bims-pimaco 2024-07-14 papers

bims-pimaco

Biomed News

on PI3K and MAPK signalling in colorectal cancer

Issue of 2024–07–14
nine papers selected by
Lucas B. Zeiger

TORC2 is required for accumulation of γH2A in response to DNA damage.
Mechanisms of response and tolerance to active RAS inhibition in KRAS-mutant NSCLC.
Assessment of KRASG12C inhibitors for colorectal cancer.
A first-in-class selective inhibitor of EGFR and PI3K offers a single-molecule approach to targeting adaptive resistance.
mTORC2: A neglected player in aging regulation.
Mechanisms of resistance to oncogenic KRAS inhibition in pancreatic cancer.
PI3K PROTAC overcomes the lapatinib resistance in PIK3CA-mutant HER2 positive breast cancer.
High Probability of Lynch Syndrome Among Colorectal Cancer Patients Is Associated With Higher Occurrence of KRAS and PIK3CA Mutations.
Cancer organoids 2.0: modelling the complexity of the tumour immune microenvironment.

J Biol Chem. 2024 Jul 04. pii: S0021-9258(24)02032-5. [Epub ahead of print] 107531

TORC2 is required for accumulation of γH2A in response to DNA damage.

Adiel Cohen, Lea Lubenski, Ava Mouzon, Martin Kupiec, Ronit Weisman.

  TOR protein kinases serve as the catalytic subunit of the TORC1 and TORC2 complexes, which regulate cellular growth, proliferation and survival. In the fission yeast, Schizosaccharomyces pombe, cells lacking TORC2 or its downstream kinase Gad8 (AKT or SGK1 in human cells) exhibit sensitivity to a wide range of stress conditions, including DNA damage stress. One of the first responses to DNA damage is the phosphorylation of C-terminal serine residues within histone H2AX in human cells (γH2AX), or histone H2A in yeast cells (γH2A). The kinases responsible for γH2A in S. pombe are the two DNA damage checkpoint kinases Rad3 and Tel1 (ATR and ATM, respectively, in human cells). Here we report that TORC2-Gad8 signaling is required for accumulation of γH2A in response to DNA damage and during quiescence. Using the TOR specific inhibitor, Torin1, we demonstrate that the effect of TORC2 on γH2A in response to DNA damage is immediate, rather than adaptive. The lack of γH2A is restored by deletion mutations of transcription and chromatin modification factors, including loss of components of Paf1C, SAGA, Mediator and the bromo-domain proteins Bdf1/Bdf2. Thus, we suggest that TORC2-Gad8 may affect the accumulation of γH2A by regulating chromatin structure and function.

Keywords:  DNA damage response; Schizosaccharomyces pombe; TOR complex (TORC); histone H2A phosphorylation; histone modification

DOI:  https://doi.org/10.1016/j.jbc.2024.107531
Cancer Discov. 2024 Jul 08.

Mechanisms of response and tolerance to active RAS inhibition in KRAS-mutant NSCLC.

Haniel A Araujo, Ximo Pechuan-Jorge, Teng Zhou, Minh Truong Do, Xin Hu, Frank R Rojas Alvarez, Maria E Salvatierra, Heladio P Ibarguen, Richard Lee, Rashi Raghulan, Harshit Shah, Mariela A Moreno Ayala, Kevin Chen, Nataliya Tovbis Shifrin, Shuhong Wu, Luisa M Solis Soto, Marcelo V Negrao, Don L Gibbons, David S Hong, Jack A Roth, John V Heymach, Jianjun Zhang, Jingjing Jiang, Mallika Singh, Jacqueline A M Smith, Elsa Quintana, Ferdinandos Skoulidis.

Resistance to inactive state-selective RASG12C inhibitors frequently entails accumulation of RASGTP, rendering effective inhibition of active RAS potentially desirable. Here, we evaluated the anti-tumor activity of the RAS(ON) multi-selective tri-complex inhibitor RMC-7977 and dissected mechanisms of response and tolerance in KRASG12C-mutant NSCLC. Broad-spectrum, reversible RASGTP inhibition with or without concurrent covalent targeting of active RASG12C yielded superior and differentiated antitumor activity across diverse co-mutational KRASG12C-mutant NSCLC mouse models of primary or acquired RASG12C(ON) or (OFF) inhibitor resistance. Interrogation of time-resolved single cell transcriptional responses established an in vivo atlas of multi-modal acute and chronic RAS pathway inhibition in the NSCLC ecosystem and uncovered a regenerative mucinous transcriptional program that supports long-term tumor cell persistence. In patients with advanced KRASG12C-mutant NSCLC, the presence of mucinous histological features portended poor response to sotorasib or adagrasib. Our results have potential implications for personalized medicine and the development of rational RAS inhibitor-anchored therapeutic strategies.

