Dual Characters of GH-IGF1 Signaling Pathways in Radiotherapy and Post-radiotherapy Repair of Cancers

Experimental and network pharmacology certify itraconazole mitigates fluorouracil-induced intestinal damage by inhibiting mTOR-mediated intestinal senescence

Fluorouracil (Fu) is one of the first-line drugs for colorectal cancer, but severe intestinal damage limits its clinical application. The intestinal damage caused by Fu is closely related to cellular senescence. Itraconazole (Itr) is primarily used to treat fungal infections. At present, the effects of Itr on intestinal senescence and damage have not been the subject of extensive study. In this study, NCM460 cells were utilized to establish a model of Fu-induced senescence and inflammation. Treatment of NCM460 cells with Fu resulted in increased senescence-associated beta-galactosidase (SA-β-Gal) activity, elevated p21 expression, and the upregulation of p16 and p53. Additionally, there was enhanced Senescence-Associated Secretory Phenotype (SASP) and an increase in inflammatory factors IL-1β and IL-6. The present study demonstrated that the treatment of Itr effectively alleviated the changes caused by Fu in NCM460 cells. Moreover, it was observed that Itr was efficacious in mitigating intestinal damage induced by Fu in Balb/c mice. Network pharmacology analysis and experimental validation identified the mTOR signaling pathway as a key target of Itr in treating Fu-induced intestinal aging and inflammation. Our findings demonstrate that Itr significantly inhibited the mTOR pathway, while the mTOR activator MHY1485 restored mTOR activity and promoted senescence. Moreover, it was observed that Itr could effectively enhance the tumor-killing effect of Fu in HCT116 and SW480 cells, as well as in Balb/c nude mice. In conclusion, Itr is a promising candidate for reducing intestinal side effects and enhancing Fu's efficacy in the treatment of colorectal cancer.

TRIP13 protects pancreatic cancer cells against intrinsic and therapy-induced DNA replication stress

Oncogene activation in normal untransformed cells induces DNA replication stress and creates a dependency on DNA damage response (DDR) mechanisms for cell survival. Different oncogenic stimuli signal via distinct mechanisms in every cancer setting. The DDR is also pathologically reprogrammed and deployed in diverse ways in different cancers. Because mutant KRAS is the driver oncogene in 90% of pancreatic ductal adenocarcinomas (PDACs), here we have investigated DDR mechanisms by which KRAS-induced DNA replication stress is tolerated in normal human pancreatic epithelial cells [human pancreatic nestin-expressing (HPNE) cells]. Using a candidate screening approach, we identify TRIP13 as a KRASG12V-induced messenger RNA that is also expressed at high levels in PDAC relative to normal tissues. Using genetic and pharmacological tools, we show that TRIP13 is necessary to sustain ongoing DNA synthesis and viability specifically in KRASG12V-expressing cells. TRIP13 promotes survival of KRASG12V-expressing HPNE cells in a homologous recombination (HR)-dependent manner. KRASG12V-expressing HPNE cells lacking TRIP13 acquire hallmark HR deficiency phenotypes, including sensitivity to inhibitors of translesion synthesis and poly-ADP ribose polymerase. Established PDAC cell lines are also sensitized to intrinsic DNA damage and therapy-induced genotoxicity following TRIP13 depletion. Taken together, our results expose TRIP13 as an attractive new and therapeutically tractable vulnerability of KRAS-mutant PDAC.

TRIP13 protects pancreatic cancer cells against intrinsic and therapy-induced DNA replication stress

Oncogene activation in normal untransformed cells induces DNA replication stress and creates a dependency on DNA Damage Response (DDR) mechanisms for cell survival. Different oncogenic stimuli signal via distinct mechanisms in every cancer setting. The DDR is also pathologically re-programmed and deployed in diverse ways in different cancers. Because mutant KRAS is the driver oncogene in 90% of Pancreatic Ductal Adenocarcinomas (PDAC), here we have investigated DDR mechanisms by which KRAS-induced DNA replication stress is tolerated in normal human pancreatic epithelial cells (HPNE). Using a candidate screening approach, we identify TRIP13 as a KRASG12V-induced mRNA that is also expressed at high levels in PDAC relative to normal tissues. Using genetic and pharmacological tools, we show that TRIP13 is necessary to sustain ongoing DNA synthesis and viability specifically in KRASG12V-expressing cells. TRIP13 promotes survival of KRASG12V-expressing HPNE cells in a Homologous Recombination (HR)-dependent manner. KRASG12V-expressing HPNE cells lacking TRIP13 acquire hallmark HR-deficiency (HRD) phenotypes including sensitivity to inhibitors of Trans-Lesion Synthesis (TLS) and Poly-ADP Ribose Polymerase (PARP). Established PDAC cell lines are also sensitized to intrinsic DNA damage and therapy-induced genotoxicity following TRIP13-depletion. Taken together our results expose TRIP13 as an attractive new and therapeutically-tractable vulnerability of KRAS-mutant PDAC.

The protection role of human growth hormone on skin cells following ultraviolet B exposure

BACKGROUND

Ultraviolet-B (UVB) radiation is the leading environmental cause of skin damage and photoaging. The epidermis and dermis layers of the skin mainly absorb UVB. UVB stimulates apoptosis, cell cycle arrest, generation of reactive oxygen species, and degradation of collagen and elastin fibers.

OBJECTIVE

This study investigated the potential of human growth hormone (hGH) in protecting the skin fibroblasts and keratinocytes (HFFF-2 and HaCaT cell lines) from UVB-induced damage.

METHODS

The MTT assay was performed to evaluate UVB-induced mitochondrial damage via assessing the mitochondrial dehydrogenase activity, and flow cytometry was carried out to investigate the effects of UVB and hGH on the cell cycle and apoptosis of UVB-irradiated cells. In addition, the fold change mRNA expression levels of Type I collagen and elastin in HFFF-2 cells were evaluated using the qRT-PCR method following UVB exposure.

RESULTS

We observed that treatment of cells with hGH before UVB exposure inhibited UVB-induced loss of mitochondrial dehydrogenase activity, apoptosis, and sub-G1 population formation in both cell lines. We also found that hGH-treated HFFF-2 cells showed up-regulated mRNA expression of Type I collagen, elastin, and IGF-1 in response to UVB irradiation.

CONCLUSION

These findings suggest hGH as a potential anti-UVB compound that can protect skin cells from UVB-induced damage. Our findings merit further investigation and can be used to better understand the role of hGH in skin photoaging.

Growth hormone after CNS tumor diagnosis: the fundamentals, fears, facts, and future directions

Growth hormone deficiency (GHD) may occur in pediatric patients with central nervous system (CNS) tumors at initial tumor presentation or later as treatment-related sequelae. While it is well recognized that growth hormone (GH) has beneficial effects on growth and endocrinopathies, there's often hesitancy by clinicians to initiate GH therapy for GHD after CNS tumor diagnosis due to the perceived increased risk of tumor recurrence. The available data is described here and based on this review, there is no evidence of increased risk of tumor recurrence or secondary malignancy in patients treated with GH after CNS tumor diagnosis. Further understanding of tumor biology and presence of downstream GH targets including insulin-like growth factor-1 (IGF-1) and insulin receptor activity is still needed.