Fusion-negative rhabdomyosarcoma 3D organoids to predict effective drug combinations: A proof-of-concept on cell death inducers

Rhabdomyosarcoma (RMS) is the main form of pediatric soft-tissue sarcoma. Its cure rate has not notably improved in the last 20 years following relapse, and the lack of reliable preclinical models has hampered the design of new therapies. This is particularly true for highly heterogeneous fusion-negative RMS (FNRMS). Although methods have been proposed to establish FNRMS organoids, their efficiency remains limited to date, both in terms of derivation rate and ability to accurately mimic the original tumor. Here, we present the development of a next-generation 3D organoid model derived from relapsed adult and pediatric FNRMS. This model preserves the molecular features of the patients' tumors and is expandable for several months in 3D, reinforcing its interest to drug combination screening with longitudinal efficacy monitoring. As a proof-of-concept, we demonstrate its preclinical relevance by reevaluating the therapeutic opportunities of targeting apoptosis in FNRMS from a streamlined approach based on transcriptomic data exploitation.

Netrin-1 blockade inhibits tumour growth and EMT features in endometrial cancer

Netrin-1 is upregulated in cancers as a protumoural mechanism1. Here we describe netrin-1 upregulation in a majority of human endometrial carcinomas (ECs) and demonstrate that netrin-1 blockade, using an anti-netrin-1 antibody (NP137), is effective in reduction of tumour progression in an EC mouse model. We next examined the efficacy of NP137, as a first-in-class single agent, in a Phase I trial comprising 14 patients with advanced EC. As best response we observed 8 stable disease (8 out of 14, 57.1%) and 1 objective response as RECIST v.1.1 (partial response, 1 out of 14 (7.1%), 51.16% reduction in target lesions at 6 weeks and up to 54.65% reduction during the following 6 months). To evaluate the NP137 mechanism of action, mouse tumour gene profiling was performed, and we observed, in addition to cell death induction, that NP137 inhibited epithelial-to-mesenchymal transition (EMT). By performing bulk RNA sequencing (RNA-seq), spatial transcriptomics and single-cell RNA-seq on paired pre- and on-treatment biopsies from patients with EC from the NP137 trial, we noted a net reduction in tumour EMT. This was associated with changes in immune infiltrate and increased interactions between cancer cells and the tumour microenvironment. Given the importance of EMT in resistance to current standards of care2, we show in the EC mouse model that a combination of NP137 with carboplatin-paclitaxel outperformed carboplatin-paclitaxel alone. Our results identify netrin-1 blockade as a clinical strategy triggering both tumour debulking and EMT inhibition, thus potentially alleviating resistance to standard treatments.

The TLR3 L412F polymorphism prevents TLR3-mediated tumor cell death induction in pediatric sarcomas

Toll-like receptor 3 (TLR3) is a pattern recognition receptor mainly known for its role in innate immune response to infection. Indeed, binding of double-stranded RNA (dsRNA) to TLR3 triggers a pro-inflammatory cascade leading to cytokine release and immune cell activation. Its anti-tumoral potential has emerged progressively, associated with a direct impact on tumor cell death induction and with an indirect action on immune system reactivation. Accordingly, TLR3 agonists are currently being tested in clinical trials for several adult cancers. Meanwhile, TLR3 variants have been linked to auto-immune disorders, and as risk factors of viral infection and cancers. However, aside from neuroblastoma, TLR3 role in childhood cancers has not been evaluated. Here, by integrating public transcriptomic data of pediatric tumors, we unveil that high TLR3 expression is largely associated with a better prognosis in childhood sarcomas. Using osteosarcomas and rhabdomyosarcomas as models, we show that TLR3 efficiently drives tumor cell death in vitro and induces tumor regression in vivo. Interestingly, this anti-tumoral effect was lost in cells expressing the homozygous TLR3 L412F polymorphism, which is enriched in a rhabdomyosarcomas cohort. Thus, our results demonstrate the therapeutic potential associated with the targeting of TLR3 in pediatric sarcomas, but also the need to stratify patients eligible for this clinical approach with respect to the TLR3 variants expressed.

