In light of the burgeoning successes of cancer immunotherapy, glioblastoma (GBM) remains refractory due to an immunosuppressive microenvironment originating from its molecular heterogeneity. Thus, identifying promising therapeutic targets for treating GBM and discovering methodologies to effectively regulate them is still a tremendous challenge. Here we describe photodynamic protein tyrosine phosphatase 1B (PTP1B) proteolysis mediated by a proteolysis-targeting chimera (PROTAC) nanoassembly. The PTP1B-targeting PROTAC is conjugated with a photosensitizer via a cathepsin B (Cat B)-cleavable peptide, which spontaneously forms nanoassemblies due to intermolecular π-π stacking interactions. In GBM models, PROTAC nanoassemblies significantly accumulate in the tumor region across the disrupted blood-brain barrier (BBB), triggering a burst release of the photosensitizer and active PROTAC by Cat B-mediated enzymatic cleavage. Upon laser irradiation, photodynamic therapy (PDT) synergizes with PROTAC-mediated PTP1B proteolysis to induce potent immunogenic cell death (ICD) in tumor cells. Subsequently, persistent PTP1B degradation by nanoassemblies in Cat B-overexpressed intratumoral T cells downregulates exhaustion markers, reinvigorating their functionality. These sequential processes of photodynamic PTP1B proteolysis ultimately augment T cell-mediated antitumor immunity as well as protective immunity, completely eradicating the primary GBM and preventing its recurrence. Overall, our findings underscore the therapeutic potential of combining PDT with PROTAC activity for GBM immunotherapy.

Aging is defined as physiological dysfunction of the body and a key risk factor for human diseases. During the aging process, cellular senescence occurs in response to various extrinsic and intrinsic factors such as radiation-induced DNA damage, the activation of oncogenes, and oxidative stress. These senescent cells accumulate in many tissues and exhibit diverse phenotypes, such as resistance to apoptosis, production of senescence-associated secretory phenotype, cellular flattening, and cellular hypertrophy. They also induce abnormal dysfunction of the microenvironment and damage neighboring cells, eventually causing harmful effects in the development of various chronic diseases such as diabetes, cancer, and neurodegenerative diseases. Thus, pharmacological interventions targeting senescent cells, called senotherapeutics, have been extensively studied. These senotherapeutics provide a novel strategy for extending the health span and improving age-related diseases. In this review, we discuss the current progress in understanding the molecular mechanisms of senotherapeutics and provide insights for developing senotherapeutics.

We investigated the effect of alpha-subunit of the stimulatory GTP-binding protein (Galphas) gene mutation on the expression of the thyrotropin-releasing hormone (TRH) receptor (TRH-R) gene in GH3 cells and in growth hormone (GH)-secreting adenomas of acromegalic patients. In the presence of cycloheximide, forskolin and isobutylmethylxanthine, cholera toxin, and GH-releasing hormone (GBRH) decreased rat TRH-R (rTRH-R) gene expression by about 39%, 43.7%, and 46.7%, respectively. Transient expression of a vector expressing mutant-type Galphas decreased the rTRH-R gene expression by about 50% at 24 h of transfection, whereas a wild-type Galphas expression vector did not. The transcript of human TRH-R (hTRH-R) gene was detected in 6 of 8 (75%) tumors. Three of them (50%) showed the paradoxical GH response to TRH and the other three patients did not show the response. The relative expression of hTRH-R mRNA in the tumors from patients with the paradoxical response of GH to TRH did not differ from that in the tumors from patients without the paradoxical response. Direct PCR sequencing of GALPHAs gene disclosed a mutant allele and a normal allele only at codon 201 in 4 of 8 tumors. The paradoxical response to TRH was observed in 2 of 4 patients without the mutation, and 2 of 4 patients with the mutation. The hTRH-R gene expression of pituitary adenomas did not differ between the tumors without the mutation and those with mutation. The present study suggests that the expression of TRH-R gene is not likely to be a main determinant for the paradoxical response of GH to TRH, and that Galphas mutation may suppress the gene expression of TRH-R in GH-secreting adenoma. However, a certain predisposing factor(s) may play an important role in determining the expression of TRH-R.
Acromegaly ; Adenoma ; Alleles ; Animals ; Cholera Toxin ; Codon ; Colforsin ; Cycloheximide ; Gene Expression ; Growth Hormone ; GTP-Binding Proteins ; Humans ; Pituitary Neoplasms ; Polymerase Chain Reaction ; Rats ; Receptors, Thyrotropin-Releasing Hormone* ; RNA, Messenger* ; Thyrotropin-Releasing Hormone ; Transfection