Long-term follow-up of efficacy and safety of selinexor maintenance treatment in patients with TP53wt advanced or recurrent endometrial cancer: A subgroup analysis of the ENGOT-EN5/GOG-3055/SIENDO study.

OBJECTIVE: To report long-term efficacy and safety of selinexor maintenance therapy in adults with TP53 wild-type (TP53wt) stage IV or recurrent endometrial cancer (EC) who achieved partial remission (PR) or complete remission (CR) following chemotherapy. METHODS: Analysis of the prespecified, exploratory subgroup of patients with TP53wt EC from the phase 3 SIENDO study was performed. Progression-free survival (PFS) benefit in patients with TP53wt EC and across other patient subgroups were exploratory endpoints. Safety and tolerability were also assessed. RESULTS: Of the 263 patients enrolled in the SIENDO trial, 113 patients had TP53wt EC; 70/113 (61.9%) had TP53wt/proficient mismatch repair (pMMR) EC, and 29/113 (25.7%) had TP53wt/deficient mismatch repair (dMMR) EC. As of April 1, 2024, the median PFS (mPFS) for TP53wt patients who received selinexor compared with placebo was 28.4 versus 5.2 months (36.8-month follow-up, HR 0.44; 95% CI 0.27-0.73). A benefit in mPFS was seen with selinexor versus placebo regardless of MMR status (patients with TP53wt/pMMR EC: 39.5 vs 4.9 months, HR 0.36; 95% CI 0.19-0.71; patients with TP53wt/dMMR EC: 13.1 vs 3.7 months, HR 0.49; 95% CI 0.18-1.34). Selinexor treatment was generally manageable, with no new safety signals identified. CONCLUSION: In the phase 3 SIENDO study, selinexor maintenance therapy showed a promising efficacy signal and a manageable safety profile in the prespecified subgroup of patients with TP53wt EC who achieved a PR or CR following chemotherapy. These results are being further evaluated in an ongoing randomized phase 3 trial (NCT05611931).

p53 missense mutant G242A subverts natural killer cells in sheltering mouse breast cancer cells against immune rejection.

Cancer cells acquire immunoediting ability to evade immune surveillance and thus escape eradication. It is widely known that mutant proteins encoded from tumor suppressor TP53 exhibit gain-of-function in cancer cells, thereby promoting progression; however, how mutant p53 contributes to the sheltering of cancer cells from host anticancer immunity remains unclear. Herein, we report that murine p53 missense mutation G242A (corresponding to human G245A) suppresses the activation of host natural killer (NK) cells, thereby enabling breast cancer cells to avoid immune assault. We found that serial injection of EMT6 breast cancer cells that carry wild-type (wt) Trp53, like normal fibroblasts, promoted NK activity in mice, while SVTneg2 cells carrying Trp53 G242A+/+ mutation decreased NK cell numbers and increased CD8+ T lymphocyte numbers in spleen. Innate immunity based on NK cells and CD8 T cells was reduced in p53 mutant-carrying transgenic mice (Trp53 R172H/+, corresponding to human R175H/+). Further, upon co-culture with isolated NK cells, EMT6 cells substantively activated NK cells and proliferation thereof, increasing interferon-gamma (IFN-γ) production; however, SVTneg2 cells suppressed NK cell activation. Further mechanistic study elucidated that p53 can modulate expression by cancer cells of Mult-1 and H60a, which are activating and inhibitory ligands for NKG2D receptors of NK cells, respectively, to enhance immune surveillance against cancer. Our findings demonstrate that wt p53 is requisite for NK cell-based immune recognition and elimination of cancerous cells, and perhaps more importantly, that p53 missense mutant presence in cancer cells impairs NK cell-attributable responses, thus veiling cancerous cells from host immunity and enabling cancer progression.

PCNA-associated factor (KIAA0101/PCLAF) overexpression and gene copy number alterations in hepatocellular carcinoma tissues.

