Immunotherapy and potential molecular targets for the treatment of pituitary adenomas resistant to standard therapy: a critical review of potential therapeutic targets and current developments

Advancements in Molecular Diagnosis and Pharmacotherapeutic Strategies for Invasive Pituitary Adenomas

BACKGROUND

The overwhelming majority of pituitary tumors consist of pituitary adenomas (PAs), which have recently also been termed pituitary neuroendocrine tumors (PitNETs). Clinically significant PAs occur in approximately one in every 1000 individuals, while other types of pituitary tumors, such as craniopharyngiomas and pituicytomas, are significantly less common. Although PAs are generally benign, a subset of them exhibits malignant-like biological traits. They tend to infiltrate and grow aggressively into adjacent tissues and organs, including the dura mater, cavernous sinus, and sphenoid sinus. This invasive behavior often results in the destruction of the normal anatomical architecture of the sella turcica and skull base. Clinically, such tumors are classified as invasive PAs (IPAs), emphasizing their aggressive and destructive nature.

OBJECTIVE AND SIGNIFICANCE

Currently, the diagnostic indicators for IPAs frequently suffer from suboptimal sensitivity and specificity. The invasiveness assessment of PAs lacks a definitive gold standard and instead serves as a predictive tool, with a greater number of indicators met suggesting a higher likelihood of invasiveness. Consequently, a comprehensive approach that integrates imaging, pathological, molecular biological, and other disciplinary metrics is crucial for accurate evaluation. Despite surgery being the primary treatment modality for IPAs, their malignant-like behavior complicates complete resection, resulting in lower resection rates and heightened postoperative recurrence, necessitating multiple surgeries. Therefore, adjunctive drug therapy is often necessary for IPA patients. Preoperative drug therapy can shrink tumor size, facilitating resection and postoperative recovery, mitigating hormone imbalances, delaying recurrence, and enhancing patients' quality of life.

CONCLUSIONS

This article comprehensively reviews the diagnostic criteria for assessing the invasiveness of PAs in the domains of imaging, pathology, and molecular biology, provides an overview of the current research status of drug therapy for these conditions, and deepens our insight into the biological and therapeutic aspects of the tumor microenvironment in PAs.

Tumor immune microenvironment in pituitary neuroendocrine tumors (PitNETs): increased M2 macrophage infiltration and PD-L1 expression in PIT1-lineage subset

PURPOSE

Tumor immune microenvironment in pituitary neuroendocrine tumors (PitNETs) and application of current immunotherapy for refractory PitNETs remains debated. We aim to evaluate the immune landscape in different lineages of PitNETs and determine the potential role of pituitary transcription factors in reshaping the tumor immune microenvironment (TIME), thus promoting the application of current immunotherapy for aggressive and metastatic PitNETs.

METHODS

Immunocyte infiltration and expression patterns of immune checkpoint molecules in different lineages of PitNETs were estimated via in silico analysis and validated using an IHC validation cohort. The correlation between varying immune components with clinicopathological features was assessed in PIT1-lineage PitNETs.

RESULTS

Transcriptome profiles from 210 PitNETs/ 8 normal pituitaries (NPs) and immunohistochemical validations of 77 PitNETs/6 NPs revealed a significant increase in M2-macrophage infiltration in PIT1-lineage PitNETs, compared with the TPIT-lineage, SF1-lineage subsets and NPs. While CD68 + macrophage, CD4 + T cells, and CD8 + T cells were not different among them. Increased M2-macrophage infiltration was associated with tumor volume (p < 0.0001, r = 0.57) in PIT1-lineage PitNETs. Meanwhile, differentially expressed immune checkpoint molecules (PD-L1, PD1, and CTLA-4) were screened and validated in IHC cohorts. The results showed that PD-L1 was highly expressed in PIT1-lineage subsets, and PD-L1 overexpression showed a positive correlation with tumor volume (p = 0.04, r = 0.29) and cavernous sinus invasion (p < 0.0001) in PIT1-lineage PitNETs.

