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Nuclear class 3 PI3K co-activates fasting-specific chromatin remodelling.

Transcriptional remodelling during fasting ensures metabolic adaptation and provides health benefits across species. Although several regulators of fasting-induced transcription and chromatin are known, how nutrient levels directly influence RNA polymerase II (RNAPII) and epigenetic writers remains unclear. Here we show that lipid kinase class 3 phosphatidylinositol 3-kinase (PI3K-3), a master regulator of autophagy, also functions on chromatin as a co-activator of epigenetic writers to promote RNAPII transcription. PI3K-3 overlaps with transcriptionally engaged RNAPII phosphorylated at Ser5 and with Setd1a/COMPASS, the complex that deposits the activating H3K4me3 mark. Nuclear PI3K-3 interacts with RNAPII and Setd1a/COMPASS and promotes their chromatin binding. PI3K-3 loss reduces RNAPII-S5p and H3K4me3 at selected genes, whereas PI3K-3 overexpression co-activates p300/CBP and chromatin-targeted PI3K-3 increases H3K4me3. During starvation, PI3K-3 induces autophagy genes and drives fasted liver towards ketogenesis and lipid degradation. These findings link nutrient stress to chromatin-mediated transcriptional activation.

Chromatin Assembly and Disassembly

Oncogenic PIK3CA enhances collective migration of mammary epithelial cells through ERK wave propagation.

Oncogenic mutations of the PIK3CA gene, which encodes the catalytic subunit of the phosphatidylinositol 3-kinase (PI3K) enhance cell migration via ERK (ERK1 and ERK2, also known as MAPK3 and MAPK1, respectively) activation. We analyzed the factors regulating collective cell migration (CCM) of genome-edited MCF10A cell lines carrying hotspot PIK3CA mutations E545K or H1047R. H1047R enhanced CCM and promoted the propagation of waves of ERK activity backwards from the wound edge, whereas E545K impaired both coordinated CCM and ERK activity wave formation. The distance traveled by ERK activity waves correlated with directional persistence of migrating cells. Inhibition of cell contractility stimulated ERK wave propagation and efficient CCM of E545K cells but impaired ERK waves and CCM in control cells. Impaired ERK wave propagation was consistently associated with non-linear cell-cell junctions and the loss of polarized distribution of actomyosin. Taken together, these analyses suggest that polarized actomyosin contractility and pulsatile ERK activation must be constrained in the territory of a phase diagram compatible with mechanotransduction of ERK waves across cell-cell junctions to achieve highly coordinated and efficient collective migration.

Cell Movement

Propionyl-CoA carboxylase subunit B regulates anti-tumor T cells in a pancreatic cancer mouse model.

Most human pancreatic ductal adenocarcinoma (PDAC) are not infiltrated with cytotoxic T cells and are highly resistant to immunotherapy. Over 90% of PDAC have oncogenic KRAS mutations, and phosphoinositide 3-kinases (PI3Ks) are direct effectors of KRAS. Our previous study demonstrated that ablation of Pik3ca in KPC (KrasG12D; Trp53R172H; Pdx1-Cre) pancreatic cancer cells induced host T cells to infiltrate and completely eliminate the tumors in a syngeneic orthotopic implantation mouse model. Now, we show that implantation of Pik3ca-/- KPC (named αKO) cancer cells induces clonal enrichment of cytotoxic T cells infiltrating the pancreatic tumors. To identify potential molecules that can regulate the activity of these anti-tumor T cells, we conducted an in vivo genome-wide gene-deletion screen using αKO cells implanted in the mouse pancreas. The result shows that deletion of propionyl-CoA carboxylase subunit B gene (Pccb) in αKO cells (named p-αKO) leads to immune evasion, tumor progression, and death of host mice. Surprisingly, p-αKO tumors are still infiltrated with clonally enriched CD8+ T cells but they are inactive against tumor cells. However, blockade of PD-L1/PD1 interaction reactivated these clonally enriched T cells infiltrating p-αKO tumors, leading to slower tumor progression and improve survival of host mice. These results indicate that Pccb can modulate the activity of cytotoxic T cells infiltrating some pancreatic cancers and this understanding may lead to improvement in immunotherapy for this difficult-to-treat cancer.

Animals

Whole-Genome Deep Learning Predicts Chemotherapy Response in Colorectal Cancer.

