Overexpression of WT1 in all molecular subtypes of breast cancer and its impact on survival: exploring oncogenic and tumor suppressor roles of distinct WT1 isoforms.

BACKGROUND: Breast cancer is a highly heterogeneous solid tumor, posing challenges in developing targeted therapies effective for all mammary carcinoma subtypes. WT1 emerges as a promising target for breast cancer therapy due to its potential oncogenic role in various cancer types. Previous works have yielded inconsistent results. Therefore, further studies are needed to clarify the behavior of this complex gene in breast cancer. METHODS AND RESULTS: In this study, we examined WT1 expression in both Formalin Fixed Paraffin Embedded breast tumors (n = 41) and healthy adjacent tissues (n = 41) samples from newly diagnosed cases of ductal invasive breast cancer. The fold change in gene expression between the tumor and healthy tissue was determined by calculating 2-∆∆Ct. Disease-free survival analysis was computed using the Kaplan-Meier method. To identify the expression levels of different WT1 isoforms, we explored the ISOexpresso database. Relative quantification of the WT1 gene revealed an overexpression of WT1 in most cases. The percentage of patients surviving free of disease at 8 years of follow-up was lower in the group overexpressing WT1 compared to the group with down-regulated WT1. CONCLUSIONS: Interestingly, this overexpression was observed in all molecular subtypes of invasive breast cancer, underscoring the significance of WT1 as a potential target in all these subtypes. The observed WT1 down-expression in a few cases of invasive breast cancer, associated with better survival outcomes, may correspond to the down-regulation of a particular WT1-KTS (-) isoform: the WT1 A isoform (EX5-/KTS-). The co-expression of this WT1 oncogenic isoform with a regulated WT1- tumor suppressor isoform, such as the major WT1 F isoform (EX5-/KTS +), could also explain such survival outcomes. Due to its capacity to adopt dual roles, it becomes imperative to conduct individual molecular expression profiling of the WT1 gene. Such an approach holds great promise in the development of personalized treatment strategies for breast cancer.

[Gene Profile and Clinical Significance of Concomitant Mutations in CN-AML Patients with CEBPA Mutation].

OBJECTIVE: To analyze the occurrence of concomitant gene mutations in cytogenetically normal acute myeloid leukemia (CN-AML) patients with CEBPA mutation and its impact on the clinical characteristics and prognosis of the patients. METHODS: 151 newly diagnosed patients with CN-AML in the Second Hospital of Shanxi Medical University from June 2013 to June 2020 were analyzed retrospectively. 34 common genetic mutations associated with hematologic malignancies were detected by next-generation sequencing technology. The occurrence of concomitant gene mutations in patients with CEBPA positive and negative groups was compared, and the correlation between concomitant mutations in different functional groups and the clinical characteristics and prognosis of CN-AML patients with CEBPA mutation was analyzed. RESULTS: In 151 patients with CN-AML, 55 (36.42%) were positive for CEBPA mutation (including 36 cases of CEBPAdm and 19 cases of CEBPAsm), of which 41 (74.55%) had co-mutations with other genes. The main mutated genes were GATA2 (25.45%, 14/55), TET2 (21.82%, 12/55), FLT3 (20.00%, 11/55), NRAS (12.73%, 7/55) and WT1 (9.09%, 9/55), etc. Some cases had two or more concomitant gene mutations. Grouping the mutant genes according to their functions showed that CEBPA+ group had lower mutation rates of histone methylation (P =0.002) and chromatin modification genes (P =0.002, P =0.033), and higher mutation rates of transcription factors (P =0.037) than CEBPA- group. In 55 patients with CEBPA+ CN-AML, the platelet count at diagnosis in signaling pathway gene mutation-positive group was lower than that in the mutation-negative group (P =0.005), the proportion of bone marrow blasts in transcription factor mutation-positive group was higher than that in the mutation-negative group (P =0.003), and the onset age in DNA methylation gene mutation-positive group and chromatin modifier mutation-positive group was older than that in the mutation-negative group, respectively (P =0.002, P =0.008). DFS of CEBPA+ CN-AML patients in signaling pathway gene mutation group was shorter than that in signaling pathway gene mutation-negative group (median DFS: 12 months vs not reached) (P =0.034). Compared with DNA methylation gene mutation-negative group, CEBPA+ CN-AML patients with DNA methylation gene mutation had lower CR rate (P =0.025) significantly shorter OS and DFS (median OS: 20 months vs not reached, P =0.006; median DFS: 15 months vs not reached, P =0.049). OS in patients with histone methylation gene mutation was significantly shorter than that in the histone methylation gene mutation-negative group (median OS: 12 months vs 40 months) (P =0.008). Multivariate analysis of prognostic factors showed that the proportion of bone marrow blasts (P =0.046), concomitant DNA methylation gene mutation (P =0.006) and histone methylation gene mutation (P =0.036) were independent risk factors affecting the prognosis. CONCLUSION: CN-AML patients with CEBPA mutation have specific concomitant gene profile, and the concomitant mutations of different functional genes have a certain impact on the clinical characteristics and prognosis of the patients.

