Molecular Cancer Therapeutics最新文献

Melanoma is an aggressive cancer in dogs involving skin and mucosa similar to humans. Anchored immunotherapeutics offer a novel approach to increase intratumoral retention of therapeutic payloads while decreasing systemic exposure, and this strategy can be critically evaluated through a comparative oncology approach. JEN-101 is an anchored canine IL-12 tethered to aluminum hydroxide administered by local injection. A phase I study was conducted to determine the tolerability, activity, and immune responses of JEN-101 in dogs with advanced melanoma. A 3 + 3 dose-escalation design was used to evaluate intratumoral injection of JEN-101 at 1, 3, 10, or 20 μg/kg every 3 weeks for four cycles. A second course was allowable in the absence of disease progression or toxicity. Peripheral blood, serum, and tumor biopsies were collected at baseline and at prespecified timepoints for pharmacokinetic and immune analyses, which included serum cytokine assay, IHC, and gene expression assessment. JEN-101 was well tolerated with adverse events being fever, lethargy, and isolated elevated liver enzymes. Five dogs experienced grade 3 events, and no grade 4 events were observed. Pharmacokinetic analysis showed a trend toward dose-related maximum serum concentration within 8 hours of injection. Responding dogs demonstrated increased systemic IFN-γ and IL-10 AUC levels and local recruitment of CD3+ T cells. Increased proinflammatory and antigen-processing gene expression was identified in responding lesions. JEN-101 was well tolerated with evidence of biological and therapeutic activities. Anchored IL-12 immunotherapy merits further investigation in dogs with melanoma, and our approach represents an immunocompetent model to inform human clinical trials.

Radiation-induced fibrosis (RIF) is a progressive pathology deleteriously impacting cancer survivorship. CXCL12 is an immune-stromal signal implicated in fibrosis and innate response. We hypothesized that modulation of CXCL12 would phenotypically mitigate RIF. CXCL12 expression was characterized in a rodent model of RIF and its expression modulated by the intravascular delivery of lentiviral vectors encoding small hairpin RNA to silence (LVShCXCL12) or overexpress (LVOeCXCL12) CXCL12. Multimodal fibrotic outcomes were quantified, and flow cytometry and Y-chromosome lineage-tracking studies performed to examine cellular recruitment and activation after radiotherapy. Whole-tissue RNA sequencing was used to examine matrisomal response. MATBIII tumors were engrafted within tissues with differing levels of CXCL12 expression, and tumoral response to RT was evaluated. CXCL12 was upregulated in irradiated fibroblasts demonstrating DNA damage after radiotherapy, which led to the recruitment of CD68+ macrophages. Silencing CXCL12 with LVShCXCL12 demonstrated reduced RIF phenotype as a result of decreased macrophage recruitment. Transcriptomic profiling identified osteopontin (OPN; SPP1) as being highly differentially expressed in LVShCXCL12-treated tissues. Tumors growing in tissues devoid of CXCL12 expression responded better after RT because of reductions in peritumoral fibrosis as a result of decreased CXCL12 and OPN expression at the tumor/normal tissue interface. This was also associated with greater CD8+ T-cell infiltration in tumors with less fibrosis. Antibody-mediated OPN blockade slowed tumor growth by increased intratumoral CD8+ T-cell activation. The CXCL12/OPN axis is an important node of immune/matrisomal cross-talk in the development of fibrosis. Therapeutic manipulation of this axis may offer greater antitumor efficacy while also reducing adverse effects.

Glioblastoma (GBM) is the most frequent malignant brain tumor. We recently discovered that oncolytic herpes simplex virus engineered to disable tumor-intrinsic protein kinase R (PKR) signaling (oHSV-shPKR) could increase oHSV oncolysis and antitumor immune response. However, in this study, we show that disabling tumor-intrinsic PKR signaling can also induce the activation of the indoleamine 2,3-dioxygenase (IDO) signaling pathway. Both GBM tumor progression and oHSV intratumoral therapy increased infiltration of IDO+CD11c+ dendritic cells (DC) into the tumor. The coculture of oHSV-infected human GBM neurospheres with monocyte-derived DCs (MoDC) dramatically increased IDO signaling activation in MoDCs through type-I IFN signaling. Addition of IDO inhibitor (indoximod) in the coculture significantly increased MoDC activation and reduced the consumption of tryptophan. Combining indoximod and oHSV significantly inhibited tumor growth and induced antigen-specific CD8+ T-cell activation. These results suggest that inhibition of the IDO pathway could significantly block feedback immunosuppression during oncolytic virotherapy of GBM.

