a mouse xenograft model. Mechanistic analysis revealed that PKCα exerts a profound control of gene expression, particularly over genes and transcriptional networks associated with cell-cycle progression and E2F transcription factors. PKCα RNAi depletion from PC3 prostate cancer cells led to a reduction in the expression of proinflammatory cytokine and epithelial-to-mesenchymal transition (EMT) genes, as well as a prominent downregulation of the immune checkpoint ligand PD-L1. This PKCα-dependent gene expression profile was corroborated in silico using human prostate cancer databases. Our studies established PKCα as a multifunctional kinase that plays pleiotropic roles in prostate cancer, particularly by controlling genetic networks associated with tumor growth and progression. The identification of PKCα as a protumorigenic kinase in human prostate cancer provides strong rationale for the development of therapeutic approaches toward targeting PKCα or its effectors.
Significance:
PKCα was found to be aberrantly expressed in human prostate cancer. Silencing the expression of this kinase from aggressive prostate cancer cell lines reduces their proliferative, tumorigenic, and invasive properties. In addition, our findings implicate PKCα as a major node for transcriptional regulation of tumorigenic, inflammatory, and EMT networks in prostate cancer, highlighting its potential relevance as a therapeutic target.
Data from A TCR-like CAR Promotes Sensitive Antigen Recognition and Controlled T-cell Expansion Upon mRNA Vaccination
Authors: Birtel Matthias , Voss Ralf-Holger , Reinhard Katharina , Rengstl Benjamin , Ouchan Yasmina , Michel Kristina , Hayduk Nina , Tillmann Bodo , Becker René , Suchan Martin , Theobald Matthias , Oehm Petra , Türeci Özlem , Sahin Ugur
Published: April 2023

Chimeric antigen receptor (CAR) T cells are efficacious in patients with B-cell malignancies, while their activity is limited in patients with solid tumors. We developed a novel heterodimeric TCR-like CAR (TCAR) designed to achieve optimal chain pairing and integration into the T-cell CD3 signaling complex. The TCAR mediated high antigen sensitivity and potent antigen-specific T-cell effector functions in short-term in vitro assays. Both persistence and functionality of TCAR T cells were augmented by provision of costimulatory signals, which improved proliferation in vitro and in vivo. Combination with a nanoparticulate RNA vaccine, developed for in vivo expansion of CAR T cells, promoted tightly controlled expansion, survival, and antitumor efficacy of TCAR T cells in vivo.
Significance:
A novel TCAR is tightly controlled by RNA vaccine–mediated costimulation and may provide an alternative to second-generation CARs for the treatment of solid tumors.
Data from The MDM2 Inhibitor Navtemadlin Arrests Mouse Melanoma Growth In Vivo and Potentiates Radiotherapy
Authors: Ingelshed Katrine , Spiegelberg Diana , Kannan Pavitra , Påvénius Linnéa , Hacheney Jessica , Jiang Long , Eisinger Silke , Lianoudaki Danai , Lama Dilraj , Castillo Francisca , Bosdotter Cecilia , Kretzschmar Warren W. , Al-Radi Omayma , Fritz Nicolas , Villablanca Eduardo J. , Karlsson Mikael C. I. , Wermeling Fredrik , Nestor Marika , Lane David P. , Sedimbi Saikiran K.
Published: April 2023

The tumor suppressor protein p53 is mutated in close to 50% of human tumors and is dysregulated in many others, for instance by silencing or loss of p14ARF. Under steady-state conditions, the two E3 ligases MDM2/MDM4 interact with and inhibit the transcriptional activity of p53. Inhibition of p53–MDM2/4 interaction to reactivate p53 in tumors with wild-type (WT) p53 has therefore been considered a therapeutic strategy. Moreover, studies indicate that p53 reactivation may synergize with radiation and increase tumor immunogenicity. In vivo studies of most MDM2 inhibitors have utilized immunodeficient xenograft mouse models, preventing detailed studies of action of these molecules on the immune response. The mouse melanoma cell line B16-F10 carries functional, WT p53 but does not express the MDM2 regulator p19ARF. In this study, we tested a p53-MDM2 protein–protein interaction inhibitor, the small molecule Navtemadlin, which is currently being tested in phase II clinical trials. Using mass spectrometry–based proteomics and imaging flow cytometry, we identified specific protein expression patterns following Navtemadlin treatment of B16-F10 melanoma cells compared with their p53 CRISPR-inactivated control cells. In vitro, Navtemadlin induced a significant, p53-dependent, growth arrest but little apoptosis in B16-F10 cells. When combined with radiotherapy, Navtemadlin showed synergistic effects and increased apoptosis. In vivo, Navtemadlin treatment significantly reduced the growth of B16-F10 melanoma cells implanted in C57Bl/6 mice. Our data highlight the utility of a syngeneic B16-F10 p53+/+ mouse melanoma model for assessing existing and novel p53-MDM2/MDM4 inhibitors and in identifying new combination therapies that can efficiently eliminate tumors in vivo.
Significance:
The MDM2 inhibitor Navtemadlin arrests mouse tumor growth and potentiates radiotherapy. Our results support a threshold model for apoptosis induction that requires a high, prolonged p53 signaling for cancer cells to become apoptotic.
Data from The RPL/RPS Gene Signature of Melanoma CTCs Associates with Brain Metastasis
Authors: Bowley Tetiana Y. , Lagutina Irina V. , Francis Carol , Sivakumar Sinduja , Selwyn Reed G. , Taylor Erik , Guo Yan , Fahy Bridget N. , Tawfik Bernard , Marchetti Dario
Published: April 2023