Prognostic impact of peripheral blood WT1 mRNA dynamics in patients with acute myeloid leukemia treated with venetoclax combination therapy.

BACKGROUND: Wilms' tumor gene 1 (WT1) mRNA quantification is a useful marker of measurable residual disease in acute myeloid leukemia (AML). However, whether monitoring the WT1 mRNA levels may predict the outcome of venetoclax (VEN) combination therapy in AML is not reported. This study aims to elucidate whether WT1 mRNA dynamics could predict long-term prognosis. METHODS: 33 patients with untreated or relapsed/refractory AML evaluated for peripheral blood WT1 dynamics in VEN combination therapy were analyzed. RESULTS: The median age was 73 years (range 39-87). Azacitidine was combined with VEN in 91% of patients. Overall, the median overall survival (OS) was 334 days (95% CI 210-482), and the complete remission (CR) plus CR with incomplete hematologic recovery rate was 59%. A 1-log reduction of WT1 mRNA values by the end of cycle 2 of treatment was associated with significantly better OS and event-free survival (EFS) (median OS 482 days vs. 237 days, p = 0.049; median EFS 270 days vs. 125 days, p = 0.02). The negativity of post-treatment WT1 mRNA value during the treatment was associated with significantly better OS and EFS (median OS 482 days vs. 256 days, p = 0.02; median EFS not reached vs. 150 days, p = 0.005). Multivariate analysis confirmed the significance of these two parameters as strong EFS predictors (HR 0.26, p = 0.024 and HR 0.15, p = 0.013, respectively). The increase in WT1 mRNA values was correlated with relapse. CONCLUSION: This study demonstrates that WT1 mRNA dynamics can be a useful marker for assessing long-term prognosis of VEN combination therapy for AML.

Dendritic cell vaccination in combination with erlotinib in a patient with inoperable lung adenocarcinoma: a case report.

BACKGROUND: Satisfactory treatment for patients with unresectable advanced lung cancer has not yet been established. We report a case of unresectable advanced lung cancer (stage IIIb: T2aN3M0) treated with a total of 15 doses of dendritic cells pulsed with a Wilms' tumor 1 and mucin 1 vaccine in combination with erlotinib, a small molecule epidermal growth factor receptor tyrosine kinase inhibitor, for more than 699 days without recurrence or metastasis. CASE PRESENTATION: A 63-year-old Korean woman was diagnosed with lung adenocarcinoma by pathology and computed tomography. The adenocarcinoma showed an epidermal growth factor receptor (EGFR) mutation, no anaplastic lymphoma kinase expression, and less than 1% expression of programmed death ligand 1. She received erlotinib alone for approximately 1 month. She then received erlotinib and the dendritic cells pulsed with Wilms' tumor 1 and mucin 1 vaccine. The diameter of the erythema at the vaccinated sites was 30 mm at 48 hours after the first vaccination. Moreover, it was maintained at more than 20 mm during the periods of vaccination. These results suggested the induction of antitumor immunity by the vaccine. Remarkably, the tumor size decreased significantly to 12 mm, a 65.7% reduction, after combined therapy with eight doses of the dendritic cells pulsed with Wilms' tumor 1 and mucin 1 vaccine and erlotinib for 237 days based on fluorodeoxyglucose uptake by positron emission tomography/computed tomography and computed tomography. Interestingly, after 321 days of combination therapy, the clinical findings improved, and no tumor was detected based on computed tomography. Validation of the tumor's disappearance persisted for at least 587 days after treatment initiation, without any indication of recurrence or metastasis. CONCLUSION: Standard anticancer therapy combined with the dendritic cells pulsed with Wilms' tumor 1 and mucin 1 vaccine may have therapeutic effects for such patients with unresectable lung adenocarcinoma.