DOI: https://doi.org/10.1158/2159-8290.CD-24-0421
Front Oncol. 2024 ;14 1412435

Assessment of KRASG12C inhibitors for colorectal cancer.

Gary A Piazza, Preethi Chandrasekaran, Yulia Y Maxuitenko, Karim I Budhwani.

  Colorectal cancer (CRC) is a highly prevalent and lethal cancer worldwide. Approximately 45% of CRC patients harbor a gain-in-function mutation in KRAS. KRAS is the most frequently mutated oncogene accounting for approximately 25% of all human cancers. Gene mutations in KRAS cause constitutive activation of the KRAS protein and MAPK/AKT signaling, resulting in unregulated proliferation and survival of cancer cells and other aspects of malignant transformation, progression, and metastasis. While KRAS has long been considered undruggable, the FDA recently approved two direct acting KRAS inhibitors, Sotorasib and Adagrasib, that covalently bind and inactivate KRASG12C. Both drugs showed efficacy for patients with non-small cell lung cancer (NSCLC) diagnosed with a KRASG12C mutation, but for reasons not well understood, were considerably less efficacious for CRC patients diagnosed with the same mutation. Thus, it is imperative to understand the basis for resistance to KRASG12C inhibitors, which will likely be the same limitations for other mutant specific KRAS inhibitors in development. This review provides an update on clinical trials involving CRC patients treated with KRASG12C inhibitors as a monotherapy or combined with other drugs. Mechanisms that contribute to resistance to KRASG12C inhibitors and the development of novel RAS inhibitors with potential to escape such mechanisms of resistance are also discussed.

Keywords:  KRAS G12C inhibitors; KRAS mutation G12C; clinical trials; colorectal cancer; resistance

DOI:  https://doi.org/10.3389/fonc.2024.1412435
Nat Cancer. 2024 Jul 11.

A first-in-class selective inhibitor of EGFR and PI3K offers a single-molecule approach to targeting adaptive resistance.

Christopher E Whitehead, Elizabeth K Ziemke, Christy L Frankowski-McGregor, Rachel A Mumby, June Chung, Jinju Li, Nathaniel Osher, Oluwadara Coker, Veerabhadran Baladandayuthapani, Scott Kopetz, Judith S Sebolt-Leopold.

Despite tremendous progress in precision oncology, adaptive resistance mechanisms limit the long-term effectiveness of molecularly targeted agents. Here we evaluated the pharmacological profile of MTX-531 that was computationally designed to selectively target two key resistance drivers, epidermal growth factor receptor and phosphatidylinositol 3-OH kinase (PI3K). MTX-531 exhibits low-nanomolar potency against both targets with a high degree of specificity predicted by cocrystal structural analyses. MTX-531 monotherapy uniformly resulted in tumor regressions of squamous head and neck patient-derived xenograft (PDX) models. The combination of MTX-531 with mitogen-activated protein kinase kinase or KRAS-G12C inhibitors led to durable regressions of BRAF-mutant or KRAS-mutant colorectal cancer PDX models, resulting in striking increases in median survival. MTX-531 is exceptionally well tolerated in mice and uniquely does not lead to the hyperglycemia commonly seen with PI3K inhibitors. Here, we show that MTX-531 acts as a weak agonist of peroxisome proliferator-activated receptor-γ, an attribute that likely mitigates hyperglycemia induced by PI3K inhibition. This unique feature of MTX-531 confers a favorable therapeutic index not typically seen with PI3K inhibitors.

DOI: https://doi.org/10.1038/s43018-024-00781-6
J Cell Physiol. 2024 Jul 10. e31363

mTORC2: A neglected player in aging regulation.

Weitong Xu, Honghan Chen, Hengyi Xiao.

  Mammalian target of rapamycin (mTOR) is a serine/threonine kinase that plays a pivotal role in various biological processes, through integrating external and internal signals, facilitating gene transcription and protein translation, as well as by regulating mitochondria and autophagy functions. mTOR kinase operates within two distinct protein complexes known as mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2), which engage separate downstream signaling pathways impacting diverse cellular processes. Although mTORC1 has been extensively studied as a pro-proliferative factor and a pro-aging hub if activated aberrantly, mTORC2 received less attention, particularly regarding its implication in aging regulation. However, recent studies brought increasing evidence or clues for us, which implies the associations of mTORC2 with aging, as the genetic elimination of unique subunits of mTORC2, such as RICTOR, has been shown to alleviate aging progression in comparison to mTORC1 inhibition. In this review, we first summarized the basic characteristics of mTORC2, including its protein architecture and signaling network. We then focused on reviewing the molecular signaling regulation of mTORC2 in cellular senescence and organismal aging, and proposed the multifaceted regulatory characteristics under senescent and nonsenescent contexts. Next, we outlined the research progress of mTOR inhibitors in the field of antiaging and discussed future prospects and challenges. It is our pleasure if this review article could provide meaningful information for our readers and call forth more investigations working on this topic.