Various combination therapies have been investigated to overcome the limitations of using immune checkpoint inhibitors. However, determining the optimal combination therapy remains challenging. To overcome the therapeutic limitation, we conducted a translational research to elucidate the mechanisms by which AXL inhibition enhances antitumor effects when combined with anti-PD-1 antibody therapy. Herein, we demonstrated improved antitumor effects through combination treatment with denfivontinib and pembrolizumab which resulted in enhanced differentiation into effector CD4+ and CD8+ memory T cells, accompanied by an increase in IFN-γ expression in the YHIM-2004 xenograft model derived from patients with non-small cell lung cancer. Concurrently, a reduction in the number of immunosuppressive M2 macrophages and myeloid-derived suppressor cells was observed. Mechanistically, denfivontinib potentiated the NOD-like receptor pathway, thereby facilitating NLRP3 inflammasome formation. This leads to macrophage activation via NF-κB signaling pathway activation. We have confirmed that the positive interaction between macrophages and T cells arises from the enhanced antigen-presenting machinery of activated macrophages. Furthermore, the observed tumor effects in AXL knockout mice confirmed that AXL inhibition by denfivontinib enhances the antitumor effects, thus opening new avenues for therapeutic interventions aimed at overcoming limitations in immunotherapy. To demonstrate the extent to which our findings reflect clinical results, we analyzed bulk RNA sequencing data from 21 patients with non-small cell lung cancer undergoing anti-PD-1 immunotherapy. The NLRP3 inflammasome score influenced enhanced immune responses in patient data undergoing anti-PD-1 immunotherapy, suggesting a role for the NLRP3 inflammasome in activating immune responses during treatment.

Primary activating mutations in KIT (exons 9/11) are key driver alterations in about 80% of gastrointestinal stromal tumors (GIST). Imatinib, a small molecule tyrosine kinase inhibitor, is used successfully as first-line therapy for unresectable metastatic or recurrent GIST patients, but secondary resistance mutations in the KIT kinase domains frequently occur. Currently approved later-line therapies target these mutations incompletely with limited clinical benefit. M4205, a kinome-selective KIT inhibitor, was designed to address this high unmet medical need by inhibiting all relevant KIT driver and resistance mutations. Compared to imatinib, M4205 shows stronger antitumor activity in preclinical GIST models driven by oncogenic KIT driver mutations. M4205 demonstrates clinically relevant efficacy in a range of preclinical GIST models expressing different secondary KIT resistance mutations. The kinase selectivity profile of M4205 is superior to registered standard of care and investigational agents. M4205, now IDRX-42, is currently being investigated in a Phase 1 first-in-human study in participants with GIST.

Prostate cancer is considered immunologically "cold", with low mutational burden, tumor-infiltrating immune cells, and PD-L1 levels, culminating in poor response to immune checkpoint therapies. Bispecific CD3 redirection antibodies can elicit T cell-mediated cytotoxicity and hold promise for immune cell recruitment into prostate tumors. CD3 redirection antibodies in solid tumors are still in early phases of clinical development, and it is not yet understood whether these potential therapies will achieve the high response rates observed in hematological malignancies or result in durable T cell responses. Here we demonstrated that treatment with a PSMA targeted CD3 redirector resulted in efficacy against LnCaP.AR human prostate xenografts in CD34+ cord blood humanized mice. Efficacy correlated with T cell infiltration into tumors with an activated phenotype, but also increased PD-L1 expression. Engineered overexpression of PD-L1 in LNCaP.AR tumors resulted in resistance to PSMAxCD3 bispecific antibody treatment, whereas sensitivity was restored in combination with anti-PD-1 antibody pembrolizumab. PSMAxCD3 and anti-PD-1 combination treatment resulted in complete tumor responses in approximately 20% of mice, and elicited immune responses that delayed growth of rechallenged tumors. In a second prostate model, patient derived LuCaP 86.2 xenografts, PSMAxCD3 monotherapy treatment resulted in complete responses in 25% of mice. When PSMAxCD3-treated responder mice were rechallenged with LuCaP 86.2 tumors, partial control of tumor regrowth was associated with expansion of effector memory T cells. These studies show that PSMAxCD3 treatment elicits antitumor memory T cell responses, and that combination with PD-1 blockade can enhance these effects in tumors with immune suppressive tumor microenvironments.

Anaplastic thyroid cancer (ATC) is a rare but severe form of thyroid cancer responsible for approximately 50% of thyroid cancer deaths. Consequently, the identification of innovative therapies remains crucial for the effective treatment of ATC. Molecular radiotherapy is a rapidly growing field within oncology and the cell surface antigen CD44v6, which is overexpressed in several cancers, is a plausible target for molecular radiotherapy of ATC. Immunohistochemistry (IHC) of 39 ATC patient samples were evaluated for CD44v6 expression. Biodistribution and dosimetry of 125I/177Lu-labeled UU-40, a CD44v6 specific antibody, followed by in vivo efficacy in two ATC xenograft models with varying target expression levels (ACT-1 and BHT-101) accompanied by SPECT-imaging evaluated radiolabeled UU-40 for therapeutic efficiency in ATC xenografts. The IHC revealed CD44v6 immunoreactivity in 46% of ATC patient samples. The biodistribution favored 177LuUU-40 over the 125I-labeled antibody and confirmed in vivo specificity of both radioconjugates. The in vivo efficacy and accompanied SPECT imaging of a moderate CD44v6-expressing xenograft model (BHT-101) verified the tumor specificity as well as the target-specific effect of 177Lu -UU-40 on tumor growth and survival. A 100% complete response rate was demonstrated as a result of therapy using a single dose of 16 MBq 177Lu -UU-40 in a high CD44v6-expressing xenograft model (ACT-1), and SPECT-imaging revealed excellent tumor uptake of the radioconjugate at 14 days post-injection. This study verifies the expression of CD44v6 in ATC and cements the superiority and promise of 177Lu -UU-40 over 131I-UU-40 for antibody-based molecular radiotherapy of CD44v6-positive ATC.

