An International Registry of Peritoneal Carcinomatosis from Appendiceal Goblet Cell Carcinoma Treated with Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy

PURPOSE

Peritoneal carcinomatosis from appendiceal goblet cell carcinoma (A-GCC) is a rare and aggressive form of appendiceal tumor. Cytoreductive surgery (CRS) and hyperthermic intra peritoneal chemotherapy (HIPEC) was reported as an interesting alternative regarding survival compared to surgery without HIPEC and/or systemic chemotherapy. Our aim was to evaluate the impact of CRS and HIPEC for patients presenting A-GCC through an international registry.

METHODS

A prospective multicenter international database was retrospectively searched to identify all patients with A-GCC tumor and peritoneal metastases who underwent CRS and HIPEC through the Peritoneal Surface Oncology Group International (PSOGI). The post-operative complications, long-term results, and principal prognostic factors were analyzed.

RESULTS

The analysis included 83 patients. After a median follow-up of 47 months, the median overall survival (OS) was 34.6 months. The 3- and 5-year OS was 48.5% and 35.7%, respectively. Patients who underwent complete macroscopic CRS had a significantly better survival than those treated with incomplete CRS. The 5-year OS was 44% and 0% for patients who underwent complete, and incomplete CRS, respectively (HR 9.65, p < 0.001). Lymph node involvement and preoperative chemotherapy were also predictive of a worse prognosis. There were 3 postoperative deaths, and 30% of the patients had major complications.

CONCLUSION

CRS and HIPEC may increase long-term survival in selected patients with peritoneal metastases of A-GCC origin, especially when complete CRS is achieved. Ideally, randomized control trials or more retrospective data are needed to confirm CRS and HIPEC as the gold standard in this pathology.

Risk factors and outcomes of conversion in minimally invasive distal pancreatectomy: a systematic review

Purpose

The reported conversion rates for minimally invasive distal pancreatectomy (MIDP) range widely from 2 to 38%. The identification of risk factors for conversion may help surgeons during preoperative planning and patient counseling. Moreover, the impact of conversion on outcomes of MIDP is unknown.

Methods

A systematic review was conducted as part of the 2019 Miami International Evidence-Based Guidelines on Minimally Invasive Pancreas Resection (IG-MIPR). The PubMed, Cochrane, and Embase databases were searched for studies concerning conversion to open surgery in MIDP.

Results

Of the 828 studies screened, eight met the eligibility criteria, resulting in a combined dataset including 2592 patients after MIDP. The overall conversion rate was 17.1% (range 13.0–32.7%) with heterogeneity between studies associated with the definition of conversion adopted. Only one study divided conversion into elective and emergency conversion. The main indications for conversion were vascular involvement (23.7%), concern for oncological radicality (21.9%), and bleeding (18.9%). The reported risk factors for conversion included a malignancy as an indication for surgery, the proximity of the tumor to vascular structures in preoperative imaging, higher BMI or visceral fat, and multi-organ resection or extended resection. Contrasting results were seen in terms of blood loss and length of stay in comparing converted MIDP and completed MIDP patients.

Conclusion

The identified risk factors for conversion from this study can be used for patient selection and counseling. Surgeon experience should be considered when contemplating MIDP for a complex patient. Future studies should divide conversion into elective and emergency conversion.

An Unexpected Etiology of Pancreatic Panniculitis: A Case Report

BACKGROUND

Pancreatic panniculitis is a rare cause of subcutaneous fat necrosis secondary to elevated serum levels of pancreatic enzymes. It is most often associated with pancreatic acinar cell carcinoma, but has also been seen in patients with pancreatitis.

CASE REPORT

We present a case of a 64 year old Caucasian man without symptoms of pancreatitis who presents with pancreatic panniculitis manifesting in multiple subcutaneous ulcerating nodules of the bilateral lower extremities, discovered to have a previously unreported etiology for this condition. He had no evidence of pancreatitis or malignancy, but instead a pancreatic-portal fistula resulting in panniculitis.

CONCLUSION

Peripancreatic vascular lesions must also be considered in the differential diagnosis of pancreatic panniculitis. The diagnosis, pathology, and treatment of pancreatic panniculitis are reviewed herein.

