Programmed cell death protein 1 (PD-1), expressed on tumor-infiltrating T cells, is a T cell exhaustion marker. The mechanisms underlying PD-1 upregulation in CD4 T cells remain unknown. Here we develop nutrient-deprived media and a conditional knockout female mouse model to study the mechanism underlying PD-1 upregulation. Reduced methionine increases PD-1 expression on CD4 T cells. The genetic ablation of SLC43A2 in cancer cells restores methionine metabolism in CD4 T cells, increasing the intracellular levels of S-adenosylmethionine and yielding H3K79me2. Reduced H3K79me2 due to methionine deprivation downregulates AMPK, upregulates PD-1 expression and impairs antitumor immunity in CD4 T cells. Methionine supplementation restores H3K79 methylation and AMPK expression, lowering PD-1 levels. AMPK-deficient CD4 T cells exhibit increased endoplasmic reticulum stress and Xbp1s transcript levels. Our results demonstrate that AMPK is a methionine-dependent regulator of the epigenetic control of PD-1 expression in CD4 T cells, a metabolic checkpoint for CD4 T cell exhaustion.

Ouh YT, et al. J Gynecol Oncol. 2017 Sep;29(1):e14. https://doi.org/10.3802/jgo.2018.29.e14

Cervical cancer, primarily caused by high-risk human papillomavirus (HR-HPV) types 16 and 18, is a major global health concern. Persistent HR-HPV infection can progress from reversible precancerous lesions to invasive cervical cancer, which is driven by the oncogenic activity of human papillomavirus (HPV) genes, particularly E6 and E7. Traditional screening methods, including cytology and HPV testing, have limited sensitivity and specificity. This review explores the application of p16/Ki-67 dual-staining cytology for cervical cancer screening. This advanced immunocytochemical method allows for simultaneously detecting p16 and Ki-67 proteins within cervical epithelial cells, offering a more specific approach for triaging HPV-positive women. Dual staining and traditional methods are compared, demonstrating their high sensitivity and negative predictive value but low specificity. The increased sensitivity of dual staining results in higher detection rates of CIN2+ lesions, which is crucial for preventing cervical cancer progression. However, its low specificity may lead to increased false-positive results and unnecessary biopsies. The implications of integrating dual staining into contemporary screening strategies, particularly considering the evolving landscape of HPV vaccination and changes in HPV genotype prevalence, are also discussed. New guidelines and further research are necessary to elucidate the long-term effects of integrating dual staining into screening protocols.

Persistent infection of HPV increases the chance of carcinoma in situ of cervix through stages of cervical intraepithelial neoplasia (CIN) 1, 2, and 3, and finally progresses into cervical cancer. We aimed to explore the safety and efficacy of BLS-M07 which is orally administered agent expressing human papillomavirus (HPV) 16 E7 antigen on the surface of Lactobacillus casei in patients with CIN 3. Patients with CIN 3 were recruited in our clinical trial. Reid Colposcopic Index (RCI) grading and serum HPV16 E7 specific antibody production were used to evaluate efficacy of BLS-M07. In phase 1, BLS-M07 was administered orally, 5 times a week, on weeks 1, 2, 4, and 8 with dosages of 500 mg, 1,000 mg, and 1,500 mg. In phase 2a, patients were treated with 1,000 mg. The primary endpoints were the safety and the pathologic regression on colposcopic biopsy. Nineteen patients were enrolled in the CIN 3 cohort. In phase 1, no patients experienced dose limiting toxicity. No grade 3 or 4 treatment-related adverse events or deaths were observed. At 16 weeks after treatment, RCI grading was improved and serum HPV16 E7 specific antibody production increased (p<0.05). Six of 8 (75%) patients with CIN 3 were cured in phase 2a. Oral immunization with BLS-M07 increases production of serum HPV16 E7 specific antibody which induces protective humoral immunity. The safety of this oral vaccine was proved and could be a competitive non-surgical therapeutic agent of CIN 3. ClinicalTrials.gov Identifier: NCT02195089.

Ouh YT, et al. J Korean Med Sci. 2021 May;36(24):e164. https://doi.org/10.3346/jkms.2021.36.e164

Hong JH, et al. J Gynecol Oncol. 2022 Jan;33:e29. https://doi.org/10.3802/jgo.2022.33.e29