Clinical utility of comprehensive liquid molecular profiling in patients with advanced endometrial cancer.

BACKGROUND: Molecular characterization has significantly improved the management of advanced endometrial cancer (EC). It distinguishes four molecular subclasses associated with prognosis and personalized therapeutic strategies. This study assesses the clinical utility of cell-free DNA (cfDNA) profiling in EC to identify targetable alterations. METHODS: Women with metastatic or recurrent EC were prospectively recruited within the framework of the STING trial (NCT04932525), during which cfDNA was analyzed. Genomic alterations were identified with the FoundationOne CDx assay. Each molecular report underwent review by a molecular tumor board. Alterations were categorized via the European Society of Medical Oncology Scale for Clinical Actionability of Molecular Targets (ESCAT). RESULTS: A total of 61 patients were enrolled. The median age was 66.9 years, with 43% presenting frontline metastatic disease. All histologic subgroups were represented. Notably, 89% of patients yielded informative cfDNA analysis. Six tumors were classified with deficient mismatch repair/microsatellite instability (11%) and 37 as TP53 gene mutant (67%), and 12 had nonspecific molecular profiles (22%). Molecular classification based on liquid biopsy showed 87.5% accuracy in correlating with tissue results. Moreover, 65% of cases exhibited ≥1 actionable alteration, including 25% ESCAT I alterations and 13% ESCAT II alterations. Consequently, 16% of patients received a molecularly matched therapy, and presented with a 56% response rate and median progression-free survival of 7.7 months. CONCLUSIONS: cfDNA sequencing in EC is a feasible approach that produces informative results in 89% of cases and accurately categorizes patients into the main molecular subclasses. It also reveals multiple actionable alterations, which offers the potential for personalized therapeutic strategies.

[Current post-surgical treatment strategies in first-line ovarian cancer]. / Stratégies thérapeutiques post-chirurgicales actuelles dans les cancers de l'ovaire en première ligne de traitement.

Although the management of epithelial ovarian cancer has evolved significantly over the past few years, it remains a public health issue, as most patients are diagnosed at an advanced stage and relapse after first line treatment. Chemotherapy remains the standard adjuvant treatment for International Federation of Gynecology and Obstetrics (FIGO) stage I and II tumors, with some exceptions. For FIGO stage III/IV tumors, carboplatin- and paclitaxel-based chemotherapy are the standard of care, in combination with targeted therapies, especially bevacizumab and/or poly-(ADP-ribose) polymerase inhibitors, that have become a key milestone of first-line treatment. Our decision making for the maintenance therapy is based on the FIGO stage, tumor histology, timing of surgery (i.e. primary or interval debulking surgery), residual tumor, response to chemotherapy, BRCA mutation and homologous recombination (HR) status.

APR-246 increases tumor antigenicity independent of p53.

We previously reported that activation of p53 by APR-246 reprograms tumor-associated macrophages to overcome immune checkpoint blockade resistance. Here, we demonstrate that APR-246 and its active moiety, methylene quinuclidinone (MQ) can enhance the immunogenicity of tumor cells directly. MQ treatment of murine B16F10 melanoma cells promoted activation of melanoma-specific CD8+ T cells and increased the efficacy of a tumor cell vaccine using MQ-treated cells even when the B16F10 cells lacked p53. We then designed a novel combination of APR-246 with the TLR-4 agonist, monophosphoryl lipid A, and a CD40 agonist to further enhance these immunogenic effects and demonstrated a significant antitumor response. We propose that the immunogenic effect of MQ can be linked to its thiol-reactive alkylating ability as we observed similar immunogenic effects with the broad-spectrum cysteine-reactive compound, iodoacetamide. Our results thus indicate that combination of APR-246 with immunomodulatory agents may elicit effective antitumor immune response irrespective of the tumor's p53 mutation status.

Circulating Tumor DNA from Ascites as an alternative to tumor sampling for genomic profiling in ovarian cancer patients.

