Biology subjects

Laakkonen, P.

Publications and source records attributed to Laakkonen, P..

8 recordsLinked to original sources

bioRxiv2025

Therapeutic Eradication of Cancer-associated Fibroblasts Inhibits in vivo progression of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) remains a lethal disease with an unmet medical need. therapeutic elimination of cancer associated fibroblasts (CAFs), key drivers of tumor aggressiveness, has been the focus of recent studies. However, the inherent heterogeneity and plasticity of CAFs have hampered the development of CAF-targeted therapies. Clemastine, an FDA-approved cationic amphiphilic drug, is known to elicit cytotoxic lysosomal membrane permeabilization in solid tumors. We evaluated its efficacy in patient derived PDAC organoids and patient avatars. In vitro, half of the organoids responded to clemastine, although sensitivity did not predict in vivo outcomes. In vivo, clemastine treatment led to CAF depletion, halted cancer progression and delayed disease progression. To assess potential synergy with standard-of-care therapy, clemastine was combined with gemcitabine. The combination enabled dual targeting--clemastine effectively eliminated all CAF subtypes, while gemcitabine eradicated cancer cells - leading to inhibition of metastatic dissemination. These findings support clemastine as a promising companion therapy in PDAC, targeting the tumor-supportive microenvironment.

cancer biology↗

bioRxiv2022

Efficacy and safety of glycosphingolipid SSEA-4 targeting CAR-T cells in solid tumors

Chimeric antigen receptor (CAR) T-cell immunotherapies for solid tumors face critical challenges such as heterogeneous antigen expression. We characterized SSEA-4 cell-surface glycolipid as a target for CAR-T cell therapy. SSEA-4 is mainly expressed during embryogenesis but is also found in several cancer types making it an attractive tumor-associated antigen. Anti-SSEA-4 CAR-T cells were generated and assessed pre-clinically in vitro and in vivo for anti-tumor response and safety. SSEA-4 CAR-T cells effectively eliminated SSEA-4 positive cells in all tested cancer cell lines whereas SSEA-4 negative cells lines were not targeted. In vivo efficacy and safety studies using NSG mice and the high-grade serous ovarian cancer cell line OVCAR4 demonstrated a remarkable and specific anti-tumor response at all CAR-T cell doses used. At high T cell doses, CAR-T cell-treated mice showed signs of health deterioration after a follow-up period. However, severity of toxicity was reduced with delayed onset when lower CAR-T cell doses were used. Our data demonstrate the efficacy of anti-SSEA-4 CAR-T therapy; however, safety strategies, such as dose-limiting and/or equipping CAR-T cells with combinatorial antigen recognition should be implemented for its potential clinical translation.

cancer biology↗

bioRxiv2022

KSHV infection of endothelial precursor cells with lymphatic characteristics as a novel model for translational Kaposis sarcoma studies

Kaposis sarcoma herpesvirus (KSHV) is the etiologic agent of Kaposis sarcoma (KS), a hyperplasia consisting of enlarged malformed vasculature and spindle-shaped cells, the main proliferative component of KS. While spindle cells express markers of lymphatic and blood endothelium, the origin of spindle cells is unknown. Endothelial precursor cells have been proposed as the source of spindle cells. We previously identified two types of circulating endothelial colony forming cells (ECFCs), ones that expressed markers of blood endothelium and ones that expressed markers of lymphatic endothelium. Here we examined both blood and lymphatic ECFCs infected with KSHV. Lymphatic ECFCs are significantly more susceptible to KSHV infection than the blood ECFCs and maintain the viral episomes during passage in culture while the blood ECFCs lose the viral episome. Only the KSHV-infected lymphatic ECFCs grew to small multicellular colonies in soft agar whereas the infected blood ECFCs and all uninfected ECFCs failed to proliferate. The lymphatic ECFCs express high levels of SOX18, which supported the maintenance of high copy number of KSHV genomes. When implanted subcutaneously into NSG mice, the KSHV-infected lymphatic ECFCs persisted in vivo and recapitulated the phenotype of KS tumor cells with high number of viral genome copies and spindling morphology. These spindle cell hallmarks were significantly reduced when mice were treated with SOX18 inhibitor, SM4. These data suggest that KSHV-infected lymphatic ECFCs can be utilized as a KSHV infection model for in vivo translational studies to test novel inhibitors representing potential treatment modalities for KS. Author summaryKaposis sarcoma herpesvirus (KSHV) is the etiologic agent of Kaposis sarcoma (KS). The main proliferative component of KS, spindle cells, express markers of lymphatic and blood endothelium. Endothelial precursor cells, which are circulating endothelial colony forming cells (ECFCs), have been proposed as the source of spindle cells. Here we examined both blood and lymphatic ECFCs infected with KSHV. Lymphatic ECFCs are readily infected by KSHV, maintain the viral episomes and show minimal transformation of the cells, which the infected blood ECFCs and all uninfected ECFCs failed to show. The lymphatic ECFCs express SOX18, which supported the maintenance of high copy numbers of KSHV genomes. The KSHV-infected lymphatic ECFCs persisted in vivo and recapitulated the phenotype of KS tumor cells such as high number of viral genome copies and spindling morphology. These KS tumor cell hallmarks were significantly reduced by SOX18 chemical inhibition using a small molecule SM4 treatment. These data suggest that KSHV-infected lymphatic ECFCs could be the progenitors of KS spindle cells and are a promising model for the translational studies to develop new therapies for KS.