Melanoma brain metastasis (MBM) is linked to poor prognosis and low overall survival. We hypothesized that melanoma circulating tumor cells (CTC) possess a gene signature significantly expressed and associated with MBM. Employing a multipronged approach, we provide first-time evidence identifying a common CTC gene signature for ribosomal protein large/small subunits (RPL/RPS) which associate with MBM onset and progression. Experimental strategies involved capturing, transcriptional profiling, and interrogating CTCs, either directly isolated from blood of patients with melanoma at distinct stages of MBM progression or from CTC-driven MBM in experimental animals. Second, we developed the first MRI CTC-derived MBM xenograft model (MRI-MBM CDX) to discriminate MBM spatial and temporal growth, recreating MBM clinical presentation and progression. Third, we performed the comprehensive transcriptional profiling of MRI-MBM CDXs, along with longitudinal monitoring of CTCs from CDXs possessing and/or not possessing MBM. Our findings suggest that enhanced ribosomal protein content/ribogenesis may contribute to MBM onset. Because ribosome modifications drive tumor progression and metastatic development by remodeling CTC translational events, overexpression of the CTC RPL/RPS gene signature could be implicated in MBM development. Collectively, this study provides important insights for relevance of the CTC RPL/RPS gene signature in MBM, and identify potential targets for therapeutic intervention to improve patient care for patients with melanoma diagnosed with or at high risk of developing MBM.
Significance:
This study reports first evidence of RPL/RPS gene signature driving melanoma brain metastasis. Complex multilevel approach was performed to identify MBM signature and confirm its relevance to clinical settings. Novel MRI CTC-derived MBM mouse xenograft was established to monitor MBM spatial and temporal development and progression.
Data from The Wnt Pathway Inhibitor RXC004 Blocks Tumor Growth and Reverses Immune Evasion in Wnt Ligand–dependent Cancer Models
Authors: Phillips Caroline , Bhamra Inder , Eagle Catherine , Flanagan Eimear , Armer Richard , Jones Clifford D. , Bingham Matilda , Calcraft Peter , Edmenson Cook Alicia , Thompson Ben , Woodcock Simon A.
Published: April 2023

Wnt signaling is implicated in the etiology of gastrointestinal tract cancers. Targeting Wnt signaling is challenging due to on-target toxicity concerns and lack of druggable pathway components. We describe the discovery and characterization of RXC004, a potent and selective inhibitor of the membrane-bound o-acyl transferase Porcupine, essential for Wnt ligand secretion. Absorption, distribution, metabolism, and excretion and safety pharmacology studies were conducted with RXC004 in vitro, and pharmacokinetic exposure assessed in vivo. RXC004 effects on proliferation and tumor metabolism were explored in genetically defined colorectal and pancreatic cancer models in vitro and in vivo. RXC004 effects on immune evasion were assessed in B16F10 immune “cold” and CT26 immune “hot” murine syngeneic models, and in human cell cocultures. RXC004 showed a promising pharmacokinetic profile, inhibited Wnt ligand palmitoylation, secretion, and pathway activation, and demonstrated potent antiproliferative effects in Wnt ligand–dependent (RNF43-mutant or RSPO3-fusion) colorectal and pancreatic cell lines. Reduced tumor growth and increased cancer cell differentiation were observed in SNU-1411 (RSPO3-fusion), AsPC1 and HPAF-II (both RNF43-mutant) xenograft models, with a therapeutic window versus Wnt homeostatic functions. Additional effects of RXC004 on tumor cell metabolism were confirmed in vitro and in vivo by glucose uptake and 18fluorodeoxyglucose-PET, respectively. RXC004 stimulated host tumor immunity; reducing resident myeloid-derived suppressor cells within B16F10 tumors and synergizing with anti-programmed cell death protein-1 (PD-1) to increase CD8+/regulatory T cell ratios within CT26 tumors. Moreover, RXC004 reversed the immunosuppressive effects of HPAF-II cells cocultured with human peripheral blood mononuclear cells, confirming the multiple anticancer mechanisms of this compound, which has progressed into phase II clinical trials.
Significance:
Wnt pathway dysregulation drives many gastrointestinal cancers; however, there are no approved therapies that target the pathway. RXC004 has demonstrated the potential to block both tumor growth and tumor immune evasion in a genetically defined, clinically actionable subpopulation of Wnt ligand–dependent gastrointestinal cancers. The clinical utility of RXC004, and other Porcupine inhibitors, in such Wnt ligand–dependent cancers is currently being assessed in patient trials.
Data from Tumor Cell Extrinsic Synaptogyrin 3 Expression as a Diagnostic and Prognostic Biomarker in Head and Neck Cancer
Authors: Murphy Ryan M. , Tasoulas Jason , Porrello Alessandro , Carper Miranda B. , Tsai Yi-Hsuan , Coffey Alisha R. , Kumar Sunil , Zeng Peter YF. , Schrank Travis P. , Midkiff Bentley R. , Cohen Stephanie , Salazar Ashley H. , Hayward Michele C. , Hayes D. Neil , Olshan Andrew , Gupta Gaorav P. , Nichols Anthony C. , Yarbrough Wendell G. , Pecot Chad V. , Amelio Antonio L.
Published: April 2023