CONCLUSION

PIT1-lineage PitNETs exhibit a distinct immune profile with enrichment of M2 macrophage infiltration and PD-L1 expression, which may contribute to its clinical aggressiveness. Application of current immune checkpoint inhibitors and M2-targeted immunotherapy might be more beneficial to treat aggressive and metastatic PIT-lineage PitNETs.

INTERLEUKIN-6 AND NKG2D AS PROGNOSTIC FACTORS IN IRAQI FEMALES WITH PITUITARY GAND ADENOMA: A LONGITUDINAL STUDY

OBJECTIVE

The aim: To assess the role of circulating IL-6 & NKG2D in the prognosis of pituitary adenoma.

PATIENTS AND METHODS

Materials and methods: Thirty female with new diagnosis of prolactinoma (pituitary gland adenoma) were enrolled in the study. ELISA test was used to evaluate the level of IL6 and NKG2D. ELISA tests were conducted before the initiation of treatment and six months later.

RESULTS

Results: There are significant differences in mean levels of IL-6 and NKG2D, and the anatomical type (tumor size) (-418.7 & 418.9, p<0.001) of anatomical tumor (-373.72 & -373.920, p=0.001). There is a significant difference between the two immunological markers (IL-6 & NKG2D) (-0.305; p<0.001). The IL-6 markers significantly decreased in means on follow up (-197.8; p-value≤0.0001) while the reverse occur in NKG2D, which increased in levels post-treatment compared with baseline measurement. The high expression of IL-6 positively correlated with the risk of macroadenoma (>10 microns) and poor resonse to treatment and vice versa (p<0.024). High expression of NKG2D significantly (p<0.005) correlated with good prognosis and increased chance for tumor response to medicine and shrinkage in size compared with low concentration.

CONCLUSION

Conclusions: The higher the level of IL-6, the larger the size of adenoma (macroadenoma) and the poorer the response to treatment. The higher the level of NKG2D indidcate a better prognosis, therefore, IL-6 and NKG2D correlate negatively in prolactinoma patients.

Research advances on the immune research and prospect of immunotherapy in pituitary adenomas

Background

Pituitary adenomas are one type of intracranial tumor, which can be divided into microadenoma (≤ 1 cm), macroadenoma (> 1 cm), and giant adenoma (≥ 4 cm) according to their diametral sizes. They are benign, typically slow-progressing, whereas the biological behavior of some of them is invasive, which presents a major clinical challenge. Treatment of some pituitary adenomas is still difficult due to drug resistance or multiple relapses, usually after surgery, medication, and radiation. At present, no clear prediction and treatment biomarkers have been found in pituitary adenomas and some of them do not cause clinical symptoms, so patients are often found to be ill through physical examination, and some are even found through autopsy. With the development of research on pituitary adenomas, the immune response has become a hot spot and may serve as a novel disease marker and therapeutic target.

The distribution and function of immune cells and their secreted molecules in pituitary adenomas are extremely complex. Researchers found that infiltration of immune cells may have a positive effect on the treatment and prognosis of pituitary adenomas. In this review, we summarized the advance of tumor immunity in pituitary adenomas, revealing the immunity molecules as potential biomarkers as well as therapeutic agents for pituitary adenomas.

Conclusion

The immune studies related to pituitary adenomas may help us find relevant immune markers. At the same time, the exploration of immunotherapy also provides new options for the treatment of pituitary adenomas.

The Immune Profile of Pituitary Adenomas and a Novel Immune Classification for Predicting Immunotherapy Responsiveness

CONTEXT

The tumor immune microenvironment is associated with clinical outcomes and immunotherapy responsiveness.

OBJECTIVE

To investigate the intratumoral immune profile of pituitary adenomas (PAs) and its clinical relevance and to explore a novel immune classification for predicting immunotherapy responsiveness.

DESIGN, PATIENTS, AND METHODS

The transcriptomic data from 259 PAs and 20 normal pituitaries were included for analysis. The ImmuCellAI algorithm was used to estimate the abundance of 24 types of tumor-infiltrating immune cells (TIICs) and the expression of immune checkpoint molecules (ICMs).

