While therapies targeting CD19 by antibodies, CAR-T cells and T cell engagers have improved the response rates in B-cell malignancies; the emergence of resistant cell populations with low CD19 expression can lead to relapsed disease. We developed an in vitro model of adaptive resistance facilitated by chronic exposure of leukemia cells to a CD19-immunotoxin. Single-cell (sc) RNAseq showed increase in transcriptionally distinct CD19low populations in resistant cells. Mass cytometry demonstrated that CD22 was also decreased in these CD19low resistant cells. ATAC-seq showed decreased chromatin accessibility at promoters of both CD19 and CD22 during development of resistance. Combined loss of both CD19 and CD22 antigens was validated in samples from pediatric and young adult patients with ALL that relapsed after CD19 CAR-T targeted therapy. Functionally, resistant cells were characterized by slower growth and lower basal levels of MEK activation. CD19low resistant cells exhibited preserved B cell receptor signaling and were more sensitive to both BTK and MEK inhibition. These data demonstrate that resistance to CD19 immunotherapies can result in decreased expression of both CD19 and CD22 and can result in dependency on BTK pathways.
Sarah Aminov, Orsi Giricz, David T. Melnekoff, R. Alejandro Sica, Veronika Polishchuk, Cristian Papazoglu, Bonnie Yates, Hao-Wei Wang, Srabani Sahu, Yanhua Wang, Shanisha Gordon-Mitchell, Violetta V. Leshchenko, Carolina Schinke, Kith Pradhan, Srinivas Aluri, Moah Sohn, Stefan K. Barta, Beamon Agarwal, Mendel Goldfinger, Ioannis Mantzaris, Aditi Shastri, William Matsui, Ulrich Steidl, Joshua D. Brody, Nirali N. Shah, Samir Parekh, Amit Verma
Corticosteroid treatment (CST) failure is associated with poor outcomes for patients with gastrointestinal graft-versus-host disease (GI GVHD). CST is intended to target the immune system, but the glucocorticoid receptor is widely expressed, including within the intestines, where its effects are poorly understood. Here, we report that corticosteroids directly target intestinal epithelium, potentially worsening immune-mediated GI damage. Corticosteroids administered to mice in vivo and intestinal organoid cultures ex vivo reduced epithelial proliferation. Following irradiation, immediate CST mitigated GI damage, but delayed treatment attenuated regeneration and exacerbated damage. In a murine steroid-refractory GVHD model, CST impaired epithelial regeneration, worsened crypt loss, and reduced intestinal stem cell (ISC) frequencies. CST also exacerbated immune-mediated damage in organoid cultures with “steroid-refractory” GR-deficient T cells or Interferon-γ. These findings correlated with corticosteroid-dependent changes in apoptosis-related gene expression and STAT3-related epithelial proliferation. Conversely, Interleukin-22 administration enhanced STAT3 activity and overcame corticosteroid-mediated attenuation of regeneration, reducing crypt loss and promoting ISC expansion in steroid-treated mice with GVHD. Therefore, CST has the potential to exacerbate GI damage if it fails to control the damage-inducing immune response, but this risk may be countered by strategies augmenting epithelial regeneration, thus providing rationale for clinical approaches combining such tissue-targeted therapies with immunosuppression.
Viktor Arnhold, Winston Y. Chang, Suze A. Jansen, Govindarajan Thangavelu, Marco Calafiore, Paola Vinci, Ya-Yuan Fu, Takahiro Ito, Shuichiro Takashima, Anastasiya Egorova, Jason Kuttiyara, Adam Perlstein, Marliek van Hoesel, Chen Liu, Bruce R. Blazar, Caroline A. Lindemans, Alan M. Hanash
Radiotherapy (RT) is considered immunogenic, but clinical data demonstrating RT-induced T-cell priming are scarce. Here, we show in a mouse tumor model representative of human lymphocyte-depleted cancer that RT enhances spontaneous priming of thymus-derived (FOXP3+ Helios+) regulatory T-cells (Tregs) by the tumor. These Tregs acquire an effector phenotype, populate the tumor and impede tumor control by a simultaneous, RT-induced CD8+ cytotoxic T-cell (CTL) response. Combination of RT with CTLA-4 or PD-1 blockade, which enables CD28 costimulation, further increased this Treg response and failed to improve tumor control. We discovered that upon RT, CD28-ligands CD86 and CD80 differentially affected the Treg response. CD86, but not CD80, blockade prevented the effector (e)Treg response, enriched the tumor-draining lymph node for PD-L1+CD80+ migratory, conventional dendritic cells (cDCs) and promoted CTL priming. Blockade of CD86 alone or in combination with PD-1, enhanced intra-tumoral CTL accumulation and the combination significantly increased RT-induced tumor regression and overall survival. We advise that combining RT with PD-1 and/or CTLA-4 blockade may be counterproductive in lymphocyte-depleted cancers, since they drive Treg responses in this context. However, combining RT with CD86 blockade may promote control of such tumors by enabling a CTL response.