Increased PI3K signaling as a result of PIK3CA mutation or amplification or decreased expression of PTEN (phosphatase and tensin homolog deleted on chromosome 10) is one of the most common alterations in head and neck squamous cell carcinoma (HNSCC). PTEN negatively regulates PI3K signaling and its downstream effectors including COX2. COX2 mediates the synthesis of PGE2 which contributes to immunosuppression in the tumor microenvironment. PGE2 also binds to one or more EP receptors (EP1-EP4) and promotes the growth of tumor cells via activation of EP2 and EP4. However, the role of PGE2 in PTEN-deficient HNSCC is incompletely understood. Here, we assessed PGE2 signaling in PTEN-deficient HNSCC and evaluated the effect of aspirin or TPST-1495, a dual EP2/EP4 antagonist, on the growth of PTEN knockout (KO) and PIK3CA-altered HNSCC tumors in immunocompetent mice. Our results demonstrated that aspirin selectively inhibits the growth of PTEN KO HNSCC tumors. TPST-1495 inhibited tumor growth and substantially increased the anti-tumor activity of the immune checkpoint inhibitor anti-PD1. To date, there are no FDA-approved therapies for PI3K pathway-altered HNSCC. Our findings suggest that NSAIDs demonstrate anti-tumor activity in PTEN-deficient or PI3K-altered tumors whereas EP2/EP4 targeting may augment FDA-approved anti-PD1 therapy in HNSCC.

Radiopharmaceutical therapy (RPT) is a promising approach to treating solid tumors, but therapeutic advances are impeded by the lack of broadly expressed targets and shared molecular vulnerability across different tumor types. We evaluate VLA-4 (integrin α4β1) as a potential target for RPT in solid tumors using radiolabeled copper-64 ([64Cu]Cu-) and copper-67 ([67Cu]Cu-CB-TE1A1P-PEG4-LLP2A) LLP2A, a peptidomimetic ligand of VLA-4, for preclinical imaging and RPT testing. Expression analysis of ITGA4, encoding the alpha 4 subunit of VLA-4, revealed overexpression in hematological malignancies and various solid tumors compared to healthy tissue. Flow cytometry showed medium to high VLA-4 expression in 77% of tested cancer cell lines. PET/CT imaging with [64Cu]Cu-LLP2A demonstrated tracer uptake in tumors and lymphoid tissues. In toxicity studies, [67Cu]Cu-LLP2A administered at 37-74 MBq was well-tolerated, causing only thymic atrophy without long-term hematological or tissue toxicity. Tumor dose response was observed in B16-F10 melanoma models. Using orthotopic syngeneic models (B16-F10, B78, 4T1, GL261, TH-MYCN, and E2A-PBX1) and human cancer models (SK-MEL-37, 143B, and IMR-5), we conducted PET/CT imaging and biodistribution studies, with selected models used for [64Cu]Cu-LLP2A dosimetry calculations. Given VLA-4's broad expression across cancer tissues, demonstrated on-target effects, acceptable toxicity profile, and favorable dosimetry in preclinical models, further investigation of [67Cu]Cu-LLP2A as an RPT agent is warranted.

Mutations in the tyrosine kinase domain of the Anaplastic Lymphoma Kinase (ALK) oncogene in neuroblastoma occur most frequently at one of three hotspot amino acid residues, with the F1174* and F1245* variants conferring de novo resistance to first and second generation ALK inhibitors including crizotinib and ceritinib. Lorlatinib, a third generation ALK/ROS inhibitor, overcomes de novo resistance and induces complete and sustained tumor regressions in patient-derived xenograft (PDX) models unresponsive to crizotinib. Lorlatinib has now completed Phase 1 testing in children and adults with relapsed/refractory ALK-driven neuroblastoma and entered pivotal Phase 3 testing within the Children's Oncology Group. To define mechanisms underlying the superior activity of lorlatinib, we utilized a chemical proteomics approach to quantitatively measure functional kinome dynamics in response to lorlatinib and crizotinib in clinically relevant ALK-driven neuroblastoma PDX models. Lorlatinib was a markedly more potent inhibitor of ALK and preferentially downregulated several kinases implicated in G2/M cell cycle transition compared to crizotinib. Lorlatinib treatment also led to the repression of MYCN expression and its occupancy at promoters of the same G2/M kinases. These data providing mechanistic insight into the superior efficacy of lorlatinib over crizotinib for the treatment of ALK-driven neuroblastoma.