Anti-C1-inactivator treatment of glioblastoma

Purpose: Glioblastoma multiforme (GBM) or astrocytoma grade IV is the most common type of primary brain tumor in adults. In the present study, we investigate the role of the complement system in the glioblastoma situation in an experimental model, since we have previously been able to show a blockade of this system in the glioblastoma setting. Technique and results: A GFP-positive glioblastoma cell line was used to induce glioblastomas subcutaneously in rats (n=42). Antibodies against C1-Inactivator (C1-IA) were used to try to re-activate the complement system. We were able to demonstrate an increased survival in rats treated with anti-C1-IA with an intratumoral route, and we could establish the same the results in a second series. Serum analyses revealed decreased levels of IL-1b and GM-CSF in animals 24 days after tumor cell inoculation in the anti-C1-IA group when compared to controls. Immunohistochemistry revealed decreased expression of C1-IA following treatment. Interpretation: These results are in line with our previous work showing an upregulation of C1-IA, which is able to block the classical complement pathway, in glioblastomas. Treatment with antibodies against C1-IA seems to be beneficial in the glioblastoma situation, and no side effects could be seen in our experiments

Upregulation of C1-inhibitor in pancreatic cancer

Purpose: The complement system has recently sparked more interest in cancer research. The classical pathway is initiated by activation of the C1 complex, which irreversibly can be bound to and inhibited by C1-INH. We have previously shown that C1-INH is upregulated in human glioblastoma (astrocytoma grade IV) on both gene and protein level. We here examine whether the complement system seems to play a role also in pancreatic cancer.Technique and results: We performed an expression analysis of complement associated genes in 36 pancreatic ductal adenocarcinoma tumors and matching normal pancreatic tissue samples from pancreatic cancer patients (data from the publicly available database GSE15471). C1-INH was significantly upregulated in the pancreatic cancer tissue. None of the downstream components of the cascade were significantly upregulated in the cancer samples as compared to the control samples, which is the same pattern as we found in glioblastoma. GO analysis showed that membrane attack complex came up as the second most significantly associated cellular component. Analyzing gene expression of C1-INH in the pancreatic cancer cell lines from primary tumors versus metastatic tumor revealed no difference for the two mRNA transcripts (GSE59357).Interpretation: Analysis of gene expression of complement related genes shows an upregulation of C1-INH and a downregulation of downstream components. This could suggest that C1-INH plays a role also in pancreatic cancer

C1-inactivator is upregulated in glioblastoma

Background: Glioblastoma is the most common and aggressive type of primary brain tumor in adults. A key problem is the capacity of glioma cells to inactivate the body’s immune response. The complement system acts as a functional bridge between the innate and adaptive immune response. Still, the role of the complement system has almost been forgotten in glioma research. In our present study, we hypothesize that C1 inactivator (C1-IA) is upregulated in astrocytoma grade IV, and that its inhibition of the complement system has beneficial effects upon survival. Methods and results: We have explored this hypothesis both on gene and protein levels and found an upregulation of C1-IA in human glioblastoma cells using data from a publicly available database and our own mRNA material from glioblastoma patients. Furthermore, we demonstrated the presence of C1-IA by using immunohistochemistry on glioma cells from both humans and rats in vitro. Finally, we could demonstrate a significantly increased survival in vivo in animals inoculated intracerebrally with glioma cells pre-coated with C1-IA antibodies as compared to control animals. Conclusions: Our findings indicate that overexpression of C1-IA is present in glioblastomas. This could be demonstrated both at the gene level from patients with glioblastoma, on mRNA level and with immunohistochemistry. Treatment with antibodies against C1-IA had beneficial effects on survival when tested in vivo

What is the role of CRP in glioblastoma?

Background: Glioblastoma is the most common primary malignant brain tumor in adults. Previous studies have suggested that CRP (C-reactive protein) could serve as a biomarker candidate as well as a prognostic factor in glioblastoma patients, and we here further investigate its potential role. Materials and methods: Publicly available datasets were used to compare gene expression between brain samples from glioblastoma patients and non-tumor tissue. The structure of CRP was compared between humans and rats. Glioblastoma cells from humans and rats were stained with anti-CRP. Fischer 344 rats were inoculated with syngeneic glioblastoma cells pre-coated with anti-CRP, and survival was monitored. CRP concentration in rats carrying glioblastoma was followed. Results: CRP was upregulated on one locus on gene level in glioblastoma tissue as compared to non-tumor brain tissue, but not in glioma stem cells as compared to neural stem cells. The structure of the CRP protein was a characteristic pentamer in both humans and rats. Both human and rat glioblastoma cells were clearly positive for anti-CRP staining. Pre-coating of glioblastoma cells with anti-CRP antibodies did not affect survival in rats with intracranial tumors. Serum levels of CRP increased during tumor progression but did not reach significantly different levels. Conclusions: Both human and rat glioblastoma cells could be stained with anti-CRP antibodies in vitro. In a syngeneic glioblastoma rat model we could see an increase in serum CRP during tumor progression, but coating glioblastoma cells with anti-CRP antibodies did not provide any survival change for the animals

