Abstract 2647: RVU120, a selective CDK8/CDK19 inhibitor, demonstrates efficacy against hormone-independent breast cancer cells in vitro and in vivo

Breast cancer (BC) is a complex and heterogenous disease, and various approaches have been used to classify BC into several subtypes to improve diagnostic and therapeutic outcomes. One of the features of BC is deregulated transcription, which allows for classification of the disease based on gene expression signature into four basic types: Luminal A, Luminal B, HER2-enriched, and triple negative (TNBC)/basal-like. Novel therapeutic approaches targeting oncogenic transcriptional programs may represent a promising strategy, in particular for TNBC, where the lack of common genetic alterations has so far limited the development of targeted therapies.

The CDK8 module functions as a master coordinator of transcription, bridging enhancers and core promoters. Meta-analysis of curated TCGA data reveals that >15% of all BC have increased expression of CDK8 and/or CDK19, and that elevated expression of both genes is associated with decreased overall survival. High CDK8 expression is inversely correlated with the expression of estrogen receptor (ER) and positively correlated with occurrence of TP53 mutations.

RVU120 is a specific, low nM, selective inhibitor of CDK8/CDK19, currently being tested in a first-in-human Phase Ib clinical trial in patients with metastatic or advanced solid tumors progressing from previous lines of therapy (ClinicalTrials.gov: NCT05052255).

In order to establish a rationale for treatment of BC with RVU120 we have interrogated a panel of cell lines representing various subtypes of BC. These studies revealed that TNBC and ER-/PR-/HER2+ cells were highly sensitive to RVU120 and also to two other non-related CDK8/19 inhibitors, indicating a class effect. In contrast, CDK8/19 inhibitors were not able to inhibit mitogenic effect of estrogen, confirming differential efficacy in hormone - independent BC.

Detailed transcriptional profiling of RVU120-responder cells revealed high enrichment of STAT3 target genes, SOX4 target genes and gene hallmarks of epithelial to mesenchymal transition (EMT), signatures associated with invasiveness and stemness. Non-responder cells were characterized by enrichment of transcriptional signatures of ER activity. Further proteomic profiling show that the top responder cells were the Mesenchymal Stem-Like (MSL) molecular subtype of TNBC and were positive for transactivated pSTAT3. Transcriptomic RNAseq profiling of MSL TNBC cell lines indicated that among genes inhibited by RVU120 there was high enrichment of STAT1 (interferon signature), STAT3 (IL6- signaling) and STAT5 (IL2 signaling) dependent genes. Single agent efficacy of RVU120 has been confirmed in subcutaneous TNBC xenograft models in vivo at well tolerated doses. Overall, these studies provide rationale for further development of RVU120 in TNBC patients.

Citation Format: Urszula Pakulska, Marta Obacz, Aniela Gołas, Milena Mazan, Magdalena Masiejczyk, Agata Stachowicz, Justyna Martyka, Michał Combik, Kinga Kęska, Katarzyna Wiklik, Kristina Goller, Elżbieta Adamczyk, Krzysztof Brzózka, Tomasz Rzymski. RVU120, a selective CDK8/CDK19 inhibitor, demonstrates efficacy against hormone-independent breast cancer cells in vitro and in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2647.

Abstract P5-17-13: Selective CDK8/CDK19 inhibitor RVU120 demonstrates efficacy against hormone-independent breast cancer cells in vitro and in vivo

