Loss of the INK4a/ARF/INK4b locus on chromosome 9p21 is among the most frequent cytogenetic events in human cancer. The products of the locus—p15INK4b, p16INK4a, and ARF—play widespread and ...independent roles in tumor suppression. Recent data also suggest that expression of p16INK4a induces an age-dependent decrease in the proliferative capacity of certain tissue-specific stem cells and unipotent progenitors. Here, we discuss the regulation and role of p16INK4a, ARF, and p15INK4b in cancer and aging.
Germline inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene causes the von Hippel-Lindau hereditary cancer syndrome, and somatic mutations of this gene have been linked to the ...development of sporadic hemangioblastomas and clear-cell renal carcinomas. The VHL tumor suppressor protein (pVHL), through its oxygen-dependent polyubiquitylation of hypoxia-inducible factor (HIF), plays a central role in the mammalian oxygen-sensing pathway. This interaction between pVHL and HIF is governed by post-translational prolyl hydroxylation of HIF in the presence of oxygen by a conserved family of Egl-nine (EGLN) enzymes. In the absence of pVHL, HIF becomes stabilized and is free to induce the expression of its target genes, many of which are important in regulating angiogenesis, cell growth, or cell survival. Moreover, preliminary data indicate that HIF plays a critical role in pVHL-defective tumor formation, raising the possibility that drugs directed against HIF or its downstream targets (such as vascular endothelial growth factor) might one day play a role in the treatment of hemangioblastoma and renal cell carcinoma. On the other hand, clear genotype-phenotype correlations are emerging in VHL disease and can be rationalized if pVHL has functions separate from its control of HIF.
Combination chemotherapy is a common practice in clinical management of malignancy. Synergistic therapeutic outcome is only achieved when tumor cells are exposed to cells in an optimal ratio. ...However, due to diverse physicochemical properties of drugs, no free drug cocktails or nanomaterials are capable of co‐loading and co‐delivering drugs at an optimal ratio. Herein, we develop a novel nano‐platform with precise ratiometric co‐loading and co‐delivery of two hydrophilic drugs for synergistic anti‐tumor effects. Based on previous work, we utilize a solvent displacement method to ratiometrically load dioleoyl phosphatidic acid (DOPA)‐gemcitabine monophosphate (GMP) and DOPA coated cisplatin‐precipitate nanocores into the same PLGA NP. These cores are designed to have similar hydrophobic surface properties. GMP and cisplatin are engineered into PLGA NP at an optimal synergistic ratio (5:1, mol:mol) with over 70% encapsulation efficiency and were ratiometrically taken up by tumor cells in vitro and in vivo. These PLGA NP exhibit synergistic anti‐cancer effects in a stroma‐rich bladder tumor model. A single injection of dual drugs in PLGA NP can significantly inhibit tumor growth. This nanomaterial‐system solves problems related to ratiometric co‐loading and co‐delivery of different hydrophilic moieties and provides possibilities for co‐loading hydrophilic drugs with hydrophobic drugs for combination therapy.
A novel nano‐platform with ratiometric loading and delivery of multiple hydrophilic drug moieties is demonstrated. Hydrophilic cisplatin and gemcitabine monophosphate are standardized to a similar hydrophobicity through loading into lipid‐coated calcium phosphate and cisplatin cores, respectively. Precise ratio‐controlled loading and delivery is achieved by incorporating these cores into PLGA NPs. These ratiometric combinations lead to the maximal synergistic anticancer effect.
Clear-cell renal cell carcinoma tumors with an enhancer demethylator phenotype (TED) harbor a worse prognosis and derive less clinical benefit from immunotherapy. The TED phenotype may help predict ...immunotherapy resistance. See related article by Lu et al., p. 1279.
Despite recent therapeutic gains in the treatment of advanced bladder cancer, the overall survival in patients with metastatic disease remains poor and further therapeutic discovery is needed. ...Advanced bladder cancer is a molecularly heterogeneous disease, and the identification of driver genetic alterations has led to effective targeted therapeutic agents, such as fibroblast growth factor receptor (FGFR) inhibitors. In this issue of the JCI, Bekele et al. identify a subtype of muscle-invasive bladder cancer (MIBC) that harbors RAF1 amplification. The authors showed that RAF1 inhibition, with pan-RAF inhibitors, and the combination of RAF1 inhibition with MEK inhibition were efficacious in preclinical models harboring RAF1 amplifications as well as in tumors with HRAS and NRAS mutations. This study highlights RAF1 amplification as a driver event in bladder cancer and establishes the central role of the MAPK pathway in bladder tumorigenesis.
