Combination interleukin-2 and interleukin-12 induces severe gastrointestinal toxicity and epithelial cell apoptosis in mice

Interleukin-12 as an in situ cancer vaccine component: a review

Interleukin-12 (IL-12) is a type I cytokine involved in both innate and adaptive immunity that stimulates T and natural killer cell activity and induces interferon gamma production. IL-12 has been identified as a potential immunotherapeutic component for combinatorial cancer treatments. While IL-12 has successfully been used to treat a variety of cancers in mice, it was associated with toxicity when administered systemically in cancer patients. In this review, we discuss the research findings and progress of IL-12 used in combination with other cancer treatment modalities. We describe different methods of IL-12 delivery, both systemic and local, and ultimately highlight the potential of an in situ vaccination approach for minimizing toxicities and providing antitumor efficacy. This review offers a basis for pursuing an in situ vaccine approach that may eventually allow IL-12 to be more readily integrated as an immunotherapy into the clinical treatment of cancers.

Anchoring of intratumorally administered cytokines to collagen safely potentiates systemic cancer immunotherapy

The clinical application of cytokine therapies for cancer treatment remains limited due to severe adverse reactions and insufficient therapeutic effects. Although cytokine localization by intratumoral administration could address both issues, the rapid escape of soluble cytokines from the tumor invariably subverts this effort. We find that intratumoral administration of a cytokine fused to the collagen-binding protein lumican prolongs local retention and markedly reduces systemic exposure. Combining local administration of lumican-cytokine fusions with systemic immunotherapies (tumor-targeting antibody, checkpoint blockade, cancer vaccine, or T cell therapy) improves efficacy without exacerbating toxicity in syngeneic tumor models and the Braf^V600E /Pten^fl/fl genetically engineered melanoma model. Curative abscopal effects on noncytokine-injected tumors were also observed as a result of a protective and systemic CD8⁺ T cell response primed by local therapy. Cytokine collagen-anchoring constitutes a facile, tumor-agnostic strategy to safely potentiate otherwise marginally effective systemic immunotherapies.

Live and heat-killed Lactobacillus rhamnosus GG upregulate gene expression of pro-inflammatory cytokines in 5-fluorouracil-pretreated Caco-2 cells

PURPOSE

This study investigates whether post-chemotherapeutic use of live and heat-killed Lactobacillus rhamnosus GG can modulate the expression of three pro-inflammatory cytokines in 5-fluorouracil (5-FU)-induced intestinal mucositis in vitro.

METHODS

Live L. rhamnosus GG and heat-killed L. rhamnosus GG were observed using scanning electron microscopy. To establish the duration required for optimal expression of tumor necrosis factor-α (TNF-α), monocyte chemotactic protein-1 (MCP-1), and interleukin-12 (IL-12), 5 μM of 5-FU was selected to treat 10-day-old Caco-2 cells for 4, 6, 8, and 24 h. Caco-2 cells were treated with 5-FU (5 μM) for 4 h, followed by the administration of live L. rhamnosus GG (multiplicity of infection = 25), and heat-killed L. rhamnosus GG for 2 and 4 h. Finally, total cellular RNA was isolated to quantify mRNA expression of TNF-α, MCP-1, and IL-12 using real-time PCR.

RESULTS

The results demonstrated that heat-killed L. rhamnosus GG remained structurally intact with elongation. A biphasic upregulated expression of TNF-α, MCP-1, and IL-12 was observed in 5-FU-treated Caco-2 cells at 4 and 24 h. Compared to non-L. rhamnosus GG controls in 5-FU-pretreated Caco-2 cells, a 2-h treatment of heat-killed L. rhamnosus GG significantly upregulated the MCP-1 expression (p < 0.05), and both live and heat-killed L. rhamnosus GG treatments lasting 4 h upregulated the TNF-α and MCP-1 expression (p < 0.05). Only live L. rhamnosus GG upregulated the IL-12 expression (p < 0.05).