Complement Components in Peripheral Blood from Adult Patients with IDH Wild-Type Glioblastoma

Background: The complement system seems to influence cancer pathophysiology. The primary aim of this study was to explore complement components associated with the classical pathway (CP) of the complement system in peripheral blood from patients with IDH–wild-type (IDH-wt) glioblastoma. Methods: Patients undergoing primary surgery due to glioblastoma in the years 2019–2021 were prospectively included in the present study. Blood samples were collected prior to surgery, and analyzed with regard to CP complement components, as well as standard coagulation tests. Results: In total, 40 patients with IDH-wt glioblastomas were included. C1q was reduced in 44% of the cases compared to the reference interval. C1r was reduced in 61% of the analyzed samples. Both C1q and C1r are parts of the initial steps of the classical complement activation pathway, which, however, was not correspondingly altered. Activated pro-thromboplastin time (APTT) was shorter in 82% of the analyzed samples compared to the reference interval. APTT was shorter in those with reduced C1q and C1r levels. C1q is an important link between the innate and acquired immunity, and C1q and C1r also interact with the coagulation system. Patients who displayed reduced levels of both C1q and C1r preoperatively had a significantly shorter overall survival compared with the rest of the cohort. Conclusions: Our findings demonstrate that there are alterations in C1q and C1r concentrations in peripheral blood from patients with IDH1-wt glioblastoma compared with the normal population. Patients who displayed reduced C1q and C1r levels had a significantly shorter survival

Combined anti-C1-INH and radiotherapy against glioblastoma

Abstract Background A more effective immune response against glioblastoma is needed in order to achieve better tumor control. Radiotherapy can induce anti-tumor mediated immune reactions, in addition to its dose response effects. The complement system can function as a bridge between innate and adaptive immune responses. Combining radiotherapy and complement activating therapy is theoretically interesting. Methods Radiotherapy at 8 Gy × 2 was combined with treatment against C1-inhibitor (C1-INH), a potent inhibitor of activation of the classical pathway of the complement system. Anti-C1-INH was delivered as intratumoral injections. Fully immunocompetent Fischer 344 rats with NS1 glioblastoma tumors were treated. Survival was monitored as primary outcome. Models with either intracranial or subcutaneous tumors were evaluated separately. Results In the intracranial setting, irradiation could prolong survival, but there was no additional survival gain as a result of anti-C1-INH treatment. In animals with subcutaneous tumors, combined radio-immunotherapy with anti-C1-INH and irradiation at 8 Gy × 2 significantly prolonged survival compared to control animals, whereas irradiation or anti-C1-INH treatment as single therapies did not lead to significantly increased survival compared to control animals. Conclusions Anti-C1-INH treatment could improve the efficacy of irradiation delivered at sub-therapeutic doses and delay tumor growth in the subcutaneous tumor microenvironment. In the intracranial setting, the doses of anti-C1-INH were not enough to achieve any survival effect in the present setting

C1-inactivator is upregulated in glioblastoma - Fig 3

<p>Also in our own rat glioblastoma cell line with homozygously GFP-positive cells, C1-IA could be demonstrated both A) with the human anti-C1-IA and B) with the rat anti-C1-IA.</p

Demonstration of C1-IA at the protein expression level in human glioblastoma cells.

<p>The antibody binding seems to be localized to the cell membrane and cytoplasm.</p

Protein structure for (left) human C1-IA and (right) rat C1-IA (model from Swissmodel.expasy.org).

<p>The human C1-IA consists of 500 amino acids, whereas the rat C1-IA consists of 504 amino acids with a sequence identity of 78.57%.</p

Gene expression analysis showing upregulation of complement associated genes in two independent data sets.

<p>Figs show fold change of group mean expression values with 95% confidence interval for astrocytoma grade IV vs. non-tumor brain in a data set from a publicly available database (Fig 1A) and our own institution (Fig 1B). Confidence intervals for C1α and C1qɤ lie outside the scale. Significance levels are indicated as *p<0.05, **p<0.01, and ***p<0.001.</p