Chemotherapy response in colorectal cancer (CRC) exhibits significant heterogeneity, with current clinical predictors failing to capture complex genomic determinants of resistance. We developed a hybrid deep learning framework integrating convolutional neural networks (CNNs) and bidirectional long short-term memory (BiLSTM) networks to analyze whole-genome somatic mutations, evolutionary conservation, chromatin accessibility, and 3D genome architecture in 2,546 TCGA patients. An attention mechanism identified predictive genomic regions. The model achieved an AUC of 0.92 (95% CI: 0.89-0.94) in cross-validation and 0.88 (95% CI: 0.85-0.91) in independent validation, outperforming clinical models (&#x394;AUC = +0.18, p < 0.001). Key predictors included non-coding variants in TP53, KRAS, and PIK3CA regulatory regions. Triple-positive patients (mutations in all 3 regions) had significantly worse progression-free survival (HR = 4.7, p < 0.001). Our framework enables accurate chemotherapy response prediction and reveals novel non-coding resistance mechanisms, advancing precision oncology in CRC.

Humans

Recurrent FGFR2 and PIK3CA Mutations in Sialoblastoma.

PURPOSE: Sialoblastoma is an extremely rare low-grade malignant salivary gland neoplasm that presents at birth or early infancy and has heterogeneous clinical behavior. Due to its rarity, the molecular landscape remains incompletely characterized. We aimed to expand the current understanding of the genetic alterations in sialoblastoma through comprehensive molecular analysis. METHODS: Five sialoblastoma cases were retrieved from four institutional archives. Clinical and pathologic review was performed, and targeted next-generation sequencing was conducted using clinically validated panels. Copy number analysis was performed on four cases. RESULTS: The cohort included five patients with tumors located in parotid gland (n&#x2009;=&#x2009;2), minor salivary glands (n&#x2009;=&#x2009;2), and submandibular gland (n&#x2009;=&#x2009;1). Four patients were diagnosed before 6 months of age. Histologically, all tumors showed solid organoid nests with primitive basaloid cells, dense fibrous stroma, and mitotic activity ranging from 8 to 25 per 10 high-power fields. Recurrent FGFR2 p.C382R variants were identified in 80% (4/5) of cases. Additional alterations were seen in FGFR2 p.C382R mutated tumors, including PIK3CA hotspot mutations in two cases (p.R88Q, p.R38H) and a truncating FGFR2 variant (p.L776Rfs) in one. The single tumor that lacked FGFR2 mutations harbored a CTNNB1 p.I35T variant and showed more favorable histologic features. Copy number analysis revealed recurrent whole-chromosome gains of chromosomes 8, 10, and 11. CONCLUSION: A distinct subset of sialoblastoma has FGFR2 p.C382R hotspot mutation as the predominant driver mutation. Tumors with this mutation tend to have solid growth pattern, aggressive histologic features, and clinical behavior. The identification of concurrent genomic alterations expands the molecular landscape of this rare tumor. The detection of alternative drivers, such as CTNNB1 hotspot mutations typical of basal cell adenoma, also suggests that a subset of sialoblastoma may represent other salivary gland tumors presenting in infancy.

Humans

The genomic landscape of HER2 negative metastatic breast cancer with loss of estrogen and progesterone receptors.

INTRODUCTION: Loss of estrogen receptor (ER) and/or progesterone receptor (PR) might occur during the metastatic progression of ER positive and HER2 negative (ER+/HER2-) breast cancer (BC), but the underpinning molecular alterations remain elusive. We explored the genomic context of HER2- tumors with ER and/or PR loss to investigate potential drivers and actionable alterations that might help personalize treatment of ER+/HER2- BC. METHODS: We accessed data from metastatic HER2- BC included in the MSK-2018 dataset to compare outcome, tumor characteristics and genomic alterations of BC with loss of ER (ER+/-, n&#xa0;=&#xa0;66) to those maintaining ER positivity (ER+/+, n&#xa0;=&#xa0;364) or ER negativity (ER-/-, n&#xa0;=&#xa0;50). We also compared metastatic ER+/+ BC with loss of PR (PR+/-, n&#xa0;=&#xa0;111) to those maintaining PR positivity (PR+/+, n&#xa0;=&#xa0;192) or PR negativity (PR-/-, n&#xa0;=&#xa0;41). RESULTS: In line with previous reports, ER+/-&#xa0;BC was associated with aggressive clinico-pathological characteristics and poor outcome. ER+/-&#xa0;BC showed significantly higher frequency of TP53 and RB1 mutations and lower frequency of PIK3CA and GATA3 mutations compared to ER+/+. ER+/-&#xa0;or PR+/-&#xa0;status was mutually exclusive with ESR1 mutations and was associated with a significantly higher tumor mutational burden. Moreover, ER+/-&#xa0;BC were enriched in driver alterations in the genes of the Notch and Retinoblastoma pathways and showed a significantly lower frequency of level 1 actionable alterations according to OncoKB. CONCLUSIONS: Loss of ER and/or PR may identify a distinct evolutionary trajectory of ER+/HER2- metastatic progression, largely non-overlapping with ESR1-mutant endocrine resistance. Further studies on matched primary and metastatic samples are warranted.

