Biology subjects

Jiang, Y.-P.

Publications and source records attributed to Jiang, Y.-P..

8 recordsLinked to original sources

bioRxiv2026

Loss of PIK3CA allows in vitro growth but not in vivo progression of KRAS mutant lung adenocarcinoma in a syngeneic orthotopic implantation model

Constitutively active KRAS mutations are highly prevalent in lung cancers, but the direct role of its downstream phosphatidylinositol 3-kinase (PI3K) pathway in tumor progression remains unclear. A previous study established the requirement for PIK3CA, the alpha catalytic isoform, in lung tumor development in mouse models with an intact Trp53 tumor suppressor. In this study, we further investigated the requirement for PIK3CA for tumor growth both in vitro and in vivo. We first generated a "KPA" cell line by genetically deleting Pik3ca from a murine lung adenocarcinoma "KP" cell line harboring oncogenic KrasG12D and lacking Trp53. We found that Pik3ca is not required for cell survival and growth in vitro, even under anchorage-independent conditions but reduced the growth rate by 20%. We next orthotopically implanted KP and KPA cells into syngeneic mice and found that PIK3CA is absolutely required for tumor progression, even in the absence of Trp53. Implantation of KP cells, or a "KPS" cell line lacking the Stk11 gene, led to rapid tumor growth and death of all host animals. In contrast, mice implanted with KPA cells all survived with no detectable lung tumors. The gene expression profiles from cultured cell lines suggest KPA cells may be vulnerable to oxidative stress. Indeed, we found KPA cells were more sensitive to hydrogen peroxide and diethyl maleate-induced oxidative stress as compared to KP and KPS cells. Together, these results demonstrate that PIK3CA is not required for lung cancer cell growth induced by mutant KRAS in vitro but is critically needed for in vivo progression and growth.

cancer biology↗

bioRxiv2025

Engineered Promoter System Enables High-efficiency Transgenic CRISPR Editing in Malaria Transmitting Mosquito Anopheles sinensis

The CRISPR/Cas9 system deployed through crosses of transgenic lines expressing Cas9 and gRNA facilitates efficient mutagenesis. However, its application in non-model insects remains limited, primarily due to a lack of well-characterized promoters capable of driving robust and stable expression of Cas9 and gRNA. In the malaria mosquito Anopheles sinensis, we evaluated several ovary-biased promoters--Asvasa2, Aszpg, and Asnanos--for driving Cas9 expression. Notably, the Asvasa2 promoter mediated mutagenesis in nearly 60% of G0 individuals following microinjection of gRNAAswhite. Among four RNA polymerase III promoters derived from AsU6 genes, AsU6-1 yielded the highest gRNA transcriptional output, enabling 62% editing efficiency in G0 offspring. In addition, hybrid crosses between established transgenic lines demonstrated that the Asvasa2-Cas9 and AsU6-1-gRNA combination enabled complete germline editing penetrance, where all F2 progeny inherited the intended mutations. This work provides a essential genetic toolkit for synthetic biology applications in Anopheles mosquitoes and a scalable framework for engineering other non-model insects.

genetics↗

bioRxiv2025

A Critical Role for Neutral Sphingomyelinase-2 in Doxorubicin-induced Cardiotoxicity

Cardiotoxicity is a major side effect of Doxorubicin (Dox) that has hampered its clinical utility, and strategies to mitigate this cardiotoxicity are limited. Sphingolipids (SL) are central to the chemotherapy response in cancer but their role in normal tissue is less clear. Here, we identified the SL enzyme neutral sphingomyelinase-2 (nSMase2) as a critical mediator of chronic Dox-induced cardiotoxicity, establishing nSMase2 as a key downstream effector of Dox in cardiomyocytes (CM) and showing that in vivo loss of nSMase2 activity is protecting against chronic Dox-induced cardiac damage and dysfunction. Biologically, these studies link nSMase2 with Dox-induced CM senescence both in vitro and in vivo and identify the dual specificity phosphatase DUSP4 as a novel effector of nSMase2 in the Dox response. In addition to cementing a role for SL metabolism in Dox effects in normal tissue, this study advances nSMase2 as a target of interest for cardioprotection.