Genomic testing is crucial for the management of ovarian cancer. DNA from biopsies at diagnostic laparoscopies or interval debulking surgery after neoadjuvant chemotherapy, has a high failure rate. At relapse, biopsies may not be feasible. The aim of our study was to evaluate the feasibility and usefulness of measuring genomic instability score (GIS) on cell-free DNA (cfDNA) from ascites.Patients enrolled in a prospective study (NCT03010124) consented to analysis of biological samples. CfDNA was extracted from 1 to 4 ml of double-centrifuged fresh ascites. Targeted Next-generation sequencing (NGS) including TP53 mutation (TP53m) was performed on cfDNA to confirm the presence of tumor cfDNA. Single Nucleotide Polymorphism Array estimating somatic copy number alterations (SCNA) was performed to calculate GIS for Homologous-Recombination deficiency (HRD).Twenty nine ascites were collected from 20 patients with suspected or confirmed OC. 93% (27/29) samples had detectable cfDNA (median 1120 ng [24-5732]) even when obtained during chemotherapy. A deleterious mutation was identified in 100%, with high allelic frequencies (median 60% [3.3-87%]), confirming that cfDNA was tumoral. SCNA analyses on 17 patients showed 11 high GIS, and 6 low GIS. 4 patients with confirmed BRCA mutation had a high GIS on ascites. When available from the same patient, SCNA profiles on ascites and tumor were superimposable.Ascites is frequent at diagnosis and relapse and yields large amounts of tumoral cfDNA. SCNA analysis on ascitic cfDNA is feasible and can detect the same HRD scar as tumor testing. Ascites could provide an alternative to tumor sampling for HRD and BRCA testing.

Combined Tumor-Based BRCA1/2 and TP53 Mutation Testing in Ovarian Cancer.

Somatic/germline BRCA1/2 mutations (m)/(likely) pathogenic variants (PV) (s/gBRCAm) remain the best predictive biomarker for PARP inhibitor efficacy. As >95% of high-grade serous ovarian cancers (HGSOC) have a somatic TP53m, combined tumor-based BRCA1/2 (tBRCA) and TP53 mutation testing (tBRCA/TP53m) may improve the quality of results in somatic BRCAm identification and interpretation of the 'second hit' event, i.e., loss of heterozygosity (LOH). A total of 237 patients with HGSOC underwent tBRCA/TP53m testing. The ratio of allelic fractions (AFs) for tBRCA/TP53m was calculated to estimate the proportion of cells carrying BRCAm and to infer LOH. Among the 142/237 gBRCA results, 16.2% demonstrated a pathogenic/deleterious variant (DEL) gBRCA1/2m. Among the 195 contributive tumor samples, 43 DEL of tBRCAm (22.1%) were identified (23 gBRCAm and 20 sBRCAm) with LOH identified in 37/41 conclusive samples. The median AF of TP53m was 0.52 (0.01-0.93), confirming huge variability in tumor cellularity. Initially, three samples were considered as wild type with <10% cellularity. However, additional testing detected a very low AF (<0.05) in both BRCA1/2m and TP53m, thus reidentifying them as sBRCA1/2m. Combined tBRCA/TP53m testing is rapid, sensitive, and identifies somatic and germline BRCA1/2m. AF TP53m is essential for interpreting sBRCA1/2m in low-cellularity samples and provides indirect evidence for LOH as the 'second hit' of BRCA1/2-related tumorigenesis.

Clinical Relevance of BRCA1 Promoter Methylation Testing in Patients with Ovarian Cancer.

PURPOSE: Homologous recombination deficiency (HRD) is closely related to PARP inhibitor (PARPi) benefit in ovarian cancer. The capacity of BRCA1 promoter methylation to predict prognosis and HRD status remains unclear. We aimed to correlate BRCA1 promoter methylation levels in patients with high-grade ovarian cancer to HRD status and clinical behavior to assess its clinical relevance. EXPERIMENTAL DESIGN: This is a retrospective monocentric analysis of patients centrally tested for genomic instability score (GIS) by MyChoice CDx (Myriad Genetics). The detection of BRCA1 promoter methylation and quantification of methylation levels were performed by quantitative droplet digital PCR methodology. High BRCA1 methylation was defined as ≥70% and deemed to be associated with homozygous silencing. RESULTS: Of 100 patients, 11% harbored a deleterious BRCA1/2 mutation. GIS was considered positive (score ≥ 42) for 52 patients and negative for 48 patients. Using a 70% cutoff, 19% (15/79) of BRCA wild-type ovarian cancer had high BRCA1 methylation levels. All of the highly methylated tumors were classified as HRD, achieving a positive predictive value of 100%. We detected 14% (11/79) low-methylated tumors (1%-69%), and all of them were also classified as HRD. Mean GIS was 61.5 for BRCAmut, 66.4 for high-BRCAmeth, 58.9 for low-BRCAmeth, and 33.3 for BRCAwt unmethylated (P < 0.001). Low methylation levels detected in samples previously exposed to chemotherapy appeared to be associated with poor outcome post-platinum. CONCLUSIONS: Patients with ovarian cancer with high levels of BRCA1 hypermethylation are very likely to have high GIS and therefore represent good candidates for PARPi treatment. These results may be highly relevant to other tumor types for HRD prediction. See related commentary by Garg and Oza, p. 2957.