The receptor for advanced glycation end products (RAGE) enhances autophagy and neutrophil extracellular traps in pancreatic cancer

Neutrophil extracellular traps (NETs) are formed when neutrophils expel their DNA, histones and intracellular proteins into the extracellular space or circulation. NET formation is dependent on autophagy and is mediated by citrullination of histones to allow for unwinding and subsequent expulsion of DNA. NETs play an important role in the pathogenesis of several sterile inflammatory diseases, including malignancy, therefore we investigated the role of NETs in the setting of pancreatic ductal adenocarcinoma (PDA). Neutrophils isolated from two distinct animal models of PDA had an increased propensity to form NETs following stimulation with platelet activating factor (PAF). Serum DNA, a marker of circulating NET formation, was elevated in tumor bearing animals as well as in patients with PDA. Citrullinated histone H3 expression, a marker of NET formation, was observed in pancreatic tumors obtained from murine models and patients with PDA. Inhibition of autophagy with chloroquine or genetic ablation of RAGE resulted in decreased propensity for NET formation, decreased serum DNA, and decreased citrullinated histone H3 expression in the pancreatic tumor microenvironment. We conclude that NETs are upregulated in pancreatic cancer through RAGE dependent/autophagy pathways.

RAGE is essential for oncogenic KRAS-mediated hypoxic signaling in pancreatic cancer

A hypoxic tumor microenvironment is characteristic of many cancer types, including one of the most lethal, pancreatic cancer. We recently demonstrated that the receptor for advanced glycation end products (RAGE) has an important role in promoting the development of pancreatic cancer and attenuating the response to chemotherapy. We now demonstrate that binding of RAGE to oncogenic KRAS facilitates hypoxia-inducible factor 1 (HIF1)α activation and promotes pancreatic tumor growth under hypoxic conditions. Hypoxia induces NF-κB-dependent and HIF1α-independent RAGE expression in pancreatic tumor cells. Moreover, the interaction between RAGE and mutant KRAS increases under hypoxia, which in turn sustains KRAS signaling pathways (RAF-MEK-ERK and PI3K-AKT), facilitating stabilization and transcriptional activity of HIF1α. Knock down of RAGE in vitro inhibits KRAS signaling, promotes HIF1α degradation, and increases hypoxia-induced pancreatic tumor cell death. RAGE-deficient mice have impaired oncogenic KRAS-driven pancreatic tumor growth with significant downregulation of the HIF1α signaling pathway. Our results provide a novel mechanistic link between NF-κB, KRAS, and HIF1α, three potent molecular pathways in the cellular response to hypoxia during pancreatic tumor development and suggest alternatives for preventive and therapeutic strategies.

A phase I trial of isolated hepatic perfusion (IHP) using 5-FU and oxaliplatin in patients with unresectable isolated liver metastases from colorectal cancer

BACKGROUND

Isolated hepatic perfusion (IHP) with melphalan is an established approach for patients with unresectable metastatic liver lesions. This study determined the safety and maximum tolerated dose (MTD) of 5-FU with oxaliplatin via IHP.

METHODS

Standard 3 × 3 Phase I design. Subjects with unresectable isolated CRC liver metastases scheduled for HAI pump were eligible. IHP used fixed-dose oxaliplatin with escalating 5-FU doses. Toxicity (CTCAE v 4.0) and response (RECIST), progression-free survival, and overall survival (OS) were assessed. Systemic and IHP plasma PK of 5-FU, anabolites, and platinum were determined.

RESULTS

All 12 patients had received ≥ 1 line of pre-IHP chemotherapy. There were 4 grade 3 serious adverse events (33.3 %) and 1 grade 4 event (8.3 %). Also, 2 dose-limiting toxicities occurred at DL2 at 300 mg/m(2), resulting in expansion of DL1 at 200 mg/m(2) 5-FU, the eventual MTD. At 6-month follow-up, 9 patients (82 %) demonstrated partial response, while 2 (18 %) exhibited stable disease. Also, 64 % of patients demonstrated a >50 % decrease in CEA. The 1- and 2-year OS probabilities were 90.9 and 71.6 %, respectively, with median follow-up of 24 months. IHP exposures (AUC0-60 min) were 10.9 ± 4.5 μgPt h/mL, 49.3 ± 30.7 μg h/mL 5-FU (DL1), and 70.5 ± 35.5 μg h/mL 5-FU (DL2). Systemic exposure (AUC0-inf) relative to IHP exposure was negligible for both platinum (1.1 ± 1.5 %) and 5-FU (0.09 ± 0.10 %).

