Effectiveness and safety of PD-1/PD-L1 inhibitors monotherapy in patients with endometrial cancer

BACKGROUND

Studies evaluating the effectiveness of immune checkpoint inhibitors (ICI) for endometrial cancer (EC) are limited. This study aimed to assess the efficacy of PD-1/PD-L1 inhibitors as monotherapy for EC by conducting a meta-analysis. The predictive significance of MMR status, a biomarker for ICI response, also required further investigation.

METHODS

A systematic literature search was conducted in English databases until September 2023. The analysis included objective response rate (ORR), disease control rate (DCR), adverse events (AEs), and odds ratios (OR), along with their corresponding 95% confidence intervals (CI).

RESULTS

There were twelve trials totaling 685 individuals. PD-1/PD-L1 inhibitor monotherapy resulted in an ORR for 34% (95% CI = 24-44%) of the pooled EC patients. Subgroup analysis revealed a significantly higher ORR in dMMR EC (45%) compared to pMMR EC (8%), with an OR of 6.36 (95% CI = 3.64-11.13). The overall DCR was 42%, with dMMR EC at 51% and pMMR EC at 30% (OR = 2.61, 95% CI = 1.69-4.05). Grade three or higher adverse events (AEs) occurred in 15% of cases (95% CI = 9-24%) of the pooled incidence of AEs, which was 68% (95% CI = 65-72%).

CONCLUSIONS

This meta-analysis provides significant evidence for the effectiveness of PD-1/PD-L1 inhibitors as monotherapy for EC. Notably, dMMR EC patients demonstrated superior treatment efficacy with PD-1/PD-L1 inhibitor immunotherapy. Further research is required to explore subclassifications of EC based on dMMR molecular subtypes, enabling improved treatment strategies and outcomes for EC patients.

Clinical and Biochemical Characteristics of Untreated Adult Patients With Resistance to Thyroid Hormone Alpha

Background

Thyroid hormone resistance due to pathogenic variants in thyroid hormone receptor alpha (THRA) is rare and descriptions of patients are sparse. The disorder is probably underdiagnosed as patients may have normal thyroid function tests. Treatment with thyroxine in childhood improves clinical symptoms. However, it is not clear if treatment has beneficial effects if started in adulthood.

Cases

We investigated 4 previously untreated Caucasian adult first-degree-related patients with the THRA c.788C > T, p.(Ala263Val) variant identified by a gene panel for intellectual disability in the index patient. Clinical data and previous investigations were obtained from medical reports.

Results

During childhood and adolescence, short stature, short limbs, metacarpals, and phalanges, and delayed bone age maturation were observed. Delayed motor and language development and decreased intellectual and learning abilities were described. Abdominal adiposity, round face, and increased head circumference were common features. All individuals complained of tiredness, constipation, and low mood. While thyrotropin (TSH) and free thyroxine (FT4) were within the reference range, free triiodothyronine (FT3) was high. FT4/FT3 ratio and reverse T3 were low. Other main features were low hemoglobin and high LDL/HDL ratio.

Conclusion

Investigation of 4 first-degree-related adult patients with untreated resistance to thyroid hormone alpha (RTHα) revealed more pronounced phenotype features and hypothyroid symptoms than previously described in patients treated with levothyroxine from childhood or adolescence. The delay in diagnosis is probably due to normal thyroid function tests. We suggest that THRA analysis should be performed in patients with specific clinical features, as treatment in early childhood may improve outcomes.

Long-term follow-up results and treatment outcomes of children and adults with resistance to thyroid hormone alpha

PURPOSE

Resistance to thyroid hormone alpha (RTHα) is a rare entity and has no specific treatment. To date, mostly levothyroxine has been used, but there is a lack of knowledge about the long-term outcomes of this treatment. We aimed to evaluate the long-term follow-up results and treatment outcomes of children and their parents diagnosed with RTHα.

METHODS

Four children [the median (minimum-maximum) age at diagnosis, 4.5 (1.4-9.5) years] and three adults [age at diagnosis, 31.7 (28.0-35.3) years] from two families were included in the study, who had RTHα and followed up between 2014 and 2021.

RESULTS

The median duration of treatment was 6.7 (5.9-8.0) years, and the levothyroxine dose at the final visit was 1.4 (1.2-2.2) and 1.9 (1.2-2.4) mcg/kg/day for adults and pediatric patients, respectively. Treatment ameliorated constipation in all patients with this complaint (n = 5). Normal mental functions were achieved and IQ scores improved in most children except one (age at diagnosis, 9.5 years). At the final visit, creatine kinase levels relative to the reference upper limit were significantly lower compared to the pre-treatment ratios [0.9 (0.2-1.3) vs. 1.3 (0.5-1.6), p = 0.028]. Anemia was present in five patients at diagnosis, which resolved in one adult patient but occurred in one child despite treatment (p = 0.999). A minimal pericardial effusion persisted in one pediatric patient.