Elselien Frijlink, Douwe M.T. Bosma, Julia Busselaar, Thomas W. Battaglia, Mo D. Staal, Inge Verbrugge, Jannie Borst
Neutrophil (PMN) tissue accumulation is an established feature of ulcerative colitis (UC) lesions and colorectal cancer (CRC). To assess the PMN phenotypic and functional diversification during inflammatory ulceration to CRC transition we analyzed the transcriptomic landscape of blood and tissue PMNs. Transcriptional programs effectively separated PMNs based on their localization to peripheral blood, inflamed colon, and tumors. In silico pathway overrepresentation analysis, protein-network mapping, gene signature identification, and gene-ontology scoring revealed unique enrichment of angiogenic and vasculature development pathways in tumor-associated neutrophils (TANs). Functional studies utilizing ex vivo cultures, colitis-induced murine CRC, and patient-derived xenograft models demonstrated a critical role for TANs in promoting tumor vascularization. Spp1 (OPN) and Mmp14 (MT1-MMP) were identified by unbiased -omics and mechanistic studies to be highly induced in TANs, acting to critically regulate endothelial cell chemotaxis and branching. TCGA dataset and clinical specimens confirmed enrichment of SPP1 and MMP14 in high-grade CRC but not in UC patients. Pharmacological inhibition of TAN trafficking or MMP14 activity effectively reduced tumor vascular density, leading to CRC regression. Our findings, demonstrate a niche-directed PMN functional specialization, and identify TAN contributions to tumor vascularization, delineating a new therapeutic framework for CRC treatment focused on TAN angiogenic properties.
Triet M. Bui, Lenore K. Yalom, Edward Ning, Jessica M. Urbanczyk, Xingsheng Ren, Caroline J. Herrnreiter, Jackson A. DiSario, Brian Wray, Matthew J. Schipma, Yuri S. Velichko, David P. Sullivan, Kouki Abe, Shannon M. Lauberth, Guang-Yu Yang, Parambir S. Dulai, Stephen B. Hanauer, Ronen Sumagin
Epigenetics is a biological process that modifies and regulates gene expression, affects neuronal function, and contributes to pain. However, the mechanism by which epigenetics facilitates and maintains chronic pain is poorly understood. We aimed to determine whether N6-methyladenosine (m6A) specifically modified by methyltransferase 14 (METTL14) alters neuronal activity and governs pain by sensitizing the GluN2A subunit of the N-methyl-D-aspartate receptor (NMDAR) in the dorsal root ganglion (DRG) neurons in a model of chemotherapy-induced neuropathic pain (CINP). Using dot blotting, immunofluorescence, gain/loss-of-function, and behavioral assays, we found that m6A levels were upregulated in L4–L6 DRG neurons in the CINP in a DBP/METT14-dependent manner, which was also confirmed in human DRGs. Blocking METTL14 reduced m6A methylation and attenuated pain hypersensitivity. Mechanistically, METTL14-mediated m6A modification facilitated the synaptic plasticity of DRG neurons by enhancing the GluN2A subunit of NMDAR, and inhibiting METTL14 blocked this effect. In contrast, overexpression of METTL14 upregulated m6A modifications, enhanced presynaptic NMDAR activity in DRG neurons, and facilitated pain sensation. Our findings reveal a previously unrecognized mechanism of METTL14-mediated m6A modification in DRG neurons to maintain neuropathic pain. Targeting these molecules may provide a new strategy for pain treatment.