cell biology↗

bioRxiv2024

Down-regulation of AKT proteins slows the growth of mutant-KRAS pancreatic tumors

Serine/threonine kinase AKT isoforms play a well-established role in cell metabolism and growth. Most pancreatic adenocarcinoma (PDAC) harbors activation mutations of KRAS, which activates the PI3K/AKT signaling pathway. However, AKT inhibitors are not effective in the treatment of pancreatic cancer. To better understand the role of AKT signaling in mutant-KRAS pancreatic tumors, this study utilizes proteolysis-targeting chimeras (PROTACs) and CRISPR-Cas9-genome editing to investigate AKT proteins. PROTAC down-regulation of AKT proteins markedly slowed the growth of three pancreatic tumor cell lines harboring mutant KRAS. In contrast, inhibition of AKT kinase activity alone had very little effect on the growth of these cell lines. Concurrent genetic deletion of all AKT isoforms (AKT1, AKT2, and AKT3) in the KPC (KrasG12D; Trp53R172H; Pdx1-Cre) pancreatic cancer cell line also dramatically slowed its growth in vitro and when orthotopically implanted in syngeneic mice. Surprisingly, insulin-like growth factor-1 (IGF-1), but not epidermal growth factor (EGF), restored KPC cell growth in serum-deprived conditions and the IGF-1 growth stimulation effect was AKT dependent. RNA-seq analysis of AKT1/2/3-deficient KPC cells suggested that reduced cholesterol synthesis may be responsible for the decreased response to IGF-1 stimulation. These results indicate that the presence of all three AKT isoforms supports pancreatic tumor cell growth and pharmacological degradation of AKT proteins may be more effective than AKT catalytic inhibitors for treating pancreatic cancer.

cancer biology↗

bioRxiv2023

Propionyl-CoA carboxylase subunit B modulates PIK3CA-regulated immune-surveillance 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 KO) cancer cells induces clonal expansion 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 KO cells implanted in the mouse pancreas. The result shows that deletion of propionyl-CoA carboxylase subunit B gene (Pccb) in KO cells (named p-KO) leads to immune evasion, tumor progression and death of host mice. Surprisingly, p-KO tumors are still infiltrated with clonally expanded CD8+ T cells but they are inactive against tumor cells. However, blockade of PD-L1/PD1 interaction reactivated these clonally expanded T cells infiltrating p-KO 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.

cancer biology↗

bioRxiv2020

Human ACE2 receptor polymorphisms predict SARS-CoV-2 susceptibility

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of coronavirus disease (COVID-19) that has resulted in a global pandemic. It is a highly contagious positive strand RNA virus and its clinical presentation includes severe to critical respiratory disease that appears to be fatal in [~]3-5% of the cases. The viral spike (S) coat protein engages the human angiotensin-converting enzyme2 (ACE2) cell surface protein to invade the host cell. The SARS-CoV-2 S-protein has acquired mutations that increase its affinity to human ACE2 by [~]10-15-fold compared to SARS-CoV S-protein, making it highly infectious. In this study, we assessed if ACE2 polymorphisms might alter host susceptibility to SARS-CoV-2 by affecting the ACE2 S-protein interaction. Our comprehensive analysis of several large genomic datasets that included over 290,000 samples representing >400 population groups identified multiple ACE2 protein-altering variants, some of which mapped to the S-protein-interacting ACE2 surface. Using recently reported structural data and a recent S-protein-interacting synthetic mutant map of ACE2, we have identified natural ACE2 variants that are predicted to alter the virus-host interaction and thereby potentially alter host susceptibility. In particular, human ACE2 variants S19P, I21V, E23K, K26R, T27A, N64K, T92I, Q102P and H378R are predicted to increase susceptibility. The T92I variant, part of a consensus NxS/T N-glycosylation motif, confirmed the role of N90 glycosylation in immunity from non-human CoVs. Other ACE2 variants K31R, N33I, H34R, E35K, E37K, D38V, Y50F, N51S, M62V, K68E, F72V, Y83H, G326E, G352V, D355N, Q388L and D509Y are putative protective variants predicted to show decreased binding to SARS-CoV-2 S-protein. Overall, ACE2 variants are rare, consistent with the lack of selection pressure given the recent history of SARS-CoV epidemics, however, are likely to play an important role in altering susceptibility to CoVs.

