A platform for rapid patient-derived cutaneous neurofibroma organoid establishment and screening.

Localized cutaneous neurofibromas (cNFs) are benign tumors that arise in the dermis of patients affected by neurofibromatosis type 1 syndrome. cNFs are benign lesions: they do not undergo malignant transformation or metastasize. Nevertheless, they can cover a significant proportion of the body, with some individuals developing hundreds to thousands of lesions. cNFs can cause pain, itching, and disfigurement resulting in substantial socio-emotional repercussions. Currently, surgery and laser desiccation are the sole treatment options but may result in scarring and potential regrowth from incomplete removal. To identify effective systemic therapies, we introduce an approach to establish and screen cNF organoids. We optimized conditions to support the ex vivo growth of genomically diverse cNFs. Patient-derived cNF organoids closely recapitulate cellular and molecular features of parental tumors as measured by immunohistopathology, methylation, RNA sequencing, and flow cytometry. Our cNF organoid platform enables rapid screening of hundreds of compounds in a patient- and tumor-specific manner.

Preclinical Efficacy of the Antibody-Drug Conjugate CLDN6-23-ADC for the Treatment of CLDN6-Positive Solid Tumors.

PURPOSE: Claudin-6 (CLDN6) is expressed at elevated levels in multiple human cancers including ovarian and endometrial malignancies, with little or no detectable expression in normal adult tissue. This expression profile makes CLDN6 an ideal target for development of a potential therapeutic antibody-drug conjugate (ADC). This study describes the generation and preclinical characterization of CLDN6-23-ADC, an ADC consisting of a humanized anti-CLDN6 monoclonal antibody coupled to monomethyl auristatin E (MMAE) via a cleavable linker. EXPERIMENTAL DESIGN: A fully humanized anti-CLDN6 antibody was conjugated to MMAE resulting in the potential therapeutic ADC, CLDN6-23-ADC. The antitumor efficacy of CLDN6-23-ADC was assessed for antitumor efficacy in CLDN6-positive (CLDN6+) and -negative (CLDN6-) xenografts and patient-derived xenograft (PDX) models of human cancers. RESULTS: CLDN6-23-ADC selectively binds to CLDN6, versus other CLDN family members, inhibits the proliferation of CLDN6+ cancer cells in vitro, and is rapidly internalized in CLDN6+ cells. Robust tumor regressions were observed in multiple CLDN6+ xenograft models and tumor inhibition led to markedly enhanced survival of CLDN6+ PDX tumors following treatment with CLDN6-23-ADC. IHC assessment of cancer tissue microarrays demonstrate elevated levels of CLDN6 in 29% of ovarian epithelial carcinomas. Approximately 45% of high-grade serous ovarian carcinomas and 11% of endometrial carcinomas are positive for the target. CONCLUSIONS: We report the development of a novel ADC, CLDN6-23-ADC, that selectively targets CLDN6, a potential onco-fetal-antigen which is highly expressed in ovarian and endometrial cancers. CLDN6-23-ADC exhibits robust tumor regressions in mouse models of human ovarian and endometrial cancers and is currently undergoing phase I study.

A simple high-throughput approach identifies actionable drug sensitivities in patient-derived tumor organoids.

Tumor organoids maintain cell-cell interactions, heterogeneity, microenvironment, and drug response of the sample they originate from. Thus, there is increasing interest in developing tumor organoid models for drug development and personalized medicine applications. Although organoids are in principle amenable to high-throughput screenings, progress has been hampered by technical constraints and extensive manipulations required by current methods. Here we introduce a miniaturized method that uses a simplified geometry by seeding cells around the rim of the wells (mini-rings). This allows high-throughput screenings in a format compatible with automation as shown using four patient-derived tumor organoids established from two ovarian and one peritoneal high-grade serous carcinomas and one carcinosarcoma of the ovary. Using our automated screening platform, we identified personalized responses by measuring viability, number, and size of organoids after exposure to 240 kinase inhibitors. Results are available within a week from surgery, a timeline compatible with therapeutic decision-making.

Current practices of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in the treatment of peritoneal surface malignancies: an international survey of oncologic surgeons.

BACKGROUND: The goal of the study was to investigate the current clinical practices among oncologic surgeons regarding cytoreductive surgery (CRS) with intraoperative hyperthermic intraperitoneal chemotherapy (HIPEC). METHODS: From September to October 2016, an online questionnaire surveyed the oncologic surgeons by email. The questionnaire included 20 multiple-choice questions of the following: eligibility for the CRS with HIPEC procedure, perioperative staging and surgery skill, assessment of residual tumors, and method used for intraperitoneal HIPEC. RESULTS: The response rate was 16% (34/217). The majority of respondents (68%) worked at a university hospital. All respondents indicated that mesenteric invasion is the most crucial factor affecting treatment decision. Most surgeons (79%) used the Sugarbaker's staging system to intraoperatively measure the extent of peritoneal invasion. The methods used to measure the extent of miliary pattern of residual tumor spread, and the amount of residual tumor after electrocauterization varied among the surgeons. Most responders (65%) used the closed system of HIPEC. CONCLUSIONS: Despite the fact that CRS HIPEC is the standard treatment for PSM, the clinical practices are very different according to each clinical situation. Nevertheless, mesenteric invasion was found to be the most important factor impacting the treatment decision-making by the majority of responders.

A TCR targeting the HLA-A*0201-restricted epitope of MAGE-A3 recognizes multiple epitopes of the MAGE-A antigen superfamily in several types of cancer.