microbiology↗

bioRxiv2022

Heparin-derived theranostic nanoprobes overcome the blood-brain barrier and target glioma in murine model

The poor permeability of theranostic agents across the blood-brain-barrier (BBB) significantly hampers the development of new treatment modalities for neurological diseases. We have discovered a new biomimetic nanocarrier using heparin (HP) that effectively passes the BBB and targets glioblastoma. Specifically, we designed HP coated gold nanoparticles (HP-AuNPs) that were labeled with three different imaging modalities namely, fluorescein (FITC-HP-AuNP), radioisotope 68Gallium (68Ga-HP-AuNPs), and MRI active gadolinium (Gd-HP-AuNPs). The systemic infusion of FITC-HP-AuNPs in three different mouse strains (C57BL/6JRj, FVB, and NMRI-nude) displayed excellent penetration and revealed uniform distribution of fluorescent particles in the brain parenchyma (69-86%) with some accumulation in neurons (8-18%) and microglia (4-10%). Tail-vein administration of radiolabeled 68Ga-HP-AuNPs in healthy rats also showed 68Ga-HP-AuNP inside the brain parenchyma and in areas containing cerebrospinal fluid, such as the lateral ventricles, the cerebellum, and brain stem. Finally, tail-vein administration of Gd-HP-AuNPs (that display [~]3 fold higher relaxivity than that of commercial Gd-DTPA) in an orthotopic glioblastoma (U87MG xenograft) model in nude mice demonstrated enrichment of T1-contrast at the intracranial tumor with a gradual increase in the contrast in the tumor region between 1h-3h. We believe, our finding offers the untapped potential of HP-derived-NPs to deliver cargo molecules for treating neurological disorders.

bioengineering↗

bioRxiv2020

Circumventing drug treatment? Polyethylenimine functionalized nanoparticles inherently and selectively kill patient-derived glioblastoma stem cells

Glioblastoma (GB) is the most frequent malignant tumor originating from the central nervous system. Despite breakthroughs in treatment modalities for other cancer types, GB remains largely irremediable due to its high degree of intratumoral heterogeneity, infiltrative growth, and intrinsic resistance towards multiple treatments. These resistant and aggressive sub-populations of GBs including the glioblastoma stem cells (GSCs) can circumvent treatment. GSCs act as a reservoir of cancer-initiating cells; they are a major challenge for successful therapy. We have discovered, as opposed to well-reported anti-cancer drug based therapeutical approach for GB therapy, the role of polyethylenimine (PEI) in inducing selective death of patient-derived GSCs via lysosomal membrane rupturing. Even at very low doses (1 g/ml), PEI surface-functionalized mesoporous silica nanoparticles (PEI-MSNs), without any additional anti-cancer drug, very potently and selectively killed multiple GSC lines. Very importantly, PEI-MSNs did not affect the survival of well-established GB cells, or other type of cancer cells even at 25x higher doses. Remarkably, any sign of predominant cell death pathways such as apoptosis and autophagy was absent. Instead, as a potential explanation for their GSC selective killing function, we demonstrate that the internalized PEI-MSNs accumulated inside the lysosomes, subsequently causing a rupture of the vulnerable lysosomal membranes, exclusively in GSCs. As a further evaluation, we observed blood-brain-barrier (BBB) permeability of these PEI-MSNs in vitro and in vivo. Taking together the recent indications for the vulnerability of GSCs for lysosomal targeting, and GSC selectivity of the PEI-MSNs described here, the results suggest that PEI-functionalized nanoparticles could have a potential role in the eradication of GSCs.