genetics↗

bioRxiv2019

Endothelial JAK2V617F mutation leads to thrombosis, vasculopathy, and cardiomyopathy in a murine model of myeloproliferative neoplasm

RationalThe myeloproliferative neoplasms (MPNs) are clonal hematological malignancies characterized by hematopoietic stem cell expansion and overproduction of mature blood cells. Cardiovascular complications are the leading cause of morbidity and mortality in patients with MPNs. The acquired kinase mutation JAK2V617F plays a central role in these disorders. Mechanisms responsible for cardiovascular dysfunction in MPNs are not fully understood, limiting the effectiveness of current treatment. ObjectiveVascular endothelial cells (ECs) play critical roles in the regulation of hemostasis and thrombosis. ECs carrying the JAK2V617F mutation can be detected in patients with MPNs. The goal of this study was to test the hypothesis that the JAK2V617F mutation alters endothelial function to promote cardiovascular complications in patients with MPNs. Methods and ResultsWe employed murine models of MPN in which the JAK2V617F mutation is expressed in specific cell lineages. When JAK2V617F is expressed in both blood cells and vascular ECs, the mice developed MPN and spontaneous, age-related dilated cardiomyopathy with an increased risk of sudden death as well as a prothrombotic and vasculopathy phenotype on histology evaluation. We showed that JAK2V617F-mutant ECs are required for this cardiovascular disease phenotype and the mutation can alter endothelial cell function. Finally, in a more therapeutically oriented approach, we demonstrated that transplantation with wild-type donor marrow cells can improve cardiac function by reversing the left ventricle remodeling process in this JAK2V617F-positive MPN murine model. ConclusionsThese findings suggest that the JAK2V617F mutation alters vascular endothelial function to promote cardiovascular complications in MPNs. Therefore, targeting the MPN vasculature represents a promising new therapeutic strategy for patients with MPNs.

molecular biology↗

bioRxiv2019

PIK3CA in KrasG12D/Trp53R172H Tumor Cells Promotes Immune Evasion by Limiting Infiltration of T Cells in a Model of Pancreatic Cancer

The presence of tumor-infiltrating T cells is associated with favorable patient outcomes, yet most pancreatic cancers are immunologically silent and resistant to currently available immunotherapies. Here we show using a syngeneic orthotopic implantation model of pancreatic cancer that Pik3ca regulates tumor immunogenicity. Genetic silencing of Pik3ca in KrasG12D/Trp53R172H-driven pancreatic tumors leads to infiltration of T cells, complete tumor regression, and 100% survival of immunocompetent host mice. By contrast, Pik3ca-null tumors implanted in T cell-deficient mice progress and kill all of the animals. Adoptive transfer of tumor antigen-experienced T cells eliminates Pik3ca-null tumors in immunodeficient mice. Loss of PIK3CA or inhibition of its effector, AKT, increases the expression of MHC Class I and CD80 on tumor cells. These changes contribute to the increased susceptibility of Pik3ca-null tumors to T cell surveillance. These results indicate that tumor cell PIK3CA-AKT signaling limits T cell recognition and clearance of pancreatic cancer cells. Strategies that target this pathway may yield an effective immunotherapy for this cancer.\n\nSIGNIFICANCEPIK3CA-AKT signaling in pancreatic cancer cells limits T cell infiltration and clearance of tumors by suppressing the surface expression of MHC Class I and CD80. Targeting the PIK3CA-AKT pathway in tumor cells provides a new avenue for discovery of novel pancreatic cancer immunotherapies.

cancer biology↗