Dina Hany

All Publications

• Hsf1 and the molecular chaperone Hsp90 support a 'rewiring stress response' leading to an adaptive cell size increase in chronic stress ELIFE Maiti, S., Bhattacharya, K., Wider, D., Hany, D., Panasenko, O., Bernasconi, L., Hulo, N., Picard, D. 2023; 12

  Abstract

  Cells are exposed to a wide variety of internal and external stresses. Although many studies have focused on cellular responses to acute and severe stresses, little is known about how cellular systems adapt to sublethal chronic stresses. Using mammalian cells in culture, we discovered that they adapt to chronic mild stresses of up to two weeks, notably proteotoxic stresses such as heat, by increasing their size and translation, thereby scaling the amount of total protein. These adaptations render them more resilient to persistent and subsequent stresses. We demonstrate that Hsf1, well known for its role in acute stress responses, is required for the cell size increase, and that the molecular chaperone Hsp90 is essential for coupling the cell size increase to augmented translation. We term this translational reprogramming the 'rewiring stress response', and propose that this protective process of chronic stress adaptation contributes to the increase in size as cells get older, and that its failure promotes aging.

  View details for DOI 10.7554/eLife.88658

  View details for Web of Science ID 001134824500001

  View details for PubMedID 38059913

  View details for PubMedCentralID PMC10703448

• CRISPR-Cas9 screen reveals a role of purine synthesis for estrogen receptor α activity and tamoxifen resistance of breast cancer cells SCIENCE ADVANCES Hany, D., Vafeiadou, V., Picard, D. 2023; 9 (19): eadd3685

  Abstract

  In breast cancer, resistance to endocrine therapies that target estrogen receptor α (ERα), such as tamoxifen and fulvestrant, remains a major clinical problem. Whether and how ERα+ breast cancers switch from being estrogen-dependent to estrogen-independent remains unclear. With a genome-wide CRISPR-Cas9 knockout screen, we identified previously unknown biomarkers and potential therapeutic targets of endocrine resistance. We demonstrate that high levels of PAICS, an enzyme involved in the de novo biosynthesis of purines, can shift the balance of ERα activity to be more estrogen-independent and tamoxifen-resistant. We find that this may be due to elevated activities of cAMP-activated protein kinase A and mTOR, kinases known to phosphorylate ERα specifically and to stimulate its activity. Genetic or pharmacological targeting of PAICS sensitizes tamoxifen-resistant cells to tamoxifen. Addition of purines renders them more resistant. On the basis of these findings, we propose the combined targeting of PAICS and ERα as a new, effective, and potentially safe therapeutic regimen.

  View details for DOI 10.1126/sciadv.add3685

  View details for Web of Science ID 000996512000006

  View details for PubMedID 37172090

  View details for PubMedCentralID PMC10181187

• Network-informed discovery of multidrug combinations for ERα+/HER2-/PI3Kα-mutant breast cancer CELLULAR AND MOLECULAR LIFE SCIENCES Hany, D., Zoetemelk, M., Bhattacharya, K., Nowak-Sliwinska, P., Picard, D. 2023; 80 (3): 80

  Abstract

  Breast cancer is a persistent threat to women worldwide. A large proportion of breast cancers are dependent on the estrogen receptor α (ERα) for tumor progression. Therefore, targeting ERα with antagonists, such as tamoxifen, or estrogen deprivation by aromatase inhibitors remain standard therapies for ERα + breast cancer. The clinical benefits of monotherapy are often counterbalanced by off-target toxicity and development of resistance. Combinations of more than two drugs might be of great therapeutic value to prevent resistance, and to reduce doses, and hence, decrease toxicity. We mined data from the literature and public repositories to construct a network of potential drug targets for synergistic multidrug combinations. With 9 drugs, we performed a phenotypic combinatorial screen with ERα + breast cancer cell lines. We identified two optimized low-dose combinations of 3 and 4 drugs of high therapeutic relevance to the frequent ERα + /HER2-/PI3Kα-mutant subtype of breast cancer. The 3-drug combination targets ERα in combination with PI3Kα and cyclin-dependent kinase inhibitor 1 (p21). In addition, the 4-drug combination contains an inhibitor for poly (ADP-ribose) polymerase 1 (PARP1), which showed benefits in long-term treatments. Moreover, we validated the efficacy of the combinations in tamoxifen-resistant cell lines, patient-derived organoids, and xenograft experiments. Thus, we propose multidrug combinations that have the potential to overcome the standard issues of current monotherapies.

