A glycolytic metabolite bypasses "two-hit" tumor suppression by BRCA2.

Knudson's "two-hit" paradigm posits that carcinogenesis requires inactivation of both copies of an autosomal tumor suppressor gene. Here, we report that the glycolytic metabolite methylglyoxal (MGO) transiently bypasses Knudson's paradigm by inactivating the breast cancer suppressor protein BRCA2 to elicit a cancer-associated, mutational single-base substitution (SBS) signature in nonmalignant mammary cells or patient-derived organoids. Germline monoallelic BRCA2 mutations predispose to these changes. An analogous SBS signature, again without biallelic BRCA2 inactivation, accompanies MGO accumulation and DNA damage in Kras-driven, Brca2-mutant murine pancreatic cancers and human breast cancers. MGO triggers BRCA2 proteolysis, temporarily disabling BRCA2's tumor suppressive functions in DNA repair and replication, causing functional haploinsufficiency. Intermittent MGO exposure incites episodic SBS mutations without permanent BRCA2 inactivation. Thus, a metabolic mechanism wherein MGO-induced BRCA2 haploinsufficiency transiently bypasses Knudson's two-hit requirement could link glycolysis activation by oncogenes, metabolic disorders, or dietary challenges to mutational signatures implicated in cancer evolution.

Identification of regulators of polyploidization presents therapeutic targets for treatment of AMKL.

The mechanism by which cells decide to skip mitosis to become polyploid is largely undefined. Here we used a high-content image-based screen to identify small-molecule probes that induce polyploidization of megakaryocytic leukemia cells and serve as perturbagens to help understand this process. Our study implicates five networks of kinases that regulate the switch to polyploidy. Moreover, we find that dimethylfasudil (diMF, H-1152P) selectively increased polyploidization, mature cell-surface marker expression, and apoptosis of malignant megakaryocytes. An integrated target identification approach employing proteomic and shRNA screening revealed that a major target of diMF is Aurora kinase A (AURKA). We further find that MLN8237 (Alisertib), a selective inhibitor of AURKA, induced polyploidization and expression of mature megakaryocyte markers in acute megakaryocytic leukemia (AMKL) blasts and displayed potent anti-AMKL activity in vivo. Our findings provide a rationale to support clinical trials of MLN8237 and other inducers of polyploidization and differentiation in AMKL.

Targeting hypoxia-inducible factor-1, for cancer treatment: Recent advances in developing small-molecule inhibitors from natural compounds.

Rapid progress in molecular cancer biology coupled with the discovery of novel oncology drugs has opened new horizons for cancer target discovery. As one of the crucial signaling pathways related to tumorigenesis, hypoxia-inducible factor-1 (HIF-1) coordinates the activity of many transcription factors and their downstream molecules that impact tumor growth and metastasis. Accumulating evidence suggests that the transcriptional responses to acute hypoxia are mainly attributable to HIF-1α. Moreover, the overexpression of HIF-1α in several solid cancers has been found to be strongly associated with poor prognosis. Thus, pharmacological targeting of the HIF-1 signaling pathways has been considered as a new strategy for cancer therapy in the recent years. Although over the past decade, tremendous efforts have been made in preclinical studies to develop new HIF-1 inhibitors from natural products (reservoirs of novel therapeutic agents), to date, these efforts have not been successfully translated into clinically available treatments. In this review, we provide new insights into the bio-pharmacological considerations for selecting natural compounds as potential HIF-1 inhibitors to accelerate anti-cancer drug development. In addition, we highlighted the importance of assessing the dependency of cancer on HIF1A to shortlist cancer types as suitable disease models. This may subsequently lead to new paradigms for discovering more HIF-1 inhibitors derived from natural products and facilitate the development of potent therapeutic agents targeting specific cancer types.

Clinical outcome and prognostic factors for Asian patients in Phase I clinical trials.