Weicheng Lu, Xiaohua Yang, Weiqiang Zhong, Guojun Chen, Xinqi Guo, Qingqing Ye, Yixin Xu, Zhenhua Qi, Yaqi Ye, Jingyun Zhang, Yuge Wang, Xintong Wang, Shu Wang, Qiyue Zhao, Weian Zeng, Junting Huang, Huijie Ma, Jingdun Xie
Diffuse midline glioma (DMG), including tumors diagnosed in the brainstem (diffuse intrinsic pontine glioma – DIPG), are uniformly fatal brain tumors that lack effective treatment. Analysis of CRISPR-Cas9 loss-of-function gene deletion screens identified PIK3CA and MTOR as targetable molecular dependencies across DIPG patient models, highlighting the therapeutic potential of the blood-brain barrier penetrant PI3K/Akt/mTOR inhibitor, paxalisib. At the human equivalent maximum tolerated dose, mice treated with paxalisib experienced systemic glucose feedback and increased insulin levels commensurate with patients using PI3K inhibitors. To exploit genetic dependence and overcome resistance whilst maintaining compliance and therapeutic benefit, we combined paxalisib with the anti-hyperglycemic drug, metformin. Metformin restored glucose homeostasis and decreased phosphorylation of the insulin receptor in vivo, a common mechanism of PI3K-inhibitor resistance, extending survival of orthotopic models. DIPG models treated with paxalisib increased calcium-activated PKC signaling. The brain penetrant PKC inhibitor enzastaurin in combination with paxalisib, synergistically extended the survival of multiple orthotopic patient-derived and immunocompetent syngeneic allograft models; benefits potentiated in combination with metformin and standard-of-care radiotherapy. Therapeutic adaptation was assessed using spatial transcriptomics and ATAC-sequencing, identifying changes in myelination and tumor immune microenvironment crosstalk. Together, we have identified a clinically relevant DIPG therapeutic combinatorial approach.
Ryan J. Duchatel, Evangeline R. Jackson, Sarah G. Parackal, Dylan Kiltschewskij, Izac J. Findlay, Abdul Mannan, Dilana E. Staudt, Bryce C. Thomas, Zacary P. Germon, Sandra Laternser, Padraic S. Kearney, M. Fairuz B. Jamaluddin, Alicia M. Douglas, Tyrone S. Beitaki, Holly P. McEwen, Mika L. Persson, Emily A. Hocke, Vaibhav Jain, Michael Aksu, Elizabeth E. Manning, Heather C. Murray, Nicole M. Verrills, Claire Xin Sun, Paul Daniel, Ricardo E. Vilain, David A. Skerrett-Byrne, Brett Nixon, Susan Hua, Charles E. de Bock, Yolanda Colino-Sanguino, Fatima Valdes-Mora, Maria Tsoli, David S. Ziegler, Murray J. Cairns, Eric H. Raabe, Nicholas A. Vitanza, Esther Hulleman, Timothy N. Phoenix, Carl Koschmann, Frank Alvaro, Christopher V. Dayas, Christopher L. Tinkle, Helen Wheeler, James R. Whittle, David D. Eisenstat, Ron Firestein, Sabine Mueller, Santosh Valvi, Jordan R. Hansford, David M. Ashley, Simon G. Gregory, Lindsay B. Kilburn, Javad Nazarian, Jason E. Cain, Matthew D. Dun
Virtually all patients with BRAF-mutant melanoma develop resistance to MAPK inhibitors largely through non-mutational events. Although the epigenetic landscape is shown to be altered in therapy-resistant melanomas and other cancers, a specific targetable epigenetic mechanism has not been validated to date. Here, we evaluate the CoREST repressor complex and the recently developed bivalent inhibitor, corin, within the context of melanoma phenotype plasticity and therapeutic resistance. We find that CoREST is a critical mediator of the major distinct melanoma phenotypes and that corin treatment of melanoma cells leads to phenotype reprogramming. Global assessment of transcript and chromatin changes conferred by corin reveals specific effects on histone marks connected to EMT-associated transcription factors and the dual-specificity phosphatases (DUSPs). Remarkably, treatment of BRAF inhibitor (BRAFi)-resistant melanomas with corin promotes resensitization to BRAFi therapy. DUSP1 is consistently downregulated in BRAFi-resistant melanomas which is reversed by corin treatment and associated with inhibition of p38 MAPK activity and resensitization to BRAFi therapies. Moreover, this activity can be recapitulated by the p38 MAPK inhibitor, BIRB 796. These findings identify the CoREST repressor complex as a central mediator of melanoma phenotype plasticity and resistance to targeted therapy and suggest that CoREST inhibitors may prove beneficial to patients with BRAFi-resistant melanoma.
