Cancer-Targeted BikDD Gene Therapy Elicits Protective Antitumor Immunity against Lung Cancer

Casein kinase II activates Bik to induce death of hyperplastic mucous cells in a cell cycle-dependent manner

Extensive inflammation causes epithelial cell hyperplasia in the airways and Bcl-2-interacting killer (Bik) reduces epithelial cell and mucous cell hyperplasia without affecting resting cells to restore homeostasis. These observations suggest that Bik induces apoptosis in a cell cycle-specific manner, but the mechanisms are not understood. Mice were exposed to an allergen for 3, 14, or 30 days and Bik expression was induced in airway epithelia of transgenic mice. Bik reduced epithelial and mucous cell hyperplasia when mice were exposed to an allergen for 3 or 14 days, but not when exposure lasted for 30 days, and Ki67-positivity was reduced. In culture, Bik expression killed proliferating cells but not quiescent cells. To capture the stage of the cell cycle when Bik induces cell death, airway cells that express fluorescent ubiquitin cell cycle indicators were generated that fluoresce red or green during the G0/G1 and S/G2/M phases of the cells cycle, respectively. Regardless of the cell cycle stage, Bik expression eliminated green-fluorescent cells. Also, Bik, when tagged with a blue-fluorescent protein, was only detected in green cells. Bik phosphorylation mutants at threonine 33 or serine 35 demonstrated that phosphorylation activated Bik to induce death even in quiescent cells. Immunoprecipitation and proteomic approaches identified casein kinase IIα to be responsible for phosphorylating and activating Bik to kill cells in S/G2/M. As casein kinase 2 alpha (CKIIα) is expressed only during the G2/M phase, we conclude that Bik activation in airway epithelial cells selectively targets hyperplastic epithelial cells, while leaving resting airway cells unaffected.

Identification of theranostic factors for patients developing metastasis after surgery for early-stage lung adenocarcinoma

Rationale: Lung adenocarcinoma (LUAD) is an aggressive disease with high propensity of metastasis. Among patients with early-stage disease, more than 30% of them may relapse or develop metastasis. There is an unmet medical need to stratify patients with early-stage LUAD according to their risk of relapse/metastasis to guide preventive or therapeutic approaches. In this study, we identified 4 genes that can serve both therapeutic and diagnostic (theranostic) purposes.

Methods: Three independent datasets (GEO, TCGA, and KMPlotter) were used to evaluate gene expression profile of patients with LUAD by unbiased screening approach. Upon significant genes uncovered, functional enrichment analysis was carried out. The predictive power of their expression on patient prognosis were evaluated. Once confirmed their theranostic roles by integrated bioinformatics, we further conducted in vitro and in vivo validation.

Results: We found that four genes (ADAM9, MTHFD2, RRM2, and SLC2A1) were associated with poor patient outcomes with an increased hazard ratio in LUAD. Knockdown of them, both separately and simultaneously, suppressed lung cancer cell proliferation and migration ability in vitro and prolonged survival time in metastatic tumor mouse models. Moreover, these four biomarkers were found to be overexpressed in tumor tissues from LUAD patients, and the total immunohistochemical staining scores correlated with poor prognosis.

Conclusions: These results suggest that these four identified genes could be theranostic biomarkers for stratifying high-risk patients who develop relapse/metastasis in early-stage LUAD. Developing therapeutic approaches for the four biomarkers may benefit early-stage LUAD patients after surgery.

The Utilization of Poly(2-ethyl-2-oxazoline)-b-Poly(ε-caprolactone) Ellipsoidal Particles for Intracellular BIKDDA Delivery to Prostate Cancer

Prostate cancer is the most common cancer, which is about 15-20% among male cancers worldwide. As most common strategies such as radiotherapy, chemotherapy, or surgery alone can be unsuccessful in the treatment of prostate cancer, this study aims to develop a new approach to deliver newly generated proapoptotic gene, BIKDDA, to androgen independent prostate cancer cells, 22RV1, using new generation nanocarriers called ellipsoids. As far as it is known, this is the first study that assesses the ability of proapoptotic gene BIKDDA to induce apoptosis in prostate cancer cell. BIKDDA encapsulating PEtOx-b-PCL-based ellipsoids are fabricated by solvent-switch method, and their morphology, size, and BIKDDA content are characterized. Gene delivery efficiency of BIKDDA loaded PEtOx-b-PCL ellipsoids is demonstrated by analysis of BIK mRNA expression with real-time PCR. The apoptotic effect of PEtOx-b-PCL ellipsoids loaded with BIKDDA (EPs-BIKDDA) on 22RV1 is shown by Annexin V staining. The obtained results demonstrate that the treatment of 22RV1 cells with EPs-BIKDDA can significantly increase BIK mRNA levels by 4.5-fold leading to cell death. This study not only represents BIKDDA as a potential therapeutic strategy in prostate cancer but also the capacity of ellipsoids as promising in vivo gene delivery vehicles.