Over 70% of oropharyngeal head and neck squamous cell carcinoma (HNSC) cases in the United States are positive for human papillomavirus (HPV) yet biomarkers for stratifying oropharyngeal HNSC patient risk are limited. We used immunogenomics to identify differentially expressed genes in immune cells of HPV(+) and HPV(−) squamous carcinomas. Candidate genes were tested in clinical specimens using both qRT-PCR and IHC and validated by IHC using the Carolina Head and Neck Cancer Study tissue microarray of HNSC cases. We performed multiplex immunofluorescent staining to confirm expression within the immune cells of HPV(+) tumors, ROC curve analyses, and assessed survival outcomes. The neuronal gene Synaptogyrin-3 (SYNGR3) is robustly expressed in immune cells of HPV(+) squamous cancers. Multiplex immunostaining and single-cell RNA sequencing analyses confirmed SYNGR3 expression in T cells, but also unexpectedly in B cells of HPV(+) tumors. ROC curve analyses revealed that combining SYNGR3 and p16 provides more sensitivity and specificity for HPV detection compared with p16 IHC alone. Patients with SYNGR3-high HNSC have significantly better prognosis with 5-year OS and DSS rates of 60% and 71%, respectively. Moreover, combining p16 localization and SYNGR3 expression can further risk stratify HPV(+) patients such that high cytoplasmic, low nuclear p16 do significantly worse (HR, 8.6; P = 0.032) compared with patients with high cytoplasmic, high nuclear p16. SYNGR3 expression in T and B cells is associated with HPV status and enhanced survival outcomes of patients with HNSC.
Significance:
These findings indicate that codetection of SYNGR3 in immune cells and p16 in tumor cells by IHC can more reliably identify the HPV(+) subgroup of patients with low-risk head and neck cancer that may be appropriate for clinical trials involving treatment deescalation.
Data from Multicenter Phase II Trial of the PARP Inhibitor Olaparib in Recurrent IDH1- and IDH2-mutant Glioma
Authors: Fanucci Kristina , Pilat Mary Jo , Shyr Derek , Shyr Yu , Boerner Scott , Li Jing , Durecki Diane , Drappatz Jan , Puduvalli Vinay , Lieberman Frank Scott , Gonzalez Javier , Giglio Pierre , Ivy S. Percy , Bindra Ranjit S. , Omuro Antonio , LoRusso Patricia
Published: April 2023

Purpose:
Isocitrate dehydrogenase (IDH) 1 and IDH2 mutations (IDH1/2mt) are frequent in glioma. Preclinical studies suggest IDH1/2mts confer “BRCAness” phenotype, a vulnerability that can be targeted through PARP inhibition. To test this hypothesis, we conducted a multicenter study of olaparib monotherapy in patients with IDH1/2mt gliomas.
Methods:
Patients with recurrent, contrast-enhancing IDH1/2mt gliomas were enrolled in a two-step phase II trial; the primary endpoint was overall response rate per Response Assessment in Neuro-Oncology (RANO) criteria. Olaparib 300 mg orally twice daily was given.
Results:
A total of 15 evaluable patients were enrolled. Histology was astrocytoma (N = 12) and oligodendroglioma (N = 3). Most toxicities were grade 1 or 2. Best response was stable disease (SD) in 9 (60%) patients. Median progression-free survival (PFS) was 3.63 months and median overall survival was 20.7 months. For patients with SD, median PFS was 5.53 months; 4 patients had SD for >6 months. Among patients with best response progressive disease (N = 6), 5 had grade 4 tumor and 4 had known CDKN2A alteration. PFS was 5.23 months for grades 2 or 3 tumors (N = 10) versus 1.8 months for grade 4 (N = 5; P = 0.0013).
Conclusion:
The study did not meet the prespecified response-based activity threshold for moving to step 2. However, prolonged SD was observed in patients with grades 2 and 3 histologies, suggesting olaparib monotherapy could be of clinical benefit in select populations. Grade 4 tumors per 2021 World Health Organization classification defined by histology or CDKN2A alteration derived no benefit from this drug, highlighting the usefulness of this classification for future patient stratification and trial design.
Significance:
A single-arm phase II trial of olaparib in IDH-mutant glioma demonstrated clinically significant prolonged SD for select patients with grade 2/3 disease, suggesting potential benefit of olaparib in IDH-mutant gliomas.
Data from Targeting Lymphoma-associated Macrophage Expansion via CSF1R/JAK Inhibition is a Therapeutic Vulnerability in Peripheral T-cell Lymphomas
Authors: Gao Xin , Kady Nermin , Wang Chenguang , Abdelrahman Suhaib , Gann Peter , Sverdlov Maria , Wolfe Ashley , Brown Noah , Reneau John , Robida Aaron M. , Murga-Zamalloa Carlos , Wilcox Ryan A.
Published: April 2023

The reciprocal relationship between malignant T cells and lymphoma-associated macrophages (LAM) within the tumor microenvironment (TME) is unique, as LAMs are well poised to provide ligands for antigen, costimulatory, and cytokine receptors that promote T-cell lymphoma growth. Conversely, malignant T cells promote the functional polarization and homeostatic survival of LAM. Therefore, we sought to determine the extent to which LAMs are a therapeutic vulnerability in these lymphomas, and to identify effective therapeutic strategies for their depletion. We utilized complementary genetically engineered mouse models and primary peripheral T-cell lymphoma (PTCL) specimens to quantify LAM expansion and proliferation. A high-throughput screen was performed to identify targeted agents that effectively deplete LAM within the context of PTCL. We observed that LAMs are dominant constituents of the TME in PTCL. Furthermore, their dominance was explained, at least in part, by their proliferation and expansion in response to PTCL-derived cytokines. Importantly, LAMs are a true dependency in these lymphomas, as their depletion significantly impaired PTCL progression. These findings were extrapolated to a large cohort of human PTCL specimens where LAM proliferation was observed. A high-throughput screen demonstrated that PTCL-derived cytokines led to relative resistance to CSF1R selective inhibitors, and culminated in the identification of dual CSF1R/JAK inhibition as a novel therapeutic strategy to deplete LAM in these aggressive lymphomas. Malignant T cells promote the expansion and proliferation of LAM, which are a bone fide dependency in these lymphomas, and are effectively depleted with a dual CSF1R/JAK inhibitor.
Significance:
LAMs are a therapeutic vulnerability, as their depletion impairs T-cell lymphoma disease progression. Pacritinib, a dual CSF1R/JAK inhibitor, effectively impaired LAM viability and expansion, prolonged survival in preclinical T-cell lymphoma models, and is currently being investigated as a novel therapeutic approach in these lymphomas.
Data from A Phase I Trial of VEGF-A Inhibition Combined with PD-L1 Blockade for Recurrent Glioblastoma
Authors: Chiu Daniel , Qi Jingjing , Thin Tin Htwe , Garcia-Barros Monica , Lee Brian , Hahn Mary , Mandeli John , Belani Puneet , Nael Kambiz , Rashidipour Omid , Ghatan Saadi , Hadjipanayis Constantinos G. , Yong Raymund L. , Germano Isabelle M. , Brody Rachel , Tsankova Nadejda M. , Gnjatic Sacha , Kim-Schulze Seunghee , Hormigo Adília
Published: April 2023