Epithelial-to-mesenchymal transition promotes immune escape by inducing CD70 in non-small cell lung cancer

INTRODUCTION

Epithelial-to-mesenchymal transition (EMT) is associated with tumor aggressiveness, drug resistance, and poor survival in non-small cell lung cancer (NSCLC) and other cancers. The identification of immune-checkpoint ligands (ICPLs) associated with NSCLCs that display a mesenchymal phenotype (mNSCLC) could help to define subgroups of patients who may benefit from treatment strategies using immunotherapy.

METHODS

We evaluated ICPL expression in silico in 130 NSCLC cell lines. In vitro, CRISPR/Cas9-mediated knockdown and lentiviral expression were used to assess the impact of ZEB1 expression on CD70. Gene expression profiles of lung cancer samples from the TCGA (n = 1018) and a dataset from MD Anderson Cancer Center (n = 275) were analyzed. Independent validation was performed by immunohistochemistry and targeted-RNA sequencing in 154 NSCLC whole sections, including a large cohort of pulmonary sarcomatoid carcinomas (SC, n = 55).

RESULTS

We uncover that the expression of CD70, a regulatory ligand from the tumor necrosis factor ligand family, is enriched in mNSCLC in vitro models. Mechanistically, the EMT-inducer ZEB1 impacted CD70 expression and fostered increased activity of the CD70 promoter. CD70 overexpression was also evidenced in mNSCLC patient tumor samples and was particularly enriched in SC, a lung cancer subtype associated with poor prognosis. In these tumors, CD70 expression was associated with decreased CD3⁺ and CD8⁺ T-cell infiltration and increased T-cell exhaustion markers.

CONCLUSION

Our results provide evidence on the pivotal roles of CD70 and ZEB1 in immune escape in mNSCLC, suggesting that EMT might promote cancer progression and metastasis by not only increasing cancer cell plasticity but also reprogramming the immune response in the local tumor microenvironment.

Regulatory T cells promote cancer immune-escape through integrin αvβ8-mediated TGF-β activation

Presence of TGFβ in the tumor microenvironment is one of the most relevant cancer immune-escape mechanisms. TGFβ is secreted in an inactive form, and its activation within the tumor may depend on different cell types and mechanisms than its production. Here we show in mouse melanoma and breast cancer models that regulatory T (Treg) cells expressing the β8 chain of αvβ8 integrin (Itgβ8) are the main cell type in the tumors that activates TGFβ, produced by the cancer cells and stored in the tumor micro-environment. Itgβ8 ablation in Treg cells impairs TGFβ signalling in intra-tumoral T lymphocytes but not in the tumor draining lymph nodes. Successively, the effector function of tumor infiltrating CD8+ T lymphocytes strengthens, leading to efficient control of tumor growth. In cancer patients, anti-Itgβ8 antibody treatment elicits similar improved cytotoxic T cell activation. Thus, this study reveals that Treg cells work in concert with cancer cells to produce bioactive-TGFβ and to create an immunosuppressive micro-environment.

Lipoic acid decreases breast cancer cell proliferation by inhibiting IGF-1R via furin downregulation

BACKGROUND

Breast cancer is the second most common cancer in the world. Despite advances in therapies, the mechanisms of resistance remain the underlying cause of morbidity and mortality. Lipoic acid (LA) is an antioxidant and essential cofactor in oxidative metabolism. Its potential therapeutic effects have been well documented, but its mechanisms of action (MOA) are not fully understood.

METHODS

The aim of this study is to validate the inhibitory LA effect on the proliferation of various breast cancer cell lines and to investigate the MOA that may be involved in this process. We tested LA effects by ex vivo studies on fresh human mammary tumour samples.

RESULTS

We demonstrate that LA inhibits the proliferation and Akt and ERK signalling pathways of several breast cancer cells. While searching for upstream dysregulations, we discovered the loss of expression of IGF-1R upon exposure to LA. This decrease is due to the downregulation of the convertase, furin, which is implicated in the maturation of IGF-1R. Moreover, ex vivo studies on human tumour samples showed that LA significantly decreases the expression of the proliferation marker Ki67.