BACKGROUND: Patient selection is key in Phase I studies, and prognosis can be difficult to estimate in heavily pre-treated patients. Previous prognostic models like the Royal Marsden Hospital (RMH) score or using the neutrophil-lymphocyte ratio (NLR) have not been validated in current novel therapies nor in the Asian Phase I population. METHODS: We conducted a retrospective review of 414 patients with solid tumours participating in Phase I studies at our centre between October 2013 and December 2020. RESULTS: The RMH model showed poorer prognosis with increasing scores [RMH score 1, HR 1.28 (95% CI: 0.96-1.70); RMH score 2, HR 2.27 (95% CI: 1.62-3.17); RMH score 3, HR 4.14 (95% CI: 2.62-6.53)]. NLR did not improve the AUC of the model. Poorer ECOG status (ECOG 1 vs. 0: HR = 1.59 (95% CI = 1.24-2.04), P < 0.001) and primary tumour site (GI vs. breast cancer: HR = 3.06, 95% CI = 2.16-4.35, P < 0.001) were prognostic. CONCLUSIONS: We developed a NCIS prognostic score with excellent prognostic ability for both short-term and longer-term survival (iAUC: 0.71 [95% CI 0.65-0.76]), and validated the RMH model in the largest Asian study to date.

Extracellular vesicles, the cornerstone of next-generation cancer diagnosis?

Cancer has risen up to be a major cause of mortality worldwide over the past decades. Despite advancements in cancer screening and diagnostics, a significant number of cancers are still diagnosed at a late stage with poor prognosis. Hence, the discovery of reliable and accurate methods to diagnose cancer early would be of great help in reducing cancer mortality. Extracellular vesicles (EVs) are phospholipid vesicles found in many biofluids and are released by almost all types of cells. In recent years, using EVs as cancer biomarkers has garnered attention as a novel technique of cancer diagnosis. Compared with traditional tissue biopsy, there are many advantages that this novel diagnostic tool presents - it is less invasive, detects early-stage asymptomatic cancers, and allows for monitoring of tumour progression. As such, EV biomarkers have great potential in improving the diagnostic accuracy of cancers and guiding subsequent therapeutic decisions. Efficient isolation and accurate characterization of EVs are essential for reliable outcomes of clinical application. However, these are complicated by the size and biomolecular diversity of EVs. In this review, we present an analysis and evaluation of the current techniques of EV isolation and characterization, as well as discuss the potential EV biomarkers for specific types of cancer. Taken together, EV biomarkers have a lot of potential as a novel method in cancer diagnostics and diagnosis. However, more work is still needed to streamline the purification, characterization and biomarker identification process to ensure optimal outcomes for patients.

Risk factors for immune-related adverse events from anti-PD-1 or anti-PD-L1 treatment in an Asian cohort of nonsmall cell lung cancer patients.

Immune-related adverse events (IrAEs) of immune checkpoint inhibitors (ICIs) can be serious and unpredictable. We examine the incidence rate and risk factors for IrAEs in an Asian cohort of nonsmall cell lung cancer (NSCLC) patients treated with immunotherapy. Between June 2014 and August 2020, we retrospectively analysed IrAEs in NSCLC patients treated with anti-PD-1 or anti-PD-L1 inhibitors at the National University Cancer Institute, Singapore. A Poisson regression model was used to estimate the effect of risk factors on incidence rate of any grade IrAEs. One hundred and forty-one patients were enrolled. Median age was 63. Majority were male (67%) with Eastern Cooperative Oncology Group (ECOG) PS 0-1 (77%). More than half (56%) received pembrolizumab. Eleven percent harboured epidermal growth factor receptor (EGFR) mutation. Eighteen percent received concomitant chemotherapy. Median number of cycles was 4, and median duration of treatment was 2.1 months. IrAEs were seen in 71 (50.4%) patients, with an incidence rate of 99 events per 1000 person-months. Fatigue (25%), rash (10.5%) and pneumonitis (7.9%) were the most common IrAEs. Twenty out of 152 IrAEs (13.2%) were Grade 3 or higher in severity: most common being pneumonitis (5.3%), fatigue (3.3%) and transaminitis (1.3%). Multivariable analysis demonstrated that concomitant chemotherapy use, higher BMI and presence of EGFR mutation are significant predictors for IrAEs (P < .0001; P = .016; P = .007). Our findings can help guide risk stratification and monitoring of IrAEs among NSCLC patients on immunotherapy.

Phase I study of expanded natural killer cells in combination with cetuximab for recurrent/metastatic nasopharyngeal carcinoma.