Purpose:
The treatment of glioblastoma (GBM) poses challenges. The use of immune checkpoint inhibition (ICI) has been disappointing as GBM is characterized by low mutational burden and low T-cell infiltration. The combination of ICI with other treatment modalities may improve efficacy.
Patient and Methods:
Patients with recurrent GBM were treated with avelumab, a human IgG1 antibody directed against PD-L1 (part A), or avelumab within a week after laser interstitial thermal therapy (LITT) and continuation of avelumab (part B). Bevacizumab was allowed to be combined with ICI to spare steroid use. The primary objective was to characterize the tolerability and safety of the regimens. The secondary objectives included overall survival, progression-free survival (PFS), signatures of plasma analytes, and immune cells.
Results:
A total of 12 patients (median age 64; range, 37–73) enrolled, five in part A and seven in part B. Two serious adverse events occurred in the same patient, LITT treated, not leading to death. The median survival from enrollment was 13 months [95% confidence interval (CI), 4–16 months] with no differences for part A or B. The median PFS was 3 months (95% CI, 1.5–4.5 months). The decrease in MICA/MICB, γδT cells, and CD4+ T cell EMRA correlated with prolonged survival.
Conclusions:
Avelumab was generally well tolerated. Adding bevacizumab to ICI may be beneficial by lowering cytokine and immune cell expression. The development of this combinatorial treatment warrants further investigation. Exploring the modulation of adaptive and innate immune cells and plasma analytes as biomarker signatures may instruct future studies in this dismal refractory disease.
Significance:
Our phase I of PD-L1 inhibition combined with LITT and using bevacizumab to spare steroids had a good safety profile for recurrent GBM. Developing combinatory treatment may help outcomes. In addition, we found significant immune modulation of cytokines and immune cells by bevacizumab, which may enhance the effect of ICI.
Data from Phase I Trial of Intravenous Mistletoe Extract in Advanced Cancer
Authors: Paller Channing J. , Wang Lin , Fu Wei , Kumar Rajendra , Durham Jennifer N. , Azad Nilofer S. , Laheru Daniel A. , Browner Ilene , Kachhap Sushant K. , Boyapati Kavya , Odeny Thomas , Armstrong Deborah K. , Meyer Christian F. , Gaillard Stephanie , Brahmer Julie R. , Page Ivelisse , Wang Hao , Diaz Luis A.
Published: April 2023

Purpose:
Mistletoe extract (ME) is widely used for patients with cancer to support therapy and to improve quality of life (QoL). However, its use is controversial due to suboptimal trials and a lack of data supporting its intravenous administration.
Materials and Methods:
This phase I trial of intravenous mistletoe (Helixor M) aimed to determine the recommended phase II dosing and to evaluate safety. Patients with solid tumor progressing on at least one line of chemotherapy received escalating doses of Helixor M three times a week. Assessments were also made of tumor marker kinetics and QoL.
Results:
Twenty-one patients were recruited. The median follow-up duration was 15.3 weeks. The MTD was 600 mg. Treatment-related adverse events (AE) occurred in 13 patients (61.9%), with the most common being fatigue (28.6%), nausea (9.5%), and chills (9.5%). Grade 3+ treatment-related AEs were noted in 3 patients (14.8%). Stable disease was observed in 5 patients who had one to six prior therapies. Reductions in baseline target lesions were observed in 3 patients who had two to six prior therapies. Objective responses were not observed. The disease control rate (percentage of complete/partial response and stable disease) was 23.8%. The median stable disease was 15 weeks. Serum cancer antigen-125 or carcinoembryonic antigen showed a slower rate of increase at higher dose levels. The median QoL by Functional Assessment of Cancer Therapy-General increased from 79.7 at week 1 to 93 at week 4.
Conclusions:
Intravenous mistletoe demonstrated manageable toxicities with disease control and improved QoL in a heavily pretreated solid tumor population. Future phase II trials are warranted.
Significance:
Although ME is widely used for cancers, its efficacy and safety are uncertain. This first phase I trial of intravenous mistletoe (Helixor M) aimed to determine phase II dosing and to evaluate safety. We recruited 21 patients with relapsed/refractory metastatic solid tumor. Intravenous mistletoe (600 mg, 3/week) demonstrated manageable toxicities (fatigue, nausea, and chills) with disease control and improved QoL. Future research can examine ME's effect on survival and chemotherapy tolerability.
Data from Mouse Stromal Cells Confound Proteomic Characterization and Quantification of Xenograft Models
Authors: Shi Zhaomei , Mao Binchen , Chen Xiaobo , Hao Piliang , Guo Sheng
Published: April 2023

