Targeting the crosstalk of epigenetic modifications and immune evasion in nasopharyngeal cancer

Nasopharyngeal carcinoma (NPC) is a distinct type of head and neck cancer that is highly associated with Epstein-Barr virus (EBV) infection. EBV acts as an epigenetic driver in NPC tumorigenesis, reprogramming the viral and host epigenomes to regulate viral latent gene expression, and creating an environment conducive to the malignant transformation of nasopharyngeal epithelial cells. Targeting epigenetic mechanisms in pre-clinical studies has been shown promise in eradicating tumours and overcoming immune resistance in some solid tumours. However, its efficacy in NPC remains inclusive due to the complex nature of this cancer. In this review, we provide an updated understanding of the roles of epigenetic factors in regulating EBV latent gene expression and promoting NPC progression. We also explore the crosstalk between epigenetic mechanisms and immune evasion in NPC. Particularly, we discuss the potential roles of DNA methyltransferase (DNMT) and histone deacetylase (HDAC) inhibitors in reversing immune suppression and augmenting antitumour immunity. Furthermore, we highlight the advantages of combining epigenetic therapy and immune checkpoint inhibitor to reverse immune resistance and improve clinical outcomes. Epigenetic drugs have the potential to modulate both epigenetic mediators and immune factors involved in NPC. However, further research is needed to fully comprehend the diverse range of epigenetic modifications in NPC. A deeper understanding of the crosstalk between epigenetic mechanisms and immune evasion during NPC progression is crucial for the development of more effective treatments for this challenging disease.

TP53 loss-of-function causes vulnerability to autophagy inhibition in aggressive prostate cancer

OBJECTIVES

TP53 loss-of-function is commonly found in aggressive prostate cancer. However, a highly-efficient therapy for this tumor subtype is still lacking. In this study, we investigated the relationship between TP53 mutation status and autophagy in prostate cancer and assessed the efficacy of autophagy inhibitors on TP53-deficient tumors.

METHODS

We first evaluated the expression patterns of p53 and autophagy-related proteins, namely LC3B, ULK1 and BECLIN1, as well as their relationship in treatment-naïve and castration-resistant prostate cancer specimens through immunohistochemistry. Subsequently, we generated a Trp53-deleted genetically-engineered mouse model, established prostate tumor organoid lines from the mice and assessed the efficacy of autophagy inhibitors in overcoming Enzalutamide resistance in the tumor organoid model. We also investigated the impact of TP53 re-expression in modulating responses to autophagy inhibitors using LNCaP cell line, which harbored a TP53 missense mutation. Lastly, we attempted to identify potential autophagy-related genes that were crucial for TP53-deficient tumor maintenance.

RESULTS

TP53 loss-of-function was associated with increased levels of autophagy-related proteins in aggressive prostate cancers and Trp53-deleted genetically-engineered mouse-derived tumors. Moreover, the generated androgen receptor-independent tumor organoids were highly vulnerable to autophagy inhibition. Upon TP53 re-expression, not only did the surviving LNCaP cells demonstrate resistance, but they also showed growth advantage in response to autophagy inhibition. Lastly, PEX14, an important peroxisomal regulator was differentially upregulated in aggressive tumors with TP53 loss-of-function mutations, thus implying the importance of peroxisome turnover in this tumor subtype.

CONCLUSION

Our results support the potential use of autophagy inhibitors in prostate cancers that contain TP53 loss-of-function mutations.

Modeling prostate cancer: What does it take to build an ideal tumor model?

Prostate cancer is frequently characterized as a multifocal disease with great intratumoral heterogeneity as well as a high propensity to metastasize to bone. Consequently, modeling prostate tumor has remained a challenging task for researchers in this field. In the past decades, genomic advances have led to the identification of key molecular alterations in prostate cancer. Moreover, resistance towards second-generation androgen-deprivation therapy, namely abiraterone and enzalutamide has unveiled androgen receptor-independent diseases with distinctive histopathological and clinical features. In this review, we have critically evaluated the commonly used preclinical models of prostate cancer with respect to their capability of recapitulating the key genomic alterations, histopathological features and bone metastatic potential of human prostate tumors. In addition, we have also discussed the potential use of the emerging organoid models in prostate cancer research, which possess clear advantages over the commonly used preclinical tumor models. We anticipate that no single model can faithfully recapitulate the complexity of prostate cancer, and thus, propose the use of a cost- and time-efficient integrated tumor modeling approach for future prostate cancer investigations.