CONCLUSIONS

The MTD for IHP was 200 mg/m(2) 5-FU with 40 mg/m(2) oxaliplatin. Systemic exposure to the agents was minimal during IHP. The response and survival observed warrants assessment in a larger phase II trial.

Robotic-assisted major pancreatic resection

Robotic-assisted major pancreatic resections allow recreation of time-tested open surgical procedures on a minimally invasive platform. Early outcomes from robotic-assisted major pancreatic resections are comparable with those of laparoscopic and open approaches. Robotic assistance has the potential to bring the well-recognized advantages of minimally invasive surgery to major pancreatic resections. Technological innovations and increased surgeon familiarity with this approach will improve, likely leading to greater adoption and acceptance.

The Beclin 1 network regulates autophagy and apoptosis

Beclin 1, the mammalian orthologue of yeast Atg6, has a central role in autophagy, a process of programmed cell survival, which is increased during periods of cell stress and extinguished during the cell cycle. It interacts with several cofactors (Atg14L, UVRAG, Bif-1, Rubicon, Ambra1, HMGB1, nPIST, VMP1, SLAM, IP(3)R, PINK and survivin) to regulate the lipid kinase Vps-34 protein and promote formation of Beclin 1-Vps34-Vps15 core complexes, thereby inducing autophagy. In contrast, the BH3 domain of Beclin 1 is bound to, and inhibited by Bcl-2 or Bcl-XL. This interaction can be disrupted by phosphorylation of Bcl-2 and Beclin 1, or ubiquitination of Beclin 1. Interestingly, caspase-mediated cleavage of Beclin 1 promotes crosstalk between apoptosis and autophagy. Beclin 1 dysfunction has been implicated in many disorders, including cancer and neurodegeneration. Here, we summarize new findings regarding the organization and function of the Beclin 1 network in cellular homeostasis, focusing on the cross-regulation between apoptosis and autophagy.

Morbidity and survival of 32 recurrent ovarian cancer patients treated with aggressive cytoreductive surgery followed by intraperitoneal hyperthermic chemoperfusion

16078

Background: Cytoreductive surgery followed by intraperitoneal hyperthermic chemoperfusion (CS/IPHC) has shown increased survival for patients with recurrent and persistent GI malignancies with peritoneal dissemination. We present our preliminary experience with CS/IPHC as palliative therapy for recurrent ovarian cancer treated at a single institution. Methods: A retrospective review of CS/IPHC for women with recurrent or persistent epithelial ovarian carcinoma previously treated with platinum/taxane chemotherapy at a single institution from 2002–2006 was performed. Each patient had an attempted optimal surgical debulking (volume of residual disease <1 cm) prior to chemoperfusion. IPHC was performed on all patients for 100 minutes at temperatures between 40–42°C with either mitomycin C (40 mg/m2) or cisplatin (100 mg/m2). Post-surgical complications were evaluated. End points analyzed included morbidity, progression free survival, and over all survival. Results: Thirty-two patients were identified, with optimal cytoreductive surgery obtained in 26 (81.3%). Procedures required for cytoreduction included omentectomy (n=16), splenectomy (n=14), colonic resection (n=14), small bowel resection (n=13), ileostomy (n=9), hepatic resection (n=5), partial gastrectomy (n=5), and diaphragmatic stripping (n=3). Over-all morbidity was 65.6%, with major morbidity of 9.4%. There were three mortalities within sixty days of operation. Common morbidities included neutropenia (n=5), ileus (n=5), pleural effusions (n=4), and sepsis (n=4). Median length of stay was 11 days (6 to 47). Nineteen patients had a documented recurrence with a median progression free survival of 8 months (1 to 22). Median survival was 13 months (1 to 54) for these patients with recurrent end stage ovarian cancer. Conclusions: CS/IPHC is associated with high morbidity, but acceptable mortality. In a subset of patients, survival is improved compared to historical controls for recurrent ovarian cancer. A randomized phase II study is planned based on this data.

No significant financial relationships to disclose.

