IL-12 gene-modified bone marrow cell therapy suppresses the development of experimental metastatic prostate cancer

Bone Health Management in the Continuum of Prostate Cancer Disease

Prostate cancer (PCa) is the second-leading cause of cancer-related deaths in men. PCa cells require androgen receptor (AR) signaling for their growth and survival. Androgen deprivation therapy (ADT) is the preferred treatment for patients with locally advanced and metastatic PCa disease. Despite their initial response to androgen blockade, most patients eventually will develop metastatic castration-resistant prostate cancer (mCRPC). Bone metastases are common in men with mCRPC, occurring in 30% of patients within 2 years of castration resistance and in >90% of patients over the course of the disease. Patients with mCRPC-induced bone metastasis develop lesions throughout their skeleton; the 5-year survival rate for these patients is 47%. Bone-metastasis-induced early changes in the bone that proceed the osteoblastic response in the bone matrix are monitored and detected via modern magnetic resonance and PET/CT imaging technologies. Various treatment options, such as targeting osteolytic metastasis with bisphosphonates, prednisone, dexamethasone, denosumab, immunotherapy, external beam radiation therapy, radiopharmaceuticals, surgery, and pain medications are employed to treat prostate-cancer-induced bone metastasis and manage bone health. However, these diagnostics and treatment options are not very accurate nor efficient enough to treat bone metastases and manage bone health. In this review, we present the pathogenesis of PCa-induced bone metastasis, its deleterious impacts on vital organs, the impact of metastatic PCa on bone health, treatment interventions for bone metastasis and management of bone- and skeletal-related events, and possible current and future therapeutic options for bone management in the continuum of prostate cancer disease.

Timp3 loss accelerates tumour invasion and increases prostate inflammation in a mouse model of prostate cancer

BACKGROUND

Altered expression and activity of proteases is implicated in inflammation and cancer progression. An important negative regulator of protease activity is TIMP3 (tissue inhibitor of metalloproteinase 3). TIMP3 expression is lacking in many cancers including advanced prostate cancer, and this may facilitate invasion and metastasis by allowing unrestrained protease activity.

METHODS

To investigate the role of TIMP3 in prostate cancer progression, we crossed TIMP3-deficient mice (Timp3(-/-)) to mice with prostate-specific deletion of the tumor suppressor Pten (Pten(-/-)), a well-established mouse model of prostate cancer. Tumor growth and progression were compared between Pten(-/-), Timp3(-/-) and control (Pten(-/-), Timp3(+/+)) mice at 16 weeks of age by histopathology and markers of proliferation, vascularity, and tumor invasion. Metalloproteinase activity within the tumors was assessed by gelatin zymography. Inflammatory infiltrates were assessed by immunohistochemistry for macrophages and lymphocytes whereas expression of cytokines and other inflammatory mediators was assessed by quantitative real time PCR and multiplex ELISA.

RESULTS

Increased tumor growth, proliferation index, increased microvascular density, and invasion was observed in Pten(-/-), Timp3(-/-) prostate tumors compared to Pten(-/-), Timp3(+/+) tumors. Tumor cell invasion in Pten(-/-), Timp3(-/-) mice was associated with increased expression of matrix metalloprotease (MMP)-9 and activation of MMP-2. There was markedly increased inflammatory cell infiltration into the TIMP3-deficient prostate tumors along with increased expression of monocyte chemoattractant protein-1, cyclooxygenase-2, TNF-α, and interleukin-1β; all of which are implicated in inflammation and cancer.

CONCLUSIONS

This study provides important insights into the role of altered protease activity in promoting prostate cancer invasion and implicates prostate inflammation as an important promoting factor in prostate cancer progression.

Efficacy of oncolytic adenovirus expressing suicide genes and interleukin-12 in preclinical model of prostate cancer

Oncolytic adenovirus-mediated suicide gene therapy has been shown to improve local tumor control in preclinical tumor models and in the clinic. Although local tumor control is important, for most human cancers, new therapies must also target metastatic disease if they are to have an impact on survival. Here, we test the hypothesis that adding cytokine gene therapy to our multimodal platform improves both local and metastatic tumor control in a preclinical model of prostate cancer. An oncolytic adenovirus (Ad5-yCD/mutTKSR39rep-mIL12) expressing two suicide genes and mouse interleukin-12 (IL-12) was generated. Relative to an adenovirus lacking IL-12 (Ad5-yCD/mutTKSR39rep), Ad5-yCD/mutTKSR39rep-mIL12 improved local and metastatic tumor control in the TRAMP-C2 prostate adenocarcinoma model, resulting in a significant increase in survival. Ad5-yCD/mutTKSR39rep-mIL12 resulted in high levels of IL-12 and interferon gamma in serum and tumor, increased natural killer (NK) and cytotoxic T-lymphocyte lytic activities, and the development of tumor-specific antitumor immunity. Immune cell depletion studies indicated that both the innate and adaptive arms of immunity were required for maximal Ad5-yCD/mutTKSR39rep-mIL12 activity. The results demonstrate that the addition of IL-12 significantly improves the efficacy of oncolytic adenovirus-mediated suicide gene therapy and provide the scientific basis for future trials targeting locally aggressive cancers.

Strategies for the discovery and development of therapies for metastatic breast cancer

Nearly all deaths caused by solid cancers occur as a result of metastasis--the formation of secondary tumours in distant organs such as the lungs, liver, brain and bone. A major obstruction to the development of drugs with anti-metastatic efficacy is our fragmented understanding of how tumours 'evolve' and metastasize, at both the biological and genetic levels. Furthermore, although there is significant overlap in the metastatic process among different types of cancer, there are also marked differences in the propensity to metastasize, the extent of metastasis, the sites to which the tumour metastasizes, the kinetics of the process and the mechanisms involved. Here, we consider the case of breast cancer, which has some marked distinguishing features compared with other types of cancer. Considerable progress has been made in the development of preclinical models and in the identification of relevant signalling pathways and genetic regulators of metastatic breast cancer, and we discuss how these might facilitate the development of novel targeted anti-metastatic drugs.