BACKGROUND: PCNA-associated factor, the protein encoded by the KIAA0101/PCLAF gene, is a cell-cycle regulated oncoprotein that regulates DNA synthesis, maintenance of DNA methylation, and DNA-damage bypass, through the interaction with the human sliding clamp PCNA. KIAA0101/PCLAF is overexpressed in various cancers, including hepatocellular carcinoma (HCC). However, it remains unknown whether KIAA0101/PCLAF overexpression is coupled to gene amplification in HCC. METHODS: KIAA0101/PCLAF mRNA expression levels were assessed by quantitative real-time PCR (qRT-PCR) in 40 pairs of snap-frozen HCC and matched-non-cancerous tissues. KIAA0101/PCLAF gene copy numbers were evaluated by droplet digital PCR (ddPCR) in 36 pairs of the tissues, and protein expression was detected by immunohistochemistry (IHC) in 81 pairs of formalin-fixed paraffin-embedded (FFPE) tissues. The KIAA0101/PCLAF gene copy number alteration and RNA expression was compared by Spearman correlation. The relationships between KIAA0101 protein expression and other clinicopathological parameters, including Ki-67, p53, and HBsAg protein expression in HCC tissues, were evaluated using Chi-square test. RESULTS: Our results demonstrated that KIAA0101/PCLAF mRNA levels were significantly higher in HCC than in the matched-non-cancerous tissues (p < 0.0001). The high KIAA0101/PCLAF mRNA levels in HCC were associated with poor patient survival. The KIAA0101/PCLAF gene was not amplified in HCC, and KIAA0101/PCLAF gene copy numbers were not associated with KIAA0101/PCLAF transcript levels. KIAA0101 protein was overexpressed in the majority of HCC tissues (77.8%) but was not detectable in matched-non-cancerous tissues. Significant correlations between the expression of KIAA0101 protein in HCC tissues and p53 tumor suppressor protein (p = 0.002) and Ki-67 proliferation marker protein (p = 0.017) were found. However, KIAA0101 protein levels in HCC tissues were not correlated with patient age, tumor size, serum AFP level, or the HBsAg expression. CONCLUSIONS: KIAA0101/PCLAF mRNA and protein overexpression is frequently observed in HCC but without concurrent KIAA0101/PCLAF gene amplification. Significant correlations between the expression of KIAA0101 protein and p53 and Ki-67 proteins were observed in this study. Thus, detection of KIAA0101/PCLAF mRNA/protein might be used, along with the detection of p53 and Ki-67 proteins, as potential biomarkers to select candidate patients for further studies of novel HCC treatment related to these targets.

O6-methylguanine-induced transcriptional mutagenesis reduces p53 tumor-suppressor function.

Altered protein function due to mutagenesis plays an important role in disease development. This is perhaps most evident in tumorigenesis and the associated loss or gain of function of tumor-suppressor genes and oncogenes. The extent to which lesion-induced transcriptional mutagenesis (TM) influences protein function and its contribution to the development of disease is not well understood. In this study, the impact of O6-methylguanine on the transcription fidelity of p53 and the subsequent effects on the protein's function as a regulator of cell death and cell-cycle arrest were examined in human cells. Levels of TM were determined by RNA-sequencing. In cells with active DNA repair, misincorporation of uridine opposite the lesion occurred in 0.14% of the transcripts and increased to 14.7% when repair by alkylguanine-DNA alkyltransferase was compromised. Expression of the dominant-negative p53 R248W mutant due to TM significantly reduced the transactivation of several established p53 target genes that mediate the tumor-suppressor function, including CDKN1A (p21) and BBC3 (PUMA). This resulted in deregulated signaling through the retinoblastoma protein and loss of G1/S cell-cycle checkpoint function. In addition, we observed impaired activation of apoptosis coupled to the reduction of the tumor-suppressor functions of p53. Taking these findings together, this work provides evidence that TM can induce phenotypic changes in mammalian cells that have important implications for the role of TM in tumorigenesis.

Expression and clinicopathological significance of lipin-1 in human breast cancer and its association with p53 tumor suppressor gene.

