CXCL9/10-engineered dendritic cells promote T cell activation and enhance immune checkpoint blockade for lung cancer

Immune checkpoint blockade (ICB) with PD-1/PD-L1 inhibition has revolutionized the treatment of non-small cell lung cancer (NSCLC). Durable responses, however, are observed only in a subpopulation of patients. Defective antigen presentation and an immunosuppressive tumor microenvironment (TME) can lead to deficient T cell recruitment and ICB resistance. We evaluate intratumoral (IT) vaccination with CXCL9- and CXCL10-engineered dendritic cells (CXCL9/10-DC) as a strategy to overcome resistance. IT CXCL9/10-DC leads to enhanced T cell infiltration and activation in the TME and tumor inhibition in murine NSCLC models. The antitumor efficacy of IT CXCL9/10-DC is dependent on CD4+ and CD8+ T cells, as well as CXCR3-dependent T cell trafficking from the lymph node. IT CXCL9/10-DC, in combination with ICB, overcomes resistance and establishes systemic tumor-specific immunity in murine models. These studies provide a mechanistic understanding of CXCL9/10-DC-mediated host immune activation and support clinical translation of IT CXCL9/10-DC to augment ICB efficacy in NSCLC.

Dendritic Cell Vaccination in Non-Small Cell Lung Cancer: Remodeling the Tumor Immune Microenvironment

Non-small-cell lung cancer (NSCLC) remains one of the leading causes of death worldwide. While NSCLCs possess antigens that can potentially elicit T cell responses, defective tumor antigen presentation and T cell activation hinder host anti-tumor immune responses. The NSCLC tumor microenvironment (TME) is composed of cellular and soluble mediators that can promote or combat tumor growth. The composition of the TME plays a critical role in promoting tumorigenesis and dictating anti-tumor immune responses to immunotherapy. Dendritic cells (DCs) are critical immune cells that activate anti-tumor T cell responses and sustain effector responses. DC vaccination is a promising cellular immunotherapy that has the potential to facilitate anti-tumor immune responses and transform the composition of the NSCLC TME via tumor antigen presentation and cell-cell communication. Here, we will review the features of the NSCLC TME with an emphasis on the immune cell phenotypes that directly interact with DCs. Additionally, we will summarize the major preclinical and clinical approaches for DC vaccine generation and examine how effective DC vaccination can transform the NSCLC TME toward a state of sustained anti-tumor immune signaling.

CCL21-DC in situ vaccination in murine NSCLC overcomes resistance to immunotherapy and generates systemic tumor-specific immunity

BACKGROUND

Despite recent advances in immunotherapy, many patients with non-small cell lung cancer (NSCLC) do not respond to immune checkpoint inhibitors (ICI). Resistance to ICI may be driven by suboptimal priming of antitumor T lymphocytes due to poor antigen presentation as well as their exclusion and impairment by the immunosuppressive tumor microenvironment (TME). In a recent phase I trial in patients with NSCLC, in situ vaccination (ISV) with dendritic cells engineered to secrete CCL21 (CCL21-DC), a chemokine that facilitates the recruitment of T cells and DC, promoted T lymphocyte tumor infiltration and PD-L1 upregulation.

METHODS

Murine models of NSCLC with distinct driver mutations (KrasG12D/P53+/-/Lkb1-/- (KPL); KrasG12D/P53+/- (KP); and KrasG12D (K)) and varying tumor mutational burden were used to evaluate the efficacy of combination therapy with CCL21-DC ISV plus ICI. Comprehensive analyses of longitudinal preclinical samples by flow cytometry, single cell RNA-sequencing (scRNA-seq) and whole-exome sequencing were performed to assess mechanisms of combination therapy.

