Combined oncolytic adenovirus carrying MnSOD and mK5 genes both regulated by survivin promoter has a synergistic inhibitory effect on gastric cancer.

Gastric cancer (GC) is one of the major causes of cancer-related mortality. The use of oncolytic virus for cancer gene-virotherapy is a new approach for the treatment of human cancers. In this study, a novel Survivin promoter-driven recombinant oncolytic adenovirus carrying mK5 or MnSOD gene was constructed, which was modified after deletion of the E1B gene. Human plasminogen Kringle 5 mutant (mK5) and manganese superoxide dismutase (MnSOD) are both potential tumor suppressor genes. By constructing Ad-Surp-mK5 and Ad-Surp-MnSOD oncolytic adenoviruses, we hypothesized that the combination of the two viruses would enhance the therapeutic efficacy of GC as compared to the one virus alone. The results of the in vitro experiments revealed that the combination of adenovirus carrying mK5 and MnSOD gene exhibited stronger cytotoxicity to GC cell lines as compared to the virus alone. Additionally, the virus could selectively kill cancer cells and human somatic cells. Cell staining, flow cytometry, and western blot analysis showed that the combination of two adenoviruses containing therapeutic genes could promote the apoptosis of cancer cells. In vivo experiments further verified that Ad-Surp-mK5 in combination with Ad-Surp-MnSOD exhibited a significant inhibitory effect on the growth of GC tumor xenograft as compared to the virus alone, and no significant difference was observed in the bodyweight of treatment and the normal mice. In conclusion, the combination of our two newly constructed recombinant oncolytic adenoviruses containing mK5 or MnSOD therapeutic genes could significantly inhibit gastric cancer growth by inducing apoptosis, suggestive of its potential for GC therapy.

Enhanced anti-melanoma efficacy through a combination of the armed oncolytic adenovirus ZD55-IL-24 and immune checkpoint blockade in B16-bearing immunocompetent mouse model.

Although the recent treatment in melanoma through the use of anti-PD-1 immunotherapy is successful, the efficacy of this approach remains to be improved. Here, we explore the feasibility of combination strategy with the armed oncolytic adenovirus ZD55-IL-24 and PD-1 blockade. We find that combination therapy with localized ZD55-IL-24 and systemic PD-1 blockade leads to synergistic inhibition of both local and distant established tumors in B16-bearing immunocompetent mouse model. Our further mechanism investigation reveals that synergistic therapeutic effect is associated with marked promotion of tumor immune infiltration and recognition in both local and distant tumors as well as spleens. PD-1 blockade has no obvious effect on promotion of tumor immune infiltration and recognition. Localized therapy with ZD55-IL-24, however, can help PD-1 blockade to overcome the limitation of relatively low tumor immune infiltration and recognition. This study provides a rationale for investigation of such combination therapy in the clinic.

Trail armed oncolytic poxvirus suppresses lung cancer cell by inducing apoptosis.

Lung cancer has a high morbidity rate worldwide and is often resistant to therapy. Oncolytic virus therapy is a developing trend for cancer treatment. Thus, we constructed an oncolytic poxvirus carrying human trail gene that expresses a membrane-binding tumor necrosis factor and associated apoptosis-inducing ligand (TRAIL, Oncopox-trail). We hypothesized that the expression of trail would increase the efficacy of the oncolytic poxvirus. The effect of the TRAIL protein depends on the death receptors on the surface of different cancer cells. The expression of death receptors in lung cancer cell lines was analyzed by western blot analysis. In vitro, the oncolytic poxvirus carrying the trail gene displayed a better cytotoxicity at the cell level in the lung cancer cell line than that carrying the Oncopox-empty. TRAIL protein mainly induced apoptosis and inhibited necrosis. In vivo, two transplanted tumor models of human A549 lung cancer cells and mouse Lewis lung cancer cells were used to verify the anti-cancer effect of the oncolytic poxvirus carrying the trail gene. TUNEL staining results of the tumor histological sections also verified the anti-cancer effect. Similarly, through systemic administration of Oncopox-trail, the oncolytic poxvirus also exhibited anti-cancer effect.