Breast cancer (BC) is a complex and heterogenous disease, and various approaches have been used to classify BC into several subtypes to improve diagnostic and therapeutic outcomes. One of the features of BC is deregulated transcription, which allows for classification of the disease based on gene expression signature into four basic types: Luminal A, Luminal B, HER2-enriched, and triple negative (TNBC)/basal-like. Novel therapeutic approaches targeting oncogenic transcriptional programs may represent a promising strategy, in particular for TNBC, where the lack of common genetic alterations has so far limited the development of targeted therapies. The CDK8 module of the mediator complex represents an effective therapeutic target across multiple hematologic malignancies and solid tumors. CDK8 module of mediator functions as a master coordinator of transcription, bridging enhancers and core promoters. Meta-analysis of transcriptomic data revealed that higher CDK8 expression and its paralog CDK19 is associated with shorter relapse-free survival (RFS) in all molecular subtypes of BC. Our analysis of curated TCGA data revealed that >15% of all BC have alterations in either CDK8 or CDK19. Increased expression of CDK8 in BC can be partially attributed to copy number gains and amplifications. High CDK8 expression was inversely correlated with the expression of estrogen receptor (ER) and positively correlated with occurrence of TP53 mutations. In order to identify whether increased expression of CDK8/19 in BC could be associated with increased sensitivity to pharmacological inhibition of both kinases, we have interrogated a panel of BC cell lines representing various subtypes with RVU120 - a specific, selective inhibitor of CDK8/CDK19, currently being tested in a first-in-human Phase Ib clinical trial. The highest sensitivity to RVU120 in clonogenic assays has been observed for TNBC and ER-/PR-/HER2+ cells with high STAT3 phosphorylation levels. In contrast, neither RVU120 nor other CDK8 inhibitors were able to inhibit mitogenic effect of estrogen, confirming differential efficacy in hormone - independent BC. Detailed transcriptional profiling of responder cells revealed high enrichment of TNF/NFKB and STAT target genes (signatures associated with inflammatory phenotypes) and SOX4 target genes (signatures associated with invasiveness and stemness). Non-responder cells were characterized by enrichment of transcriptional signatures of ER activity. Efficacy of RVU120 in TNBC cells has been corroborated in a three-dimensional (3D) spheroid viability assay that could predict in vivo efficacy of RVU120 in tested xenograft models and recapitulated using other chemically non-related CDK8 inhibitors, indicating a class effect. Single agent efficacy of RVU120 has been confirmed in subcutaneous TNBC xenograft models in vivo at well tolerated doses. These studies provide rationale for further development of RVU120 in TNBC patients.

Citation Format: Tomasz Rzymski, Aniela Gołas, Milena Mazan, Urszula Pakulska, Magdalena Masiejczyk, Agata Stachowicz, Justyna Martyka, Michał Combik, Katarzyna Wiklik, Kristina Goller, Marta Obacz, Elżbieta Adamczyk, Krzysztof Brzózka. Selective CDK8/CDK19 inhibitor RVU120 demonstrates efficacy against hormone-independent breast cancer cells in vitro and in vivo [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-17-13.

Abstract A78: Pre-existing, poly-resistant cancer stem cells in high-grade serous ovarian cancer

High-grade serous ovarian carcinoma (HGSOC) is the most common and lethal form of epithelial ovarian cancer. While HGSOCs respond well to platinum and taxane chemotherapy, the majority of patients eventually relapse with treatment-resistant tumors. This new and ominous resistance property of recurrent tumors is generally thought to be acquired in a process aided by the mutagenic activities of the chemotherapy itself. However, using advanced and robust technology that enables the direct cloning of cancer stem cells (CSCs) from HGSOCs, our study challenges the notion that chemotherapy resistance is acquired. In particular, patient-specific “libraries” of CSCs generated from therapy-naive tumors show that, while the majority of the CSCs are rapidly killed by platinum-taxane treatment, a discrete subset is highly resistant to these drugs to which they had no prior exposure. More telling is that these pre-existing, platinum-taxane resistant CSCs also display a profound “polyresistance” to a wide range of unrelated chemotherapeutic drugs. Importantly, gene expression profiles of polyresistant CSCs are highly uniform within a particular patient and clearly distinct from those of sensitive clones. This finding suggests that resistant clones within a patient carry the same gene signature, suggesting that resistance is a singular and knowable event in each patient. Comparing the resistance gene expression signatures across patients is revealing a very limited set of common pathways involving nuclear receptors that likely hold the key to the polyresistance phenomena. Taken together, our study supports the concept that these poly-resistant variants exist and can be cloned from most if not all HGOC patients. Further, the cloning of these polyresistant cells sets in motion the possibility that such variants can be exploited to identify both key pathways of polyresistance and drugs that specifically and pre-emptively eliminate these clones to prevent onset of recurrent disease.