CONCLUSIONS

We demonstrated that constipation was ameliorated, neuromotor development of some children was improved, and creatine kinase levels were diminished with levothyroxine treatment in patients with RTHα, while some features including anemia did not resolve.

Regulation of the THRA gene, encoding the thyroid hormone nuclear receptor TRα1, in intestinal lesions

The THRA gene, encoding the thyroid hormone nuclear receptor TRα1, is expressed in an increasing gradient at the bottom of intestinal crypts, overlapping with high Wnt and Notch activities. Importantly, THRA is upregulated in colorectal cancers, particularly in the high-Wnt molecular subtype. The basis of this specific and/or altered expression pattern has remained unknown. To define the mechanisms controlling THRA transcription and TRα1 expression, we used multiple in vitro and ex vivo approaches. Promoter analysis demonstrated that transcription factors important for crypt homeostasis and altered in colorectal cancers, such as transcription factor 7-like 2 (TCF7L2; Wnt pathway), recombining binding protein suppressor of hairless (RBPJ; Notch pathway), and homeobox protein CDX2 (epithelial cell identity), modulate THRA activity. Specifically, although TCF7L2 and CDX2 stimulated THRA, RBPJ induced its repression. In-depth analysis of the Wnt-dependent increase showed direct regulation of the THRA promoter in cells and of TRα1 expression in murine enteroids. Given our previous results on the control of the Wnt pathway by TRα1, our new results unveil a complex regulatory loop and synergy between these endocrine and epithelial-cell-intrinsic signals. Our work describes, for the first time, the regulation of the THRA gene in specific cell and tumor contexts.

Retrospective analysis and literature review of four cases of thyroid hormone resistance syndrome caused by THRB gene mutation

BACKGROUND

To summarize the clinical characteristics, genetics and follow-up data of four children with thyroid hormone resistance (RTH) syndrome and review the related literatures.

METHODS

The clinical data of the four children diagnosed with RTH syndrome in our hospital from 2018 to 2020 were retrospectively analyzed. Next-generation sequencing of the candidate genes related to thyroid diseases was performed using the blood collected from all the children and their parents who signed an informed consent. Then, relevant cases were retrieved on medical literature databases for analysis and summary.

RESULTS

Among the four cases, three cases of goiter; two cases of tachycardia, palpitations, personality change, hyperactivity, weight loss; one case of academic performance decline, and no hearing and vision loss were observed. Laboratory thyroid function tests indicated a mild increase in free triiodothyronine and with or without increased free thyroxine levels. Thyroid-stimulating hormone (TSH) levels were normal or slightly elevated, but thyrotropin receptor autoantibodies were negative. Octreotide inhibition test showed that the TSH levels of all the children decreased by more than 50% compared with the basal value (the genes of four cases were positive). However, magnetic resonance imaging of the pituitary gland showed no abnormalities. Related gene detection in the children and their families showed that four cases had THRB mutations: two proband mutations were from their fathers, and two cases had de novo mutations.

CONCLUSIONS

The clinical manifestations of pediatric RTH syndrome vary, and the diagnosis mainly depends on thyroid function tests. Heterozygous mutations in THRB are overall rare, even if with the advanced development of next-generation sequencing, not all the children with RTH syndrome have mutations. Furthermore, octreotide inhibition tests cannot be used as a diagnostic criterion to distinguish RTH syndrome from pituitary tumors in children.

7SK Acts as an Anti-tumor Factor in Tongue Squamous Cell Carcinoma

Increasing evidence has shown the mechanistic insights about non-coding RNA 7SK in controlling the transcription. However, the biological function and mechanism of 7SK in cancer are largely unclear. Here, we show that 7SK is down-regulated in human tongue squamous carcinoma (TSCC) and acts as a TSCC suppressor through multiple cell-based assays including a migration assay and a xenograft mouse model. The expression level of 7SK was negatively correlated with the size of tumors in the 73 in-house collected TSCC patients. Through combined analysis of 7SK knockdown of RNA-Seq and available published 7SK ChIRP-seq data, we identified 27 of 7SK-regulated genes that were involved in tumor regulation and whose upstream regulatory regions were bound by 7SK. Motif analysis showed that the regulatory sequences of these genes were enriched for transcription factors FOXJ3 and THRA, suggesting a potential involvement of FOXJ3 and THRA in 7SK-regulated genes. Interestingly, the augmented level of FOXJ3 in TSCC patients and previous reports on THRA in other cancers have suggested that these two factors may promote TSCC progression. In support of this idea, we found that 21 out of 27 aforementioned 7SK-associated genes were regulated by FOXJ3 and THRA, and 12 of them were oppositely regulated by 7SK and FOXJ3/THRA. We also found that FOXJ3 and THRA dramatically promoted migration in SCC15 cells. Collectively, we identified 7SK as an antitumor factor and suggested a potential involvement of FOXJ3 and THRA in 7SK-mediated TSCC progression.