Overview of role of survivin in cancer: expression, regulation, functions, and its potential as a therapeutic target.

Survivin holds significant importance as a member of the inhibitor of apoptosis protein (IAP) family due to its predominant expression in tumours rather than normal terminally differentiated adult tissues. The high expression level of survivin in tumours is closely linked to chemotherapy resistance, heightened tumour recurrence, and increased tumour aggressiveness and serves as a negative prognostic factor for cancer patients. Consequently, survivin has emerged as a promising therapeutic target for cancer treatment. In this review, we delve into the various biological characteristics of survivin in cancers and its pivotal role in maintaining immune system homeostasis. Additionally, we explore different therapeutic strategies aimed at targeting survivin.

Double-modified oncolytic adenovirus armed with a recombinant interferon-like gene enhanced abscopal effects against malignant glioma.

Background: The development of new therapies for malignant gliomas has been stagnant for decades. Through the promising outcomes in clinical trials of oncolytic virotherapy, there is now a glimmer of hope in addressing this situation. To further enhance the antitumor immune response of oncolytic viruses, we have equipped a modified oncolytic adenovirus (oAds) with a recombinant interferon-like gene (YSCH-01) and conducted a comprehensive evaluation of the safety and efficacy of this modification compared to existing treatments. Methods: To assess the safety of YSCH-01, we administered the oAds intracranially to Syrian hamsters, which are susceptible to adenovirus. The efficacy of YSCH-01 in targeting glioma was evaluated through in vitro and in vivo experiments utilizing various human glioma cell lines. Furthermore, we employed a patient-derived xenograft model of recurrent glioblastoma to test the effectiveness of YSCH-01 against temozolomide. Results: By modifying the E1A and adding survivin promoter, the oAds have demonstrated remarkable safety and an impressive ability to selectively target tumor cells. In animal models, YSCH-01 exhibited potent therapeutic efficacy, particularly in terms of its distant effects. Additionally, YSCH-01 remains effective in inhibiting the recurrent GBM patient-derived xenograft model. Conclusions: Our initial findings confirm that a double-modified oncolytic adenovirus armed with a recombinant interferon-like gene is both safe and effective in the treatment of malignant glioma. Furthermore, when utilized in combination with a targeted therapy gene strategy, these oAds exhibit a more profound effect in tumor therapy and an enhanced ability to inhibit tumor growth at remote sites.

HCCS1-armed, quadruple-regulated oncolytic adenovirus specific for liver cancer as a cancer targeting gene-viro-therapy strategy.

BACKGROUND: In previously published studies, oncolytic adenovirus-mediated gene therapy has produced good results in targeting cancer cells. However, safety and efficacy, the two most important aspects in cancer therapy, remain serious challenges. The specific expression or deletion of replication related genes in an adenovirus has been frequently utilized to regulate the cancer cell specificity of a virus. Accordingly, in this study, we deleted 24 bp in E1A (bp924-bp947) and the entirety of E1B, including those genes encoding E1B 55kDa and E1B19kDa. We used the survivin promoter (SP) to control E1A in order to construct a new adenovirus vector named Ad.SP.E1A(Δ24).ΔE1B (briefly Ad.SPDD). HCCS1 (hepatocellular carcinoma suppressor 1) is a novel tumor suppressor gene that is able to specifically induce apoptosis in cancer cells. The expression cassette AFP-HCCS1-WPRE-SV40 was inserted into Ad.SPDD to form Ad.SPDD-HCCS1, enabling us to improve the safety and efficacy of oncolytic-mediated gene therapy for liver cancer. RESULTS: Ad.SPDD showed a decreased viral yield and less toxicity in normal cells but enhanced toxicity in liver cancer cells, compared with the cancer-specific adenovirus ZD55 (E1B55K deletion). Ad.SPDD-HCCS1 exhibited a potent anti-liver-cancer ability and decreased toxicity in vitro. Ad.SPDD-HCCS1 also showed a measurable capacity to inhibit Huh-7 xenograft tumor growth on nude mice. The underlying mechanism of Ad.SPDD-HCCS1-induced liver cancer cell death was found to be via the mitochondrial apoptosis pathway. CONCLUSIONS: These results demonstrate that Ad.SPDD-HCCS1 was able to elicit reduced toxicity and enhanced efficacy both in vitro and in vivo compared to a previously constructed oncolytic adenovirus. Ad.SPDD-HCCS1 could be a promising candidate for liver cancer therapy.

