Biology subjects

Azhdarinia, A.

Publications and source records attributed to Azhdarinia, A..

6 recordsLinked to original sources

bioRxiv2025

Fibulin-4 is highly expressed in metastatic breast cancer and can serve as a target of peptide-based imaging probes and experimental therapeutics

We have previously reported a cyclic peptide CRAGVGRGC (termed BLMP6) that homes to disseminating tumor cells in mouse cancer models and could be used for metastasis detection and intervention. Here, based on BLMP6 similarity to latent transforming growth factor beta binding protein 4 (LTBP4), we discovered fibulin-4 as a BLMP6 target. We show that BLMP6 mimics the LTBP4 domain binding to fibulin-4 and selectively binds to fibulin-4 in vitro. Fibulin-4 knockout in mouse 4T1 cancer cells abrogated BLMP6 homing to lung metastases. Fibulin-4 expression was found to be increased in invasive and metastatic human breast cancer. AZDye555 fluorophore-labeled BLMP6 was developed as a reagent selectively binding to invasive and metastatic human breast cancer cells in tissue sections and homing to MDA-MB-231 metastases in mice. We show that radiolabeling BLMP6 with 68Ga can be used for the detection of MDA-MB-231 metastases. We designed a peptide-drug conjugate consisting of monomethyl auristatin E (MMAE) and BLMP6 that preferentially kills aggressive cancer cells. Cytotoxicity of MMAE-BLMP6 against MDA-MB-231 tumors was confirmed in vivo. In an immunocompetent mouse model of B16F10 experimental lung metastases, treatment with MMAE-BLMP6 suppressed metastasis growth and improved survival. There was also a trend for metastasis suppression and survival improvement in the MDA-MB-231 experimental metastasis model. Our results suggest that fibulin-4 and BLMP6 may be further developed for the detection and targeting of metastatic human cancers. Statement of significanceThis study identifies fibulin-4 as a protein highly expressed in breast cancer metastasis. It evaluates the application of peptide conjugates targeting fibulin-4 in mouse models as non-invasive probes for metastasis detection and cytotoxic drug delivery.

cancer biology↗

bioRxiv2025

Somatostatin Receptor 2 Overexpression in Hepatocellular Carcinoma: Implications for Cancer Biology and Theranostic Applications

(1) BackgroundSomatostatin receptor 2 (SSTR2) is overexpressed in various tumors, including hepatocellular carcinoma (HCC), yet its role in tumorigenesis remains unclear. This study examines the roles of SSTR2 in the molecular pathology of HCC and explores its potential as a target for SSTR2-directed radiopharmaceuticals in this malignancy. (2) MethodsSSTR2 expression was analyzed across 22 malignancies using TNMplot and specifically in HCC through The Human Protein Atlas. Transcriptomic data, protein expression, and copy number alterations in HCC patients with varying SSTR2 levels were compared using The Cancer Genome Atlas (TCGA). Gene Ontology (GO) enrichment analysis was performed using SRplot, while survival analysis was conducted with GEO datasets. (3) ResultsMost HCC patients exhibit moderate levels of SSTR2 expression. Elevated SSTR2 expression is associated with worse overall and disease-specific survival, as well as the activation of pathways involved in tumor growth and metastasis. Furthermore, SSTR2 expression is linked to key oncogenes and receptor tyrosine kinases. (4) ConclusionsSSTR2 in HCC signifies an oncogenic network and represents a promising therapeutic target to inhibit tumor invasion and serve as a theranostic biomarker. HCC patients with elevated SSTR2 expression could benefit from SSTR2-targeted theranostics, enabling enhanced tumor detection and more effective therapy.

cancer biology↗

bioRxiv2024

SSTR2-targeted theranostics in hepatocellular carcinoma

(1) BackgroundWhile the clinical use of radiolabeled somatostatin analogs is established in neuroendocrine tumors, there is significant interest in expanding their use for other somatostatin receptor 2 (SSTR2)-expressing cancers. This study investigates the utility of SSTR2-targeted theranostics in hepatocellular carcinoma (HCC); (2) MethodsWe measured SSTR2 expression in HCC cell lines and clinical samples using qRT-PCR, Western blot, and a public dataset. We evaluated [67Gallium]Ga-DOTATATE uptake, tested [177Lutetium]Lu-DOTATATE cytotoxicity, and assessed [68Gallium]Ga-DOTATATE tumor targeting in HCC animal models and a patient via PET/CT; (3) ResultsSSTR2 expression was confirmed in HCC cell lines and clinical samples. Radioligand uptake studies validated SSTR2-mediated [67Gallium]Ga-DOTATATE uptake, and [177Lutetium]Lu-DOTATATE treatment reduced cell proliferation. [68Gallium]Ga-DOTATATE PET/CT scans detected tumors in animal models and spinal metastases in a patient with HCC; (4) ConclusionThese findings suggest for the first time that SSTR2-based theranostics could have strong implications for detection and treatment of HCC. Simple SummaryThis study investigates the use of SSTR2-targeted theranostics, combining diagnostic and therapeutic approaches, in hepatocellular carcinoma (HCC). We confirmed significant SSTR2 expression in HCC cells and patient samples, showing that radiolabeled compounds such as [67Ga]Ga-DOTATATE and [177Lu]Lu-DOTATATE, commonly used in neuroendocrine tumors, could also target HCC. In preclinical models and a patient case, PET/CT imaging and treatments demonstrated effective tumor detection and shrinkage. These findings suggest that SSTR2-targeted theranostics could offer a novel, targeted method for diagnosing and treating HCC, potentially improving outcomes for patients with this challenging cancer.