Multianalyte profiling of serum cytokines for detection of pancreatic cancer

Early detection of pancreatic cancer might improve clinical outcome. Significant alterations in the levels of individual serum cytokines have been reported in pancreatic cancer. We hypothesized that a multicytokine panel could serve as biomarkers for pancreatic cancer. To evaluate the diagnostic utility of such a panel, we have utilized a novel multianalyte LabMAP profiling technology that allows simultaneous measurement of multiple markers. In this study, a panel of 31 serological markers including cytokines, chemokines, growth and angiogenic factors in combination with CA 19-9 was analyzed in sera of pancreatic cancer patients, patients with chronic pancreatitis, and matched control healthy subjects. Statistical analysis identified a multicytokine panel that was able to distinguish pancreatic cancer from healthy controls with a sensitivity of 85.7% and specificity of 92.3%, which was superior to performance of CA 19-9 alone. Importantly, a multicytokine panel allowed the discrimination of pancreatic cancer from chronic pancreatitis with high sensitivity of 98% and specificity of 96.4%. In conclusion, we demonstrated that analysis of multiple serum cytokines using a novel LabMAP technology is a promising approach for development of a diagnostic assay for pancreatic cancer.

A new recombinant vaccinia with targeted deletion of three viral genes: its safety and efficacy as an oncolytic virus

To enhance further the safety and efficacy of oncolytic vaccinia virus, we have developed a new virus with targeted deletions of three viral genes encoding thymidine kinase and antiapoptotic/host range proteins SPI-1 and SPI-2 (vSPT). Infection of human and murine tumor cell lines yielded nearly equivalent or a log lower virus recovery in comparison to parental viruses. Viral infection activated multiple caspases in cancer cells but not in normal cells, suggesting infected cells may die via different pathways. In tumor-bearing mice, vSPT recovery from MC38 tumor was slightly reduced in comparison to two parental viruses. However, no virus was recovered from the brains and livers of mice injected with vSPT in contrast to control viruses. vSPT demonstrated significantly lower pathogenicity in nude mice. Systemic delivery of vSPT showed significant tumor inhibition in subcutaneous MC38 tumor, human ovarian A2780 and murine ovarian MOSEC carcinomatosis models; however, the tumor inhibition by vSPT was reduced compared with parental viruses. These results demonstrated that although deletion of these three viral genes further enhanced tumor selectivity, it also weakened the oncolytic potency. This study illustrates the complexity of creating a tumor-selective oncolytic virus by deleting multiple viral genes involved in multiple cellular pathways.

Vaccines for colorectal cancer

Despite recent advances in the treatment of colorectal cancer, the overall survival rate for those patients with advanced locoregional disease remains less than 50%. Although adjuvant systemic chemotherapy has improved survival of these patients, more effective therapies are needed. Immunotherapy is an approach that could have a particular role in the adjuvant therapy of colorectal cancer. There is now convincing evidence that the immune system can specifically recognize and destroy malignant cells. Although both antibody- and T-cell-mediated anti-tumor responses have been documented, the cellular immune response with its direct cytotoxic mechanisms is felt to be the principal anti-tumor arm of the immune system. Analysis of the T cells that recognize tumors has led to the identification and characterization of many tumor-associated antigens including several colorectal antigens. Current approaches to developing a vaccine for colorectal cancer use our expanded understanding of these tumor-associated antigens and the conditions that allow development of an effective cellular immune response to them.

High avidity CTLs for two self-antigens demonstrate superior in vitro and in vivo antitumor efficacy

A majority of the human tumor-associated Ags characterized to date are derived from nonmutated "self"-proteins. Little is currently understood about the nature of the self-reactive lymphocytes that recognize these Ags. We recently characterized two nonmutated tumor-associated Ags for the B16 murine melanoma: tyrosinase-related protein-2 (TRP-2) and the endogenous retroviral envelope protein, p15E. We previously reported that both TRP-2 and p15E reactive CTL could be detected in the spleens of naive animals after a single in vitro stimulation using 10(-5)-10(-6) M of the appropriate Kb-binding 9-amino acid epitope. In this report we show that the CTL found in naive animals are low avidity lymphocytes, that respond only to high concentrations of peptide in vitro. We demonstrate that titration of in vitro-stimulating peptide to limiting concentrations distinguishes qualitative differences in the lymphocyte reactivity to these two Ags between vaccinated and unvaccinated animals. We further demonstrate that in vitro expansion of CTL in either high or low concentrations of stimulating peptide generated CTL cultures with different avidities for the relevant epitopes. CTL expanded in low concentrations demonstrated higher avidity for peptide-pulsed targets and better tumor recognition, when compared to CTL generated in the presence of high concentrations of Ag. More importantly, high avidity CTL demonstrated superior in vivo antitumor activity. These results demonstrate that qualitative differences in the CTL that recognize these two self-Ags are critically important to their in vitro and in vivo anti-tumor efficacy.

