Biology subjects

Majidi, M.

Publications and source records attributed to Majidi, M..

6 recordsLinked to original sources

bioRxiv2025

Effects of mixing technique and ethanol removal on lipidnanoparticle physicochemical properties

Optimizing the production of lipid nanoparticle (LNP) therapeutics is necessary for drug delivery efficiency, stability, and scalability. A small but growing body of literature has begun to recognize that LNP properties (e.g., size, shape, and internal structure) depend on the flow conditions during mixing for antisolvent precipitation, in which LNPs are formulated. Here, we use different mixers, varying flow patterns (e.g., laminar or turbulent mixing) and flow rate ratios (FRR), i.e., 3:1 and 1:1, to prepare a standard LNP formulation. We then characterize the resulting formulations using small angle x-ray scattering (SAXS) to provide insights into particle shape/morphology, internal organization (L and HII phases) of yeast RNA (yRNA), and structural differences/similarities that arise from the different mixing methods. The effect of ethanol removal on the LNPs structure, formulated from each mixing technique, is also discussed. We observed the 3:1 FRR mixers outperform the 1:1 configurations in certain desired LNP physiochemical properties. The differences observed in the LNPs produced across the two configurations are discussed. Furthermore, we use computational fluid dynamics to explain the turbulent mixing schemes among the 3:1 and 1:1 mixers.

biophysics↗

bioRxiv2025

Acquired resistance to sotorasib in mutant NSCLC is vulnerable to PI3K-mTOR pathway inhibition mediated by 4E-BP1 regulator of cap-dependent translation

Sotorasib and adagrasib have shown significant efficacy in KRASG12C mutant NSCLC; however, acquired resistance (AR) occurs within 6-12 months. While some resistance arises from new mutations, over half of the resistant cases lack identifiable genomic alterations. We hypothesize that resistance is driven by signaling network rewiring, creating new therapeutic vulnerabilities. To investigate AR mechanisms, multiple AR models, including cell lines, PDXs, CDXs, and PDXOs, were developed. H23AR and H358AR cells displayed >600-fold and 200-fold; and PDXO303AR and PDXO314AR organoids exhibited >300-fold and >100-fold resistance to sotorasib, respectively; however, no additional mutations in KRAS or other potential genetic alterations were identified. The AR cells and PDXOs also showed comparable resistance to adagrasib. Distinct protein signatures associated with KRAS reactivation, mTORC1 signaling upregulation, and PI3K/AKT/mTOR pathway activation were identified in TC303AR & TC314AR PDXs. PI3K protein levels were significantly elevated in AR PDXs, H23AR, and H358AR cells. Pharmacological inhibition of PI3K with copanlisib or genetic knockout via CRISPR-Cas9 restored sotorasib sensitivity, suppressed colony formation, and inhibited downstream effectors, including p-AKT, p-mTOR, p-S6, p70S6K, p-GSK3{beta}, and p-PRAS40 in AR cells. Copanlisib also sensitized both acquired and primary resistant PDXOs and synergized with sotorasib in restoring drug sensitivity. p4E-BP1 was significantly upregulated in H23AR and H358AR cells, which is suppressed by copanlisib. The level of p4E-BP1 expression was correlated with Sotorasib sensitivity in PI3K knockout clones, where the most sensitive clone displayed reduced or no p4E-BP1 expression. CRISPR-Cas9-mediated knockout of 4E-BP1, either alone or in combination with PI3K knockout, dramatically restored sotorasib sensitivity to levels comparable to parental cells. Suppression of 4E-BP1 hyperphosphorylation required dual inhibition of mTORC1 and mTORC2, and treatment with AZD8055 or sapanisertib (mTORC1/2 dual inhibitors) significantly dephosphorylated 4E-BP1 and restored sotorasib sensitivity in resistant cells and PDXOs. In PDX, CDX, and xenograft models in vivo, the combination of sotorasib with either copanlisib or sapanisertib resulted in robust, synergistic, and durable tumor regression at well-tolerated doses. These findings showed the critical role of PI3K/mTOR signaling as a bypass mechanism of resistance to KRASG12C inhibitors. We conclude that mTORC1/2 mediated inhibition of p4E-BP1 and combination strategies targeting this pathway effectively overcome acquired resistance to KRASG12C inhibitors in NSCLC.

cancer biology↗

bioRxiv2024

NPRL2 gene therapy induces effective antitumor immunity in KRAS/STK11 mutant anti-PD1 resistant metastatic non-small cell lung cancer (NSCLC) in a humanized mouse model