WT1 and TP53 as valuable diagnostic biomarkers for relapse after hematopoietic stem cell transplantation in acute myeloid leukemia.

BACKGROUND: Relapse following hematopoietic stem cell transplantation (HSCT) occurs relatively frequently and is a significant risk factor for mortality in patients with acute myeloid leukemia (AML). Early diagnosis is, therefore, of utmost importance and can provide valuable guidance for appropriate and timely intervention. Here, the diagnostic value of two molecular markers, Wilms tumor 1 (WT1) and tumor suppressor protein p53 (TP53), were studied. METHODS AND RESULTS: Twenty AML patients undergoing HSCT participated in this investigation. Some had relapsed following HSCT, while others were in remission. Peripheral blood (PB) and bone marrow (BM) samples were collected following relapse and remission. WT1 and TP53 messenger RNA (mRNA) expression was evaluated using reverse transcription-quantitative polymerase chain reaction (RT‒qPCR). The diagnostic value of genes was evaluated by utilizing receiver-operating characteristic (ROC) curve analysis. ROC analysis showed WT1 and TP53 as diagnostic markers for relapse after HSCT in AML patients. The mRNA expression level of WT1 was elevated in individuals who experienced relapse compared to those in a state of remission (p value < 0.01). Conversely, the expression level of TP53 mRNA was lower in individuals who had relapsed compared to those in remission (p value < 0.01). CONCLUSIONS: WT1 and TP53 possess the potential to serve as invaluable biomarkers in the identification of molecular relapse after HSCT in patients with AML. Further studies for a definitive conclusion are recommended.

Wilms' tumor 1 (WT1) antigen is overexpressed in Kaposi Sarcoma and is regulated by KSHV vFLIP.

In people living with HIV, Kaposi Sarcoma (KS), a vascular neoplasm caused by KS herpesvirus (KSHV/HHV-8), remains one of the most common malignancies worldwide. Individuals living with HIV, receiving otherwise effective antiretroviral therapy, may present with extensive disease requiring chemotherapy. Hence, new therapeutic approaches are needed. The Wilms' tumor 1 (WT1) protein is overexpressed and associated with poor prognosis in several hematologic and solid malignancies and has shown promise as an immunotherapeutic target. We found that WT1 was overexpressed in >90% of a total 333 KS biopsies, as determined by immunohistochemistry and image analysis. Our largest cohort from ACTG, consisting of 294 cases was further analyzed demonstrating higher WT1 expression was associated with more advanced histopathologic subtypes. There was a positive correlation between the proportion of infected cells within KS tissues, assessed by expression of the KSHV-encoded latency-associated nuclear antigen (LANA), and WT1 positivity. Areas with high WT1 expression showed sparse T-cell infiltrates, consistent with an immune evasive tumor microenvironment. We show that major oncogenic isoforms of WT1 are overexpressed in primary KS tissue and observed WT1 upregulation upon de novo infection of endothelial cells with KSHV. KSHV latent viral FLICE-inhibitory protein (vFLIP) upregulated total and major isoforms of WT1, but upregulation was not seen after expression of mutant vFLIP that is unable to bind IKKÆ´ and induce NFκB. siRNA targeting of WT1 in latent KSHV infection resulted in decreased total cell number and pAKT, BCL2 and LANA protein expression. Finally, we show that ESK-1, a T cell receptor-like monoclonal antibody that recognizes WT1 peptides presented on MHC HLA-A0201, demonstrates increased binding to endothelial cells after KSHV infection or induction of vFLIP expression. We propose that oncogenic isoforms of WT1 are upregulated by KSHV to promote tumorigenesis and immunotherapy directed against WT1 may be an approach for KS treatment.

Familial focal segmental glomerulosclerosis associated with a WT1 gene missense mutation: A case report.