Effective eradication of established murine tumors with IL-12 gene therapy using a polycistronic retroviral vector

Our recent studies using IL-12 protein or fibroblasts genetically engineered to secrete IL-12 have demonstrated profound antitumor effects of IL-12 in murine models. The antitumor effects of local, high level IL-12 expression were examined using a retroviral vector, which can express both IL-12 subunits (p35 and p40) and the neomycin phosphotransferase (Neo)-marker gene from a polycistronic message utilizing internal ribosome entry site sequences. All animals intradermally (i.d.) receiving MCA207 murine sarcoma cell line nontransfected or Neo-transfected had progressively growing tumor, whereas all animals injected with MCA207 transfected with IL-12 were tumor free and were subsequently determined to be immune to a rechallenge of nontransfected MCA207 i.d. Similar results were obtained in experiments using the poorly immunogenic MCA102 murine sarcoma cell line. The inoculation of live MCA207-IL-12 tumor cells also caused the regression of contralateral nontransfected MCA207 inoculated either at the same time (80% protection) or up to 3 days before (33% protection) to the therapeutic tumor inoculation. In vivo depletion studies suggest that NK cells and IFN-gamma play important roles in the development of the early phase of the antitumor response, but that T cells (both CD4+ and CD8+) play the major role in the subsequent events, leading to long-term immunity. The potent antitumor effects observed for paracrine gene-delivered administration of IL-12 have thus been confirmed for multiple tumor cell types and in multiple murine strains. We believe that these results support the feasibility of IL-12 gene therapy for the treatment of human cancer.

Effective eradication of established murine tumors with IL-12 gene therapy using a polycistronic retroviral vector

Our recent studies using IL-12 protein or fibroblasts genetically engineered to secrete IL-12 have demonstrated profound antitumor effects of IL-12 in murine models. The antitumor effects of local, high level IL-12 expression were examined using a retroviral vector, which can express both IL-12 subunits (p35 and p40) and the neomycin phosphotransferase (Neo)-marker gene from a polycistronic message utilizing internal ribosome entry site sequences. All animals intradermally (i.d.) receiving MCA207 murine sarcoma cell line nontransfected or Neo-transfected had progressively growing tumor, whereas all animals injected with MCA207 transfected with IL-12 were tumor free and were subsequently determined to be immune to a rechallenge of nontransfected MCA207 i.d. Similar results were obtained in experiments using the poorly immunogenic MCA102 murine sarcoma cell line. The inoculation of live MCA207-IL-12 tumor cells also caused the regression of contralateral nontransfected MCA207 inoculated either at the same time (80% protection) or up to 3 days before (33% protection) to the therapeutic tumor inoculation. In vivo depletion studies suggest that NK cells and IFN-gamma play important roles in the development of the early phase of the antitumor response, but that T cells (both CD4+ and CD8+) play the major role in the subsequent events, leading to long-term immunity. The potent antitumor effects observed for paracrine gene-delivered administration of IL-12 have thus been confirmed for multiple tumor cell types and in multiple murine strains. We believe that these results support the feasibility of IL-12 gene therapy for the treatment of human cancer.

Flow-cytometric determination of peptide-class I complex formation. Identification of p53 peptides that bind to HLA-A2

A novel class I-peptide-binding assay was developed and used to identify a series of peptides derived from the human p53 tumor-suppressor gene product capable of binding the HLA-A2 class I allele. Brief pH 3.3 acid treatment of human cell lines rapidly denatures pre-existing class I complexes, as detected by loss of binding of conformation-dependent mAbs, leaving only free class I heavy chains associated with the viable cell surface. These heavy chains may be induced to refold and be recognized by antibodies (in 2-4 hours) when acid-treated cells are coincubated with exogenous beta 2-microglobulin and peptides capable of binding the relevant class I allele examined. This assay, with a detection limit of 1-10 nM peptide, was used to screen the capacity of a panel of nine peptides bearing HLA-A2-binding motifs and derived from the human p53 tumor-suppressor protein sequence. Eight of the nine peptides bound to, and reconstituted, HLA-A2 on acid-treated cells. This assay system will enable the rapid identification of peptides binding to any class I allele, which is the initial prerequisite for elucidating potential CD8+ T-cell epitopes.