Xenografts are essential models for studying cancer biology and developing oncology drugs, and are more informative with omics data. Most reported xenograft proteomics projects directly profiled tumors comprising human cancer cells and mouse stromal cells, followed by computational algorithms for assigning peptides to human and mouse proteins. We evaluated the performance of three main algorithms by carrying out benchmark studies on a series of human and mouse cell line mixtures and a set of liver patient-derived xenograft (PDX) models. Our study showed that approximately half of the characterized peptides are common between human and mouse proteins, and their allocations to human or mouse proteins cannot be satisfactorily achieved by any algorithm. As a result, many human proteins are erroneously labeled as differentially expressed proteins (DEP) between samples from the same human cell line mixed with different percentages of mouse cells, and the number of such false DEPs increases superquadratically with the mouse cell percentage. When mouse stromal cells are not removed from PDX tumors, about 30%–40% of DEPs from pairwise comparisons of PDX models are false positives, and about 20% of real DEPs cannot be identified irrespective of the threshold for calling differential expression. In conclusion, our study demonstrated that it is advisable to separate human and mouse cells in xenograft tumors before proteomic profiling to obtain more accurate measurement of species-specific protein expression.
Significance:
This study advocates the separate-then-run over the run-then-separate approach as a better strategy for more reliable proteomic profiling of xenografts.
Data from Regulation of Prostate Androgens by Megalin and 25-hydroxyvitamin D Status: Mechanism for High Prostate Androgens in African American Men
Authors: Garcia Jason , Krieger Kirsten D. , Loitz Candice , Perez Lillian M. , Richards Zachary A. , Helou Yves , Kregel Steve , Celada Sasha , Mesaros Clementina A. , Bosland Maarten , Gann Peter H. , Willnow Thomas E. , Vander Griend Donald , Kittles Rick , Prins Gail S. , Penning Trevor , Nonn Larisa
Published: April 2023

Vitamin D deficiency is associated with an increased risk of prostate cancer mortality and is hypothesized to contribute to prostate cancer aggressiveness and disparities in African American populations. The prostate epithelium was recently shown to express megalin, an endocytic receptor that internalizes circulating globulin-bound hormones, which suggests regulation of intracellular prostate hormone levels. This contrasts with passive diffusion of hormones that is posited by the free hormone hypothesis. Here, we demonstrate that megalin imports testosterone bound to sex hormone-binding globulin into prostate cells. Prostatic loss of Lrp2 (megalin) in a mouse model resulted in reduced prostate testosterone and dihydrotestosterone levels. Megalin expression was regulated and suppressed by 25-hydroxyvitamin D (25D) in cell lines, patient-derived prostate epithelial cells, and prostate tissue explants. In patients, the relationships between hormones support this regulatory mechanism, as prostatic DHT levels are higher in African American men and are inversely correlated with serum 25D status. Megalin levels are reduced in localized prostate cancer by Gleason grade. Our findings suggest that the free hormone hypothesis should be revisited for testosterone and highlight the impact of vitamin D deficiency on prostate androgen levels, which is a known driver of prostate cancer. Thus, we revealed a mechanistic link between vitamin D and prostate cancer disparities observed in African Americans.
Significance:
These findings link vitamin D deficiency and the megalin protein to increased levels of prostate androgens, which may underpin the disparity in lethal prostate cancer in African America men.
Data from Targeting MLL Methyltransferases Enhances the Antitumor Effects of PI3K Inhibition in Hormone Receptor–positive Breast Cancer
Authors: Jones Robert B. , Farhi Jonathan , Adams Miranda , Parwani Kiran K. , Cooper Garrett W. , Zecevic Milica , Lee Richard S. , Hong Andrew L. , Spangle Jennifer M.
Published: April 2023

The high frequency of aberrant PI3K pathway activation in hormone receptor–positive (HR+) breast cancer has led to the development, clinical testing, and approval of the p110α-selective PI3K inhibitor alpelisib. The limited clinical efficacy of alpelisib and other PI3K inhibitors is partially attributed to the functional antagonism between PI3K and estrogen receptor (ER) signaling, which is mitigated via combined PI3K inhibition and endocrine therapy. We and others have previously demonstrated chromatin-associated mechanisms by which PI3K supports cancer development and antagonizes ER signaling through the modulation of the H3K4 methylation axis, inhibition of KDM5A promoter H3K4 demethylation and KMT2D/MLL4-directed enhancer H3K4 methylation. Here we show that inhibition of the H3K4 histone methyltransferase MLL1 in combination with PI3K inhibition impairs HR+ breast cancer clonogenicity and cell proliferation. While combined PI3K/MLL1 inhibition reduces PI3K/AKT signaling and H3K4 methylation, MLL1 inhibition increases PI3K/AKT signaling through the dysregulation of gene expression associated with AKT activation. These data reveal a feedback loop between MLL1 and AKT whereby MLL1 inhibition reactivates AKT. We show that combined PI3K and MLL1 inhibition synergizes to cause cell death in in vitro and in vivo models of HR+ breast cancer, which is enhanced by the additional genetic ablation of the H3K4 methyltransferase and AKT target KMT2D/MLL4. Together, our data provide evidence of a feedback mechanism connecting histone methylation with AKT and may support the preclinical development and testing of pan-MLL inhibitors.
Significance:
Here the authors leverage PI3K/AKT-driven chromatin modification to identify histone methyltransferases as a therapeutic target. Dual PI3K and MLL inhibition synergize to reduce clonogenicity and cell proliferation, and promote in vivo tumor regression. These findings suggest patients with PIK3CA-mutant, HR+ breast cancer may derive clinical benefit from combined PI3K/MLL inhibition.
Data from Three-dimensional Imaging Reveals Immune-driven Tumor-associated High Endothelial Venules as a Key Correlate of Tumor Rejection Following Depletion of Regulatory T Cells
Authors: Milutinovic Stefan , Abe Jun , Jones Emma , Kelch Inken , Smart Kathryn , Lauder Sarah N. , Somerville Michelle , Ware Carl , Godkin Andrew , Stein Jens V. , Bogle Gib , Gallimore Awen
Published: April 2023