BACKGROUND: Nasopharyngeal carcinoma (NPC) cells express high levels of epidermal growth factor receptor (EGFR). Cetuximab is an anti-EGFR monoclonal antibody that promotes natural killer (NK) cell-mediated antibody-dependent cellular cytotoxicity (ADCC) via engagement of CD16. We studied safety and efficacy of combining cetuximab with autologous expanded NK cells in patients with recurrent and/or metastatic NPC who had failed at least two prior lines of chemotherapy. METHODS: Seven subjects (six patients) received cetuximab every 3 weeks (six doses maximum) in the pre-trial phase. Autologous NK cells, expanded by co-culture with irradiated K562-mb15-41BBL cells, were then infused on the day after administration of cetuximab. Primary and secondary objectives were to determine safety of this combination therapy and to assess tumor responses, respectively. RESULTS: Median NK cell expansion from peripheral blood mononucleated cells after 10 days of culture with K562-mb15-41BBL was 274-fold (range, 36-534, n = 10), and the median expression of CD16 was 98.4% (range, 67.8-99.7%). Skin rash, the commonest side effect of cetuximab in the pre-trial phase, was not exacerbated by NK cell infusion. No intolerable side effects were observed. Stable disease was observed in four subjects and progressive disease in three subjects. Three patients who received NK cells twice had time to disease progression of 12, 13, and 19 months. CONCLUSION: NK cells with high ADCC potential can be expanded from patients with heavily pre-treated NPC. The safety profile and encouraging clinical responses observed after combining these cells with cetuximab warrant further studies of this approach. (clinicalTrials.gov NCT02507154, 23/07/2015). PRECIS: Engaging NK cell-mediated ADCC using cetuximab plus autologous NK cells in EGFR-positive NPC was well tolerated among heavily pre-treated recurrent NPC. Promising results were observed with 3 out of 7 subjects demonstrating durable stable disease.

Epstein-Barr virus-induced ectopic CD137 expression helps nasopharyngeal carcinoma to escape immune surveillance and enables targeting by chimeric antigen receptors.

Non-keratinizing nasopharyngeal carcinoma (NPC) is a malignancy with a poor prognosis for relapsing patients and those with metastatic disease. Here, we identify a novel disease mechanism of NPC which may be its Achilles' heel that makes it susceptible to immunotherapy. CD137 is a potent costimulatory receptor on activated T cells, and CD137 agonists strongly enhance anti-tumor immune responses. A negative feedback mechanism prevents overstimulation by transferring CD137 from T cells to CD137 ligand (CD137L)-expressing antigen presenting cells (APC) during cognate interaction, upon which the CD137-CD137L complex is internalized and degraded. We found ectopic expression of CD137 on 42 of 122 (34.4%) NPC cases, and that CD137 is induced by the Epstein-Barr virus latent membrane protein (LMP) 1. CD137 expression enables NPC to hijack the inbuilt negative feedback mechanism to downregulate the costimulatory CD137L on APC, facilitating its escape from immune surveillance. Further, the ectopically expressed CD137 signals into NPC cells via the p38-MAPK pathway, and induces the expression of IL-6, IL-8 and Laminin γ2. As much as ectopic CD137 expression may support the growth and spread of NPC, it may be a target for its immunotherapeutic elimination. Natural killer cells that express a CD137-specific chimeric antigen receptor induce death in CD137+ NPC cells, in vitro, and in vivo in a murine xenograft model. These data identify a novel immune escape mechanism of NPC, and lay the foundation for an urgently needed immunotherapeutic approach for NPC.

Dendritic cell therapy with CD137L-DC-EBV-VAX in locally recurrent or metastatic nasopharyngeal carcinoma is safe and confers clinical benefit.

INTRODUCTION: Epstein-Barr virus (EBV) is associated with nasopharyngeal carcinoma (NPC), and provides a target for a dendritic cell (DC) vaccine. CD137 ligand (CD137L) expressed on antigen presenting cells, costimulates CD137-expressing T cells, and reverse CD137L signaling differentiates monocytes to CD137L-DC, a type of DC, which is more potent than classical DC in stimulating T cells. METHODS: In this phase I study, patients with locally recurrent or metastatic NPC were administered CD137L-DC pulsed with EBV antigens (CD137L-DC-EBV-VAX). RESULTS: Of the 12 patients treated, 9 received full 7 vaccine doses with a mean administered cell count of 23.9 × 106 per dose. Treatment was well tolerated with only 4 cases of grade 1 related adverse events. A partial response was obtained in 1 patient, and 4 patients are still benefitting from a progression free survival (PFS) of currently 2-3 years. The mean pre-treatment neutrophil: lymphocyte ratio was 3.4 and a value of less than 3 was associated with prolonged median PFS. Progressors were characterized by a high frequency of naïve T cells but a low frequency of CD8+ effector T cells while patients with a clinical benefit (CB) had a high frequency of memory T cells. Patients with CB had lower plasma EBV DNA levels, and a reduction after vaccination. CONCLUSION: CD137L-DC-EBV-VAX was well tolerated. The use of CD137L-DC-EBV-VAX is demonstrated to be safe. Consistent results were obtained from all 12 patients, indicating that CD137L-DC-EBV-VAX induces an anti-EBV and anti-NPC immune response, and warranting further studies in patients post effective chemotherapy. PRECIS: The first clinical testing of CD137L-DC, a new type of monocyte-derived DC, finds that CD137L-DC are safe, and that they can induce an immune response against Epstein-Barr virus-associated nasopharyngeal carcinoma that leads to tumor regression or prevents tumor progression.

