Sonic Hedgehog Pathway as the Prognostic Marker in Patients with Extensive Stage Small Cell Lung Cancer

The therapeutic effect of DX2 inhibition in nicotine-induced lung cancer progression

Alternative splicing products of AIMP2 and AIMP2-DX2 (DX2) have been reported to be associated with human lung cancer. In fact, DX2 expression is elevated in human lung cancers, and DX2 transgenic mice also develop lung cancer, in particular small cell lung cancer (SCLC). However, the mechanism by which DX2 is induced during cancer progression has not been clearly elucidated. Here, we show that DX2 is induced by nicotine, the main component of smoking-related chemicals, which can stabilize the human epidermal growth factor receptor 2 (HER2) protein and transcriptionally increase sonic hedgehog (Shh). Indeed, nicotine showed tumorigenicity via DX2 by promoting spheroid formation and in vivo lung and kidney cancer progression. Moreover, the elimination of DX2 using small interfering RNA (siRNA) or an optimized inhibitor (SNU-14) blocked the induction of HER2 and Shh and completely suppressed tumor sphere formation in response to nicotine. These results indicate that DX2 is critical for lung cancer progression, and a specific DX2 inhibitor would be useful for the treatment of human cancers, including SCLC and non-SCLC (NSCLC).

Sonic hedgehog expression in steatohepatitic hepatocellular carcinoma and its clinicopathological significance

Hedgehog (Hh) signaling pathway dysregulation is involved in the pathogenesis of metabolic dysfunction-associated steatohepatitis, and the sonic Hh (SHh) protein, a pivotal molecule in the Hh pathway, is expressed in ballooned hepatocytes. The present study aimed to investigate the clinicopathological significance of SHh expression in steatohepatitic hepatocellular carcinoma (SH-HCC). Reverse transcription-quantitative polymerase chain reaction and immunohistochemistry were performed to examine SHh gene and SHh protein expression in SH-HCC. Additionally, patients with conventional HCC (C-HCC) were included in the control group. Comparisons of patient and tumor characteristics were also performed. The prevalence of SH-HCC was 3% in the whole cohort, and it was significantly associated with a high prevalence of diabetes mellitus. SHh mRNA was detected in all patients with SH-HCC, but not in 23% of patients with C-HCC. Notably, SHh mRNA expression was not significantly different between patients with SH-HCC and those with C-HCC; however, high SHh protein expression was significantly more frequent in SH-HCC patients than in those with C-HCC. Although the prognosis was not significantly different between the SH-HCC and C-HCC groups, high SHh protein expression was an independent poor prognostic factor for HCC. In conclusion, SHh could potentially serve as a therapeutic target for patients with HCC.

Activated hedgehog gene pattern correlates with dismal clinical outcome and tumor microenvironment heterogeneity in hepatocellular carcinoma

Background

Activation of the Hedgehog signaling pathway is linked to the initiation and development of human hepatocellular carcinoma (HCC). However, its impact on clinical outcomes and the HCC microenvironment remains unclear.

Methods

We performed comprehensive analyses of Hedgehog pathway genes in a large cohort of HCC patients. Specifically, we utilized univariate Cox regression analysis to identify Hedgehog genes linked to overall survival, and the LASSO algorithm was used to construct a Hedgehog-related gene pattern. We subsequently examined the correlation between the Hedgehog pattern and the HCC microenvironment employing the CIBERSORT and ssGSEA algorithms. Furthermore, Tumor Immune Dysfunction and Exclusion (TIDE) algorithm and the anti-PD-L1 treatment dataset (IMvigor210) are used to evaluate the clinical response of the Hedgehog pattern in predicting immune checkpoint inhibitors.

Results

We found that the Hedgehog activation score (HHAS), a prognostic score based on 11 Hedgehog genes, was significantly associated with HCC patient survival. Patients exhibiting high HHAS experienced markedly reduced survival rates compared to those with low HHAS, and HHAS emerged as an independent prognostic factor for HCC. Functional enrichment analysis unveiled the association of the HHAS phenotype with functions related to the immune system, and further investigation demonstrated that HCC patients exhibiting low HHAS displayed elevated levels of anti-tumor immune activation in CD8+ T cells, while high HHAS were linked to immune escape phenotypes and increased infiltration of immune suppressive cells. In addition, in the Immune Checkpoint Inhibitor (ICI) cohort of IMvigor210, patients with higher HHAS had worse ICI treatment outcomes and shortened survival time, indicating that the HHAS is a useful indicator for predicting patient response to immunotherapy.