Adoptive immunotherapy using TCR-engineered PBLs against melanocyte differentiation Ags mediates objective tumor regression but is associated with on-target toxicity. To avoid toxicity to normal tissues, we targeted cancer testis Ag (CTA) MAGE-A3, which is widely expressed in a range of epithelial malignancies but is not expressed in most normal tissues. To generate high-avidity TCRs against MAGE-A3, we employed a transgenic mouse model that expresses the human HLA-A*0201 molecule. Mice were immunized with two HLA-A*0201-restricted peptides of MAGE-A3: 112-120 (KVAELVHFL) or MAGE-A3: 271-279 (FLWGPRALV), and T cell clones were generated. MAGE-A3-specific TCR α- and ß-chains were isolated and cloned into a retroviral vector. Expression of both TCRs in human PBLs demonstrated Ag-specific reactivity against a range of melanoma and nonmelanoma tumor cells. The TCR against MAGE-A3: 112-120 was selected for further development based on superior reactivity against tumor target cells. Interestingly, peptide epitopes from MAGE-A3 and MAGE-A12 (and to a lesser extent, peptides from MAGE-A2 and MAGE-A6) were recognized by PBLs engineered to express this TCR. To further improve TCR function, single amino acid variants of the CDR3 α-chain were generated. Substitution of alanine to threonine at position 118 of the α-chain in the CDR3 region of the TCR improved its functional avidity in CD4 and CD8 cells. On the basis of these results, a clinical trial is planned in which patients bearing a variety of tumor histologies will receive autologous PBLs that have been transduced with this optimized anti-MAGE-A3 TCR.

Successful treatment of melanoma brain metastases with adoptive cell therapy.

PURPOSE: To determine the objective response rate and response duration of melanoma brain metastases to adoptive cell therapy (ACT) with autologous antitumor lymphocytes plus interleukin-2 following a lymphodepleting preparative regimen. METHODS: Between 2000 and 2009, 264 patients with metastatic melanoma received ACT, consisting of cyclophosphamide and fludarabine with or without total body irradiation, followed by the infusion of autologous tumor-infiltrating lymphocytes (TIL) or autologous peripheral blood lymphocytes retrovirally transduced to express a T-cell receptor (TCR) that recognized the melanocyte differentiation antigens gp-100 or MART-1. From this group, 26 patients were retrospectively identified to have had untreated brain metastases and extracranial disease before receiving ACT. The response rate and duration of melanoma brain metastases, as well as the overall response rate, response duration, and survival for these patients, are presented. RESULTS: Seventeen of these 26 patients received ACT with TIL. Seven of these patients (41%) achieved a complete response in the brain, and six patients achieved an overall partial response. In the nine patients that received TCR-transduced lymphocytes, two patients achieved a complete response in the brain (22%) and one of these two achieved an overall partial response. One patient developed a tumor-associated subarachnoid hemorrhage during the thrombocytopenic phase of therapy and had an uneventful metastatectomy. CONCLUSION: ACT with a nonmyeloablative preparative regimen using either TIL- or TCR gene-transduced cells and interleukin-2 can mediate complete and durable regression of melanoma brain metastases. This strategy can be used safely in selected patients with metastatic melanoma to the brain.

CD8+ enriched "young" tumor infiltrating lymphocytes can mediate regression of metastatic melanoma.

PURPOSE: Tumor-infiltrating lymphocytes (TIL) and interleukin (IL)-2 administered following lymphodepletion can cause the durable complete regression of bulky metastatic melanoma in patients refractory to approved treatments. However, the generation of a unique tumor-reactive TIL culture for each patient may be prohibitively difficult. We therefore investigated the clinical and immunologic impact of unscreened, CD8+ enriched "young" TIL. EXPERIMENTAL DESIGN: Methods were developed for generating TIL that minimized the time in culture and eliminated the individualized tumor-reactivity screening step. Thirty-three patients were treated with these CD8+ enriched young TIL and IL-2 following nonmyeloablative lymphodepletion (NMA). Twenty-three additional patients were treated with CD8+ enriched young TIL and IL-2 after lymphodepletion with NMA and 6 Gy of total body irradiation. RESULTS: Young TIL cultures for therapy were successfully established from 83% of 122 consecutive melanoma patients. Nineteen of 33 patients (58%) treated with CD8+ enriched young TIL and NMA had an objective response (Response Evaluation Criteria in Solid Tumors) including 3 complete responders. Eleven of 23 patients (48%) treated with TIL and 6 Gy total body irradiation had an objective response including 2 complete responders. At 1 month after TIL infusion the absolute CD8+ cell numbers in the periphery were highly correlated with response. CONCLUSIONS: This study shows that a rapid and simplified method can be used to reliably generate CD8+ enriched young TIL for administration as an individualized therapy for advanced melanoma, and may allow this potentially effective treatment to be applied at other institutions and to reach additional patients.

Phospholipase C gamma 1 is a physiological guanine nucleotide exchange factor for the nuclear GTPase PIKE.

Phospholipase C gamma 1 (PLC-gamma 1) hydrolyses phosphatidylinositol-4,5-bisphosphate to the second messengers inositol-1,4,5-trisphosphate and diacylglycerol. PLC-gamma 1 also has mitogenic activity upon growth-factor-dependent tyrosine phosphorylation; however, this activity is not dependent on the phospholipase activity of PLC-gamma 1, but requires an SH3 domain. Here, we demonstrate that PLC-gamma 1 acts as a guanine nucleotide exchange factor (GEF) for PIKE (phosphatidylinositol-3-OH kinase (PI(3)K) enhancer). PIKE is a nuclear GTPase that activates nuclear PI(3)K activity, and mediates the physiological activation by nerve growth factor (NGF) of nuclear PI(3)K activity. This enzymatic activity accounts for the mitogenic properties of PLC-gamma 1.