The folate cycle enzyme MTHFD2 induces cancer immune evasion through PD-L1 up-regulation.

Metabolic enzymes and metabolites display non-metabolic functions in immune cell signalling that modulate immune attack ability. However, whether and how a tumour's metabolic remodelling contributes to its immune resistance remain to be clarified. Here we perform a functional screen of metabolic genes that rescue tumour cells from effector T cell cytotoxicity, and identify the embryo- and tumour-specific folate cycle enzyme methylenetetrahydrofolate dehydrogenase 2 (MTHFD2). Mechanistically, MTHFD2 promotes basal and IFN-γ-stimulated PD-L1 expression, which is necessary for tumourigenesis in vivo. Moreover, IFN-γ stimulates MTHFD2 through the AKT-mTORC1 pathway. Meanwhile, MTHFD2 drives the folate cycle to sustain sufficient uridine-related metabolites including UDP-GlcNAc, which promotes the global O-GlcNAcylation of proteins including cMYC, resulting in increased cMYC stability and PD-L1 transcription. Consistently, the O-GlcNAcylation level positively correlates with MTHFD2 and PD-L1 in pancreatic cancer patients. These findings uncover a non-metabolic role for MTHFD2 in cell signalling and cancer biology.

Optimization of the Administration Strategy for the Armed Oncolytic Adenovirus ZD55-IL-24 in Both Immunocompromised and Immunocompetent Mouse Models.

ZD55-IL-24 is an armed oncolytic adenovirus similar but superior to ONYX-015. Virotherapeutic strategies using ZD55-IL-24 have been demonstrated to be effective against several cancer types. However, it is unclear whether the traditional administration strategy is able to exert the maximal antitumor efficacy of ZD55-IL-24. In this study, we sought to optimize the administration strategy of ZD55-IL-24 in both A375-bearing immunocompromised mouse model and B16-bearing immunocompetent mouse model. Although the underlying antitumor mechanisms are quite different, the obtained results are similar in these two mouse tumor models. We find that the antitumor efficacy of ZD55-IL-24 increases as injection times increase in both of these two models. However, no obvious increase of efficacy is observed as the dose of each injection increases. Our further investigation reveals that the administration strategy of sustained ZD55-IL-24 therapy can achieve a better therapeutic effect than the traditional administration strategy of short-term ZD55-IL-24 therapy. Furthermore, there is no need to inject every day; every 2 or 3 days of injection achieves an equivalent therapeutic efficacy. Finally, we find that the sustained rather than the traditional short-term ZD55-IL-24 therapy can synergize with anti-PD-1 therapy to reject tumors in B16-bearing immunocompetent mouse model. These findings suggest that the past administration strategy of ZD55-IL-24 is in fact suboptimal and the antitumor efficacy can be further enhanced through administration strategy optimization. This study might shed some light on the development of clinically applicable administration regimens for ZD55-IL-24 therapy.

ASK1-JNK signaling cascade mediates Ad-ST13-induced apoptosis in colorectal HCT116 cells.