Increased p53 expression induced by APR-246 reprograms tumor-associated macrophages to augment immune checkpoint blockade.

In addition to playing a major role in tumor cell biology, p53 generates a microenvironment that promotes antitumor immune surveillance via tumor-associated macrophages. We examined whether increasing p53 signaling in the tumor microenvironment influences antitumor T cell immunity. Our findings indicate that increased p53 signaling induced either pharmacologically with APR-246 (eprenetapopt) or in p53-overexpressing transgenic mice can disinhibit antitumor T cell immunity and augment the efficacy of immune checkpoint blockade. We demonstrated that increased p53 expression in tumor-associated macrophages induces canonical p53-associated functions such as senescence and activation of a p53-dependent senescence-associated secretory phenotype. This was linked with decreased expression of proteins associated with M2 polarization by tumor-associated macrophages. Our preclinical data led to the development of a clinical trial in patients with solid tumors combining APR-246 with pembrolizumab. Biospecimens from select patients participating in this ongoing trial showed that there was a suppression of M2-polarized myeloid cells and increase in T cell proliferation with therapy in those who responded to the therapy. Our findings, based on both genetic and a small molecule-based pharmacological approach, suggest that increasing p53 expression in tumor-associated macrophages reprograms the tumor microenvironment to augment the response to immune checkpoint blockade.

Cancer cell-autonomous overactivation of PARP1 compromises immunosurveillance in non-small cell lung cancer.

BACKGROUND: High activity of poly(ADP-ribose) polymerase-1 (PARP1) in non-small cell lung cancer (NSCLC) cells leads to an increase in immunohistochemically detectable PAR, correlating with poor prognosis in patients with NSCLC, as well as reduced tumor infiltration by cytotoxic T lymphocytes (CTLs). Intrigued by this observation, we decided to determine whether PARP1 activity in NSCLC cells may cause an alteration of anticancer immunosurveillance. METHODS: Continuous culture of mouse NSCLC cells in the presence of cisplatin led to the generation of cisplatin-resistant PARhigh clones. As compared with their parental controls, such PARhigh cells formed tumors that were less infiltrated by CTLs when they were injected into immunocompetent mice, suggesting a causative link between high PARP1 activity and compromised immunosurveillance. To confirm this cause-and-effect relationship, we used CRISPR/Cas9 technology to knock out PARP1 in two PARhigh NSCLC mouse cell lines (Lewis lung cancer [LLC] and tissue culture number one [TC1]), showing that the removal of PARP1 indeed restored cisplatin-induced cell death responses. RESULTS: PARP1 knockout (PARP1KO) cells became largely resistant to the PARP inhibitor niraparib, meaning that they exhibited less cell death induction, reduced DNA damage response, attenuated metabolic shifts and no induction of PD-L1 and MHC class-I molecules that may affect their immunogenicity. PARhigh tumors implanted in mice responded to niraparib irrespective of the presence or absence of T lymphocytes, suggesting that cancer cell-autonomous effects of niraparib dominate over its possible immunomodulatory action. While PARhigh NSCLC mouse cell lines proliferated similarly in immunocompetent and T cell-deficient mice, PARP1KO cells were strongly affected by the presence of T cells. PARP1KO LLC tumors grew more quickly in immunodeficient than in immunocompetent mice, and PARP1KO TC1 cells could only form tumors in T cell-deficient mice, not in immunocompetent controls. Importantly, as compared with PARhigh controls, the PARP1KO LLC tumors exhibited signs of T cell activation in the immune infiltrate such as higher inducible costimulator (ICOS) expression and lower PD-1 expression on CTLs. CONCLUSIONS: These results prove at the genetic level that PARP1 activity within malignant cells modulates the tumor microenvironment.