Keywords:  aging; apoptosis; autophagy; diabetes; mTORC2; neurodegenerative

DOI:  https://doi.org/10.1002/jcp.31363
Cancer Discov. 2024 Jul 08.

Mechanisms of resistance to oncogenic KRAS inhibition in pancreatic cancer.

Julien Dilly, Megan T Hoffman, Laleh Abbassi, Ziyue Li, Francesca Paradiso, Brendan D Parent, Connor J Hennessey, Alexander C Jordan, Micaela Morgado, Shatavisha Dasgupta, Giselle A Uribe, Annan Yang, Kevin S Kapner, Felix P Hambitzer, Li Qiang, Hanrong Feng, Jacob Geisberg, Junning Wang, Kyle E Evans, Hengyu Lyu, Aislyn Schalck, Ningping Feng, Anastasia M Lopez, Christopher A Bristow, Michael P Kim, Kimal I Rajapakshe, Vahid Bahrambeigi, Jennifer A Roth, Kavita Garg, Paola A Guerrero, Ben Z Stanger, Simona Cristea, Scott W Lowe, Timour Baslan, Eliezer M Van Allen, Joseph D Mancias, Emily Chan, Abraham Anderson, Yuliya V Katlinskaya, Alex K Shalek, David S Hong, Shubham Pant, Jill Hallin, Kenna Anderes, Peter Olson, Timothy P Heffernan, Seema Chugh, James G Christensen, Anirban Maitra, Brian M Wolpin, Srivatsan Raghavan, Jonathan A Nowak, Peter S Winter, Stephanie K Dougan, Andrew J Aguirre.

KRAS inhibitors demonstrate clinical efficacy in pancreatic ductal adenocarcinoma (PDAC); however, resistance is common. Among patients with KRASG12C-mutant PDAC treated with adagrasib or sotorasib, mutations in PIK3CA and KRAS, and amplifications of KRASG12C, MYC, MET, EGFR, and CDK6 emerged at acquired resistance. In PDAC cell lines and organoid models treated with the KRASG12D inhibitor MRTX1133, epithelial-to-mesenchymal transition and PI3K-AKT-mTOR signaling associate with resistance to therapy. MRTX1133 treatment of the KrasLSL-G12D/+;Trp53LSL-R172H/+;p48-Cre (KPC) mouse model yielded deep tumor regressions, but drug resistance ultimately emerged, accompanied by amplifications of Kras, Yap1, Myc, and Cdk6/Abcb1a/b, and co-evolution of drug-resistant transcriptional programs. Moreover, in KPC and PDX models, mesenchymal and basal-like cell states displayed increased response to KRAS inhibition compared to the classical state. Combination treatment with KRASG12D inhibition and chemotherapy significantly improved tumor control in PDAC mouse models. Collectively, these data elucidate co-evolving resistance mechanisms to KRAS inhibition and support multiple combination therapy strategies.

DOI: https://doi.org/10.1158/2159-8290.CD-24-0177
Cancer Lett. 2024 Jul 08. pii: S0304-3835(24)00507-X. [Epub ahead of print]598 217112

PI3K PROTAC overcomes the lapatinib resistance in PIK3CA-mutant HER2 positive breast cancer.

Hongyan Zhang, Longlong Zhang, Yuna He, Dewei Jiang, Jian Sun, Qianmei Luo, Huichun Liang, Tiantian Wang, Fubing Li, Yu Tang, Zimo Yang, Wenjing Liu, Yu Rao, Ceshi Chen.