Immunohistochemistry study of tumor vascular normalization and anti-angiogenic effects of sunitinib versus bevacizumab prior to dose-dense doxorubicin/cyclophosphamide chemotherapy in HER2-negative breast cancer.

PURPOSE: Tumor angiogenesis controlled predominantly by vascular endothelial growth factor and its receptor (VEGF-VEGFR) interaction plays a key role in the growth and propagation of cancer cells. However, the newly formed network of blood vessels is disorganized and leaky. Pre-treatment with anti-angiogenic agents can "normalize" the tumor vasculature allowing effective intra-tumoral delivery of standard chemotherapy. Immunohistochemistry (IHC) analysis was applied to investigate and compare the vascular normalization and anti-angiogenic effects of two commonly used anti-angiogenic agents, Sunitinib and Bevacizumab, administered prior to chemotherapy in HER2-negative breast cancer patients. METHODS: This prospective clinical trial enrolled 38 patients into a sunitinib cohort and 24 into a bevacizumab cohort. All received 4 cycles of doxorubicin/cyclophosphamide chemotherapy and pre-treatment with either sunitinib or bevacizumab. Tumor biopsies were obtained at baseline, after cycle 1 (C1) and cycle 4 (C4) of chemotherapy. IHC was performed to assess the tumor vascular normalization index (VNI), lymphatic vessel density (LVD), Ki67 proliferation index and expression of tumor VEGFR2. RESULTS: In comparison to Bevacizumab, Sunitinib led to a significant increase in VNI post-C1 and C4 (p < 0.001 and 0.001) along with decrease in LVD post-C1 (p = 0.017). Both drugs when combined with chemotherapy resulted in significant decline in tumor proliferation after C1 and C4 (baseline vs post-C4 Ki67 index p = 0.006 for Sunitinib vs p = 0.021 for Bevacizumab). Bevacizumab resulted in a significant decrease in VEGFR2 expression post-C1 (p = 0.004). CONCLUSION: Sunitinib, in comparison to Bevacizumab showed a greater effect on tumor vessel modulation and lymphangiogenesis suggesting that its administration prior to chemotherapy might result in improved drug delivery. TRIAL REGISTRY: ClinicalTrials.gov: NCT02790580 (first posted June 6, 2016).

Weekly versus tri-weekly paclitaxel with carboplatin for first-line treatment in women with epithelial ovarian cancer.