CONCLUSIONS

Post-chemotherapeutic use of live or heat-killed L. rhamnosus GG can upregulate the gene expression of 5-FU-induced pro-inflammatory cytokines in Caco-2 cells. Human intestinal epithelium may be vulnerable to the post-chemotherapeutic use of L. rhamnosus GG in 5-FU-induced mucositis that requires further in vivo studies for clarification.

Mechanical disruption of tumors by iron particles and magnetic field application results in increased anti-tumor immune responses

The primary tumor represents a potential source of antigens for priming immune responses for disseminated disease. Current means of debulking tumors involves the use of cytoreductive conditioning that impairs immune cells or removal by surgery. We hypothesized that activation of the immune system could occur through the localized release of tumor antigens and induction of tumor death due to physical disruption of tumor architecture and destruction of the primary tumor in situ. This was accomplished by intratumor injection of magneto-rheological fluid (MRF) consisting of iron microparticles, in Balb/c mice bearing orthotopic 4T1 breast cancer, followed by local application of a magnetic field resulting in immediate coalescence of the particles, tumor cell death, slower growth of primary tumors as well as decreased tumor progression in distant sites and metastatic spread. This treatment was associated with increased activation of DCs in the draining lymph nodes and recruitment of both DCs and CD8(+)T cells to the tumor. The particles remained within the tumor and no toxicities were observed. The immune induction observed was significantly greater compared to cryoablation. Further anti-tumor effects were observed when MRF/magnet therapy was combined with systemic low dose immunotherapy. Thus, mechanical disruption of the primary tumor with MRF/magnetic field application represents a novel means to induce systemic immune activation in cancer.

Necrotizing enterocolitis: old problem with new hope

The incidence of necrotizing enterocolitis (NEC) and mortality rate associated with this disease are not decreasing despite more than three decades of intensive research investigation and advances in neonatal intensive care. Although the etiology of NEC is not clearly elucidated, the most accepted hypothesis at present is that enteral feeding in the presence of intestinal hypoxia-ischemia-reperfusion, and colonization with pathogens provokes an inappropriately accentuated inflammatory response by the immature intestinal epithelial cells of the preterm neonate. However, delayed colonization of commensal flora with dysbiotic flora with a predominance of pathologic microorganisms plays a fundamental role in the pathogenesis of NEC. Recent studies have further identified that NEC infants have less diverse flora compared to age-matched controls without NEC. Increased gastric residual volume may be an early sign of NEC. An absolute neutrophil count of <1.5 × 10(9)/L and platelets below 100 × 10(9)/L are associated with an increased risk for mortality and gastrointestinal morbidity. Nonspecific supportive medical management should be initiated promptly. Sudden changes in vital signs such as tachycardia or impending shock may indicate perforation. A recent meta-analysis investigating using probiotics for prevention of NEC with a total of 2176 preterm very low birth weight infants found a success rate of just 1/25. Careful monitoring of the residual volume, and of serious changes in hemograms and vital signs may help in early diagnosis and prediction of when to perform medical or early surgical intervention. In term of prevention, administration of oral probiotics containing Bifidobacterium and Lactobacillus is a simple and safe method that attempts to early establish of commensal flora balance to inhibit pathogenic flora and an inflammatory response.