BIK ubiquitination by the E3 ligase Cul5-ASB11 determines cell fate during cellular stress

The BH3-only pro-apoptotic protein BIK is regulated by the ubiquitin-proteasome system. However, the mechanism of this regulation and its physiological functions remain elusive. Here, we identify Cul5-ASB11 as the E3 ligase targeting BIK for ubiquitination and degradation. ER stress leads to the activation of ASB11 by XBP1s during the adaptive phase of the unfolded protein response, which stimulates BIK ubiquitination, interaction with p97/VCP, and proteolysis. This mechanism of BIK degradation contributes to ER stress adaptation by promoting cell survival. Conversely, genotoxic agents down-regulate this IRE1α-XBP1s-ASB11 axis and stabilize BIK, which contributes in part to the apoptotic response to DNA damage. We show that blockade of this BIK degradation pathway by an IRE1α inhibitor can stabilize a BIK active mutant and increase its anti-tumor activity. Our study reveals that different cellular stresses regulate BIK ubiquitination by ASB11 in opposing directions, which determines whether or not cells survive, and that blocking BIK degradation has the potential to be used as an anti-cancer strategy.

Gene Amplification-Driven Long Noncoding RNA SNHG17 Regulates Cell Proliferation and Migration in Human Non-Small-Cell Lung Cancer

Lung cancer is the most common cancer all around the world, with high morbidity and mortality. Long noncoding RNA (lncRNA) has been reported to have a critical role in non-small-cell lung cancer (NSCLC) proliferation and migration. In the present study, we analyzed The Cancer Genome Atlas (TCGA) data, and we found that lncRNA Small Nucleolar RNA Host Gene 17 (SNHG17) was upregulated in NSCLC driven by the amplification of copy number, indicating the special role of SNHG17 in NSCLC. The full exact length of SNHG17 was determined by rapid amplification of cDNA ends (RACE). We modulated SNHG17 expression by RNAi and a series of functional assays were performed. Flow cytometry was used to explore the involvement of SNHG17 in NSCLC cell apoptosis. Results showed that the knockdown of SNHG17 inhibited the proliferation and migration and promoted the apoptosis of NSCLC cells. We acquired the global gene expression profile regulated by SNHG17 in A549 through RNA sequencing (RNA-seq) assays. We found 637 genes were upregulated while 581 genes were downregulated. We selected three genes (FOXA1, XAF1, and BIK) that were closely related to proliferation and apoptosis, and we confirmed their altered expression in A549 and PC-9 cells treated with small interfering RNA si-SNHG17. Our findings indicated gene amplification-driven lncRNA SNHG17 promotes cell proliferation and migration in NSCLC, suggesting its potential value as a biomarker in NSCLC.

ADAM9 promotes lung cancer progression through vascular remodeling by VEGFA, ANGPT2, and PLAT

Lung cancer has a very high prevalence of brain metastasis, which results in a poor clinical outcome. Up-regulation of a disintegrin and metalloproteinase 9 (ADAM9) in lung cancer cells is correlated with metastasis to the brain. However, the molecular mechanism underlying this correlation remains to be elucidated. Since angiogenesis is an essential step for brain metastasis, microarray experiments were used to explore ADAM9-regulated genes that function in vascular remodeling. The results showed that the expression levels of vascular endothelial growth factor A (VEGFA), angiopoietin-2 (ANGPT2), and tissue plasminogen activator (PLAT) were suppressed in ADAM9-silenced cells, which in turn leads to decreases in angiogenesis, vascular remodeling, and tumor growth in vivo. Furthermore, simultaneous high expression of ADAM9 and VEGFA or of ADAM9 and ANGPT2 was correlated with poor prognosis in a clinical dataset. These findings suggest that ADAM9 promotes tumorigenesis through vascular remodeling, particularly by increasing the function of VEGFA, ANGPT2, and PLAT.

Kill and spread the word: stimulation of antitumor immune responses in the context of radiotherapy

Besides the direct, targeted effects of ionizing irradiation (x-ray) on cancer cells, namely DNA damage and cell death induction, indirect, nontargeted ones exist, which are mediated in large part by the immune system. Immunogenic forms of tumor cell death induced by x-ray, including immune modulating danger signals like the heat shock protein 70, adenosine triphosphate, and high-mobility group box 1 protein are presented. Further, antitumor effects exerted by cells of the innate (natural killer cells) as well as adaptive immune system (T cells activated by dendritic cells) are outlined. Tumor cell death inhibiting molecules such as survivin are introduced as suitable target for molecularly tailored therapies in combination with x-ray. Finally, reasonable combinations of immune therapies with radiotherapy are discussed.