cancer biology↗

bioRxiv2019

Prostate Specific Membrane Antigen expression in the vasculature of primary lung carcinomas associates with faster metastatic dissemination to brain

Glioblastomas and brain metastases (BM) of solid tumors are the most common central nervous system neoplasms associated with very unfavorable prognosis. In this study, we report the association of Prostate Specific Membrane Antigen with various clinical parameters in a large cohort of primary and secondary brain tumors. A tissue micro array containing 371 cases of ascending grade gliomas pertaining to astrocytic origin, samples of 52 cases of primary lung carcinomas with matching brain metastases with follow-up time accounting to 10.4 years was evaluated for PSMA expression using immunohistochemistry. In addition, PSMA expression was studied in brain metastases arising from melanomas and breast carcinomas. Neovascular expression of PSMA was evident alongside with high expression in the proliferating microvasculature of glioblastomas when compared to the tumor cell expression. This result corroborated with the results obtained from the in silico (cancer genome databases) analyses. In the matched primary lung cancers and their brain metastases (n = 52), vascular PSMA expression in primary tumors led to significantly accelerated metastatic dissemination to the brain with a tendency towards poor overall survival. Taken together, we report the vascular expression of PSMA in the primary and secondary brain tumors that globally associates with the malignant progression and poor outcome of the patients.

pathology↗

bioRxiv2019

Monotherapy efficacy of BBB-permeable small molecule activators of PP2A in glioblastoma

Glioblastoma (GB) is a fatal disease in which most targeted therapies have clinically failed. However, pharmacological reactivation of tumor suppressors has not been thoroughly studied as yet as a GB therapeutic strategy. Tumor suppressor Protein Phosphatase 2A (PP2A), is inhibited by non-genetic mechanisms in GB, and thus it would be potentially amendable for therapeutic reactivation. Here we demonstrate, that small molecule activators of PP2A (SMAPs), NZ-8-061 and DBK-1154, effectively cross the in vitro model of blood-brain barrier (BBB), and in vivo partition to mouse brain tissue after oral dosing. In vitro, SMAPs exhibit robust cell killing activity against five established GB cell lines, and nine patient-derived primary glioma cell lines. Collectively these cell lines have heterogenous genetic background, kinase inhibitor resistance profile, and stemness properties; and they represent different clinical GB subtypes. Oral dosing of either of the SMAPs significantly reduced growth of infiltrative intracranial GB tumors. DBK-1154, with both higher degree of brain/blood distribution, and more potent in vitro activity against all tested GB cell lines, also significantly increased survival of mice bearing orthotopic GB xenografts. In summary, this report presents a proof-of-principle data for BBB-permeable tumor suppressor reactivation therapy for glioblastoma cells of heterogenous molecular background.

cancer biology↗

bioRxiv2018

Vulnerability of invasive glioma cells to lysosomal membrane instabilization

Diffusive by nature, glioma challenges clinical care by the impossibility of complete surgical resection of tumor, leaving the radio- and chemoresistant cells responsible for recurrence intact. We identified mammary-derived growth inhibitor (MDGI/FABP3) as invasive glioma biomarker. Here, we show that high MDGI expression associated with poor patient survival and promoted invasive glioma cell growth both in vitro and in vivo, while MDGI silencing drastically compromised patient-derived tumoroid viability via induction of lysosomal membrane permeabilization (LMP). This alternative cell death pathway provokes release of lysosomal hydrolases into the cytosol leading inevitably to the cell death. Our results show a novel functional role for MDGI in glioma cell invasion, survival, and maintenance of the lysosomal membrane integrity as well as an unsuspected sensitivity of glioma cells to an LMP-inducing drug, anti-histamine clemastine. In a preclinical study, clemastine-treatment significantly prolonged the survival of intracranial glioblastoma-bearing animals due to eradication of invasive glioma cells. This glioma cell vulnerability to LMP-inducing drugs opens new horizons for development of novel treatments and suggest re-positioning of an established drug for new indication.

cancer biology↗