Iron-Binding Capacity of Defatted Rice Bran Hydrolysate and Bioavailability of Iron in Caco-2 Cells

The present study was aimed at utilizing defatted rice bran (DRB) protein as an iron-binding peptide to enhance iron uptake in humans. DRB samples were treated with Alcalase and Flavourzyme, and the total extractable peptides were determined. Furthermore, the iron-binding capacities of the DRB protein hydrolysates were determined, whereas iron bioavailability studies were conducted using an in vitro digestion and absorption model (Caco-2 cells). The results showed that the DRB protein hydrolysates produced by combined Alcalase and Flavourzyme hydrolysis had the best iron-binding capacity (83%) after 90 min of hydrolysis. The optimal hydrolysis time to produce the best iron-uptake in Caco-2 cells was found to be 180 min. The results suggested that DRB protein hydrolysates have potent iron-binding capacities and may enhance the bioavailability of iron, hence their suitability for use as iron-fortified supplements.

Microvascular changes in the peripheral microcirculation of women with chronic pelvic pain due to congestion

OBJECTIVE

Pelvic venous congestion is a common finding in women with chronic pelvic pain. While the pathophysiology of this condition is poorly understood, there are clear indications that it involves vascular dysfunction. The present studies sought abnormalities in microvascular function in these patients.

DESIGN

Prospective longitudinal study.

SETTING

A teaching hospital tertiary referral.

POPULATION

Eighteen women with pelvic congestion and 13 normal women.

METHODS

Parameters of microcirculatory function were measured in the calves of women using venous congestion plethysmography during the midfollicular and midluteal phases of the menstrual cycle. The women with pelvic congestion were studied again after treatment for the condition.

MAIN OUTCOME MEASURES

Isovolumetric venous pressure, microvascular filtration capacity and limb blood flow.

RESULTS

Of the measured parameters of microvascular function, only isovolumetric venous pressure (Pvi) was significantly higher in women with congestion when compared to the controls during the same phase of the cycle. There were no menstrual cycle related differences in any of the other measured parameters in either patients or controls. Following successful treatment for the condition, values of Pvi in women with pelvic congestion were significantly reduced, achieving a level similar to that observed in the controls.

CONCLUSION

The observed changes in Pvi suggest that this parameter is intimately associated with the pathophysiology of pelvic congestion. The increase in Pvi, without alterations in other measured microvascular parameters, may be attributable to systemic increases in postcapillary resistance secondary to neutrophil activation. These findings support the notion of systemic microvascular dysfunction in these women.

The effects of 1.5T magnetic resonance imaging on early murine in-vitro embryo development

Although no ionizing radiation is involved, patients undergoing magnetic resonance imaging (MRI) are exposed to powerful static magnetic fields, magnetic field gradients, and radio-frequency fields that may be potentially damaging. Our study aims to document the effect of MRI imaging sequences on early murine embryo development (two-cell to blastocyst stage) in vitro. Two-cell murine embryos were exposed to various lengths of MRI using pulse sequences employed in present day clinical imaging. Early murine embryo development was documented in vitro, and blastocyst development rates were computed for both the control and exposed groups. There were no significant differences detected in the rate of blastocyst formation between the control groups and the embryos exposed to MRI.

Membrane sweeping in conjunction with labor induction

OBJECTIVE

To determine whether cervical membrane sweeping (stripping) during induction of labor is beneficial.

METHODS

We compared outcomes of labor after induction in pregnant women at term in a randomized trial. Women were assigned to having their membranes swept or not during induction. Outcome measures included duration of labor, maximum dose of oxytocin used, induction-labor interval, and mode of delivery.

RESULTS

We recruited 130 nulliparas (64 sweep, 66 nonsweep) and 118 multiparas (60 sweep, 58 nonsweep). Among nulliparas who received intravaginal prostaglandin (PG) E(2) and oxytocin, those who had simultaneous sweeping had significantly shorter mean (+/- standard error of mean) induction-labor interval (13.6 +/- 1.4 versus 17.3 +/- 1.2 hours, P =.048), lower mean maximum dose of oxytocin (6.8 +/- 0.8 versus 10.35 +/- 1.1 mU/minute, P =.01), and increased normal delivery rates (vaginal delivery 83. 3% versus 58.2%, P =.01). Sweeping also had a favorable effect on nulliparas who received oxytocin alone (mean induction-labor interval 5.8 +/- 3.1 versus 11.2 +/- 3.6 hours, P =.04; mean maximum dose 8.8 +/- 1.3 versus 16.3 +/- 1.9 mU/min, P =.01). Those differences were limited to women with unfavorable cervices. There were no differences in any outcome measures in multiparous women.