Focal s egmental glomerulosclerosis (F SGS) can cause protei nuria and loss o f k idney fun ction, leading to e ndstage renal di s ease (ESRD). Podocyte injury is the ce ntral pathophysiologi cal mechanis m of hereditary FSGS. Numerous mutations in genes e ncoding or affe cting the transcriptional regulation of podocyte cell compar tments have been detected in patients with genetic FSGS. Herein, we report a rare case of familial FSGS with an autosomal dominant WT1 mutation. A 63-year- old man developed pro teinuri a; his reading showed over 1g prote in/day. A pa thological diagn osis of FSG S was made after rena l biops y. H is elder brother an d a 36-year- old son also had ESRD. Heterozygous variant of WT1 (NM_024426.4) c.1373G>A (p.Arg458Gln ) mi s sense was dete cted in the patient a nd his son , by whole-exome sequen cing. Although genetic screening is not a par t of routine practice, it s hould be per for med in such cases to a id a ppropriate tre atment options sel ecting, revealing extra ren al symptoms, and family planning.

Wilms' tumor gene 1: lessons from the interface between kidney development and cancer.

In 1990, mutations of the Wilms' tumor-1 gene (WT1), encoding a transcription factor in the embryonic kidney, were found in 10-15% of Wilms' tumors; germline WT1 mutations were associated with hereditary syndromes involving glomerular and reproductive tract dysplasia. For more than three decades, these discoveries prompted investigators to explore the embryonic role of WT1 and the mechanisms by which loss of WT1 leads to malignant transformation. Here, we discuss how alternative splicing of WT1 generates isoforms that act in a context-specific manner to activate or repress target gene transcription. WT1 also regulates posttranscriptional regulation, alters the epigenetic landscape, and activates miRNA expression. WT1 functions at multiple stages of kidney development, including the transition from resting stem cells to committed nephron progenitor, which it primes to respond to WNT9b signals from the ureteric bud. WT1 then drives nephrogenesis by activating WNT4 expression and directing the development of glomerular podocytes. We review the WT1 mutations that account for Denys-Drash syndrome, Frasier syndrome, and WAGR syndrome. Although the WT1 story began with Wilms' tumors, an understanding of the pathways that link aberrant kidney development to malignant transformation still has some important gaps. Loss of WT1 in nephrogenic rests may leave these premalignant clones with inadequate DNA repair enzymes and may disturb the epigenetic landscape. Yet none of these observations provide a complete picture of Wilms' tumor pathogenesis. It appears that the WT1 odyssey is unfinished and still holds a great deal of untilled ground to be explored.

Prophylactic bilateral nephrectomy and preemptive kidney transplantation for Denys-Drash syndrome prior to development of kidney failure.

BACKGROUND  : Nephropathy in Denys-Drash syndrome (DDS) develops within a few months of birth, often progressing to kidney failure. Wilms tumors also develop at an early age with a high rate of incidence. When a patient does not have Wilms tumor but develops kidney failure, prophylactic bilateral nephrectomy, and kidney transplantation (KTX) is an optimal approach owing to the high risk of Wilms tumor development. In the case presented here, prophylactic bilateral nephrectomy and KTX were performed in a patient who had not developed Wilms tumor or kidney failure. However, the treatment option is controversial as it involves the removal of a tumor-free kidney and performing KTX in the absence of kidney failure. CASE DIAGNOSIS/TREATMENT: We present the case of a 7-year-old boy, born at 38 weeks gestation. Examinations at the age of 1 year revealed severe proteinuria and abnormal internal and external genitalia. Genetic testing identified a missense mutation in exon 9 of the WT1 gene, leading to the diagnosis of DDS. At the age of 6 years, he had not yet developed Wilms tumor and had grown to a size that allowed him to safely undergo a KTX. His kidney function was slowly deteriorating (chronic kidney disease (CKD) stage 3), but he had not yet developed kidney failure. Two treatment options were considered for this patient: observation until the development of kidney failure or prophylactic bilateral nephrectomy with KTX to avoid Wilms tumor development. After a detailed explanation of options to the patient and family, they decided to proceed with prophylactic bilateral nephrectomy and KTX. At the latest follow-up 4 months after KTX, the patient's kidney functioned well without proteinuria. CONCLUSION: We performed prophylactic bilateral nephrectomy with KTX on a DDS patient who had not developed kidney failure or Wilms tumor by the age of 7 years. Although the risk of development of Wilms tumor in such a patient is unclear, this treatment may be an optimal approach for patients who are physically able to undergo KTX, considering the potentially lethal nature of Wilms tumor in CKD patients.