Fibroblasts genetically engineered to secrete interleukin 12 can suppress tumor growth and induce antitumor immunity to a murine melanoma in vivo

Interleukin 12 (IL-12), a disulfide-linked heterodimeric cytokine produced primarily by macrophages, is composed of light (p35) and heavy (p40) chains. It binds to a receptor on T-cells and natural killer cells, promoting the induction of primarily a TH1 response in vitro and in vivo. To determine whether paracrine IL-12 secretion can alter tumor cell growth or promote antitumor immunity, we have developed a delivery system using genetically engineered fibroblasts in murine tumor models. NIH3T3 cells were stably transfected to express 100-240 units/10(6) cells/48 h of IL-12 using expression plasmids carrying both the murine p35 and p40 genes of murine IL-12. The effects of paracrine secretion of IL-12 on tumor establishment and vaccination models were examined using the poorly immunogenic murine melanoma cell line (BL-6) in C57BL/6 mice. To determine the effects of IL-12 on tumor formation, nonirradiated BL-6 cells were inoculated s.c. into C57BL/6 mice admixed with NIH3T3 cells transfected with both subunits of mIL-12 (3T3-IL-12) or with cells transfected with only the neomycin phosphotransferase gene (3T3-Neo). Compared to mice given injections of BL-6 alone, the day of emergence of detectable tumors was significantly delayed in mice given injections of BL-6 admixed with 3T3-IL-12, but not in mice with BL-6 admixed with 3T3-Neo. Effectiveness in this system was related to the amount of IL-12 expressed by the 3T3-IL-12. To determine the ability of locally secreted IL-12 at the tumor site to induce antitumor immunity, 10(6) irradiated tumor cells mixed with 3T3-IL-12 or 3T3-Neo were injected as a vaccine, and the response to a tumor challenge was subsequently examined. With a tumor challenge of less than 1 x 10(5) nonirradiated BL-6 cells, significant delay of establishment of tumor was noted with a relatively small amount of IL-12 secretion (1.2 units/5 x 10(5) cells/48 h). Larger amounts of secreted IL-12 provided no additional therapeutic benefit. Histological examination of tumor inoculum with 3T3-IL-12 secreting a high level of IL-12 showed peritumoral accumulation of macrophages, a characteristic capsule around the tumor composed of palisades of fibroblasts, and decreased numbers of CD4+ cells in the tumor. These results suggest that local delivery of IL-12 inhibits tumor growth in a dose dependent manner but leads to the development of an antitumor immune response when IL-12 is expressed at the tumor site at the relatively small amount indicated above.(ABSTRACT TRUNCATED AT 400 WORDS)

Identification of human melanoma peptides recognized by class I restricted tumor infiltrating T lymphocytes

Using a newly described pH 3.3 acid elution technique, peptides were extracted by denaturation of class I molecules on the surface of human melanomas. HPLC fractionation of this material revealed six T cell epitopes (termed P1-P6) recognized by HLA-A2-restricted, melanoma-specific tumor infiltrating lymphocyte (TIL) lines. Three of these fractions (P1, P2, and P4) appeared to represent shared/immunodominant melanoma Ag recognized in the context of HLA-A2 because they were expressed by 4/4 HLA-A2+ melanoma cell lines and were each recognized by all four oligoclonal HLA-A2-restricted TIL lines examined. Interestingly, P1 and P2 (but not P3-P6) could also be recognized by these same TIL when presented by the HLA-Aw69 class I molecule, which is closely related to HLA-A2. P3, P5, and P6 displayed more restricted expression and were differentially recognized by the four oligoclonal TIL lines. These results suggest that synthetic peptide derived from P1, P2, and P4 sequences (when deduced) may form the basis of effective prophylactic or therapeutic melanoma vaccines by stimulating CD8+ CTL in HLA-A2+ individuals. This approach of identifying T cell epitopes presented by class I molecules should prove generally applicable to the study of other tumors recognized by class I-restricted CTL.