BACKGROUND: Epithelial ovarian cancer is the sixth most common cancer worldwide: 295,414 new cases were diagnosed in 2018, with 184,799 deaths. The lack of an effective screening strategy has led to the majority of women being diagnosed at an advanced stage. For these women, intravenous carboplatin combined with paclitaxel for six cycles is widely accepted as the standard first-line treatment for epithelial ovarian cancer, in combination with debulking surgery. However, there is conflicting evidence regarding the optimal dosing schedule of paclitaxel when combined with carboplatin in this setting. OBJECTIVES: To compare the efficacy and tolerability of intravenous weekly paclitaxel with that of tri-weekly paclitaxel, in combination with intravenous carboplatin, as first-line treatment for epithelial ovarian cancer (defined as epithelial ovarian, primary peritoneal and fallopian tube cancer). SEARCH METHODS: We searched CENTRAL, MEDLINE, and Embase databases for relevant studies up to 15 November 2021, using keywords and MeSH terms. We additionally handsearched conference libraries, online clinical trial databases and screened through lists of retrieved references. SELECTION CRITERIA: We Included randomised controlled trials (RCTs) comparing weekly paclitaxel in combination with carboplatin versus tri-weekly paclitaxel in combination with carboplatin, for treatment of newly-diagnosed epithelial ovarian cancer. DATA COLLECTION AND ANALYSIS: We used the hazard ratio (HR) to estimate the primary efficacy outcomes progression-free (PFS) and overall survival (OS). We used the risk ratio (RR) to estimate the primary toxicity outcome of severe neutropenia and secondary outcomes of quality of life (QoL) and treatment-related adverse events. Two review authors independently selected studies, extracted data, and assessed risk of bias, using standard Cochrane methodological procedures. We included individual participant data (IPD) from one of the included studies, ICON-8, provided by the study team. We analysed data using a random-effects model in Review Manager 5.4 software. Additionally, we reconstructed IPD for PFS and OS data from published Kaplan-Meier curves from all studies and subsequently pooled these to analyse the two primary efficacy outcomes. MAIN RESULTS: From 2469 records, we identified four eligible RCTs with data for 3699 participants. All eligible studies were included in the main meta-analysis and reported on PFS and OS. There was likely a slight improvement in PFS when paclitaxel was dosed weekly compared to tri-weekly (HR 0.89, 95% confidence interval (CI) 0.81 to 0.98; 4 studies, 3699 participants; moderate-certainty evidence). We found little to no improvement in OS when paclitaxel was dosed weekly compared to tri-weekly (HR 0.92, 95% CI 0.79 to 1.06; 4 studies, 3699 participants; high-certainty evidence). There was likely little to no difference in high-grade (grade 3 or 4) neutropenia when paclitaxel was dosed weekly compared to tri-weekly (RR 1.11, 95% CI 0.86 to 1.43; 4 studies, 3639 participants; moderate-certainty evidence). However, weekly paclitaxel increased high-grade (grade 3 or 4) anaemia when compared to tri-weekly dosing (RR 1.57, 95% CI 1.12 to 2.20; 4 studies, 3639 participants; high-certainty evidence). There may be little to no difference in high-grade neuropathy when paclitaxel was dosed weekly compared to tri-weekly (RR 1.12, 95% CI 0.64 to 1.94; 4 studies, 3639 participants; low-certainty evidence). The overall risk of detection bias and performance bias was low for OS, but was unclear for other outcomes, as treatments were not blinded. The risk of bias in other domains was low or unclear. We note that OS data were immature for three of the included studies (GOG-0262, ICON-8 and MITO-7). AUTHORS' CONCLUSIONS: Weekly paclitaxel combined with carboplatin for first-line treatment of epithelial ovarian cancer likely improves PFS slightly (moderate-certainty evidence) but not OS (high-certainty evidence), compared to tri-weekly paclitaxel combined with carboplatin. However, this was associated with increased risk for high-grade anaemia, treatment discontinuation, dose delays and dose omissions (high- to low-certainty evidence). Our findings may not apply to women receiving bevacizumab in first-line therapy, those receiving treatment in the neo-adjuvant setting, or those with rare subtypes of clear cell or mucinous ovarian cancer.

Low-dose pembrolizumab in the treatment of advanced non-small cell lung cancer.

A dose of 200 mg 3-weekly of pembrolizumab was approved by the Food and Drug Administration (FDA) as treatment for advanced non-small cell lung cancer (NSCLC) without oncogenic drivers. This is despite evidence showing no difference in efficacy with 2 mg/kg. Our study aimed to assess the efficacy of a lower fixed dose of 100 mg, which is closer to 2 mg/kg weight-based dose in an average-sized Asian patient. All patients receiving pembrolizumab for advanced NSCLC from January 2016 to March 2020 in National University Hospital, Singapore, were included in this retrospective observational study. The effect of pembrolizumab 100 mg (Pem100) vs 200 mg (Pem200) upon survival outcomes, toxicity and cost were examined. One hundred fourteen patients received pembrolizumab. Sixty-five (57%) and 49 (43%) received Pem100 and Pem200, respectively. There was no difference in progression-free survival (PFS) and overall survival (OS) between Pem100 vs Pem200 as a single agent (PFS: 6.8 vs 4.2 months, hazard ratio [HR] 0.72, 95% confidence interval [CI] 0.36-1.46, P = .36; 9 month OS: 58% vs 63%, HR 1.08, 95% CI 0.48-2.41, P = .86) and when combined with chemotherapy (9-month PFS: 60% vs 50%, HR0.84, 95% CI 0.34-2.08, P = .71; 9-month OS: 85% vs 58%, HR 0.27, 95% CI 0.062-1.20, P = .09). No significant difference in response rate or ≥G3 immune-related toxicities between Pem100 and Pem200 was observed. A cost minimisation analysis evaluating the degree of cost savings related to drug costs estimated a within study cost saving of SGD4,290,912 and cost saving per patient of SGD39,942 in the Pem100 group. A 100 mg of pembrolizumab appears to be effective with reduction in cost. A randomised trial should be done to investigate a lower dose of pembrolizumab.