RESULTS

The distributions of TIICs differed between PAs and normal pituitaries and varied among PA subtypes. T cells dominated the immune microenvironment across all subtypes of PAs. The tumor size and patient age were correlated with the TIIC abundance, and the ubiquitin-specific protease 8 (USP8) mutation in corticotroph adenomas influenced the intratumoral TIIC distributions. Three immune clusters were identified across PAs based on the TIIC distributions. Each cluster of PAs showed unique features of ICM expression that were correlated with distinct pathways related to tumor development and progression. CTLA4/CD86 expression was upregulated in cluster 1, whereas programmed cell death protein 1/programmed cell death 1 ligand 2 (PD1/PD-L2) expression was upregulated in cluster 2. Clusters 1 and 2 exhibited a "hot" immune microenvironment and were predicted to exhibit higher immunotherapy responsiveness than cluster 3, which exhibited an overall "cold" immune microenvironment.

CONCLUSIONS

We summarized the immune profile of PAs and identified 3 novel immune clusters. These findings establish a foundation for further immune studies on PAs and provide new insights into immunotherapy strategies for PAs.

Endoglin (CD105) and VEGF as potential angiogenic and dissemination markers for colorectal cancer

Background

Colorectal cancer (CRC) is an important current problem concerning public health due to its high incidence and mortality. Advances in molecular and cellular knowledge and the detection of new disease biomarkers are very important to improve prognosis, prediction, and early diagnosis. In this study, we aimed to analyze the gene and protein expression levels of two angiogenic markers, VEGF and soluble Endoglin, during different tumor stages as well as at different stages of cancer treatment, to predict the diagnosis and evolution of colon and rectal cancer.

Material and methods

This study includes 133 CRC patients (93 with colon cancer and 40 with rectal cancer) on which the gene and protein expression of Endoglin (membrane and soluble form) and VEGF were analyzed by molecular and immunohistochemical techniques on different tumor stage samples and plasma obtained preoperatively as well as 3, 6, and 9 months after resection of the tumor.

Results

VEGF and Endoglin gene expressions were higher in tumor tissue than in surrounding non-tumoral tissue for both types of cancer. The VEGF levels in plasma were found to decrease in less aggressive tumors, whereas soluble Endoglin was increased in preoperative samples of patients with metastasis. Membrane Endoglin expression was higher on the vascular endothelium of more aggressive tumors. In contrast, Endoglin expression was mainly in the colon epithelium in less aggressive stage tumors.

Conclusion

Endoglin and VEGF are proteins with a major role in the tumor angiogenesis process. This study performed with a wide cohort of human samples shows that both proteins seem to be valuable biomarkers in the diagnosis and prognosis of CRC.

Mitochondrial Dysfunction Pathway Networks and Mitochondrial Dynamics in the Pathogenesis of Pituitary Adenomas

Mitochondrion is a multi-functional organelle, which is associated with various signaling pathway networks, including energy metabolism, oxidative stress, cell apoptosis, cell cycles, autophagy, and immunity process. Mitochondrial proteins have been discovered to modulate these signaling pathway networks, and multiple biological behaviors to adapt to various internal environments or signaling events of human pathogenesis. Accordingly, mitochondrial dysfunction that alters the bioenergetic and biosynthetic state might contribute to multiple diseases, including cell transformation and tumor. Multiomics studies have revealed that mitochondrial dysfunction, oxidative stress, and cell cycle dysregulation signaling pathways operate in human pituitary adenomas, which suggest mitochondria play critical roles in pituitary adenomas. Some drugs targeting mitochondria are found as a therapeutic strategy for pituitary adenomas, including melatonin, melatonin inhibitors, temozolomide, pyrimethamine, 18 beta-glycyrrhetinic acid, gossypol acetate, Yougui pill, T-2 toxin, grifolic acid, cyclosporine A, dopamine agonists, and paeoniflorin. This article reviews the latest experimental evidence and potential biological roles of mitochondrial dysfunction and mitochondrial dynamics in pituitary adenoma progression, potential molecular mechanisms between mitochondria and pituitary adenoma progression, and current status and perspectives of mitochondria-based biomarkers and targeted drugs for effective management of pituitary adenomas.