Muzhou Wu, Ailish Hanly, Frederick Gibson, Robert Fisher, Samantha Rogers, Kihyun Park, Angelina Zuger, Kevin Kuang, Jay H. Kalin, Sarah Nocco, Matthew Cole, Amy Xiao, Filisia Agus, Adam Labadorf, Samuel Beck, Marianne Collard, Philip A. Cole, Rhoda M. Alani
BACKGROUND. HER2-targeting therapies have great efficacy in HER2-positive breast cancer, but resistance in part due to HER2 heterogeneity (HET) is a significant clinical challenge. We previously described that in a phase II neoadjuvant trastuzumab emtansine (T-DM1) and pertuzumab (T-DM1+P) clinical trial in early-stage HER2-positive breast cancer, none of the patients with HER2-HET tumors had pathologic complete response (pCR). METHODS. To investigate cellular and molecular differences among tumors according to HER2 heterogeneity and pCR, we performed RNA sequencing (RNA-seq) and ERBB2 FISH of 285 pre/post-treatment tumors from 129 patients in this T-DM1+P neoadjuvant trial. A subset of cases was also subject to Nanostring spatial digital profiling. RESULTS. Pre-treatment tumors from patients with pCR had the highest level of ERBB2 mRNA and ERBB signaling. HET was associated with no pCR, basal-like features, low ERBB2 expression yet high ERBB signaling sustained by activation of downstream pathway components. Residual tumors showed decreased HER2 protein levels and ERBB2 copy number heterogeneity and increased PI3K pathway enrichment and luminal features. HET tumors showed minimal treatment-induced transcriptomic changes compared to non-HET tumors. Immune infiltration correlated with pCR and HER2-HET status. CONCLUSION. Resistance mechanisms in HET and non-HET tumors are distinct. HER2-targeting antibodies have limited efficacy in HET tumors. Our results support the stratification of patients based on HET status and the use of agents that target downstream components of the ERBB signaling pathway in patients with HET tumors. TRIAL REGISTRATION. Clinicaltrials.gov NCT02326974. FUNDING. This study was funded by Roche and the National Cancer Institute.
Zheqi Li, Otto Metzger Filho, Giuseppe Viale, Patrizia dell'Orto, Leila Russo, Marie-Anne Goyette, Avni Kamat, Denise A. Yardley, Vandana Gupta Abramson, Carlos L. Arteaga, Laura M. Spring, Kami Chiotti, Carol Halsey, Adrienne G. Waks, Tari A. King, Susan C. Lester, Jennifer R. Bellon, Eric P. Winer, Paul T. Spellman, Ian E. Krop, Kornelia Polyak
Stromal interaction molecule 1 (STIM1) is a Ca2+ sensor located in the sarcoplasmic reticulum (SR) of skeletal muscle where it is best known for its role in store operated Ca2+ entry (SOCE). Genetic syndromes resulting from STIM1 mutations are recognized as a cause of muscle weakness and atrophy. Here, we focus on a gain of function mutation that occurs in humans and mice (STIM1+/D84G mice) where muscles exhibit constitutive SOCE. Unexpectedly, this constitutive SOCE did not affect global Ca2+ transients, SR Ca2+ content or excitation contraction coupling (ECC) and was therefore unlikely to underlie the reduced muscle mass and weakness observed in these mice. Instead, we demonstrate that the presence of D84G STIM1 in the nuclear envelope disrupts nuclear-cytosolic coupling causing severe derangement in nuclear architecture of STIM1+/D84G muscle, DNA damage and altered lamina A associated gene expression. Functionally, we found D84G STIM1 reduced the transfer of Ca2+ from the cytosol to the nucleus in myoblasts resulting in a reduction of [Ca2+]N. Taken together, we propose a novel role for STIM1 in the nuclear envelope that links Ca2+ signaling to nuclear stability in skeletal muscle.