High endothelial venules (HEV) are specialized post capillary venules that recruit naïve T cells and B cells into secondary lymphoid organs (SLO) such as lymph nodes (LN). Expansion of HEV networks in SLOs occurs following immune activation to support development of an effective immune response. In this study, we used a carcinogen-induced model of fibrosarcoma to examine HEV remodeling after depletion of regulatory T cells (Treg). We used light sheet fluorescence microscopy imaging to visualize entire HEV networks, subsequently applying computational tools to enable topological mapping and extraction of numerical descriptors of the networks. While these analyses revealed profound cancer- and immune-driven alterations to HEV networks within LNs, these changes did not identify successful responses to treatment. The presence of HEV networks within tumors did however clearly distinguish responders from nonresponders. Finally, we show that a successful treatment response is dependent on coupling tumor-associated HEV (TA-HEV) development to T-cell activation implying that T-cell activation acts as the trigger for development of TA-HEVs which subsequently serve to amplify the immune response by facilitating extravasation of T cells into the tumor mass.
Significance:
We used three-dimensional imaging methods with computational tools to analyze networks of specialized blood vessels called HEVs in LNs and tumors. By applying these techniques in a mouse model of carcinogen-induced tumors, we could identify network changes after depletion of Tregs.
Data from Structures of Cancer Antigen Mesothelin and Its Complexes with Therapeutic Antibodies
Authors: Zhan Jingyu , Lin Dong , Watson Nathan , Esser Lothar , Tang Wai Kwan , Zhang Alex , Liu Xiufen , Hassan Raffit , Gleinich Anne , Shajahan Asif , Azadi Parastoo , Pastan Ira , Xia Di
Published: April 2023

The tumor-associated antigen mesothelin is expressed at high levels on the cell surface of many human cancers, while its expression in normal tissues is limited. The binding of mesothelin to the tumor-associated cancer antigen 125 (CA-125) can lead to heterotypic cell adhesion and tumor metastasis within the pleural and peritoneal cavities. Immunotherapeutic strategies targeting mesothelin are being intensively investigated. Here, we report the crystal structures of mesothelin that reveal a compact, right-handed solenoid consisting of 24 short helices and connecting loops. These helices form a nine-layered spiral coil that resembles ARM/HEAT family proteins. Glycan attachments have been identified in the structure for all three predicted N-glycosylation sites and confirmed with samples from cell culture and patient ascites. The structures of full-length mesothelin and its complex with the Fab of MORAb-009 reveal the interaction of the antibody with the complete epitope, which has not been reported previously. The N-terminal half of mesothelin is conformationally rigid, suitable for eliciting specific antibodies, whereas its C-terminal portion is more flexible. The structure of the C-terminal shedding-resistant fragment of mesothelin complexed with a mAb 15B6 displays an extended linear epitope and helps explain the protection afforded by the antibody for the shedding sites.
Significance:
The structures of full-length mesothelin and its complexes with antibodies reported here are the first to be determined experimentally, providing atomic models for structural organization of this protein and its interactions with antibodies. It offers insights into the function of mesothelin and guidance for further development of therapeutic antibodies.
Data from Combination Chemotherapy of Multidrug-resistant Early-stage Colon Cancer: Determining Optimal Dose Schedules by High-performance Computer Simulation
Authors: Cockrell Chase , Axelrod David E.
Published: April 2023

The goal of this project was to utilize mechanistic simulation to demonstrate a methodology that could determine drug combination dose schedules and dose intensities that would be most effective in eliminating multidrug-resistant cancer cells in early-stage colon cancer. An agent-based model of cell dynamics in human colon crypts was calibrated using measurements of human biopsy specimens. Mutant cancer cells were simulated as cells that were resistant to each of two drugs when the drugs were used separately. The drugs, 5-flurouracil and sulindac, have different mechanisms of action. An artificial neural network was used to generate nearly 200,000 two-drug dose schedules. A high-performance computer simulated each dose schedule as a in silico clinical trial and evaluated each dose schedule for its efficiency to cure (eliminate) multidrug-resistant cancer cells and its toxicity to the host, as indicated by continued crypt function. Among the dose schedules that were generated, 2,430 dose schedules were found to cure all multidrug-resistant mutants in each of the 50 simulated trials and retained colon crypt function. One dose schedule was optimal; it eliminated multidrug-resistant cancer cells with the minimum toxicity and had a time schedule that would be practical for implementation in the clinic. These results demonstrate a procedure to identify which combination drug dose schedules could be most effective in eliminating drug-resistant cancer cells. This was accomplished using a calibrated agent–based model of a human tissue, and a high-performance computer simulation of clinical trials.
Significance:
The results of computer-simulated clinical trials suggest a practical dose schedule for two drugs, 5-fluorouracil and sulindac, that could eliminate multidrug resistant early-stage colon cancer cells with minimum toxicity to the host.
Data from Small-molecule PTPN2 Inhibitors Sensitize Resistant Melanoma to Anti-PD-1 Immunotherapy
Authors: Zhu Zhouting , Tang Rachel , Huff Sarah , Kummetha Indrasena Reddy , Wang Lingling , Li Na , Rana Tariq M.
Published: April 2023