CONCLUSION

LA exerts its anti-proliferative effect by inhibiting the maturation of IGF-1R via the downregulation of furin.

Integrated analysis highlights APC11 protein expression as a likely new independent predictive marker for colorectal cancer

After a diagnosis of colorectal cancer (CRC), approximately 50% of patients will present distant metastasis. Although significant progress has been made in treatments, most of them will die from the disease. We investigated the predictive and prognostic potential of APC11, the catalytic subunit of APC/C, which has never been examined in the context of CRC. The expression of APC11 was assessed in CRC cell lines, in tissue microarrays (TMAs) and in public datasets. Overexpression of APC11 mRNA was associated with chromosomal instability, lymphovascular invasion and residual tumor. Regression models accounting for the effects of well-known protein markers highlighted association of APC11 protein expression with residual tumor (odds ratio: OR = 6.51; 95% confidence intervals: CI = 1.54–27.59; P = 0.012) and metastasis at diagnosis (OR = 3.87; 95% CI = 1.20–2.45; P = 0.024). Overexpression of APC11 protein was also associated with worse distant relapse-free survival (hazard ratio: HR = 2.60; 95% CI = 1.26–5.37; P = 0.01) and worse overall survival (HR = 2.69; 95% CI = 1.31–5.51; P = 0.007). APC11 overexpression in primary CRC thus represents a potentially novel theranostic marker of metastatic CRC.

Targeting netrin-1/DCC interaction in diffuse large B-cell and mantle cell lymphomas

DCC (Deleted in Colorectal Carcinoma) has been demonstrated to constrain tumor progression by inducing apoptosis unless engaged by its ligand netrin‐1. This has been shown in breast and colorectal cancers; however, this tumor suppressive function in other cancers is not established. Using a transgenic mouse model, we report here that inhibition of DCC‐induced apoptosis is associated with lymphomagenesis. In human diffuse large B‐cell lymphoma (DLBCL), an imbalance of the netrin‐1/DCC ratio suggests a loss of DCC‐induced apoptosis, either via a decrease in DCC expression in germinal center subtype or by up‐regulation of netrin‐1 in activated B‐cell (ABC) one. Such imbalance is also observed in mantle cell lymphoma (MCL). Using a netrin‐1 interfering antibody, we demonstrate both in vitro and in vivo that netrin‐1 acts as a survival factor for ABC‐DLBCL and MCL tumor cells. Together, these data suggest that interference with the netrin‐1/DCC interaction could represent a promising therapeutic strategy in netrin‐1‐positive DLBCL and MCL.

[Variation of thermohaline properties in the Nicoya Gulf, Costa Rica]

The time-space behavior of thermohaline properties of the water masses in the Gulf of Nicoya, a tropical estuary in the Costa Rican Pacific coast, was studied by sampling monthly from April 1992 to April 1993. The saline field has a seasonal maximum during April, a month before the maximum temperature is observed. Minimun values were observed during October and November, in the rainy season. A defined surface saline front is located towards the east of Negritos Islands; it is produced by the interaction of freshwater from the Tarcoles River and the oceanic waters that enter through the occidental coast of the gulf. The vertical distribution of temperature and salinity indicates a gulf whose internal area is highly stratified in the rainy season, and much less stratified, or even well mixed in the dry season. The outer area of the Gulf is stratified throughout the year.

Metabolic changes associated with cluster root development in white lupin (Lupinus albus L.): relationship between organic acid excretion, sucrose metabolism and energy status