Victoria Bryson, Chaojian Wang, Zirui Zhou, Kavisha Singh, Noah M. Volin, Eda Yildirim, Paul Rosenberg
The measles, mumps and rubella (MMR) vaccine protects against all-cause mortality in children, but the immunological mechanisms mediating these effects are poorly known. We systematically investigated whether MMR can induce long-term functional changes in innate immune cells, a process termed trained immunity, that could at least partially mediate this heterologous protection. In a randomized placebo-controlled trial, 39 healthy adults received either the MMR vaccine or a placebo. By using single-cell RNA-sequencing, we found that MMR caused transcriptomic changes in CD14-positive monocytes and NK cells, but most profoundly in γδ T cells. Monocyte function was not altered by MMR vaccination. In contrast, the function of γδ T cells was markedly enhanced by MMR vaccination, with higher production of TNF and IFNγ, as well as upregulation of cellular metabolic pathways. In conclusion, we describe a trained immunity program characterized by modulation of γδ T cell function induced by MMR vaccination.
Rutger J. Röring, Priya A. Debisarun, Javier Botey-Bataller, Tsz Kin Suen, Ozlem Bulut, Gizem Kilic, Valerie A.C.M. Koeken, Andrei Sarlea, Harsh Bahrar, Helga Dijkstra, Heidi Lemmers, Katharina L. Gössling, Nadine Rüchel, Philipp N. Ostermann, Lisa Müller, Heiner Schaal, Ortwin Adams, Arndt Borkhardt, Yavuz Ariyurek, Emile J. de Meijer, Susan L. Kloet, Jaap ten Oever, Katarzyna Placek, Yang Li, Mihai G. Netea
In response to a meal, insulin drives hepatic glycogen synthesis to help regulate systemic glucose homeostasis. The mechanistic target of rapamycin complex 1 (mTORC1) is a well-established insulin target and contributes to the postprandial control of liver lipid metabolism, autophagy, and protein synthesis. However, its role in hepatic glucose metabolism is less understood. Here, we used metabolomics, isotope tracing, and mouse genetics to define a role for liver mTORC1 signaling in the control of postprandial glycolytic intermediates and glycogen deposition. We show that mTORC1 is required for glycogen synthase activity and glycogenesis. Mechanistically, hepatic mTORC1 activity promotes the feeding-dependent induction of Ppp1r3b, a gene encoding a phosphatase important for glycogen synthase activity whose polymorphisms are linked to human diabetes. Re-expression of Ppp1r3b in livers lacking mTORC1 signaling enhances glycogen synthase activity and restores postprandial glycogen content. mTORC1-dependent transcriptional control of Ppp1r3b is facilitated by FOXO1, a well characterized transcriptional regulator involved in the hepatic response to nutrient intake. Collectively, we identify a role for mTORC1 signaling in the transcriptional regulation of Ppp1r3b and the subsequent induction of postprandial hepatic glycogen synthesis.
Kahealani Uehara, Won Dong Lee, Megan Stefkovich, Dipsikha Biswas, Dominic Santoleri, Anna E. Garcia Whitlock, William J. Quinn III, Talia N. Coopersmith, Kate Townsend Creasy, Daniel J. Rader, Kei Sakamoto, Joshua D. Rabinowitz, Paul M. Titchenell
BACKGROUND. Malaria transmission blocking vaccines aim to interrupt the transmission of malaria from one person to another. METHODS. The candidates, R0.6C and ProC6C, share the Plasmodium falciparum sexual stage antigen, Pfs48/45 “6C” domain. R0.6C utilizes the Glutamate Rich Protein (GLURP) as a carrier and ProC6C includes a second domain (Pfs230-Pro) and a short 36 amino acids CSP sequence. Healthy adults (n = 125) from a malaria endemic area of Burkina Faso were immunized with three intramuscular injections, four weeks apart, of 30 μg or 100 μg R0.6C or ProC6C each adsorbed to Alhydrogel adjuvant (AlOH) alone or in combination with Matrix-M (15 μg or 50 μg, respectively). The allocation was random and double blind for this Phase 1 trial. RESULTS. The vaccines were safe and well tolerated with no vaccine-related serious adverse events. A total of seven adverse events, mild to moderate in intensity and considered possibly related to the study vaccines were recorded. Vaccine-specific antibodies were highest in volunteers immunized with 100 μg ProC6C-AlOH with Matrix-M, and 13/20 (65%) subjects in the group showed greater than 80% transmission reducing activity (TRA) when evaluated in the standard membrane feeding assay at 15 mg/mL IgG. In contrast, R0.6C induced sporadic TRA. CONCLUSIONS. All formulations were safe and well tolerated in a malaria endemic area of Africa in healthy adults. The ProC6C-AlOH/Matrix-M vaccine elicited the highest levels of functional antibodies, meriting further investigation. TRIAL REGISTRATION. Pactr.org PACTR202201848463189. FUNDING. The study was funded by the European Union and Developing Countries Clinical Trials Partnership (Grant number RIA2018SV-2311).