EWSR1::WT1 Fusions in Neoplasms Other Than Conventional Desmoplastic Small Round Cell Tumor: Three Tumors Occurring Outside the Female Genital Tract.

Desmoplastic small round cell tumor (DSRCT) is a high-grade, primitive round cell sarcoma classically associated with prominent desmoplastic stroma, coexpression of keratin and desmin, and a characteristic EWSR1::WT1 gene fusion. DSRCT typically arises in the abdominopelvic cavity of young males with diffuse peritoneal spread and poor overall survival. Although originally considered to be pathognomonic for DSRCT, EWSR1::WT1 gene fusions have recently been detected in rare tumors lacking the characteristic morphologic and immunohistochemical features of DSRCT. Here, we report 3 additional cases of neoplasms other than conventional DSCRCT with EWSR1::WT1 gene fusions that occurred outside the female genital tract. Two occurred in the abdominopelvic cavities of a 27-year-old man and a 12-year-old girl, whereas the third arose in the axillary soft tissue of an 85-year-old man. All cases lacked prominent desmoplastic stroma and were instead solid and cystic with peripheral fibrous pseudocapsules and occasional intervening fibrous septa. Necrosis was either absent (1/3) or rare (2/3), and mitotic activity was low (<1 to 3 per 10 hpf). In immunohistochemical studies, there was expression of smooth muscle actin (3/3) and desmin (3/3), rare to focal reactivity for EMA (2/3), and variable expression of CK AE1/AE3 (1/3). Myogenin and MyoD1 were negative, and C-terminus-specific WT1 was positive in both cases tested (2/2). All 3 tumors followed a more indolent clinical course with 2 cases demonstrating no evidence of disease at 20 and 44 months after resection. The patient from case 3 died of other causes at 14 months with no evidence of recurrence. DNA methylation profiling showed that the 3 cases clustered with DSRCT; however, they demonstrated fewer copy number variations with 2 cases having a flat profile (0% copy number variation). Differential methylation analysis with hierarchical clustering further showed variation between the 3 cases and conventional DSRCT. Although further study is needed, our results, in addition to previous reports, suggest that EWSR1::WT1 gene fusions occur in rare and seemingly distinctive tumors other than conventional DSRCT with indolent behavior. Proper classification of these unusual soft tissue tumors with EWSR1::WT1 gene fusions requires direct correlation with tumor morphology and clinical behavior, which is essential to avoid overtreatment with aggressive chemotherapy.

Clinical significance of WT1 in the evaluation of therapeutic effect and prognosis of non-M3 acute myeloid leukemia.

To explore the clinical significance and prognosis of acute myeloid leukemia (AML) patients with WT1 mutations.In total, the clinical data of 269 adult patients with non-M3 AML were considered retrospectively. From these patients, 153 carried WT1 mutation whereas 116 were negative. WT1 mutation positive patients were further divided into WT1 low expression and high expression groups base on the expression level of WT1 by qPCR at diagnosis (cut off: 170500). Survival and therapeutic effect analysis were performed for the above patients with different interfering factors such as co-mutations, the extent of WT1 log reduction and the chemotherapy regimens. Patients with high WT1 expression have higher rate of relapse. We can accurately identify patients with inferior outcomes when we take the following factors into consideration: the WT1 expression level at diagnosis; different prognostic factors including co-mutations (especially NPM1 and FLT3-ITD); the log reduction of WT1 after induction therapy and the risk of stratification. Idarubicin + Cytarabine (IA) regimen could reduce the expression level of WT1 after treatment, and Allo-HSCT played an important role in improving the prognosis of patients with WT1 high expression and patients with WT1 negativity. Among the relapsed patients, there existed a rising trend of WT1-MRD in advance than MFC-MRD and that of patients with continuous complete remission (CR). Different clinical background should be taken into consideration when we judge the prognosis and therapeutic effect of patients with WT1 mutations. In addition, WT1 may be an optional MRD marker, which needs regular monitoring.

[Expression level of Wilms' tumor 1 gene and its correlation with clinical features in patients with myeloproliferative neoplasms].