Humans

Molecular and immune profiling of HER2-low, HER2 ultra-low, and HER2-null male breast cancer.

BACKGROUND: HER2 expression is described along a biological continuum from null to positive and serves as a critical biomarker for therapeutic guidance in breast cancer (BC). While HER2-low and ultra-low categories have emerged as actionable targets for antibody-drug conjugates (ADCs) in female BC, their molecular and immune characteristics remain largely unexplored in male breast cancer. METHODS: We profiled 214 male breast tumors using next-generation sequencing and whole-transcriptome sequencing to assess mutational, transcriptomic, and immune landscapes. Tumor mutational burden (TMB) was defined as high if&#x202f;>&#x202f;10 mutations/Mb. Immune cell fractions were inferred using Quantiseq deconvolution. RESULTS: Among 214 samples, 66 (30.8%) were HER2-null, 53 (24.8%) HER2 ultra-low, 80 (37.4%) HER2-low, and 15 (7.0%) HER2-positive. HER2 ultra-low tumors exhibited a higher prevalence of PIK3CA mutations (39.2% vs 22.6%, p&#x202f;&#x2264;&#x202f;0.05) compared to HER2-null. No significant differences were observed in TMB-high frequency or PD-L1 expression across subgroups. Immune composition differed primarily between HER2-null and HER2-expressing subgroups: HER2-ultra-low tumors showed higher B-cell infiltration, whereas HER2-null tumors were enriched in neutrophils. Transcriptomic analysis revealed upregulation of selected stemness-associated genes (NANOG, KLF4, POU5F1) and CEACAM1 in HER2-null tumors, while HER2-low and HER2-ultra-low tumors were largely similar across most molecular and immune readouts in this cohort. CONCLUSIONS: HER2-null male breast cancer appears to represent the most biologically divergent subgroup within the HER2-negative spectrum, whereas HER2-low and HER2-ultra-low tumors were largely similar in this cohort. These findings support further investigation of HER2-null disease as a distinct biological state and provide hypothesis-generating data for biomarker development in this rare population.

Male

Detection of heterogeneous resistance mechanisms to tyrosine kinase inhibitors from cell-free DNA.

Though there has been substantial progress in the development of anti-human epidermal growth factor receptor 2 (HER2) therapies to treat HER2-positive metastatic breast cancer (MBC) within the past two decades, most patients still experience disease progression and cancer-related death. HER2-directed tyrosine kinase inhibitors can be highly effective therapies for patients with HER2-positive MBC; however, an understanding of resistance mechanisms is needed to better inform treatment approaches. We performed whole-exome sequencing on 111 patients with 73 tumor biopsies and 120 cell-free DNA samples to assess mechanisms of resistance. In 11 of 26 patients with acquired resistance, we identified alterations in previously characterized genes, such as PIK3CA and ERBB2, that could explain treatment resistance. Mutations in growing subclones identified potential mechanisms of resistance in 5 of 26 patients and included alterations in ESR1, FGFR2, and FGFR4. Additional studies are needed to assess the functional role and clinical utility of these alterations in driving resistance.

Humans

Multitargeted comparative evaluation suggests 2-Aoeobenoxmide shows favourable in silico binding compared to Tucatinib against ER&#x3b1;, HER2, AKT1, EGFR, and PIK3CA in breast cancer.