Toll-like receptor 9 agonist enhances anti-tumor immunity and inhibits tumor-associated immunosuppressive cells numbers in a mouse cervical cancer model following recombinant lipoprotein therapy

Background

Although cytotoxic T lymphocytes (CTLs) play a major role in eradicating cancer cells during immunotherapy, the cancer-associated immunosuppressive microenvironment often limits the success of such therapies. Therefore, the simultaneous induction of cancer-specific CTLs and reversal of the immunosuppressive tumor microenvironment may be more effectively achieved through a single therapeutic vaccine. A recombinant lipoprotein with intrinsic Toll-like receptor 2 (TLR2) agonist activity containing a mutant form of E7 (E7m) and a bacterial lipid moiety (rlipo-E7m) has been demonstrated to induce robust CTL responses against small tumors. This treatment in combination with other TLR agonists is able to eliminate large tumors.

Methods

Mouse bone marrow-derived dendritic cells (DCs) were employed to determine the synergistic production of pro-inflammatory cytokines upon combination of rlipo-E7m and other TLR agonists. Antigen-specific CTL responses were investigated using immunospots or in vivo cytolytic assays after immunization in mice. Mice bearing various tumor sizes were used to evaluate the anti-tumor effects of the formulation. Specific subpopulations of immunosuppressive cells in the tumor infiltrate were quantitatively determined by flow cytometry.

Results

We demonstrate that a TLR9 agonist (unmethylated CpG oligodeoxynucleotide, CpG ODN) enhances CTL responses and eradicates large tumors when combined with rlipo-E7m. Moreover, combined treatment with rlipo-E7m and CpG ODN effectively increases tumor infiltration by CTLs and reduces the numbers of myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs) and regulatory T cells (Tregs) in the tumor microenvironment.

Conclusion

These findings suggest that the dramatic anti-tumor effects of the recombinant lipoprotein together with CpG ODN may reflect the amplification of CTL responses and the repression of the immunosuppressive environment. This promising approach could be applied for the development of additional therapeutic cancer vaccines.

BikDDA, a mutant of Bik with longer half-life expression protein, can be a novel therapeutic gene for triple-negative breast cancer

Our previous studies showed that BikDD, a constitutively active mutant form of Bik, exhibited powerful antitumor effects in preclinical pancreatic, lung and breast cancer models. Howerver, the antitumor activity of BikDD in triple-negative breast cancer (TNBC) is unknown. Here we show that aberrant expression of p-ERK1/2 was a meaningful molecular phenotype in TNBC patients, and can be an obstacle for treatment because of the converse correlation with Bik. A novel mutant, BikDDA, in which Ser¹²⁴ was changed to Alanine to block BikDD phosphorylation by p-ERK1/2 prevented subsequent ubiquitin-proteasome degradation. BikDDA showed a prolonged half-life and enhanced pro-apoptotic ability in TNBC cells compared with BikDD. Moreover, aberrant expression of p-ERK1/2 was associated with 5-fluorouracil resistance in breast cancer patients and BikDDA enhanced the therapeutic effects of 5-fluorouracil in vitro.

Optimization and preclinical design of genetically engineered viruses for human oncolytic therapy

INTRODUCTION

Oncolytic viruses (OVs) occupy a strategic niche in the dynamic era of biological and gene therapy of human cancers. However, the use of OVs is the subject of close scrutiny due to impediments such as the insufficiency of patient generalizations posed by heterogeneous tumor responses to treatment, inherent or potentially lethal viral pathogenicities, unanticipated host- or immune-related adverse effects, and the emergence of virus-resistant cancer cells. These challenges can be overcome by the design and development of more definitive (optimized, targeted, and individualized) cancer virotherapeutics.

AREAS COVERED

The translation of current knowledge and recent innovations into rational treatment prospects hinges on an iterative loop of variables pertaining to genetically engineered viral oncolytic efficacy and safety profiles, mechanism-of-action data, potencies of synergistic oncolytic viral combinations with conventional tumor, immuno-, chemo-, and radiation treatment modalities, optimization of the probabilities of treatment successes in heterogeneous (virus-sensitive and -resistant) tumor cell populations by mathematical modeling, and lessons learned from preclinical studies and human clinical trials.

EXPERT OPINION

In recent years, it has become increasingly clear that proof-of-principle is critical for the preclinical optimization of oncolytic viruses to target heterogeneous forms of cancer and to prioritize current concerns related to the efficacy and safety of oncolytic virotherapy.