Intratumoral immunotherapy of established solid tumors with chitosan/IL-12

IL-12 is a potent antitumor cytokine that exhibits significant clinical toxicities after systemic administration. We hypothesized that intratumoral (i.t.) administration of IL-12 coformulated with the biodegradable polysaccharide chitosan could enhance the antitumor activity of IL-12 while limiting its systemic toxicity. Noninvasive imaging studies monitored local retention of IL-12, with and without chitosan coformulation, after i.t. injection. Antitumor efficacy of IL-12 alone and IL-12 coformulated with chitosan (chitosan/IL-12) was assessed in mice bearing established colorectal (MC32a) and pancreatic (Panc02) tumors. Additional studies involving depletion of immune cell subsets, tumor rechallenge, and CTL activity were designed to elucidate mechanisms of regression and tumor-specific immunity. Coformulation with chitosan increased local IL-12 retention from 1 to 2 days to 5 to 6 days. Weekly i.t. injections of IL-12 alone eradicated ≤10% of established MC32a and Panc02 tumors, while i.t. chitosan/IL-12 immunotherapy caused complete tumor regression in 80% to 100% of mice. Depletion of CD4(+) or Gr-1(+) cells had no impact on chitosan/IL-12-mediated tumor regression. However, CD8(+) or NK cell depletion completely abrogated antitumor activity. I.t. chitosan/IL-12 immunotherapy generated systemic tumor-specific immunity, as >80% of mice cured with i.t. chitosan/IL-12 immunotherapy were at least partially protected from tumor rechallenge. Furthermore, CTLs from spleens of cured mice lysed MC32a and gp70 peptide-loaded targets. Chitosan/IL-12 immunotherapy increased local retention of IL-12 in the tumor microenvironment, eradicated established, aggressive murine tumors, and generated systemic tumor-specific protective immunity. Chitosan/IL-12 is a well-tolerated, effective immunotherapy with considerable potential for clinical translation.

Transcriptome analysis and gene expression profiles of early apoptosis-related genes in Streptococcus pyogenes-infected epithelial cells

Epithelial cells are the initial sites of host invasion by group A Streptococcus pyogenes (GAS), and GAS infection of epithelial cells has been suggested to induce apoptosis. We previously reported that the induction of apoptosis is strongly associated with the protein F1-mediated invasion. We present here the gene expression profiles of the human epithelial HEp-2 cells during GAS-induced apoptosis, using serial gene analysis of expression (SAGE) analysis and macroarray analysis of apoptosis-related genes. Serial gene analysis of expression revealed the downregulation of voltage-dependent anion channels 1 and 2 genes and the upregulation of the cytochrome c oxidase and calcium binding protein genes (calpactin, calgizzarin and programmed cell death 6). Macroarray analysis and quantitative RT-PCR analysis also revealed that the genes for IL-1beta, IL-12 p35, IL12 p40, and GM-CSF are also markedly induced by GAS invasion. Furthermore, caspase-1, -9, and -14 genes are significantly upregulated during GAS invasion. These observations indicated that apoptosis associated with GAS invasion is mainly induced by mitochondrial dysfunction and calcium regulation as well as by stress, and that these transcriptional controls may regulate the cellular response to GAS invasion.

Insertion of interleukin-2 (IL-2) and interleukin-12 (IL-12) genes into vaccinia virus results in effective anti-tumor responses without toxicity

Identification of novel tumor-associated antigens (TAA) capable of eliciting T-cell responses has renewed interest in the development of anti-tumor vaccines. The insertion of genes encoding specific TAA into a vaccinia virus (rVV) is one approach to vaccination since large amounts of foreign DNA can be stably integrated into the poxvirus genome. Recent reports have documented an increased therapeutic effectiveness of poxvirus-based vaccines when additional treatment with cytokines, such as interleukin-2 (IL-2) or interleukin-12 (IL-12) were used, but the combination of these cytokines as adjuvants for a rVV encoding TAA have not been previously reported. The combination of IL-2 and IL-12 at single regimen systemic doses was toxic and sometimes fatal, manifesting largely as segmental epithelial apoptosis of the large bowel. To explore the local delivery of both cytokines to the site of vaccination, the genes encoding IL-2 and IL-12 were inserted into vaccinia virus along with a model tumor antigen gene. This construct contained five heterologous genes: LacZ (the model antigen), gpt (reporter gene), IL-2, and the two IL-12 subunit genes (p35 and p40). Treatment with this recombinant virus resulted in a reduced number of pulmonary metastases, improved survival, and minimal toxicity in a murine tumor model. The use of vaccinia virus for the insertion of other heterologous gene combinations may provide a powerful and less toxic approach for novel vaccination strategies in the treatment and prevention of cancer.