MELK mediates the stability of EZH2 through site-specific phosphorylation in extranodal natural killer/T-cell lymphoma.

Oncogenic EZH2 is overexpressed and extensively involved in the pathophysiology of different cancers including extranodal natural killer/T-cell lymphoma (NKTL). However, the mechanisms regarding EZH2 upregulation is poorly understood, and it still remains untargetable in NKTL. In this study, we examine EZH2 protein turnover in NKTL and identify MELK kinase as a regulator of EZH2 ubiquitination and turnover. Using quantitative mass spectrometry analysis, we observed a MELK-mediated increase of EZH2 S220 phosphorylation along with a concomitant loss of EZH2 K222 ubiquitination, suggesting a phosphorylation-dependent regulation of EZH2 ubiquitination. MELK inhibition through both chemical and genetic means led to ubiquitination and destabilization of EZH2 protein. Importantly, we determine that MELK is upregulated in NKTL, and its expression correlates with EZH2 protein expression as determined by tissue microarray derived from NKTL patients. FOXM1, which connected MELK to EZH2 signaling in glioma, was not involved in mediating EZH2 ubiquitination. Furthermore, we identify USP36 as the deubiquitinating enzyme that deubiquitinates EZH2 at K222. These findings uncover an important role of MELK and USP36 in mediating EZH2 stability in NKTL. Moreover, MELK overexpression led to decreased sensitivity to bortezomib treatment in NKTL based on deprivation of EZH2 ubiquitination. Therefore, modulation of EZH2 ubiquitination status by targeting MELK may be a new therapeutic strategy for NKTL patients with poor bortezomib response.

Intracellular vincristine levels in lymphoblasts affect treatment outcome in childhood B-lymphoblastic leukaemia: Ma-Spore ALL 2010 study.

AIMS: Vincristine (VCR) is a key drug in the successful multidrug chemotherapy for childhood acute lymphoblastic leukaemia (ALL). However, it remains unclear how VCR pharmacokinetics affects its antileukaemic efficacy. The objective of this study is to explore the VCR pharmacokinetic parameters and intracellular VCR levels in an up-front window of Ma-Spore ALL 2010 (MS2010) study. METHODS: We randomised 429 children with newly diagnosed ALL to 15-minute vs 3-hour infusion for the first dose of VCR to study if prolonging the first dose of VCR infusion improved response. In a subgroup of 115 B-ALL and 20 T-ALL patients, we performed VCR plasma (n = 135 patients) and intracellular (n = 66 patients) pharmacokinetic studies. The correlations between pharmacokinetic parameters and intracellular VCR levels with early treatment response, final outcome and ABCB1 genotypes were analysed. RESULTS: There was no significant difference between 15-minute and 3-hour infusion schedules in median Day 8 peripheral or bone marrow blast response. Plasma VCR pharmacokinetic parameters did not predict outcome. However, in B-ALL, Day 33 minimal residual disease (MRD) negative patients and patients in continuous complete remission had significantly higher median intracellular VCR24h levels (P = .03 and P = .04, respectively). The median VCR24h intracellular levels were similar among the common genetic subtypes of ALL (P = .4). Patients homozygous for wild-type ABCB1 2677GG had significantly higher median intracellular VCR24h (P = .04) than 2677TT. CONCLUSION: We showed that in childhood B-ALL, the intracellular VCR24h levels in lymphoblasts affected treatment outcomes. The intracellular VCR24h level was independent of leukaemia subtype but dependent on host ABCB1 G2677T genotype.

Targetable BET proteins- and E2F1-dependent transcriptional program maintains the malignancy of glioblastoma.

Competitive BET bromodomain inhibitors (BBIs) targeting BET proteins (BRD2, BRD3, BRD4, and BRDT) show promising preclinical activities against brain cancers. However, the BET protein-dependent glioblastoma (GBM)-promoting transcriptional network remains elusive. Here, with mechanistic exploration of a next-generation chemical degrader of BET proteins (dBET6), we reveal a profound and consistent impact of BET proteins on E2F1- dependent transcriptional program in both differentiated GBM cells and brain tumor-initiating cells. dBET6 treatment drastically reduces BET protein genomic occupancy, RNA-Pol2 activity, and permissive chromatin marks. Subsequently, dBET6 represses the proliferation, self-renewal, and tumorigenic ability of GBM cells. Moreover, dBET6-induced degradation of BET proteins exerts superior antiproliferation effects compared to conventional BBIs and overcomes both intrinsic and acquired resistance to BBIs in GBM cells. Our study reveals crucial functions of BET proteins and provides the rationale and therapeutic merits of targeted degradation of BET proteins in GBM.