ST13, a co-factor of heat shock protein, has shown potential antitumor efficacy for colorectal cancer in our previous study. However, the molecular mechanisms governing ST13-induced apoptosis are poorly understood. Here, we demonstrate that Ad-ST13 (ST13 mediated by adenovirus) activates apoptosis signal-regulated kinase (ASK1) and c-Jun N-terminal kinase (JNK) but not p38 (mitogen-activated protein kinase) in human colorectal HCT116 cells. Ad-ST13 also increases extracellular-regulated kinase (ERK) phosphorylation levels, but the change is due to adenovirus replication. Overexpression of ST13 also increases the transcription activity of AP-1. Blocking ASK1-JNK pathway affects Ad-ST13-mediated colorectal cell apoptosis, decreases the release of cytochrome c in cytoplasm and caspase activation. Because ASK1 is known to contain a tetratricopeptide repeat (TPR)-acceptor site and ST13 has TPR domain, we found the interaction between ST13 and ASK1. These results strongly indicate Ad-ST13 triggers colorectal cell apoptosis via ASK1-JNK signaling cascade.

The armed oncolytic adenovirus ZD55-IL-24 eradicates melanoma by turning the tumor cells from the self-state into the nonself-state besides direct killing.

ZD55-IL-24 is similar but superior to the oncolytic adenovirus ONYX-015, yet the exact mechanism underlying the observed therapeutic effect is still not well understood. Here we sought to elucidate the underlying antitumor mechanism of ZD55-IL-24 in both immunocompetent and immunocompromised mouse model. We find that ZD55-IL-24 eradicates established melanoma in B16-bearing immunocompetent mouse model not through the classic direct killing pathway, but mainly through the indirect pathway of inducing systemic antitumor immunity. Inconsistent with the current prevailing view, our further results suggest that ZD55-IL-24 can induce antitumor immunity in B16-bearing immunocompetent mouse model in fact not due to its ability to lyse tumor cells and release the essential elements, such as tumor-associated antigens (TAAs), but due to its ability to put a "nonself" label in tumor cells and then turn the tumor cells from the "self" state into the "nonself" state without tumor cell death. The observed anti-melanoma efficacy of ZD55-IL-24 in B16-bearing immunocompetent mouse model was practically caused only by the viral vector. In addition, we also notice that ZD55-IL-24 can inhibit tumor growth in B16-bearing immunocompetent mouse model through inhibiting angiogenesis, despite it plays only a minor role. In contrast to B16-bearing immunocompetent mouse model, ZD55-IL-24 eliminates established melanoma in A375-bearing immunocompromised mouse model mainly through the classic direct killing pathway, but not through the antitumor immunity pathway and anti-angiogenesis pathway. These findings let us know ZD55-IL-24 more comprehensive and profound, and provide a sounder theoretical foundation for its future modification and drug development.

Potent anti-hepatoma efficacy of HCCS1 via dual tumor-targeting gene-virotherapy strategy.

We previously demonstrated that hepatocellular carcinoma suppressor 1 (HCCS1) exerts potent anti-tumor activity. In this study, we constructed a new dual tumor-targeting oncolytic adenovirus vector, PD55-HCCS1, in which E1A was driven by the promoter of progression elevated gene-3, which is hepatoma-specific, and a CMV-HCCS1 expression cassette replaced E1B55. The PD55-HCCS1-mediated selective expression of E1A and HCCS1 in hepatoma cells and tumor-selective cytotoxicity in vitro and in vivo demonstrated the strongest inhibition of BEL-7404 cell xenografts in nude mice among a number of control Ad vectors. These data indicated the efficacy and safety of the PD55-HCCS1 system for HCC treatment.

Complete elimination of colorectal tumor xenograft by combined manganese superoxide dismutase with tumor necrosis factor-related apoptosis-inducing ligand gene virotherapy.