We sought to define whether there are intrinsic molecular subtypes of high-grade bladder cancer. Consensus clustering performed on gene expression data from a meta-dataset of high-grade, ...muscle-invasive bladder tumors identified two intrinsic, molecular subsets of high-grade bladder cancer, termed "luminal" and "basal-like," which have characteristics of different stages of urothelial differentiation, reflect the luminal and basal-like molecular subtypes of breast cancer, and have clinically meaningful differences in outcome. A gene set predictor, bladder cancer analysis of subtypes by gene expression (BASE47) was defined by prediction analysis of microarrays (PAM) and accurately classifies the subtypes. Our data demonstrate that there are at least two molecularly and clinically distinct subtypes of high-grade bladder cancer and validate the BASE47 as a subtype predictor. Future studies exploring the predictive value of the BASE47 subtypes for standard of care bladder cancer therapies, as well as novel subtype-specific therapies, will be of interest.
Abstract Nucleoside analogs are a significant class of anti-cancer agent. As prodrugs, they terminate the DNA synthesis upon transforming to their active triphosphate metabolites. We have ...encapsulated a biologically activate nucleotide analog (i.e. gemcitabine triphosphate (GTP)), instead of the nucleoside (i.e. gemcitabine) derivative, into a novel Lipid/Calcium/Phosphate nanoparticle (LCP) platform. The therapeutic efficacy of LCP-formulated GTP was evaluated in a panel of human non-small-cell lung cancer (NSCLC) and human pancreatic cancer models after systemic administrations. GTP-loaded LCPs induced cell death and arrested the cell cycle in the S phase. In vivo efficacy studies showed that intravenously injected GTP-loaded LCPs triggered effective apoptosis of tumor cells, significant reduction of tumor cell proliferation and cell cycle progression, leading to dramatic inhibition of tumor growth, with little in vivo toxicity. Broadly speaking, the current study offers preclinical proof-of-principle that many active nucleotide or phosphorylated nucleoside analogs could be encapsulated in the LCP nanoplatform and delivered systemically for a wide variety of therapeutic applications.
The ability to non-invasively monitor tumor-infiltrating T cells in vivo could provide a powerful tool to visualize and quantify tumor immune infiltrates. For non-invasive evaluations in vivo, an ...anti-CD3 mAb was modified with desferrioxamine (DFO) and radiolabeled with zirconium-89 (Zr-89 or 89Zr). Radiolabeled 89Zr-DFO-anti-CD3 was tested for T cell detection using positron emission tomography (PET) in both healthy mice and mice bearing syngeneic bladder cancer BBN975. In vivo PET/CT and ex vivo biodistribution demonstrated preferential accumulation and visualization of tracer in the spleen, thymus, lymph nodes, and bone marrow. In tumor bearing mice, 89Zr-DFO-anti-CD3 demonstrated an 11.5-fold increase in tumor-to-blood signal compared to isotype control. Immunological profiling demonstrated no significant change to total T cell count, but observed CD4+ T cell depletion and CD8+ T cell expansion to the central and effector memory. This was very encouraging since a high CD8+ to CD4+ T cell ratio has already been associated with better patient prognosis. Ultimately, this anti-CD3 mAb allowed for in vivo imaging of homeostatic T cell distribution, and more specifically tumor-infiltrating T cells. Future applications of this radiolabeled mAb against CD3 could include prediction and monitoring of patient response to immunotherapy.
Muscle-invasive bladder cancer (MIBC) is a molecularly diverse disease with heterogeneous clinical outcomes. Several molecular classifications have been proposed, but the diversity of their subtype ...sets impedes their clinical application.
To achieve an international consensus on MIBC molecular subtypes that reconciles the published classification schemes.
We used 1750 MIBC transcriptomic profiles from 16 published datasets and two additional cohorts.
We performed a network-based analysis of six independent MIBC classification systems to identify a consensus set of molecular classes. Association with survival was assessed using multivariable Cox models.
We report the results of an international effort to reach a consensus on MIBC molecular subtypes. We identified a consensus set of six molecular classes: luminal papillary (24%), luminal nonspecified (8%), luminal unstable (15%), stroma-rich (15%), basal/squamous (35%), and neuroendocrine-like (3%). These consensus classes differ regarding underlying oncogenic mechanisms, infiltration by immune and stromal cells, and histological and clinical characteristics, including outcomes. We provide a single-sample classifier that assigns a consensus class label to a tumor sample’s transcriptome. Limitations of the work are retrospective clinical data collection and a lack of complete information regarding patient treatment.
This consensus system offers a robust framework that will enable testing and validation of predictive biomarkers in future prospective clinical trials.
Bladder cancers are heterogeneous at the molecular level, and scientists have proposed several classifications into sets of molecular classes. While these classifications may be useful to stratify patients for prognosis or response to treatment, a consensus classification would facilitate the clinical use of molecular classes. Conducted by multidisciplinary expert teams in the field, this study proposes such a consensus and provides a tool for applying the consensus classification in the clinical setting.
An international consortium of bladder cancer expert teams establishes a consensus reconciling the diverse molecular classifications of muscle-invasive bladder cancer. This work offers a robust framework that will enable testing and validating predictive biomarkers in future prospective clinical trials.
PDF