Breast cancer (BC) is an important cause of female cancer-related death. It has recently been demonstrated that metabolic disorders including lipid metabolism are a hallmark of cancer cells. Lipin-1 is an enzyme that displays phosphatidate phosphatase activity and regulates the rate-limiting step in the pathway of triglycerides and phospholipids synthesis. The objective of this study was to evaluate lipin-1 expression, its prognostic significance, and its correlation with p53 tumor suppressor in patients with BC. In this study, 55 pairs of fresh samples of BC and adjacent noncancerous tissue were used to analyze lipin-1, using quantitative real-time polymerase chain reaction and immunohistochemistry (IHC) staining. The expression of other clinicopathological variables and p53 was also examined using IHC technique. The cell migration was studied in MCF-7 and MDA-MB231 cells following the inhibition of lipin-1 by propranolol. Our results show that the relative expression of lipin-1 messenger RNA was significantly higher in BC tissues compared with the adjacent normal tissue and its inhibition reduced cell migration in cancer cells. This upregulation was negatively correlated with histological grade of tumor and p53 status (p = .001 and p = .034) respectively and positively correlated with the tumor size (p = .006). Our results also seem to indicate that the high lipin-1 expression is related to a good prognosis in patients with BC. The expression of lipin-1 may be considered as a novel independent prognostic factor. The inhibition of lipin-1 may also have therapeutic significance for patients with BC. The correlation between lipin-1 and p53 confirms the role of p53 in the regulation of lipid metabolism in cancer cells.

Influence of Tumor Suppressor p53 Functioning on the Expression of Antioxidant System Genes under the Action of Cytotoxic Compounds.

The effect of inhibition of the tumor suppressor p53 on the antioxidant system genes expression under the influence of cytotoxic compounds of the platinum group was studied. It was found that the action of platinum(II) and platinum(IV) complexes induced accumulation of p53 protein with a maximum in 12 h, which was confirmed by an increase in the expression of the P21 gene, the target gene of the p53 protein. It was shown that the action of platinum complexes activated the expression of catalase and superoxide dismutase 2 genes. Suppression of p53 protein functions with specific inhibitor α-piphitrin under the action of platinum complexes reduced the expression of catalase and superoxide dismutase 2 genes and the target gene P21, which attested to the p53-dependent regulation of these genes.

p53-competent cells and p53-deficient cells display different susceptibility to oxygen functionalized graphene cytotoxicity and genotoxicity.

Due to the distinctive physical, electrical, and chemical properties of graphene nanomaterials, numerous efforts pursuing graphene-based biomedical and industrial applications are underway. Oxidation of pristine graphene surfaces mitigates its otherwise hydrophobic characteristic thereby improving its biocompatibility and functionality. Yet, the potential widespread use of oxidized graphene derivatives raises concern about adverse impacts on human health. The p53 tumor suppressor protein maintains cellular and genetic stability after toxic exposures. Here, we show that p53 functional status correlates with oxygen functionalized graphene (f-G) cytotoxicity and genotoxicity in vitro. The f-G exposed p53-competent cells, but not p53-deficient cells, initiated G0 /G1 phase cell cycle arrest, suppressed reactive oxygen species, and entered apoptosis. There was p53-dependent f-G genotoxicity evident as increased structural chromosome damage, but not increased gene mutation or chromatin loss. In conclusion, the cytotoxic and genotoxic potential for f-G in exposed cells was dependent on the p53 functional status. These findings have broad implications for the safe and effective implementation of oxidized graphene derivatives into biomedical and industrial applications. Published 2017. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Essential Roles of E3 Ubiquitin Ligases in p53 Regulation.

The ubiquitination pathway and proteasomal degradation machinery dominantly regulate p53 tumor suppressor protein stability, localization, and functions in both normal and cancerous cells. Selective E3 ubiquitin ligases dominantly regulate protein levels and activities of p53 in a large range of physiological conditions and in response to cellular changes induced by exogenous and endogenous stresses. The regulation of p53's functions by E3 ubiquitin ligases is a complex process that can lead to positive or negative regulation of p53 protein in a context- and cell type-dependent manner. Accessory proteins bind and modulate E3 ubiquitin ligases, adding yet another layer of regulatory control for p53 and its downstream functions. This review provides a comprehensive understanding of p53 regulation by selective E3 ubiquitin ligases and their potential to be considered as a new class of biomarkers and therapeutic targets in diverse types of cancers.

JMJD5 interacts with p53 and negatively regulates p53 function in control of cell cycle and proliferation.