Thyroid Hormone Receptors: Several Players for One Hormone and Multiple Functions

Thyroid hormone receptors (TRs) were cloned based on their homology with the retroviral oncogene v-ERBA. In Vertebrates two genes, THRA and THRB, encode respectively many isotypes and isoforms of receptors TRα and TRβ, resulting from alternative splicing and/or internal transcription start sites. We present here a wide overview of this diversity and of their mechanisms of action as transcription regulators, as well as alternative actions through cytoplasmic signaling.

Syndromes of Resistance to Thyroid Hormone Action

Thyroid hormone (TH) action is crucial for the development of several tissues.A number of syndromes are associated with reduced responsiveness to thyroid hormones, expanding the original definition of thyroid hormone resistance, firstly described by Refetoff and collaborators in 1967, which is characterized by elevated circulating levels of T4 and T3 with measurable serum TSH concentrations, as a consequence of mutations of thyroid hormone receptor beta (TRβ), recently named as RTHβ. More recently, another form of insensitivity to TH has been identified due to mutations in the thyroid hormone receptor alpha (TRα), named RTHα. In this chapter we will focus the discussion on the phenotype of RTHβ and RTHα. These diseases share the same pathogenic mechanism caused by dominant negative mutations in TH receptor genes that reduce T3 binding or affect the recruitment of cofactors. As a consequence, thyroid hormone actions are impaired at the tissue level. The phenotypic manifestations of RTHβ and RTHα are to some extent correlated with the degree of disruption and the tissue distribution of the TRs being characterized by variable coexistence of hypothyroid or thyrotoxic manifestations in RTHβ or by a congenital hypothyroid features in RTHα despite normal TSH and borderline low free T4.

Role of TRs in Zebrafish Development

In recent years, the zebrafish has become a powerful model not only for the developmental biology studies, but also for genetic analyses and drug screenings, mostly thanks to the ease with which its embryos can be manipulated and to its translucent body, which allows in vivo imaging. In this chapter, we will provide an overview of the current knowledge about the role of thyroid hormone receptors during zebrafish embryonic development. Moreover, we will explore the methodologies applied to zebrafish biology to knock down a gene of interest and to analyze in vivo the molecular mechanisms of the mutated receptors.

In vivo Functional Consequences of Human THRA Variants Expressed in the Zebrafish

BACKGROUND

Heterozygous mutations in the thyroid hormone receptor alpha (THRA) gene cause resistance to thyroid hormone alpha (RTHα), a disease characterized by variable manifestations reminiscent of untreated congenital hypothyroidism but a raised triiodothyronine/thyroxine ratio and normal thyrotropin levels. It was recently described that zebrafish embryos expressing a dominant negative (DN) form of thraa recapitulate the key features of RTHα, and that zebrafish and human receptors are functionally interchangeable.

METHODS

This study expressed several human thyroid hormone receptor alpha (hTRα) variants in zebrafish embryos and analyzed the resulting phenotypes.

RESULTS

All hTRα-injected embryos showed variable defects, including cerebral and cardiac edema likely caused by an aberrant looping during heart development, anemia, and an incomplete formation of the vascular network. Moreover, the hTRα-injected embryos presented severe defects of motorneurons and craniofacial development, thus affecting their autonomous feeding and swimming behaviors. Surprisingly, expression of all hTRα mutants had no detectable effect on thyrotropin beta and thyrotropin-releasing hormone transcripts, indicating that their DN action is limited on the thyroid hormone reception beta 2 targets at the hypothalamic/pituitary level in vivo. As previously described in vitro, treatment with high triiodothyronine doses can efficiently revert the observed defects only in embryos injected with missense hTRα variants.

CONCLUSION

Injection of human THRA variants in zebrafish embryos causes tissue-specific defects recapitulating most of the RTHα clinical and biochemical manifestations. The described manipulation of zebrafish embryos represents a novel in vivo model to screen the functional consequences of THRA variants and the rescue potential of new therapeutic compounds.

Patterns of thyroid hormone receptor expression in zebrafish and generation of a novel model of resistance to thyroid hormone action

Resistance to thyroid hormone can be due to heterozygous, dominant negative (DN) THRA (RTHα) or THRB (RTHβ) mutations, but the underlying mechanisms are incompletely understood. Here, we delineate the spatiotemporal expression of TH receptors (TRs) in zebrafish and generated morphants expressing equivalent amounts of wild-type and DN TRαs (thraa_MOs) and TRβs (thrb_MOs) in vivo. Both morphants show severe developmental abnormalities. The phenotype of thraa_MOs includes brain and cardiac defects, but normal thyroid volume and tshba expression. A combined modification of dio2 and dio3 expression can explain the high T3/T4 ratio seen in thraa_MOs, as in RTHα. Thrb_MOs show abnormal eyes and otoliths, with a typical RTHβ pattern of thyroid axis. The coexpression of wild-type, but not mutant, human TRs can rescue the phenotype in both morphants. High T3 doses can partially revert the dominant negative action of mutant TRs in morphant fish. Therefore, our morphants recapitulate the RTHα and RTHβ key manifestations representing new models in which the functional consequences of human TR mutations can be rapidly and faithfully evaluated.