Hydroxychloroquine overcomes cabergoline resistance in a patient with Lactotroph Pituitary neuroendocrine tumor: a case report

Targeting Autophagy for Pituitary Tumors

Pituitary tumors, arising from the pituitary gland, can be classified as functioning or non-functioning based on their hormone production. Previous studies demonstrated that impairment of cellular processes, such as autophagy, a crucial cellular recycling mechanism, has been implicated in pituitary tumorigenesis and hormone dysregulation. This review comprehensively examines the intricate relationship between autophagy and pituitary tumors. We explore the multifaceted role of autophagy in cancer, highlighting its dual nature as both a tumor suppressor and a promoter depending on the context. We also discuss the specific mechanisms of autophagy, including macroautophagy, mitophagy, crinophagy, and their relevance to pituitary tumorigenesis and hormone regulation. Furthermore, we analyze the current literature regarding the impact of various therapeutic interventions in pituitary tumor cells, with both autophagy-promoting and autophagy-inhibiting strategies. We address the challenges in interpreting autophagy activity and its complex interplay with hormone production. Current evidence suggests the potential of targeting autophagy as a therapeutic approach for pituitary tumors, emphasizing further research and clinical trials to determine the optimal strategy for individual patients and improve long-term outcomes.

Single-cell transcriptomics reveal distinct immune-infiltrating phenotypes and macrophage-tumor interaction axes among different lineages of pituitary neuroendocrine tumors

BACKGROUND

Pituitary neuroendocrine tumors (PitNETs) are common gland neoplasms demonstrating distinctive transcription factors. Although the role of immune cells in PitNETs has been widely recognized, the precise immunological environment and its control over tumor cells are poorly understood.

METHODS

The heterogeneity, spatial distribution, and clinical significance of macrophages in PitNETs were analyzed using single-cell RNA sequencing (scRNA-seq), bulk RNA-seq, spatial transcriptomics, immunohistochemistry, and multiplexed quantitative immunofluorescence (QIF). Cell viability, cell apoptosis assays, and in vivo subcutaneous xenograft experiments have confirmed that INHBA-ACVR1B influences the process of tumor cell apoptosis.

RESULTS

The present study evaluated scRNA-seq data from 23 PitNET samples categorized into 3 primary lineages. The objective was to explore the diversity of tumors and the composition of immune cells across these lineages. Analyzed data from scRNA-seq and 365 bulk RNA sequencing samples conducted in-house revealed the presence of three unique subtypes of tumor immune microenvironment (TIME) in PitNETs. These subtypes were characterized by varying levels of immune infiltration, ranging from low to intermediate to high. In addition, the NR5A1 lineage is primarily associated with the subtype characterized by limited infiltration of immune cells. Tumor-associated macrophages (TAMs) expressing CX3CR1+, C1Q+, and GPNMB+ showed enhanced contact with tumor cells expressing NR5A1 + , TBX19+, and POU1F1+, respectively. This emphasizes the distinct interaction axes between TAMs and tumor cells based on their lineage. Moreover, the connection between CX3CR1+ macrophages and tumor cells via INHBA-ACVR1B regulates tumor cell apoptosis.

CONCLUSIONS

In summary, the different subtypes of TIME and the interaction between TAM and tumor cells offer valuable insights into the control of TIME that affects the development of PitNET. These findings can be utilized as prospective targets for therapeutic interventions.

Therapeutic potential of targeting Nrf2 by panobinostat in pituitary neuroendocrine tumors

We aimed to identify the druggable cell-intrinsic vulnerabilities and target-based drug therapies for PitNETs using the high-throughput drug screening (HTS) and genomic sequencing methods. We examined 9 patient-derived PitNET primary cells in HTS. Based on the screening results, the potential target genes were analyzed with genomic sequencing from a total of 180 PitNETs. We identified and verified one of the most potentially effective drugs, which targeted the Histone deacetylases (HDACs) both in in vitro and in vivo PitNET models. Further RNA sequencing revealed underlying molecular mechanisms following treatment with the representative HDACs inhibitor, Panobinostat. The HTS generated a total of 20,736 single-agent dose responses which were enriched among multiple inhibitors for various oncogenic targets, including HDACs, PI3K, mTOR, and proteasome. Among these drugs, HDAC inhibitors (HDACIs) were, on average, the most potent drug class. Further studies using in vitro, in vivo, and isolated PitNET primary cell models validated HDACIs, especially Panobinostat, as a promising therapeutic agent. Transcriptional surveys revealed substantial alterations to the Nrf2 signaling following Panobinostat treatment. Moreover, Nrf2 is highly expressed in PitNETs. The combination of Panobinostat and Nrf2 inhibitor ML385 had a synergistic effect on PitNET suppression. The current study revealed a class of effective anti-PitNET drugs, HDACIs, based on the HTS and genomic sequencing. One of the representative compounds, Panobinostat, may be a potential drug for PitNET treatment via Nrf2-mediated redox modulation. Combination of Panobinostat and ML385 further enhance the effectiveness for PitNET treatment.

How to manage intolerance to dopamine agonist in patients with prolactinoma

PURPOSE

Dopamine agonists (DA) are the gold-standard for prolactinoma and hyperprolactinemia treatment. Intolerance to DA leading to drug drop out occurs in 3 to 12% of cases. We provide here a review of published data about DA intolerance and present a case report concerning the use of intravaginal cabergoline.

METHODS

We review the literature on the definition, the pathogenesis, frequency and management of DA intolerance. In addition, the review provides strategies to enhance tolerability and avoid precocious clinical treatment withdrawal.

RESULTS

Cabergoline is often cited as the most tolerable DA and its side effects tend to ameliorate within days to weeks. Restarting the same drug at a lower dose or switching to another DA can be used in cases of intolerance. The vaginal route can be tried specifically if there are gastrointestinal side effects in the oral administration. Symptomatic treatment could be attempted, although mainly based on a strategy used in other diseases.

CONCLUSIONS

Due to limited data, no guidelines have been developed for the management of intolerance in DA treatment. The most frequent management is to perform transsphenoidal surgery. Nevertheless, this manuscript provides data derived from published literature and expert opinion, suggesting new approaches to this clinical issue.