Conclusions

In summary, our study offers valuable insights for advancing research on Hedgehog and its impact on tumor immunity, which provides an opportunity to optimize prognosis and immune therapy for HCC.

Importance of targeting various cell signaling pathways in solid cancers

Most adult human cancers are solid tumors prevailing in vital organs and lead to mortality all over the globe. Genetic and epigenetic alterations in cancer genes or genes of associated signaling pathways impart the most common characteristic of malignancy, that is, uncontrolled proliferation. Unless the mechanism of action of these cells signaling pathways (involved in cell proliferation, apoptosis, metastasis, and the maintenance of the stemness of cancer stem cells and cancer microenvironment) and their physiologic alteration are extensively studied, it is challenging to understand tumorigenesis as well as develop new treatments and precision medicines. Targeted therapy is one of the most promising strategies for treating various cancers. However, cancer is an evolving disease, and most patients develop resistance to these drugs by acquired mutations or mediation of microenvironmental factors or due to tumor heterogeneity. Researchers are striving to develop novel therapeutic options like combinatorial approaches targeting multiple responsible pathways effectively. Thus, in-depth knowledge of cell signaling and its components remains a critical topic of cancer research. This chapter summarized various extensively studied pathways in solid cancer and how they are targeted for therapeutic strategies.

A clinicopathological exploration of Hedgehog signaling: implications in oral carcinogenesis

INTRODUCTION

Hedgehog Signaling, a basic cancer stem cell pathway, plays a major role during the embryonic development, is known to play a quiescent role in adults. However, aberrant activation of Hedgehog signaling in adults is known to play a role in cancer development. Hence, the aim of the study was to identify the role of Hedgehog signaling pathway in the Oral cancers.

MATERIALS AND METHODS

The expression of Hedgehog signaling pathway was evaluated in 124 patients through the quantitative real-time PCR. The association between the gene expression and clinico-pathological parameters were analyzed using the Pearson chi-square test and survival analysis was carried out using Kaplan-Meier analysis.

RESULTS

SHH and GLI1 was found to be significantly associated with the Lymph Node Status and SUFU was significantly associated with the Age. SMO and SUFU were found to have a worse prognosis in oral cancer patients. According to our findings, IHH plays a critical role in the activation of the HH signaling pathway in oral cancer.

CONCLUSION

These findings back up the use of the Hedgehog signaling pathway as a biomarker for early disease prediction in oral cancer, as well as its role in tumor aggressiveness and invasiveness.

The Role of Hedgehog Signaling Pathway in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the sixth leading malignancy worldwide, with a poor prognosis and limited treatment options. Molecularly targeted therapies for HNSCC are still lacking. However, recent reports provide novel insights about many molecular alterations in HNSCC that may be useful in future therapies. Therefore, it is necessary to identify new biomarkers that may provide a better prediction of the disease and promising targets for personalized therapy. The poor response of HNSCC to therapy is attributed to a small population of tumor cells called cancer stem cells (CSCs). Growing evidence indicates that the Hedgehog (HH) signaling pathway plays a crucial role in the development and maintenance of head and neck tissues. The HH pathway is normally involved in embryogenesis, stem cell renewal, and tissue regeneration. However, abnormal activation of the HH pathway is also associated with carcinogenesis and CSC regulation. Overactivation of the HH pathway was observed in several tumors, including basal cell carcinoma, that are successfully treated with HH inhibitors. However, clinical studies about HH pathways in HNSCC are still rare. In this review, we summarize the current knowledge and recent advances regarding the HH pathway in HNSCC and discuss its possible implications for prognosis and future therapy.