The pleiotropic role of transcription factor STAT3 in oncogenesis and its targeting through natural products for cancer prevention and therapy.

Signal transducer and activator of transcription 3 (STAT3) is one of the crucial transcription factors, responsible for regulating cellular proliferation, cellular differentiation, migration, programmed cell death, inflammatory response, angiogenesis, and immune activation. In this review, we have discussed the classical regulation of STAT3 via diverse growth factors, cytokines, G-protein-coupled receptors, as well as toll-like receptors. We have also highlighted the potential role of noncoding RNAs in regulating STAT3 signaling. However, the deregulation of STAT3 signaling has been found to be associated with the initiation and progression of both solid and hematological malignancies. Additionally, hyperactivation of STAT3 signaling can maintain the cancer stem cell phenotype by modulating the tumor microenvironment, cellular metabolism, and immune responses to favor drug resistance and metastasis. Finally, we have also discussed several plausible ways to target oncogenic STAT3 signaling using various small molecules derived from natural products.

A randomized phase II trial evaluating the addition of low dose, short course sunitinib to docetaxel in advanced solid tumours.

BACKGROUND: We previously reported that low-dose, short-course sunitinib prior to neoadjuvant doxorubicin-cyclophosphamide (AC) normalised tumour vasculature and improved perfusion, but resulted in neutropenia and delayed subsequent cycles in breast cancer patients. This study combined sunitinib with docetaxel, which has an earlier neutrophil nadir than AC. METHODS: Patients with advanced solid cancers were randomized 1:1 to 3-weekly docetaxel 75 mg/m2, with or without sunitinib 12.5 mg daily for 7 days prior to docetaxel, stratified by primary tumour site. Primary endpoints were objective-response (ORR:CR + PR) and clinical-benefit rate (CBR:CR + PR + SD); secondary endpoints were toxicity and progression-free-survival (PFS). RESULTS: We enrolled 68 patients from 2 study sites; 33 received docetaxel-sunitinib and 35 docetaxel alone, with 33 breast, 25 lung and 10 patients with other cancers. There was no difference in ORR (30.3% vs 28.6%, p = 0.432, odds-ratio [OR] 1.10, 95% CI 0.38-3.18); CBR was lower in the docetaxel-sunitinib arm (48.5% vs 71.4%, p = 0.027 OR 0.37, 95% CI 0.14-1.01). Median PFS was shorter in the docetaxel-sunitinib arm (2.9 vs 4.9 months, hazard-ratio [HR] 2.00, 95% CI 1.15-3.48, p = 0.014) overall, as well as in breast (4.2 vs 5.6 months, p = 0.048) and other cancers (2.0 vs 5.3 months, p = 0.009), but not in lung cancers (2.9 vs 4.1 months, p = 0.597). Median OS was similar in both arms overall (9.9 vs 10.5 months, HR 0.92, 95% CI 0.51-1.67, p = 0.789), and in the breast (18.9 vs 25.8 months, p = 0.354), lung (7.0 vs 6.7 months, p = 0.970) and other cancers (4.5 vs 8.8 months, p = 0.449) subgroups. Grade 3/4 haematological toxicities were lower with docetaxel-sunitinib (18.2% vs 34.3%, p = 0.132), attributed to greater discretionary use of prophylactic G-CSF (90.9% vs 63.0%, p = 0.024). Grade 3/4 non-haematological toxicities were similar (12.1% vs 14.3%, p = 0.792). CONCLUSIONS: The addition of sunitinib to docetaxel was well-tolerated but did not improve outcomes. The possible negative impact in metastatic breast cancer patients is contrary to results of adding sunitinib to neoadjuvant AC. These negative results suggest that the intermittent administration of sunitinib in the current dose and schedule with docetaxel in advanced solid tumours, particularly breast cancers, is not beneficial. TRIAL REGISTRATION: The study was registered ( NCT01803503 ) prospectively on clinicaltrials.gov on 4th March 2013.

A unique CDK4/6 inhibitor: Current and future therapeutic strategies of abemaciclib.