RESULTS

ISV with CCL21-DC sensitized immune-resistant murine NSCLCs to ICI and led to the establishment of tumor-specific immune memory. Immunophenotyping revealed that CCL21-DC obliterated tumor-promoting neutrophils, promoted sustained infiltration of CD8 cytolytic and CD4 Th1 lymphocytes and enriched progenitor T cells in the TME. Addition of ICI to CCL21-DC further enhanced the expansion and effector function of T cells both locally and systemically. Longitudinal evaluation of tumor mutation profiles revealed that CCL21-DC plus ICI induced immunoediting of tumor subclones, consistent with the broadening of tumor-specific T cell responses.

CONCLUSIONS

CCL21-DC ISV synergizes with anti-PD-1 to eradicate murine NSCLC. Our data support the clinical application of CCL21-DC ISV in combination with checkpoint inhibition for patients with NSCLC.

Abstract 4206: In situ vaccination with CCL21-DC sensitizes non-responsive murine NSCLCs to anti-PD-1 therapy and generates systemic tumor-specific immune memory

Decresased responses to immune checkpoint inhibitors (ICIs) in NSCLC are associated with low tumor mutational burden (TMB), impaired tumor antigen presentation, decreased baseline CD8+ T lymphocytes tumor infiltration and low PD-L1 expression in the tumor microenvironment (TME). One approach to augment the efficacy of ICIs in NSCLC is to enhance anti-tumor T cell responses by utilizing in situ vaccination (ISV) with professional antigen-presenting dendritic cells (DCs). In preclinical studies as well as a phase I clinical trial, we have shown that ISV with gene-modified DCs expressing CCL21 (CCL21-DC) promotes effector T lymphocyte infiltration into the tumor, PD-L1 upregulation, and systemic tumor-specific immune responses. We hypothesized that in situ vaccination with CCL21-DC could promote T cell priming and activation, thereby sensitizing non-responsive NSCLC tumors to ICI. Utilizing multiple syngeneic murine models of NSCLC with distinct driver mutations [KrasG12D/P53+/-/Lkb1-/- (KPL); KrasG12D/P53+/- (KP); and KrasG12D (K)] and varying TMB, we observed that CCL21-DC ISV synergizes with anti-PD-1 therapy resulting in the eradication of a subset of tumors. Evaluation of KPL tumors by flow cytometry and scRNA-seq revealed that combination therapy reprogrammed the myeloid compartment to be less immunosuppressive, and induced T cell infiltration, Th1 polarization, as well as the enrichment of stem-like TCF1+ T cells within the TME. Intratumoral (IT) CCL21-DC enhanced CD103+DC migration to the local lymph node as determined by flow cytometry. Addition of ICI to IT CCL21-DC resulted in enhanced T cell proliferation and INF-γ secretion within the TME and the spleen. Whole exome sequencing (WES) of tumors revealed immunoediting of tumor subclones after IT CCL21-DC and ICI combination therapy. Tumor rechallenge studies demonstrated the establishment of systemic tumor-specific immunity in a subset of mice that were cured of disease.In conclusion, tumor vaccination with CCL21-DC sensitizes immune-resistant murine NSCLC to anti-PD-1 therapy. Combination therapy enhances anti-tumor T cell responses, resulting in immunoediting of tumor subclones and the generation of systemic tumor-specific immunity. In an ongoing clinical trial, we are evaluating the safety and efficacy of ISV with CCL21-DC in combination with anti-PD-1, pembrolizumab, in patients with advanced NSCLC who have progressed on front-line therapy.

Citation Format: Ramin Salehi-Rad, Raymond J. Lim, Linh M. Tran, Yushen Du, Camelia Dumitras, Tianhao Zhang, William Crosson, Jensen Abascal, Kostyantyn Krysan, Bin Liu, Steven M. Dubinett. In situ vaccination with CCL21-DC sensitizes non-responsive murine NSCLCs to anti-PD-1 therapy and generates systemic tumor-specific immune memory [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4206.