Orchestrating smart therapeutics to achieve optimal treatment in small cell lung cancer: recent progress and future directions

Small cell lung cancer (SCLC) is a recalcitrant malignancy with elusive mechanism of pathogenesis and dismal prognosis. Over the past decades, platinum-based chemotherapy has been the backbone treatment for SCLC. However, subsequent chemoresistance after initial effectiveness urges researchers to explore novel therapeutic targets of SCLC. Recent years have witnessed significant improvements in targeted therapy in SCLC. New molecular candidates such as Ataxia telangiectasia and RAD3-related protein (ATR), WEE1, checkpoint kinase 1 (CHK1) and poly-ADP-ribose polymerase (PARP) have shown promising therapeutic utility in SCLC. While immune checkpoint inhibitor (ICI) has emerged as an indispensable treatment modality for SCLC, approaches to boost efficacy and reduce toxicity as well as selection of reliable biomarkers for ICI in SCLC have remained elusive and warrants our further investigation. Given the increasing importance of precision medicine in SCLC, optimal subtyping of SCLC using multi-omics have gradually applied into clinical practice, which may identify more drug targets and better tailor treatment strategies to each individual patient. The present review summarizes recent progress and future directions in SCLC. In addition to the emerging new therapeutics, we also focus on the establishment of predictive model for early detection of SCLC. More importantly, we also propose a multi-dimensional model in the prognosis of SCLC to ultimately attain the goal of accurate treatment of SCLC.

GLIS2 and CCND1 expression levels in breast cancer patients

BACKGROUND

Breast cancer (BC) is the most prevalent cancer in women, with increasing incidence and death rates in recent years. Disruptions of different signaling pathways partially cause breast cancer. Hence, different genes through particular pathways are involved in BC tumorigenesis.

METHODS

In this study, we evaluated the expression level of GLIS2 and CCND1 genes in 50 patients. Also, in-silico analyses were used to enrich related signaling pathways involving the mentioned genes.

RESULTS

The results showed an increased expression level of Cyclin D1 and decreased expression level of GLIS2 in BC patients. Moreover, a relationship between aberrant expression levels of GLIS2 and CCND1 and BC development was determined.

CONCLUSION

These observations could help uncover new therapeutic targets for treating patients with BC in the progressive stage.

ADAM12 is an independent predictor of poor prognosis in liver cancer

Disintegrin and metalloproteinase 12 (ADAM12) is thought to trigger the occurrence and development of numerous tumours, including colorectal, breast, and pancreatic cancers. On the basis of The Cancer Genome Atlas (TCGA) datasets, in this study, the relationship between ADAM12 gene expression and hepatocellular carcinoma (HCC), the prognostic value of this relationship, and the potential mechanisms influencing HCC development were evaluated. The results showed that the ADAM12 gene was significantly and highly expressed in liver cancer tissue. The high expression of the ADAM12 gene in liver cancer tissue significantly and positively correlated with T stage, pathological stage, and residual tumour. Kaplan–Meier and Cox regression analyses revealed that ADAM12 gene expression is an independent risk factor influencing the prognosis of patients with liver cancer. Pathway analyses of ADAM12 in HCC revealed ADAM12-correlated signalling pathways, and the expression level of ADAM12 was associated with immune cell infiltration. In vitro experiments demonstrated that the expression level of ADAM12 in Huh-7 and Hep3B cells was significantly higher than that in other HCC cells. ShRNA transfection experiments confirmed that the expression levels of TGF-β and Notch pathway-related proteins were significantly decreased. An EdU cell proliferation assay showed that a low level of ADAM12 gene expression significantly inhibited the proliferative activity of HCC cells. Cell cycle experiments showed that low ADAM12 expression blocked the G1/S phase transition. Overall, this research revealed that high ADAM12 gene expression implies a poor prognosis for patients with primary liver cancer. In addition, it is a potential indicator for the diagnosis of liver cancer.

Molecular Mechanisms Involving the Sonic Hedgehog Pathway in Lung Cancer Therapy: Recent Advances

According to the latest statistics from the International Agency for Research on Cancer (IARC), lung cancer is one of the most lethal malignancies in the world, accounting for approximately 18% of all cancer-associated deaths. Yet, even with aggressive interventions for advanced lung cancer, the five-year survival rate remains low, at around 15%. The hedgehog signaling pathway is highly conserved during embryonic development and is involved in tissue homeostasis as well as organ development. However, studies have documented an increasing prevalence of aberrant activation of HH signaling in lung cancer patients, promoting malignant lung cancer progression with poor prognostic outcomes. Inhibitors targeting the HH pathway have been widely used in tumor therapy, however, they still cannot avoid the occurrence of drug resistance. Interestingly, natural products, either alone or in combination with chemotherapy, have greatly improved overall survival outcomes for lung cancer patients by acting on the HH signaling pathway because of its unique and excellent pharmacological properties. In this review, we elucidate on the underlying molecular mechanisms through which the HH pathway promotes malignant biological behaviors in lung cancer, as well as the potential of inhibitors or natural compounds in targeting HH signaling for clinical applications in lung cancer therapy.