Targeting genome integrity dysfunctions impedes metastatic potency in non-small cell lung cancer circulating tumor cell-derived explants.

DNA damage and genomic instability contribute to non-small cell lung cancer (NSCLC) etiology and progression. However, their therapeutic exploitation is disappointing. CTC-derived explants (CDX) offer systems for mechanistic investigation of CTC metastatic potency and may provide rationale for biology-driven therapeutics. Four CDX models and 3 CDX-derived cell lines were established from NSCLC CTCs and recapitulated patient tumor histology and response to platinum-based chemotherapy. CDX (GR-CDXL1, GR-CDXL2, GR-CDXL3, GR-CDXL4) demonstrated considerable mutational landscape similarity with patient tumor biopsy and/or single CTCs. Truncal alterations in key DNA damage response (DDR) and genome integrity-related genes were prevalent across models and assessed as therapeutic targets in vitro, in ovo, and in vivo. GR-CDXL1 presented homologous recombination deficiency linked to biallelic BRCA2 mutation and FANCA deletion, unrepaired DNA lesions after mitosis, and olaparib sensitivity, despite resistance to chemotherapy. SLFN11 overexpression in GR-CDXL4 led to olaparib sensitivity and was in coherence with neuroendocrine marker expression in patient tumor biopsy, suggesting a predictive value of SLFN11 in NSCLC histological transformation into small cell lung cancer (SCLC). Centrosome clustering promoted targetable chromosomal instability in GR-CDXL3 cells. These CDX unravel DDR and genome integrity-related defects as a central mechanism underpinning metastatic potency of CTCs and provide rationale for their therapeutic targeting in metastatic NSCLC.

Evaluating immune response in vitro in a relevant microenvironment: a high-throughput microfluidic model for clinical screening.

Aim: Functional screening of new pharmaceutical compounds requires clinically relevant models to monitor essential cellular and immune responses during cancer progression, with or without treatment. Beyond survival, the emergence of resistant tumor cell clones should also be considered, including specific properties related to plasticity, such as invasiveness, stemness, escape from programmed cell death, and immune response. Numerous pathways are involved in these processes. Defining the relevant ones in the context of a specific tumor type will be key to designing an appropriate combination of inhibitors. However, the diversity and potential redundancy of these pathways remain a challenge for therapy. Methods: A new microfluidic device developed by Okomera was dedicated to the screening of drug treatment for breast cancer. This microchip includes 150 droplet-trapping microwells, offering multi-chip settings and multiple treatment choices. Results: After validating the system with established cell lines and a panel of drugs used clinically at Gustave Roussy, preclinical experiments were initiated including patient-derived xenograft (PDX) and primary tumor cells-derived tumoroids with the collaboration of Gustave Roussy clinicians. Tumor-isolated lymphocytes were also added to the tumoroids, using secondary droplets in proof-of-concept experiments. Conclusions: These results show the relevance of the methodology for screening large numbers of drugs, a wide range of doses, and multiple drug combinations. This methodology will be used for two purposes: 1) new drug screening from the compound library, using the high throughput potential of the chip; and 2) pre-clinical assay for a two-weeks response for personalized medicine, allowing evaluation of drug combinations to flag an optimized treatment with potential clinical application.

Pyridoxal kinase and poly(ADP-ribose) affect the immune microenvironment of locally advanced cancers.

Malignant cells adapt to the hostile tumor microenvironment by escaping from, or actively suppressing, anticancer immune responses. In the past, we reported that reduced synthesis of active vitamin B6 (due to downregulation of pyridoxal kinase) or overactivation of poly(ADP-ribose) polymerase confers resistance to chemotherapy with cisplatin. Recently, we found that these prognostically adverse alterations in oncometabolism also correlate with the rarefaction of immune effectors in the tumor bed.

Metabolic features of cancer cells impact immunosurveillance.