Objective: To investigate the expression level of WT1 gene in patients with classical Philadelphia chromosome (Ph)-negative myeloproliferative neoplasms (MPN) and its correlation with clinical features. Methods: A retrospective study included 252 patients with newly diagnosed MPN in Zhongnan Hospital of Wuhan University from January 2015 to March 2023, including 128 males and 124 females, aged［M（Q1，Q3）］62 (53, 69) years. The WT1-positive group (n=93) and the WT1-negative group (n=159) were split based on the level of WT1 gene expression, and the variations in clinical indicators between the two groups were compared. Its levels of expression in each subtype and its relationships to thrombotic events and clinically significant variables were analyzed. As of March 31, 2023, the follow-up period [M (Q1, Q3)] was 12.0(6.5,21.0)months. The risk factors of thrombosis in MPN patients were analyzed by using the logistic regression analysis. Results: The WT1 gene expression level in the overall bone marrow samples of 252 patients with newly diagnosed MPN was 0.30% (0.10%, 1.10%). The expression level in primary myelofibrosis (PMF) patients was 1.45% (0.41%, 3.24%), which was higher than 0.15% (0.02%, 0.32%), 0.37% (0.16%, 1.09%) in essential thrombocythemia (ET) and polycythemia vera (PV) patients (both P<0.05). Positive correlations were found between WT1 gene expression levels and JAK2V617F gene mutation load, RDW, MPV (r=0.478, 0.346, 0.236, all P<0.01). While negative correlations between WT1 gene expression levels and PLT, LYM, PTTA, LDH were found (r=-0.339, -0.170, -0.206, -0.388, all P<0.01). Patients in the WT1-positive group exhibited a higher percentage of somatic symptoms, splenomegaly, positive JAK2V617F gene mutation, and higher levels of RDW, LDH, NEUT, and MPV compared to the WT1-negative group. In contrast, the proportion of triple-negative (negative for all three hot mutations of JAK2V617F, CALR and MPL) was lower, and the levels of PLT, LYM and PTTA were lower (all P<0.05). The thrombotic event rates of WT1-positive group and WT1-negative group were 32.3% (30/93) and 32.1% (51/159), respectively, and the difference was not statistically significant (P=0.883). Logistic regression analysis showed that male (OR=2.41,95%CI:1.02-5.71,P=0.046) and positive JAK2V617F gene mutation (OR=3.96,95%CI:1.50-10.42,P=0.005) were risk factors for thrombotic events in ET patients. Conclusions: WT1 gene expression is elevated in PMF patients and correlated with indicators of disease progression and transformation in MPN patients. It can be utilized as an auxiliary diagnostic indicator for classical MPN staging but is not correlated with the incidence of thrombotic events. Male and positive JAK2V617F gene mutation are risk factors for thrombotic events in ET patients.

The -KTS splice variant of WT1 is essential for ovarian determination in mice.

Sex determination in mammals depends on the differentiation of the supporting lineage of the gonads into Sertoli or pregranulosa cells that govern testis and ovary development, respectively. Although the Y-linked testis-determining gene Sry has been identified, the ovarian-determining factor remains unknown. In this study, we identified -KTS, a major, alternatively spliced isoform of the Wilms tumor suppressor WT1, as a key determinant of female sex determination. Loss of -KTS variants blocked gonadal differentiation in mice, whereas increased expression, as found in Frasier syndrome, induced precocious differentiation of ovaries independently of their genetic sex. In XY embryos, this antagonized Sry expression, resulting in male-to-female sex reversal. Our results identify -KTS as an ovarian-determining factor and demonstrate that its time of activation is critical in gonadal sex differentiation.

Conformation-selective rather than avidity-based binding to tumor associated antigen derived peptide-MHC enables targeting of WT1-pMHC low expressing cancer cells by anti-WT1-pMHC/CD3 T cell engagers.