Breast cancer is a leading cause of cancer-related morbidity and mortality globally, with the WHO reporting approximately 2.3 million new cases and 685,000 deaths annually. Drug resistance in breast cancer complicates treatment, with mutations in critical proteins contributing to therapy failure. Key oncogenic proteins involved in breast cancer progression-namely ER&#x3b1; (a ligand-activated nuclear receptor; PDB: 1A52) and the kinase domains of HER2 (PDB ID: 3PP0), AKT1 (PDB ID: 4EJN), EGFR (PDB ID: 4I23) and PIK3CA (PDB ID: 7R9V)-are pivotal in tumour progression and resistance mechanisms. Targeting these proteins using multitargeted therapeutic strategies may overcome resistance by disrupting key signalling pathways involved in cell proliferation, survival, and metastasis. Such combinatorial approaches promise to improve treatment efficacy and patient outcomes in cases of resistant breast cancer. In this study, we performed multitarget docking on prepared and validated protein structures against the ZINC natural compound library using HTVS, SP, and XP, with pose validation using MM-GBSA. We identified 2-Aoeobenoxmide (2-[1-(2-amino-2-oxo-ethoxy)-6-oxo-benzo[c]chromen-3-yl]oxyacetamide, ZINC134008) with docking and MM-GBSA scores ranging from -8.162 to -10.327 kcal/mol and from -47.18 to -57.62 kcal/mol, respectively, and compared the results with the FDA-approved drug Tucatinib, which exhibited lower binding affinity scores. We further evaluated pharmacokinetic properties using QikProp and electronic properties using DFT (Jaguar) and compared the descriptors of 2-Aoeobenoxmide with those of Tucatinib and with accepted reference ranges. We also performed the WaterMap for 5 nanoseconds (ns), computed various energies, interactions and hydration sites, and the comparison suggests that 2-Aoeobenoxmide shows more favourable hydration-site displacement and binding interactions than Tucatinib. Additionally, a 100 ns MD Simulation has resulted in far less deviation, fluctuations, and intermolecular interactions than Tucatinib, suggesting stable protein-ligand interactions, while the binding free energy and total complex energy computed across 0-1000 frames of the MD trajectories indicate that 2-Aoeobenoxmide is a promising in silico candidate. Importantly, because the entire study is computational, the findings should be interpreted as in silico hypotheses, and experimental validation through in vitro and in vivo assays is warranted before any clinical translation is considered.

Humans

High tumor mutational burden and PIK3CA mutations correlate with poor Merkel cell carcinoma-specific survival.

Merkel cell carcinoma (MCC) is a neuroendocrine carcinoma of the skin characterized by poor prognosis. This study aimed to explore the relationship between genetic alterations, tumor mutational burden (TMB), and MCC-specific survival (MCC-SS) in patients who underwent genomic profiling of tumors with OncoPanel. Univariate and multivariable analysis were used to assess the impact of genetic alterations on MCC-SS. Of the 188 identified patients, 164 were included in the analysis. The cohort had a mean age of 72.4 years (SD = 11.03), including 61.6% male. The median TMB was 5.32 (IQR = 3.04-25.53). Kaplan-Meier curves by high versus low TMB were significantly different (log-rank test, P = 0.017). PIK3CA (adjusted P = 0.003), SETBP1 (adjusted P = 0.002), KDR (adjusted P = 0.028), and RET (adjusted P = 0.033) were selected for multivariable analysis. In the multivariable regressions, only PIK3CA (HR = 2.07 [95% CI, 1.10-3.88]; P = 0.024) remained significant. PIK3CA remained significant across prespecified sensitivity analyses. In this study, high TMB and PIK3CA alterations were associated with poor MCC-SS. Identifying a higher-risk subgroup may inform risk stratification and motivate further evaluation of PI3K pathway targeting in future studies.

Humans

Single cell mutational analysis of PIK3CA in circulating tumor cells and metastases in breast cancer reveals heterogeneity, discordance, and mutation persistence in cultured disseminated tumor cells from bone marrow.