Small Cell Lung Cancer: State of the Art of the Molecular and Genetic Landscape and Novel Perspective

Simple Summary

Small cell lung cancer (SCLC) continues to carry a poor prognosis with a five-year survival rate of 3.5% and a 10-year survival rate of 1.8%. The pathogenesis remains unclear, and there are no known predictive or diagnostic biomarkers. The current SCLC classification as a single entity hinders effective targeted therapies against this heterogeneous neoplasm. Despite dedicated decades of research and clinical trials, there has been no change in the SCLC treatment paradigm. This review summarizes the body of literature available on SCLC’s genomic landscape to describe SCLC’s molecular/genetic aspects, regardless of therapeutic strategy.

Abstract

Small cell lung cancer (SCLC) is a highly proliferative lung cancer that is not amenable to surgery in most cases due to the high metastatic potential. Precision medicine has not yet improved patients’ survival due to the lack of actionable mutations. Intra- and intertumoral heterogeneity allow the neoplasms to adapt to various microenvironments and treatments. Further studying this heterogeneous cancer might yield the discovery of actionable mutations. First-line SCLC treatment has added immunotherapy to its armamentarium. There has been renewed interest in SCLC, and numerous clinical trials are underway with novel therapeutic approaches. Understanding the molecular and genetic landscape of this heterogeneous and lethal disease will pave the way for novel drug development.

Understanding the Hedgehog Signaling Pathway in Acute Myeloid Leukemia Stem Cells: A Necessary Step toward a Cure

Simple Summary

The Hedgehog signaling pathway is related to the cell cycle. In particular, it is considered to play a fundamental role in the quiescence of leukemic stem cell (i.e., a temporary resting state without cell replication). Leukemic stem cells are the cells supposed to give rise to the relapses of the leukemia. Therefore, the Hedgehog pathway must be understood to improve the current treatments against acute myeloid leukemia and avoid the relapse of the disease. In this review, we gather the present knowledge about the physiological Hedgehog pathway function, the aberrant activation of Hedgehog in leukemia, and highlight the lack of evidence regarding some aspects of this important pathway. Finally, we summarize the acute myeloid leukemia treatments targeting this signaling pathway.

Abstract

A better understanding of how signaling pathways govern cell fate is fundamental to advances in cancer development and treatment. The initialization of different tumors and their maintenance are caused by the deregulation of different signaling pathways and cancer stem cell maintenance. Quiescent stem cells are resistant to conventional chemotherapeutic treatments and, consequently, are responsible for disease relapse. In this review we focus on the conserved Hedgehog (Hh) signaling pathway which is involved in regulating the cell cycle of hematopoietic and leukemic stem cells. Thus, we examine the role of the Hh signaling pathway in normal and leukemic stem cells and dissect its role in acute myeloid leukemia. We explain not only the connection between illness and the signaling pathway but also evaluate innovative therapeutic approaches that could affect the outcome of patients with acute myeloid leukemia. We found that many aspects of the Hedgehog signaling pathway remain unknown. The role of Hh has only been proven in embryo and hematopoietic stem cell development. Further research is needed to elucidate the role of GLI transcription factors for therapeutic targeting. Glasdegib, an SMO inhibitor, has shown clinical activity in acute myeloid leukemia; however, its mechanism of action is not clear.

Hedgehog Signaling, a Critical Pathway Governing the Development and Progression of Hepatocellular Carcinoma

Hedgehog (Hh) signaling is a classic morphogen in controlling embryonic development and tissue repairing. Aberrant activation of Hh signaling has been well documented in liver cancer, including hepatoblastoma, hepatocellular carcinoma (HCC) and cholangiocarcinoma. The present review aims to update the current understanding on how abnormal Hh signaling molecules modulate initiation, progression, drug resistance and metastasis of HCC. The latest relevant literature was reviewed with our recent findings to provide an overview regarding the molecular interplay and clinical relevance of the Hh signaling in HCC management. Hh signaling molecules are involved in the transformation of pre-carcinogenic lesions to malignant features in chronic liver injury, such as nonalcoholic steatohepatitis. Activation of GLI target genes, such as ABCC1 and TAP1, is responsible for drug resistance in hepatoma cells, with a CD133⁻/EpCAM⁻ surface molecular profile, and GLI1 and truncated GLI1 account for the metastatic feature of the hepatoma cells, with upregulation of matrix metalloproteinases. A novel bioassay for the Sonic Hh ligand in tissue specimens may assist HCC diagnosis with negative α-fetoprotein and predict early microvascular invasion. In-depth exploration of the Hh signaling deepens our understanding of its molecular modulation in HCC initiation, drug sensitivity and metastasis, and guides precise management of HCC on an individual basis.