  View details for DOI 10.1007/s00018-023-04730-x

  View details for Web of Science ID 000943154400002

  View details for PubMedID 36869202

  View details for PubMedCentralID PMC10032341

• Translational reprogramming in response to accumulating stressors ensures critical threshold levels of Hsp90 for mammalian life NATURE COMMUNICATIONS Bhattacharya, K., Maiti, S., Zahoran, S., Weidenauer, L., Hany, D., Wider, D., Bernasconi, L., Quadroni, M., Collart, M., Picard, D. 2022; 13 (1): 6271

  Abstract

  The cytosolic molecular chaperone Hsp90 is essential for eukaryotic life. Although reduced Hsp90 levels correlate with aging, it was unknown whether eukaryotic cells and organisms can tune the basal Hsp90 levels to alleviate physiologically accumulated stress. We have investigated whether and how mice adapt to the deletion of three out of four alleles of the two genes encoding cytosolic Hsp90, with one Hsp90β allele being the only remaining one. While the vast majority of such mouse embryos die during gestation, survivors apparently manage to increase their Hsp90β protein to at least wild-type levels. Our studies reveal an internal ribosome entry site in the 5' untranslated region of the Hsp90β mRNA allowing translational reprogramming to compensate for the genetic loss of Hsp90 alleles and in response to stress. We find that the minimum amount of total Hsp90 required to support viability of mammalian cells and organisms is 50-70% of what is normally there. Those that fail to maintain a threshold level are subject to accelerated senescence, proteostatic collapse, and ultimately death. Therefore, considering that Hsp90 levels can be reduced ≥100-fold in the unicellular budding yeast, critical threshold levels of Hsp90 have markedly increased during eukaryotic evolution.

  View details for DOI 10.1038/s41467-022-33916-3

  View details for Web of Science ID 000871124000045

  View details for PubMedID 36270993

  View details for PubMedCentralID PMC9587034

• Hyperactivation of MAPK Induces Tamoxifen Resistance in SPRED2-Deficient ERα-Positive Breast Cancer CANCERS Vafeiadou, V., Hany, D., Picard, D. 2022; 14 (4)

  Abstract

  Breast cancer is the number one cause of cancer-related mortality in women worldwide. Most breast tumors depend on the expression of the estrogen receptor α (ERα) for their growth. For this reason, targeting ERα with antagonists such as tamoxifen is the therapy of choice for most patients. Although initially responsive to tamoxifen, about 40% of the patients will develop resistance and ultimately a recurrence of the disease. Thus, finding new biomarkers and therapeutic approaches to treatment-resistant tumors is of high significance. SPRED2, an inhibitor of the MAPK signal transduction pathway, has been found to be downregulated in various cancers. In the present study, we found that SPRED2 is downregulated in a large proportion of breast-cancer patients. Moreover, the knockdown of SPRED2 significantly increases cell proliferation and leads to tamoxifen resistance of breast-cancer cells that are initially tamoxifen-sensitive. We found that resistance occurs through increased activation of the MAPKs ERK1/ERK2, which enhances the transcriptional activity of ERα. Treatment of SPRED2-deficient breast cancer cells with a combination of the ERK 1/2 inhibitor ulixertinib and 4-hydroxytamoxifen (4-OHT) can inhibit cell growth and proliferation and overcome the induced tamoxifen resistance. Taken together, these results indicate that SPRED2 may also be a tumor suppressor for breast cancer and that it is a key regulator of cellular sensitivity to 4-OHT.

  View details for DOI 10.3390/cancers14040954

  View details for Web of Science ID 000798698500001

  View details for PubMedID 35205702

  View details for PubMedCentralID PMC8870665