Manganese superoxide dismutase (MnSOD) is a latent tumor suppressor gene. To investigate the therapeutic effect of MnSOD and its mechanisms, a replication-competent recombinant adenovirus with E1B 55-kDa gene deletion (ZD55) was constructed, and human MnSOD and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) genes were inserted to form ZD55-MnSOD and ZD55-TRAIL. ZD55-MnSOD exhibited an inhibition in tumor cell growth approximately 1,000-fold greater than Ad-MnSOD. ZD55-TRAIL was shown to induce the MnSOD expression in SW620 cells. Accordingly, by the combined use of ZD55-MnSOD with ZD55-TRAIL (i.e., "dual gene virotherapy"), all established colorectal tumor xenografts were completely eliminated in nude mice. The evidence exists that the MnSOD overexpression led to a slower tumor cell growth both in vitro and in vivo as a result of apoptosis caused by MnSOD and TRAIL overexpression after adenoviral transduction. Our results showed that the production of hydrogen peroxide derived from MnSOD dismutation activated caspase-8, which might down-regulate Bcl-2 expression and induce Bax translocation to mitochondria. Subsequently, Bax translocation enhanced the release of apoptosis-initiating factor and cytochrome c. Cytochrome c finally triggered apoptosis by activating caspase-9 and caspase-3 in apoptotic cascade. Bax-mediated apoptosis seems to be dependent on caspase-8 activation because the inhibition of caspase-8 prevented Bid processing and Bax translocation. In conclusion, our dual gene virotherapy completely eliminated colorectal tumor xenografts via enhanced apoptosis, and this novel strategy points toward a new direction of cancer treatment.

Suppression of colorectal tumor growth by regulated survivin targeting.

A major goal in cancer gene therapy is to develop efficient gene transfer protocols that allow tissue-specific and tightly regulated expression of therapeutic genes. The ideal vector should efficiently transduce cancer cells with minimal toxicity on normal tissues and persistently express foreign genes. One of the most promising regulatory systems is the mifepristone/RU486-regulated system, which has much lower basal transcriptional activity and high inducibility. In this work, we modified this system by incorporating a cancer-specific promoter, the human telomerase reverse transcriptase (hTERT) promoter. By utilizing hTERT promoter to control the regulator, RU486 could specifically induce the expression of foreign genes in cancer cells but not in normal cells. In the context of this system, a dominant negative mutant of survivin (surDN) was controllably expressed in colorectal tumor cells. The surDN expression induced by RU486 showed a dosage- and time-dependent pattern. Regulated expression of surDN caused caspase-dependent apoptosis in colorectal tumor cells but had little effect on normal cells. Analysis of cell viability showed that RU486-induced expression of surDN suppressed colorectal tumor cell growth and had synergic effect in combination with chemotherapeutic agents. The potential of this system in cancer therapy was evaluated in experimental animals. Tumor xenograft models were established in nude mice with colorectal tumor cells, and RU486 was intraperitoneally administered. The results showed that conditional expression of surDN efficiently inhibited tumor growth in vivo and prolonged the life of tumor-burdened mice. Synergized with the chemotherapeutic drug cisplatin, regulated surDN expression completely suppressed tumor growth. These results indicated that this modified RU486-regulated system could be useful in cancer-targeting therapy.

Adenoviral vector expressing CYLD augments antitumor activity of TRAIL by suppression of NF-kappaB survival signaling in hepatocellular carcinoma.

UNLABELLED: CYLD is a tumor suppressor gene related to cylindroma and is negative regulator of NF-kappaB. However, antitumor effect of CYLD has not been reported. The activation of NF-kappaB induced by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) renders hepatocellular carcinoma (HCC) resistant to TRAIL-mediated cell apoptosis. Here we described that the adenoviral vector expressing CYLD (Ad/hTERT-CYLD) augmented the cytotoxicity of TRAIL in HCC cells by negatively regulating NF-kappaB activity since CYLD could reverse the ubiquitination of TNF receptor-associated factor 2 (TRAF2) and interact with the IkappaB kinasegamma (IKKgamma). The combined treatment of Ad/hTERT-CYLD and a conditionally replicating adenovirus carrying TRAIL gene (ZD55-TRAIL) induced rapid and potent apoptosis in HCC cells, characterized by activation of caspase-3, caspase-8, PARP and the reduction of X-linked inhibitor of apoptosis protein (XIAP). In animal study, the combined treatment could eradicate the BEL7404 xenograft tumors. In contrast, treatment with Ad/hTERT-CYLD or ZD55-TRAIL alone achieved less antitumor effect. IN CONCLUSION: CYLD inhibits TRAIL-mediated NF-kappaB activation and enhances the sensitivity of HCC cells to TRAIL-triggered apoptosis. The combined delivery of Ad/hTERT-CYLD and ZD55-TRAIL may be a new useful strategy for HCC or other tumor cells with enhanced NF-kappaB activity.