Cell cycle dysregulation, characterised by aberrant activation of cyclin dependent kinases (CDKs), is a hallmark of cancer. After years of research on the first and second generations of less selective CDK inhibitors with unfavourable clinical activity and toxicity profiles, CDK4/6 inhibitors become the first and only class of highly specific CDK inhibitors being approved for cancer treatment to date. CDK4/6 inhibitors have transformed the treatment paradigm of estrogen receptor-positive (ER+) breast cancer, dramatically improving the survival outcomes of these patients when incorporated with conventional endocrine therapies in both the first and later-line settings. Currently, the efficacies of CDK4/6 inhibitors in other breast cancer subtypes and cancers are being actively explored. All three CDK4/6 inhibitors have demonstrated very similar clinical efficacies. However, being the least similar structurally, abemaciclib is the only CDK4/6 inhibitor with single agent activity in refractory metastatic ER + breast cancer, the ability to cross the blood brain barrier efficiently, and a distinct toxicity profile of lower myelosuppression such that it can be dosed continuously. Here, we further discuss the distinguishing features of abemaciclib as compared to the other two CDK4/6 inhibitors, palbociclib and ribociclib. Besides being the most potent inhibitor of CDK4/6, abemaciclib exhibits a wider selectivity towards other CDKs and kinases, and functions through additional mechanisms of action besides inducing G1 cell cycle arrest, in a dose dependent manner. Hence, abemaciclib has the potential to act independently of the CDK4/6-cyclin D-RB pathway, resulting in crucial implications on the possibly expanded clinical indications and predictive biomarkers of abemaciclib, in contrast to the other CDK4/6 inhibitors. The current status of preclinical evidence and clinical studies of abemaciclib as a single agent and in combination treatment in breast and other cancers, together with its potential predictive biomarkers, is also summarised in this review.

Bevacizumab Augments the Antitumor Efficacy of Infigratinib in Hepatocellular Carcinoma.

The fibroblast growth factor (FGF) signaling cascade is one of the key signaling pathways in hepatocellular carcinoma (HCC). FGF has been shown to augment vascular endothelial growth factor (VEGF)-mediated HCC development and angiogenesis, as well as to potentially lead to resistance to VEGF/VEGF receptor (VEGFR)-targeted agents. Thus, novel agents targeting FGF/FGF receptor (FGFR) signaling may enhance and/or overcome de novo or acquired resistance to VEGF-targeted agents in HCC. Mice bearing high- and low-FGFR tumors were treated with Infigratinib (i.e., a pan-FGFR kinase inhibitor) and/or Bevacizumab (i.e., an angiogenesis inhibitor). The antitumor activity of both agents was assessed individually or in combination. Tumor vasculature, intratumoral hypoxia, and downstream targets of FGFR signaling pathways were also investigated. Infigratinib, when combined with Bevacizumab, exerted a synergistic inhibitory effect on tumor growth, invasion, and lung metastasis, and it significantly improved the overall survival of mice bearing FGFR-dependent HCC. Infigratinib/Bevacizumab promoted apoptosis, inhibited cell proliferation concomitant with upregulation of p27, and reduction in the expression of FGFR2-4, p-FRS-2, p-ERK1/2, p-p70S6K/4EBP1, Cdc25C, survivin, p-Cdc2, and p-Rb. Combining Infigratinib/Bevacizumab may provide therapeutic benefits for a subpopulation of HCC patients with FGFR-dependent tumors. A high level of FGFR-2/3 may serve as a potential biomarker for patient selection to Infigratinib/Bevacizumab.

Targeting Metabolism in Cancer Cells and the Tumour Microenvironment for Cancer Therapy.

Targeting altered tumour metabolism is an emerging therapeutic strategy for cancer treatment. The metabolic reprogramming that accompanies the development of malignancy creates targetable differences between cancer cells and normal cells, which may be exploited for therapy. There is also emerging evidence regarding the role of stromal components, creating an intricate metabolic network consisting of cancer cells, cancer-associated fibroblasts, endothelial cells, immune cells, and cancer stem cells. This metabolic rewiring and crosstalk with the tumour microenvironment play a key role in cell proliferation, metastasis, and the development of treatment resistance. In this review, we will discuss therapeutic opportunities, which arise from dysregulated metabolism and metabolic crosstalk, highlighting strategies that may aid in the precision targeting of altered tumour metabolism with a focus on combinatorial therapeutic strategies.