Inhibition of Granulocytic Myeloid-Derived Suppressor Cells Overcomes Resistance to Immune Checkpoint Inhibition in LKB1-Deficient Non-Small Cell Lung Cancer

LKB1 inactivating mutations are commonly observed in patients with KRAS-mutant non-small cell lung cancer (NSCLC). Although treatment of NSCLC with immune checkpoint inhibitors (ICI) has resulted in improved overall survival in a subset of patients, studies have revealed that co-occurring KRAS/LKB1 mutations drive primary resistance to ICIs in NSCLC. Effective therapeutic options that overcome ICI resistance in LKB1-mutant NSCLC are limited. Here, we report that loss of LKB1 results in increased secretion of the C-X-C motif (CXC) chemokines with an NH2-terminal Glu-Leu-Arg (ELR) motif in premalignant and cancerous cells, as well as in genetically engineered murine models (GEMM) of NSCLC. Heightened levels of ELR⁺ CXC chemokines in LKB1-deficient murine models of NSCLC positively correlated with increased abundance of granulocytic myeloid-derived suppressor cells (G-MDSC) locally within the tumor microenvironment and systemically in peripheral blood and spleen. Depletion of G-MDSCs with antibody or functional inhibition via all-trans-retinoic acid (ATRA) led to enhanced antitumor T-cell responses and sensitized LKB1-deficent murine tumors to PD-1 blockade. Combination therapy with anti-PD-1 and ATRA improved local and systemic T-cell proliferation and generated tumor-specific immunity. Our findings implicate ELR⁺ CXC chemokine-mediated enrichment of G-MDSCs as a potential mediator of immunosuppression in LKB1-deficient NSCLC and provide a rationale for using ATRA in combination with anti-PD-1 therapy in patients with LKB1-deficient NSCLC refractory to ICIs. SIGNIFICANCE: These findings show that accumulation of myeloid-derived suppressor cells in LKB1-deficient non-small cell lung cancer can be overcome via treatment with all-trans-retinoic acid, sensitizing tumors to immunotherapy.

Clinical outcome of cotransplantation of peripheral nerve and adrenal medulla in patients with Parkinson's disease. Clínica Puerta de Hierro Neural Transplantation Group

OBJECT

Transplants of adrenal medulla (AM) and fetal ventral mesencephalon (FVM) are currently being tested as therapeutic alternatives in patients with Parkinson's disease (PD). At the Clínica Puerta de Hierro in Madrid, a controlled clinical trial is underway to establish which donor tissue, if any, is the best for open surgical implantation in patients with PD.

METHODS

Since 1987, varying degrees of clinical improvement have been achieved in Grade IV and V parkinsonian patients by implanting perfused AM and FVM into the right caudate nucleus. To investigate further whether implantation of different types of donor tissues results in qualitatively and quantitatively different degrees of recovery, four patients with Grade IV or V PD received implants of pre-coincubated autologous AM and intercostal nerve in the caudate nucleus. Four nonsurgically treated patients served as a control group. Three years posttransplantation, longer on phases (46.2%+/-10.4% of the day presurgery to 87.5%+/-10.4% of the day 36 months postsurgery) and improved symptoms in on and off phases persist in all four cases, with reduced dyskinesias (67.1%+/-9.2% of the day in on phases presurgery to 17%+/-13.8% of the day in on phases 36 months postsurgery). Progress appears to be stepwise, starting within weeks of tranplantation and becoming clinically significant in the 2nd and 3rd months (similar to our AM- and sooner than in our FVM-implanted patients), followed by a period of stability and, after a second wave of improvement 12 to 18 months posttransplantation (similar to FVM implants), has continued (87.5+/-7 points presurgery to 46+/-5.6 points 36 months postsurgery). In the experimental group, doses of levodopa have been reduced by more than 60% and dopamine agonist use has not resumed. In contrast, there have been no significant clinical changes in the control group.

CONCLUSIONS

Implantation of tissue other than fetal tissue can promote a long-term improvement in the clinical symptomatology of seriously disabled parkinsonian patients. This finding is supported by the autopsy report of a patient with PD who had undergone grafting of AM plus peripheral nerve in which it was demonstrated that a large number of tyrosine hydroxylase-positive cells survive 1 year after implantation. In addition, there was a dense network of host dopaminergic fibers around the graft.