cancer biology↗

bioRxiv2024

Limitations of the radiotheranostic concept in neuroendocrine tumors due to lineage-dependent somatostatin receptor expression on hematopoietic stem and progenitor cells

Radiopharmaceutical therapy (RPT) has become an effective treatment option for neuroendocrine tumors (NETs) and castration-resistant prostate cancer and is in clinical development for a growing number of indications. One of the major advantages of theranostic RPT is that the distribution of radiopharmaceuticals in the human body can be imaged, and radiation doses to the patients organs can be calculated. However, accurate dosimetry may be fundamentally limited by microscopic heterogeneity of radiopharmaceutical distribution. We developed fluorescent analogs of somatostatin-receptor-subtype 2 (SSTR2) targeting Lutetium-177 labelled radiopharmaceuticals that are clinically used in patients with neuroendocrine tumors (NETs) and studied their uptake by hematopoietic stem and progenitor cells (HSPC). Hematopoietic stem cells (HSCs) and multipotent progenitor cells (MPPs) showed high and specific SSTR2-ligand uptake, which was at similar levels as neuroendocrine tumor cells. Furthermore, they displayed a several-fold higher uptake of SSTR2-antagonists than of SSTR2-agonists. HSPC treatment with a 177Lu-labelled antagonist and agonist showed a stronger reduction of HSC proliferation by the antagonist. Due to the scarcity of HSCs and MPPs, their contribution to total bone marrow uptake of SSTR2-ligands is not detectable in imaging-based dosimetry studies. This likely explains why SSTR2-antagonists caused pancytopenia in clinical trials despite safe dosimetry estimates. In conclusion, target expression heterogeneity can lead to underestimation of radiopharmaceutical toxicity and should be considered when designing clinical trials for new radiopharmaceuticals. The implications of our findings go beyond somatostatin receptor-targeted radiopharmaceuticals and suggest more generally that first-in-human studies should not only be guided by radiation dosimetry from imaging studies but should also include careful escalation of the administered therapeutic activity. The MMC technology is modular and can be applied to other peptide or protein-based radiopharmaceuticals to study cellular distribution and potential bone marrow uptake prior to clinical testing.

cancer biology↗

bioRxiv2024

Antibody-drug conjugates targeting EGFR ligand Epiregulin inhibit colorectal tumor growth irrespective of RAS mutational status

As colorectal cancer (CRC) remains a leading cause of cancer-related death, identifying therapeutic targets and approaches is essential to improve patient outcomes. The EGFR ligand epiregulin (EREG) is highly expressed in RAS wildtype and mutant CRC with minimal expression in normal tissues, making it an attractive target for antibody-drug conjugate (ADC) development. In this study, we produced and purified an EREG monoclonal antibody (mAb), H231, that had high specificity and affinity for human and mouse EREG. H231 also internalized to lysosomes, which is important for ADC payload release. ImmunoPET and ex vivo biodistribution studies showed significant tumor uptake of 89Zr-labeled H231 with minimal uptake in normal tissues. H231 was conjugated to either cleavable dipeptide or tripeptide chemical linkers attached to the DNA-alkylating payload duocarmycin DM, and cytotoxicity of EREG ADCs was assessed in a panel of CRC cell lines. EREG ADCs incorporating tripeptide linkers demonstrated the highest potency in EREG-expressing CRC cells irrespective of RAS mutations. Preclinical safety and efficacy studies showed EREG ADCs were well-tolerated, neutralized EGFR pathway activity, caused significant tumor growth inhibition or regression, and increased survival in CRC cell line and patient-derived xenograft models. These data suggest EREG is a promising target for the development of ADCs for treating CRC and other cancer types that express high levels of EREG. While the efficacy of clinically approved anti-EGFR mAbs are largely limited by RAS mutational status, EREG ADCs may show promise for both RAS mutant and wildtype patients, thus improving existing treatment options. Significance: EREG-targeting antibody-drug conjugates demonstrate acceptable safety and robust therapeutic efficacy in RAS mutant and wildtype colorectal cancer, suggesting their potential as an alternative to EGFR-targeted therapy to benefit a broader patient population.

cancer biology↗

bioRxiv2023

Combined multiphoton microscopy and somatostatin receptor type 2 imaging of pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PNETs) are a rare but increasingly more prevalent cancer with heterogeneous clinical and pathological presentation. Surgery is the preferred treatment for all hormone-expressing PNETs and any PNET greater than 2 cm, but difficulties arise when tumors are multifocal, metastatic, or small in size due to lack of effective surgical localization. Existing techniques such as intraoperative ultrasound provide poor contrast and resolution, resulting in low sensitivity for such tumors. Somatostatin receptor type 2 (SSTR2) is commonly overexpressed in PNETs and presents an avenue for targeted tumor localization. SSTR2 is often used for pre-operative imaging and therapeutic treatment, with recent studies demonstrating that somatostatin receptor imaging (SRI) can be applied in radioguided surgery to aid in removal of metastatic lymph nodes and achieving negative surgical margins. However not all PNETs express SSTR2, indicating labeled SRI could benefit from using a supplemental label-free technique such as multiphoton microscopy (MPM), which has proven useful in improving the accuracy of diagnosing more common exocrine pancreatic cancers. Our work tests the suitability of combined SRI and MPM for localizing PNETs by imaging and comparing samples of PNETs and normal pancreatic tissue. Specimens were labeled with a novel SSTR2-targeted contrast agent and imaged using fluorescence microscopy, and subsequently imaged using MPM to collect four autofluo-rescent channels and second harmonic generation. Our results show that a combination of both SRI and MPM provides enhanced contrast and sensitivity for localizing diseased tissue, suggesting that this approach could be a valuable clinical tool for surgical localization and treatment of PNETs.

bioengineering↗