Citation Format: Jingzhong Xie, Yusuke Yamamoto, Audrey-Ann Liew, Bailiang Wang, Rajasekaran Mahalingam, Marcin Duleba, Wei Rao, Suchan Niroula, Kristina Goller, Yanting Zhang, Shan Wang, Amir Jazaeri, Peter Davies, Suzy Torti, Giulio Draetta, Matthew Anderson, Molly Brewer, Christopher Crum, Frank McKeon, Wa Xian. Pre-existing, poly-resistant cancer stem cells in high-grade serous ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr A78.

Regenerative Metaplastic Clones in COPD Lung Drive Inflammation and Fibrosis

Chronic obstructive pulmonary disease (COPD) is a progressive condition of chronic bronchitis, small airway obstruction, and emphysema that represents a leading cause of death worldwide. While inflammation, fibrosis, mucus hypersecretion, and metaplastic epithelial lesions are hallmarks of this disease, their origins and dependent relationships remain unclear. Here we apply single-cell cloning technologies to lung tissue of patients with and without COPD. Unlike control lungs, which were dominated by normal distal airway progenitor cells, COPD lungs were inundated by three variant progenitors epigenetically committed to distinct metaplastic lesions. When transplanted to immunodeficient mice, these variant clones induced pathology akin to the mucous and squamous metaplasia, neutrophilic inflammation, and fibrosis seen in COPD. Remarkably, similar variants pre-exist as minor constituents of control and fetal lung and conceivably act in normal processes of immune surveillance. However, these same variants likely catalyze the pathologic and progressive features of COPD when expanded to high numbers.

Cloning of ground-state intestinal stem cells from endoscopic biopsy samples

'Adult' or 'somatic' stem cells harbor an intrinsic ability to regenerate tissues. Heterogeneity of such stem cells along the gastrointestinal tract yields the known segmental specificity of this organ and may contribute to the pathology of certain enteric conditions. Here we detail technology for the generation of 'libraries' of clonogenic cells from 1-mm-diamter endoscopic biopsy samples from the human gastrointestinal tract. Each of the 150-300 independent clones in a typical stem cell library can be clonally expanded to billions of cells in a few weeks while maintaining genomic stability and the ability to undergo multipotent differentiation to the specific epithelia from which the sample originated. The key to this methodology is the intrinsic immortality of normal intestinal stem cells (ISCs) and culture systems that maintain them as highly immature, ground-state ISCs marked by a single-cell clonogenicity of 70% and a corresponding 250-fold proliferative advantage over spheroid technologies. Clonal approaches such as this enhance the resolution of molecular genetics, make genome editing easier, and may be useful in regenerative medicine, unravelling heterogeneity in disease, and facilitating drug discovery.

Aberrant expression of embryonic mesendoderm factor MESP1 promotes tumorigenesis

Background

Mesoderm Posterior 1 (MESP1) belongs to the family of basic helix-loop-helix transcription factors. It is a master regulator of mesendoderm development, leading to formation of organs such as heart and lung. However, its role in adult pathophysiology remains unknown. Here, we report for the first time a previously-unknown association of MESP1 with non-small cell lung cancer (NSCLC).

Methods

MESP1 mRNA and protein levels were measured in NSCLC-derived cells by qPCR and immunoblotting respectively. Colony formation assay, colorimetric cell proliferation assay and soft agar colony formation assays were used to assess the effects of MESP1 knockdown and overexpression in vitro. RNA-sequencing and chromatin immunoprecipitation (ChIP)-qPCR were used to determine direct target genes of MESP1. Subcutaneous injection of MESP1-depleted NSCLC cells in immuno-compromised mice was done to study the effects of MESP1 mediated tumor formation in vivo.