Potent antitumor activity of oncolytic adenovirus expressing mda-7/IL-24 for colorectal cancer.

It has been demonstrated that interleukin 24 (IL-24, also called melanoma differentiation associated gene 7) exerts antitumor activity. In this study, we investigated whether oncolytic adenovirus-mediated gene transfer of IL-24 could induce strong antitumor activity. A tumor-selective replicating adenovirus expressing IL-24 (ZD55-IL-24) was constructed by insertion of an IL-24 expression cassette into the ZD55 vector, which is based on deletion of the adenoviral E1B 55-kDa gene. ZD55-IL-24 could express substantially more IL-24 than Ad-IL-24 because of replication of the vector. It has been shown that ZD55-IL-24 exerted a strong cytopathic effect and significant apoptosis in tumor cells with p53 dysfunction. Moreover, no cytotoxic and apoptotic effects could be seen in normal cells infected with ZD55-IL-24. Expression of IL-24 did not interfere with viral replication induced by oncolytic adenovirus. Activation of caspase 3 and caspase 9, and induction of bax gene expression, were involved in tumor cell apoptosis induced by ZD55-IL-24. Treatment of established tumors with ZD55-IL-24 showed much stronger antitumor activity than that induced by ONYX-015 or Ad-IL- 24. These data indicated that oncolytic adenovirus expressing IL-24 could exert potential antitumor activity and offer a novel approach to cancer therapy.

Suppression of morphine withdrawal syndrome by interleukin-2 and its gene.

The naloxone-precipitated withdrawal syndrome in mice and rats after intrathecal injection of recombinant human interleukin-2 protein (rIL-2) or its gene was studied. The results showed that rIL-2 could significantly decrease the number of jumps in mice. In rats, rIL-2 significantly suppressed irritating, diarrhea, weight loss, abnormal posture and salivation. Tendencies towards reductions in teeth chewing and dog-shaking were also observed. Furthermore, pcDNA3-IL-2 (8 microg DNA) had a similar effect as 1x10 IU rIL-2 protein on inhibition of morphine withdrawal syndrome in mice, and the expression of rIL-2 protein in spinal cord could be detected for 6 days. These findings provided further evidence for the neuroregulatory function of an immunological molecule such as IL-2.

A dual yet opposite growth-regulating function of miR-204 and its target XRN1 in prostate adenocarcinoma cells and neuroendocrine-like prostate cancer cells.

Androgen deprivation therapy in prostate cancer (PCa) causes neuroendocrine differentiation (NED) of prostatic adenocarcinomas (PAC) cells, leading to recurrence of PCa. Androgen-responsive genes involved in PCa progression including NED remain largely unknown. Here we demonstrated the importance of androgen receptor (AR)-microRNA-204 (miR-204)-XRN1 axis in PCa cell lines and the rat ventral prostate. Androgens downregulate miR-204, resulting in induction of XRN1 (5'-3' exoribonuclease 1), which we identified as a miR-204 target. miR-204 acts as a tumor suppressor in two PAC cell lines (LNCaP and 22Rv1) and as an oncomiR in two neuroendocrine-like prostate cancer (NEPC) cell lines (PC-3 and CL1). Importantly, overexpression of miR-204 and knockdown of XRN1 inhibited AR expression in PCa cells. Repression of miR-34a, a known AR-targeting miRNA, contributes AR expression by XRN1. Thus we revealed the AR-miR-204-XRN1-miR-34a positive feedback loop and a dual function of miR-204/XRN1 axis in prostate cancer.