JMJD5 is a Jumonji C domain-containing demethylase/hydroxylase shown to be essential in embryological development, osteoclastic maturation, circadian rhythm regulation and cancer metabolism. However, its role and underlying mechanisms in oncogenesis remain unclear. Here, we demonstrate that JMJD5 forms complex with the tumor suppressor p53 by interacting with p53 DNA-binding domain (DBD), and negatively regulates its activity. Downregulation of JMJD5 resulted in increased expression of multiple p53 downstream genes, such as the cell cycle inhibitor CDKN1A and DNA repair effector P53R2, only in p53-proficient lung cancer cells. Upon DNA damage, the JMJD5-p53 association decreased, and thereby, promoted p53 recruitment to the target genes and stimulated its transcriptional activity. Furthermore, JMJD5 facilitated the cell cycle progression in a p53-dependent manner under both normal and DNA damage conditions. Depletion of JMJD5 inhibited cell proliferation and enhanced adriamycin-induced cell growth suppression in the presence of p53. Collectively, our results reveal that JMJD5 is a novel binding partner of p53 and it functions as a positive modulator of cell cycle and cell proliferation mainly through the repression of p53 pathway. Our study extends the mechanistic understanding of JMJD5 function in cancer development and implicates JMJD5 as a potential therapeutic target for cancer.

Negative regulation of p53 by Ras superfamily protein RBEL1A.

We had previously reported that RBEL1A, a novel Ras-like GTPase, was overexpressed in multiple human malignancies and that its depletion suppressed cell growth. However, the underlying molecular mechanism remained to be elucidated. Here we report that depletion of endogenous RBEL1A results in p53 accumulation due to increased p53 half-life whereas increased expression of RBEL1A reduces p53 levels under unstressed and genotoxic stress conditions. RBEL1A directly interacts with p53 and MDM2, and strongly enhances MDM2-dependent p53 ubiquitylation and degradation. We also found that RBEL1A modulation of p53 ubiquitylation by MDM2 does not depend on its GTPase activity. We have also defined the p53 oligomeric domain and RBEL1A GTPase domain to be the crucial regions for p53-RBEL1A interactions. Importantly, we have found that RBEL1A strongly interferes with p53 transactivation function; thus our results indicate that RBEL1A appears to function as a novel p53 negative regulator that facilitates MDM2-dependent p53 ubiquitylation and degradation.

Distinct genomic and immunologic tumor evolution in germline TP53-driven breast cancers.

Pathogenic germline TP53 alterations cause Li-Fraumeni Syndrome (LFS), and breast cancer is the most common cancer in LFS females. We performed first of its kind multimodal analysis of LFS breast cancer (LFS-BC) compared to sporadic premenopausal BC. Nearly all LFS-BC underwent biallelic loss of TP53 with no recurrent oncogenic variants except ERBB2 (HER2) amplification. Compared to sporadic BC, in situ and invasive LFS-BC exhibited a high burden of short amplified aneuploid segments (SAAS). Pro-apoptotic p53 target genes BAX and TP53I3 failed to be up-regulated in LFS-BC as was seen in sporadic BC compared to normal breast tissue. LFS-BC had lower CD8+ T-cell infiltration compared to sporadic BC yet higher levels of proliferating cytotoxic T-cells. Within LFS-BC, progression from in situ to invasive BC was marked by an increase in chromosomal instability with a decrease in proliferating cytotoxic T-cells. Our study uncovers critical events in mutant p53-driven tumorigenesis in breast tissue.

Coagulation factor V in breast cancer: a p53-regulated tumor suppressor and predictive marker for treatment response to chemotherapy.

BACKGROUND: Patients with cancer are at an increased risk of developing coagulation complications, and chemotherapy treatment increases the risk. Tumor progression is closely linked to the hemostatic system. Breast cancer tumors express coagulation factor V (FV), an essential factor in blood coagulation. The functional role of FV during treatment with chemotherapy is poorly understood and was explored in this study. OBJECTIVES: We aimed to investigate the role of FV in breast cancer progression by exploring associations with treatment response, gene regulation, and the functional effects of FV. METHODS: The receiver operating characteristic plotter was used to explore the predictive value of FV mRNA (F5) expression for treatment with FEC (5-fluorouracil, anthracycline, and cyclophosphamide). Breast cancer cohorts were analyzed to study treatment response to FEC. The effect of chemotherapy on F5 expression, the regulation of F5, and the functional effects of FV dependent and independent of chemotherapy were studied in breast cancer cell lines. RESULTS: F5 tumor expression was significantly higher in responders to FEC than in nonresponders. In vitro experiments revealed that anthracycline treatment increased the expression of F5. Inhibition and knockdown of p53 reduced the anthracycline-induced F5 expression. Mutation of a p53 half-site (c.158+1541/158+1564) in a luciferase plasmid reduced luciferase activity, suggesting that p53 plays a role in regulating F5. FV overexpression increased apoptosis and reduced proliferation slightly during anthracycline treatment. CONCLUSION: Our study identified F5 as a p53-regulated tumor suppressor candidate and a promising marker for response to chemotherapy. FV may have functional effects that are therapeutically relevant in breast cancer.