  Although anti-HER2 therapy has made significant strides in reducing metastasis and relapse in HER2-positive breast cancer, resistance to agents like trastuzumab, pertuzumab, and lapatinib frequently develops in patients undergoing treatment. Previous studies suggest that the hyperactivation of the PI3K-AKT signaling pathway by PIK3CA/PTEN gene mutations is implicated in HER2 resistance. In this study, we introduce a novel PI3K-p110α Proteolysis TAargeting Chimera (PROTAC) that effectively inhibits the proliferation of breast cancer cells by degrading PI3K-p110α. When tested in two lapatinib-resistant cell lines, JIMT1 and MDA-MB-453, both of which harbor PIK3CA mutations, the PI3K PROTAC notably reduced cell proliferation and induced G1 phase cell cycle arrest. Importantly, even at very low concentrations, PI3K PROTAC restored sensitivity to lapatinib. Furthermore, the efficacy of PI3K PROTAC surpassed that of Alpelisib, a selective PI3K-p110α kinase inhibitor in clinic. The superior performance of PI3K PROTAC was also confirmed in lapatinib-resistant breast cancer xenograft tumors and patient-derived breast cancer organoids (PDOs). In conclusion, this study reveals that the novel PI3K PROTAC we synthesized could serve as an effective agent to overcome lapatinib resistance.

Keywords:  AKT; Alpelisib; HER2 resistance; Lapatinib; PI3K; PIK3CA mutation; PROTAC

DOI:  https://doi.org/10.1016/j.canlet.2024.217112
World J Oncol. 2024 Aug;15(4): 612-624

High Probability of Lynch Syndrome Among Colorectal Cancer Patients Is Associated With Higher Occurrence of KRAS and PIK3CA Mutations.

Didik Setyo Heriyanto, Naomi Yoshuantari, Gilang Akbariani, Vincent Lau, Hanifa Hanini, Zulfa Hidayati, Muhammad Zulfikar Arief, Andrew Nobiantoro Gunawan, Asep Muhamad Ridwanuloh, Wien Kusharyoto, Adeodatus Yuda Handaya, Mohammad Ilyas, Johan Kurnianda, Susanna Hilda Hutajulu, Susanti Susanti.

   Background: In Indonesia, early-onset colorectal cancer (EOCRC) rates are higher in patients < 50 years old compared to Western populations, possibly due to a higher frequency of Lynch syndrome (LS) in CRC patients. We aimed to examine the association of KRAS and PIK3CA mutations with LS.
Methods: In this retrospective cross-sectional single-center study, the PCR-HRM-based test was used for screening of microsatellite instability (MSI) mononucleotide markers (BAT25, BAT26, BCAT25, MYB, EWSR1), MLH1 promoter methylation, and oncogene mutations of BRAF (V600E), KRAS (exon 2 and 3), and PIK3CA (exon 9 and 20) in FFPE DNA samples.
Results: All the samples (n = 244) were from Dr. Sardjito General Hospital Yogyakarta, Indonesia. KRAS and PIK3CA mutations were found in 151/244 (61.88%) and 107/244 (43.85%) of samples, respectively. KRAS and PIK3CA mutations were significantly associated with MSI status in 32/42 (76.19%) and 25/42 (59.52%) of samples, respectively. KRAS mutation was significantly associated with LS status in 26/32 (81.25%) of samples. The PIK3CA mutation was present in a higher proportion in LS samples of 19/32 (59.38%), but not statistically significant. Clinicopathology showed that KRAS mutation was significantly associated with right-sided CRC and higher histology grade in 39/151 (25.83%) and 24/151 (16.44%) samples, respectively. PIK3CA mutation was significantly associated with female sex and lower levels of tumor-infiltrating lymphocytes in 62/107 (57.94%) and 26/107 (30.23%) samples, respectively. KRAS and PIK3CA mutations did not significantly affect overall survival (120 months) in LS and non-LS patients.
Conclusions: The high probability of LS in Indonesian CRC patients is associated with KRAS and PIK3CA mutations.

Keywords:  Colorectal neoplasms; Gastrointestinal neoplasms; Hereditary; Medical oncology; Molecular; Neoplastic syndromes; Pathology

DOI:  https://doi.org/10.14740/wjon1843
Nat Rev Cancer. 2024 Jul 08.

Cancer organoids 2.0: modelling the complexity of the tumour immune microenvironment.

Roel Polak, Elisa T Zhang, Calvin J Kuo.

The development of neoplasia involves a complex and continuous interplay between malignantly transformed cells and the tumour microenvironment (TME). Cancer immunotherapies targeting the immune TME have been increasingly validated in clinical trials but response rates vary substantially between tumour histologies and are often transient, idiosyncratic and confounded by resistance. Faithful experimental models of the patient-specific tumour immune microenvironment, capable of recapitulating tumour biology and immunotherapy effects, would greatly improve patient selection, target identification and definition of resistance mechanisms for immuno-oncology therapeutics. In this Review, we discuss currently available and rapidly evolving 3D tumour organoid models that capture important immune features of the TME. We highlight diverse opportunities for organoid-based investigations of tumour immunity, drug development and precision medicine.

DOI: https://doi.org/10.1038/s41568-024-00706-6