Downregulation of miR-506-3p Facilitates EGFR-TKI Resistance through Induction of Sonic Hedgehog Signaling in Non-Small-Cell Lung Cancer Cell Lines

Non-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutation eventually develop resistance to EGFR-targeted tyrosine kinase inhibitors (TKIs). Treatment resistance remains the primary obstacle to the successful treatment of NSCLC. Although drug resistance mechanisms have been studied extensively in NSCLC, the regulation of these mechanisms has not been completely understood. Recently, increasing numbers of microRNAs (miRNAs) are implicated in EGFR-TKI resistance, indicating that miRNAs may serve as novel targets and may hold promise as predictive biomarkers for anti-EGFR therapy. MicroRNA-506 (miR-506) has been identified as a tumor suppressor in many cancers, including lung cancer; however, the role of miR-506 in lung cancer chemoresistance has not yet been addressed. Here we report that miR-506-3p expression was markedly reduced in erlotinib-resistant (ER) cells. We identified Sonic Hedgehog (SHH) as a novel target of miR-506-3p, aberrantly activated in ER cells. The ectopic overexpression of miR-506-3p in ER cells downregulates SHH signaling, increases E-cadherin expression, and inhibits the expression of vimentin, thus counteracting the epithelial-mesenchymal transition (EMT)-mediated chemoresistance. Our results advanced our understanding of the molecular mechanisms underlying EGFR-TKI resistance and indicated that the miR-506/SHH axis might represent a novel therapeutic target for future EGFR mutated lung cancer treatment.

Novel aptasensor-based assay of sonic hedgehog ligand for detection of portal vein invasion of hepatocellular carcinoma

The high expression of sonic hedgehog ligand (SHh) is closely correlated to the metastasis, drug resistance and poor prognosis of hepatocellular carcinoma (HCC). Therefore, sensitive, specific and efficient detection methods for SHh are needed for the early diagnosis and assessment of prognosis. Herein, an aptamer, AP32 that specifically binds to SHh (K_D = 25.7 ± 4.1 nM) was obtained by SELEX technology with further optimization. In vivo experiments confirmed that AP32 has the potential to be an imaging probe for Huh-7 cell-derived xenograft. The interaction mode in 3-dimensional configuration between the aptamer and SHh was established by molecular simulation and confirmed by mutations at key sites of the aptamer. An aptasensor-based assay was successfully developed by conjugating Texas-Red-labeled AP32 to microbeads, and was used to analyze SHh content in hepatoma cell lysates, serum and HCC specimens. The method exhibited a broad detection range from 0.07 to 62.5 nM with a low detection limit of 69 pM, and a recovery rate of 104.6 ± 3.9% in serum. When the assay was used to measure SHh content in tissue lysates, the results demonstrated that it possessed 57.1% positivity, 100% specificity in distinguishing 28 HCC specimens from normal tissues, and was compensatory for detection of HCC in AFP-negative cases. Moreover, elevated SHh levels are indicative of portal vein invasion at 77.8% positive rate. This novel aptasensor-based SHh assay may offer a reliable means in predicting early metastasis and poor prognosis in hepatocellular carcinoma.