T cell engagers, a category of T cell-retargeting immunotherapy, are rapidly transforming clinical cancer care. However, the lack of tumor-specific targets poses a significant roadblock for broad adaptation of this therapeutic modality in many indications, often resulting in systemic on-target off-tumor toxicity. Though various tumor-derived intracellular mutations provide a massive pool of potential tumor-specific antigens, targeting them is extremely challenging, partly due to the low copy number of tumor associated antigen (TAA)-derived pMHC on tumor cell surface. Further, the interplay of binding geometry and format valency in relation to the capacity of a T cell engager to efficiently target low density cell-surface pMHC is not well understood. Using the Wilms' tumor 1 (WT1) oncoprotein as a proof-of-principle TAA, combined with an array of IgG-like T cell engager modalities that differ in their anti-TAA valency and binding geometry, we show that the ability to induce an immunological synapse formation, resulting in potent killing of WT1 positive cancer cell lines is primarily dependent on the distinct geometrical conformations between the Fab arms of anti-WT1-HLA-A*02:01 and anti-CD3. The augmented avidity conferred by the binding of two anti-WT1-HLA-A*02:01 Fab arms has only minimal influence on cell killing potency. These findings demonstrate the need for careful examination of key design parameters for the development of next-generation T cell engagers targeting low density TAA-pMHCs on tumor cells.

Wilms' tumour gene 1 (WT1) enhances non-small cell lung cancer malignancy and is inhibited by microRNA-498-5p.

BACKGROUND: Wilms' tumour gene 1 (WT1) is clearly recognized as a tumour promoter in diversiform of human malignancies. Nevertheless, knowledge of its expression, functions and potential molecular mechanisms in non-small cell lung cancer (NSCLC) remains elusive. METHODS: Differential expression of WT1 mRNA and protein between NSCLC and normal tissues were assessed by analyzing RNA-seq data from Oncomine and protein data from Human Protein Atlas, respectively. Subsequently, prognosis significance and immune cell infiltration were analyzed by Kaplan-Meier plotter and CIBERSORT. 60 pairs of local NSCLC tissues were involved to validate WT1 expression by quantitative PCR (qPCR) and Western blot. Moreover, Cell Counting Kit-8 (CCK-8), colony formation, transwell, dual luciferase reporter assays and in vivo xenograft tumour growth experiments were conducted to explore the function and mechanism of WT1 in NSCLC. RESULTS: Our solid data indicated that WT1 was increased in NSCLC tissues and cell lines in comparison with their matched controls. In particular, its upregulation correlated with worse prognosis and immune infiltration of the patients. Functional assays demonstrated that knockdown of WT1 inhibited NSCLC malignancy, including inhibiting cell proliferation, survival and invasion. Further exploration discovered that microRNA-498-5p (miR-498-5p) was the upstream suppressor of WT1 by directly targeting the 3' untranslated region (UTR) of WT1 mRNA. Moreover, expression of miR-498-5p was notably decreased and inversely correlated with WT1 in NSCLC tissues. Finally, we proved that miR-498-5p was a potent tumour suppressor in NSCLC by suppressing cell proliferation, survival and invasion, while WT1 restoration could in turn disrupt this suppression both in vitro and in vivo. CONCLUSION: The abnormal increase in WT1 contributes to the malignant properties of NSCLC cells, and miR-498-5p is a natural inhibitor of WT1. Our findings might facilitate the development of novel therapeutic strategies against NSCLC in the future.

WT1-mutated acute myeloid leukemia is sensitive to fludarabine-based chemotherapy and conditioning regimens.

We conducted a retrospective analysis of WT1-mutated acute myeloid leukemia (AML) patients who underwent allogeneic stem cell transplant. Thirty-seven patients with WT1-mutated AML were identified. Primary induction failure (40%) and early relapse rate (18%) after idarubicin/cytarabine (7 + 3) chemotherapy were observed. All patients with induction failure subsequently achieved CR with additional chemotherapy. There was no significant difference between outcomes after myeloablative vs. reduced intensity (Fludarabine/Melphalan [Flu/Mel]) conditioning regimens. RFS but not OS was significantly better in patients who received FLAG-IDA prior to transplant and/or a fludarabine-containing conditioning. In an independent ex vivo study, WT1-mutated AML samples exhibited greater sensitivity to fludarabine (p = 0.026) and melphalan (p = 0.0005) than non-WT1-mutated AML samples while there was no difference between sensitivity to cytarabine. Our data favor using a fludarabine-based induction for AML with WT1 mutation instead of 7 + 3. Fludarabine conditioning regimens for alloHCT showed better RFS but not OS.