Under phosphorous deficiency, plants of white lupin (Lupinus albus L.) develop root clusters, which are also called proteoid roots due to their preferential presence in the Proteaceae. In their mature stage, these roots acidify the soil and excrete high amounts of carboxylates [up to 1.5 and 7 micromol (g FW)(-1) h(-1) of malate and citrate, respectively] enabling lupins to utilise sparingly available sources of phosphate. Using the amplified fragment length polymorphism (AFLP) technique, we identified genes predominantly expressed in juvenile and mature cluster roots. Transcripts for two enzymes involved in glycolysis, fructokinase and phosphoglucomutase, were identified in juvenile cluster roots and one, sucrose synthase, in mature cluster roots. In order to verify these observations we performed quantitative reverse transcription-polymerase chain reaction (RT-PCR) and could confirm the increased transcript level. Measurements of enzymatic activities showed that fructokinase and phosphoglucomutase activities increased in juvenile cluster roots, whereas sucrose synthase activity was maximal in mature cluster roots. These results indicate that formation of proteoid roots and citrate excretion increase sink strength locally. Production of citrate and inhibition of respiration are likely to result in an increased NADH/NAD+ ratio, which may be toxic for the plant. The fermentation pathway would allow oxidation of NADH by decarboxylation of pyruvate and subsequent reduction of the resulting acetaldehyde. Determination of alcohol dehydrogenase activity showed that this enzyme is strongly induced in mature proteoid roots. However, ethanol production was not increased, indicating that pyruvate is shunted to citrate synthesis and not to ethanol production.

[HL-A system in psoriasis; study of 31 families (author's transl)]

31 families with at least two psoriatic members, including sometimes three generations (4 families) have been studied looking for HL-A markers. They include 80 affected (45 females, 35 males) and 75 healthy persons. BW 17 has been found present in 58 p. 100 of the unrelated patients, versus 7 p. 100 only in the normal population (p less than 10-9). Relative risk (R.R.) for the people bearing BW 17 is 38.34. Increase of B 13 is slight and non significant. BW 16, BW 37, BW 27 are within normal range. B 12 (R.R. :0.36) seems to have a protecting effect. B 8, B 14 are also decreased. Study of way of genetic transmission favours existence of a dominant gene of susceptibility frequently associated with BW 17 and particularly with haplotype A 1, BW 17. But other genetic or environmental factors may also play a role.

[Immunological demonstration of large quantities of glycogen or of a glycogen-like substance in human embryonic colon cells and in colon carcinomas by means of rabbit antisera raised against a strain of Escherichia coli 013]

Rabbit antisera raised against a strain of E. coli 013, with a strong antiglycogen activity, were tested on human fetal and normal adult colons, on colon carcinomas, and on colon tumor cells in culture (HT29). Only very rare granules were present in adult normal colons when tested with the immunofluorescence method. In faetal colons, in 12 out of 14 carcinomas, and on HT29 cells, the immunofluorescent reactions were similar to those observed in normal liver. The reactions were negative after previous treatment with alpha-amylase. They were inhibited with glycogen, with phenol-alcohol, perchloric, and trichloroacetic extracts from faetal colons, and with a tumor trichloroacetic extract. The extracts precipitated with anti-E. coli 013 antisera. They had a strong inhibiting activity in a radioimmunoassay test with labeled glycogen. The extracts from normal adult colons did not precipitate with the antisera and they had no inhibiting activity in either immunofluorescence and radioimmunoassay tests.

[Antiglycogen activity of rabbit antisera raised against a strain of Escherichia coli 013]

Rabbit antisera raised against a strain of E. coli 013 (Su 4321/41 013 K11 H11) contain high titres of antiglycogen antibodies. This activity was evidenced through positive immunofluorescent reactions observed on liver and muscle sections. Such reactions disappeared when the sections were previously treated with alpha-amylase. They were inhibited with Oyster glycogen, phenolalcohol, perchloric acid, and trichloroacetic liver extracts. These same substances had no inhibiting activity when treated with alpha-amylase. The immunofluorescent reactions were negative on livers from Mice treated with endotoxins and insulin which are known to deplete the stores of liver glycogen. The antisera gave interfacial precipitates with glycogen and liver extracts. The same substances, as well as the LPS from E. coli 013, had a specific inhibiting activity in a radioimmunoassay test using glycogen linked to bovine serumalbumine labeled with 125I.

[Antigenic and immunogenic activities of dog spleen dry acetone powder for DLA histocompatibility test system]

The specific lymphocytotoxic activity of an anti DLA-A 9 serum was completely removed when absorbed with spleen dry acetone powder from a DLA-A 9 dog, but was not modified when absorbed with spleen powder from a non DLA-A 9 dog. A lymphocytotoxic serum specific for DLA-B 13 was produced in a dog injected with spleen dry acetone powder from a DLA-B 13 dog.