CONCLUSION

Sweeping of the membranes during induction of labor had a beneficial effect on labor and delivery, which appeared to be limited to nulliparas with unfavorable cervices who needed cervical priming with PGE(2).

Impaired vasoconstriction in pregnancy-induced hypertension assessed using doppler fluximetry

OBJECTIVE

To determine whether there is a difference in peripheral vascular reactivity between normal women and those with pregnancy-induced hypertension.

METHODS

Capillary blood flow (flux) was recorded in the skin over the ankle in 26 pregnant women with pregnancy-induced hypertension at term. Twelve of these women had proteinuria, and 14 were nonproteinuric. Leg lowering was used to activate the venoarteriolar reflex, and the resultant change in flux, expressed as a percentage change from the baseline, was used as an index of vascular reactivity. The results were compared with those of a control group comprising 23 matched normotensive women. The study was repeated on all of the women after delivery.

RESULTS

Women with hypertension showed a median (range) increase in flux of +24.4% (-15.5% to +151.1%), significantly different from controls: -39.3% (-80.9% to -4.3%, P <.001). This difference persisted regardless of the presence or absence of proteinuria. Responses in women with pregnancy-induced hypertension were significantly different after delivery (median -60.7%; range -158.5% to -19.5%, P <.001) when compared with predelivery responses. Similar changes as a result of delivery were seen in women with proteinuric (medians +25.9% and -57. 9%, P <.002) and nonproteinuric (medians +7.8% and -62.8%, P <.001) hypertension but not in controls. Postdelivery responses in women with hypertension were no different from those of controls.

CONCLUSION

Women with pregnancy-induced hypertension have abnormal cutaneous vascular reactivity that returns to normal after delivery.

Altered peripheral vascular response of women with and without pelvic pain due to congestion

OBJECTIVE

To test the hypothesis that women with pelvic venous congestion have a reduction of reactivity of their peripheral circulation.

DESIGN

Comparison was made between 20 women with chronic pelvic pain due to congestion and a control group of 15 pain-free women matched for age, parity and body weight. A comparison of these results was made with those from six postmenopausal women taking hormone replacement therapy.

METHODS

Study and control groups were investigated during the mid-follicular phase of the menstrual cycle (days 5-9) and the mid-luteal phase (days 19-23). The study group was also investigated during the fifth month of treatment with suppression of ovarian activity with leuprorelin or medroxyprogesterone acetate or six months after hysterectomy and bilateral salpingo-oophorectomy. Head-up tilt sufficient to increase intra-vascular pressure in the toe by a standard 40 mmHg was used as a means of raising venous pressure in the lower limb. Skin capillary red blood cell velocity (flux) was measured using a laser Doppler flow probe placed over the pulp of the big toe. Heart rate and blood pressure were also recorded. The change in skin blood flow following head-up tilt was expressed as a percentage of baseline flow in the supine position.

MAIN OUTCOME MEASURES

Percentage change in skin red blood cell flux, heart rate and blood pressure in response to 40 degrees head-up tilt.

RESULTS

In the control group the median response to head-up tilt in the follicular phase was one of a reduction in flux, whereas in the luteal phase it was more variable ranging from an increase to a decrease in flux. The responses in the pelvic congestion group in both the follicular and luteal phases were similar to those of the control group in the luteal phase. A small but significant increase in heart rate in response to tilt in the pelvic pain group, compared with the control group, was interpreted as being due to a fall in venous return. Treatment of the pelvic congestion group by medical suppression of ovarian activity or total hysterectomy with bilateral salpingo-oophorectomy resulted in a significant change in response to head-up tilt from the variable type of luteal response to one of a more constant reduction in flux, similar to that of the control group in the follicular phase. A reduction in flux was also found consistently in postmenopausal women.

CONCLUSION

The study confirms the hypothesis that women with pelvic pain due to congestion show a change in peripheral vascular reactivity which returns to normal after suppression of ovarian activity. It seems likely that some alteration of normal ovarian function is responsible for the observed changes in peripheral blood flow in response to a rise in venous pressure in women with pelvic congestion.

Assisted reproductive techniques--promises and problems

Assisted reproductive techniques (ART) are procedures in which the oocyte is handled before replacement, either as an oocyte or embryo. The current success rates and pregnancy outcomes of in-vitro fertilisation (IVF), gamete intra-fallopian transfer (GIFT), zygote intra-fallopian transfer (ZIFT), intra-cytoplasmic sperm injection (ICSI), donor oocyte and frozen embryo programmes are reviewed. Some problems associated with assisted reproductive procedures are also discussed.