Metformin upregulates the expression of Gli1 in vascular endothelial cells in hyperoxia-exposed neonatal mice

Bronchopulmonary dysplasia (BPD) is characterized by arrested alveolar and vascular development in premature infants. Metformin protects against the cardiovascular impairment induced by diabetes. The aim of this study was to investigate whether metformin could also enhance pulmonary vascular development in hyperoxic neonatal mice and investigate possible mechanisms involved. C57BL/6J newborn mice were randomly assigned to either of two groups - the room air group or the hyperoxia group - within 12 h postnatally. The mice were subcutaneously injected with metformin (100 mg/kg) or saline for 14 days. Lung morphology and PECAM-1 (CD31) expression in the lung were evaluated at postnatal days 7 and 14. Ki-67 and Gli1 expression in vascular endothelial cells was evaluated at postnatal day 14 by immunofluorescence staining. Flow cytometry (FCM) was also used to analyze Gli1 expression. Human umbilical vein endothelial cell (HUVECs) were used to investigate the role of metformin in vascular proliferation and tubular formation under 90% oxygen in vitro by cell counting Kti-8 (CCK8) assays and tube formation assays. Exposure to hyperoxia resulted in impaired lung development in newborn mice. Metformin enhanced the terminal airspace and radial alveolar count in newborn mice thus exposed. Immunohistochemistry staining and western blot assays revealed that metformin enhanced the expression of CD31 in hyperoxia-exposed newborn mice. Immunofluorescence staining showed that metformin enhanced the expression of Ki-67 in vascular endothelial cells. Furthermore, both immunofluorescence staining and FCM demonstrated that metformin increased Gli1 expression in vascular endothelial cells. Additionally, cell counting Kit-8 (CCK8) and viability assays of HUVECs in vitro both indicated that metformin improved the vascular proliferation and tube formation of HUVECs under 90% oxygen. These results indicated that metformin enhanced lung vascular development and upregulated the expression of Gli1 in the pulmonary vascular endothelial cells in hyperoxic neonatal mice.

Regulation of epithelial-mesenchymal transition via sonic hedgehog/glioma-associated oncogene homolog 1 signaling pathway in peritoneal mesothelial cells

Sonic hedgehog (Shh) signaling regulating epithelial-mesenchymal transition (EMT) in cultured rat peritoneal mesothelial cells (PMCs) remains an under-investigated topic. The current study aimed to elucidate the role of Shh signaling in the regulation of EMT in PMCs to attenuate peritoneal injury, with the view of enhancing the efficacy of peritoneal dialysis (PD). PMCs were initially extracted from male Wistar rats using pancreatic enzyme digestion. The expression of Shh and glioma-associated oncogene homolog (Gli1) was quantitatively analyzed using the reverse-transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. Migration of PMCs was determined using Transwell assay. The expression of Shh, Gli1, and EMT markers including α-smooth muscle actin (α-SMA), fibronectin, collagen I, snail1, and E-cadherin was examined by RT-qPCR, western blot analysis, and immunofluorescence respectively. High glucose induction was identified to promote cell migration and increase the expression of Shh and Gli1 in a dose- and time-dependent manner in rat PMCs. Cyclopamine (CPN) was observed to block the Shh signaling induced by high glucose, accompanied by cell migration inhibition, decreased expression of α-SMA, fibronectin, collagen I and snail1 as well as increased expression of E-cadherin. Altogether, overexpression of Gli1 by transfected Gli1 plasmid promotes cell migration and upregulates α-SMA, fibronectin, Snail1, and collagen I expression, while downregulating E-cadherin expression. Shh/Gli1 signaling is important in mediating EMT in rat PMCs, which provides a potential novel therapeutic approach for clinical investigation on renal failure treatment.

Sonic Hedgehog Signaling in Organogenesis, Tumors, and Tumor Microenvironments

During mammalian embryonic development, primary cilia transduce and regulate several signaling pathways. Among the various pathways, Sonic hedgehog (SHH) is one of the most significant. SHH signaling remains quiescent in adult mammalian tissues. However, in multiple adult tissues, it becomes active during differentiation, proliferation, and maintenance. Moreover, aberrant activation of SHH signaling occurs in cancers of the skin, brain, liver, gallbladder, pancreas, stomach, colon, breast, lung, prostate, and hematological malignancies. Recent studies have shown that the tumor microenvironment or stroma could affect tumor development and metastasis. One hypothesis has been proposed, claiming that the pancreatic epithelia secretes SHH that is essential in establishing and regulating the pancreatic tumor microenvironment in promoting cancer progression. The SHH signaling pathway is also activated in the cancer stem cells (CSC) of several neoplasms. The self-renewal of CSC is regulated by the SHH/Smoothened receptor (SMO)/Glioma-associated oncogene homolog I (GLI) signaling pathway. Combined use of SHH signaling inhibitors and chemotherapy/radiation therapy/immunotherapy is therefore key in targeting CSCs.