Clinical experience with cotransplantation of peripheral nerve and adrenal medulla in patients with Parkinson's disease

Coimplants of adrenal medulla (AM) and peripheral nerve (PN) in animal models of Parkinson's disease (PD) have shown that AM cells survive longer, tend to show neuronal phenotype, and enhance sprouting of host fibers. Since 1987, our implants of perfused AM and fetal ventral mesencephalon (FVM) in PD patients have achieved varying degrees of clinical improvement. If the donor tissue determines the improvement, different types of implants should result in qualitatively and quantitatively different degrees of improvement. The purpose of this study is to determine whether or not the clinical course, improvement slope, and reduction of medication observed in PD patients who undergo tissue transplantation (Tx) depend on the donor tissue type. In a pilot study, four grade IV-V PD patients received implants of precoincubated autologous AM and intercostal nerve in the caudate nucleus (open surgery). Clinical assessment was based on international scales (UPD) as reported for Tx of FVM and perfused AM. There were no systemic or neurologic complications. Four years post-Tx, longer On phases and improved PD symptoms (ADL and motor-UPD) in On and Off persist in four cases, with reduced dyskinesias. Progress appears to be stepwise, starting within weeks of Tx (similar to AM and sooner than our FVM implants), followed by a period of stability and, after a second wave of improvement 12-18 months post-Tx (similar to FVM implants), continues to date. L-dopa medication has been reduced by more than 60% and dopamine agonist use has not resumed. We conclude that our recipients continue to be clinically better than prior to Tx. The course of recovery after co-Tx of AM and PN differs from that of FVM or AM implants. This fact may be related to the etiological factors that produce the improvement.

Grafting of perfused adrenal medullary tissue into the caudate nucleus of patients with Parkinson's disease. Clinica Puerta de Hierro Neural Transplantation Group

The authors report results obtained in 20 severely affected patients with Parkinson's disease (Grade IV or V) who received an autotransplant of perfused adrenal medullary tissue. This study seems to indicate that these autoimplants can improve the parkinsonian symptomatology and induce amelioration in the patients' performance of routine activities. All the symptoms analyzed showed improvement, although it differed in intensity and time of onset. Moreover, this improvement was accompanied by a reduction in the daily intake of L-dopa, with discontinuance of dopamine agonists and amantadine. A number of medical complications were encountered, including three deaths, probably related to performing abdominal surgery in seriously affected parkinsonian patients who were unable to tolerate the discontinuance of their medication. The transient psychiatric disorders observed appeared to be related to the postoperative dose of L-dopa and/or anticholinergic agents administered, and diminished or disappeared when the doses were reduced. The reasons for improvement, which was bilateral, remain unknown, although one cause may be the surgical trauma (minicaudotomy) together with the implantation of adrenal medullary tissue, which may promote the sprouting of surviving dopaminergic fibers. Moreover, in this series, perfusion of adrenal medulla increased the capacity for revascularization of the tissue and may have reduced the damaging effects of warm ischemia on the cells. This, together with the existence of fenestrated vessels, could hypothetically have served as an access point for drugs, and if the implanted cells were viable, they might have served to store and manufacture different factors and/or transmitters. These results as well as those of other groups justify the development of a controlled international clinical trial.

Preparation of adrenal medullary tissue for transplantation in Parkinson's disease: a new procedure. Technical note

The authors describe a technique by which adrenal medullary tissue can be easily dissected from the adrenal cortex. The method involves perfusion with Locke's modified buffer, dissection of adrenal gland in buffer free of calcium or magnesium, and storage in a culture medium before implantation into the caudate nucleus of patients with Parkinson's disease. This method seems to increase the viability and purity of adrenal medullary tissue. The results obtained in 15 parkinsonian patients implanted with perfused adrenal medulla indicate the potential value of this technique.