Analysis of TP53 mutation spectra reveals the fingerprint of the potent environmental carcinogen, aristolochic acid.

Genetic alterations in cancer tissues may reflect the mutational fingerprint of environmental carcinogens. Here we review the pieces of evidence that support the role of aristolochic acid (AA) in inducing a mutational fingerprint in the tumor suppressor gene TP53 in urothelial carcinomas of the upper urinary tract (UUT). Exposure to AA, a nitrophenathrene carboxylic acid present in certain herbal remedies and in flour prepared from wheat grain contaminated with seeds of Aristolochia clematitis, has been linked to chronic nephropathy and UUT. TP53 mutations in UUT of individuals exposed to AA reveal a unique pattern of mutations characterized by A to T transversions on the non-transcribed strand, which cluster at hotspots rarely mutated in other cancers. This unusual pattern, originally discovered in UUTs from two different populations, one in Taiwan, and one in the Balkans, has been reproduced experimentally by treating mouse cells that harbor human TP53 sequences with AA. The convergence of molecular epidemiological and experimental data establishes a clear causal association between exposure to the human carcinogen AA and UUT. Despite bans on the sale of herbs containing AA, their use continues, raising global public health concern and an urgent need to identify populations at risk.

Cholesterol esterification and p53-mediated tumor suppression.

Many human cancers carry missense mutations in or deletions of the tumor protein 53 (TP53) tumor suppressor gene. TP53's product, p53 regulates many biological processes, including cell metabolism. Cholesterol is a key lipid needed for the maintenance of membrane function and tissue homeostasis while also serving as a precursor for steroid hormone and bile acid synthesis. An over-abundance of cholesterol can lead to its esterification and storage as cholesterol esters. The recent study has shown that the loss of p53 leads to excessive cholesterol ester biosynthesis, which promotes hepatocellular carcinoma in mice. Blocking cholesterol esterification improves treatment outcomes, particularly for liver cancers with p53 deletions/mutations that originate in a background of non-alcoholic fatty liver disease.

Wild-type and mutant p53 in cancer-related ferroptosis. A matter of stress management?

Cancer cells within tumor masses are chronically exposed to stress caused by nutrient deprivation, oxygen limitation, and high metabolic demand. They also accumulate hundreds of mutations, potentially generating aberrant proteins that can induce proteotoxic stress. Finally, cancer cells are exposed to various damages during chemotherapy. In a growing tumor, transformed cells eventually adapt to these conditions, eluding the death-inducing outcomes of signaling cascades triggered by chronic stress. One such extreme outcome is ferroptosis, a form of iron-dependent non-apoptotic cell death mediated by lipid peroxidation. Not surprisingly, the tumor suppressor p53 is involved in this process, with evidence suggesting that it acts as a pro-ferroptotic factor and that its ferroptosis-inducing activity may be relevant for tumor suppression. Missense alterations of the TP53 gene are extremely frequent in human cancers and give rise to mutant p53 proteins (mutp53) that lose tumor suppressive function and can acquire powerful oncogenic activities. This suggests that p53 mutation provides a selective advantage during tumor progression, raising interesting questions on the impact of p53 mutant proteins in modulating the ferroptotic process. Here, we explore the role of p53 and its cancer-related mutants in ferroptosis, using a perspective centered on the resistance/sensitivity of cancer cells to exogenous and endogenous stress conditions that can trigger ferroptotic cell death. We speculate that an accurate molecular understanding of this particular axis may improve cancer treatment options.

Transformed cells after senescence give rise to more severe tumor phenotypes than transformed non-senescent cells.