BACKGROUND: Therapeutic decisions in cancer are generally guided by molecular biomarkers or, for some newer therapeutics, primary tumor genotype. However, because biomarkers or genotypes may change as new metastases emerge, circulating tumor cells (CTCs) from blood are being investigated for a role in guiding real-time drug selection during disease progression, expecting that CTCs will comprehensively represent the full spectrum of genomic changes in metastases. However, information is limited regarding mutational heterogeneity among CTCs and metastases in breast cancer as discerned by single cell analysis. The presence of disseminated tumor cells (DTCs) in bone marrow also carry prognostic significance in breast cancer, but with variability between CTC and DTC detection. Here we analyze a series of single tumor cells, CTCs, and DTCs for PIK3CA mutations and report CTC and corresponding metastatic genotypes. METHODS: We used the MagSweeper, an immunomagnetic separation device, to capture live single tumor cells from breast cancer patients' primary and metastatic tissues, blood, and bone marrow. Single cells were screened for mutations in exons 9 and 20 of the PIK3CA gene. Captured DTCs grown in cell culture were also sequenced for PIK3CA mutations. RESULTS: Among 242 individual tumor cells isolated from 17 patients and tested for mutations, 48 mutated tumor cells were identified in three patients. Single cell analyses revealed mutational heterogeneity among CTCs and tumor cells in tissues. In a patient followed serially, there was mutational discordance between CTCs, DTCs, and metastases, and among CTCs isolated at different time points. DTCs from this patient propagated in vitro contained a PIK3CA mutation, which was maintained despite morphological changes during 21 days of cell culture. CONCLUSIONS: Single cell analysis of CTCs can demonstrate genotypic heterogeneity, changes over time, and discordance from DTCs and distant metastases. We present a cautionary case showing that CTCs from any single blood draw do not always reflect metastatic genotype, and that CTC and DTC analyses may provide independent clinical information. Isolated DTCs remain viable and can be propagated in culture while maintaining their original mutational status, potentially serving as a future resource for investigating new drug therapies.

Bone Marrow

Age-related genomic characterization and therapeutic targets in Chinese breast cancer: insights from prospective targeted sequencing and clinical data analysis.

BACKGROUND: In China, breast cancer occurs at a much younger age and has a higher recurrence and mortality rate. However, with changes in lifestyle, there has been a trend towards an older age of breast cancer incidence in Chinese women. There is a paucity of large-scale next-generation sequencing cohorts for the analysis of genomic characterization in these populations and the identification of potential therapeutic targets. METHODS: To address this gap, we performed prospective targeted sequencing of tumor and blood samples from Chinese patients and collected detailed clinical information. We then categorized patients into two groups based on age (<&#x2009;40&#xa0;years, n&#x2009;=&#x2009;637;&#x2009;&#x2265;&#x2009;40&#xa0;years, n&#x2009;=&#x2009;3442) and proceeded to provide comprehensive descriptions of somatic and germline mutations in both groups. RESULTS: The somatic mutation analysis revealed that PIK3CA, FOXA1, and TBX3 mutations were more prevalent in elderly patients. By leveraging the aforementioned mutational characteristics, we employed our institution's FUTURE-SUPER clinical trial, an umbrella study targeting metastatic breast cancer, to confirm the potential benefits of PI3K-AKT-mTOR pathway inhibitors among elderly patients with breast cancer. Furthermore, TP53 and ERBB2 were more likely to be co-mutated in young women. Patients with TP53 and ERBB2 co-mutation tend to have a poorer prognosis, but through investigation of the SPARK cohort, patients carrying the TP53 and ERBB2 co-mutation are more likely to benefit from immune checkpoint inhibitor combination with tyrosine kinase inhibitor therapy. In our study, we observed a higher frequency of mutations in the DNA homology-dependent recombination pathway in young patients with breast cancer, which was associated with an elevated Ki67 index. Additionally, we confirmed a significant prevalence of germline breast cancer susceptibility gene 1 (gBRCA1) mutations in young patients, whereas germline checkpoint kinase 2 (gCHEK2) mutations are more common in elderly patients. CONCLUSIONS: Our study, which makes use of the largest Chinese breast cancer sequencing cohort, sought to characterize the age-related genomic profile of breast cancer patients and identify novel therapeutic opportunities for individuals with breast cancer.

Adult

In-depth assessment of BRAF, NRAS, KRAS, EGFR, and PIK3CA mutations on cell-free DNA in the blood of melanoma patients receiving immune checkpoint inhibition.