BACKGROUND: Tumors rewire their metabolism to achieve robust anabolism and resistance against therapeutic interventions like cisplatin treatment. For example, a prolonged exposure to cisplatin causes downregulation of pyridoxal kinase (PDXK), the enzyme that generates the active vitamin B6, and upregulation of poly ADP-ribose (PAR) polymerase-1 (PARP1) activity that requires a supply of nicotinamide (vitamin B3) adenine dinucleotide. We investigated the impact of the levels of PDXK and PAR on the local immunosurveillance (ie, density of the antigen presenting cells and adaptive immune response by CD8 T lymphocytes) in two different tumor types. METHODS: Tumors from patients with locally advanced cervical carcinoma (LACC) and non-small cell lung cancer (NSCLC) were stained for PAR, PDXK, dendritic cell lysosomal associated membrane glycoprotein (DC-LAMP) and CD8 T cell infiltration. Their correlations and prognostic impact were assessed. Cisplatin-resistant NSCLC cell clones isolated from Lewis-lung cancer (LLC) cells were evaluated for PAR levels by immunoblot. Parental (PARlow) and cisplatin-resistant (PARhigh) clones were subcutaneously injected into the flank of C57BL/6 mice. Tumors were harvested to evaluate their immune infiltration by flow cytometry. RESULTS: The infiltration of tumors by CD8 T and DC-LAMP+ cells was associated with a favorable overall survival in patients with LACC (p=0.006 and p=0.008, respectively) and NSCLC (p<0.001 for both CD8 T and DC-LAMP cells). We observed a positive correlation between PDXK expression and the infiltration by DC-LAMP (R=0.44, p=0.02 in LACC, R=0.14, p=0.057 in NSCLC), and a negative correlation between PAR levels and CD8 T lymphocytes (R=-0.39, p=0.034 in LACC, R=-0.18, p=0.017 in NSCLC). PARP1 is constitutively hyperactivated in cisplatin-resistant LLC cells manifesting elevated intracellular levels of poly(ADP-ribosyl)ated proteins (PARhigh). Tumors formed by such cancer cells injected into immunocompetent mice were scarcely infiltrated by CD8 T (p=0.028) and antigen presenting cells (p=0.086). CONCLUSIONS: Oncometabolic features can impact local immunosurveillance, providing new functional links between cisplatin resistance and therapeutic failure.

Neoadjuvant chemotherapy alters the balance of effector to suppressor immune cells in advanced ovarian cancer.

BACKGROUND: At diagnosis, tumor-infiltrating lymphocytes (TILs) are prognostic in epithelial ovarian cancer (EOC). We recently demonstrated that neoadjuvant chemotherapy (NACT) significantly increased stromal TILs. Here, we investigated the impact of NACT on immune subpopulations with a particular focus on the balance of immune-reactive to tolerant subpopulations. MATERIALS AND METHODS: Tissue microarrays of EOC (145 pre-NACT, 139 post-NACT) were analyzed for CD3+, CD8+, FOXP3+, CD68+, and CD163+ by immunohistochemistry and CD4+ cells from deduction. Stromal TILs scored as percentage of stromal area, while intra-epithelial TILs scored as number of TILs in contact with tumor cells/HPF. Differences were evaluated by Wilcoxon or Chi square tests, Wilcoxon signed-rank for paired analyses, and cox model for PFS and OS. RESULTS: NACT significantly increased stromal CD3+ (p = 0.003) and CD8+ (p = 0.001) and intra-epithelial CD8+ (p = 0.022) and CD68+ (p = 0.0003) infiltration in unmatched samples and among paired samples for stromal CD3+ and CD8+. Neither CD3+, CD8+, CD4+, and CD68+ nor CD163+ expression correlated with outcome at diagnosis or post NACT. Using median value as a cut-off, high stromal CD8+/FOXP3+ ratio (HR = 0.59; p = 0.017) and high stromal CD3+/FOXP3+ ratio post NACT were associated with prolonged PFS (p = 0.0226). The more the balance shifted in favor of effector versus regulatory TILs, the better the survival. Similarly, high CD68+/CD163+ ratio post NACT improved PFS (p = 0.0445). CONCLUSION: NACT has a significant impact on the balance of immune-reactive to immune-tolerant subpopulations and a high ratio of CD8+/FOXP3+, CD3+/FOXP3+, and CD68+/CD163+ post NACT was significantly associated with improved outcomes. Whether this could select patients for immunotherapy in the post-operative setting should be investigated.

Impact of young age on platinum response in women with epithelial ovarian cancer: Results of a large single-institution registry.