Identification of human melanoma peptides recognized by class I restricted tumor infiltrating T lymphocytes

Using a newly described pH 3.3 acid elution technique, peptides were extracted by denaturation of class I molecules on the surface of human melanomas. HPLC fractionation of this material revealed six T cell epitopes (termed P1-P6) recognized by HLA-A2-restricted, melanoma-specific tumor infiltrating lymphocyte (TIL) lines. Three of these fractions (P1, P2, and P4) appeared to represent shared/immunodominant melanoma Ag recognized in the context of HLA-A2 because they were expressed by 4/4 HLA-A2+ melanoma cell lines and were each recognized by all four oligoclonal HLA-A2-restricted TIL lines examined. Interestingly, P1 and P2 (but not P3-P6) could also be recognized by these same TIL when presented by the HLA-Aw69 class I molecule, which is closely related to HLA-A2. P3, P5, and P6 displayed more restricted expression and were differentially recognized by the four oligoclonal TIL lines. These results suggest that synthetic peptide derived from P1, P2, and P4 sequences (when deduced) may form the basis of effective prophylactic or therapeutic melanoma vaccines by stimulating CD8+ CTL in HLA-A2+ individuals. This approach of identifying T cell epitopes presented by class I molecules should prove generally applicable to the study of other tumors recognized by class I-restricted CTL.

Identification of T-cell epitopes: rapid isolation of class I-presented peptides from viable cells by mild acid elution

A novel method was developed to isolate immunogenic peptides (CD8+ T-cell epitopes) from class I complexes expressed at the cell surface of viable cells. Cells treated at pH 3.3 with citrate-phosphate buffer for periods as short as 15 s remained viable and became phenotypically class I deficient. Qualitative loss of class I determinants was verified both serologically and by the incapacity of acid-treated cells to be lysed by class I-restricted cytolytic T lymphocytes (CTLs) in contrast to non-acid-treated controls. Flow cytometric analysis of acid-treated cells suggests that class I heavy chains remain associated with the cell membrane, while the class I light chain (beta 2-microglobulin) is absent. Since the physical dissociation of beta 2-microglobulin from class I heavy chain is correlated with the release of previously class I-bound peptides, we examined acid-eluted cell-free supernatants for the presence of immunogenic peptides. Peptides were acid eluted from an influenza A strain-infected, HLA-A2+ cell line and were subsequently fractionated by reverse-phase high performance liquid chromatography (RP-HPLC). These fractionated peptides were examined for their capacity to sensitize an HLA-A2+ B cell line to lysis mediated by an influenza A matrix peptide- (Flu M1 57-68) specific, HLA-A2-restricted CTL line. A single peak of biologic activity was identified in HPLC fractions 47 and 48 derived from influenza-infected cells. These fractions contained a peptide of M(r) 968 with a sequence similar to the Flu M1 58-66 sequence GILGFVFTL. The application of this technique to other T-cell-based systems may aid in the definition of peptide epitopes relevant to viral, autoimmune, or neoplastic disorders.

Interleukin-12 promotes the proliferation and cytolytic maturation of immune effectors: implications for the immunotherapy of cancer

Interleukin-12 (IL-12) is a B-cell and monocyte-derived 75 kDa heterodimeric cytokine released early after immune stimulation. It promotes the cytolytic maturation and proliferation of T and natural killer (NK) cells and release of interferon-gamma from these effectors. Furthermore, IL-12 appears to stimulate the production of a Th1 immune response. We have examined the effects of IL-12 on the proliferation and lytic activity of fresh peripheral blood mononuclear cells (PBMCs) and tumor-infiltrating lymphocytes (TILs). IL-12 stimulates proliferation of PBMCs by as much as 10-fold after T-cell receptor (TCR) ligation induced by anti-CD3 or phytohemagglutinin. In contrast, IL-12 promotes only marginal proliferation of resting PBMCs. IL-12 modulates IL-2-induced lymphokine-activated killer (LAK) cell activity: it inhibits IL-2 LAK when added early to culture but augments LAK activity in PBMCs preactivated by IL-12. IL-12 induces the proliferation (three- to fourfold above background) and enhances the cytolytic activity (two- to fourfold) of TIL lines and melanoma-derived, peptide-specific T-cell clones that have been recently restimulated with autologous tumor. These results suggest that IL-12 may serve in vivo to amplify and focus the cellular immune response by selectively inducing the outgrowth and enhancing the lytic potential of T and NK cells that have received the proper coactivation signals.