Although immune checkpoint inhibitors targeting T-cell immunoregulatory proteins have revolutionized cancer treatment, they are effective only in a limited number of patients, and new strategies are needed to enhance tumor responses to immunotherapies. Deletion of protein tyrosine phosphatase non-receptor type 2 (Ptpn2), a regulator of growth factor and cytokine signaling pathways, has been shown to sensitize murine B16F10 melanoma cells to IFNγ and anti-PD-1 immunotherapy. Here, we investigated the potential therapeutic utility of small-molecule PTPN2 inhibitors. Ten inhibitors were synthesized on the basis of in silico modeling and structure-based design and functionally tested in vitro and in vivo. We show that the inhibitors had little effect on B16F10 cells alone, but effectively sensitized the tumor cells to IFNγ treatment in vitro and to anti-PD-1 therapy in vivo. Under both conditions, Ptpn2 inhibitor cotreatment suppressed B16F10 cell growth and enhanced Stat1 phosphorylation and expression of IFNγ response genes. In vivo, PTPN2 inhibitor cotreatment significantly reduced melanoma and colorectal tumor growth and enhanced mouse survival compared with anti-PD-1 treatment alone, and this was accompanied by increased tumor infiltration by granzyme B+ CD8+ T cells. Similar results were obtained with representative murine and human colon cancer and lung cancer cell lines. Collectively, these results demonstrate that small-molecule inhibitors of PTPN2 may have clinical utility as sensitizing agents for immunotherapy-resistant cancers.
Significance:
To enhance the effectiveness of immunotherapies in resistant or nonresponsive cancers, it is important to develop inhibitors of enzymes that negatively influence the outcome of treatments. We have designed and evaluated small-molecule inhibitors of PTPN2 demonstrating that these compounds may have clinical utility as sensitizing agents for immunotherapy-resistant cancers.
Data from The WAVE2/miR-29/Integrin-β1 Oncogenic Signaling Axis Promotes Tumor Growth and Metastasis in Triple-negative Breast Cancer
Authors: Rana Priyanka S. , Wang Wei , Markovic Vesna , Szpendyk Justin , Chan Ernest Ricky , Sossey-Alaoui Khalid
Published: April 2023

Breast cancer is the most frequently diagnosed malignancy in women and the major cause of death because of its invasion, metastasis, and resistance to therapies capabilities. The most aggressive subtype of breast cancer is triple-negative breast cancer (TNBC) due to invasive and metastatic properties along with early age of diagnosis and poor prognosis. TNBC tumors do not express estrogen, progesterone, and HER2 receptors, which limits their treatment with targeted therapies. Cancer invasiveness and metastasis are known to be promoted by increased cell motility and upregulation of the WAVE proteins. While the contribution of WAVE2 to cancer progression is well documented, the WAVE2-mediated regulation of TNBC oncogenic properties is still under investigated, as does the molecular mechanisms by which WAVE2 regulates such oncogenic pathways. In this study, we show that WAVE2 plays a significant role in TNBC development, progression, and metastasis, through the regulation of miR-29 expression, which in turn targets Integrin-β1 (ITGB1) and its downstream oncogenic activities. Conversely, we found WAVE2 expression to be regulated by miR-29 in a negative regulatory feedback loop. Reexpression of exogenous WAVE2 in the WAVE2-deficient TNBC cells resulted in reactivation of ITGB1 expression and activity, further confirming the specificity of WAVE2 in regulating Integrin-β1. Together, our data identify a novel WAVE2/miR-29/ITGB1 signaling axis, which is essential for the regulation of the invasion-metastasis cascade in TNBC. Our findings offer new therapeutic strategies for the treatment of TNBC by targeting WAVE2 and/or its downstream effectors.
Significance:
Identification of a novel WAVE2/miR-29/ITGB1 signaling axis may provide new insights on how WAVE2 regulates the invasion-metastasis cascade of TNBC tumors through the modulation of ITGB1 and miR-29.
Data from The Ubiquitin-specific Protease USP36 Associates with the Microprocessor Complex and Regulates miRNA Biogenesis by SUMOylating DGCR8
Authors: Li Yanping , Carey Timothy S. , Feng Catherine H. , Zhu Hong-Ming , Sun Xiao-Xin , Dai Mu-Shui
Published: April 2023

miRNA biogenesis is a cellular process that produces mature miRNAs from their primary transcripts, pri-miRNAs, via two RNAse III enzyme complexes: the Drosha-DGCR8 microprocessor complex in the nucleus and the Dicer-TRBP complex in the cytoplasm. Emerging evidence suggests that miRNA biogenesis is tightly regulated by posttranscriptional and posttranslational modifications and aberrant miRNA biogenesis is associated with various human diseases including cancer. DGCR8 has been shown to be modified by SUMOylation. Yet, the SUMO ligase mediating DGCR8 SUMOylation is currently unknown. Here, we report that USP36, a nucleolar ubiquitin-specific protease essential for ribosome biogenesis, is a novel regulator of DGCR8. USP36 interacts with the microprocessor complex and promotes DGCR8 SUMOylation, specifically modified by SUMO2. USP36-mediated SUMOylation does not affect the levels of DGCR8 and the formation of the Drosha-DGCR8 complex, but promotes the binding of DGCR8 to pri-miRNAs. Consistently, abolishing DGCR8 SUMOylation significantly attenuates its binding to pri-miRNAs and knockdown of USP36 attenuates pri-miRNA processing, resulting in marked reduction of tested mature miRNAs. Induced expression of a SUMOylation-defective mutant of DGCR8 inhibits cell proliferation. Together, these results suggest that USP36 plays an important role in regulating miRNA biogenesis by SUMOylating DGCR8.
Significance:
This study identifies that USP36 mediates DGCR8 SUMOylation by SUMO2 and is critical for miRNA biogenesis. As USP36 is frequently overexpressed in various human cancers, our study suggests that deregulated USP36-miRNA biogenesis pathway may contribute to tumorigenesis.
Data from S100A8/S100A9 Promote Progression of Multiple Myeloma via Expansion of Megakaryocytes
Authors: Lin Cindy , Garcia-Gerique Laura , Bonner Erin E. , Mastio Jerome , Rosenwasser Matthew , Cruz Zachary , Lawler Michael , Bernabei Luca , Muthumani Kar , Liu Qin , Poncz Mortimer , Vogl Thomas , Törngren Marie , Eriksson Helena , Vogl Dan T. , Gabrilovich Dmitry I. , Nefedova Yulia
Published: April 2023