Findings

We found that MESP1 expression correlates with poor prognosis in NSCLC patients, and is critical for proliferation and survival of NSCLC-derived cells, thus implicating MESP1 as a lung cancer oncogene. Ectopic MESP1 expression cooperates with loss of tumor suppressor ARF to transform murine fibroblasts. Xenografts from MESP1-depleted cells showed decreased tumor growth in vivo. Global transcriptome analysis revealed a MESP1 DNA-binding-dependent gene signature associated with various hallmarks of cancer, suggesting that transcription activity of MESP1 is most likely responsible for its oncogenic abilities.

Interpretation

Our study demonstrates MESP1 as a previously-unknown lineage-survival oncogene in NSCLC which may serve as a potential prognostic marker and therapeutic target for lung cancer in the future.

A multidimensional blood stimulation assay reveals immune alterations underlying systemic juvenile idiopathic arthritis

The etiology of autoinflammation in systemic juvenile idiopathic arthritis is unclear. Cepika et al. use integrated analysis of multidimensional blood stimulation data, applied to patients while off treatment and in complete remission, to reveal underlying cellular and molecular mechanisms that might predispose to disease.

The etiology of sporadic human chronic inflammatory diseases remains mostly unknown. To fill this gap, we developed a strategy that simultaneously integrates blood leukocyte responses to innate stimuli at the transcriptional, cellular, and secreted protein levels. When applied to systemic juvenile idiopathic arthritis (sJIA), an autoinflammatory disease of unknown etiology, this approach identified gene sets associated with specific cytokine environments and activated leukocyte subsets. During disease remission and off treatment, sJIA patients displayed dysregulated responses to TLR4, TLR8, and TLR7 stimulation. Isolated sJIA monocytes underexpressed the IL-1 inhibitor aryl hydrocarbon receptor (AHR) at baseline and accumulated higher levels of intracellular IL-1β after stimulation. Supporting the demonstration that AHR down-regulation skews monocytes toward macrophage differentiation, sJIA monocytes differentiated in vitro toward macrophages, away from the dendritic cell phenotype. This might contribute to the increased incidence of macrophage activation syndrome in these patients. Integrated analysis of high-dimensional data can thus unravel immune alterations predisposing to complex inflammatory diseases.

Human CD1c+ dendritic cells drive the differentiation of CD103+ CD8+ mucosal effector T cells via the cytokine TGF-β

In comparison to murine dendritic cells (DCs), less is known about the function of human DCs in tissues. Here, we analyzed, by using lung tissues from humans and humanized mice, the role of human CD1c(+) and CD141(+) DCs in determining the type of CD8(+) T cell immunity generated to live-attenuated influenza virus (LAIV) vaccine. We found that both lung DC subsets acquired influenza antigens in vivo and expanded specific cytotoxic CD8(+) T cells in vitro. However, lung-tissue-resident CD1c(+) DCs, but not CD141(+) DCs, were able to drive CD103 expression on CD8(+) T cells and promoted CD8(+) T cell accumulation in lung epithelia in vitro and in vivo. CD1c(+) DCs induction of CD103 expression was dependent on membrane-bound cytokine TGF-β1. Thus, CD1c(+) and CD141(+) DCs generate CD8(+) T cells with different properties, and CD1c(+) DCs specialize in the regulation of mucosal CD8(+) T cells.

Long-term outcome after coil embolization of cavernous sinus arteriovenous fistulas

BACKGROUND AND PURPOSE

Cranial nerve palsies are regularly observed in patients with arteriovenous fistulas of the cavernous sinus. The purpose of our study was to determine the long-term clinical outcome-with a special focus on extra-ocular muscular dysfunctions-in patients who had undergone endovascular treatment of a cavernous sinus fistula with detachable coils.

MATERIALS AND METHODS

Sixteen patients were recalled for an ophthalmoneurologic control examination (mean interval of 4.4 years). The mRS and the EQ-5D questionnaire were used for the description of general outcome. Age, duration of symptoms, character of the fistula (direct, dural), and coil volume were tested to assess their relevance for persistent symptoms.