New biologic agents come to bat for cancer therapy

Biologic therapies are playing an increasingly important role in the treatment of patients with cancer. A better understanding of immune responses to tumors now exists, and more defined reagents are now available including new recombinant cytokines, cultured lymphoid cells of defined specificity, and most recently, vectors containing specific genes that can be introduced either into tumor cells or lymphoid effectors. During this past year, we have observed the reporting of new cytokines identified and tested in humans and the advent of cytokine gene therapy. The successful application of these new reagents either singly or in combination will require significant ingenuity, resources, and intuition over the next decade.

Use of T-Cell Growth Factors (Interleukins 2, 4, 7, 10, and 12) in the Evaluation of T-Cell Reactivity to Melanoma

Melanoma represents the single best example of a human tumor that has been shown to elicit specific T-cell reactivity. The responsiveness of some patients with metastatic melanoma to treatment with the prototypic T-cell growth factor (TCGF), interleukin-2 (IL-2), indicates that T cells play a role in antitumor immunity. Interleukin-4 (IL-4), another TCGF that has been administered clinically to humans, was not associated with tumor response in our trials conducted at the Surgery Branch of the National Cancer Institute. Combination trials of IL-2 with IL-4 have shown no increase in responsiveness of melanoma or other tumors when compared to IL-2 alone. However, enhanced expansion of tumor-infiltrating lymphocytes (TILs) in vitro has been observed with combinations of low-dose IL-2 and IL-4. We have begun a study evaluating the trafficking of such expanded lymphocytes following their adoptive transfer in association with systemic administration of IL-2 and IL-4. We have established several TIL cultures from fresh tumor samples, maintained them in long-term culture, and marked them with the neomycin phosphotransferase gene using the LNL6 retroviral vector. Such TILs appear to demonstrate no notable alterations in phenotype or cytolytic activity when compared to their nontransduced counterparts. In addition to IL-2 and IL-4, there are a variety of other novel TCGFs that are now available for evaluation in preclinical and clinical trials. IL-7 induces proliferation and lymphokine-activated killer (LAK) cell activity from human peripheral blood mononuclear cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Modulation of myeloid proliferation and differentiation by monoclonal antibodies directed against a protein that interacts with the interleukin-3 receptor

Hematopoietic cells can be transformed through the acquisition of autocrine growth factor production. Because of their ability to inhibit autocrine growth, antibodies directed against the growth factor or its receptor may have therapeutic potential. However, these agents may also inhibit normal cell development. We have developed two monoclonal antibodies, 4G8 and 2F2, directed against a protein of 110 to 150 Kd that interacts with the interleukin-3 (IL-3) receptor (R) complex. These antibodies inhibit IL-3-induced proliferation of nonleukemic and leukemic IL-3-dependent cell lines, as well as the autonomous growth of WEHI-3B in vitro and in vivo. These results suggest the possibility that anti-IL-3R antibodies may be useful in the treatment of some leukemias. However, the effect of anti-IL-3R antibodies on normal myeloid development in vitro has not been examined. We examined the effect of 4G8 and 2F2 on the growth in vitro of colony-forming unit granulocyte-macrophage (CFU-GM) colonies induced by IL-3, granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage CSF (GM-CSF), and macrophage-CSF (M-CSF). Our results show that while 4G8 and 2F2 inhibited CFU-GM colony formation induced by IL-3, they augmented colony formation induced by the other hematopoietins. 4G8 and 2F2 also enhanced G-CSF-induced proliferation of 32Dc13 and GM-CSF-induced proliferation of PT18, confirming that the effect on CFU-GM was a direct effect. Finally, 4G8 and 2F2 inhibited G-CSF-induced differentiation of 32Dc13, similar to low levels of IL-3; yet, neither 4G8 nor 2F2 blocked binding of G-CSF to its receptor. These results indicate that, in the absence of IL-3 and in the presence of other hematopoietins, 4G8 and 2F2 can function as weak IL-3 agonists. These studies suggest that antibodies such as 4G8 and 2F2, directed against components of the IL-3R, could potentially augment myeloid growth in vivo, rather than inhibit myeloid growth.