INTRODUCTION: Circulating tumor DNA (ctDNA) holds promise for guiding immune checkpoint inhibitor (ICI) therapy and stratifying responders from non-responders. While tumor-informed ctDNA detection approaches are sensitive and mutation-inclusive, they require tumor tissue, which limits applicability in real-world settings. Conversely, tumor-agnostic methods often have limited genomic coverage. In this study, we evaluated a tumor-agnostic, broad-panel ctDNA assay in patients with advanced melanoma treated with ICI. METHODS: We conducted a prospective analysis of 241 longitudinal samples from 39 patients with unresectable stage III/IV melanoma using a SYSMEX targeted NGS panel covering 1,114 COSMIC mutations. Plasma samples were collected at baseline and during ICI therapy. The assay's sensitivity reached seven mutant molecules, corresponding to a 0.07% mutation allele frequency (MAF). ctDNA profiles were compared with matched tumor tissue and correlated with clinical features and survival. RESULTS: At baseline, ctDNA was detected in 64.5% of patients. Common mutations included BRAFV600E (43.8%) and NRASG12D (36.4%), followed by KRAS, EGFR, and PIK3CA variants. Overall tissue-plasma concordance was 51.6%, with more extended biopsy-plasma intervals associated with discordance (p&#x2009;=&#x2009;0.0105). Notably, 12.2% of cases exhibited partial concordance, characterized by shared mutations and additional plasma-only alterations, underscoring the complementary value of blood-based profiling. Persistent or re-emerging ctDNA positivity post-therapy correlated with shorter progression-free survival (PFS, p&#x2009;=&#x2009;0.003), while ctDNA-negative patients showed significantly improved outcomes. Patients that remained ctDNA-negative had significantly longer progression-free survival (median not reached) compared to those with persistent ctDNA positivity (median 3&#xa0;months) or those converting to positive (median 7.5&#xa0;months; p&#x2009;=&#x2009;0.0073). Early NRAS and KRAS ctDNA levels strongly predicted poor response (p&#x2009;=&#x2009;0.0069 and p&#x2009;=&#x2009;0.028). The prognostic impact extended beyond canonical drivers, as non-hotspot variants also correlated with the outcome. Notably, even low-level ctDNA persistence (5-10 MM/mL) carried adverse prognostic implications (p&#x2009;=&#x2009;0.0054). Concerning a shorter PFS, ctDNA positivity was also associated with elevated S100 levels (p&#x2009;=&#x2009;0.047). Organ-specific mutation enrichment (e.g., KRASG12D in brain, EGFRG719A in lymph nodes) suggested possible metastatic tropism. CONCLUSION: Broad tumor-agnostic ctDNA analysis effectively identified clinically relevant mutations and predicted outcomes in ICI-treated melanoma patients. This approach enables tissue-independent and real-time ctDNA monitoring and may inform patient selection and therapeutic strategies in future interventional trials.

Humans

Identification of breast cancer-associated PIK3CA H1047R mutation in blood circulation using an asymmetric PCR assay.

PURPOSE: To establish a highly sensitive and specific approach for the detection of circulating PIK3CA H1047R mutation in breast cancer (BC) patients and to investigate the association between the prevalence of PIK3CA H1047R mutation and clinical presentations. METHODS: A proper blocker was designed in an allele-specific manner and optimized for PCR-based identification of the PIK3CA H1047R mutation. The established technique was validated in cell-free DNA samples from 196 recruited BC patients. RESULTS: The allele-specific PCR assay with a properly designed blocker was able to detect the H1047R mutant variant with 0.01%. By applying the newly established assay, 62 cases (31.6% of the total recruited cases) were found to carry a blood-circulating H1047R mutant. Wherein, the detected mutant rates increased with disease stages from 2/18 (11.1%) of stage I to 17/71 (23.9%) of stage II, 20/53 (37.7%) of stage III, and 23/31 (42.6%) of stage IV (p = 0.025), respectively. Higher frequencies of H1047R mutation were associated with late-stage (p = 0.033) or recurrence (p = 0.045) or metastatic patients (p = 0.049) as well as radiation-treated human epidermal growth factor receptor 2 (HER2) positive BC (p = 0.004). PIK3CA mutant carriers were frequently observed in patients under the age of 50 who had liver-metastasized or brain metastases or lymph node-invaded (p < 0.05). CONCLUSION: A novel allele-specific PCR assay with high sensitivity was established successfully for the detection of the PIK3CA H1047R mutation in clinical practice.