Atypical hepatic tuberculosis presenting as obstructive jaundice

A 78-yr-old female with a short history of malaise, anorexia, mild pyrexia, and obstructive jaundice is presented. A diagnosis of tuberculosis of the liver and gallbladder was established at laparotomy. In spite of anti-tuberculous therapy, the patient died on the 5th postoperative day. Widespread miliary tuberculosis affecting the lung, kidneys, spleen, and mesenteric lymph nodes was observed in postmortem studies, with strikingly severe involvement of the intrahepatic bile ducts. Saccular dilatation of the bile ducts alternating with areas of stenosis and narrowed intrahepatic bile ducts was seen. A correlation of the radiological and hepatic postmortem findings is discussed. The atypical presentation of tuberculosis in present times and the causes of jaundice in atypical cases of hepatic tuberculosis are discussed. The rarity of gallbladder tuberculosis is pointed out.

Another test of the effect of group composition on member behavior change

Three-person groups (N = 24) dedicated to addressing assertion deficits common to their (female) members were so composed that one member (a confederate) consistently enacted one of four prescribed conditions: (1) personal warmth/success in changing; (2) personal warmth/failure to change; (3) lack of warmth/success in changing; and (4) lack of warmth/failure to change. Both confederate warmth and success modeling influenced the level of assertion change behavior reported by group members. These results confirm propositions based on clinical observations that therapeutic groups benefit measurably by the presence of one or more "warmth generators" and "success models." The results also suggest that while group members are influenced to effect change by success modeling, they tend to attribute this influence to confederate warmth. In addition, they tend to attribute success in changing to warm persons and failure to change to persons who are lacking in warmth.

Alleviation of diabetic microangiopathy in rats by pancreatic islet cell transplantation

Diabetes was induced in female WAG rats by an injection of streptozotocin. The resultant diabetic microangiopathy was studied in the kidney and other organs and the effectiveness of pancreatic islet cell transplantation in preventing and reversing the microvascular complications was assessed. It was found that intraportal transplants of more than 1000 islets produced metabolic normality in most animals and successful transplants prevented the development of diabetic microangiopathy. Very early lesions could be completely restored to normal. The findings strongly support the necessity of good metabolic control of human diabetic patients to prevent microangiopathic damage.

Liver tumours following streptozotocin administration in rats and the effects of pancreatic islet cell transplantation

The effects of a single injection of streptozotocin, at a dosage of 50 mg/kg body weight, have been studied in female inbred WAG rats. The resultant diabetes in the streptozotocin treated animals was treated in one group of animals by an intraportal pancreatic islet cell transplantation whilst another group received no transplant or insulin treatment. The incidence of tumours were determined at autopsy in animals sacrificed at regular intervals. Tumours, apart from one renal adenocarcinoma, were seen only in the liver and only in streptozotocin treated animals. Liver nodules and cysts were most common in animals which had received both streptozotocin and an islet cell transplant.

Feminizing adrenocortical carcinoma in a postmenopausal woman

The successful surgical removal of a feminizing adrenal tumour in a postmenopausal woman is described. Most of these tumours are malignant and the pathological findings and the biological behaviour of the tumour frequently do not correlate, so that a careful follow-up is necessary. In the presence of vaginal bleeding in a postmenopausal woman endometrial carcinoma should be considered. If this has been ruled out and if oestrogens are elevated with low plasma gonadotrophins, a feminizing ovarian or adrenal tumour should be considered.

Adrenal cysts: diagnostic value of "intravenous viscerogram"

Two cases of adrenal pseudocysts are presented, one secondary to the necrosis of an adenoma and the other a hemorrhagic pseudocyst. The diagnosis of these tumors is usually made radiologically owing to the vagueness of symptoms and nonexistent specific laboratory examinations, so that preoperative diagnosis is uncommon. We present a radiologic technique, intravenous viscerogram, which may be useful in the diagnosis of adrenal cysts. This procedure is easy to carry out and has almost no complications for the patient. The classification, clinical findings, and surgical treatment of adrenal cysts are discussed.