A Novel Controlled PTEN-Knockout Mouse Model for Prostate Cancer Study

A replicative recombinant HPV16 E7 expression virus upregulates CD36 in C33A cells

Objective

In past decades, the role of high-risk HPV (HR-HPV) infection in cancer pathogenesis has been extensively studied. The viral E7 protein expressed in pre-malignant cells has been identified as an ideal target for immunological intervention. However, the cultivation of HPV in vitro remains a significant challenge, as well as the lack of methods for expressing the HPV E7 protein and generating replication-competent recombinant viral particles, which posed a major obstacle to further exploration of the function and carcinogenic mechanisms of the E7 oncoprotein. Therefore, it is imperative to investigate novel methodologies to construct replication-competent recombinant viral particles that express the HPV E7 protein to facilitate the study of its function.

Methods

We initiated the construction of recombinant viral particles by utilizing the ccdB-Kan forward/reverse screening system in conjunction with the Red/ExoCET recombinant system. We followed the infection of C33A cells with the obtained recombinant virus to enable the continuous expression of HPV16 E7. Afterwards, the total RNA was extracted and performed transcriptome sequencing using RNA-Seq technology to identify differentially expressed genes associated with HPV-induced oncogenicity.

Results

We successfully established replicative recombinant viral particles expressing HPV16 E7 stably and continuously. The C33A cells were infected with recombinant viral particles to achieve overexpression of the E7 protein. Subsequently, RNA-Seq analysis was conducted to assess the changes in host cell gene expression. The results revealed an upregulation of the CD36 gene, which is associated with the HPV-induced oncogenic pathways, including PI3K-Akt and p53 signaling pathway. qRT-PCR analysis further identified that the upregulation of the CD36 gene due to the expression of HPV16 E7.

Conclusion

The successful expression of HPV16 E7 in cells demonstrates that the replicated recombinant virus retains the replication and infection abilities of Ad4, while also upregulating the CD36 gene involved in the PI3K-Akt signaling and p53 pathways, thereby promoting cell proliferation. The outcome of this study provides a novel perspective and serves as a solid foundation for further exploration of HPV-related carcinogenesis and the development of replicative HPV recombinant vaccines capable of inducing protective immunity against HPV.

Addressing the Reciprocal Crosstalk between the AR and the PI3K/AKT/mTOR Signaling Pathways for Prostate Cancer Treatment

The reduction in androgen synthesis and the blockade of the androgen receptor (AR) function by chemical castration and AR signaling inhibitors represent the main treatment lines for the initial stages of prostate cancer. Unfortunately, resistance mechanisms ultimately develop due to alterations in the AR pathway, such as gene amplification or mutations, and also the emergence of alternative pathways that render the tumor less or, more rarely, completely independent of androgen activation. An essential oncogenic axis activated in prostate cancer is the phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway, as evidenced by the frequent alterations of the negative regulator phosphatase and tensin homolog (PTEN) and by the activating mutations in PI3K subunits. Additionally, crosstalk and reciprocal feedback loops between androgen signaling and the PI3K/AKT/mTOR signaling cascade that activate pro-survival signals and play an essential role in disease recurrence and progression have been evidenced. Inhibitors addressing different players of the PI3K/AKT/mTOR pathway have been evaluated in the clinic. Only a limited benefit has been reported in prostate cancer up to now due to the associated side effects, so novel combination approaches and biomarkers predictive of patient response are urgently needed. Here, we reviewed recent data on the crosstalk between AR signaling and the PI3K/AKT/mTOR pathway, the selective inhibitors identified, and the most advanced clinical studies, with a focus on combination treatments. A deeper understanding of the complex molecular mechanisms involved in disease progression and treatment resistance is essential to further guide therapeutic approaches with improved outcomes.

Erlotinib-Modified BODIPY Photosensitizers for Targeted Photodynamic Therapy

Photodynamic therapy (PDT) is an innovative, non-invasive and highly selective therapeutic modality for tumours and non-malignant diseases. BODIPY based molecules can function as new generation photosensitizers (PSs) in various PDT applications. Despite numerous conjugated PS systems are available, BODIPYs containing erlotinib lagged behind other photosensitizer units. In this study, smart photosensitizers containing BODIPY, erlotinib and hydrophilic units were prepared for the first time, their physicochemical properties and PDT effects were investigated. Compared with non-halogenated compound, halogenated derivatives possessed much lower fluorescence profile as well as the good ROS generation ability under red light. In vitro PDT studies were performed on both healthy (PNT1a) and prostate cancerous cells (PC3) to determine the selectivity of the compounds on cancerous cells and their effects under light. The halogenated conjugates, exposed to low dose of light illumination exhibited potent activity on cancer cell viability and the calculated IC₅₀ values proved the high phototoxicity of the photosensitizers. It was also determined that the PSs have very low dark toxicity and that the light illumination and ROS formation are required for the initiation of the cell death mechanism. As a result, erlotinib modified BODIPYs could serve as promising agents in anticancer photodynamic therapy.

A Novel Strategy to Model Age-Related Cancer for Elucidation of the Role of Th17 Inflammaging in Cancer Progression

Cancer is a disease of aging, but most studies on cancer are in young but not aged animal models, and cancer clinical trials are rarely performed in older adults. Recognition of the connections between aging and cancer and improvement of treatment for elderly cancer patients has become one of the most critical medical issues with the global increase in the elderly population. Mouse models are essential experimental tools for understanding the molecular mechanisms of complex processes and related gene pathways of biological aging. However, few mouse models can be used to understand the role of aging in cancer development and the underlying mechanisms. One of the hallmarks of aging is chronic inflammation, often called inflammaging. This is our rationale for examining the role of aging-related inflammation in prostate cancer, a major aging malignancy. We have now developed a novel method to generate age-related cancer models in mice to better understand how age impacts cancer initiation and progression in the natural aging process. We discuss its application to elucidate some of the contributing mechanisms.

Preclinical and Clinical Research Models of Prostate Cancer: A Brief Overview

The incidence and mortality from prostate cancer (PCa) are on the rise which poses a major public health concern worldwide. In this narrative review, we have summarized the characteristics of major in vitro and in vivo PCa models including their utility in developing treatment strategies. Androgens, particularly, testosterone and dihydrotestosterone (DHT) activate the androgen receptor (AR) signaling pathway that facilitates the development and progression of castration resistant PCa. Several enzymes namely, CYP17A1, HSD17B, and SRD5A are essential to furnishing DHT from dehydroepiandrosterone in the classical pathway while DHT is formed from androstanediol in the backdoor pathway. The advancement in delineating the molecular heterogeneity of PCa has been possible through the development of several in vitro and in vivo research models. Generally, tissue culture models are advantageous to understand PCa biology and investigate the efficacy and toxicity of novel agents; nevertheless, animal models are indispensable to studying the PCa etiology and treatment since they can simulate the tumor microenvironment that plays a central role in initiation and progression of the disease. Moreover, the availability of several genetically engineered mouse models has made it possible to study the metastasis process. However, the conventional models are not devoid of limitations. For example, the lack of heterogeneity in tissue culture models and the variation of metastatic characteristics in xenograft models are obviously challenging. Additionally, due to the racial and ethnic disparities in PCa pathophysiology, a new model that can represent PCa encompassing different ethnicities is urgently needed. New models should continue to evolve to address the genetic and molecular complexities as well as to further elucidate the finer details of the steroidogenic pathway associated with PCa.