RESULTS

All patients displayed complete regression of chemosis, exophthalmus, and pulsating tinnitus with no evidence of recurrences. Oculomotor disturbances persisted in 9 of 13 patients and caused permanent diplopia in 7 patients. In 15 patients a mRS score of 1 or 2 was achieved; however, 7 patients reported some limitations in life quality (EQ-5D). A significant correlation was found between coil volume and persistent diplopia (P = .032) and persistent cranial nerve VI paresis (P = .037).

CONCLUSIONS

Coil embolization of the cavernous sinus led to durable closure of AVF and reliable regression of acute symptoms. However, long-term follow-up showed a 44% rate of persistent cranial nerve deficits with disturbances of oculomotor and visual functions. This may be explained by the underlying fistula size itself and/or the space-occupying effect of the coils. As neuro-ophthalmologic outcome is crucial for control of therapeutic success, patients should be routinely examined by ophthalmologists.

Gabapentin is Effective in the Treatment of Cancer-Related Neuropathic Pain: A Prospective, Open-Label Studya,b

BACKGROUND

Gabapentin has been evaluated in the treatment of nonmalignant neuropathic pain, however, there is little direct evidence evaluating its efficacy in cancer-related neuropathic pain.

OBJECTIVE

This study evaluated the effectiveness of gabapentin to treat cancer-related neuropathic pain.

DESIGN

This was an open-label study. Two parallel groups of patients were recruited with either treatment-related (radiotherapy, surgery, chemotherapy) or tumor-related neuropathic pain. Gabapentin was dose-escalated from 300 mg/d to 1.8 g/d.

MEASUREMENTS

The primary outcome, pain, was assessed using the modified brief pain inventory. In addition patient descriptors of pain and scores of activities of daily living were collated together with demographic data.

RESULTS

We recruited 62 patients with treatment-related (n = 25) or tumor-related (n = 37) neuropathic pain. There was a significant reduction in the worst, average, and current pain scores (p < 0.002), but not the least pain score (p = 0.21). Twenty-eight of 62 (45.2%) of patients achieved at least a one third reduction in pain score (95% confidence interval [CI] 32.5-58.3); the number needed to treat to obtain this benefit is 2.2 (95% CI 1.7-3.1). There was a significant reduction in all scores measuring the impact of pain on daily living (p < 0.003). There was no significant difference in pain scores at day 8 compared to day 15. Analysis of variance suggested that gender, but not etiology, or type of neuropathic pain, was a significant predictor of analgesic response and this warrants further investigation.

CONCLUSION

We conclude that gabapentin is an effective treatment for cancer-related neuropathic pain.

Clinical response to morphine in cancer patients and genetic variation in candidate genes

Morphine is the analgesic of choice for moderate to severe cancer pain; however, 10-30% of patients do not tolerate morphine. This study evaluated genetic variation in the mu-opioid receptor, betaarrestin2, stat6 and uridine diphosphate-glucuronysltransferase 2B7 (UGT2B7) genes, in patients who responded to morphine vs those who were switched to alternative opioids. We prospectively recruited and genotyped 162 Caucasian patients (117 controls, 39 switchers). Switchers, were more likely to carry the common allele at 1182 G/A, 5864 G/A, 8622T/C and 11143 G/A in the betaarrestin2 gene (P = 0.021, 0.043, 0.013, 0.043, respectively). Switchers had increased carriage of the T allele (-1714 C/T) and a significant difference in the allelic frequency at 9065 C/T (chi(2) = 3.86, P = 0.049) in the stat6 gene. No differences were seen in genotype or allele frequencies of SNPs in the mu-opioid receptor gene or UGT2B7 gene. This study presents novel data suggesting that variation in genes involved in mu-opioid receptor signalling influence clinical response to morphine.

Far-infrared bandpass filters from perforated metal screens

Precision nickel printing screens are shown to be very useful as far-infrared bandpass filters. For a range of such regularly perforated sheets, transmission peaks of ~ 0.9 have been observed to lie at frequencies between 60 and 140 cm(-1). We found that this value shows little degradation by cascading several screens, but the overall filter Q value may be increased from 2.7 to a value of ~ 6. These screens have considerable advantages over conventional far-infrared bandpass filters in terms of strength, optical characteristics, and cost.