Enhanced suicide gene therapy by chimeric tumor-specific promoter based on HSF1 transcriptional regulation.

Two tandem cassettes, one containing the telomerase reverse transcriptase gene (hTERT) promoter upstream of a constitutively activated form of heat shock transcription factor 1 (cHSF1) and followed by the other containing the heat shock protein 70B (hsp70B) promoter (HSE) upstream of the cytosine deaminase (CD) gene, could greatly enhance the efficiency of CD gene therapy while retaining tumor specificity in vitro and in vivo. This hTERT-cHSF1/HSE promoter could restrict gene expression in tumor cells and was about 1.5-3-fold more potent than the cytomegalovirus (CMV) promoter. hTERT-cHSF1/HSE-CD transfection led to tumor cells more sensitive to 5-fluorocytosine compared with hTERT-CD and its toxicity was comparable to that of CMV-CD. Besides enhancement of promoter activity, cHSF1 overexpression itself could enhance the bystander effect of CD gene therapy that could be reversed by anti-Fas antibody. This system also led to activation of stress-related genes such as hsp70 in tumor cells, which in the presence of cell killing by the cytotoxic gene is a highly immunostimulatory event. Furthermore, a more potent anti-tumor effect of hTERT-cHSF1/HSE-CD was observed in nude mice inoculated with Bcap37 cells. No obvious activity of the hTERT-cHSF1/HSE promoter was observed in normal tissues after intravenous administration. These results indicate that the hTERT-cHSF1/HSE promoter is highly tumor-specific and strong with potential application in targeted gene therapy, and therefore may be useful for construction of vectors for systemic therapy.

Combination of Targeting Gene-ViroTherapy with 5-FU enhances antitumor efficacy in malignant colorectal carcinoma.

To improve the therapeutic effect of ONYX015, an E1B55kD-deleted replication-competent adenovirus, ZD55 was constructed and armed with the therapeutic gene hTRAIL to form ZD55-hTRAIL, which was used for cancer therapy and which we call Targeting Gene-ViroTherapy. In vitro experiments with SW620, HCT116, and HT29 colorectal carcinoma cell lines demonstrated that they were all sensitive to ZD55-hTRAIL, and especially sensitive to ZD55-hTRAIL plus 5-fluorouracil (5-FU) treatment. In the SW620 xenograft tumor model, various treatment groups showed marked differences at week 11, with the tumor volume for the phosphate-buffered saline (PBS) treatment group >1700 mm3, for 5-FU > 1300 mm3, for ONYX015 1051.3 mm3, for ZD55-hTRAIL 600.05 mm3, and for ZD55-hTRAIL plus 5-FU 230.2 mm3. At the end of week 14, tumor-bearing mice in the other groups almost all died, whereas all the mice in the combined treatment group were alive, with one mouse tumor free. By transmission electron microscopy (TEM) assay, most tumor cells treated with ONYX015 or with ZD55-hTRAIL singly or in combination with 5-FU were lysed due to viral propagation. RT-PCR analysis and immunohistochemistry examination revealed that hTRAIL was expressed in ZD55-hTRAIL-treated SW620 tumor tissue. Furthermore, no detectable hepatoxicity was found by serum enzyme level analysis. These results suggest that ZD55-hTRAIL alone or in combination with 5-FU may have potential clinical implications.

Interleukin-2 gene has superior antinociceptive effects when delivered intrathecally.

The antinociceptive effect of interleukin-2 gene on rat carrageenan-induced pain was explored using different delivery methods. Intrathecal (i.t.) or plantar s.c. delivery of plasmid harbouring the interleukin-2 gene produced a marked antinociceptive effect, which was maintained up to 6 days; the administration of recombinant human interleukin-2 only had a transitory effect. The antinociceptive effect lasted longer and was more potent when the interleukin-2 gene was administered i.t. than when delivered s.c. The effect of the interleukin-2 gene was related to its protein expression, was dose dependent, and could be potentiated by liposome. The results suggest that the interleukin-2 gene has a good prospect for clinical use.