Multiple myeloma is characterized by clonal proliferation of plasma cells that accumulate preferentially in the bone marrow (BM). The tumor microenvironment is one of the leading factors that promote tumor progression. Neutrophils and monocytes are a major part of the BM tumor microenvironment, but the mechanism of their contribution to multiple myeloma progression remains unclear. Here, we describe a novel mechanism by which S100A8/S100A9 proteins produced by BM neutrophils and monocytes promote the expansion of megakaryocytes supporting multiple myeloma progression. S100A8/S100A9 alone was not sufficient to drive megakaryopoiesis but markedly enhanced the effect of thrombopoietin, an effect that was mediated by Toll-like receptor 4 and activation of the STAT5 transcription factor. Targeting S100A9 with tasquinimod as a single agent and in combination with lenalidomide and with proteasome inhibitors has potent antimyeloma effect that is at least partly independent of the adaptive immune system. This newly identified axis of signaling involving myeloid cells and megakaryocytes may provide a new avenue for therapeutic targeting in multiple myeloma.
Significance:
We identified a novel mechanism by which myeloid cells promote myeloma progression independently of the adaptive immune system. Specifically, we discovered a novel role of S100A8/S100A9, the most abundant proteins produced by neutrophils and monocytes, in regulation of myeloma progression via promotion of the megakaryocyte expansion and angiogenesis. Tasquinimod, an inhibitor of S100A9, has potent antimyeloma effects as a single agent and in combination with lenalidomide and with proteasome inhibitors.
Data from The GPER agonist LNS8801 induces mitotic arrest and apoptosis in uveal melanoma cells
Authors: Ambrosini Grazia , Natale Christopher A , Musi Elgilda , Garyantes Tina K , Schwartz Gary K.
Published: April 2023

Abstract
Uveal melanoma is the most common primary intraocular malignancy in adults and has a high incidence of metastatic disease. Current treatments have shown limited clinical activity in uveal melanoma patients with metastasis and there is an urgent need for new effective therapies. Recent findings have shown that women with uveal melanoma have better survival rates than men. The G-protein-coupled estrogen receptor-1 (GPER) has distinct functions from those of the classic estrogen receptors ER/ and its activation by specific agonists has tumor-suppressive roles in several cancers. However, the role of GPER had not previously been investigated in uveal melanoma. We demonstrated that downregulation of GPER in uveal melanoma cells decreased expression of p53 and stimulated cell growth. In contrast, the clinical GPER agonist, LNS8801, upregulated p53 and p21, induced melanocytic differentiation markers, inhibited cell proliferation and cell migration, and induced apoptosis. Furthermore, LNS8801 treatment arrested the cells in G2/M-phase of the cell cycle with concomitant activation of mitotic markers and disruption of the mitotic spindle apparatus. LNS8801 significantly inhibited tumor growth of uveal melanoma xenografts in vivo, suggesting that GPER agonists may be a novel treatment for uveal melanoma.
Factors Associated with Mortality and Long-Term Outcomes of Pediatric Acute Kidney Injury in a Resource Limited Setting
Authors: Alao Michael Abel , Ibrahim Olayinka Rasheed , Ademola Adebowale Dele , Asinobi Adanze Onyenunachi
Published: April 2023

Introduction: Despite being a leading cause of morbidity and mortality globally, acute kidney injury (AKI) is worse in resource-limited areas. This study explores AKI incidence, inhospital mortality, and long-term outcomes in resource-limited settings. Methods: This was a prospective study of children with AKI from 2014 to 2019. KDIGO 2012 defined AKI. We assessed the etiology, inhospital mortality, and long-term outcome of AKI in a mission hospital. Results: Only 169 of 201 AKI patients had complete data. The ages ranged from 1.08 months to 17.5 years; 65.7% were male and 65.1% were from lower socioeconomic class. The incidence of AKI was 59.6 cases per 1,000 persons (95% CI: 5.42, 47.1). Most patients had stage 1 KDIGO AKI (91; 53.8%). 1–5 years old had the highest incidence of AKI (65; 38.5%); sepsis (26.6%), severe malaria (15.4%), and nephrotic syndrome (14.8%) were common AKI causes. Fever (72.8%), pallor (52.1%), and vomiting (45.6%) were the most common symptoms. Thirty-two (27.8%) patients had high blood pressure. Inhospital mortality was 14.8% (95% CI: 9.8, 21.1). The cumulative incidence of AKI-related mortality was 93.2 per 1,000 person-years. Poor outcome was associated with breathlessness, hyponatremia, and leukocytosis. Kaplan-Meier survival curve showed 81% (CI: 74–87%) survival after 5 years of AKI. On Cox proportional-hazards analysis, the absence of breathlessness (HR: 2.537, 95%: CI 1.210–5.317) and hyponatremia (HR: 2.914, 95% CI: 1.343–6.324) were associated with increased survival. Conclusion: In resource-limited settings, infectious diseases and nephrotic syndrome are common causes of AKI. Factors associated with mortality include breathlessness and hyponatremia.