Oncogenic stress-induced senescence initially inhibits tumor initiation by blocking proliferation and by attracting immune cells to clear potentially harmful cells. If these cells are not eliminated they may resume proliferation upon loss-of-tumor suppressors, and be at risk of transformation. During tumor formation, depending on the sequence of events of gain-of-oncogenes and/or loss-of-tumor suppressors, cancer cells may emerge from senescent cells. Here, we show that these transformed cells after senescence (TS) display more aggressive tumorigenic features, with a greater capacity to migrate and a higher resistance to anti-tumoral drugs than cells having undergone transformation without senescence. Bulk transcriptomic analysis and single cell RNA sequencing revealed a signature unique to TS cells. A score of this signature was then generated and a high score was correlated with decreased survival of patients with lung adenocarcinoma, head-neck squamous cell carcinoma, adrenocortical carcinoma, liver hepatocellular carcinoma, skin cutaneous melanoma and low-grade glioma. Together, these findings strongly support that cancer cells arising from senescent cells are more dangerous, and that a molecular signature of these cells may be of prognostic value for some human cancers. It also raises questions about modeling human tumors, using cells or mice, without regards to the sequence of events leading to transformation.

Butyrate supplementation regulates expression of chromosome segregation 1­like protein to reverse the genetic distortion caused by p53 mutations in colorectal cancer.

The chromosome segregation 1­like (CSE1L) protein, which regulates cellular mitosis and apoptosis, was previously found to be overexpressed in colorectal cancer (CRC) cells harboring mutations. Therefore, regulating CSE1L expression may confer chemotherapeutic effects against CRC. The gut microflora can regulate gene expression in colonic cells. In particular, metabolites produced by the gut microflora, including the short­chain fatty acid butyrate, have been shown to reduce CRC risk. Butyrates may exert antioncogenic potential in CRC cells by modulating p53 expression. The present study evaluated the association between CSE1L expression and butyrate treatment from two non­transformed colon cell lines (CCD­18Co and FHC) and six CRC cell lines (LS 174T, HCT116 p53+/+, HCT116 p53­/­, Caco­2, SW480 and SW620). Lentiviral knockdown of CSE1L and p53, reverse transcription­quantitative PCR (CSE1L, c­Myc and p53), western blotting [CSE1L, p53, cyclin (CCN) A2, CCNB2 and CCND1], wound healing assay (cell migration), flow cytometry (cell cycle analysis) and immunofluorescence staining (CSE1L and tubulin) were adopted to verify the effects of butyrate on CSE1L­expressing CRC cells. The butyrate­producing gut bacteria Butyricicoccus pullicaecorum was administered to mice with 1,2­dimethylhydrazine­induced colon tumors before the measurement of CSE1L expression. The effects of B. pullicaecorum on CSE1L expression were then assessed by immunohistochemical staining for CSE1L and p53 in tissues from CRC­bearing mice. Non­cancerous colon cells with the R273H p53 mutation or CRC cells haboring p53 mutations were found to exhibit significantly higher CSE1L expression levels. CSE1L knockdown in HCT116 p53­/­ cells resulted in G1­and G2/M­phase cell cycle arrest. Furthermore, in HCT116 p53­/­ cells, CSE1L expression was already high at interphase, increased at prophase, peaked during metaphase before declining at cytokinesis but remained relatively high compared with that in HCT116 expressing wild­type p53. Significantly decreased expression levels of CSE1L were also observed in HCT116 p53­/­ cells that were treated with butyrate for 24 h. In addition, the migration of HCT116 p53­/­ cells was significantly decreased after CSE1L knockdown or butyrate treatment. Tumors with more intense nuclear p53 staining and weaker CSE1L staining were found in mice bearing DMH/DSS­induced CRC that were administered with B. pullicaecorum. Taken together, the results indicated that butyrate can impair CSE1L­induced tumorigenic potential. In conclusion, butyrate­producing microbes, such as B. pullicaecorum, may reverse the genetic distortion caused by p53 mutations in CRC by regulating CSE1L expression levels.

Immunohistochemical analyses of paraffin-embedded sections after primary surgery or trimodality treatment in esophageal carcinoma.