B. Alfred Tiono, Jordan L. Plieskatt, Alphonse Ouedraogo, Ben Idriss Soulama, Kazutoyo Miura, Edith C. Bougouma, Mohammad Naghizadeh, Aissata Barry, Jean Baptiste B. Yaro, Sem Ezinmegnon, Noelie B. Henry, Ebenezer Ofori, Bright Adu, Susheel K. Singh, Augustin Konkobo, Karin Lövgren Bengtsson, Amidou Diarra, Cecilia Carnrot, Jenny M. Reimer, Amidou Z. Ouedraogo, Moussa Tienta, Carole A. Long, Issa N. Nebie, Issaka Sagara, Sodiomon B. Sirima, Michael Theisen
Merkel cell carcinoma (MCC) is a highly immunogenic skin cancer primarily induced by Merkel Cell Polyomavirus, driven by the expression of the oncogenic T antigens (T-Ags). Blockade of the programmed cell death protein-1 (PD-1) pathway has shown remarkable response rates, but evidence for therapy-associated T-Ag-specific immune response and therapeutic strategies for the non-responding fraction are both limited. We tracked T-Ag-reactive CD8+ T cells in peripheral blood of 26 MCC patients under anti-PD1 therapy, using DNA-barcoded pMHC multimers, displaying all peptides from the predicted HLA ligandome of the oncoproteins, covering 33 class-I haplotypes. We observed a broad T-cell recognition of T-Ags, including identification of 20 novel T-Ag-derived epitopes. Broadening of the T-Ag recognition profile and increased T-cell frequencies during therapy were strongly associated with clinical response and prolonged progression-free survival. T-Ag-specific T cells could be further boosted and expanded directly from peripheral blood using artificial antigen-presenting scaffolds, even in patients with no detectable T-Ag-specific T cells. These T cells provided strong tumor rejection capacity while retaining a favorable phenotype for adoptive cell transfer. These findings demonstrate that T-Ag-specific T cells are associated with the clinical outcome to PD-1 blockade and that Ag-presenting scaffolds can be used to boost such responses.
Ulla Kring Hansen, Candice D. Church, Ana Micaela Carnaz Simões, Marcus Svensson Frej, Amalie Kai Bentzen, Siri A. Tvingsholm, Jürgen C. Becker, Steven P. Fling, Nirasha Ramchurren, Suzanne L. Topalian, Paul T. Nghiem, Sine Reker Hadrup
Virus-induced memory T cells often express functional cross-reactivity, or heterologous immunity, to other viruses and to allogeneic MHC molecules that is an important component of pathogenic responses to allogeneic transplants. During immune responses antigen-reactive naïve and central memory T cells proliferate in secondary lymphoid organs to achieve sufficient cell numbers to effectively respond whereas effector memory T cell proliferation occurs directly within the peripheral inflammatory microenvironment. Mechanisms driving heterologous memory T cell proliferation and effector function expression within peripheral tissues remain poorly understood. Here we dissected heterologous donor-reactive memory CD8 T cell proliferation and their effector functions following infiltration into heart allografts having low or high intensities of ischemic inflammation. Proliferation within both ischemic conditions requires p40 homodimer-induced IL-15 transpresentation by graft dendritic cells, but expression of effector functions mediating acute allograft injury occurs only in high-ischemic allografts. Transcriptional responses of heterologous donor-reactive memory CD8 T cells are distinct from donor antigen-primed memory CD8 T cells during early activation in allografts and at graft rejection. Overall, the results insights into mechanisms driving heterologous effector memory CD8 T cell proliferation and the separation between proliferation and effector function, that is dependent on the intensity of inflammation within the tissue microenvironment.