NPRL2/TUSC4 is a tumor suppressor gene whose expression is reduced in many cancers including NSCLC. Restoration of NPRL2 expression in cancer cells induces DNA damage which leads to cell cycle arrest and apoptosis. We investigated the antitumor immune responses to NPRL2 gene therapy in aPD1R/ KRAS/STK11mt NSCLC in a humanized mouse model. Humanized mice were generated by transplanting fresh human cord blood derived CD34 stem cells into sub-lethally irradiated NSG mice. Lung metastases were developed from KRAS/STK11mt/aPD1R A549 cells in humanized mice and treated with NPRL2 gene-loaded cationic lipid nanoparticles (DOTAP-NPRL2) with or without pembrolizumab (aPD1). NPRL2 treatment reduced lung metastases significantly, whereas pembrolizumab was ineffective. The antitumor effect was greater in humanized than non-humanized mice suggesting that an immune response contributed to antitumor activity. NPRL2 combined with pembrolizumab was not synergistic in the KRAS/STK11mt/aPD1R tumors but was synergistic in the KRASwt/aPD1S H1299 tumors. Consistent with the A549 humanized mouse model, NPRL2 showed a significantly strong antitumor effect on KRASmt/aPD1R LLC2 syngeneic tumors, whereas aPD1 was ineffective. The antitumor effect of NPRL2 was correlated with increased infiltration of human cytotoxic immune cells and Ag-presenting HLA-DR+ DC, CD11c DC, and downregulation of myeloid and regulatory T cells in the TME. The antitumor effect of NPRL2 was significantly abolished upon in-vivo depletion of CD8 T, macrophages, and CD4 T cells. However, the antitumor effect remained unaffected upon in-vivo depletion of NK cells. A distinct pattern of gene expression profile was found in lung met after NPRL2 treatment in humanized mice. The expression of genes associated with T cell functions, including IFN{gamma}, CD8b, CD7, TNFSF18, ITGA1, GATA3, and TBX21 was significantly increased, whereas the expression of genes associated with negative regulation of T cell functions, including FOXP3, TGFB1, TGFB2, and IL-10RA were strongly inhibited upon NPRL2 treatment. NPRL2 downregulated the expression of T cell co-inhibitory molecules, including CTLA4, ICOS, LAG3, PDCD1, CD274, IDO1, PDCD1LG2, CD47, and KLRB1. Tumors established from NPRL2 stably expressing cells in humanized mice exhibited significantly slower growth compared to controls. TME analysis showed an increased presence of human CD45+, CD3+ T, CD8+ T cells, and HLA-DR+ dendritic cells and a decreased percentage of Treg, CD3+PD1+T cells, MDSC, and CD163+ TAM in NPRL2-expressing tumors. In-vitro, NPRL2 stably expressing cells showed a substantial increase in colony formation inhibition and heightened sensitivity to carboplatin in colony formation, apoptosis, and PARP cleavage assays. Stable expression of NPRL2 resulted in the downregulation of MAPK and AKT-mTOR growth signaling through inhibition of pAKT, pmTOR, pPRAS40, p4E-BP1, and pS6 expression. Taken together, these data suggest that NPRL2 gene therapy induces antitumor activity on KRAS/STK11mt/aPD1R tumors through DC-mediated antigen presentation and cytotoxic immune cell activation.

cancer biology↗

bioRxiv2021

3-Phosphoinositide-dependent kinase 1 drives acquired resistance to osimertinib

Osimertinib sensitive and resistant NSCLC NCI-H1975 clones were used to model osimertinib acquired resistance in humanized mice and delineate potential resistance mechanisms. No new EGFR mutations or loss of the EGFR T790M mutation were found in resistant clones. Resistant tumors in humanized mice were initially partially responsive to osimertinib, then aggressive tumor regrowth occurred accompanied by an immunosuppressive tumor microenvironment. 3-phosphoinositide-dependent kinase 1 (PDK1) was identified as a potential driver of osimertinib acquired resistance, and its selective inhibition by BX795 and CRISPR gene knock out, sensitized resistant clones and a patient derived xenograft (PDX) with acquired resistance to osimertinib. PDK1 knock-out dysregulated PI3K/Akt/mTOR signaling, promoted cell cycle arrest at the G1 phase, and inhibited nuclear translocation of yes-associated protein (YAP). Higher expression of PDK1 was found in patients with progressive disease following osimertinib treatment. PDK1 is a central upstream regulator of two critical drug resistance pathways: PI3K/AKT/mTOR and YAP.

cancer biology↗

bioRxiv2021

A focal adhesion kinase-YAP signaling axis drives drug tolerant persister cells and residual disease in lung cancer

Targeted therapy is effective in many tumor types including lung cancer, the leading cause of cancer mortality. Paradigm defining examples are targeted therapies directed against non-small cell lung cancer (NSCLC) subtypes with oncogenic alterations in EGFR, ALK and KRAS. The success of targeted therapy is limited by drug-tolerant tumor cells which withstand and adapt to treatment and comprise the residual disease state that is typical during treatment with clinical targeted therapies. Here, we integrate studies in patient-derived and immunocompetent lung cancer models and clinical specimens obtained from patients on targeted therapy to uncover a focal adhesion kinase (FAK)-YAP signaling axis that promotes residual disease during oncogenic EGFR-, ALK-, and KRAS-targeted therapies. FAK-YAP signaling inhibition combined with the primary targeted therapy suppressed residual drug-tolerant cells and enhanced tumor responses. This study unveils a FAK-YAP signaling module that promotes residual disease in lung cancer and mechanism-based therapeutic strategies to improve tumor response.

cancer biology↗

bioRxiv2017

Quality Assessment of High-throughput DNA Sequencing Data via Range analysis

In the recent literature there appeared a number of studies for the quality assessment of sequencing data. These efforts, to a great extent, focused on reporting the statistical parameters regarding to the distribution of the quality scores and/or the base-calls in a FASTQ file. We investigate another dimension for the quality assessment motivated with the fact that reads including long intervals having fewer errors improve the performances of the post-processing tools in the down-stream analysis. Thus, the quality assessment procedures proposed in this study aim to analyze the segments on the reads that are above a certain quality. We define an interval of a read to be of desired quality when there are at most k quality scores less than or equal to a threshold value v, for some v and k provided by the user. We present the algorithm to detect those ranges and introduce new metrics computed from their lengths. These metrics include the mean values for the longest, shortest, average, cubic average, and average variation coefficient of the fragment lengths that are appropriate according to the v and k input parameters. We provide a new software tool QASDRA for quality assessment of sequencing data via range analysis. QASDRA, implemented in Python, and publicly available at https://github.com/ali-cp/QASDRA.git, creates the quality assessment report of an input FASTQ file according to the user specified k and v parameters. It also has the capabilities to filter out the reads according to the metrics introduced.

bioinformatics↗