Humans

PIK3CA Polymorphisms in Cervical Cancer: Differential Impact of rs6443624 and rs141178472.

BACKGROUND: Cervical cancer remains a major cause of mortality in low- and middle-income settings. We assessed whether two PIK3CA single-nucleotide polymorphisms (SNPs) rs6443624 (A/C) and rs141178472 (C/T) are associated with disease risk, clinicopathological features, and survival. MATERIALS AND METHODS: In a prospective case control study at a tertiary center, 154 participants were enrolled (77 cases, 77 controls). Genomic DNA was isolated from FFPE cervical tumors (QIAamp DNA FFPE Tissue Kit) and genotyped using TaqMan allelic discrimination. Clinicopathological variables (FIGO stage, histology, grade, treatment, tumor-infiltrating lymphocytes [TILs]) were abstracted from records. Genotype distributions were compared by Pearson chi-square. Associations with clinicopathological features used chi-square/Fisher's exact as appropriate; ANOVA compared age across genotypes. Overall survival (OS) was estimated by Kaplan-Meier and compared with the log-rank test; mean OS with SE and 95% CI is reported. RESULTS: Cases were predominantly locally advanced at presentation and squamous histology; most were moderately differentiated. rs6443624 differed significantly between cases and controls (&#x3c7;&#xb2;=21.1, p<0.001), with CC over-represented in cases and CA less frequent. rs141178472 showed no significant case control difference (&#x3c7;&#xb2;=2.9, p=0.086). For OS, rs6443624 showed a significant genotype effect (log-rank &#x3c7;&#xb2;=23.45, p=0.001): AA had the poorest survival, CA the longest, CC intermediate. rs141178472 was not associated with OS (&#x3c7;&#xb2;=1.06, p=0.588). Genotype clinicopathological correlations for stage group, grade, TILs, and treatment were non-significant or inconsistent, with some comparisons limited by small sample sizes. CONCLUSION: The PIK3CA rs6443624 variant appears to influence both susceptibility and prognosis in cervical cancer, highlighting its potential as a biomarker for molecular risk stratification. Validation in larger, multi-center cohorts incorporating HPV/p16 assessment and extended follow-up is warranted to confirm its clinical relevance.

Humans

Lipid transfer proteins and PI4KII&#x3b1; generate a phosphoinositide-linked proteome.

Phosphoinositide (PIPn) lipid second messengers in membranes regulate numerous cellular processes. In the cytosol, the phosphatidylinositol (PI) 3-kinase (PI3K)/Akt pathway is scaffolded on IQGAP1 to facilitate the activation of Akt by the synthesis of PI3,4,5P3. In the nucleus, PIPn signaling occurs in compartments separate from membranes by stably linking PIPns to nuclear proteins. While several of these proteins have been identified, understanding the extent and impact of protein-linked PIPn signaling warrants further investigation. The tumor suppressor p53, was shown in the companion paper to be regulated by PI transfer proteins (PITPs) and a PI 4-kinase (PI4KII&#x3b1;), which are required to form p53-PIPn complexes that assemble a nuclear PI3K/Akt pathway. Here we report that class I PITPs (PITP&#x3b1;/&#x3b2;) and PI4KII&#x3b1; initiate PIPn linkages to many different proteins. PITP&#x3b1;/&#x3b2; and PI4KII&#x3b1; accumulate in the nucleoplasm in response to stress and are necessary to synthesize nuclear PIPns linked to proteins. These PITP&#x3b1;/&#x3b2;-dependent protein-PIPn complexes are detected by metabolically labeling cells with the PIPn precursor [3H]-myo-inositol and resist denaturation and SDS-PAGE, indicating that these protein-PIPn complexes represent a putative posttranslational modification. Proteomic and gene set enrichment analysis of proteins that are linked to PI4,5P2 reveals an emerging PIPn-linked proteome (PIPylome) regulated by PITP&#x3b1;/&#x3b2; and enriched in proteins that play key functional roles in metabolism, cell motility/division, and the DNA damage response. The PIPn-linked proteome represents a third messenger signaling paradigm distinct from the canonical membrane-localized pathway whereby linked PIPn messengers regulate protein function.

Phosphatidylinositols