Hidetoshi Tsuda, Karen S. Keslar, William M. Baldwin III, Peter S. Heeger, Anna Valujskikh, Robert L. Fairchild
Loss of BRCA2 (BReast CAncer 2) is lethal for normal cells. Yet, it remains poorly understood how in BRCA2 mutation carriers, cells undergoing loss of heterozygosity overcome the lethality and undergo tissue-specific neoplastic transformation. Here, we identified mismatch repair gene, MLH1 as a genetic interactor of BRCA2 whose over-expression supports the viability of Brca2-null cells. Mechanistically, we showed that MLH1 interacts with Flap endonuclease 1 (FEN1) and competes to process the RNA flaps of Okazaki fragments. Together, they restrained the DNA2 nuclease activity on the reversed forks of lagging strands, leading to replication fork (RF) stability in BRCA2-deficient cells. In these cells, MLH1 also attenuated R-loops, allowing the progression of stable RFs, which suppressed the genomic instability and supported cell viability. We demonstrated the significance of their genetic interaction by the lethality of Brca2-mutant mice and inhibition of Brca2-deficient tumor growth in mice by Mlh1 loss. Furthermore, we described that estrogen induces MLH1 expression through estrogen receptor alpha (ERα), which might explain why the majority of BRCA2 mutation carriers develop ER positive breast cancer. Taken together, our findings reveal a role of MLH1 in relieving replicative stress and how it may contribute to the establishment of BRCA2-deficient breast tumors.
Satheesh K. Sengodan, Xiaoju Hu, Vaishnavi Peddibhotla, Kuppusamy Balamurugan, Alexander Y. Mitrophanov, Lois McKennett, Suhas S. Kharat, Rahul Sanawar, Vinod Kumar Singh, Mary E. Albaugh, Sandra S. Burkett, Yongmei Zhao, Bao Tran, Tyler Malys, Esta Sterneck, Subhajyoti De, Shyam K. Sharan
BACKGROUND. The tumor immune microenvironment can provide prognostic and therapeutic information. We aimed to develop noninvasive imaging biomarkers from computed tomography (CT) for comprehensive evaluation of immune context, and investigate their associations with prognosis and immunotherapy response in gastric cancer (GC). METHODS. This study involved 2,600 GC patients of nine independent cohorts. We developed and validated two CT imaging biomarkers [lymphoid radiomics score (LRS) and myeloid radiomics score (MRS)] for evaluating the immunohistochemistry (IHC)-derived lymphoid and myeloid immune context respectively, and then integrated them into a combined imaging biomarker [LRS/MRS: low(−) or high(+)] with four radiomics immune subtypes: 1(−/−), 2(+/−), 3(−/+), and 4(+/+). We further evaluated the imaging biomarkers' predictive values on prognosis and immunotherapy response. RESULTS. The developed imaging biomarkers (LRS and MRS) had a high accuracy in predicting lymphoid (AUC range: 0.765-0.773) and myeloid (AUC range: 0.736-0.750) immune context. Furthermore, same as IHC-derived immune context, two imaging biomarkers (HR range: 0.240-0.761 for LRS; 1.301-4.012 for MRS) and the combined biomarker were independent predictors for disease-free and overall survival in the training and all validation cohorts (all P<0.05). In addition, patient with high LRS or low MRS may benefit more from immunotherapy (P<0.001). Furthermore, a highly heterogeneous outcome on objective response rate was observed in four imaging subtypes: 1(−/−) with 27.3%, 2(+/−) with 53.3%, 3(−/+) with 10.2%, and 4(+/+) with 30.0% (P<0.0001). CONCLUSION. The noninvasive imaging biomarkers could accurately evaluate the immune context, and provide information regarding prognosis and immunotherapy for GC. FUNDING. None
Zepang Sun, Taojun Zhang, M. Usman Ahmad, Zixia Zhou, Liang Qiu, Kangneng Zhou, Wenjun Xiong, Jingjing Xie, Zhicheng Zhang, Chuanli Chen, Qingyu Yuan, Yan Chen, Wanying Feng, Yikai Xu, Lequan Yu, Wei Wang, Jiang Yu, Guoxin Li, Yuming Jiang
Maggie E. Jones-Carr, Huma Fatima, Vineeta Kumar, Douglas J. Anderson, Julie Houp, Jackson C. Perry, Gavin A. Baker, Leigh McManus, Andrew J. Shunk, Paige M. Porrett, Jayme E. Locke
Breast cancer stem cells (BCSCs) mitigate oxidative stress to maintain their viability and plasticity. However, the regulatory mechanism of oxidative stress in BCSCs remains unclear. We recently found that the histone reader ZMYND8 was upregulated in BCSCs. Here, we showed that ZMYND8 reduced ROS and iron to inhibit ferroptosis in aldehyde dehydrogenase (ALDH)high BCSCs, leading to BCSC expansion and tumor initiation in mice. The underlying mechanism involved a twofold posttranslational regulation of nuclear factor erythroid 2–related factor 2 (NRF2). ZMYND8 increased stability of NRF2 protein through KEAP1 silencing. On the other hand, ZMYND8 interacted with and recruited NRF2 to the promoters of antioxidant genes to enhance gene transcription in mammospheres. NRF2 phenocopied ZMYND8 to enhance BCSC stemness and tumor initiation by inhibiting ROS and ferroptosis. Loss of NRF2 counteracted ZMYND8’s effects on antioxidant genes and ROS in mammospheres. Interestingly, ZMYND8 expression was directly controlled by NRF2 in mammospheres. Collectively, these findings uncover a positive feedback loop that amplifies the antioxidant defense mechanism sustaining BCSC survival and stemness.