Recent developments in prostate cancer biomarker research: therapeutic implications

This review aims to present an overview of recent clinical trials targeting biomarkers in advanced prostate cancer. We searched ClinicalTrials.gov for early phase clinical trials on treatments of prostate cancer that have been recently completed, are ongoing or are actively recruiting participants. Drug targets and their mechanism of actions were assessed and summarized. Trials were categorized according to prostate cancer biomarkers that have potential as therapeutic targets. A total of 19 new therapeutic agents for the treatment of prostate cancer are included in this review. Trials are summarized according to the targeted biomarkers and are categorized into five therapeutic approaches: prostate cancer vaccine, epigenetic therapy, pro-apoptotic agents, prostate cancer antibodies and anti-angiogenesis approach. Some of the therapeutic agents reviewed showed promising results, warranting further investigation in late phase clinical trials. Recent novel prostate cancer biomarkers that made it through clinical trials and their relevance as drug targets are summarized. This review emphasizes the importance of specific prostate cancer biomarkers and their potentials as targets of the disease. Some clinical trials of targeted treatments in prostate cancer show promising results. Better understanding of disease mechanisms should potentially lead to more specific treatments for individual patients.

Additive antitumoral effect of interleukin-12 gene therapy and chemotherapy in the treatment of urothelial bladder cancer in vitro and in vivo

BACKGROUND

We evaluated antitumoral effect of combined chemotherapy and interleukin-12 (IL-12) gene therapy in in vitro and in vivo experimental urothelial bladder cancer (UBC) model.

MATERIALS AND METHODS

EJ UBC cells were transfected with recombinant IL-12 genes using a liposomal transfection agent. Pirarubicin (THP) was added to the experimental samples at a final concentration of 20 mg/l. Four groups were assigned in vitro: untreated cells, transfected cells, untransfected cells plus THP and transfected cells plus THP. Death rates (DR) and cellular micromorphologic changes were evaluated. Bladder tumor model was established by subcutaneous injection of EJ cells to the nude mice. Four groups were assigned in vivo: control group; THP group; IL-12 gene group and IL-12 gene plus THP group. After injection of combined THP and IL-12 gene therapy, tumor size and IL-12 levels were evaluated.

RESULTS

In vitro study: DR in the THP + IL-12 gene therapy group (58.2 ± 15.8%) was significantly higher than transfected group (12.2 ± 5.6%; P = 0.01) and untransfected cells plus THP group (33.4 ± 7.8; P = 0.046). A higher amount of apoptotic changes and necrosis on transmission electron microscope analysis were observed in transfected cells plus THP group. In vivo study: A significant tumor attenuation was found in IL-12 gene in combination with THP group when compared with any other groups that were treated without Il-12 or THP (P < 0.05). IL-12 levels in serum were significant high in IL-12 gene groups (P < 0.01).

CONCLUSION

The combination of THP chemotherapy and IL-12 gene therapy showed an additive antitumoral effect on bladder cancer cells in vitro and in vivo. Further investigation should be focused on high-level transgene protocols in vivo.

Non-Steroidal Anti-Inflammatory Drugs, Variation in Inflammatory Genes, and Aggressive Prostate Cancer

Increasing evidence suggests that prostatic inflammation plays a key role in the development of prostate cancer. It remains controversial whether non-steroidal anti-inflammatory drugs (NSAIDs) reduce the risk of prostate cancer. Here, we investigate how a previously reported inverse association between NSAID use and the risk of aggressive prostate cancer is modulated by variants in several inflammatory genes. We found that NSAIDs may have differential effects on prostate cancer development, depending on one’s genetic makeup. Further study of these inflammatory pathways may clarify the mechanisms through which NSAIDs impact prostate cancer risk.

Advances in viral-vector systemic cytokine gene therapy against cancer

Current strategies for cancer gene therapy consist mainly of direct inhibition of tumor cell growth and activation of systemic host defense mechanisms. Cytokine gene-transduced tumor cells have been used as vaccines in clinical trials, which have shown good safety profiles and some local responses but substantial lack of systemic efficacy. Cytokines should be directed at the level of gene selection and delivery, in order to identify the optimal cytokine and achieve efficient and durable cytokine expression at the level of improving immune stimulation. In this review, we will summarize the current achievements of cytokine gene therapy, especially viral-vector, and their applications in cancer treatment. Additionally, we will also discuss and propose future perspectives about cancer gene therapy.

Gene-modified bone marrow cell therapy for prostate cancer

There is a critical need to develop new and effective cancer therapies that target bone, the primary metastatic site for prostate cancer and other malignancies. Among the various therapeutic approaches being considered for this application, gene-modified cell-based therapies may have specific advantages. Gene-modified cell therapy uses gene transfer and cell-based technologies in a complementary fashion to chaperone appropriate gene expression cassettes to active sites of tumor growth. In this paper, we briefly review potential cell vehicles for this approach and discuss relevant gene therapy strategies for prostate cancer. We further discuss selected studies that led to the conceptual development and preclinical testing of IL-12 gene-modified bone marrow cell therapy for prostate cancer. Finally, we discuss future directions in the development of gene-modified cell therapy for metastatic prostate cancer, including the need to identify and test novel therapeutic genes such as GLIPR1.