OBJECTIVE: In young women, EOC is a rare disease with an uncertain genetic and biological substrate. METHODS: We report a long follow-up of EOC patients treated at Gustave Roussy between 1990 and 2009. We matched young patients aged ≤30 years to randomly selected older patients aged ≥40 years according to known prognostic factors (i.e. FIGO stage, histology and surgical residual disease) and the date of diagnosis with a threshold at the year 2000 to balance the treatment procedures. RESULTS: EOC was diagnosed in 68 patients aged ≤30 years matched with 111 patients aged ≥40 years. Low-grade (LG) (i.e. serous and endometrioid) (52%, n = 35) and mucinous (i.e. 23%, n = 16 infiltrative and 12% n = 8 expansile) tumors are prevalent. High-grade (HG) tumors are rare (7%, n = 5). Early stage diseases (53%, n = 36 FIGO I/II) are predominant. Response to platinum based chemotherapy is observed to be inferior in young patients as compared to matched older patients (ORR, 29 vs 84% p = 0.0002). For HG tumors the PFS is of 0% at 5 and 10 years in younger as compared to 30% in older patients. No difference in PFS (median 4.9 vs 9.8 ms, p = 0.58) and OS (not reached vs 15.3 ms, p = 0.47) is found overall among younger and older patients respectively. The median follow-up was 72 months (range, 11-288 months). No genetic abnormalities were found. CONCLUSIONS: Young EOC patients are most often diagnosed at an early FIGO stage with LG serous or mucinous histology. Tumors are significantly more resistant to platinum-based chemotherapy in younger patients.

Metabolic enzymes expressed by cancer cells impact the immune infiltrate.

The expression of two metabolic enzymes, i.e., aldehyde dehydrogenase 7 family, member A1 (ALDH7A1) and lipase C, hepatic type (LIPC) by malignant cells, has been measured by immunohistochemical methods in non-small cell lung carcinoma (NSCLC) biopsies, and has been attributed negative and positive prognostic value, respectively. Here, we demonstrate that the protein levels of ALDH7A1 and LIPC correlate with the levels of the corresponding mRNAs. Bioinformatic analyses of gene expression data from 4921 cancer patients revealed that the expression of LIPC positively correlates with abundant tumor infiltration by myeloid and lymphoid cells in NSCLC, breast carcinoma, colorectal cancer and melanoma samples. In contrast, high levels of ALDH7A1 were associated with a paucity of immune effectors within the tumor bed. These data reinforce the notion that the metabolism of cancer cells has a major impact on immune and inflammatory processes in the tumor microenvironment, pointing to hitherto unsuspected intersections between oncometabolism and immunometabolism.

Renal toxicities associated with pembrolizumab.

OBJECTIVE: Expanded clinical experience with patients treated by pembrolizumab has accumulated. However, renal toxicities associated with this anti-programmed cell death 1 agent are poorly described because kidney histology is rarely sought. As a nephrology referral centre, we aimed to describe the clinic-biological and histopathological characteristics of pembrolizumab-related nephropathy and its response to treatment. METHODS: We conducted a monocentric large case series study, including all pembrolizumab-treated cancer patients presenting a renal toxicity addressed to our centre from 2015 to 2017. RESULTS: A total of 12 patients (7 men) out of 676 pembrolizumab-treated patients (incidence 1.77%) were included (median age 69.75 years). Patients were referred for acute kidney injury (n = 10) and/or proteinuria (n = 2). A kidney biopsy was performed in all patients, with a median duration of use of 9 months (range 1-24 months) after the beginning of treatment. Biopsy showed that four patients had acute interstitial nephritis (AIN), whereas five had acute tubular injury (ATI) alone, one had minimal change disease (MCD) and ATI, and one had MCD alone. Pembrolizumab withdrawal coupled with corticosteroid therapy was the most effective treatment for kidney function recovery. Drug reintroduction resulted in a more severe recurrence of AIN in one patient who required maintenance of pembrolizumab. Two patients died of cancer progression with one of them developing severe renal failure requiring dialysis. CONCLUSION: In our series, ATI, AIN and MCD are the most frequent forms of kidney involvement under pembrolizumab therapy. Kidney dysfunction is usually isolated but can be severe. Use of corticosteroids in case of AIN improves the glomerular filtration rate.

Metabolic vulnerability of cisplatin-resistant cancers.

