Paraffin-embedded Human Samples Research Articles

Targeting Neuropilin‐2 in Lymphatic Malformation

Lymphatic malformations (LM) are sporadic, non‐familial congenital lesions consisting of dilated, abnormal lymphatic vessels that can cause severe lymphedema, disfigurement, organ dysfunction, and in some cases morbidity. These vascular anomalies grow slowly but progress over time and recur after surgery; no effective drugs or preventions currently exist for LM. Genome sequencing identified that approximately 80% of LM patients have somatic activating mutations in the PIK3CA gene. Lymphatic endothelial cells (LEC) expressing mutant PIK3CAH1047Rinduce both macrocystic and microcystic LM in mouse models. Our goal is to understand the cellular and molecular processes that regulate LM growth in order to develop novel therapeutic strategies for patients with LM. Neuropilin‐2 (NRP2) is an essential co‐receptor for VEGFC/VEGFR3 signaling through the PI3K/AKT pathway which is crucial for LEC viability and motility, yet NRP2 also mediates inhibitory signals from its Semaphorin‐3F (SEMA3F) ligand to attenuate activation of AKT and induce cytostasis. Our results using immunohistochemistry to detect NRP2 protein in paraffin‐embedded human samples indicate that NRP2 is highly upregulated in LM lesions compared to normal lymphatic vessels. LM‐LEC primary cell lines, derived separately from several patients, show increased NRP2 levels and hyper‐activated AKT compared to primary LEC derived from healthy human dermis. Additionally, LEC isolated from the skin of transgenic mice (prox1‐creERT2;Nrp2 f/f) specifically lacking Nrp2 in lymphatic vessels following tamoxifen induction (LEC‐Nrp2‐KO) show suppressed proliferation and migration following VEGF‐C stimulation compared to normal LEC isolated from wildtype mice. Importantly, SEMA3F exogenous protein, in a dose‐dependent manner, inhibits the proliferation of normal LEC and LM‐LEC and attenuates the phosphorylation of AKT. Taken together, our study suggests that NRP2 may be an important target for therapy in LM patients. Future studies using SEMA3F protein or specific antibodies targeting the VEGF‐binding domain of NRP2 will be tested in preclinical trials.

Radiosensitivity-Specific Proteomic and Signaling Pathway Network of Non-Small Cell Lung Cancer (NSCLC)

An unmet clinical need in non-small cell lung cancer (NSCLC) management is the accurate prediction of radiation response in patients receiving radical radiation therapy. We explored the intrinsic radiosensitivity of NSCLC from the proteomic profiles of NSCLC cell lines and paraffin-embedded human samples. To uncover radiosensitivity-specific proteomic and signaling pathways, we performed quantitative proteomics by data-independent acquisition mass spectrometry assay on 29 human NSCLC cell lines and 13 paraffin-embedded human NSCLC samples. We validated closely interacting radioresistant proteins by western blotting, immunofluorescence, real-time quantitative polymerase chain reaction in NSCLC cell lines, and immunohistochemistry in paraffin-embedded human samples. We validated the functions of 3 key hub proteins by lentivirus transfection, clonogenic survival assay, and flow cytometry. The proteomic profiling of NSCLC showed that the intrinsic radiosensitivity of NSCLC is mainly modulated by signaling pathways of proteoglycans in cancer, focal adhesion, and regulation of the actin cytoskeleton. We identified 71 differentially expressed proteins and validated 8 closely interacting proteins as radioresistant proteins of NSCLC. Moreover, we also validated the functionality of integrin-linked protein kinase, p21-activated kinase 1, and Ras GTPase-activating-like protein IQGAP1 in the radiation response of NSCLC cell lines. Finally, with the NSCLC radiosensitivity-specific proteins, we delineated the atlas network of NSCLC radiosensitivity-related signaling pathways. Radiosensitivity-specific proteins could guide individualized radiation therapy in clinical practice by predicting the radiation response of patients with NSCLC. Moreover, the NSCLC radiosensitivity-related signaling pathway atlas could guide further exploration of the underlying mechanism.

RNA-guided diagnostics and therapeutics for next-generation individualized nanomedicine

The absence of reliable quantitative laboratory tests for measurements of microRNAs and other classes of small noncoding RNAs in archived, formalin- fixed, paraffin-embedded human samples with sufficient specificity and sensitivity has significantly limited the development of clinically relevant noncoding RNA–based diagnostic and therapeutic applications. A report by Renwick et al. in this issue of the JCI presents a significant technical and methodological advance toward the development of reliable clinical laboratory- compatible multicolor RNA FISH methodology for molecular diagnostic applications and the near-term prospect of introduction of microRNA- based biomarkers into clinical practice. Further, this work is likely to advance the development of RNA-based therapeutics and next-generation individualized nanomedicine.

Roles for USF‐2 in lung cancer proliferation and bronchial carcinogenesis

The upstream stimulatory factors USF-1 and USF-2 dimerize to regulate transcription through E-box motifs in target genes. Although widely expressed, they can mediate tissue-specific transcription and we previously reported that USF-2 can enhance transcription of arginine vasopressin, a neuropeptide growth factor in small cell lung cancer. Here we determine the expression and role of USF-2 in lung cancer subtypes and examine USF-2 distribution in the bronchial epithelium. For a panel of 12 cell lines and 10 frozen human tumour samples, immunoblotting demonstrated that USF-2 expression was more frequent and abundant in small cell lung cancer than in non-small cell lung cancer. An immunohistochemical study of 108 formalin-fixed and paraffin-embedded human samples was undertaken to localize USF-2 expression and included 44 small cell and 32 non-small cell lung cancers, and 32 samples with bronchial dysplasia. USF-2 was restricted to ciliated cells in normal bronchial epithelium, but was more strongly expressed in dysplastic epithelium (72%) and certain lung cancer types, including small cell lung cancer (71%), squamous cell carcinoma (69%) and a large cell neuroendocrine carcinoma, but was less common in adenocarcinoma (11%). In a small series, expression was assessed adjacent to positively staining tumours; in phenotypically normal bronchial tissues, USF-2 was more highly expressed at 1 cm than at 5 cm from the tumour. Transient USF-2 overexpression in non-small cell lung cancer cell lines significantly stimulated in vitro cell proliferation; this response was most apparent for NCI-H460 (p < 0.005), reducing the mean cell doubling time from 19 to 16 h. Dominant-negative USF-2 mutants had no significant effect on cell growth. Taken together, these data suggest that USF-2 represents a relatively early molecular marker for the development of bronchial dysplasia and non-adenocarcinoma lung cancer. USF may also play a role in bronchial carcinogenesis, perhaps through promoting cell proliferation, although the genes through which this is regulated remain to be determined.