Background: The microscopic tumor extension before, during or after radiochemotherapy (RCHT) and its correlation with the tumor microenvironment (TME) are presently unknown. This information is, however, crucial in the era of image-guided, adaptive high-precision photon or particle therapy. Materials and methods: In this pilot study, we analyzed formalin-fixed paraffin-embedded (FFPE) tumor resection specimen from patients with histologically confirmed squamous cell carcinoma (SCC; n = 10) or adenocarcinoma (A; n = 10) of the esophagus, having undergone neoadjuvant radiochemotherapy followed by resection (NRCHT + R) or resection (R)]. FFPE tissue sections were analyzed by immunohistochemistry regarding tumor hypoxia (HIF-1α), proliferation (Ki67), immune status (PD1), cancer cell stemness (CXCR4), and p53 mutation status. Marker expression in HIF-1α subvolumes was part of a sub-analysis. Statistical analyses were performed using one-sided Mann-Whitney tests and Bland-Altman analysis. Results: In both SCC and AC patients, the overall percentages of positive tumor cells among the five TME markers, namely HIF-1α, Ki67, p53, CXCR4 and PD1 after NRCHT were lower than in the R cohort. However, only PD1 in SCC and Ki67 in AC showed significant association (Ki67: p = 0.03, PD1: p = 0.02). In the sub-analysis of hypoxic subvolumes among the AC patients, the percentage of positive tumor cells within hypoxic regions were statistically significantly lower in the NRCHT than in the R cohort across all the markers except for PD1. Conclusion: In this pilot study, we showed changes in the TME induced by NRCHT in both SCC and AC. These findings will be correlated with microscopic tumor extension measurements in a subsequent cohort of patients.

Efficient intracellular delivery of p53 protein by engineered protein crystals restores tumor suppressing function in vivo.

Direct delivery of proteins into cells holds significant potential for basic research and drug development. However, the poor endosomal escape of conventional delivery strategies remains a challenge, thus limiting the clinical translation of many protein therapeutics. Herein, we report that engineered Cry3Aa protein (Pos3Aa) crystals formed naturally within Bacillus thuringiensis can serve as a vehicle for efficient cytosolic delivery of bioactive proteins. We showed that Pos3Aa-mediated delivery of tumor suppressor p53 protein, a promising therapeutic candidate found to be inactivated in nearly half of human cancers, resulted in the restoration of p53 function in p53-deficient cancer cells, and thereby sensitized them to 5-fluorouracil chemotherapy as demonstrated in in vitro and in vivo models. Our results validate that Pos3Aa crystals can be a robust and effective platform for the cytosolic delivery of effector proteins, and suggest that efficient uptake and endosomal escape could be critical for efficacious p53 protein-based cancer therapy.

Piper crocatum Ruiz & Pav. ameliorates wound healing through p53, E-cadherin and SOD1 pathways on wounded hyperglycemia fibroblasts.

INTRODUCTION: Piper crocatum Ruiz & Pav (P. crocatum) has been reported to accelerate the diabetic wound healing process empirically. Some studies showed the benefits of P. crocatum in treating various diseases but its mechanisms in diabetic wound healing have never been reported. In the present study we investigated the diabetic wound healing activity of the active fraction of P. crocatum on wounded hyperglycemia fibroblasts (wHFs). METHODS: Bioassay-guided fractionation was performed to get the most active fraction. The selected active fraction was applied to wHFs within 72 h incubation. Mimicking a diabetic condition was done using basal glucose media containing an additional 17 mMol/L D-glucose. A wound was simulated via the scratch assay. The collagen deposition was measured using Picro-Sirius Red and wound closure was measured using scratch wound assay. Underlying mechanisms through p53, αSMA, SOD1 and E-cadherin were measured using western blotting. RESULTS: We reported that FIV is the most active fraction of P. crocatum. We confirmed that FIV \(7.81 µg/ml, 15.62 µg/ml, 31.25 µg/ml, 62.5 µg/ml, and 125 µg/ml) induced the collagen deposition and wound closure of wHFs. Furthermore, FIV treatment (7.81 µg/ml, 15.62 µg/ml, 31.25 µg/ml) down-regulated the protein expression level of p53 and up-regulated the protein expression levels of αSMA, E-cadherin, and SOD1. DISCUSSION/CONCLUSIONS: Our findings suggest that ameliorating collagen deposition and wound closure through protein regulation of p53, αSMA, E-cadherin, and SOD1 are some of the mechanisms by which FIV of P. crocatum is involved in diabetic wound healing therapy.