Maowu Luo, Lei Bao, Yuanyuan Xue, Ming Zhu, Ashwani Kumar, Chao Xing, Jennifer E Wang, Yingfei Wang, Weibo Luo
Ischemia reperfusion injury (IRI)-mediated primary graft dysfunction (PGD) adversely impacts both short- and long-term outcomes after lung transplantation, a procedure which remains the only treatment option for patients suffering from end-stage respiratory failure. While B cells are known to regulate adaptive immune responses, their role in lung IRI is not well understood. Here, we demonstrate by intravital imaging that B cells are rapidly recruited to injured lungs, where they extravasate into the parenchyma. Using hilar clamping and transplant models, we observe that lung-infiltrating B cells produce the monocyte chemokine CCL7 in Toll-like receptor 4 (TLR4)-TRIF-dependent fashion, a critical step contributing to classical monocyte (CM) recruitment and subsequent neutrophil extravasation, resulting in worse lung function. We find that synergistic BCR-TLR4 activation on B cells is required for the recruitment of CMs to the injured lung. Finally, we corroborate our findings in reperfused human lungs, where we observe a correlation between B cell infiltration and CM recruitment after transplantation. This study describes a role for B cells as critical orchestrators of lung IRI. As B cells can be depleted with currently available agents, our study provides a rationale for clinical trials investigating B cell-targeting therapies.
Khashayar Farahnak, Yun Zhu Bai, Yuhei Yokoyama, Deniz B. Morkan, Zhiyi Liu, Junedh M. Amrute, Alejandro De Filippis Falcon, Yuriko Terada, Fuyi Liao, Wenjun Li, Hailey M. Shepherd, Ramsey R. Hachem, Varun Puri, Kory J. Lavine, Andrew E. Gelman, Ankit Bharat, Daniel Kreisel, Ruben G. Nava
Wnts, cholesterol, and MAPK signaling are essential for development and adult homeostasis. Here we report for the first time that fatty acid hydroxylase domain containing 2 (FAXDC2), a previously uncharacterized enzyme, functions as a methyl sterol oxidase catalyzing C4 demethylation in the Kandutsch-Russell branch of the cholesterol biosynthesis pathway. FAXDC2, a paralog of MSMO1, regulates the abundance of specific C4-methyl sterols lophenol and dihydro-TMAS. Highlighting its clinical relevance, FAXDC2 is repressed in Wnt/β-catenin high cancer xenografts, in a mouse genetic model of Wnt activation, and in human colorectal cancers. Moreover, in primary human colorectal cancers, the sterol lophenol, regulated by FAXDC2, accumulates in the cancerous tissues and not in adjacent normal tissues. FAXDC2 links Wnts to RTK/MAPK signaling. Wnt inhibition drives increased recycling of RTKs and activation of the MAPK pathway, and this requires FAXDC2. Blocking Wnt signaling in Wnt-high cancers causes both differentiation and senescence; and this is prevented by knockout of FAXDC2. Our data shows the integration of three ancient pathways, Wnts, cholesterol synthesis, and RTK/MAPK signaling, in cellular proliferation and differentiation.
Babita Madan, Shawn R. Wadia, Siddhi Patnaik, Nathan Harmston, Emile K.W. Tan, Iain Bee Huat Tan, W. David Nes, Enrico Petretto, David M. Virshup