Cisplatin is the most widely used chemotherapeutic agent, and resistance of neoplastic cells against this cytoxicant poses a major problem in clinical oncology. Here, we explored potential metabolic vulnerabilities of cisplatin-resistant non-small human cell lung cancer and ovarian cancer cell lines. Cisplatin-resistant clones were more sensitive to killing by nutrient deprivation in vitro and in vivo than their parental cisplatin-sensitive controls. The susceptibility of cisplatin-resistant cells to starvation could be explained by a particularly strong dependence on glutamine. Glutamine depletion was sufficient to restore cisplatin responses of initially cisplatin-resistant clones, and glutamine supplementation rescued cisplatin-resistant clones from starvation-induced death. Mass spectrometric metabolomics and specific interventions on glutamine metabolism revealed that, in cisplatin-resistant cells, glutamine is mostly required for nucleotide biosynthesis rather than for anaplerotic, bioenergetic or redox reactions. As a result, cisplatin-resistant cancers became exquisitely sensitive to treatment with antimetabolites that target nucleoside metabolism.

Multiplex bead-based measurement of humoral immune responses against tumor-associated antigens in stage II melanoma patients of the EORTC18961 trial.

Purpose: Determine the prognostic and predictive significance of tumor associated antigen (TAA)-specific serum antibodies in melanoma patients of a large adjuvant vaccination phase III trial. Patients and methods: Serum IgG antibodies were measured against a panel of 43 antigens by a bead-based multiplex assay in 970 stage II melanoma patients of the EORTC18961 trial, evaluating adjuvant ganglioside GM2-KLH/QS-21 vaccination versus observation. Primary end point was relapse-free survival (RFS). Patients' sera at baseline, after 12 and 48 weeks of study treatment and at the last available time point (at recurrence/remission) were evaluated. Results: Prognostic clinical variables are gender, surgical confirmation of lymph node-negative status, Breslow thickness and ulceration of the primary. Prognostic spontaneous antibody responses were associated with a significant dismal (GM2, Rhod_E2, SSX2) or good prognosis (CyclinB1, SCYE1v1) for RFS, distant metastasis-free (DMFS) or overall survival (OS). Predictive spontaneous antibody responses based on significant interaction with treatment were RhodN p = 0.02, Rab38 p = 0.04 for RFS, RhodE2 p = 0.006, Recoverin p = 0.04 for DMFS and RhodE2 p = 0.003; Recoverin p = 0.04, NA17.A p = 0.04, for OS respectively. The subgroups of patients according to antibody responses for RFS were determined for RhodN sero-negative (n = 849, HR = 1.07, p = 0.6); RhodN sero-positive (n = 121,HR = 0.42, p = 0.01) and Rab38 sero-negative (n = 682, HR = 1.12, p = 0.42), Rab38 sero-positive (n = 288, HR = 0.65, p = 0.04) patients respectively. Conclusion: We identified prognostic serum antibody responses against TAA in stage II melanoma patients. A set of antibody responses correlated with a beneficial outcome for GM2 vaccination.

Tumours with class 3 BRAF mutants are sensitive to the inhibition of activated RAS.

Approximately 200 BRAF mutant alleles have been identified in human tumours. Activating BRAF mutants cause feedback inhibition of GTP-bound RAS, are RAS-independent and signal either as active monomers (class 1) or constitutively active dimers (class 2). Here we characterize a third class of BRAF mutants-those that have impaired kinase activity or are kinase-dead. These mutants are sensitive to ERK-mediated feedback and their activation of signalling is RAS-dependent. The mutants bind more tightly than wild-type BRAF to RAS-GTP, and their binding to and activation of wild-type CRAF is enhanced, leading to increased ERK signalling. The model suggests that dysregulation of signalling by these mutants in tumours requires coexistent mechanisms for maintaining RAS activation despite ERK-dependent feedback. Consistent with this hypothesis, melanomas with these class 3 BRAF mutations also harbour RAS mutations or NF1 deletions. By contrast, in lung and colorectal cancers with class 3 BRAF mutants, RAS is typically activated by receptor tyrosine kinase signalling. These tumours are sensitive to the inhibition of RAS activation by inhibitors of receptor tyrosine kinases. We have thus defined three distinct functional classes of BRAF mutants in human tumours. The mutants activate ERK signalling by different mechanisms that dictate their sensitivity to therapeutic inhibitors of the pathway.